Intrathecal midazolam reduces isoflurane MAC and increases the apnoeic threshold in rats

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - The purpose of this study was to examine the anaesthetic requirement of intrathecal midazolam in a dose-response fashion in...     

Prophylactic administration of histamine1 and histamine2 receptor blockers in the prevention of protamine-related haemodynamic effects

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - We studied the effects of the prophylactic administration of histamine1 and histamine2 receptor blockers on haemodynamic...     

Bain circuit occluded by foreign body

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - The purpose of this report is to describe a potentially hypoxic event which occurred during mask induction with the Bain...     

Oral premedication for paediatric ambulatory anaesthesia: a comparison of midazolam and ketamine

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - To compare the clinical characteristics of two oral premedicants, midazolam and ketamine, 40 healthy children, one to six...     

Haemodynamic consequences of warm cardiac irrigation during cardiac surgery

Canadian Journal of Anesthesia/Journal canadien d'anesthésie - Following cardiopulmonary bypass (CPB) and prior to closing the chest, some surgeons irrigate the heart and pericardium with...     

The evolution of anaesthesia as a specialty in Canada

Since 1847 anaesthesia in Canada has evolved through six phases. In the first (1847-1898), it was a craft without an academic and professional base. The second (1899-1919) was marked by the first academic appointments and by Canadians' wartime experiences of anaesthesia. The third phase (1920-1929) evidenced the professional satisfaction of anaesthesia and included the founding of the Canadian Society of Anaesthetists. In the fourth phase (1930-1943) the growth of the Royal College of Physicians and Surgeons of Canada, the introduction of certification and the founding of the definitive professional society--the Canadian Anaesthetists' Society--fostered the evolution of what was now becoming a recognizable specialty. The fifth phase (1944-1971) was one of resolution of problems affecting the status of anaesthesia: the first autonomous department of anaesthesia in a Canadian university was founded (at McGill in 1945), the Royal College Fellowship was approved for anaesthesia (in 1951), the Canadian Anaesthetists' Society Journal was launched (in 1954) and a single standard for certification of specialists was finally established (in 1971). In the sixth (1972-1989), the main elements were the assumption of responsibility for residency training by the universities and by the renaming of the journal as the Canadian Journal of Anaesthesia. Through these years of increasing professionalism, it has, however, been the accomplishments of individual Canadian physicians, facing many challenges, that have made the specialty in Canada recognizably Canadian.     

Mechanical obstruction to ventilation from an ovarian cyst during pregnancy

This report documents the danger of the gravid utérus fixing a large ovarian cyst in a position disadvantageous to diaphragmatic excursion and thereby obstructing ventilation. A 34-year-old pregnant patient presented at 18 weeks amenorrhoea with a large ovarian cyst. She gave a history of exertional dyspnoea and orthopnoea. Clinical examination revealed a grossly enlarged abdomen and a respiratory rate of 28 breaths · min^?1. Intraoperatively, ventilation was markedly impaired resulting in cyanosis and bradycardia. This was relieved by drainage of the ovarian cyst. A left lateral tilt with manual traction on the tumour may have avoided this problem. Should the above measures be inadequate, immediate drainage of the cyst is essential. Severe respiratory distress may require ultrasoundguided, percutaneous, aspiration of the cyst preoperatively. However, as in this patient, the absence of gross signs of respiratory failure does not preclude acute ventilatory failure after induction of anaesthesia.     

