The efficacy and safety of an adapted opioid-free anesthesia regimen versus conventional general anesthesia in gynecological surgery for low-resource settings: a randomized pilot study.

INTRODUCTION: There is scarce data on the safety and efficacy of opioid-free anesthesia (OFA), in resource-limited settings due to the non-availability of dexmedetomidine, the reference OFA agent. We aimed to demonstrate the feasibility, efficacy and safety of a practical OFA protocol not containing dexmedetomidine, adapted for low-resource environments in very painful surgeries like gynecological surgery. METHODS: We conducted a randomized pilot study on ASA I and II women undergoing elective gynecological surgery at a tertiary care hospital in Cameroon. Patients were matched in a ratio of 1:1 into an OFA and a conventional general anesthesia (CGA) group. The OFA protocol entailed the intravenous (IV) magnesium sulfate, lidocaine, ketamine, dexamethasone, propofol, and rocuronium, followed by isoflurane and a continuous infusion of a calibrated mixture of magnesium sulfate, ketamine and clonidine. The CGA protocol was IV dexamethasone, diazepam, fentanyl, propofol, and rocuronium, followed by isoflurane and reinjections of fentanyl propofol and a continuous infusion of normal saline as placebo. The primary endpoints were the success rate of OFA, isoflurane consumption and intraoperative anesthetic complications. The secondary endpoints were postoperative pain intensity, postoperative complications, patient satisfaction assessed using the QoR-40 questionnaire and the financial cost of anesthesia. RESULTS: We enrolled a total of 36 women undergoing gynecological surgery; 18 in the OFA group and 18 in the CGA group. The success rate of OFA was 100% with significant lesser consumption of isoflurane in the OFA group, no significant intraoperative complication and better intraoperative hemodynamic stability in the OFA group. Postoperatively, compared to the CGA group, the OFA group had statistically significantly less pain during the first 24 h, no morphine consumption for pain relief, had less hypoxemia during the first six hours, less paralytic ileus, less nausea and vomiting, no pruritus and better satisfaction. The mean financial cost of this adapted OFA protocol was statistically significant lesser than that of CGA. CONCLUSION: This OFA regimen without dexmedetomidine for a low-resource setting has a promising success rate with few perioperative complications including mild intraoperative hemodynamic changes, decrease postoperative complications, pain, and opioid consumption in patients undergoing elective gynecology surgery. TRIAL REGISTRATION: This study was registered at clinicaltrials.gov on 03/02/2021 under the registration number NCT04737473.

General versus regional anaesthesia for caesarean section indicated for acute foetal distress: a retrospective cohort study.

BACKGROUND: Acute foetal distress (AFD) is a life-threatening foetal condition complicating 2% of all pregnancies and accounting for 8.9% of caesarean sections (CS) especially in developing nations. Despite the severity of the problem, no evidence exists as to the safest anaesthetic technique for the mother and foetus couple undergoing CS for AFD. We aimed to compare general anaesthesia (GA) versus regional (spinal and epidural) anaesthesia in terms of their perioperative maternal and foetal outcomes. METHODS: We carried out a retrospective cohort study by reviewing the medical records of all women who underwent CS indicated for AFD between 2015 to 2018 at the Douala General Hospital, Cameroon. Medical records of neonates were also reviewed. We sought to investigate the association between GA, and regional anaesthesia administered during CS for AFD and foetal and maternal outcomes. The threshold of statistical significance was set at 0.05. RESULTS: We enrolled the medical records of 117 pregnant women who underwent CS indicated for AFD. Their mean age and mean gestational age were 30.5 ± 4.8 years and 40 weeks respectively. Eighty-three (70.9%), 29 (24.8%) and 05 (4.3%) pregnant women underwent CS under SA, GA and EA respectively. Neonates delivered by CS under GA were more likely to have a significantly low APGAR score at both the 1st (RR = 1.93, p = 0.014) and third-minute (RR = 2.52, p = 0.012) and to be resuscitated at birth (RR = 2.15, p = 0.015). Past CS, FHR pattern on CTG didn't affect these results in multivariate analysis. Adverse maternal outcomes are shown to be higher following SA when compared to GA. CONCLUSION: The study infers an association between CS performed for AFD under GA and foetal morbidity. This, however, failed to translate into a difference in perinatal mortality when comparing GA vs RA. This finding does not discount the role of GA, but we emphasize the need for specific precautions like adequate anticipation for neonatal resuscitation to reduce neonatal complications associated with CS performed for AFD under GA.

