Poor Intubations in EMS

[Spock]

Can I come up to the Green Mountain State and precept the "I-tech"? That would be fun! Can you say new rectum?

Live long and prosper

Spock

[TechMedic05]

Spock, you're welcome any time! Just gimme a PM heh heh heh

[EmergencyMedicalTigger]

I am new to the forum but have a little story to share with you about combitubes and the lack of training at even the I-tech level...

the other day I was talking to an I-tech that had responded to a "unknown medical" that turned into a working code on arrival... the medic was called and a Combitube was placed... it was pulled by the medic who successfully intubated this patient. Later at the hospital while speaking to the I-tech He was very proud that he got this combitube place correctly.. I was wondering why he was so ecstatic then he told me that he is 1for2 in his combitubes!!!!! I was shocked... how do you MISS with a one shot does not matter where the tube goes airway? he informed me that he could not hear lung sounds in the bases and that he had belly sounds with both tubes... as the conversation went on he said that he use the deflector this time because last time he was hit with.... and I quote "VOMIT FROM THE TUBE" on his last attempt...

JJ

Hmmm, maybe he's not inflating the cuffs on the combitube enough....?

[firemedic78]

on the comment about ventilating a patient with a mis-placed tube in the esoph...

since we're quoting 'National Standards', i might add that you typically have a partner who helps you in the process of intubation. I know...not always! However, per the N.R. skill sheet, you have a partner hyperventilate prior to tube insertion.

Now...that being said...if you miss. You can have your partner prep another tube asap, and have the scope in the patients mouth about the same time. This should only take a few seconds. Maybe 30 at most. I know...30 seconds w/o air movement. However lets look at the alternative. 30 more seconds vs. 2 or 3 more attempts of 45seconds to a minute each!

Which is the better option?

[fireflymedic]

I am wondering if some of this isn't due to not checking the tube placement every time a patient is moved. It still amazes me how easily they can become dislodged. Medic programs in this area have very strong intubation clinicals (you spend lots of time getting to know the anesthesiologists in the area). Plus they teach you how to bag properly (it's amazing how few people actually KNOW how to bag a patient...I thought I did, then I met my preceptor). I would think it a good thing for medics to have to do a routine rotation every year to polish up on skills they don't use that often or confirm their skills. Instead, many times they are left to have a skill unused for sometimes several years, then called upon to use it and it goes badly (example, I watched a service with a former flight medic director who had gotten RSI approved in their protocols, did little training with it, they didn't use it in over two years, then one day needed it, and couldn't get the tube....bad things started happening). Gotta keep those skills up, same goes for basics !

[Ace844]

Hello Everyone,

Here's a recent study which shows that even in hospital ETI and RSI have many of the same complications we experience.... So as you can see this doesn't just happen to us...

Hope This Helps,

ACE844

(Clinical practice and risk factors for immediate complications of

endotracheal intubation in the intensive care unit: A prospective @

multiple-center study*

Samir Jaber, MD, PhD; Jibba Amraoui, MD; Jean-Yves Lefrant, MD, PhD; Charles Arich, MD;

Robert Cohendy, MD, PhD; Liliane Landreau, MD; Yves Calvet, MD; Xavier Capdevila, MD, PhD;

Aba Mahamat, MD; Jean-Jacques Eledjam, MD, PhD)

Emergency endotracheal intubation (ETI) in critically ill patients can be fraught with mild to severe life-threatening complications related to hemodynamic alterations and difficulty with oxygenation and ventilation (1–4). In the intensive care unit (ICU), this procedure differs significantly

from ETI carried out for routine surgical procedures (5–9). In the operating room, most intubations are performed under elective controlled conditions by anesthesiologists experienced in airway management (8, 10, 11). The rate of complications is relatively low (8, 10, 11). In the ICU, tracheal intubations are frequently done urgently to treat severe respiratory failure and/or as part of cardiorespiratory resuscitation

(1–3, 12). Tracheal intubation is sometimes done electively, but diseases that require mechanical ventilation often necessitate rapid endotracheal intubation to avoid arterial desaturation. Emergency ETI performed outside the operating room has been studied more often in prehospital settings (13, 14) and in emergency departments (13, 14). Only two studies have focused on the complications related to ETI performed in the ICU. Schwartz et al. (1) performed a descriptive study in three ICUs of a single institution, investigating the complications of emergency airway management in 297 critically ill patients carried out by the ICU team. Le Tacon et al. (2), in a prospective study on relatively small cohort (n 80), performed a single-center evaluation of the frequency of difficult ETI and listed the related complications. No study

has focused on potential conditions that could be considered as risk factors for complications associated with ETI and reported associated hemodynamic complications. Therefore, a multiple-center observational study was performed in seven French ICUs to describe the current practice of physicians, to report complications associated with endotracheal intubation in ICU, and to isolate predictive factors of immediate life-threatening complications.

PATIENTS AND METHODS

Eligibility Criteria

The present observational study was performed in seven southern French ICUs (three *See also p. 00. From the Intensive Care Unit, Department of Anesthesiology B, DAR B CHU de Montpellier, Hôpital Saint Eloi, Université Montpellier 1, Montpellier, cedex 5 France (SJ, JA, JJE); Fédération Anesthésie-Douleur-Urgences- Réanimation, Groupe Hospitalo-Universitaire Caremeau, Centre Hospitalier Universitaire Nîmes, Nîmes cedex 9,France (JA, JYL, CA, RC); Service de réanimation médicale assistance respiratoire, CHU de Montpellier, Hôpital Gui-de-Chauliac, Montpellier cedex 5, France (LL); Réanimation polyvalente, Clinique du Parc, Castelnau-le-Lez, France (YC); Intensive Care Unit, Department of Anesthesiology A, DAR A CHU de Montpellier, Hôpital Lapeyronie, Montpellier, cedex 5 France (XC); and Département d’Information Médicale, Groupe Hospitalo-Universitaire Caremeau, Centre Hospitalier Universitaire Nîmes, Nîmes cedex 9, France (AM).

The authors have not disclosed any involvement in any organization with a direct financial interest in the

subject of the manuscript. Copyright © 2006 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins

DOI: 10.1097/01.CCM.0000233879.58720.87

Objectives: To describe the current practice of physicians, to report complications associated with endotracheal intubation (ETI)

performed in THE intensive care unit (ICU), and to isolate predictive factors of immediate life-threatening complications.

Design: Multiple-center observational study.

Setting: Seven intensive care units of two university hospitals. Patients: We evaluated 253 occurrences of ETI in 220 patients.

Interventions: From January 1 to June 30, 2003, data related to all ETI performed in ICU were collected. Information regarding

patient descriptors, procedures, and immediate complications were analyzed.

Measurements and Main Results: The main indications to intubate the trachea were acute respiratory failure, shock, and coma.

Some 148 ETIs (59%) were performed by residents. At least one severe complication occurred in 71 ETIs (28%): severe hypoxemia

(26%), hemodynamic collapse (25%), and cardiac arrest (2%). The other complications were difficult intubation (12%), cardiac arrhythmia

(10%), esophageal intubation (5%), and aspiration (2%). Presence of acute respiratory failure and the presence of shock as an

indication for ETI were identified as independent risk factors for occurrence of complications, and ETI performed by a junior physician

supervised by a senior (i.e., two operators) was identified as a protective factor for the occurrence of complications.

Conclusions: ETI in ICU patients is associated with a high rate of immediate and severe life-threatening complications. Independent

risk factors of complication occurrence were presence of acute respiratory failure and presence of shock as an indication

for ETI. Further studies should aim to better define protocols for intubation in critically ill patients to make this procedure safer.

