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.