A nonoccluding bag and closed scavenging system for the Jackson Rees modified T-piece breathing system

We used the inner tube and its 22-mm connector from the patient end of a Bain breathing system to splint the double-ended bag of the Jackson Rees modification of the Ayre's T-piece breathing system. A paediatric airway pressure-limiting valve was connected to the distal end of the tube for closed scavenging. The resistance of the modified bags was similar to that of unmodified bags at gas flows below 11 l.min-1. The valve offered no resistance to gas flows below 5 l.min-1. During its use in 30 paediatric patients, analysis of carbon dioxide from inside the bag and from the expiratory port confirmed no loss of deadspace gas by preferential flow bypassing the bag into the scavenging system.     

Subarachnoid anaesthesia for elective Caesarean section

Forty patients who underwent elective lower segment Caesarean section under subarachnoid anaesthesia received either 2.0 ml 0.5% cinchocaine in 6% dextrose or 2.5 ml 0.5% bupivacaine in 8% dextrose via a 26-gauge needle with the patient in the left lateral position. Onset time was rapid in both groups and the distribution of maximum ascent of sensory analgesia was T1-T6. Efficacy of analgesia was greater in the bupivacaine group, although the duration of both sensory and motor blockade was shorter than following cinchocaine. There were no significant differences between the two groups either in the incidence and severity of complications or in the condition of the neonates. The high incidence (50-65%) and often profound extent of hypotension seen throughout the trial, confirm the ineffectiveness of crystalloid preload of 1500 ml as a single prophylaxis against hypotension.     

Awareness during Caesarean section

Between 1982 and 1989 over 3000 patients were questioned about recall and dreaming after general anaesthesia for Caesarean section. Some 28 (0.9%) patients were able to recall something of their operation and 189 (6.1%) reported dreams. There was uniform adherence to a rigid anaesthetic protocol up to and including 1985, but a much publicized incident reported from the courtroom stimulated a relaxation of this regimen. Consequently the incidence of awareness decreased from 1.3% to 0.4%, and the incidence of dreaming was also reduced. Recollections of surgery were confined to manipulations, noises and voices. None of our patients complained of pain at the time of interview, although one since has. The inadequacies of the initial protocol and an approach to informed consent are discussed.     

Antacid therapy for emergency Caesarean section

One hundred patients undergoing emergency Caesarean section were treated with cimetidine 200 mg intramuscularly when the decision was made to deliver the patient by Caesarean section and, preceding general anaesthesia, 30 ml of 0.3 M sodium citrate was administered orally. No routine antacid therapy was employed during labour. No patient had a gastric aspirate pH of less than 2.7, and only one of less than 3. The regimen is simple and effective, and treats only those patients at risk of acid aspiration.     

Recurrent anaphylactoid reaction during Caesarean section

A 28-year-old woman presented for emergency Caesarean section at 31 weeks' gestation with deranged liver function and a history of recurrent anaphylactoid reactions during previous pregnancy-related anaesthetics. The anaesthetic management and outcome of this case is presented.     

Detecting awareness during general anaesthetic Caesarean section An evaluation of two methods

Seventy-four patients received general anaesthesia for Caesarean section. Seven percent of the elective group and 28% of the emergency patients reported dreaming or recall of voices during the procedure (p less than 0.05) at postoperative interview. One patient from each group reported feeling pain or suffocation. All patients were monitored for awareness using the isolated forearm technique and lower oesophageal contractility. Provoked lower oesophageal contractility was the most effective of the different indices. A value greater than 35 mmHg on at least one occasion had a false negative rate of 33%, a false positive rate of 28% and a predictive value of 25%. A value greater than 13 mmHg picked up all patients who dreamed, with a false positive rate of 68%. Both of the 'aware' patients had provoked lower oesophageal contractility response of greater than 70 mmHg, an attribute shared by only 8% of the rest. The isolated forearm was particularly ineffective.     

The Bain, ADE, and Enclosed Magill breathing systems A comparative study during controlled ventilation

The Enclosed Magill, Humphrey ADE and the Bain breathing systems are all used for controlled ventilation of the lungs. This study compares the three systems in vitro with a lung model and in clinical practice. No difference was observed, with ventilatory variables commonly used in clinical practice, between the Bain and the ADE, while significantly lower end-tidal carbon dioxide values were observed with the Enclosed Magill (about 7%). Lower fresh gas flows can be used under these circumstances to maintain normocapnia with the Enclosed Magill than either the Bain or the Humphrey ADE.     

The reduction of amnesic wakefulness during Caesarean section

Wakefulness during general anaesthesia was assessed by the isolated forearm technique in two groups of patients for Caesarean section. The anaesthetic was based on the use of oxygen 66%, nitrous oxide 33% and halothane 0.4% during the induction delivery interval. There was a highly significant reduction in wakefulness in the Group who received nitrous oxide at 66% for the first 3 min only. The wakefulness was amnesic in all cases.     

Premedication for elective Caesarean section

Four coded, but otherwise unidentified, premedicants were prescribed in randomised order for 219 patients who were to undergo elective Caesarean section. Seventy-six (35%) of these patients affirmed at the pre-operative visit that they were not anxious. Diazepam 5 mg and lorazepam 1 mg appeared to be superior to the placebo and to 10-6 ml of 90% alcohol in inducing calmness and/or drowsiness, although the differences were not statistically significant. The incidence of awareness or unpleasant dreams was considerably higher in the placebo and alcohol series (6.2% and 7.5%) than in the diazepam and lorazepam series (nil and 2.1%). There was no remarkable difference in the condition of the immediate newly-born related to the premedicant received by the mother, any small differences being much less impressive than that related to the duration of the U-D interval. No notable differences were observed in the long term conditions between the infants in the placebo, alcohol and diazepam series but the incidence of "reluctance to feed". If relief from preoperative anxiety-and possibly a reduction in the likelihood of awareness-without undue effect upon the infant is considered desirable, diazepam 5 mg is the preferred choice from the four drugs investigated.