Chlorazepate for premedication.
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Anti-Anxiety Agents↗
Biomedical subjects
D E Jeal
Publications and source records attributed to D E Jeal.
A method of controlled ventilation with a circle-absorber breathing system.
A simple method of adapting a pressure-cycled ventilator of the flow generator type to ventilate patients on a circle-absorber anaesthetic system is described. Standard lengths of corrugated black rubber tubing are placed between the ventilator and the circle-absorber is deadspace, replacing the reservoir bag. The performance of this modification was investigated and a functional volume for the tubing calculated. There was a simple relationship between the tidal volume, the length of tubing and the fresh gas flow required to avoid dilution of the anaesthetic gases by the driving gases.
Anesthesia, Inhalation↗
I.V. doxapram hydrochloride and pulmonary complications after lower abdominal surgery.
An i.v. solution of 0.9% saline or 0.9% saline with doxapram 2 mg/ml was administered to 260 obstetric and gynaecological patients who breathed 35% oxygen following lower abdominal surgery. Arterial blood was sampled before and during the infusion in 104 subjects. With the administration of doxapram mean PaCO2 decreased, and arterial oxygenation improved. In both treatment groups respiratory complications occurred with the same low frequency (less than 15%). The majority of patients received antibiotics following surgery, but in 34 who did not, the incidence of pulmonary complications was significantly less following doxapram.
Abdomen↗
Ketamine for anaesthetic induction at Caesarean section.
Fifty healthy mothers, with normal placental function, were anaesthetised with ketamine (2 mg/kg body mass) for Caesarean section. Surgery was conducted with the patient in the lateral tilt position and anaesthesia was maintained with nitrous oxide, oxygen, muscle relaxants and controlled ventilation. Eight of the 50 infants delivered were clinically depressed, judged on the basis of the modified Apgar score at 2 minutes after delivery. The average time to sustained respiration was 58, 1 minutes. Studies of maternal blood gases before induction and at delivery revealed mild respiratory alkalosis, associated with an appropriate degree of compensatory metabolic acidosis. Umbilical cord blood gas analysis showed the presence of a fetal respiratory acidosis. The average derived fetal base excess levels were similar to those obtained in a previous study with thiopentone anaesthesia, but calculated mean maternal-to-fetal pH and base excess gradients were slightly greater in the present study. Prolonged induction-to-delivery intervals were associated with an increase in maternal metabolic and fetal respiratory acidosis. Slow delivery of the infant after invasion of the uterus magnified the degree of fetal metabolic acidosis, and widened the maternal-to-fetal acid-base gradients. Convincing evidence of maternal awareness during surgery was not obtained in this study. Five patients had hallucinations in the immediate postanaesthetic period. Unpleasant dreams were reported by 10% of patients. Delirium on emergence from anesthesia was not encountered. In this study, ketamine appeared to maintain fetoplacental exchange adequately, but may have been responsible for some degree of drug-induced neonatal depression. It is suggested that ketamine should be re-evaluated, using a lower dosage schedule, for Caesarean section.
Acid-Base Equilibrium↗
Anaesthetic induction for Caesarean section with propanidid.
Propanidid was used for the induction of anaesthesia at Caesarean section in 50 healthy mothers. All parturients were considered to have normal placental function. Anaesthesia was maintained with nitrous oxide, oxygen, muscle relaxant and controlled ventilation. The patients were tilted laterally with a 15 degrees rubber wedge during the procedure in order to obviate the effects of aorta-caval occlusion. At the time of delivery, arterial blood was drawn from the mother and from the vessels of a double clamped section of umbilical cord, for blood-gas analysis. The results obtained are compared with those previously reported in a similar series anaesthetised with thiopentone, gas, oxygen and relaxant. Maternal blood-gas and acid-base levels were similar in the two groups at delivery. The clinical status of the infants in the present series, as judged by the modified Apgar score at 2 minutes after birth, was satisfactory. Umbilical venous and arterial pH values after propanidid were both 0-054 units (P less than 0-001) less than those following thiopentone; and average base deficits were 3-1 (Uv) and 3-9 (Ua) mEq/litre greater after propanidid (P less than 0-001). Mean oxygen levels in the umbilical cord bloods were 8-0 (Uv) and 3-5 (Ua) mmHg lower (P less than 0-001 & P less than 0-025 respectively) in the propanidid group. Derived oxygen contents was also significantly less than in the previous thiopentone series. (Ma-Uv) and (Ma-Ua) gradients were 0-053 and 0-051 pH units higher after propanidid than that following thiopentone (P less than 0-001). Mean (Ma-Uv) and (Ma-Ua) base deficits were 3-5 and 3-9 mEq/litre greater (P less than 0-001). Five patients offered definite evidence of factual recall, of whom three experienced pain. Propanidid, therefore, appeared to be associated with a greater degree of foetal acidaemia than did thiopentone. In addition, painful factual recall during surgery was encountered in 6 percent of cases. It is concluded that propanidid, although theoretically offering advantages over thiopentone to the obstetric anaesthetist, in practice, did not fulfil this promise.