Regional anaesthesia for hernia repair in children: local vs caudal anaesthesia

The purpose of this study was to compare the effect of local anaesthesia (LA) with that of caudal anaesthesia (CA) on postoperative care of children undergoing inguinal hernia repair. This was a randomized, single-blind investigation of 202 children aged 1–13 yr. Anaesthesia was induced with N₂O/O₂ and halothane or propofol and maintained with N₂O/O₂/halothane. Local anaesthesia included ilioinguinal and iliohypogastric nerve block plus subcutaneous injection by the surgeon of up to 0.3 ml · kg^?1 bupivacaine 0.25% with 5 μg · kg^?1 adrenaline. The dose for caudal anaesthesia was 1 ml · kg^?1 up to 20 ml bupivacaine 0.2% with 5 μg · kg^?1 adrenaline. Postoperative pain was assessed with mCHEOPS in the anaesthesia recovery room, with postoperative usage of opioid and acetaminophen in the hospital, and with parental assessment of pain with a VAS. Vomiting, time to first ambulation and first urination were recorded. The postoperative pain scores and opioid usage were similar; however, the LA-group required more acetaminophen in the Day Care Surgical Unit. The incidence of vomiting and the times to first ambulation and first urination were similar. The LA-patients had a shorter recovery room stay (40 ± 9 vs 45 ± 15 min, P < 0.02). The postoperative stay was prolonged in the CA group (176 ± 32 vs 165 ± 26 min, P = 0.02). We conclude that LA and CA have similar effects on postoperative care with only slight differences.     

Patient-controlled analgesia following caesarean section under general anaesthesia: a comparison of fentanyl with morphine

This prospective, randomised, double-blind study compared PCA fentanyl with PCA morphine for post-Caesarean section analgesia. Following a standardised general anaesthetic, 37 women were allocated to receive either fentanyl (n = 18) or morphine (n = 19). The PCA was commenced after the women had been made comfortable in the postanaesthetic recovery room with the appropriate opioid solution (mean dose required = fentanyl 375 μg or morphine 16 mg). Initial PCA settings were bolus 1 ml (fentanyl 25 μg or morphine 1 mg), lockout time ten minutes, and no background infusion. Both analgesic solutions provided effective analgesia for a mean of 37 hr with high levels of patient satisfaction, and there were no differences in VAS scores for pain and patient satisfaction, or for side effects (nausea, itch, and sleepiness) between fentanyl or morphine. However, more patients in the fentanyl group required supplementary boluses or alterations to the PCA settings (13/18 vs 4/19: P = 0.005), and one patient was removed from the study due to inadequate analgesia. We conclude that fentanyl is not recommended for routine PCA use following Caesarean section. Cette étude randomisée et à double aveugle compare la PCA au fentanyl avec la PCA à la morphine pour l’analgésie postcésarienne. Après une anesthésie générate standard, 37 femmes sont réparties pour recevoir soil du fentanyl (n = 18) soil de la morphine (n = 19). La PCA est debutée à la salle de réveil des que les patientes se sentent confortables sous une solution appropriée de morphinique (dose moyenne requise, fentanyl 375 μg ou morphine 16 mg). Le régime initial consiste en un bolus d’un ml (fentanyl 25 μg ou morphine 1 mg), un intervalle de sécurité de dix minutes, sans perfusion continue. Les deux solutions produisent une analgésie satisfaisante pour 37 h en moyenne avec un degré élevé de satisfaction pour la patiente, et on ne note pas de différence entre le fentanyl et la morphine pour l’évaluation de la douleur par EVA, le degré de satisfaction, et pour les effets secondaires (nausée, prurit et somnolence). Cependant, plus de patientes sous fentanyl ont eu besoin de bolus supplémentaires ou des modifications aux réglages de la PCA (13/18 vs 4/19; P = 0,005). Une patiente est exclue de l’étude pour raison d’insuffisance d’analgésie. En conclusion, nous ne recommandons pas la PCA au fentanyl après la césarienne.

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Presented at the 1992 meeting of the Society for Obstetric Anesthesia and Perinatology (SOAP) in Charleston, South Carolina, USA.     

Contractile force and resting tension in the presence of halothane and increased extracellular potassium or decreased extracellular pH in isolated guinea pig atria

