Local application of EMLA and glyceryl trinitrate ointment before venepuncture.

One hundred unpremedicated fit day surgery patients aged between 27 and 68 years were allocated randomly into one of four groups and EMLA, glyceryl trinitrate, EMLA and glyceryl trinitrate or a placebo ointment was applied to the dorsum of a hand. The pain and ease of venepuncture were determined at induction of anaesthesia 60 minutes later. Pain scores were also reassessed 1-2 hours after operation. Lower pain scores and easier venepuncture occurred when EMLA and glyceryl trinitrate ointment was applied to the dorsum of the hand.

Cryoanalgesia for pain after herniorrhaphy.

The effect of freezing the ilioinguinal nerve on postoperative pain relief was examined in a double blind study in 36 patients undergoing herniorrhaphy, randomly allocated into two groups. Patients in the experimental group had their ilioinguinal nerves frozen during surgery and were compared with the patients in the control group who did not have cryoanalgesia. Pain relief was assessed over a 48-hour period in three ways, namely the linear analogue pain scale, peak expiratory flow rates and the amount of analgesic drugs required by patients in the two groups. We conclude that cryoanalgesia of the ilioinguinal nerve alone does not produce significant early post herniorrhaphy pain relief.

Continuous subcutaneous pethidine for routine postoperative analgesia.

We consider that the present state of postoperative analgesia is unsatisfactory because drugs are given intermittently and usually only at the patients' request and with nurses' acquiescence. A procedure for routine continuous pethidine infusion, suitable for administration and control by the nursing staff is described. The results of a trial on patients after major surgery are summarised. We believe the procedure to be more efficient and effective than those presently in use.

The prolongation of local anaesthetic action with dextran. The effect of molecular weight.

Field blocks of the inguinal region were performed in two groups of patients, in one group using a mixture of 0.5% bupivacaine, 1:200 000 adrenaline and dextran 110 and in the second group using a mixture of 0.5% bupivacaine, 1:200 000 adrenaline and dextran 150; the study being performed in a double-blind fashion. The dextran 150 mixture produced a highly significant increase (p less than 0.01) in the duration of the block when compared with the dextran 110 mixture. The authors conclude that the use of dextran of increasing molecular weight increases the duration of action of local anaesthetics correspondingly.

Lumbar epidural injections in the treatment of sciatica.

A randomized trial of lumbar epidural injections for the treatment of acute sciatic pain was carried out. All the patients had unilateral sciatica for less than six months and had never previously been treated in hospital for their backs. The treatments used were 20 ml normal saline, 80 mg Depomedrone in normal saline made up to 20 ml, 20 ml, 20 ml 0.25% bupivacaine solution and needling with a standard Touhy injection needle into the interspinous ligament but with no injection. The patients improved at about the same rate for all four treatments. Overall, 75% of the patients improved or were cured. As some of these were in the group treated by needling of the interspinous ligament, it seems likely that the epidural injections administered achieved effects partially as a placebo and partially by virtue of the natural history of the acute sciatic syndrome.

Ventilatory response to morphine in young and old subjects.

The effects of intravenous morphine (10 mg/70 kg body weight) on ventilation in two groups of subjects, young (age 28-37 years) and old (age 65-82 years) were studied prior to elective surgery. There was no significant difference between the two groups in minute ventilation, ventilatory frequency and end-tidal carbon dioxide before morphine administration. In both groups there was a significant depression of ventilation and elevation of end tidal carbon dioxide tension 20 minutes after intravenous morphine. There was no significant difference between the two groups in the response of these variables to morphine. However, in the older group seven out of thirteen subjects showed frequent periods of apnoea or periodic breathing whereas three of the young subjects had these phenomena at much less frequent intervals. Respiratory depression after morphine is similar in old and young patients but old patients have more change in ventilatory control.

A study of pethidine kinetics and analgesia in women in labour following intravenous, intramuscular and epidural administration.

