Strategy to Develop a Common Simulation Training Program: Illustration with Anesthesia and Intensive Care Residency in France

Phenomenon: The urgency of having fair and trustworthy competency-based assessment in medical training is growing. Simulation is increasingly recognized as a potent method for building and assessing applied competencies. The growing use of simulation and its application in summative assessment calls for comprehensive and rigorously designed programs. Defining the current baseline of what is available and feasible is a crucial first step. This paper uses anesthesia and intensive care (AIC) in France as a case study in how to document this baseline. Approach: An IRB-approved, online anonymous closed survey was submitted to AIC residency program directors and AIC simulation program directors in France from January to February 2021. The researcher-developed survey consisted of 65 questions across five sections: centers' characteristics, curricular characteristics, courses' characteristics, instructors' characteristics, and simulation perceptions and perspectives. Findings: The participation rate was 31/31 (100%) with 29 centers affiliated with a university hospital. All centers had AIC simulation activities. Resident training was structured in 94% of centers. Simulation uses were training (100%), research and development (61%), procedural or organizational testing (42%), and summative assessment (13%). Interprofessional full-scale simulation training existed in 90% of centers. Procedural training on simulators prior to clinical patients' care was performed "always" in 16%, "most often" in 45%, "sometimes" in 29% and "rarely" or "not" in 10% of centers. Simulated patients were used in 61% of centers. Main themes were identified for procedural skills, full-scale and simulated patient simulation training. Simulation activity was perceived as increasing in 68% of centers. Centers expressed a desire to participate in developing and using a national common AIC simulation program. Insights: Based on our findings in AIC, we demonstrated a baseline description of nationwide simulation activities. We now have a clearer perspective on a decentralized approach in which individual institutions or regional consortia conduct simulation for a discipline in a relatively homogeneous way, suggesting the feasibility for national guidelines. This approach provides useful clues for AIC and other disciplines to develop a comprehensive and meaningful program matching existing expectations and closing the identified gaps.

Differential Effect of Targeted Temperature Management Between 32 °C and 36 °C Following Cardiac Arrest According to Initial Severity of Illness: Insights From Two International Data Sets

BACKGROUND

Recent guidelines have emphasized actively avoiding fever to improve outcomes in patients who are comatose following resuscitation from cardiac arrest (ie, out-of-hospital cardiac arrest). However, whether targeted temperature management between 32 °C and 36 °C (TTM32-36) can improve neurologic outcome in some patients remains debated.

RESEARCH QUESTION

Is there an association between the use of TTM32-36 and outcome according to severity assessed at ICU admission using a previously derived risk score?

STUDY DESIGN AND METHODS

Data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (France) between May 2011 and December 2017 and in the Resuscitation Outcomes Consortium Continuous Chest Compressions (ROC-CCC) trial (United States and Canada) between June 2011 and May 2015 were used for this study. Severity at ICU admission was assessed through a modified version of the Cardiac Arrest Hospital Prognosis (mCAHP) score, divided into tertiles of severity. The study explored associations between TTM32-36 and favorable neurologic status at hospital discharge by using multiple logistic regression as well as in tertiles of severity for each data set.

RESULTS

A total of 2,723 patients were analyzed in the SDEC data set and 4,202 patients in the ROC-CCC data set. A favorable neurologic status at hospital discharge occurred in 728 (27%) patients in the French data set and in 1,239 (29%) patients in the North American data set. Among the French data set, TTM32-36 was independently associated with better neurologic outcome in the tertile of patients with low (adjusted OR, 1.63; 95% CI, 1.15-2.30; P = .006) and high (adjusted OR, 1.94; 95% CI, 1.06-3.54; P = .030) severity according to mCAHP at ICU admission. Similar results were observed in the North American data set (adjusted ORs of 1.36 [95% CI, 1.05-1.75; P = .020] and 2.42 [95% CI, 1.38-4.24; P = .002], respectively). No association was observed between TTM32-36 and outcome in the moderate groups of the two data sets.

