Key result
Morphine and halothane supplements to N2O-O2 anesthesia caused significant increases in heart rate, rate pressure product, and pulmonary capillary wedge pressure after endotracheal intubation.
Why the study?
Do different anesthetic supplements to N2O-O2 anesthesia prevent cardiovascular response during endotracheal intubation in patients?
Do different anesthetic supplements to N2O-O2 anesthesia prevent cardiovascular response during endotracheal intubation in patients?
N2O-O2 anesthesia supplemented with morphine or halothane at 1 MAC does not adequately prevent cardiovascular responses to endotracheal intubation, requiring additional anesthetic depth or adjuvants.
May not blunt intubation responses; leaves open optimal depth or adjuvants in prospective trials.
In order to investigate the impact of four different anesthetic regimens on the cardiovascular response to endotracheal intubation, 24 patients were anesthetized to approximately the same depth of anesthesia (MAC-fraction) using one of four supplements to N2O-O2 (60:40) anesthesia: Group 1 = morphine 0.5 mg/kg i.v., Group 2 = Innovar 0.1 ml/kg i.v., Group 3 = halothane, 0.4% end-tidal, Group 4 = enflurane 0.7% end-tidal. Cardiovascular variables were recorded from radial arterial and thermistor-tipped pulmonary artery catheters and were determined at the following times: (1) while the patients were awake prior to induction of anesthesia; (2) after a stable level of anesthesia had been induced; and (3) within the first minute after endotracheal intubation. Only the groups receiving morphine and halothane sustained significant increases in heart rate, rate pressure product and pulmonary capillary wedge pressure after intubation. It is concluded that N2O-O2 anesthesia supplemented with either morphine or halothane at the 1 MAC dose level does not adequately prevent cardiovascular response after endotracheal intubation, and that these techniques require additional anesthetic depth or other adjuvant drugs in order to prevent cardiovascular complications.
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Bedford et al. (1984) studied Patients undergoing endotracheal intubation (n=24). Morphine, Innovar, halothane, or enflurane supplements to N2O-O2 anesthesia vs. Active comparators (four groups) was evaluated on Cardiovascular response (heart rate, rate pressure product, and pulmonary capillary wedge pressure). Morphine and halothane supplements to N2O-O2 anesthesia caused significant increases in heart rate, rate pressure product, and pulmonary capillary wedge pressure after endotracheal intubation.
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