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Background There is no consensus about the best way to teach fiberoptic intubation. This study assesses the effectiveness of a training program in which novice anesthetic residents routinely were taught fiberoptic tracheal intubation of anesthetized, paralyzed, apneic patients. Methods Eight inexperienced anesthetic residents learned fiberoptic and conventional tracheal intubation simultaneously during their first 4 months of training. All intubations were performed using general anesthesia and muscle paralysis. Of these intubations, 223 (23%) were fiberoptic and 743 (77%) were laryngoscopic. Subsequently, their intubation skills with the two techniques were studied in a prospective, single-blind randomized trial involving 131 elective patients. Intubation times, SpO2, ETCO2, hemodynamic changes on intubation, and complications were recorded for 71 fiberoptic and 57 laryngoscopic intubations. Results There were two failures of the rigid and one failure of the fiberoptic technique due to inability to intubate within 180 s. In cases of failure, the tracheas were intubated successfully after mask ventilation by the alterative technique. No hypoxemia or hypercarbia occurred in any patient. There were no differences in hemodynamic indexes nor incidence of sore throat or hoarseness between the two groups. Mean intubation times were 56 +/- 24 s (mean +/- SD) for fiberoptic and 34 +/- 10 s (mean +/- SD) for laryngoscopic (P < 0.001). Conclusions Novices taught fiberoptic intubation and rigid laryngoscopic intubation under similar conditions, with similar volumes of experience, learn both techniques well. The safety and effectiveness of this training regimen commend it for inclusion in any residency program.

Hysteroscopy has become a widely accepted technique in the diagnosis and treatment of various gynaecological conditions. The advent of the fibreoptic endoscope and distending media has largely been responsible for the increasing use of hysteroscopy. It is our aim in this article to review the literature on the frequently used distending media such as carbon dioxide, glycine, dextran, dextrose, sorbitol and mannitol and their anaesthetic implications.The endoscopist chooses the particular medium. Complications due to the distending media occur in4% of cases. Dilutional hyponatraemia and hypothermia are commonly encountered complications and, in addition, hyperglycaemia and volume expansion can occur. Less commonly encountered complications are embolism with carbon dioxide and pulmonary oedema, renal failure and in rare cases anaphylaxis and encephalopathy. Regional anaesthesia may offer an advantage over general anaesthesia in early recognition of fluid accumulation. Apropriate monitoring should include fluid balance, routine monitoring as well as temperature, electrolytes and blood sugar measurements. Precordial Doppler measurement, central venous and/or pulmonary artery pressure measurement may be of help in detecting as well as treating carbon dioxide and/or air embolism and fluid balance in high risk patients.There is no one commonly used medium and no one medium is devoid of complications. There have been no controlled studies comparing different anaesthetic techniques. Positioning of the patient can give rise to complications such as peripheral neuropathy. Hysteroscopy is a non invasive procedure which entails a short hospital course with minimal postoperative sequelae and may be cost saving.

To assess the safety and efficacy of ritodrine and nitroglycerin for uterine relaxation during cesarean section with a breech-presenting fetus, performed under nongeneral anesthesia.A retrospective review of all breech singletons delivered by cesarean section under epidural anaesthesia in a two-year period. The study groups consisted of those who received ritodrine and those who received nitroglycerin. A group who received no relaxant served as a comparison group. The interval from uterine incision to delivery was recorded, and comparisons for potential complications of the medications included maternal changes in pulse and blood pressure, blood loss, and changes in hemoglobin and hematocrit. Fetal outcomes that were evaluated included five-minute Apgar score, cord pH and any recorded birth trauma. Statistical significance was set at P = .05. The Student t test, Yates's correlation for chi 2, Fisher's exact test and ANOVA were used as appropriate.The three groups had similar demographic characteristics. There was no significant difference in the uterine incision to delivery interval between the groups. In three cases the uterine incision to delivery interval was prolonged (5 minutes) in the nitroglycerin group, six cases in the ritodrine group and three in the comparison group (P = .002). There was no case of serious maternal morbidity or mortality, and no patient required a blood transfusion. The three groups had similar estimated blood loss, changes in maternal heart rate and systolic blood pressure intraoperatively and fall in hemoglobin and hematocrit 24 hours postoperatively. Neonatal outcome was similar among the three groups, and there was no case of neonatal birth trauma or intrapartum death. Cord blood analysis was similar in the three groups. One of the seven infants weighing1,500 g died within one hour of birth.Ritodrine and nitroglycerine are safe agents for use at cesarean breech delivery with epidural anesthesia and may be considered for uterine relaxation when a traumatic delivery is anticipated or encountered. Our results do not support the use of these tocolytics for "routine" cesarean breech delivery.