INTERPRETATION

TTM32-36 was significantly associated with a better outcome in patients with low and high severity at ICU admission assessed according to the mCAHP score. Further studies are needed to evaluate individualized temperature control following out-of-hospital cardiac arrest.

Peri-operative management of an adult with POLG-related mitochondrial disease

POLG-related mitochondrial disease is a rare mitochondrial disorder that is potentially associated with anaesthetic complications such as propofol-related infusion syndrome. A 19-year-old man with mitochondrial DNA deletions and POLG-related disorders presented for an elective robotic Heller-Dor myotomy for the treatment of oesophageal pseudo-achalasia associated with severe gastro-oesophageal reflux. The fasting period was minimised to reduce the risk of metabolic stress. The anaesthetic technique included a rapid sequence induction with propofol and rocuronium, a remifentanil and sevoflurane-based general anaesthesia with multimodal monitoring and peri-operative lactate-free intravenous fluids with added dextrose. The patient did not experience propofol-related infusion syndrome but did have delayed tracheal extubation due to residual neuromuscular blockade requiring a second dose of sugammadex. This report demonstrates the safety of single-use, low-dose propofol in this patient group. Patients with POLG-related mitochondrial disease may be at risk of prolonged neuromuscular blockade, and appropriate dosing of neuromuscular blocking agents with monitoring of neuromuscular blockade is strongly encouraged.

Rapid identification of bacteria from respiratory samples of patients hospitalized in intensive care units, with FilmArray Pneumonia Panel Plus

OBJECTIVES

This study aimed to evaluate the performance of FilmArray Pneumonia Panel Plus (FA-PP) for the detection of typical bacterial pathogens in respiratory samples from patients hospitalized in intensive care units (ICUs).

METHODS

FA-PP was implemented for clinical use in the microbiology laboratory in March 2020. A retrospective analysis on a consecutive cohort of adult patients hospitalized in ICUs between March 2020 and May 2020 was undertaken. The respiratory samples included sputum, blind bronchoalveolar lavage (BBAL) and protected specimen brush (PSB). Conventional culture and FA-PP were performed in parallel.

RESULTS

In total, 147 samples from 92 patients were analysed; 88% had coronavirus disease 2019 (COVID-19). At least one pathogen was detected in 46% (68/147) of samples by FA-PP and 39% (57/147) of samples by culture. The overall percentage agreement between FA-PP and culture results was 98% (93-100%). Bacteria with semi-quantitative FA-PP results ≥10⁵ copies/mL for PSB samples, ≥10⁶ copies/mL for BBAL samples and ≥10⁷ copies/mL for sputum samples reached clinically significant thresholds for growth in 90%, 100% and 91% of cultures, respectively. FA-PP detected resistance markers, including mecA/C, bla_CTX-M and bla_VIM. The median turnaround time was significantly shorter for FA-PP than for culture.

CONCLUSIONS

FA-PP may constitute a faster approach to the diagnosis of bacterial pneumonia in patients hospitalized in ICUs.

Phenotype and genotype characteristics of 58 patients showing a prolonged effect of succinylcholine: A four-year experience

INTRODUCTION

This study sought to describe the phenotype and genotype characteristics of patients referred to our laboratory to undergo further assessment due to a suspicion of a prolonged effect of suxamethonium attributed to BChE deficiency.

METHODS

All patients referred to our laboratory from January 2016 to December 2019 due to the suspicion of a prolonged effect of suxamethonium were included in this study. The determination of BChE activity and genotyping using complete nucleotide sequencing of the entire complementary DNA-coding region with flanking intron-exon boundaries were completed.