1 Epidural administration of opiates for analgesia has recently generated widespread interest and would theoretically be advantageous as a method for relief of pain in labour. 2 Plasma pethidine concentrations were measured after intravenous, intramuscular and epidural administration of pethidine to women in labour and after epidural administration to non-pregnant female surgical patients. 3 Kinetic parameters were derived from the plasma concentration data in each group of subjects and the relationship between plasma kinetics and analgesia in labour were examined. 4 Absorption of pethidine from the epidural space in pregnant women in rapid and excepting the lower initial values, the average plasma concentration and area under the plasma concentration v time curve did not differ significantly (P less than 0.01) from those obtained with intravenous dosage, but were significantly higher (P less than 0.01) during the first 2 h after dosage than the results after intramuscular administration. The analgesia provided by the epidural route of administration was greater than with intravenous or intramuscular administration. 5 It is postulated that the analgesic efficacy of epidural pethidine in women in labour is due to a combination of systemic and local effects and that the local effect is attributable to the local anaesthetic properties of pethidine rather than a selective anti-nociceptive action on the spinal cord.

Comparison of epidural and intramuscular pethidine for analgesia in labour.

Analgesia mediated by a direct spinal action of narcotic drugs administered via the epidural route may have considerable advantages over conventional(conduction block) epidural analgesia in labour. The efficacy, mode of action and placental transfer of epidurally administered narcotics in labour has not yet been established. We have compared the systemic absorption, analgesia and other effects on the mothers and transfer of drug to the fetus in primigravidae who received epidural or intramuscular pethidine 100 mg in labour. The superior analgesia following epidural pethidine did not appear to be attributable to a selective spinal action but rather to higher plasma concentrations of pethidine together with a possible weak regional conduction block due to local anaesthetic action of 1% pethidine solution. Epidural pethidine is not an advantageous method for providing analgesia in labour.

Prophylaxis for Mendelson's syndrome before elective caesarean section. A comparison of cimetidine and magnesium trisilicate mixture regimens.

A clinical trial was conducted in which patients undergoing elective Caesarean section received eitherrr oral cimetidine 400 mg or magnesium trisilicate mixture BPC 20 ml before anaesthesia. The pH values of gastric fluid were significantly higher and the incidence of pH less than 2.5 was significantly lower in patients who received magnesium trisilicate mixture BPC. No adverse effects were observed in newborn infants whose mothers had received cimetidine and there was no significant difference in pH values of gastric fluid from the newborn in the two groups. The findings suggest that as a means of prophylaxis for Mendelson's syndrome in patients undergoing elective Caesarean section, magnesium trisilicate mixture BPC 20 ml is more effective than a single oral dose of cimetidine 400 mg, administered in the manner described.

Occupational exposure to anaesthetics in 20 hospitals.

The nitrous oxide and halothane contamination in the inspired air of anaesthetists and in the atmospheres of operating theatres, anaesthetic induction and recovery rooms, were measured during normal unmodified working sessions in 20 hospitals using integrated personal samplers. The nitrous oxide (and halothane) levels ranged from < 10 to 3000 ppm (< 0.1 to 60 ppm) in the different areas with an average of 388.5 ppm (2.8 ppm) for the inspired air of the anaesthetists during 2 hour sampling periods. There was no correlation between the levels of the anaesthetists' exposures and those in the static air samples and this appeared to be due primarily to a wide variation in work practices and techniques. Thus it is potentially misleading to assess anaesthetists' occupational exposure by collecting ambient air samples in the operating rooms. Comparisons with more prolonged measurements in one hospital indicated that the installation of relatively simple active scavenging devices will be effective in most hospitals.

Failure of epidural morphine to relieve pain in labour.

Lumbar epidural injections of 2 mg preservative-free morphine were given to 10 subjects in established labour. Assessment of pain using a visual analogue scoring system revealed no appreciable relief of pain 30 min after morphine infection. Analgesia was subsequently provided by epidural injection of 8 ml bupivacaine 0.375%. Failure of epidural 2 mg in the treatment of severe pain other than labour. Possible explanations for this discrepancy are discussed.

The anaesthetic machine--a study of function and design.

A study of the time and motion of the anaesthetists' routine activities was made using conventional equipment. Films of manual and visual movements were studied in detail and the expectations of certain consultant anaesthetists regarding apparatus were recorded. Models of apparatus were used to test their acceptability. A modular system appeared preferable to a work station or to adaptation of present designs. More work and the construction of prototypes are indicated if the anaesthetic machine is to be modernized.