To gain a better understanding of the direct actions of halothane on myocardial function in ischaemia, we studied the effects of increasing extracellular potassium concentration and decreasing extracellular pH (acidosis), alone or in combination with halothane, on the contractile force and resting tension in isolated atria. Guinea pig left atria were superfused with Tyrode’s solution and stimulated at 1 Hz. Isometric contractile force and resting tension were measured using a force displacement transducer. Perfusate potassium concentrations were increased from 5.4 mmol · L⁻¹ to either 8.1 mmol · L⁻¹ or 10.8 mmol · L⁻¹ by adding KCl to the standard Tyrode’s solution, and its pH was decreased from 7.4 to either 7.0 or 6.5 by decreasing bicarbonate. In standard Tyrode’s solution (potassium 5.4 mmol · L⁻¹, pH 7.4), halothane 0.5–2% reduced contractile force in a dose-dependent manner (P < 0.05); the effective concentration of halothane for 50% inhibition of contractile force (IC₅₀) was 1.3%. Both increasing extracellular potassium and decreasing extracellular pH decreased the contractile force in a potassium-or pH-dependent fashion. The negative inotropism of halothane (1%) was not altered by increasing potassium concentrations, whereas 1% halothane caused a greater decrease in contractile force at pH 6.5 than at pH 7.4. Halothane (1%) enhanced the acidosis (pH 6.5)-induced increases in resting tension. Arrhythmias were produced in one of eight preparations during acidosis, while four of eight preparations demonstrated arrhythmias during acidosis in the presence of halothane. These data suggest that acidosis and halothane may have a synergistic interaction on the contractile force and resting tension of the atria. The increase in resting tension observed during acidosis/ halothane conditions suggests than an increase in cytosolic calcium is associated with these synergistic interactions between acidosis and halothane. Pour mieux comprendre l’action direct de l’halothane sur la fonction myocardique pendant l’ischémie, nous avons étudié les effets de l’augmentation du potassium extracellulaire et de la diminution du pH extracellulaire (acidose), seuls ou en association avec l’halothane, sur la force contractile et la tension de repos d’oreillettes isolées. Des oreillettes gauches de cobaye furent perfusées avec une solution de Tyrode et stimulées à 1 Hz. La force contractile isométrique et la tension de repos ont été mesurées avec un transducteur de force de déplacement. Les concentrations de potassium perfusées ont été augmentées de 5,4 mmol · L⁻¹ à 8,1 mmol · L⁻¹ ou à 10,8 mmol · L⁻¹ par l’ajout de KCl à la solution standard de Tyrode, et son pH abaissé de 7,4 à 7,0 ou 6,5 par baisse des bicarbonates. Avec la solution standard de Tyrode (potassium 5,4 mmol · L⁻¹, pH 7,4), l’halothane (0.5–2%) diminue la force contractile proportionnellement à la dose (P < 0,05); la concentration efficace d’halothane requise pour produire une inhibition de 50% de la force contractile (IC_5O) a été de 1,3%. L’augmentation du potassium extracellulaire et la diminution du pH extracellulaire réduisent toutes les deux la force contractile proportionnellement au potassium ou au pH. L’inotropisme négatif de l’halothane (1%) n’est pas modifié par l’augmentation de la concentration de potassium alors que l’halothane produit une diminution plus importante de la force contractile à un pH de 6,5 que de 7,4. L’halothane (1%) exagère l’augmentation de la tension de repos induite par l’acidose (pH 6,5). Des arrythmies sont apparues sur une des huit préparations pendant l’acidose en présence d’halothane. Ces données suggèrent que l’acidose et l’halothane pourraient avoir une activité synergique sur le force contractile et la tension de repos des oreillettes. L’augmentation de la tension de repos observée pendant l’acidose combinée à l’halothane suggère l’association d’une augmentation du calcium cytosolique avec des interactions synergiques entre l’acidose et l’halothane.     

Does hypothermia or hyperventilation affect enflurane MAC reduction following partial cardiopulmonary bypass in dogs?