Nitroglycerin (NTG) has been demonstrated to provide uterine relaxation in the management of various obstetric complications. A 32-yr-old woman presented 40 min postpartum for manual removal of a retained placenta. Repeated, alternating doses of NTG 250 micrograms and syntocinon (SYN) 10U iv were used over 15 min to produce periods of uterine relaxation and contraction respectively for uterine exploration. Multiple attempts to extract the placenta failed and a diagnosis of placenta accreta was made. There were no major side effects from this combination of drugs apart from a transient 20% decrease in blood pressure after NTG, which responded to ephedrine 10-15 mg iv. The rapid change in uterine tone was believed to be due not only to the short duration of action of NTG and SYN, but also to the possible physiological antagonism between the two drugs. The mechanism of interaction may involve calcium mobilization and myosin light chain phosphorylation. We conclude that NTG and SYN can be used to produce alternating periods of uterine relaxation and contraction rapidly and consistently with little sustained effects from either agents.

A 29-yr-old patient was diagnosed with acute intermittent porphyria (AIP) during pregnancy. She had a Caesarean section under lidocaine/fentanyl epidural blockade. Because of inadequate analgesia, general anaesthesia was induced with propofol. Postoperatively urinary porphobilinogen excretion (625 μmol · day−1) exceeded the upper limit of normal but no symptoms of porphyria developed. In anecdotal clinical reports and in a previously described rat model of porphyria, propofol was found to be safe. This is the first reported use of propofol in a pregnant porphyric patient. Anaesthetic drug safety in porphyria is reviewed and the choice of induction agent discussed. Data on which to base these decisions is limited but we conclude that propofol may be suitable for use in patients with porphyria.

Epidural catheter insertion may be associated with blood vessel trauma or nerve root irritation. The purpose of this study was to assess whether the injection of small amounts of fluid through the Tuohy needle prior to catheter insertion reduced the incidence of these and other minor complications. Two hundred patients in labour, requesting epidural analgesia, were randomly assigned to one of three groups: Group I —the catheter was inserted without previous injection of fluid; Group II —3 ml, 1.5 per cent lidocaine hydrochloride was injected through the needle prior to catheter insertion; Group III —3 ml, saline was injected prior to catheter insertion. There were no differences among the groups in the incidence of blood vessel trauma or paraesthesiae. We conclude that there is no advantage in injecting of fluid routinely into the epidural space prior to catheter insertion.

The influence of anesthetic technique (general [GA] versus epidural [EPI]) on neonatal outcome was assessed for singleton infants of gestational age 32 wk or less, delivered by cesarean section. Neonates were identified from a prospectively collected perinatal database from 1986 to 1991. The independent effect of anesthetic technique on low 1-min Apgar scores after controlling for other risk factors was assessed by ordinal logistic regression. Among the 509 infants studied, 30% had Apgar scores of 0 to 3 at 1 min and 5.9% at 5 min. Among infants delivered with GA, 46.4% had low 1-min and 10.1% had low 5-min Apgar scores as compared to 22.0% and 3.8% for EPI. GA as compared to EPI was associated with higher risk of low (0-3) 1-min score after controlling for confounding factors (relative odds = 2.92, [1.99, 4.27 95% confidence intervals]). Other factors significantly related to low 1-min Apgar scores included malpresentation, maternal diabetes, primiparity, low gestational age, and associated neonatal outcomes (presence of respiratory distress syndrome and intraventricular hemorrhage). When there is a choice to be made in cesarean delivery of the premature infant, EPI is associated with higher 1- and 5-min Apgar scores compared to GA.