Malignant hyperthermia, a rare perioperative complication: case series and literature review.

Malignant hyperthermia is a rare complication of general anesthesia appearing as an acute and potentially lethal hypermetabolic state in people carrying a genetic anomaly expressed in skeletal muscles. Malignant hyperthermia has been scarcely described in sub-Saharan Africa. Herein, we present three cases of malignant hyperthermia occurring in the perioperative period in Cameroon. The authors wish to draw attention to the clinical presentation of this rare but potentially lethal emergency, for timely diagnosis, management and follow-up geared at preventing perioperative mortality.

Retraction Note: Severe Viperidae envenomation complicated by a state of shock, acute kidney injury, and gangrene presenting late at the emergency department: a case report.

The authors have retracted this case report [1] because the head of the snake shown in Figure 1 and described as being that of a viper (Echis occellatus) is identical to the head of a snake shown in Figure 1 of a different case report [2] where it was identified as being Naja melanoleuca, a member of the Elapidae family.

Anaesthesiologist-intensivist phycisians at the core of the management of critically ill COVID-19 patients in Africa: persistent challenges, some resolved dilemma and future perspective.

Unlike developed countries which have purely intensivists also called critical care physicians or intensive care physicians to manage critically ill patients like those with severe forms of COVID-19, the practice of critical care medicine in Africa is coined to anaesthesiology. Hence, anaesthesiologist-intensivist physicians are the medical specialists taking care of critically ill COVID-19 patients in Africa. Likewise, unlike intensive care units (ICUs) in high income countries, those in most African countries face the challenge of a lack of emergency drugs and resuscitation equipment, limited health infrastructure and understaffed and underfunded health care systems. The COVID-19 pandemic is an unprecedented one faced by intensivists in high-income countries and anaesthesiologist-intensivist phycisians in Africa. Infected patients with severe forms of the disease like those having grave COVID-19 complications like massive pulmonary embolism, severe cardiac arrhythmias, cardiogenic shock, septic shock, acute kidney injury or acute respiratory distress syndrome require ICU admission for better management. Both intensivists or anaesthesiologist-intensivist physicians have the peculiarity of securing the airways of critically COVID-19 patients and providing respiratory support with mechanical ventilation after laryngoscopy and endotracheal intubation when needed. In so doing, they can easily be infected from respiratory droplets or aerosols expired by the COVID-19 patients. Hence, in Africa, anaesthesiologist-intensivist phycisians have a higher risk of contracting COVID-19 compared to other health professionals. It's worth to mention that the COVID-19 pandemic struck African anaesthesiologist-intensivist phycisians and ICUs when there were neither prepared skillfully or lacked the required ICU capacity to meet the demands of thousands of severe COVID-19 African patients. These further weakened the already strained health systems in Africa. It required a lot of creativity, engineering skills and courage for these ill prepared African anaesthesiologist-intensivist physicians to provide care to these critically ill patients and improve their outcomes as the pandemic progressed. However, despites the numerous efforts made in African anaesthesiologist-Intensivist phycisians to care for critically ill COVID-19 patients, the pandemic is spreading at a rapid rate across Africa. There is an urgent need for African health authorities to anticipate on how to scale up the future high ICU capacity needs and limited ICU workforce, infrastructure and equipment to manage severe forms of COVID-19 in future. It cannot be overemphasized that these severe forms of COVID-19 are potentially fatal and are a major contributor to the death toll of the COVID-19 pandemic.

A comparative analysis of the diagnostic performances of four clinical probability models for acute pulmonary embolism in a sub-Saharan African population: a cross-sectional study.