(Crit Care Med 2006; 34:●●●–●●●)

Crit Care Med 2006 Vol. 34, No. 9 1

medicosurgical, two medical, and two surgical

units) that included a total of 85 beds. From

January 1 to June 30, 2003, data related to all

ETIs performed in these ICUs were collected

and analyzed. Intubations performed outside

of the ICU (in the operating room, in and

outside the hospital) were not studied. The

local ethics committee in human research of

Montpellier University Hospital approved this

observational study and stated that no informed

consent of the patient or next of kin

was required. No attempt was made to change

intubation practices during the course of the

study.

Definitions and Measurements

All data for each ETI were obtained by the

intubating physician or the supervisor and

verified by the investigators. For each ETI

performed in ICU, the following variables were

documented:

Patient Characteristics. We documented

age; gender; reason for admission to ICU; Simplified

Acute Physiology Score (SAPS) II (15)

on admission; status of the following within

the 60 mins before ETI: systolic blood pressure,

heart rate, the use of vasopressors, pulse

oximetry, the use of nasal oxygen therapy and

noninvasive ventilation; route of ETI (nasal or

oral); and status of the following in the 60

mins after ETI: systolic blood pressure, heart

rate, the use of vasopressor, pulse oximetry.

Clinical outcomes measured included the

number of days of mechanical ventilation, the

length of stay in ICU, and the vital status (dead

or alive).

Procedure Descriptors. We documented

time of the procedure: Daytime procedure was

defined as an ETI performed between Monday

and Friday from 8 am to 7 pm. Otherwise, time

of procedure was defined as on-call procedure.

We also documented the mean reason for ETI,

defined as acute respiratory failure (dyspnea

with arterial desaturation 90% and/or altered

mental state), shock (systolic blood pressure

90 mm Hg), cardiac arrest, or neurologic disorder

(Glasgow Coma Scale score 8). The

emergency characteristic of ETI was categorized

as follows: real emergency ETI required without

any delay, relative emergency ETI required

within 1 hr, and deferred emergency

ETI required in 1 hr; whether the patient was

informed about the ETI; and the physician involved

in the ETI. The medical staff included

residents training in anesthesiology (all had experience

in ETI in operating room 1 yr) and

skilled physicians (anesthesiologists and intensivists

with experience in ETI 5 yrs and experience

in ICU1 yr). We also recorded the use of

anesthesia and the anesthetic drugs used: Hypnotics

were separated into short-acting (thiopental,

etomidate, propofol) and long-acting

groups (hypnotics such as benzodiazepine) and

opioids (fentanyl, sufentanil, others). Neuromuscular

blocking drugs (NMBDs) were separated

into short-acting (succinylcholine) and longacting

NMBDs (pancuronium, vecuronium,

atracurium, and cis-atracurium). A rapid sequence

induction was defined as the administration

of a short-acting induction agent and

succinylcholine to achieve rapid loss of consciousness

and paralysis, the application of cricoid

pressure (Sellick maneuver), and securing

of the airway without insufflation to avoid regurgitation

(16).

Immediate Complications Associated With

ETI. Immediate complications occurring within

30 mins after ETI were divided into two categories

(1, 13, 17, 18): a) severe life-threatening

complications: cardiac arrest or death, severe

cardiovascular collapse defined as systolic

blood pressure 65 mm Hg recorded at least

one time and/or 90 mm Hg that lasted 30

mins despite 500–1000 mL of vascular loading

(crystalloids/or colloids solutions) and/or necessitating

introduction of vasoactive support,

or severe hypoxemia (decrease in oxygen saturation

by pulse oximetry to 80% during

attempts); mild to moderate complications:

difficult intubation (three or more attempts at

laryngoscopy to place the endotracheal tube

into the trachea and/or 10 mins using conventional

laryngoscopy and/or the need for

another operator) (1, 19), aspiration of gastric

contents, esophageal intubation, dental injury,

supraventricular and/or ventricular arrhythmia

(without loss of pulse), and dangerous

agitation.

Statistical Analysis

Continuous measurements are expressed in

mean SD. Patients who had ETI complications

were compared with those who did not have

complications. Categorical variables were compared

using Fisher’s exact test. Ordinal and continuous

variables were compared using the

Mann-Whitney test. For the observational study,

all procedures were included. However, to determine

predictors of an adverse outcome, only the

first ETI in ICU was considered; patients with

ETI due to cardiac arrest were excluded. Univariate

regression analysis was used to assess association

between the following risk factors and

the risk of ETI complications: age, gender, SAPS

II score, acute respiratory failure, coma, use of

NMBDs, use of etomidate, use of opioids, ETI

performed by junior, vascular loading (500,

500–1000, 1000 mL), lowest systolic blood

pressure, lowest pulse oxygen saturation, and

weaning failure. All prognostic variables that had

a p .20 determined by the univariate regression

were entered into a multivariate logistic

regression model. ETI as the dependent variable

and the models were performed by the means of

a stepwise backward procedure. Odds ratios are

presented with 95% confidence intervals. The

Hosmer and Lemeshow test was used to test the

goodness-of-fit. All reported p values are twotailed,

and a value .05 was considered statistically

significant. Statistical analyses were performed

using SAS/STAT software version 8.1

(SAS Institute, Cary, NC).

RESULTS

During the study period, 1,650 patients

were admitted in the 85 beds of the seven

ICUs. Two hundred and sixty-three ETIs

were performed during the study but ten

could not be analyzed because data were

missing and/or incomplete. Therefore, the

present study included 253 ETIs in 220

patients. The mean rate of intubated patients

in the seven ICUs was 74% (1,221 of

1,650). In fact, among the 1,221 intubated

patients, 263 intubations were performed

in the ICU (22%) and the others were performed

outside the ICU (operating room,

emergency department, prehospital setting).

Table 1 shows the comparison between

patients with life-threatening complications

related to ETI and those with no

life-threatening complications. Thirty-one

patients were intubated twice, two patients

three times, and one patient four times.

ETI Procedure Description

Among 253 ETIs, the main indications

for intubation were acute respiratory failure,

shock, and neurologic disorders (Table

1). The main characteristics of the procedure

are reported in Table 2. The hypnotic,

opioid, and neuromuscular drugs used are

shown in Table 3. ETIs were performed by

oral or nasal route in 246 and seven patients,

respectively. Seventy-five percent of

intubations were done on the first attempt,

13% required two attempts, 9% required

three attempts, and 3% required at least

four attempts.

ETI-Related Complications

The two categories of ETI complications

(severe life-threatening and mild to moderate

complications) are shown in Figure 1.

At least one severe complication occurred

in 71 ETI procedures (28%). Severe hemodynamic

collapse was observed in 65 of

them, and severe hypoxemia occurred in 66

ETI procedures. Cardiac arrest occurred in

four ETI (1.6%) procedures, and there were

two deaths at the time of or within 30 mins

after intubation; two other patients died at

day 2 and day 9. In 30 patients (12%), three

or more attempts were needed and/or the

intervention of another skilled operator

was required. Among these 30 patients with

difficult intubation, 12 developed severe hypoxemia

and seven had severe cardiovascular

collapse. The use of a fiberoptic laryngoscope

was required in two of the 30

patients. Among the 22 patients intubated

for shock, none had a difficult intubation.

2 Crit Care Med 2006 Vol. 34, No. 9

Cardiac arrhythmias occurred in 25

patients (10%). Esophageal intubations

occurred in 12 patients (4.6%) but were

always diagnosed with auscultation leading

to immediate reintubation without

any oxygen desaturation. The mean decreases

in the highest and lowest systolic

blood pressure values obtained before and

during or immediately after the ETI attempt

are presented in Figures 2 and 3.

The mean decreases in lowest pulse oxygen

saturation calculated between the

values before and during the procedure

for patients with complicated ETI and

those with no complication are presented

in Figure 4.