RESULTS

During this four-year period, 58 patients were referred to our laboratory for the investigation of prolonged neuromuscular block due to BChE deficiency. Among them, 52 showed a BChE deficiency related to BCHE gene mutations. The most commonly detected genotype was compound homozygous atypical variant (p.Asp98Gly)/homozygous Kalow variant (p.Ala569Thr) (p.[Asp98Gly;Ala567Thr];[p.Asp98Gly;Ala567Thr]). Further, we recorded four new BCHE variants, which seem to be associated with prolonged post suxamethonium apnoea: p.(Trp205Cys), p.(Leu222His), p.(Glu469Gln), and p.(Lys276Ter).

CONCLUSION

During a four-year period, among the 58 patients referred to our laboratory, we have found four new BCHE variants, which seem to be associated with prolonged post suxamethonium apnoea (p.(Trp205Cys), p.(Leu22His), p.(Glu469Gln), and p.(Lys276Ter)).

A national healthcare response to intensive care bed requirements during the COVID-19 outbreak in France

Background

Whereas 5415 Intensive Care Unit (ICU) beds were initially available, 7148 COVID-19 patients were hospitalised in the ICU at the peak of the outbreak. The present study reports how the French Health Care system created temporary ICU beds to avoid being overwhelmed.

Methods

All French ICUs were contacted for answering a questionnaire focusing on the available beds and health care providers before and during the outbreak.

Results

Among 336 institutions with ICUs before the outbreak, 315 (94%) participated, covering 5054/5531 (91%) ICU beds. During the outbreak, 4806 new ICU beds (+95% increase) were created from Acute Care Unit (ACU, 2283), Post Anaesthetic Care Unit and Operating Theatre (PACU & OT, 1522), other units (374) or real build-up of new ICU beds (627), respectively. At the peak of the outbreak, 9860, 1982 and 3089 ICU, ACU and PACU beds were made available.

Before the outbreak, 3548 physicians (2224 critical care anaesthesiologists, 898 intensivists and 275 from other specialties, 151 paediatrics), 1785 residents, 11,023 nurses and 6763 nursing auxiliaries worked in established ICUs. During the outbreak, 2524 physicians, 715 residents, 7722 nurses and 3043 nursing auxiliaries supplemented the usual staff in all ICUs. A total number of 3212 new ventilators were added to the 5997 initially available in ICU.

Conclusion

During the COVID-19 outbreak, the French Health Care system created 4806 ICU beds (+95% increase from baseline), essentially by transforming beds from ACUs and PACUs. Collaboration between intensivists, critical care anaesthesiologists, emergency physicians as well as the mobilisation of nursing staff were primordial in this context.

Performance of a multiplex polymerase chain reaction panel for identifying bacterial pathogens causing pneumonia in critically ill patients with COVID-19

The FilmArray® Pneumonia Plus (FA-PP) panel can provide rapid identifications and semiquantitative results for many pathogens. We performed a prospective single-center study in 43 critically ill patients with coronavirus disease 2019 (COVID-19) in which we performed 96 FA-PP tests and cultures of blind bronchoalveolar lavage (BBAL). FA-PP detected 1 or more pathogens in 32% (31/96 of samples), whereas culture methods detected at least 1 pathogen in 35% (34/96 of samples). The most prevalent bacteria detected were Pseudomonas aeruginosa (n = 14) and Staphylococcus aureus (n = 11) on both FA-PP and culture. The FA-PP results from BBAL in critically ill patients with COVID-19 were consistent with bacterial culture findings for bacteria present in the FA-PP panel, showing sensitivity, specificity, and positive and negative predictive value of 95%, 99%, 82%, and 100%, respectively. Median turnaround time for FA-PP was 5.5 h, which was significantly shorter than for standard culture (26 h) and antimicrobial susceptibility testing results (57 h).

Guidelines on muscle relaxants and reversal in anaesthesia

OBJECTIVES

To provide an update to the 1999 French guidelines on "Muscle relaxants and reversal in anaesthesia", a consensus committee of sixteen experts was convened. A formal policy of declaration and monitoring of conflicts of interest (COI) was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were required to follow the rules of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE®) system to assess the quality of the evidence on which the recommendations were based. The potential drawbacks of making strong recommendations based on low-quality evidence were stressed. Few of the recommendations remained ungraded.