The effect of high-protein meal on the hepatic clearance (ClH) of intravenous lidocaine, because of its conceptual importance in understanding first-pass metabolic phenomena, was evaluated in nine healthy males. Our randomized crossover study demonstrated that mean ClH rose from 1245 to 1477 ml/min (P less than 0.03) as a result of the meal (i.e., mean area under the blood concentration-time curve decreased 20%). The magnitude of the change in clearance correlated weakly with fasting ClH (r = 0.54; slope = -0.037% per ml/min; intercept = 67.2%; P less than 0.15). In a separate study, it was observed that the meal did not influence lidocaine serum protein binding; the free fraction of lidocaine in samples drawn from the subjects in the fasting state averaged 0.305 +/- 0.027 while that from subjects who had eaten was 0.321 +/- 0.042. These data suggest that the mean clearance of lidocaine is increased by stimulation of hepatic blood flow rate. Furthermore, the magnitude of this increase is consistent with expectations based on a simple physiologic model. Thus, these data provide experimental support for the hypothesis that transient increases in splanchnic blood flow rate observed after a high-protein meal may explain apparent improvement of the oral bioavailability of model high intrinsic clearance drugs.

Because maternal stress may adversely affect the fetus, the authors tested the effects of brief episodes (15-60 sec) of maternal stress in 18 awake pregnant ewes. Maternal agitation and stuggling occurred either following non-painful stimuli such as loud noises or sudden movements of personnel (ten animals) or following the brief application of the ewe's skin of a uniform electrical stimulus of 30 volts with a frequency of 167 Hz for 30-60 sec (eight animals). Stimulation of either type produced a 45-50 per cent increase in mean maternal arterial blood pressure and a concomitant 32-52 per cent decrease in uterine blood flow (P less than 0.05). The decreases in uterine blood flow were brief, lasting less than 3 min, and were not associated with fetal asphyxia. Maternal plasma norepinephrine levels were measured following electrically induced maternal stress and were increased 25 per cent. The authors conclude that maternal stress may decrease uterine blood flow secondary to release of endogenous norepinephrine.

Four case histories are presented to illustrate that haemodynamic monitoring is a useful guide in the acute management of severe pre-eclampsia and eclampsia. The application of intensive monitoring and therapy to patients in the delivery room is both feasible and of great help to the clinician managing fluid therapy and/or anaesthesia.

In seven pregnant ewes, 3--5 min of hypotension resulting from spinal anesthesia decreased uterine blood flow 17 per cent. Dopamine, in doses sufficient to maintain blood pressure at control values (20--40 micrgram/kg/min) for 3--5 min, further decreased uterine blood flow to 56 per cent less than control and increased uterine vascular resistance to 50 per cent more than control. Following 30 min of hypotension, 30 min of dopamine administration in doses sufficient to restore blood pressure to control values (5--20 microgram/kg/min) similarly decreased uterine blood flow to 29 per cent less than control and increased uterine vascular resistance to 35 per cent more than control.

A randomized double blind placebo controlled study of the efficacy, duration and safety of epidural morphine for the management of pain after Cesarean section is reported. Three similar groups of patients received either 0, 4 mg or 8 mg of morphine sulphate in 10 ml of normal saline through an epidural catheter at the completion of the operation. Compared to the saline controls, both the 4 mg and 8 mg epidural morphine groups had significant pain relief as judged by an analogue pain scale (p less than 0.001), the time to the first administration of narcotic analgesics (p less than 0.001) and the amount of supplemental analgesic required in the first 36 hours after operation (p less than 0.001). The side effects occurred in a dose-dependent fashion. Two patients who received epidural morphine 8 mg plus additional narcotic or antihistamine had reduced respiratory rates but were easily rousable. Our experience suggests that the epidural administration of morphine 4 mg may be a safe and reliable method of obtaining prolonged analgesia following Caesarean section.