Anesthesia, Intravenous↗
Anaesthesia for Caesarean section with ketamine.
Fifty healthy mothers, with normal placental function, were anaesthetised with ketamine for Caesarean section. Anaesthesia was maintained with nitrous oxide, oxygen, muscle relaxants and controlled ventilation. Surgery was conducted in the lateral tilt position. Arterial blood samples were drawn from the mothers, and from the vessels of a double clamped section of umbilical cord, for blood-gas analysis. Results obtained were compared with those of a previous series anaesthetised with thiopentone, nitrous oxide, oxygen and muscle relaxants. Eight infants were clinically depressed, judged on the basis of their modified Apgar score 2 minutes after delivery. The average time to sustained respiration (TSR) was 58.1 seconds. The mean maternal pH and base excess values in the ketamine group were significantly greather than those reported after thiopentone anaesthesia. Mean Uv and Ua pH levels were also significantly higher after ketamine; in contrast, the average fetal base excess values did not differ from those obtained previously with thiopentone. The mean (Ma-Uv) and (Ma-Ua), pH gradients were 0.019 and 0.025 pH units greater respectively in the ketamine group compared to the thiopentone (P less than 0.005). The average (Uv-Ua) PO2 gradient was 3.4 mmHg less after ketamine anaesthesia (P less than 0.005). A significant inverse correlation was observed relating the I-D interval to the Ma and Ua pH values. Maternal arterial base deficit values appeared to increase with delay in delivering the fetus. Prolongation of the uterine incision to delivery (U-D) interval was associated with a decrease in Ua pH and base excess values. (Ma-Ua) pH and base excess gradients increased with lengthening of the U-D interval. No convincing evidence of awareness during anaesthesia was found during the study. Five patients, appeared to be hallucinated in the immediate post-anaesthetic period. Unpleasant dreams were reported in 5 instances. In this study ketamine appeared to be unassociated with significant biochemical asphyxia, but may have been responsible for some element of drug induced neonatal depression. In view of our own experience and that of other workers, it is suggested that ketamine induction for Caesarean section should be re-evaluated using a lower dose of the drug.
Anesthesia, General↗
Propanidid for anaesthetic induction at Caesarean section.
In 50 healthy mothers scheduled for elective Caesarean section, anaesthesia was induced with propanidid (7 mg/kg body weight). Thereafter, ventilation was controlled with nitrous oxide, oxygen and muscle relaxants. A further dose of propanidid (1 mg/kg body weight) was administered 3 minutes after the initial injection of this drug, as a means of preventing maternal awareness during equilibration with the anaesthetic gas mixture. The acid-base status of the mothers before the induction of anaesthesia, and at delivery, revealed a mild degree of respiratory alkalosis with a compensatory metabolic acidosis. Umbilical cord blood gas results indicated the presence of significant fetal acidosis, both respiratory (mean pCO2 Uv 46,3 torr (SD 11,3) and Ua 54,3 torr (SD 12,0)), and metabolic (mean base excess Uv-9 mEq/l (SD 4,2) and Ua-11,8 mEq/l, (SD 5,0)) in origin. The average umbilical cord blood oxygen tensions were Uv 25,9 torr (SD 10), and Ua 15,4 torr (SD 8,5); mean maternal to fetal base-excess gradients were Ma-Uv 4,1 mEq/l (SD 2,8) and Ma-Ua 6,5 mEq/l (SD 3,5). Five mothers (10%) offered convincing evidence of factual recall during surgery, and 3 of these were aware of pain. Nausea and vomiting occurred in 5 patients and in 4 there were clinical signs of postoperative chest infection. The degree of fetal biochemical asphyxia, and the incidence of maternal awareness during surgery, were significantly greater than previously reported when thiopentone was used for the induction of anaesthesia for Caesarean section. The results obtained are discussed, and the conclusion is drawn that propanidid for anaesthesia appears to offer no advantage over thiopentone in obstetric practice.
Acidosis↗
The Cape "Minor" and the circle absorber system.
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Ventilators, Mechanical↗