This study in dogs determined the effect of systemic cooling and arterial hypocarbia during cardiopulmonary bypass (CPB) on the requirements for enflurane anaesthesia (MAC) before and after CPB. Twelve mongrel dogs were each anaesthetized with enflurane in oxygen on two separate occasions. End-tidal enflurane concentration was measured with a Puritan-Bennett Anaesthesia Agent Monitor. Using the tail-clamp method, MAC was determined twice with a one-hour interval between measurements (MAC 1 and MAC 2). Partial CPB was then initiated using femoral arterio-venous cannulation and maintained for one hour. Following separation from CPB, MAC was again determined twice with a one hour interval between measurements (MAC 3 and MAC 4). Dogs were randomly assigned according to PaCO₂ management during CPB (low, 17.6 ±8.6 mmHg vs high, 38.9 ± 11.5 mmHg), and then subjected to two experimental conditions. The first experiment on each dog was undertaken using normothermia during CPB (warm, 35–37° C) while the second experiment (at least two weeks later) was conducted using hypothermia during CPB (cold, 30° C). Analysis of the data, using ANOVA for repeated measures, revealed MAC 3 (1.95 ± 0.33%, post-CPB) to be reduced when compared with MAC 1 (2.18 ± 0.28%, P < 0.01) or MAC 2 (2.10 ± 0.22%, P < 0.01), determined before CPB. Multivariate repeated measures analysis revealed no independent effects of hypothermia or arterial hypocarbia during CPB, on MAC reduction. By the time of the second experiment in each dog (two weeks later), MAC had returned to baseline levels. The authors conclude that, in the dog, partial CPB causes a short-term small reduction of enflurane MAC, but that neither hypothermia nor hypocarbia during CPB affected MAC. Cette étude réalisée sur le chien vise à déterminer les conséquences du refroidissement systémique et de l’hypocarbie artérielle pendant la circulation extra-corporelle (CEC) et la concentration alvéolaire minimum de l’enflurane (MAC) avant et après la CEC. Douze chiens batards sont anesthésiés à deux reprises à l’enflurane dans l’oxygène. On mesure la concentration d’enflurane en fin d’expiration à l’aide d’un moniteur d’agent anesthésique Puritan-Bennett. Par la méthode du clampage de la queue du chien, la MAC est déterminée à deux reprises avec une heure d’intervalle entre chaque mesure (MAC 1 et MAC 2). Une CEC partielle est alors débutée par canule artério-veineuse fémorale et continuée pendant une heure. Après arrêt de la CEC, la MAC est de nouveau déterminée deux fois, toujours avec une heure d’intervalle entre les mesures (MAC 3 et MAC 4). Les chiens sont ensuite assignés au hasard selon le niveau de la PaCO₂ pendant la CEC (bos, 17,6 ±8,6 mmHg vs haut, 38,9 ± 11,5 mmHg), et ensuite soumis à deux conditions expérimentales. La première a lieu pour chacun des chiens sous normothermie sous CEC à 35°–37° C; la deuxième expérience réalisée au moins deux semaines plus tard, se tient avec une hypothermie sous CEC à 30° C. L’analyse des données par ANOVA pour les mesures répétées montre que MAC 3 (1,95 ± 0,33% après CEC) diminue lorsque comparée à MAC 1 (2,18 ± 0,28, P < 0,01) ou MAC 2 (2,10 ± 0,22%, P < 0,01), déterminée avant CEC. L’analyse statistique multifactorielle des données répétées ne démontre ni pour l’hypothermie, ni pour l’hypocarbie artérielle d’activité indépendante sur la réduction de la MAC pendant la CEC. Au moment de la deuxième expérience sur les chiens (deux semaines plus tard), la MAC revient aux mesures de départ. Les auteurs concluent que la CEC partielle provoque sur le chien une baisse à court terme de la MAC de l’enflurane mais que ni l’hypothermie, ni l’hypocarbie n’affectent la MAC sous CEC.

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Supported by The New Brunswick Heart and Stroke Foundation and The Maritime Heart Center. Dr. Doak is supported by the Nova Scotia Medical Research Fund. Dr. Hall is a PMAC/MRC Health Research Foundation Scholar.     

Consequences of fluid absorption during transurethral resection of the prostate using distilled water or glycine 1.5 per cent

