Anesthesia and analgesia
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Anesthesia and analgesia · May 1981
Comparative StudyClinical evaluation of high-frequency positive-pressure ventilation (HFPPV) in patients scheduled for open-chest surgery.
Comparisons were made in 10 patients scheduled for thoracotomy between a prototype of a low-compressive system (Bronchovent Special) for volume-controlled, high-frequency positive-pressure ventilation (HFPPV; fixed frequency of 60/min; fixed relative insufflation time of 22%), and a conventional respirator (SV-900) for intermittent positive-pressure, volume-controlled ventilation at a frequency of 20/min, after induction of anesthesia, but before surgery. With both ventilator systems intratracheal, intrapleural, systolic, diastolic, and mean arterial systemic and central venous pressures were measured at normoventilation (normocarbia). Mean intratracheal pressure and mean intrapleural pressure were significantly lower with volume-controlled HFPPV (1.3 +/- 0.5 and -4.0 +/- 2.1 (SD) cm H2O, respectively) than with conventional volume-controlled ventilation with SV-900 (2.1 +/- 1.2 and -3.0 +/- 1.5 cm H2O, respectively). ⋯ After compression the lung was readily re-expanded with the aid of a brief period of positive end-expiratory pressure (PEEP). Thus, even relatively low intrapulmonary pressures during volume-controlled HFPPV without PEEP are adequate to keep the open-chest lung expanded during intrathoracic surgery. This creates optimal conditions for the surgeons.
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Anesthesia and analgesia · May 1981
Fentanyl-air-oxygen anesthesia for ligation of patent ductus arteriosus in preterm infants.
In 10 premature infants (1123 +/- 263 g), fentanyl citrate (30 to 50 microgram/kg) was used in conjunction with pancuronium (0.1 mg/kg) as the sole anesthetic for transthoracic ligation of patent ductus arteriosus. Ventilation was controlled with air and oxygen in concentrations sufficient to maintain transcutaneous PO2 between 50 and 70 torr. Circulatory stability was easily maintained throughout the procedure. "Stiff chest" was avoided by the use of muscle relaxants, and the infants were awake within 1 hour after the procedure.
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Anesthesia and analgesia · Apr 1981
Correlation between anticurare activity of tetanic stimulation and neostigmine in anesthetized man.
Frequency and dose-dependent changes in neuromuscular transmission were examined in 70 patients undergoing elective surgical procedures requiring the use of muscle relaxants. Anesthesia was induced with sodium thiopental and maintained with N2O-O2 and fractional dose of meperidine or fentanyl. Neuromuscular block was produced and maintained at 80% level with incremental intravenous doses of d-tubocurarine. ⋯ At a frequency of 200 Hz tetanic fade was followed by complete but transient posttetanic decurarization. The original control twitch tension was not exceeded in posttetanic or postdrug responses. It is concluded that the transient after effects of tetanic stimulation are closely related to the anticurare effects of neostigmine.
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Anesthesia and analgesia · Apr 1981
Characteristics of succinylcholine-produced phase II neuromuscular block during enflurane, halothane, and fentanyl anesthesia.
The characteristics of phase II neuromuscular block following repeated intravenous injections of succinylcholine (SCh) were determined in 15 adult patients during enflurane, halothane, or fentanyl-nitrous oxide anesthesia. The onset of phase II block (train-of-four ratio (T4) equal to 0.5) occurred following a cumulative SCh dose of 4.4 +/- 0.3 (SEM) mg/kg of enflurane, 5.1 +/- 0.5 mg/kg of halothane, or 6.4 +/- 0.5 mg/kg of fentanyl. The cumulative SCh dose producing phase II block during fentanyl-nitrous oxide anesthesia was significantly greater than during enflurane (p less than 0.01) or halothane (p less than 0.05) anesthesia. ⋯ The transition phase was delayed during fentanyl-nitrous oxide anesthesia, occurring after a cumulative SCh dose of 4 to 7 mg/kg. Following this transition, tachyphylaxis (decreased time between SCh injections) was observed in each study group. The T4 ratio in all three study groups stabilized at 0.15 to 0.25 after 7 to 8 mg/kg.