Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1996
Comparative Study Clinical TrialAprotinin prolongs activated and nonactivated whole blood clotting time and potentiates the effect of heparin in vitro.
This study was designed to evaluate the effect of aprotinin on activated versus nonactivated whole blood clotting time using two different on-site methods and to quantify these anticoagulant properties when compared to heparin in a controlled, in vitro environment. Blood specimens were obtained prior to heparin administration from 56 patients undergoing cardiac surgery. Specimens obtained from the first consecutive 20 patients were mixed with either normal saline (NS) or aprotinin (400 kallikrein inhibiting units (KIU)/mL), inserted into Hemochron tubes containing either NS or heparin (0.3 or 0.6 U/mL) and then used to measure celite-activated (celite ACT) and nonactivated whole blood clotting time (WBCT1) using four Hemochron instruments. ⋯ On average, 200 KIU/mL of aprotinin prolonged WBCT2 to the same extent as 0.69 +/- 0.28 U/mL of heparin using linear regression models within each patient. Aprotinin significantly prolongs activated or nonactivated whole blood clotting time measurements in a dose-dependent manner. Since prolongation of whole blood clotting time by heparin is potentiated by aprotinin in vitro, aprotinin's anticoagulant properties may in part account for the prolonged celite activated clotting time values observed in the presence of aprotinin.
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Anesthesia and analgesia · Jun 1996
Comparative Study Clinical TrialThe relationship between cerebral blood flow and transcranial Doppler blood flow velocity during hypothermic cardiopulmonary bypass in adults.
A noninvasive, simple, and continuous method to assess cerebral perfusion during cardiopulmonary bypass (CPB) could help prevent cerebral ischemia. Transcranial Doppler sonography (TCD) allows a noninvasive, on-line measurement of blood flow velocity in cerebral arteries. The correlation of TCD-estimated and actual cerebral blood flow (CBF) has not been well studied during CPB. ⋯ The pooled change in MCA velocity and CBF as percentage of baseline (prebypass) for all patients and at all time points had a correlation of 0.33 (r). A decrease or increase in MCA velocity did not necessarily indicate a corresponding decrease or increase in CBF. This technology may be of limited usefulness during the circulatory condition of hypothermic, nonpulsatile CPB.
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Anesthesia and analgesia · Jun 1996
Comparative StudyPreoperative airway assessment: predictive value of a multivariate risk index.
Using readily available and objective airway risk criteria, a multivariate model for stratifying risk of difficult endotracheal intubation was developed and its accuracy compared to currently applied clinical methods. We studied 10,507 consecutive patients who were prospectively assessed prior to general anesthesia with respect to mouth opening, thyromental distance, oropharyngeal (Mallampati) classification, neck movement, ability to prognath, body weight, and history of difficult tracheal intubation. After induction of anesthesia, the laryngeal view during rigid laryngoscopy was graded and the ability of experienced anesthesia personnel to ventilate via a mask was determined. ⋯ A composite airway risk index (derived from nominalized odds ratios calculated from the multivariate model) as well a simplified (0 = low, 1 = medium, 2 = high) risk weighting exhibited higher positive predictive value for laryngoscopy Grade IV at scores with similar sensitivity to Mallampati class III, as well as higher sensitivity at scores with similar positive predictive value. Compared to Mallampati class I fewer false-negative predictions were observed at a risk index value of 0. We conclude that improved risk stratification for difficulty with visualization during rigid laryngoscopy (Grade IV) can be obtained by use of a simplified preoperative multivariate airway risk index, with better accuracy compared to oropharyngeal (Mallampati) classification at both low- and high-risk levels.
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Anesthesia and analgesia · Jun 1996
Comparative Study Clinical TrialTransesophageal echocardiography in myocardial revascularization: II. Influence on intraoperative decision making.
This study was conducted to determine how transesophageal echocardiography (TEE) guides intraoperative decision making during myocardial revascularization. Although its usefulness in influencing clinical decision making during cardiac valvular surgery is well documented, the clinical utility of TEE in patients undergoing myocardial revascularization is less clear. We studied the performance of five community-based, full-time cardiac anesthesiologists during 75 surgical procedures. ⋯ TEE is often influential in guiding decision making in myocardial revascularization when incorporated as a routine monitor in the intraoperative setting. Information from TEE has been most commonly used to guide the management of fluid administration and institution of antiischemic therapy. In a small subset of patients, TEE appears to be useful in guiding critical surgical interventions.