The purpose of this study was to compare two epidural catheters--the Portex epidural catheter and Vas-Cath catheter. One hundred and fifty patients in labour who received epidural anaesthesia were selected and either one or the other catheter was used, based on random assignment. Ease of insertion, maintenance and removal of the catheter were assessed, as was the incidence of blood return and paraesthesiae during epidural catheter insertion. There were no significant differences between the catheters as far as insertion, maintenance and removal were concerned. However, the incidence of paresthesiae was 44 per cent with the Portex and 24 per cent with Vas-Cath catheters (p less than 0.008). The incidence of blood vessel trauma was 12 per cent with the Portex and 6.7 per cent with the Vas-Cath catheter (p = NS). Choice of epidural catheter is a factor to be considered in minimizing the incidence of blood vessel trauma or paresthesiae.

Doppler ultrasound has recently been used to assess changes in blood velocity in the uterine and umbilical arteries. Alterations in the ratio of systolic to diastolic velocity (S/D ratio) are believed to reflect changes in placental vascular resistance. We have used this technique to assess potential beneficial or detrimental effects of epidural anaesthesia on blood flow to the placenta. Continuous wave Doppler ultrasound was used to measure the S/D ratio in the uterine and umbilical arteries of 12 patients undergoing epidural anaesthesia prior to elective caesarean section. Anaesthesia was achieved using lidocaine and epinephrine. The S/D ratio in both the uterine and umbilical arteries remained unaltered either by the fluid preload or by the epidural anaesthesia. It is concluded that epidural anaesthesia using this technique has neither a beneficial nor detrimental effect on uterine or umbilical blood velocity in the uncomplicated pregnancy.

A questionnaire was designed to determine the type of personnel that provide obstetrical anaesthesia care and the techniques used in the provision of this care. All seven hospitals with an obstetrical unit affiliated with the University of Toronto and seven community hospitals responded. All anaesthetics were given by physicians. Ninety-two per cent of those in University affiliated hospitals and 63 per cent of those in the community hospitals had obtained their specialty qualification. Standards for preoperative assessment and communication with the patients should be similar to those applied to patients receiving anaesthesia for other reasons. It was clear from our survey that pre-anaesthetic assessment of obstetrical patients differs from that advocated for other surgical patients. For vaginal deliveries, epidural analgesia was clearly the preferred choice, Subarachnoid block was rarely used. The majority of anaesthetists did not use a test dose. Eleven per cent in University-affiliated hospitals and 50 per cent in community hospitals sometimes conducted surgical anaesthesia without tracheal intubation for vaginal delivery. More than 60 per cent routinely encouraged their patients to accept general anaesthesia for Caesarean section. The doctors providing neonatal resuscitation may require further training. Surveys such as this are important if standards of anaesthetic practice are to be established.

The effect of lateral positioning and the volume of drug injected on the spread of epidural anaesthesia was assessed in 131 healthy parturients. Epidural injection for anaesthesia was done at the L3-4 interspace and a catheter was inserted into the epidural space after injection of the drug. The patients were randomly assigned to four groups. The doses used were 12 ml of bupivacaine 0.25 per cent and 6 ml of bupivacaine 0.5 per cent. Patients were kept in the lateral position in which the block was done (Groups I and III) or turned to the opposite side after completion of the epidural injection (Groups II and IV). Sensory levels and maternal assessment of pain relief were determined fifteen to twenty minutes after injection. All assessments were done by a trained observer who did not know to what group the patient had been allocated. Maintenance of the lateral position after induction of epidural anaesthesia is compatible with satisfactory analgesia for labour. Twelve ml bupivacaine 0.25 per cent provides better analgesia than 6 ml bupivacaine 0.5 per cent although the same mass is injected. The quality of analgesia is improved by turning the patients to the contralateral side after injection of 12 ml bupivacaine 0.25 per cent.