BACKGROUND: The diagnosis of acute pulmonary embolism (PE) is one of the most challenging in emergency settings where prompt and accurate decisions need to be taken for life-saving purposes. Here, the assessment of the clinical probability of PE is a paramount step in its diagnosis. Although clinical probability models (CPM) for PE are routinely used in emergency departments (EDs) of low-resource settings, few studies have cited their diagnostic performances in sub-Saharan Africa (SSA). We aimed to comparatively assess the accuracy of four CPM in the diagnosis of acute PE in sub-Saharan Africans. METHODS: We carried out a cross-sectional study to compare the sensitivity, specificity, positive and negative predictive values and accuracy of four CPM namely; the Wells, simplified Wells, revised Geneva and the simplified revised Geneva (SRG) Scores to computed tomography pulmonary angiography (CTPA) in all adults patients with suspected PE admitted to the EDs of the Gynaeco-obstetric and Paediatric Hospital of Yaoundé and the Yaoundé Central Hospital in Cameroon between January 1, 2017 and April 30, 2018. RESULTS: In total, we enrolled 30 patients with clinical suspicion of acute PE. PE was confirmed on CTPA in 16 (53.3%) cases. Their mean age was 53.7 ± 15.5 years and 36.7% were males. All four scores had a diagnostic performance superior to 50% in all criteria assessed. The simplified Wells score had the highest sensitivity (62.5%) followed by the Wells score (56.3%). The SRG score had the highest specificity (71.4%). The score with highest PPV was the SRG score (66.7%) and that with the highest NPV was the Wells score (56.3%). Overall the models with the highest accuracies were the Wells and SRG scores (60% for each). CONCLUSION: All CPM had a suboptimal diagnostic performance, perhaps highlighting the need of a more optimal CPM for acute PE in SSA. However, the Wells and the SRG scores appeared to be most accurate than the other two scores in the ED. Hence, both or either of them may be used in first intention to predict PE and guide which ED patients should undergo further investigations in an emergency SSA setting.

Knowledge, attitudes, and practices of Cameroonian physicians with regards to acute pain management in the emergency department: a multicenter cross-sectional study.

INTRODUCTION: Pain is the most frequent presenting complaint in patients consulting or admitted to the emergency department (ED). Thus, its acute management is often done by physicians working in the ED. These clinicians are often general practitioners and not emergency medicine physicians in resource-poor settings. Hence, a mastery of pain management by these physicians may be important in relieving acute pain. We aimed to assess the knowledge, to determine the attitudes and practices of physicians in the management of pain in EDs of Cameroon. METHODS: We carried out a prospective cross-sectional study over 4 months in the year 2018. We enrolled all consenting physicians who were neither emergency medicine doctors nor anesthesiologists working at the EDs of five tertiary hospitals of Cameroon. Using a validated and pretested structured questionnaire, data on the knowledge, attitudes, and practices of acute pain management at the ED by these clinicians were studied. We used an externally validated score to assess the knowledge as either poor, insufficient, moderate or good. RESULTS: A total of 58 physicians were included; 18 interns or residents and 39 general practitioners. Their mean age was 28.6 ± 3 years and their average number of years of practice was 2.9 years. The level of knowledge was rated "poor" in 77.6% of physicians. Being a general practitioner was significantly associated with a poor level of knowledge (p = 0.02; OR = 5.1). We found a negative and significant correlation between knowledge and years of practice (p = 0.04; r2 = 0.06). More than three-quarter (82.8%) of participants used a pain scale to evaluate the severity of pain. The most used scale was the Visual Analog Scale (56.9%). The most frequently used analgesic was paracetamol (98.3%), although only 3.5% of physicians correctly knew its half-life, delay of onset of action and duration of action. CONCLUSION: These findings suggest that physicians in EDs of Cameroon have poor knowledge and suboptimal practices in pain management. General practice and a greater number of professional experience seemed to favour these attitudes. Overall, there is an urgent need for refresher courses in acute pain management for physicians working in these resource-limited EDs.

Severe Viperidae envenomation complicated by a state of shock, acute kidney injury, and gangrene presenting late at the emergency department: a case report.

