Negative Pressure Ventilators

[LifeguardsForLife]

Do any of you have any experience with negative pressure ventilators? Are they still in use, and what would indicate their use over positive pressure ventilators?

[Kaisu]

... paging Ventmedic - Ventmedic to the forums please.....

[LifeguardsForLife]

... paging Ventmedic - Ventmedic to the forums please.....

haha Kaisu, I had also posted this over at another forum, though figured I had a better chance of getting valuable information over here.

[chbare]

Negative pressure ventilation is still around. The following is an article from 1996 that is dated as far as current literature; however, many of the conditions and potential conditions that can benefit from NPV modalities are covered.

http://www.erj.ersjournals.com/cgi/reprint/9/7/1531

The following is a newer review of prospective literature. It is actually somewhat limited for NPV when considering using NPV for acute conditions; however, it does appear that NPV could have a role. Clearly, I think a modality that helps the patient and prevents intubation has potential. However, I am not sure how NPV would compare to less invasive positive pressure techniques such as CPAP and BiPAP. I have even seen literature stating good results when patients were liberated from the ventilator by extubating and transitioning to less invasive ventilation techniques. As I remember, many of these patients did not undergo traditional spontaneous awake breathing trials. Therefore, I suspect it takes a massive pair to simply extubate and trust the less invasive modality to do the rest. I will try to pull the literature. Dr. Jeffrey Guy actually presented these studies in a recent podcast from his ICU rounds series. Free iTunes download. I will try to find the exact podcast.

http://www.erj.ersjournals.com/cgi/content/full/20/1/187

Take care,

chbare.

[LifeguardsForLife]

Thank you all for your much valued responses. For any other members interested, I think the following article also answered some of the other questions I had regarding negative pressure ventilations.

http://chestjournal..../2217.full.html

IMV is very effective treatment for respiratory failure but can be associated with many complications, especially in patients requiring prolonged intubation. Complications included laryngeal and tracheal trauma with potential long-term effects, such as stenosis. In addition, sinusitis and VAP can occur during IMV. The incidence of complications is closely related to the duration of invasive ventilation, particularly the acquisition of VAP.²¹

Difficult weaning is often a problem in patients with COPD who undergo invasive ventilation. To avoid these problems and reduce hospital stay, many ICUs perform tracheostomy precociously, leading to high human and social costs due to this artificial airway. In the last 10 years, many studies have reported positive results regarding NIMV treatment for exacerbation of CRF primarily in patients with COPD.

The iron lung is our first choice of treatment for several reasons. Patients with acute exacerbation of CRF often present inspiratory muscle weakness, rapid shallow breathing, and excessive CO₂ retention. The iron lung improves the performance of respiratory muscles and restores sufficient respiratory compensation.¹⁶ Furthermore, many patients in the early phase of ARF are restless and do not tolerate NPPV with nasal or full face mask, whereas with the iron lung these patients receive ventilation effectively. Tracheobronchial secretions are often a problem in patients treated with NIMV and require efficient cleaning of the airways (with catheter or fiberoptic bronchoscope). This is achieved more easily when the iron lung is used.²² Noncontrolled studies²³²⁴²⁵ indicate a better survival rate when patients with COPD and ARF are treated with the iron lung vs IMV. Using controlled ventilation via iron lung, patients with COPD in hypercapnic-induced coma can be safely treated.²⁶

Edited December 27, 2009 by LifeguardsForLife