This prospective and randomized study compared the consequences of two irrigating fluids, distilled water and glycine for transurethral prostatectomy. Forty-nine consecutive unselected patients undergoing transurethral resection of the prostate with spinal anaesthesia were investigated. The irrigating fluid was either distilled water (group A, 24 patients) or glycine 1.5 per cent (group B, 25 patients). The absorption of irrigating fluid was measured, all surgical events and any clinical signs of TURP syndrome during and after surgery were recorded. Early signs of TURP syndrome were observed in one patient in group A and in four in group B without further consequence. From all the biological variables, only plasma protein concentration, haematocrit, free plasma haemoglobin and free bilirubin concentrations were found to have changed. Plasma protein concentration and haematocrit decreased significantly during and after surgery in the two groups. Free plasma haemoglobin increased significantly with time: a significantly higher concentration was observed in group A than group B. Free bilirubin concentration increased with time in the two groups and was statistically greater in group A. With the two irrigating fluids, we observed a significant amount of haemolysis and haemodilution without clinical consequences. A low irrigating fluid pressure, a short resection time, and the use of spinal anaesthesia seems to us to be essential. Close observation of patients following transurethral prostatectomy is needed but the choice of the irrigating fluid does not seem to be important. Cette étude prospective et randomisée a comparé les conséquences de deux liquides d’irrigation, l’eau distillée et le glycocolle au cours de la chirurgie prostatique par voie basse. Quarante-neuf patients consécutifs, non sélectionnés, bénéficiant d’une résection transuréthrale de prostate sous rachianesthésie, sont étudiés. Le liquide d’irrigation est soil l’eau distillée (groupe A, 24 patients), soit le glycocolle à 1.5 pour cent (groupe B, 25 patients). L’absorption des liquides d’irrigation, les incidents chirurgicaux et les signes cliniques du syndrome de réabsorption sont systématiquement notés. Des signes caractéristiques du syndrome de réabsorption sont observés dans un cas dans le groupe A et dans quatre cos dans le groupe B sans conséquence ultérieure. Seuls la protidémie, l’hématocrite, l’hémoglobine plasmatique libre et la bilirubine libre changent significativement. L’hémoglobine plasmatique libre augmente significativement dans les deux groupes, avec un taux plasmatique significativement plus élevé dans le groupe A. Avec les deux liquides d’irrigation, on observe une hémolyse et une hémodilution sans conséquence clinique. Un temps de résection court, un faible niveau de pression d’irrigation, l’utilisation de l’anesthésie rachidienne nous semblent trés importants. Une surveillance clinique et biologique attentive pendant et après la résection transuréthrale de prostate sont nécessaires; en revanche, le choix du liquide d’irrigation ne semble pas l’élément essentiel.     

Intrathecal meperidine for elective Caesarean section: a comparison with lidocaine

The purpose of this study was to determine the efficacy of intrathecal meperidine in patients undergoing Caesarean section, and also to compare meperidine with heavy lidocaine. Fifty fall-term pregnant women, ASA physical status I or II, presenting for elective Caesarean section under spinal anaesthesia were randomly divided into two groups with 25 in each, to receive either intrathecal meperidine or lidocaine. All patients received premedication with oral ranitidine, 150 mg, the night before surgery, and again two hours before surgery. Patients in the meperidine group were also given metoclopramide iv 10 mg one hour before surgery. After iv 20 ml·kg^?1 Ringer’s lactate, patients were given either 5% meperidine 1 mg · kg^?1 or 5% heavy lidocaine 1.2 to 1.4 ml intrathecally. The sensory and motor blockades in all except two patients in each group who required sedation at the time of skin incision were adequate for surgery. None of the mothers suffered from any major side effects. The incidence of hypotension was higher in the lidocaine group than in meperidine group (P < 0.05). Pruritus and drowsiness were more common in meperidine group than in lidocaine group (P < 0.01). All the newborns in both groups cried immediately after birth and had an Apgar scope > 7. The mean duration of postoperative analgesia was six hours in the meperidine group and one hour in the lidocaine group (P < 0.01). Postoperative analgesia requirement was less in the meperidine than in the lidocaine group (P < 0.01). It is concluded that intrathecal 5% meperidine in a dose of 1 mg·kg^?1 is superior to 5% heavy lidocaine because of the prolonged postoperative analgesia. The commercial 5% solution of meperidine can be used, without addition, for this purpose.     

