Anesthesia and analgesia
-
Anesthesia and analgesia · Dec 1984
Randomized Controlled Trial Clinical TrialEffect of heated humidified gases on temperature drop after cardiopulmonary bypass.
In an attempt to prevent the decrease in nasopharyngeal temperature (NPT) ("afterdrop") after cardiac surgery, 30 patients undergoing hypothermic cardiopulmonary bypass (CPB) were randomly assigned to receive humidified heated inspired gases at 45 degrees C at the proximal end of the endotracheal tube (group I) or dry gases at room temperature (group II), from the time of termination of CPB. All patients received high flow rates on CPB during the rewarming period with the use of vasodilator drugs when necessary. Both groups were comparable with respect to total bypass time, rewarming time, and temperature at termination of CPB. ⋯ The results indicate that heating and humidifying inspired gases do not prevent afterdrop and do not falsely increase the nasopharyngeal temperature. The reasons for the ineffectiveness of heated humidified gases may include a large heat deficit at termination of CPB despite a normal NPT, and the very small heat content of heated gases. Monitoring the temperature of a site that reflects the heat deficit, and a more complete rewarming during CPB are suggested as a better approach to the prevention of afterdrop.
-
Anesthesia and analgesia · Dec 1984
The effects of nitrous oxide on myocardial metabolism and hemodynamics during fentanyl or enflurane anesthesia in patients with coronary disease.
Twenty patients about to have coronary artery bypass grafts were studied before and after 15 min of 50% nitrous oxide added to either fentanyl (75 micrograms/kg) or enflurane (0.5%) anesthesia. Arterial and central pressures and cardiac output were measured, plus coronary sinus blood flow and arterio-coronary sinus differences in oxygen, hemoglobin, and lactate contents. Fentanyl-N2O and enflurane-N2O both decreased systemic resistance, heart rate, cardiac output, and hence arterial pressure. ⋯ Hemodynamic depression occurred from the combined effects of nitrous oxide and fentanyl or enflurane. The beta-blocked myocardia of nonstimulated coronary patients were becoming ischemic globally on 50% oxygen, after significant hypotension. From this and other evidence, we conclude that nitrous oxide may not be benign in patients with coronary arterial disease.
-
Anesthesia and analgesia · Dec 1984
Comparative StudyComparison of fentanyl, sufentanil, and alfentanil anesthesia in patients undergoing valvular heart surgery.
The hemodynamic responses to anesthesia and surgery were studied in three groups of 20 patients undergoing valve replacement surgery. Anesthesia was induced with either fentanyl (75 micrograms/kg), sufentanil (15 micrograms/kg), or alfentanil (125 micrograms/kg). Pancuronium (8 mg) was given for muscle relaxation and the lungs were ventilated with oxygen/air (FIO2 = 0.5). ⋯ There were no other statistically significant changes within the groups. Four patients (two in the sufentanil group and one from each of the other groups) developed transient hypotension during induction of anesthesia. It is concluded that all three opioids can provide satisfactory anesthesia for patients having valve replacement surgery.
-
Anesthesia and analgesia · Dec 1984
Cerebral and cardiopulmonary responses to high-frequency jet ventilation and conventional mechanical ventilation in a model of brain and lung injury.
The cardiopulmonary and intracranial effects of high-frequency jet ventilation (HFJV) were evaluated in four groups of 10 mongrel dogs and compared to conventional mechanical ventilation with and without positive and expiratory pressure (PEEP). Each group of animals was studied with various combinations of normal and abnormal brain and lung function. Experimental brain injury (abnormal cerebral elastance) was produced by infusion of saline into the subarachnoid space to increase intracranial pressure (ICP), while lung injury resulted from intratracheal instillation of 0.1N HCl. ⋯ ICP responses did not vary significantly with the different modes of ventilation and were not influenced by the status of lung or brain function. However, significant reductions in cerebral perfusion pressure were noted with 20 cm H2O PEEP compared to HFJV. We conclude that unless high levels of PEEP (15-20 cm H2O) are required for adequate oxygenation, the cardiovascular and cerebral effects of HFJV do not differ significantly from those of conventional mechanical ventilation.