BACKGROUND: Snake envenomation is an underestimated pathology in sub-Saharan Africa associated with severe emergencies, and even death in case of late presentation. We herein present a case of severe envenomation managed at the surgical emergency department of the Yaoundé Central Hospital. CASE PRESENTATION: We report a case of a 47-year-old female farmer with no relevant past history who sustained a snakebite by an Echis occellatus viper during an agricultural activity. Her initial management consisted in visiting a traditional healer who administered her some herbal remedies orally and applied a white balm on the affected limb. Due to progressive deterioration of her condition, she was rushed to our surgical department where she arrived 20 h after the snakebite incident. On admission she presented in a state of shock (suggestive of an anaphylactic shock), coagulopathy, renal impairment, and gangrene of the entire right upper limb. Emergency management consisted of fluid resuscitation, repeated boluses of adrenaline, a total of three vials of polyvalent anti-venom sera, promethazine, analgesics, corticosteroids, and administration of fresh frozen plasma. Within four hours of emergency department hospitalisation she developped signs of sepsis and persistent hypotension refractory to fluid resuscitation, suggestive of an associated septic shock. Management pursued with antiobiotherapy and administration of noradrenaline through an electric pump syringe to achieve a mean arterial blood pressure above 65 mmHg. The patient deceased at the 10th hour of hospitalisation in a state of circulatory collapse unresponsive to vasopressors, coagulopathy, renal failure, sepsis and gangrene of the right forearm. CONCLUSION: The authors highlight this unusual presentation but equally pinpoint how late presentation to the emergency department, harmful tradition practices, poverty and cultural beliefs can adversely affect the prognosis of snakebite in our setting.

Spontaneous haemorrhagic stroke complicating severe pre-eclampsia in pregnancy: a case report in a resource-limited setting in Cameroon.

BACKGROUND: Spontaneous intracerebral haemorrhage is a rare complication of preeclampsia during pregnancy associated with a high morbidity and mortality. Compared with the non-pregnant women stroke rates are relatively rare during pregnancy. CASE PRESENTATION: We report the case of a 32-year-old female Cameroonian gravida 4 para 3 who presented at 34 weeks of gestation with sudden onset of right sided hemiplegia associated with headache, blurred vision and a blood pressure of 182/126. Cerebral CT scan confirmed a left parietal spontaneous haemorrhage. Emergency caesarean delivery was done and the recovery uneventful. CONCLUSION: This case highlights the importance of good neurological examination in pregnant women presenting with neurological symptoms as well as the place of multidisciplinary management in severe life threatening conditions.

Posterior urethral valves: 10 years audit of epidemiologic, diagnostic and therapeutic aspects in Yaoundé gynaeco-obstetric and paediatric hospital.

BACKGROUND: The incidence of posterior urethral valve (PUV) is estimated at 1:5000-1:8000 males. It is the most common paediatric urologic urgency and the most common cause of male obstructive uropathy and chronic renal failure in children. The study aimed to describe the experience of Yaoundé gynaeco-obstetrics and paediatric hospital in the management of PUV. METHODS: Retrospectively, medical records were retrieved over a ten year period and all data recorded and analyzed for study objectives. Patients were called and evaluated for outcomes regarding morbidity and mortality. RESULTS: A total of 18 patients all males were managed over the ten year period, given prevalence of 13 cases/100,000 admissions and an admission rate of 2 per annum. The median age at presentation was 22 months and 13 (72.2%) participants presented late. Voiding urethrocystogram was done in all the participants where it showed dilated and elongated posterior urethral valves in 16 (88.9%) of the cases. Endoscopic valve ablation resulted in the relief of obstruction in all but 3 (16.7%) participants that had residual valves and 2 (11.2%) participants that had urethral stenosis. Type I valves were most common in 14 (78.0%) participants. The mean duration of follow up was 34.56 ± 21.47 months. Complications at final follow up were: 10 (55.6%) chronic renal failure, 2 (11.2%) end-stage renal failure. The case fatality rate was 5.6%. CONCLUSION: Many patients present late in our setting with already established complications. There is the need to counsel parents/guardians on the importance of long-term follow up after relief of obstruction.

Infantile hypertrophic pyloric stenosis: a 4-year experience from two tertiary care centres in Cameroon.

OBJECTIVE: This study aimed to describe the clinical characteristics of patients with infantile hypertrophic stenosis, management and its outcome in two tertiary care centres in Cameroon. RESULTS: A total of 21 patients were included from the two centres. The mean age at presentation was 5.2 ± 1.2 weeks, predominantly male with a male-to-female ratio of 4.25:1. The triad of vomiting, visible peristalsis and palpable mass was present in only 7 (33.3%) of the participants. The diagnosis was confirmed with ultrasounds in all participants. Ramstedt pyloromyotomy was done in all participants and in 9.5% of the participants it was complicated by intra-operative duodenal perforation whereas in the postoperative period the most common complications were vomiting (6, 28.6%), sepsis (2, 9.5%), and paralytic ileus (2, 9.5%). The mortality rate from the series is 9.5%. According to univariate logistic regression: severe dehydration [OR = 5.41, 95% CI = (3.11-6.97), p = 0.002], hypokalaemia [OR = 2.63, 95% CI = (1.02-5.91), p = 0.042] and surgical site infection [OR = 3.12, 95% CI (1.22-5.64), p = 0.023] were the main predictors of mortality whereas postoperative hospital length of stay > 5 days was significantly associated with surgical site infection [OR = 2.44, 95% CI = (1.12-6.44), p = 0.002] and postoperative nausea and vomiting [OR = 3.64, 95% CI = (1.18-6.64), p = 0.022].

