Anesthesiology
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End-tidal CO2 (PETCO2), arterial CO2 (PaCO2), mixed expired CO2 (PECO2), arterial and mixed venous oxygen contents were measured and the PaCO2 to PETCO2 difference (delta PCO2), physiologic dead space to tidal volume ratios (VD/VT) and venous admixture (Qs/Qt) were calculated in 41 anesthetized infants and children undergoing repair of congenital cardiac lesions. Eighteen children were acyanotic; 9 with normal pulmonary blood flow (PBF) and normal intracardiac anatomy (normal group); and 9 with increased PBF (acyanotic group). Twenty-three children were cyanotic; 14 with right to left intracardiac shunts and decreased PBF (cyanotic (D) group); and 9 with mixing lesions with normal or increased PBF (cyanotic (I) group). ⋯ Mean +/- SD VD/VT for the normal and acyanotic groups were 0.35 +/- 0.17 and 0.39 +/- 0.19, respectively (NS). Corresponding values for the cyanotic (D) group and cyanotic (I) group were 0.38 +/- 0.16 and 0.55 +/- 0.16, respectively (NS), and were significantly greater than those from the normal and acyanotic groups (P less than 0.05). The relationship of delta PCO2 to VD/VT and Qs/Qt demonstrated that VD/VT was the most important determinant of delta PCO2, but in instances where Qs/Qt were large (e.g., cyanotic congenital heart disease) the percentage contribution of Qs/Qt to the delta PCO2 can be considerable.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Incidence of emesis and postanesthetic recovery after strabismus surgery in children: a comparison of droperidol and lidocaine.
The authors sought to compare the antiemetic and sedative postanesthetic effects of droperidol versus lidocaine given intravenously. One hundred and fifty children, ASA physical status I or II, ages 2-15 yr, were studied. Each child was randomly assigned to receive either droperidol, 0.075 mg/kg; lidocaine, 1.5 mg/kg; or a combination of lidocaine, 1.5 mg/kg, and a reduced dose of droperidol, 0.025 mg/kg, immediately after induction of anesthesia, which was with thiopental, atropine, and succinylcholine. ⋯ However, the mean time intervals from completion of surgery to recovery of full alertness and to discharge from the hospital did not differ significantly among the three groups. In summary, the authors found that intravenous droperidol is significantly more effective than lidocaine in reducing the incidence of vomiting in unpremedicated children after strabismus surgery. Furthermore, droperidol did not delay either the time to recovery of full alertness or the time to discharge from hospital compared to lidocaine.
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When positive end-expiratory pressure (PEEP) is applied to normal lungs, the pulmonary artery occlusion pressure (PAOP) may reflect alveolar pressure and not left ventricular end-diastolic pressure (LVEDP). The reliability of PAOP measurements has been questioned when PEEP levels greater than 10 cm H2O are applied. To verify whether this disparity occurs in patients with severe lung injury, the authors simultaneously measured both PAOP and LVEDP at 0, 10, and 16-20 cm H2O PEEP in 12 supine patients with severe adult respiratory distress syndrome (ARDS). ⋯ In only six of 35 simultaneous measurements was the PAOP-LVEDP gradient 2 mmHg or more (2-3 mmHg in four, and 4 mmHg in two). In five patients, the highest PEEP level was 4-9 cm H2O greater than LVEDP; however, no gradient was measured between LVEDP and PAOP. The authors conclude that, in severe ARDS, a close correspondence between PAOP and LVEDP is maintained despite applying PEEP levels up to 20 cm H2O, suggesting that, in ARDS, surrounding pathology prevents transmitted alveolar pressure from collapsing adjacent pulmonary vessels.
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Randomized Controlled Trial Comparative Study Clinical Trial
The incidence of myocardial ischemia during anesthesia for coronary artery bypass surgery in patients receiving pancuronium or vecuronium.
This study was performed to compare the incidence of prebypass myocardial ischemia in patients receiving fentanyl and enflurane for anesthesia along with either pancuronium or vecuronium. Ninety-eight patients with normal left ventricular function were randomly allocated to receive either pancuronium 0.15 mg.kg-1 or vecuronium 0.15 mg.kg-1 in a double-blind manner after fentanyl 40 micrograms.kg-1 for induction of anesthesia for elective coronary artery bypass grafting (CABG). Premedication included diazepam 0.15 mg.kg-1 po, morphine 0.10 mg.kg-1, and scopolamine 0.005 mg.kg-1 im. ⋯ Eight patients developed 13 episodes of ischemia after administration of the muscle relaxant: four who received pancuronium (n = 44; 9%) and four receiving vecuronium (n = 54; 7%). Four episodes occurred at induction or tracheal intubation, two in each group. There were four perioperative myocardial infarctions as determined by ECG and CPK-MB levels, two in each group.(ABSTRACT TRUNCATED AT 250 WORDS)