One must distinguish between what is medically safe and what is legally safe. The authors have the impression that in order to be "legally safe" one must perform a test dose. This is despite the fact that it has not been conclusively shown that the use of test doses improve the safety margin of epidural anaesthesia, when administered by a competent person, with the proper resuscitative equipment immediately available. Until a controlled study is performed, test doses should be done for continuous epidural anaesthesia with the understanding that they are neither 100 per cent sensitive nor specific in preventing complications. It is however one more manoeuvre that may be useful in recognizing some of the patients with accidental subarachnoid placement of epidural catheters. The literature suggests that lidocaine 1.5 per cent in dextrose 7.5 per cent should be the test dose of choice in obstetric epidural anaesthesia in an amount known to produce spinal anaesthesia (30-50 mg). The use of epinephrine in test doses in unpremedicated healthy women in active labour is neither sensitive nor specific in signalling intravascular injection, and it may also be detrimental to fetal wellbeing. Epinephrine 15 micrograms as a test dose for intravenous injection appears to create more problems than it solves.

The safety of epidural anaesthesia in patients with active, recurrent genital herpes simplex (HSV) infections is controversial. We reviewed the six-year experience of the use of epidural anaesthesia in this patient population in two institutions. Eighty-nine parturients with active genital HSV were administered epidural anaesthesia for Caesarean section. No patient suffered an adverse outcome related to either the anaesthetic or the virus. The theoretical risks of regional anaesthesia in the parturient with active herpes genitalis are reviewed. We conclude from available data that the risk of an adverse outcome is small and does not contraindicate the use of epidural anaesthesia in patients with recurrent infection.

The effect of lateral positioning and the volume of drug injected on the spread of epidural anaesthesia was assessed in 131 healthy parturients. Epidural injection for anaesthesia was done at the L3-4 interspace and a catheter was inserted into the epidural space after injection of the drug. The patients were randomly assigned to four groups. The doses used were 12 ml of bupivacaine 0.25 per cent and 6 ml of bupivacaine 0.5 percent. Patients were kept in the lateral position in which the block was done (Groups I and III) or turned to the opposite side after completion of the epidural injection (Groups II and IV). Sensory levels and maternal assessment of pain relief were determined fifteen to twenty minutes after injection. All assessments were done by a trained observer who did not know to what group the patient had been allocated. Maintenance of the lateral position after induction of epidural anaesthesia is compatible with satisfactory analgesia for labour. Twelve ml bupivacaine 0.25 per cent provides better analgesia than 6 ml bupivacaine 0.5 per cent although the same mass is injected. The quality of analgesia is improved by turning the patients to the contralateral side after injection of 12 ml bupivacaine 0.25 per cent.

The effects of enflurane analgesia (approximately 0.5%) were studied in 55 patients during the second stage of normal vaginal delivery and were compared with effects of nitrous oxide (approximately 40%) in 50 similar patients. The enflurane and oxygen mixture was rated satisfactory by 89% of the mothers and 80% of the anesthesiologists. These ratings did not differ significantly from those for nitrous oxide. Obstetricians, however, rated the enflurane and oxygen mixture superior. The newborns of mothers receiving both agents wee vigorous and comparable when assessed by Apgar scores and cord blood gas tensions. The estimate of blood loss was similar in both groups. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly increased from preanesthetic levels with either agent. There was no biochemical evidence of renal toxicity. In neonates of mothers given enflurane, the mean umbilical cord concentration of serum inorganic fluoride ions was 2.4 +/- 0.2 micromoles/L, a value well below that associated with nephrotoxicity.

Three pregnant patients with myasthenia gravis are presented and anesthetic considerations discussed. The course of myasthenia gravis is highly variable and unpredictable during pregnancy. Anticholinesterase therapy should be maintained during labor, and the IM route of administration is preferred. Exacerbations very often occur in the immediate postpartum period. Regional anesthesia is preferred for vaginal delivery. In the case of cesarean section, general anesthesia may be preferable. Neonatal myasthenia gravis is a transient syndrome that appears in 20 to 30% of the newborns of myasthenic mothers.