Study objectives: To investigate the short-term effects of noninvasive
ventilatory support (NIVS) on pulmonary gas exchange, ventilatory pat
tern, systemic hemodynamics, and pleural air leaks in patients submitt
ed to elective lung resection. Design: Prospective, randomized, parall
el, and controlled investigation. Setting: Thoracic Surgery Unit, Hosp
ital Universitari Son Dureta, Palma Mallorca, Spain. Patients: Ninetee
n patients electively submitted to lung resection because of varied cl
inical reasons. Interventions: Medical therapy was standardized for al
l patients, Ten subjects received NIVS with a nasal ventilatory suppor
t system (BiPAP) during 1 h (study group), The remaining nine individu
als constituted the control group. Measurements and results: Arterial
blood gases, ventilatory pattern, systemic hemodynamics, and pleural a
ir leaks were measured, Before surgery, there mere no significant clin
ical or functional differences between groups. After surgery, and comp
ared 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]O-2) (
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)O-2 re
mained unchanged in the control group throughout the study, PaCO2, the
ventilatory pattern, and systemic hemodynamics did not change signifi
cantly throughout the study in any group. Importantly, NIVS did not in
crease dead space to tidal volume ratio or worsen pleural air leaks. C
onclusions: Short-term NIVS with a ventilatory support system improves
the efficiency of the lung as a gas exchanger without noticeable nond
esired side effects in patients submitted to lung resectional surgery.