Sublingual misoprostol and hyperpyrexia: case report with temperature curve.

BACKGROUND: Misoprostol has a wide range of applications in obstetrics and gynaecology. It is widely recommended by WHO, FIGO and ACOG for the treatment of postpartum haemorrhage due to it safety and cost-effectiveness. However, usage might be associated to hyperpyrexia and shivering. CASE PRESENTATION: We present a 30 year old Cameroonian female gravida 1 para 1 who had a vaginal delivery at 40 weeks of gestation complicated by primary postpartum haemorrhage (PPH). PPH was managed by sublingual misoprostol that induced shivering and hyperpyrexia managed successfully with paracetamol and cooling. CONCLUSIONS: The occurrence of fever and shivering should be kept in mind when administering misoprostol for PPH.

The challenge in the diagnosis and management of an advanced abdominal pregnancy in a resource-low setting: a case report.

BACKGROUND: Abdominal pregnancy is a rare form of ectopic pregnancy that is frequently left undiagnosed by inexperienced obstetricians and radiologists. It is associated with higher risk of maternal hemorrhage at any gestation and more at advanced gestation. CASE PRESENTATION: We present the case of a 22-year-old sub-Saharan African woman, gravida 3 para 0, who was diagnosed with advanced abdominal pregnancy of 25 weeks' gestation by a transvaginal ultrasound after the failure of two medical terminations of pregnancy in the first and second trimesters and a series of repeated obstetric ultrasounds showing intrauterine pregnancy. Laparotomy was done and her recovery was uneventful. CONCLUSIONS: The management of advanced abdominal pregnancy is more challenging as compared to earlier gestation so patients with failed medical termination of pregnancy should be critically analyzed for ectopic pregnancy as early as possible.

Etiologies de la mortalite maternelle a l'hopital gyneco-obstetrique et pediatrique de Yaounde: une serie de 58 deces

Objectifs: L'objectif de ce travail etait d'analyser les etiologies des deces maternels survenant dans un hopital de niveau tertiaire. Methodologie: Il s'agit d'une etude transversale avec collecte des donnees retrolective des deces maternels ayant eu lieu a l'Hopital Gyneco-Obstetrique et Pediatrique de Yaounde du 1er Janvier 2007 au 31 Decembre 2010. Tous les cas de deces maternels conformes a la definition de l'Organisation Mondiale de la Sante ont ete inclus. Les donnees ont ete analysees par les logiciels informatiques Epi info 3.5.1 et Excel 2007. Resultats: Cinquante-huit (58) deces maternels ont ete identifies pendant la periode de l'etude. Les principales causes de mortalite maternelle etaient : l'hypertension (22;4%); le VIH/SIDA (19;0%); les avortements septiques (17;2%); les hemorragies (13;8%); les cancers (10;3%) et la septicemie du post-partum (8;6%). Conclusion: L'hypertension; le VIH; et les avortements septiques sont les principales causes de mortalite dans cet hopital de niveau tertiaire. Les hemorragies ne sont responsables que d'une faible proportion des deces maternels. Nous recommandons la mise en place d'interventions visant a prevenir les deces maternels dus a l'hypertension en grossesse; a l'infection au VIH et aux avortements septiques. D'autre part; une politique hospitaliere basee sur la mise a disposition; sans frais exigibles en urgence; des paquets minimum pour les interventions obstetricales; de poches de sang et des equipes chirurgicales et anesthesiques; pourrait reduire efficacement la part des hemorragies dans la survenue des deces maternels en Afrique subsaharienne

Students' perspectives on research and assessment of a model template designed to guide beginners in research in a medical school in Cameroon.