Risk Factors for Serious

ETI-Related Complication

The patients with severe ETI complications

were significantly older and had a

significantly higher SAPS II than those

with no ETI complications (Table 1).

They also had a significantly more precarious

hemodynamic status as evidenced

by shock being a more prevalent reason

for ICU admission, a lower systolic blood

pressure (Fig. 2), increased fluid loading

requirement, and vasopressor use. The

multivariate analysis (Table 4) showed

that the lower the systolic blood pressure

was before the intubation, the higher the

risk of having an ETI complication. The

other independent risk factor for ETI

complication was acute respiratory failure

as a reason for intubation. An ETI

attempt performed by a resident who was

always supervised by a senior (i.e., two

operators) was found to be the only protective

factor for the ETI complication

occurrence.

The main outcomes of the 220 included

ICU patients are shown in Table 5.

The patients who had serious complications

had a significantly higher mortality

rate than the patients who did not have

complications, but they also had a significantly

higher SAPS II score (Table 1). In

fact, the observed mortality rate was in

agreement with the predicted mortality

rate according to the SAPS II for each

group.

DISCUSSION

The main results of this study are that

ETI performed in ICU patients is associated

with a high rate of immediate and

severe life-threatening complications of

about 28% and that independent risk factors

of complications were presence of

acute respiratory failure and/or presence

shock as an indication for ETI. Moreover,

ETI performed by a junior physician supervised

by a senior (i.e., two operators)

was identified as a protective factor for

ETI complication occurrence. This is the

second prospective study to evaluate the

early complications of airway management

in critically ill adults, but it is the

first study to report the risk factors of ETI

complications with hemodynamic profiles

and it is the largest series reported

including 253 intubations performed in

220 ICU patients.

Table 1. Patient characteristics and reasons for intensive care unit (ICU) admission

Total

(n 253)

Complications

(n 71)

No Complications

(n 182) p Value

Age, yrs, mean (SD) 63 16 68 12 61 17 .001

Male gender, n (%) 180 (71) 44 (62) 136 (75) .04

SAPS II, mean (SD) 46 19 54 21 43 17 .001

Weight, kg, mean (SD) 73 18 74 19 73 18 NS

Height, cm, mean (SD) 169 8 169 8 169 9 NS

Type of admission, n (%)

Medical 203 (80) 56 (79) 147 (81) NS

Surgical 50 (20) 15 (21) 35 (19) NS

Reason for ICU admission, n (%)

Acute respiratory failure 134 (53) 34 (48) 100 (55) NS

Shock 33 (13) 18 (25) 15 (8) .02

Trauma 7 (3) 1 (1) 6 (3) NS

Postoperative 20 (8) 5 (7) 15 (8) NS

Cardiac arrest 3 (1) 2 (3) 1 (1) NS

Neurologic 34 (13) 5 (7) 29 (16) NS

Others 22 (9) 6 (9) 16 (9) NS

Reason for intubation, n (%)

Acute respiratory failure 159 (63) 33 (47) 126 (69) NS

Shock 22 (9) 15 (21) 7 (4) .03

Coma 33 (13) 10 (14) 23 (13) NS

Cardiac arrest 6 (3) 6 (9) 0 (0) NS

Replace the endotracheal tube 7 (3) 1 (1) 6 (3) NS

Unplanned extubation 7 (3) 1 (1) 6 (3) NS

Others 19 (8) 5 (7) 14 (8) NS

SAPS, Simplified Acute Physiology Score (15); NS, not significant.

Table 2. Operator status and main variables obtained before intubation

Total

(n 253)

Complications

(n 71)

No Complications

(n 182) p Value

Time, n (%)

Day 128 (51) 38 (54) 90 (49) NS

Night 125 (49) 33 (46) 92 (51) NS

Anesthesiology training, n (%) 171 (68) 51 (72) 120 (66) NS

Operator, n (%)

Senior 107 (42) 38 (54) 69 (38) .04

Junior 146 (58) 33 (46) 113 (62) .04

Informed patient, n (%) 129 (51) 34 (48) 95 (52) NS

Fluid loading, n (%) 109 (43) 43 (61) 66 (36) .001

500 mL 51 (20) 18 (25) 33 (18) NS

500–1000 mL 45 (18) 18 (25) 27 (14) 0.05

1000 mL 13 (5) 7 (10) 6 (3) 0.03

Lowest systolic blood

pressure, mm Hg, mean

(SD)

102 35 80 37 113 28 .001

Emergency characteristic of

ETI, n (%)

Real emergency 127 (50) 40 (56) 87 (48) NS

Relative emergency 97 (38) 25 (35) 72 (39) NS

Deferred emergency 29 (12) 6 (9) 23 (13) NS

Vasopressor use, n (%) 41 (16) 23 (32) 18 (10) .001

Noninvasive ventilation, n (%) 97 (38) 24 (34) 73 (40) NS

Nasogastric tube, n (%) 89 (35) 24 (34) 65 (36) NS

Glasgow Coma Scale score 11 4 10 4 11 4 NS

NS, not significant.

Crit Care Med 2006 Vol. 34, No. 9 3

ETI Practices

In this prospective multiple-center descriptive

study, 88% of the 253 ETIs were

performed in emergency or in relative

emergency conditions. Etomidate was the

most common hypnotic agent (50%) used,

and succinylcholine was the neuromuscular

blocker (69%) most used for this cohort

of patients (Table 3). Etomidate has become

the induction agent of choice in many institutions

because of its hemodynamic

safety profile (9, 20). The use of neuromuscular

blockers, especially nondepolarizing

agents, could lead to life-threatening hypoxia

when the trachea cannot be intubated;

these agents induce prolonged paralysis

with no spontaneous respiration. This explains

why succinylcholine was the most

commonly used neuromuscular blocker,

allowing the patient to breathe spontaneously

after 2–3 mins. Muscle relaxants were

used to facilitate 62% of all intubations in

our study, which was lower than the 80%

rate reported by Schwartz et al. (1) and

higher than the 22% rate reported by Le

Tacon et al. (2). The use of succinylcholine

in our study (69%) was more frequent than

that reported by Schwartz et al. (1) and Le

Tacon et al. (2), who reported usage rates of

57% and 41%, respectively. These differences

in anesthetic agents use and more

particularly neuromuscular blocker use

among different studies can be explained in

part by the lack of randomized controlled

studies comparing different protocols to

manage tracheal intubation in the ICU, as

well as the lack of exhaustive recommendations

for airway management in critically

ill patients contrary to patients anesthetized

in the operating room for surgery

(19).

Immediate Complications

Associated With ETI and Risk

Factors

Complications occurred in nearly half

of the patients, and serious complications

occurred in 28%. The most frequent of

them were hypotension leading to a frequent

use of vasopressor and severe hypoxemia,

which occurred with a similar

incidence (Fig. 1). The complications of

ETI did not differ by location or time of

day of the procedure (Table 2) as reported

by Schwartz et al. (1). After a multivariate

analysis, hypotension and acute respiratory

failure were independent risk factors

for complications, whereas an ETI performed

by a junior supervised by senior

physician was a protective factor. This fact

can be surprising, but all the ETI procedures

performed by the junior were supervised

by a senior, which could mean that

for each ETI, the presence of at least two

operators improved the conditions of the

procedure. In other words, a second pair of

hands is often useful in helping to manage

a difficult situation. In fact, the two main

risk factors for immediate complications

after tracheal intubation are precisely the

two main indications for tracheal intubation.

In other words, if tracheal intubation

is justified because of shock or acute respiratory

failure, tracheal intubation may result

in severe hemodynamic collapse or severe

hypoxemia. In these cases, it is difficult

to clearly differentiate the cause from the

effect.

