Doxapram improves pulmonary function after upper abdominal surgery.
The effects of doxapram on postoperative pulmonary function were studied in 40 ASA I and II patients randomly allocated to receive either doxapram 1.8 mg.kg-1.h-1 or placebo for 2 h immediately after elective cholecystectomy. The two groups displayed similar reductions of carbon dioxide production at 2 h and 6 h postoperatively, whereas oxygen consumption remained at preoperative levels for 24 h. Minute ventilation was similarly reduced in the two groups at 2 h and 6 h postoperatively, with corresponding increases in PaCO2. PaO2 was similarly and significantly decreased in both groups postoperatively, whereas P(A-a)O2 remained unchanged at 2 h and 6 h in doxapram-treated patients. FRC was reduced postoperatively in both groups, significantly more so in the control group at 6 h. Various indices of intrapulmonary gas distribution, including the functional (nitrogen) dead space, underwent similar changes in the two groups. By contrast, the physiological dead space was reduced in doxapram-treated patients at 2 h, 6 h and 24 h postoperatively, whereas no significant changes were seen in the control group. The ventilatory equivalent for CO2 was significantly lower in the doxapram-treated group, implying higher ventilatory efficiency. Our findings indicate that infusion of doxapram postoperatively attenuates the impairment of pulmonary function postoperatively, chiefly via effects on V'A/Q' ratios. No side effects of doxapram were observed.
Björk
L
L
Department of Anesthesiology, Malmö General Hospital, Sweden.
Arborelius
M
M
Renck
H
H
Rosberg
B
B
D000005:Abdomen / Q000601:surgery*; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000378:metabolism; D002763:Cholecystectomy; D004315:Doxapram / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005652:Functional Residual Capacity / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D008168:Lung / Q000187:drug effects* / Q000502:physiology*; D008170:Lung Compliance / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009325:Nausea / Q000139:chemically induced; D010101:Oxygen Consumption / Q000187:drug effects; D010919:Placebos; D011650:Pulmonary Alveoli / Q000187:drug effects; D012119:Respiration / Q000187:drug effects; D012126:Respiratory Dead Space / Q000187:drug effects; D013990:Tidal Volume / Q000187:drug effects; D014839:Vomiting / Q000139:chemically induced
D010919:Placebos; D002245:Carbon Dioxide; D004315:Doxapram