Study objectives: To investigate the short-term effects of noninvasive ventilatory support (NIVS) on pulmonary gas exchange, ventilatory pattern, systemic hemodynamics, and pleural air leaks in patients submitted to elective lung resection.
Design: Prospective, randomized, parallel, and controlled investigation.
Setting: Thoracic Surgery Unit, Hospital Universitari Son Dureta, Palma Mallorca, Spain.
Patients: Nineteen patients electively submitted to lung resection because of varied clinical reasons.
Interventions: Medical therapy was standardized for all patients. Ten subjects received NIVS with a nasal ventilatory support system (BiPAP) during 1 h (study group). The remaining nine individuals constituted the control group.
Measurements and results: Arterial blood gases, ventilatory pattern, systemic hemodynamics, and pleural air leaks were measured. Before surgery, there were no significant clinical or functional differences between groups. After surgery, and compared with preoperative measures, PaO2 decreased significantly (p<0.01) and to the same extent both in the study group (85.7±2.8 to 68.0±2.7 mm Hg) and the control group (83.6 ±2.5 to 67.3±2.6 mm Hg). In the study group, NIVS increased PaO2 (to 76.7±3.0 mm Hg; p<0.05) and decreased alveolar to arterial oxygen pressure gradient (P[A-a]O2) (27.2±2.7 to 17.6±2.3 mm Hg; p<0.05). This latter effect was still present 1 h after withdrawing NIVS. By contrast, PaO2 and P(A-a)O2 remained unchanged in the control group throughout the study. PaCO2, the ventilatory pattern, and systemic hemodynamics did not change significantly throughout the study in any group. Importantly, NIVS did not increase dead space to tidal volume ratio or worsen pleural air leaks.
Conclusions: Short-term NIVS with a ventilatory support system improves the efficiency of the lung as a gas exchanger without noticeable nondesired side effects in patients submitted to lung resectional surgery.