Gs. Murphy et al., Influence of a vital capacity maneuver on pulmonary gas exchange after cardiopulmonary bypass, J CARDIOTHO, 15(3), 2001, pp. 336-340
Objective: To investigate the effect of a single, vital capacity breath (vi
tal capacity maneuver [VCM]), administered at the end of cardiopulmonary by
pass (CPB), on pulmonary gas exchange in patients undergoing coronary arter
y bypass graft surgery.
Design: Prospective, randomized, double-blind study.
Setting: University-affiliate hospital.
Participants: Forty patients scheduled for elective coronary artery bypass
graft surgery and early tracheal extubation.
Interventions: Patients were randomized to 1 of 2 groups. VCM: patients rec
eived a VCM at the conclusion of CPB. Control patients received no VCM. Mea
surements and
Main Results: Intrapulmonary shunt (Q(S)/Q(T)) arterial oxygenation (PaO2),
and alveolar-arterial oxygen gradients (P(A-a)O-2) were measured after ind
uction of anesthesia, CPB, intensive care unit (ICU) arrival, and extubatio
n. The duration of postoperative intubation was recorded for each group. O-
S/Q(T) increased significantly 30 minutes after CPB in the control group (1
5.7 +/- 1.8% to 27.4 +/- 2.6%; p = 0.01). In the VCM group, a small decreas
e 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)O-2 in the control group at
induction of anesthesia, no differences in PaO2 or P(A-a)O-2 were present
between the 2 groups at any measurement interval. Patients who received a V
CM were extubated earlier than the control group (6.5 +/- 2.1 hours v 9.4 /- 4.2 hours; p = 0.01).
Conclusion: The use of a VCM prevented an increase in O-S/Q(T) from occurri
ng in the operating room. Although a VCM did not influence pulmonary gas ex
change in the ICU, its application in the operating room appears to exert a
beneficial effect on tracheal extubation times after cardiac surgery. Copy
right (C) 2001 by W.B. Saunders Company.