The incidence of difficult intubation in

the present study was 12%. This percentage

is similar to that reported by Schwartz et al.

(8%) (1) but remains lower than those reported

in the Le Tacon study of 22% (2).

Although 67% of physicians and residents

involved in the present study were anesthesiologists,

there was no difference in diffi-

Table 3. Incidence of use of each anesthetic drug for endotracheal intubation

Total

(n 253)

Complications

(n 71)

No Complications

(n 182) p Value

Anesthetic drugs used, n (%) 229 (91) 61 (86) 168 (92) NS

Rapid sequence induction, n (%) 92 (36) 26 (37) 66 (36) NS

Hypnotic, n (%)

Thiopental 23 (9) 5 (7) 18 (10) NS

Propofol 36 (14) 5 (7) 31 (17) NS

Etomidate 126 (50) 33 (46) 93 (51) NS

Others 44 (17) 18 (25) 26 (14) NS

Opioids, n (%) 66 (30) 22 (31) 44 (24) NS

Fentanyl 27 (41) 7 (32) 20 (45) NS

Sufentanyl 12 (18) 6 (27) 6 (14) NS

Others 27 (41) 9 (41) 18 (41) NS

Neuromuscular blocking drugs,

n (%)

156 (62) 35 (49) 121 (67) .04

Succinylcholine 108 (69) 20 (57) 88 (73) NS

Others 48 (31) 15 (43) 33 (27) NS

0%

5%

10%

15%

20%

25%

30%

Severe hypoxemia

Severe collapse

Cardiacarrest

Death

Difficult intubation

Cardiacarrhythmia

Esophgeal intubation

Agitation

Aspiration

Dental injury

Figure 1. Incidence of the two categories of endotracheal intubation complications in the whole group:

severe complications (serious hypoxemia, severe collapses, cardiac arrest and death) and mild to

moderate complications (difficult intubation, cardiac arrhythmia, esophageal intubation, agitation,

aspiration and dental injury). Mortality rate is calculated based on the 247 intubations carried out for

patients with an obtainable blood pressure at the time of procedure.

4 Crit Care Med 2006 Vol. 34, No. 9

cult intubations between anesthesiologists

and nonanesthesiologists. Therefore, most

of the operators could be considered experienced

in this procedure. The lack of statistically

significant differences in complication

rates between anesthesiologists and

nonanesthesiologist physicians shows that

appropriately trained and experienced nonanesthetist

physicians in the ICU have a

similar high level of airway management

patient safety compared with anesthesiologists.

As reported by Schwartz et al. (1),

multiple attempts were not associated with

adverse outcomes such as seizures or cardiac

arrest.

Rapid sequence induction with Sellick’s

technique was applied in 36% of ETIs and

was not significantly different between the

complicated and noncomplicated ETI patients,

whereas it is recommended in emergency

conditions and/or in patients with

a full stomach (19). This technique is

strongly recommended for emergency anesthesia

and is probably unknown among

nonanesthesiologists. However, even when

this technique was applied, aspiration was

not always avoided (5).

In our study, we defined cardiac arrest

and mortality associated with intubation

if they occurred during or within 30 mins

of the procedure. During 247 intubations

performed in 214 patients for reasons other

than cardiac arrest, four patients developed

cardiac arrest (1.6%) and two (0.8%) met

the definition of intubation-associated

mortality. The two other patients died at

day 2 and day 9. The rate of death in the

Schwartz study (1) was 3% and was

higher than in the present study. However,

these authors reported all intubations

including those performed outside

the ICU.

One of the most critical determinations

during noninvasive ventilation is when intubation

is necessary. It is possible that a

delay in intubation was a cause for the

significant increase in the risk of death in

patients treated by noninvasive ventilation

reported in clinical trials, through a number

of mechanisms such as cardiac ischemia,

increased respiratory muscle fatigue,

aspiration pneumonitis, and complications

of emergency intubation (21–23). The high

rates of serious complications obtained in

our study for severe collapse (25%) and severe

hypoxemia (26%) were surprising, although

we used a very strict definition for

this complication even if it occurred transiently.

However, these rates were reported

for the first time, because no previous study

documented these complications.

Limitations

Our study has some limitations. The

data were self-reported by the persons who

performed the ETI, so the degree of intubation

difficulty may have been underestimated

or overestimated to be consistent

with the results. This study is purely a descriptive

report of the ETI practices in ICU.

Because patients were not randomly assigned

to different methods of intubation,

Lowest systolic blood pressure

0

30

60

90

120

150

180

before ETI during ETI

mmHg

complications no complications

Highest systolic blood pressure

0

30

60

90

120

150

180

before ETI during ETI

mmHg

complications no complications

* ** * **

Figure 2. Evolution of lowest and highest systolic blood pressures recorded before and during 253 endotracheal intubation (ETI) procedures obtained for

the 71 patients who had severe complications (complications) and the 182 patients who did not have severe complications (no complications). The lowest

and highest systolic blood pressures were those recorded within the 10 mins before and after ETI procedure. *p .05; **p .01 (p values pertain to

differences between complication group and noncomplication group).

-50

-40

-30

-20

-10

0

Decrease in

lowest SBP

Decrease in

Highest SBP

%

complications no complications

** **

Figure 3. Variation between the lowest and the highest systolic blood pressures (SBP) obtained before and

during the endotracheal intubation procedures obtained for the 71 attempts with severe complications

(complications) and the 182 attempts with no severe complications (no complications). **p .01.

Crit Care Med 2006 Vol. 34, No. 9 5

the success rates and rates of immediate

complications for the different methods

must be interpreted with caution. Because

the observed complications may be due to

the severity of illness of the patient, we

chose very “extreme” definitions of collapse

due to ETI and severe hypoxemia. Indeed,

the patients who had hemodynamic instability

before ETI developed severe hypoxemia

more often and patients who had been

intubated for respiratory distress developed

a collapse more often after ETI. Another

limitation is that we did not record the dose

of total administered drugs used for ETI,

and we cannot evaluate the correlation

with the degree of hypotension occurring

after the attempt. However, among the 22

patients intubated for shock, none had a

difficult intubation, which implies that in

these patients the dose of administered drugs

did not influence intubation conditions.

CONCLUSION

This prospective multiple-center study

of 253 endotracheal intubations performed

in ICU showed a high frequency of serious

life-threatening complications (28%) including

severe hypotension (26%), severe

hypoxemia (25%), cardiac arrest (1.6%),

and death (0.8%). Presence of acute respiratory

failure and presence of shock as an

indication for ETI were identified as independent

risk factors of complication occurrence.

Moreover, ETI performed by a junior

physician supervised by a senior (i.e., two

operators) was identified as a protective effect

of ETI complication occurrence. Further

studies should aim to better define

protocols (drugs, dosage, rapid sequence

induction, systematic loading) for endotracheal

intubation in critically ill patients to

make this procedure safer.

ACKNOWLEDGMENTS

We thank all the nurses and doctors of

all the units who contributed to this effort.

We are grateful to Pr. Frédéric Adnet

and Pr. Peter Dodek for very useful comments.

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NS

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Table 4. Multivariate logistic regression analysis to assess independent risk factors for development

of endotracheal intubation (ETI) complications

Predictive Risk

Factor Odds Ratio

95% Confidence

Interval

Acute respiratory failure 3.04 1.08 8.75

Lowest systolic blood pressure 0.98 0.98 0.99

Junior operator 0.42 0.22 0.78

The 247 ETI attempts obtained in 214 patients were included for analysis. The six patients

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Total

(n 220)

Complications

(n 59)

Control

(n 161) p Value

Duration of mechanical ventilation,

days, mean (SD)

10.6 14.3 10.5 12.6 10.6 15.1 NS

ICU length of stay, days, mean (SD) 19.3 18.7 17.8 18.5 19.8 18.9 NS

ICU mortality rate, % 46 61 31 .001

6 Crit Care Med 2006 Vol. 34, No. 9

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Crit Care Med 2006 Vol. 34, No. 9

[Ace844]

(Annals of Emergency medicine Volume 47 @ Issue 6, Pages 532-541 (June 2006)

Out-of-Hospital Endotracheal Intubation: Where Are We?

