Influence of a vital capacity maneuver on pulmonary gas exchange after cardiopulmonary bypass.
OBJECTIVE
To investigate the effect of a single, vital capacity breath (vital capacity maneuver [VCM]), administered at the end of cardiopulmonary bypass (CPB), on pulmonary gas exchange in patients undergoing coronary artery bypass graft surgery.


METHODS
Prospective, randomized, double-blind study.


METHODS
University-affiliated hospital.


METHODS
Forty patients scheduled for elective coronary artery bypass graft surgery and early tracheal extubation.


METHODS
Patients were randomized to 1 of 2 groups. VCM patients received a VCM at the conclusion of CPB. Control patients received no VCM.


RESULTS
Intrapulmonary shunt (Q(S)/Q(T)), arterial oxygenation (PaO2), and alveolar-arterial oxygen gradients (P(A-a)O2) were measured after induction of anesthesia, CPB, intensive care unit (ICU) arrival, and extubation. The duration of postoperative intubation was recorded for each group. Q(S)/Q(T) increased significantly 30 minutes after CPB in the control group (15.7 +/- 1.8% to 27.4 +/- 2.6%; p = 0.01). In the VCM group, a small decrease in Q(S)/Q(T) occurred (16.1 +/- 2.0% to 14.9 +/- 2.0%). After ICU arrival and extubation, no significant difference in Q(S)/Q(T) existed between the 2 groups. With the exception of a higher P(A-a)O2 in the control group at induction of anesthesia, no differences in PaO2 or P(A-a)O2 were present between the 2 groups at any measurement interval. Patients who received a VCM were extubated earlier than the control group (6.5 +/- 2.1 hours v 9.4 +/- 4.2 hours; p = 0.01).


CONCLUSIONS
The use of a VCM prevented an increase in Q(S)/Q(T) from occurring in the operating room. Although a VCM did not influence pulmonary gas exchange in the ICU, its application in the operating room appears to exert a beneficial effect on tracheal extubation times after cardiac surgery.
Murphy
G S
GS
Departments of Anesthesia and Surgery, Evanston Northwestern Healthcare/Northwestern University, Evanston, IL, USA.
Szokol
J W
JW
Curran
R D
RD
Votapka
T V
TV
Vender
J S
JS
D000368:Aged; D002315:Cardiopulmonary Bypass; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D014797:Vital Capacity / Q000502:physiology*