Effets de l’halothane sur la ventilation et les gaz du sang artériel chez le rat avec ou sans paralysie diaphragmatique

Certains patients atteints de paralysie diaphragmatique ou de dysfonctionnement diaphragmatique maintiennent leur ventilation par la mise en jeu d’autres muscles que le diaphragme. L’anesthésie, modifiant le fonctionnement de ces muscles, représente un risque potentiel chez ces patients. Afin d’évaluer ce risque, nous avons étudié les effets de l’halothane sur la ventilation et sur les gaz du sang artériel sur un modèle de paralysie diaphragmatique bilatérale, le rat phrénicectomisé. L’étude a été réalisée sur 43 rats. L’efficacité de la phrénicectomie a été contrôlée par l’observation directe, après laparotomie. La laparotomie n’entraine pas de modification des gaz du sang. Chez 23 rats, une laparotomie a été effectuée et une artère carotide a été cathétérisée. Chez 11 rats témoins, les nerfs phréniques ont été abordés, sans être sectionnés. Chez 12 rats, les phréniques ont été sectionnés. La ventilation a été mesurée par une technique pléthysmographique, chez les rats éveillés, avant et après l’opération, puis chez les mêmes rats anesthésiés avec 1,1%, d’halothane inspiré. Les gaz du sang ont été mesurés après l’opération chez les rats éveillés, puis anesthésiés. Chez les 23 rats opérés on observe, après l’opération, une diminution du poids et de la température centrale, plus importante chez les phrénicectomisés que chez les témoins. Chez les 11 rats témoins, après l’opération, la ventilation augmente, sans modification des gaz du sang. Chez ces rats, l’halothane provoque une diminution de la ventilation minute et de la PaO₂ et une augmentation de la PaCO₂. La phrénicectomie entraine chez les 12 rats, éveillés, une augmentation de la ventilation minute, une hypoxémie et une hypercapnie. Chez ces rats, l’halothane entraine le décès dans trois cas, une diminution de la ventilation minute et une hypercapnie et une hypoxémie importantes chez les neuf autres rats. Les modifications des gaz du sang sont plus importantes que chez les témoins anesthésiés. Chez le rat intact, l’halothane provoque des modifications des gaz du sang comparables à celles observées chez d’autres espèces et chez l’homme. La présente étude confirme les effets de l’halothane sur les muscles respiratoires autres que le diaphragme. Elle met en évidence le risque respiratoire majeur que l’anesthésie peut fair courir aux patients dont la ventilation est maintenue par d’autres muscles que le diaphragme.     

Upper airway obstruction during midazolam sedation: modification by nasal CPAP

We examined the depressant effect of midazolam on respiration in 21 healthy women undergoing lower abdominal surgery with spinal anaesthesia. Airway gas flow, airway pressure, and the sound of snoring were recorded together with arterial oxygen saturation (SpO₂. After spinal anaesthesia was established, subjects were deeply sedated with pentazocine 15 mg followed by incremental doses of midazolam 1 mg iv up to 0.1 mg · kg^?1. When SpO₂ decreased to < 90% or snoring and/or apnoea was observed, continuous positive airway pressure applied through the nose (nasal CPAP) was increased until the respiratory deterioration was reversed. While one patient remained free of respiratory events, the other 20 patients were successfully treated with nasal CPAP restoring normal SpO₂ (95.5 ± 1.7%) without snoring. Stepwise reduction of nasal CPAP determined the minimally effective CPAP to prevent snoring to be 5.1 ±2.1 cm H₂O. Further reduction of nasal CPAP induced snoring in 15 patients and obstructive apnoea in five patients with the latter accompanied by a severe reduction of SpO₂ (87.4 ± 6.1%). Patients with apnoea were older than those who snored (P < 0.05). We conclude that upper airway obstruction contributes considerably to decreases in SpO₂ during midazolam sedation for spinal anaesthesia.     