Henry E. Wang, MD, MPH, Donald M. Yealy, MD

Received 27 October 2005; received in revised form 9 January 2006; accepted 11 January 2006 published online 27 February 2006.)

While remaining prominent in paramedic care and beneficial to some patients, out-of-hospital endotracheal intubation has not clearly improved survival or reduced morbidity from critical illness or injury when studied more broadly. Recent studies identify equivocal or unfavorable clinical effects, adverse events and errors, interaction with other important resuscitation interventions, and challenges in providing and maintaining procedural skill. We provide an overview of current data evaluating the overall effectiveness, safety, and feasibility of paramedic out-of-hospital endotracheal intubation. These studies highlight our limited understanding of out-of-hospital endotracheal intubation and the need for new strategies to improve airway support in the out-of-hospital setting.

Introduction

Paramedic out-of-hospital endotracheal intubation originated in the 1970s from efforts to improve outcomes from cardiac arrest and major trauma.1, 2, 3, 4, 5 At that time, the best available methods for paramedic out-of-hospital airway management and ventilation were bag-valve-mask ventilation and the esophageal obturator airway.6, 7, 8, 9 Bag-valve-mask performance was perceived to be inadequate, and esophageal obturator airway use resulted in many complications, including inadequate or delayed ventilation, aspiration, pharyngeal and esophageal injury, gastric rupture, tracheal occlusion, and inadvertent tracheal intubation.6, 8, 10, 11, 12, 13, 14, 15 Out-of-hospital endotracheal intubation offered an alternative method to optimize care, promising superior airway protection, efficient ventilation, and a route to deliver endobronchial medications.16 Endotracheal intubation was also the standard for in-hospital resuscitation, classified as a “definitely helpful” intervention by then-current Advanced Cardiac Life Support guidelines.17 Several authors reported groundbreaking efforts to implement out-of-hospital endotracheal intubation in Boston, Columbus, San Diego, and Pittsburgh.1, 2, 3, 4

SEE EDITORIAL, P 542.

Despite its accepted role in clinical practice for more than 25 years, a growing body of literature suggests that out-of-hospital endotracheal intubation is not achieving its intended overarching goals. In selected cases, the intervention may cause harm. In this article, we provide an overview of recent data evaluating the effectiveness, safety, and feasibility of paramedic out-of-hospital endotracheal intubation.

Is Out-of-Hospital Endotracheal Intubation Effective?

The fundamental test of a medical intervention is whether it improves the outcome of the targeted patients.18 In this light, the overarching goal of out-of-hospital endotracheal intubation is to reduce mortality and morbidity for those in need of airway support. Several investigators have evaluated survival and neurologic outcome after out-of-hospital endotracheal intubation19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 (Table). These studies largely involve retrospective analyses of predominantly injured patients. Although 2 studies identified increased survival from out-of-hospital endotracheal intubation, the remaining efforts found either decreased or no effect on survival. No studies have identified improved neurologic outcome from out-of-hospital endotracheal intubation.

Table. Studies evaluating survival or neurologic outcome after out-of-hospital endotracheal intubation.⁎

Study Design Primary Population Primary Comparison (Group Sizes) Primary Finding

Bochicchio et al, 200329 Prospective observational; single trauma center (Baltimore); univariable/stratified Severe TBI; ETI in field or ED OOH-ETI (78) vs ED-ETI (113) Higher mortality (OR 2.1; 95% CI 0.9–5.0)†‡ in OOH-ETI group

Bulger et al, 200519 Retrospective; single trauma center (Seattle); multivariable adjusted Severe TBI; RSI or ETI in field OOH-RSI (775) vs OOH-ETI (302) Higher mortality (OR 1.6; 95% CI 1.0–2.4) and poorer neurologic outcome (1.7; 1.2–2.6) in OOH-ETI group

Christensen and Hoyer, 200330 Retrospective; single mobile emergency unit with anesthetist (Denmark) All trauma; ETI in field with and without drugs OOH-ETI with (62) vs without (12) drugs Higher mortality (OR 15.2; 95% CI 1.9–673.2)† for OOH-ETI without drugs

Cooper et al, 200131 Retrospective; National Pediatric Trauma Registry; univariable Severe pediatric TBI OOH-ETI (479) vs OOH-BVM (99) No difference in mortality (OR 1.0; 95% CI 0.6-1.6)†

Davis et al, 200320 Prospective interventional series, historical controls; countywide (San Diego); multivariable adjusted Severe TBI; RSI in field vs non-ETI historical controls OOH-RSI (209) vs non-OOH-ETI (627) Higher mortality (OR 1.6; 95% CI 1.1–2.2) and poorer neurologic outcome (1.6; 1.2–2.3) in OOH-RSI group

Davis et al, 200521 Retrospective; countywide trauma registry (San Diego) multivariable adjusted Severe TBI; ETI in field or ED OOH-ETI (2,665) vs ED-ETI (2,220) Higher mortality (OR 2.1; 95% CI 1.8–2.5)† in OOH-ETI group

DiRusso et al, 200532 Retrospective; National Pediatric Trauma Registry; multivariable adjusted All pediatric trauma OOH-ETI (1,928) vs non–trauma center ETI (1,647), trauma center ETI (1,874) and non-ETI (44,739) Higher mortality for OOH-ETI vs non–trauma center ETI (OR 3.2; 95% CI 2.7–3.7)†§; vs trauma center ETI (4.1; 3.5–4.8)†§; vs non-ETI (142.0; 119.6–168.5)†§ Poorer neurologic outcome for OOH-ETI vs non–trauma center or trauma center ETI∥

Gausche et al, 200022 Prospective controlled (pseudorandomized) interventional trial; countywide (Los Angeles) Pediatrics; ETI or BVM in field OOH-ETI/BVM (420) vs OOH-BVM (410) No difference in mortality (OR 0.8; 95% CI 0.6–1.1) or neurologic outcome (0.9; 0.6–1.2)

Lockey et al, 200123 Retrospective; single air medical service (Great Britain); descriptive All trauma; ETI in field without drugs Mortality of OOH-ETI without drugs (486) Low (0.2%) survival

Murray et al, 200024 Retrospective; countywide trauma registry (Los Angeles); multivariable matched/adjusted Severe TBI OOH-ETI (57) vs non-OOH-ETI (57) Higher mortality (OR 4.2; 95% CI 2.1–8.9) in OOH-ETI group

Sloane et al, 200025 Retrospective; single trauma center (San Diego); univariable Severe TBI; RSI in field or ED OOH-RSI (47) vs ED-RSI (267) No difference in mortality (OR 0.6; 95% CI 0.1–2.6)† or neurologic outcome (1.1; 0.3–3.8)†

Stockinger et al, 200426 Retrospective; single trauma center (New Orleans); univariable/stratified All trauma; ETI or BVM in field OOH-ETI (316) vs OOH-BVM (217) Higher mortality (OR 18.0; 95% CI 11.2–29.1)† in OOH-ETI group

Suominen et al, 200033 Retrospective; single trauma center (Finland); univariable Severe pediatric TBI OOH-ETI (24) vs non–trauma center ETI (13) vs trauma center ETI (22) Lower mortality for OOH-ETI vs non–trauma center ETI (OR 0.1; 95% CI 0.002–1.1)†‡; no difference vs trauma center ETI (3.7; 0.9–15.8)†

Wang et al, 200427 Retrospective; statewide trauma registry (Pennsylvania); multivariable and propensity-score adjusted Severe TBI; ETI in field or ED OOH-ETI (1,797) vs ED-ETI (2,301) Higher mortality (OR 4.0, 95% CI 3.2–4.9), poorer neurologic outcome (1.6; 1.2–2.3), and poorer functional outcome (severe impairment 1.9; 1.3–2.5) in OOH-ETI group

Winchell and Hoyt, 199728 Retrospective; countywide trauma registry (San Diego); univariable/stratified Blunt trauma, GCS score ≤8 OOH-ETI (527) vs non–OOH-ETI (565) Lower mortality (OR 0.6; 95% CI 0.5–0.8)† in OOH-ETI group; no difference in neurologic outcome (1.4; 1.0–1.9)†

BVM, Bag-valve-mask ventilation; ETI, endotracheal intubation; GCS, Glasgow Coma Scale; OOH, out-of-hospital; RSI, rapid sequence intubation; TBI, traumatic brain injury.

