CHEST Guidelines-Safety-Considerations-Regarding-Noninvasive-Positi

Safety-Considerations-Regarding-Noninvasive-Positi

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In March 2015, a correspondence in the journal <em>CHEST</em> discussed safety concerns regarding the use of Noninvasive Positive Pressure Ventilation (NPPV) after esophagectomy, highlighted by Dr. Michele Carron. The discussion builds on an article by Raman et al., which demonstrated in a pig model that esophagectomy anastomoses can tolerate higher pressures than those encountered during NPPV, suggesting that NPPV could be safe post-esophagectomy. Despite these findings, Dr. Carron advises caution when using pressures over 20 cm H2O during NPPV in clinical settings.

Carron points out significant variability in pressure tolerance in models, noting that the lowest pressure tolerated before leakage in ex vivo anastomoses was 21 cm H2O. There's also an increased risk of gastric insufflation at pressures above 20 cm H2O, which can lead to complications like decreased venous outflow, vascular congestion, and increased wall tension that might augment ischemic effects during gastric transposition.

Furthermore, as NPPV directs ventilation volume between lungs and stomach based on respiratory resistance and esophageal sphincter pressure, it can destabilize the upper esophageal sphincter. This is especially critical since protective lower esophageal sphincter functions are often lost post-esophagectomy. This dysfunction can allow air escape from the stomach to esophagus, triggering esophageal sphincter relaxation, and potentially leading to aspiration and pneumonia. 

Preventive strategies like nasogastric tube placement for aspiration and aggressive acid reduction are recommended to counteract such risks.

The correspondence emphasizes that while NPPV can be aligned post-esophagectomy, it must be cautiously managed to prevent pressing health risks, considering pressures used in the procedure and the physiological changes following esophageal surgery.

Keywords

Noninvasive Positive Pressure Ventilation

NPPV

esophagectomy

safety concerns

pressure tolerance

gastric insufflation

esophageal sphincter

aspiration risk

postoperative care

nasogastric tube