BACKGROUND: Research activities for medical students and residents (trainees) are expected to serve as a foundation for the acquisition of basic research skills. Some medical schools therefore recommend research work as partial requirement for certification. However medical trainees have many difficulties concerning research, for which reason potential remedial strategies need to be constantly developed and tested. The views of medical trainees are assessed followed by their use and appraisal of a novel "self-help" tool designed for the purposes of this study with potential for improvement and a wider application. METHODS: This study was a cross-sectional survey of volunteering final-year medical students and residents of a medical school in Cameroon. RESULTS: This study surveyed the opinions of a total of 120 volunteers of which 82 (68%) were medical students. Three out of 82 (4%) medical students reported they had participated in research activities with a publication versus 10 out of 38 residents (26%). The reported difficulties in research for these trainees included referencing of material (84%), writing a research proposal (79%), searching for literature (73%) and knowledge of applicable statistical tests (72%) amongst others. All participants declared the "self-help" tool was simple to use, guided them to think and better understand their research focus. CONCLUSION: Medical trainees require much assistance on research and some "self-help" tools such as the template used in this study might be a useful adjunct to didactic lectures.

Gynaecological laparoscopic surgery: eight years experience in the Yaoundé Gynaeco-Obstetric and Paediatric Hospital, Cameroon.

This is a retrospective analysis of eight years of gynaecological laparoscopic surgery in a resource-limited setting. All gynaecological patients managed by laparoscopy at the Yaoundé Gynaeco-Obstetric and Paediatric Hospital from 1 January 2004 to 30 November 2011 were included. Amongst the 9194 gynaecological surgeries performed during the study period, 6.9% (633) were done by laparoscopy. Most of the women underwent an operative laparoscopy (568/592; 95.9%). The most common indication was infertility (415/592; 70.1%). Diagnostic laparoscopies were mostly indicated for chronic pelvic pain (18/24; 75%). The most common surgical finding was tubo-peritoneal adhesions (412/592; 69.6%). A total of 35 patients (35/592; 5.9%) had at least one complication. The mean duration of hospitalization was 3.4 ±1.8 days. The general uptake of gynaecological laparoscopic surgery is low in our setting. The laparoscopic complication rate of 5.9% is encouraging.

Syzyguim guineense Extracts Show Antioxidant Activities and Beneficial Activities on Oxidative Stress Induced by Ferric Chloride in the Liver Homogenate.

The aim of this study was to determine the in vitro antioxidant activity, free radical scavenging property and the beneficial effects of extracts of various parts of Syzygium guineense in reducing oxidative stress damage in the liver. The effects of extracts on free radicals were determined on radicals DPPH, ABTS, NO and OH followed by the antioxidant properties using Ferric Reducing Antioxidant Power assay (FRAP) and hosphomolybdenum (PPMB). The phytochemical screening of these extracts was performed by determination of the phenolic content. The oxidative damage inhibition in the liver was determined by measuring malondialdehyde (MDA) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase. Overall, the bark extract of the ethanol/water or methanol showed the highest radical scavenging activities against DPPH, ABTS and OH radicals compared to the other extracts. This extract also contained the highest phenolic content implying the potential contribution of phenolic compounds towards the antioxidant activities. However, the methanol extract of the root demonstrated the highest protective effects of SOD and CAT against ferric chloride while the hydro-ethanol extract of the leaves exhibited the highest inhibitory effects on lipid peroxidation. These findings suggest that antioxidant properties of S. guineense extracts could be attributed to phenolic compounds revealed by phytochemical studies. Thus, the present results indicate clearly that the extracts of S. guineense possess antioxidant properties and could serve as free radical inhibitors or scavengers, acting possibly as primary antioxidants. The antioxidant properties of the bark extract may thus sustain its various biological activities.

Le monitorage respiratoire per operatoire chez l'adulte

Le monitorage respiratoire est necessaire au cours de l'anesthesie car les agents anesthesiques depriment la ventilation. Il donc faut assurer une suppleance et la surveiller. Le monitorage n'exclut pas la surveillance clinique du patient par un personnel anesthesique present attentif en salle d'operation. Il est base sur l'oxymetrie de pouls; la capnographie; les parametres ventilatoires; les concentrations des gaz anesthesiques et les alarmes