⁎

Only the primary findings (survival and neurologic outcome) are summarized; results of other outcomes and subgroup analyses are not presented.

†

Odds ratio calculated from published results.

‡

Author stated significant at P<.05.

§

Calculated univariable odds ratios; multivariable adjusted figures not published.

∥

Odds ratios could not be calculated from published results.

Of these out-of-hospital endotracheal intubation studies, the most notable effort is by Gausche et al.22 In this prospective trial, 830 critically ill pediatric out-of-hospital patients in Los Angeles County received either bag-valve-mask ventilation or bag-valve-mask followed by out-of-hospital endotracheal intubation. The authors found that an airway strategy incorporating out-of-hospital endotracheal intubation offered no survival or neurologic benefit over bag-valve-mask ventilation alone. Although limited by its patient population (primarily pediatric patients in a large urban location), this seminal effort represents the largest prospective, controlled evaluation of out-of-hospital airway management interventions.

The San Diego Rapid Sequence Intubation Trial tested the large-scale implementation of rapid sequence intubation performed by ground-based paramedic units.20 In this outcomes analysis, 209 traumatic brain injury patients receiving out-of-hospital rapid sequence intubation (neuromuscular blockade–assisted endotracheal intubation) were matched to 627 historical nonintubated controls, facilitating a comparison of out-of-hospital rapid sequence intubation with the alternative of no out-of-hospital endotracheal intubation at all. The authors observed higher mortality in patients receiving out-of-hospital rapid sequence intubation (odds ratio 1.6; 95% confidence interval [CI] 1.1 to 2.2). This study is notable because of its large-scale evaluation of one of the most advanced airway management techniques.

In the evaluation of this series of studies (listed in the Table and discussed above), several important observations arise about their methods, designs, and limitations. Most of these efforts used retrospective designs involving a single-center or countywide trauma registry and included primarily injured or head-injured patients.19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 The Gausche study is the only effort using a prospective, controlled design in medical (nontrauma) cases.22 The studies noted in the Table evaluated survival to hospital discharge only; they did not study long-term outcomes and often inferred neurologic outcome from discharge destination (ie, discharge to home, rehabilitation center, psychiatric facility, or jail = “good neurologic outcome”; discharge to nursing home or other extended care facility = “poor” neurologic outcome). None used formal neurologic or functional measures such as the Glasgow Outcome Scale or the Functional Independence Measure.34, 35

Risk adjustment is important in retrospective analyses because many confounding factors can lead to adverse outcome, not just the manner of airway management.36 However, only some authors used multivariable adjustment to account for these variations.19, 20, 21, 24, 27, 32 Several studies using univariable analysis (including the 2 efforts identifying a survival benefit for out-of-hospital endotracheal intubation) may not have adequately accounted for confounders.28, 33 For example, Winchell and Hoyt28 analyzed 1,098 head-injured patients and found that out-of-hospital endotracheal intubation increased survival by 21%, but this effort did not adjust for severity of injury or illness. Suominen et al33 evaluated 59 pediatric traumatic brain injury patients and found that out-of-hospital endotracheal intubation resulted in a 34% increase in survival over patients intubated in the emergency department (ED) of a referring hospital; however, this small effort similarly did not adjust for severity of injury or illness.

The comparison (exposure) groups in these studies differ, each posing a different scientific question. For example, the Davis et al,20 Murray et al,24 and Winchell and Hoyt28 studies used controls that did not receive out-of-hospital endotracheal intubation; we do not know whether these individuals later received ED endotracheal intubation or no endotracheal intubation at all. In our analysis of intubated traumatic brain injury patients in Pennsylvania, we excluded patients not receiving endotracheal intubation in either the out-of-hospital or ED setting, hence facilitating a comparison of endotracheal intubation during the acute out-of-hospital or ED phases only.27 In contrast, the Bulger et al19 study compared out-of-hospital conventional and rapid sequence endotracheal intubation techniques, excluding patients not intubated in the out-of-hospital setting. This latter study compares different out-of-hospital endotracheal intubation techniques, not out-of-hospital endotracheal intubation versus non-out-of-hospital endotracheal intubation.

In summary, few studies have demonstrated benefit from out-of-hospital endotracheal intubation.28, 33 Most showed an adverse or no effect on outcome.20, 21, 22, 24, 26, 27, 29, 31, 32 These observations contradict the assumption that aggressive airway intervention is associated with improved resuscitation outcomes. Larger studies with prospective designs may be instrumental in revealing an undetected benefit. However, an important alternate reaction is to recognize that multiple studies arrived at similar conclusions and identified substantial effect sizes, despite their differing populations, disease groups, designs, and limitations. If not directly causative, out-of-hospital endotracheal intubation may have close parallel relationships with factors leading to adverse outcome. A logical direction is to better identify the underlying relationships.

Is Out-of-Hospital Endotracheal Intubation Safe?

Therapeutic “safety” refers to freedom from accidental injury during the course of medical care.37 Adverse events and errors may contribute to the poor outcomes associated with out-of-hospital endotracheal intubation. This relationship is plausible, given that out-of-hospital endotracheal intubation is a complex procedure with many potential pitfalls, including key errors (eg, unrecognized esophageal tube placement) that can result in morbidity or death. Errors may be more likely in the uncontrolled out-of-hospital environment than in other settings.38 Several recent efforts highlight the underrecognition of out-of-hospital endotracheal intubation errors.

Katz and Falk39 evaluated 108 paramedic endotracheal intubation patients arriving at a regional trauma center in Florida. The authors used a systematic physician approach to confirm proper tube placement on ED arrival, including the selected use of direct revisualization. The authors found that more than 25% of the endotracheal tubes were misplaced, two thirds of these in the esophagus. The authors partially attributed the results to noncompliance with out-of-hospital protocols requiring placement confirmation using carbon dioxide detection. Jemmett et al40 conducted a similar study of 109 paramedic endotracheal intubation patients in Maine (an emergency medical services [EMS] system with no carbon dioxide detection protocol) and found a similar tube misplacement rate of 12%. Jones et al41 reported a lower (5.8%) tube misplacement rate for 208 paramedic endotracheal intubation in Indianapolis, but this study occurred in a region serviced primarily by a single EMS agency with close medical oversight.

Dunford et al42 examined a subset from the San Diego Rapid Sequence Intubation Trial, finding that accidental oxygen desaturation (SaO2 <90%) occurred in 31 of 54 (57%) patients and marked bradycardia (pulse rate <50 beats/min) in 6 of 54 (19%) patients. Moreover, in 84% of these adverse events, the paramedic described the intubation effort as “easy.” Ehrlich et al43 compared field (out-of-hospital), referring hospital and trauma center endotracheal intubation of pediatric trauma patients. Complications (esophageal intubation, mainstem intubation, aspiration, barotrauma, incorrect tube size, tube dislodgment) occurred in two thirds of the 59 out-of-hospital endotracheal intubations.