Propofol for pulsed dye laser treatments in paediatric outpatients

Pulsed dye laser is a new treatment for port-wine stains, congenital lesions in the cutaneous vascular plexus. We report our anaesthetic experience with paediatric outpatients treated in the dermatology clinic. From April to November 1993, 48 ASA 1 children were anaesthetised for a total of 105 consecutive laser treatments. The youngest was eight months old, the oldest was 12 yrs old and most of the sessions (43%) were done for children aged from two to four years. Each received acetaminophen (10 mg · kg^?1 po) before treatment. A propofol infusion was chosen for anaesthesia to achieve early discharge and to reduce the incidence of postoperative emesis. The infusion was adjusted to maintain blood pressure within 20% of baseline and to keep the child immobile. The dose was progressively reduced during the procedure from 400 μg · kg^?1 · min^?1 to 100 μg · kg^?1 · min^?1. Fentanyl (2 μg · kg^?1 iv) was added for analgesia. Respiration was spontaneous through a nasopharyngeal airway (air in oxygen 40%). Anaesthesia proceeded uneventfully in all cases and lasted for 15–30 min (63% of treatments), 30–45 min (28%) or 45–60 min (9%) according to the size of the lesion. The mean stay in the recovery room was 25.1 min and none of the patients experienced emesis. Our experience shows that general anaesthesia with propofol supplemented with fentanyl offers a rapid onset and awakening, a painless treatment and an immobile child. It is a safe solution to alleviate pain from repeated painful procedures even in small children under two years of age.     

Nasal ketamine for paediatric premedication

Ketamine in a dose of 6 mg · kg⁻¹ was nasally administered in 86 healthy children (ASA I and II), aged from two to five years undergoing elective general, urological or plastic surgery, 20 to 40 min before the scheduled surgery time. These children were compared with 62 others, also aged from two to five years, in whom promethazine and meperidine, 1 mg · kg⁻¹ of each, were injected im. Sedation was started as excellent in 48 and as adequate in 19 children in the ketamine group, compared with nine and 12 respectively in Group 2 (P < 0.05), while salivation was similar in both groups. We conclude that nasal ketamine is an alternative to im preanaesthetic sedation administration in children aged from two to five years. Vingt à quarante minutes avant la chirurgie, de la kétamine 6 mg · kg⁻¹ est administrée par voie nasale à 86 enfants en bonne santé (ASA I et II), agés de deux à cinq ans programmés pour une intervention urologique ou plastique non urgente sous anesthésie générale. On compare ces enfants à 62 autres enfants du même age, auxquels on a injecté par la voie i.m., soit de la mépéridine, soit de la prométhazine, à la dose de 1 mg · kg⁻¹. La sédation est jugée excellente pour 48 et adéquate pour 19 des enfants du groupe kétamine, comparativement à 9 et 12 des enfants du groupe 2 (P < 0,05), alors que la salivation est identique dans les deux groupes. Nous en concluons que la kétamine nasale est une alternative a la prémédication intramusculaire pour des enfants de deux à cinq ans.     

Sepsis reduces isoflurane MAC in a normotensive animal model of sepsis

Patients with sepsis often require anaesthesia for surgical procedures. Anaesthesia can be unpredictable and the most haemodynamically stable agents are used. No data are available for the minimum alveolar concentration (MAC) requirements in such patients or in animal models of sepsis. We have characterized the effect of sepsis on the MAC of isoflurane in a normotensive rodent model of sepsis. The minimum inhibitory concentration (MIC) of isoflurane to an identical stimulus was determined for rodents subjected to caecal ligation and perforation (CLP n = 8), or sham laparotomy (n = 7). The calculated MAC of isoflurane was reduced in the septic animals compared with the sham animals (MAC of isoflurane, CLP = 0.8% sham = 1.4% P < 0.003). No statistical differences were found in the haemodynamic variables measured in either group. Isoflurane leads to haemodynamic stability during anaesthesia in this animal model of sepsis. However, the MAC requirement for isoflurane is reduced by sepsis. En cas de sepsis, il faut souvent recourir à la chirurgie. Les répercussions anesthésiques sont imprévisibles et il faut utiliser des agents qui assurent la meilleure stabilité hémodynamique possible. Nous ne possédons pas de données sur la concentration alvéolaire minimale (MAC) requise chez le patients septique ou sur un modèle animal. Nous avons déterminé l’influence du sepsis sur le MAC de l’isoflurane sur un modèle de rongeur normotensif. La concentration inhibitrice minimale (MIC) de l’isoflurane à un stimulus identique a été déterminée chez des rongeurs soumis à une ligature et une perforation du caecum (CLP n = 8), ou une laparotomie factice (n = 7). Le MAC calculé de l’isoflurane diminuait chez les animaux septiques comparativement au groupe factice (MAC de l’isoflurane, CLP = 0,8%, factice = 1,4% P< 0,003). Nous n’avons pas trouvé de différence statistique pour les variables hémodynamiques entrer le deux groupes. L’isoflurane procure la stabilité hémodynamique sur ce modèle animal de sepsis. Cependant le MAC de l’isoflurane est abaissé.     

