Journal of cardiothoracic anesthesia
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J Cardiothorac Anesth · Feb 1989
Randomized Controlled Trial Comparative Study Clinical TrialComparison among manual, computer-assisted, and closed-loop control of blood pressure after cardiac surgery.
Forty-five patients who required vasodilator therapy for systemic arterial hypertension following cardiac surgery were randomly allocated to receive: (1) manual control of a sodium nitroprusside (SNP) infusion; (2) computer-assisted control where the nurse was provided with a color graphical display of performance; or (3) automatic closed-loop control. Limits of acceptable systolic pressure were prescribed for each patient, and the percentage time spent outside these limits was calculated for each patient. ⋯ The results suggest that the quality of blood pressure control achieved by nurses can be improved by providing them with a clear graphical display of their performance. Better control of blood pressure should reduce the adverse effects of hypotension and hypertension following cardiac surgery.
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J Cardiothorac Anesth · Feb 1989
Comparative StudyA comparison of radial, brachial, and aortic pressures after cardiopulmonary bypass.
Previous investigations have identified falsely low radial artery pressures after cardiopulmonary bypass (CPB). The present study investigates the relationship among radial, brachial, and aortic arterial pressures in 33 cardiac surgical patients following CPB. Two minutes after separation from CPB, clinically important (greater than or equal to 10 mmHg) underestimation of systolic aortic pressures occurred in 17 of 33 (52%) radial artery catheters, while occurring in seven of 33 (21%) brachial artery catheters. ⋯ Brachial artery systolic and mean pressures were higher than corresponding radial artery measurements two minutes after CPB (P less than 0.05), followed by gradual resumption of a normal brachial-to-radial pressure relationship over 60 minutes. Either vasospasm in the brachial and radial arteries or profound arteriolar vasodilation in the upper extremity might cause the observed central-to-peripheral arterial pressure differences. The progressive central-to-peripheral decrease in mean arterial pressure favors the latter mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Cardiothorac Anesth · Feb 1989
Cardiovascular effects of a nifedipine infusion during fentanyl-nitrous oxide anesthesia in dogs.
The hemodynamic effects of a nifedipine infusion were investigated in eight dogs given fentanyl/pancuronium/nitrous oxide/oxygen anesthesia. Nifedipine (20 micrograms/kg) was given intravenously over two minutes immediately prior to each 30-minute infusion at 2 micrograms/kg/min, 4 micrograms/kg/min, and 6 micrograms/kg/min. The range of plasma nifedipine levels obtained was 52.1 to 113.7 ng/mL. ⋯ Administration of calcium chloride (20 mg/kg) after the nifedipine infusion had no effect on SVR or MAP, but HR was significantly reduced. Serum epinephrine and norepinephrine levels increased after the infusion of nifedipine and suggested that fentanyl did not completely overcome the sympathetic response to the profound vasodilatation. The resulting tachycardia in combination with diastolic hypotension from nifedipine could have a detrimental effect on the myocardial oxygen balance.