Self-reporting methods are often used to identify medical errors in the in-hospital setting.37 In the Gausche et al22 study, of 186 initially successful endotracheal intubations, paramedics reported unrecognized esophageal intubation in 2%, tube dislodgment in 14%, and mainstem intubation in 18%. In a prospective multicenter effort involving 45 EMS services, we demonstrated the feasibility of using anonymous, structured, closed-form, self-reporting forms to identify out-of-hospital endotracheal intubation errors.44 Of 1,953 endotracheal intubations, tube misplacement (esophageal, delayed recognition or unrecognized, or dislodgment) was reported in 61 (3.1%) intubations, multiple endotracheal intubation attempts (4 or more laryngoscopies) occurred in 62 (3.2%) intubations, and endotracheal intubation efforts failed in 359 (18.5%) intubations. More than 22% of patients experienced 1 or more of these errors or complications. Although these data are limited by self-reporting biases and a moderate return rate (68%), they still identify worrisome “best case” error rate estimates; that is, true error rates are likely to be higher, not lower, than reported with this design.

These data highlight our incomplete awareness of and limited ability to identify out-of-hospital endotracheal intubation errors. For example, the Katz and Falk study highlighted that out-of-hospital endotracheal intubation is prone to detection bias; errors go undetected unless systematically identified.39 Cases series describing tracheal and pulmonary injury from out-of-hospital endotracheal intubation indicate that many errors are identified only through invasive tests or autopsy.45, 46 Dunford et al42 showed that during the course of routine care, rescuers are often unaware of adverse events, even when equipped with the most advanced monitoring techniques. Although none of these efforts formally linked out-of-hospital endotracheal intubation errors to outcome, these events have plausible connections with patient outcome. These studies highlight our underrecognition and incomplete understanding of the range of errors occurring during out-of-hospital endotracheal intubation.

Does Out-of-Hospital Endotracheal Intubation Affect Other Aspects of Care?

Current paramedic textbooks portray endotracheal intubation as a procedure to be completed independent of other patient care tasks.47 However, other interventions often occur concurrently with endotracheal intubation; for example, chest compressions, electrical therapy, intravenous access, or the administration of drugs. An important recent realization is that out-of-hospital endotracheal intubation may influence patient outcome by interacting with or affecting the execution of these simultaneous therapies. These observations have occurred in several disease groups. For example, after successful out-of-hospital endotracheal intubation, rescuers commonly perform ventilation manually (without the assistance of portable ventilators) using tactile feedback only. Consequently, out-of-hospital endotracheal intubation may result in unintended hyperventilation, which may be deleterious in certain conditions. In porcine models of hemorrhagic shock, Pepe et al 48, 49 found that increased respiratory rates (20 and 30 breaths/min) resulted in decreased systolic blood pressure and cardiac output, respectively. Davis et al50 showed that hyperventilation occurs frequently after out-of-hospital rapid-sequence intubation for traumatic brain injury, a condition in which hyperventilation can reduce cerebral perfusion. The investigators noted an association between hyperventilation and increased mortality.51

Aufderheide and Lurie52 and Aufderheide et al53 identified the same hyperventilation phenomenon in intubated cardiac arrest patients. Using physician responders to monitor out-of-hospital cardiac arrest victims, the authors also found that accidental hyperventilation raised intrathoracic pressure during chest compressions, thereby impeding coronary perfusion pressure, an important element for successful resuscitation.54 They observed that these episodes occurred despite the specific training of the paramedics in this study.

Experts believe that control of intracranial pressure is important in the treatment of traumatic brain injury.50, 55, 56, 57 Physicians often use rapid sequence intubation to attenuate intracranial pressure response to the stress of endotracheal intubation.56 The aim to control intracranial pressure led to the proposal to replace nasotracheal intubation with rapid sequence intubation in these patients. However, the San Diego Rapid Sequence Intubation Trial found that adverse events such as inadvertent hyperventilation, oxygen desaturation, bradycardia, and increased mortality occurred with rapid sequence intubation approaches.20, 42, 51 Thus, efforts to precisely control one aspect of physiology during airway management disturbed other body systems.

Although meriting additional study, these findings in different disease states suggest that unanticipated physiologic effects may offset the potential benefits of proper endotracheal intubation. These observations underscore our poor understanding of how current field airway management, oxygenation, ventilation, and other physiologic processes interact during the resuscitation of different disease states.

How Do Paramedics Learn and Maintain Intubation Skills?

Because the manner of intubation may affect patient outcome, a logical area of concern involves paramedic acquisition and maintenance of out-of-hospital endotracheal intubation skill. For example, in the Gausche et al22 study, paramedics did not perform pediatric out-of-hospital endotracheal intubation before the trial. In the San Diego Rapid Sequence Intubation Trial, paramedics received a 7-hour didactic session without supplemental live training.58 These factors may have reduced the potential benefit of out-of-hospital endotracheal intubation.

Endotracheal intubation is a complex procedure, arguably more difficult when attempted in the uncontrolled out-of-hospital setting. Unlike physicians working in protected, stable, and well-illuminated settings (such as the operating room and ED), paramedics often attempt endotracheal intubation in awkward situations; for example, on the floor, in cramped rooms, or in the twisted metal of a motor vehicle.59, 60 Out-of-hospital patients are critically ill and often severely injured, and most would be considered “difficult” or high-risk intubations by in-hospital anesthesia standards.61 Given these challenges, one would expect paramedics to acquire and maintain endotracheal intubation skills well above minimum levels. However, paramedic endotracheal intubation training and clinical experience are relatively limited.

For example, there is significant disparity between consensus procedural standards for paramedic students and other endotracheal intubation providers. The national paramedic curriculum requires students to perform 5 successful endotracheal intubations to graduate.62 In contrast, emergency medicine residents, anesthesiology residents, and nurse anesthetist trainees are expected to perform between 35 and 200 endotracheal intubations before graduating from their respective training programs.63, 64, 65, 66, 67, 68

Using data on 7,635 endotracheal intubations attempted by 802 paramedic trainees from 60 training programs, we found that across all clinical settings (operating room, field, ED, other in-hospital), paramedic students attempted a median of 7 endotracheal intubation (interquartile range 4-12).69 Using multivariable modeling, we predicted that paramedic students in this cohort required 15 to 20 endotracheal intubation encounters to attain baseline “proficiency” (predicted endotracheal intubation success threshold of 90%). Similar modeling efforts using cohorts of medical students, paramedic students, and anesthesia residents have identified even higher thresholds for attaining proficiency.63, 66, 70, 71 These observations suggest that the ideal level of baseline endotracheal intubation experience is much higher than the current national standard of 5 endotracheal intubations.62

Endotracheal intubation training in the controlled operating room setting is ideal, but according to these figures, the number of operating room cases needed to train paramedic students is formidable, approximately 80,000 operating room cases nationally each year (approximately 200 accredited paramedic training programs times approximately 20 graduating students/program/year times 20 endotracheal intubations/student/year=80,000 intubations/year).69 This estimate does not include students in nonaccredited paramedic programs or paramedics already in clinical practice. Furthermore, although increasing opportunities for operating room endotracheal intubation training is desired, paramedic training programs nationally have observed a general reduction in these opportunities, a phenomenon attributed to competition with other students, the widespread use of nonintubation techniques (such as the laryngeal mask airway), and anesthesiologists’ medicolegal concerns.72

Mannequins and human simulators provide opportunities for paramedic endotracheal intubation training, but only 1 study has evaluated how these platforms translate to clinical skill. In an effort occurring more than 20 years ago, Stewart et al2 assigned paramedics to different training strategies, including combinations of mannequin, animal, and operating room endotracheal intubation. Although the authors indicated no difference in clinical endotracheal intubation success rates between the groups on limited multivariable analysis, the unadjusted data suggested higher initial and ongoing endotracheal intubation success in the operating room–trained groups. A more recent effort by Hall et al73 compared paramedic operating room training with human simulator training. Although the authors stated equivalence between the 2 modalities, the evaluated outcome was operating room endotracheal intubation performance, not clinical out-of-hospital endotracheal intubation performance.