A comparison of the myocardial metabolic and haemodynamic changes produced by propofol-sufentanil and enflurane-sufentanil anaesthesia for patients having coronary artery bypass graft surgery

The purpose of this study was to compare propofol-sufentanil with enflurane-sufentanil anaesthesia for patients undergoing elective coronary artery bypass graft (CABG) surgery with respect to changes in (1) haemodynamic variables; (2) myocardial blood flow and metabolism; (3) serum cortisol, triglyceride, lipoprotein concentrations and liver function; and (4) recovery characteristics. Forty-seven patients with preserved ventricular function (ejection fraction greater than 40%, left ventricular end diastolic pressure less than or equal to 16 mmHg) were studied. Patients in Group A (n = 24) received sufentanil 0.2 microgram.kg-1 and propofol 1-2 mg.kg-1 for induction of anaesthesia which was maintained with a variable rate propofol (50-200 micrograms.kg-1.min-1) infusion and supplemental sufentanil (maximum total 5 micrograms.kg-1). Patients in Group B (n = 23) received sufentanil 5 micrograms.kg-1 for induction of anaesthesia which was maintained with enflurane and supplemental sufentanil (maximum total 7 micrograms.kg-1). Haemodynamic and myocardial metabolic profiles were determined at the awake-sedated, post-induction, post-intubation, first skin incision, post-sternotomy, and pre-cardiopulmonary bypass intervals. Induction of anaesthesia produced a larger reduction in systolic blood pressure in Group A (156 +/- 22 to 104 +/- 20 mmHg vs 152 +/- 26 to 124 +/- 24 mmHg; P less than 0.05). No statistical differences were detected at any other time or in any other variable including myocardial lactate production (n = 13 events in each group), time to tracheal extubation and time to discharge from the ICU. We concluded that, apart from hypotension on induction of anaesthesia, propofol-sufentanil anaesthesia produced anaesthetic conditions equivalent to enflurane-sufentanil anaesthesia for CABG surgery.     

Propofol anaesthesia reduces early post-operative emesis after paediatric strabismus surgery

Propofol anaesthesia may reduce postoperative emesis. The purpose of this study was to compare the incidence of emesis after propofol anaesthesia with and without nitrous oxide, compared with thiopentone and halothane anaesthesia, in hospital and up to 24 hr postoperatively, in outpatient paediatric patients after strabismus surgery. Seventy-five ASA class I or II, unpremedicated patients, aged 2–12 yr were randomly assigned to one of three groups: Thiopentone, 6.0 mg · kg^{? 1} iv induction followed by halothane and N₂O/O₂ for maintenance (T/H); propofol for induction, followed by propofol and oxygen for maintenance (P/O₂); and propofol for iv induction, followed by propofol infusion and N₂O/O₂ for maintenance (P/N₂O). All received vecuronium, controlled ventilation, and acetaminophen pr. Morphine was given as needed for postoperative analgesia. There were no differences in age, weight, number of eye muscles operated upon, duration of anaesthesia or surgery. The P/N₂O group (255 ± 80 μg· kg^{? 1}· min^{? 1}) received less propofol than the P/O₂ group (344 ± 60 μg · kg^{? 1}· min^{? 1}) (P ≤ 0.0001) and had shorter extubation (P < 0.001) and recovery (P < 0.01) times. Emesis in the hospital, in both the P/N₂O (4.0%) and P/O₂ group (4.0%) was less than in the T/H group (32%) (P < 0.01). Antiemetics were required in four patients in the T/H group (16.0%). Overall emesis after surgery was not different among the groups: T/H (48%), P/O₂ (28%) and P/N₂O (42%). The use of propofol anaesthesia with and without N₂O decreased only early emesis. This supports the concept of a short-acting, specific antiemetic effect of propofol.