Cadavers (ie, recently dead patients) have also been used for paramedic endotracheal intubation training, but only 1 study has evaluated the connection with clinical performance. Stratton et al74 compared mannequin with mannequin+cadaver training and found no difference in clinical endotracheal intubation performance between these groups. However, this inference was based on 60 paramedics, each performing a mean of only 3 endotracheal intubations. There are no direct comparisons of cadaver and operating room–based training. Cadavers were once widely used for teaching paramedic endotracheal intubation, but recent ethical concerns have curtailed learning opportunities on the recently dead.75, 76

Beyond baseline proficiency, regular clinical experience is likely an important element for maintaining endotracheal intubation skill. Studies of complex medical procedures (such as cardiac catheterization and bypass) suggest that centers and practitioners who perform these interventions frequently have improved survival and lower complication rates.77, 78, 79, 80 In Maine, Burton et al81 found that only 40% of paramedics attempted out-of-hospital endotracheal intubation annually, and only 1% to 2% of all paramedics performed 5 or more out-of-hospital endotracheal intubations annually. Separate from that study, we used 2003 statewide data from Pennsylvania, tallying the number of out-of-hospital endotracheal intubations performed by certified advanced life support rescuers (paramedics, out-of-hospital nurses, EMS physicians).82 We found that rescuers performed a median of only 1 out-of-hospital endotracheal intubation (interquartile range 0 to 3) during the study period; 39% performed no out-of-hospital endotracheal intubations, and 67% performed fewer than 2 out-of-hospital endotracheal intubations. Thus, contrary to common assumptions, most individual paramedics performed the procedure infrequently. Although the exact numbers needed to maintain out-of-hospital endotracheal intubation skill are unknown, these procedural frequency figures seem relatively low.

The original models of out-of-hospital endotracheal intubations in Boston, Columbus, San Diego, and Pittsburgh were designed for small, closely supervised, highly skilled cadres of paramedics working in busy urban EMS systems and supported by intensive training.1, 2, 3, 4 Today, although many individual paramedics demonstrate exceptional endotracheal intubation skill, one must reconsider whether all paramedics nationally can attain the same level of excellence, given current limits in endotracheal intubation training and clinical experience.

Can We Improve Out-of-Hospital Endotracheal Intubation?

The current literature draws attention to many problematic aspects of out-of-hospital endotracheal intubation while offering few affirmations of current practice. Proposed solutions address only isolated aspects of the procedure, and none provide perfect or complete answers. For example, some have proposed that systematic use of waveform capnography could eliminate endotracheal tube misplacements in the out-of-hospital setting.39, 83, 84 Silvestri et al83 recently reviewed 213 out-of-hospital endotracheal intubations arriving at a Florida Level I trauma center. The authors found that the tube misplacement rate was zero percent when waveform capnography was used and 23.3% when waveform capnography was not used. However, only limited formal data describe the accuracy of these devices on cardiac arrests, which comprise most of the endotracheal intubations in the out-of-hospital setting.83, 85, 86, 87

Some directors have expanded the use of sedative or neuromuscular blocking agents to improve the out-of-hospital endotracheal intubation success of nonarrest patients.88 However, as discussed previously, the San Diego Rapid-Sequence Intubation Trial showed that important complications may result when these advanced techniques are introduced on a large-scale basis.20, 42 Because of its profound sedative effects and stable hemodynamic profile, some EMS systems have used etomidate alone (without neuromuscular blockade) to facilitate out-of-hospital endotracheal intubation of nonarrest patients.89, 90 However, a recent randomized controlled trial comparing etomidate-only with midazolam-only facilitated cases found no difference in out-of-hospital endotracheal intubation success rates.91 The observed etomidate endotracheal intubation success rate in this trial was 76% (95% CI 65% to 87%), which may be below desired success thresholds. Furthermore, the authors performed only a limited outcomes analysis.

Some EMS services have improved procedural experience and proficiency by using fewer targeted-response paramedics.5, 92, 93 In the original implementation effort by DeLeo, the investigator purposely constrained the number of paramedic units to maximize out-of-hospital endotracheal intubation procedural exposure.3 Although feasible in dense urban settings, these strategies may not be possible in remote rural areas where ambulances already cover large geographic distances. These approaches are also at odds with the efforts of communities seeking to increase the number of paramedics in their regions.94

In the spirit of seeking system-level improvements, one cannot ignore the question, Should we intubate at all? For apneic or near-apneic patients, alternate airways such as the Combitube (esophageal-tracheal twin-lumen airway device; Kendall, Inc., Mansfield, MA) and laryngeal mask airway (LMA North America, San Diego, CA) have appealing characteristics and are supported by some data.95, 96, 97, 98 These devices are conceptually simpler than endotracheal intubation, easier to insert than endotracheal tubes, require less training, and are less subject to skill decay.71, 96, 99, 100, 101 These devices have been extensively used as primary and secondary airway management devices.102, 103, 104 There is wide experience with the use of these devices by nonphysicians and even basic-level rescuers.97, 101, 105, 106, 107, 108, 109, 110, 111, 112 Combitubes and laryngeal mask airways offer ventilation and oxygenation comparable with endotracheal intubation in controlled and field settings.96, 100, 113, 114, 115 Current advanced cardiac life support guidelines recommend the use of these devices when rescuers have only limited endotracheal intubation experience.116

Combitubes and laryngeal mask airways have important adverse effects, limitations, and concerns, including many similar to those of endotracheal intubation.45, 117, 118, 119, 120, 121, 122 Most important, their links to patient outcome have not been defined. Before Combitubes and laryngeal mask airways can formally replace endotracheal intubation, we must perform careful systematic evaluations to verify their safety and effectiveness.

Conclusion

The current literature highlights shortcomings associated with out-of-hospital endotracheal intubation. Few studies affirm current practice. Few studies have demonstrated improved outcome from out-of-hospital endotracheal intubation in any disease group, and several studies describe worsened outcomes. In many studies, adverse events and errors associated with out-of-hospital endotracheal intubation are frequent. Out-of-hospital endotracheal intubation may inadvertently interact with other physiologic processes key to optimizing resuscitation. Significant system-level barriers limit opportunities for endotracheal intubation training and clinical experience. Scientists, medical directors, and clinicians must strive to better understand and ultimately improve this key intervention.

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Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA.

Address for correspondence: Henry E. Wang, MD, MPH, University of Pittsburgh School of Medicine, Department of Emergency Medicine, 230 McKee Place, Suite 400, Pittsburgh, PA, 15213; 412-647-4925, fax 412-647-6999

Supervising editor: Robert K. Knopp, MD

Funding and support: Dr. Wang is supported by Clinical Scientist Development Award K08-HS013628 from the Agency for Healthcare Research and Quality, Rockville, MD.

Reprints not available from the authors.

PII: S0196-0644(06)00075-8

doi:10.1016/j.annemergmed.2006.01.016

© 2006 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

[mediccjh]

So in other words, no one has a f--king clue as to whether pre-hospital intubation is good.

[AZCEP]

At least there are more and more articles being written about it. Unlike some things, that get one, intubation has had dozens that have actually looked at both sides of the issue.

Hopefully we are learning from these.