METHODS

The panel focused on eight questions: (1) In the absence of difficult mask ventilation criteria, is it necessary to check the possibility of ventilation via a facemask before muscle relaxant injection? Is it necessary to use muscle relaxants to facilitate facemask ventilation? (2) Is the use of muscle relaxants necessary to facilitate tracheal intubation? (3) Is the use of muscle relaxants necessary to facilitate the insertion of a supraglottic device and management of related complications? (4) Is it necessary to monitor neuromuscular blockade for airway management? (5) Is the use of muscle relaxants necessary to facilitate interventional procedures, and if so, which procedures? (6) Is intraoperative monitoring of neuromuscular blockade necessary? (7) What are the strategies for preventing and treating residual neuromuscular blockade? (8) What are the indications and precautions for use of both muscle relaxants and reversal agents in special populations (e.g. electroconvulsive therapy, obese patients, children, neuromuscular diseases, renal/hepatic failure, elderly patients)? All questions were formulated using the Population, Intervention, Comparison and Outcome (PICO) model for clinical questions and evidence profiles were generated. The results of the literature analysis and the recommendations were then assessed using the GRADE® system.

RESULTS

The summaries prepared by the SFAR Guideline panel resulted in thirty-one recommendations on muscle relaxants and reversal agents in anaesthesia. Of these recommendations, eleven have a high level of evidence (GRADE 1±) while twenty have a low level of evidence (GRADE 2±). No recommendations could be provided using the GRADE® system for five of the questions, and for two of these questions expert opinions were given. After two rounds of discussion and an amendment, a strong agreement was reached for all the recommendations.

CONCLUSION

Substantial agreement exists among experts regarding many strong recommendations for the improvement of practice concerning the use of muscle relaxants and reversal agents during anaesthesia. In particular, the French Society of Anaesthesia and Intensive Care (SFAR) recommends the use of a device to monitor neuromuscular blockade throughout anaesthesia.

Impact of renin-angiotensin system inhibitors continuation versus discontinuation on outcome after major surgery: protocol of a multicenter randomized, controlled trial (STOP-or-NOT trial)

BACKGROUND

Chronic treatment of hypertension or heart failure very often includes an angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) as renin-angiotensin system inhibitors (RASi) treatments. To stop or not to stop these medications before major surgery remains an unresolved issue. The lack of evidence leads to conflicting guidelines with respect to RASi management before major surgery. The purpose of this study is to evaluate the impact of a strategy of RASi continuation or discontinuation on perioperative complications in patients undergoing major non-cardiac surgery.

METHODS

This is a multicenter, open-labeled randomized controlled trial in > 30 French centers. In the experimental group, RASi will be continued while the treatment will be stopped 48 h before the surgery in the control arm. The primary endpoint is a composite endpoint of major complications after surgery. An endpoint adjudication committee will review clinical data and adjudicate efficacy endpoints while blinded to the assigned study drug group. Main analysis will be by intention-to-treat comparing the composite outcome measure at 28 days in the two groups. A total of 2222 patients are planned to detect an absolute complications difference of 5%.

DISCUSSION

The results of the trial should provide robust evidence to anesthesiologists and surgeons regarding management of RASi before major non-cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03374449 . Registered on 11 December 2017.

Heart rate variability and cardiac baroreflex inhibition-derived index predicts pain perception in burn patients

BACKGROUND

Dressing changes induce acute pain in burn patients. This pain is difficult to predict and may be therefore undertreated. Two different non-invasive electrophysiological indices from heart rate variability and baroreflex inhibition-derived indices, analgesia/nociception index (ANI) and cardiovascular depth of analgesia (CARDEAN), have been proposed to predict and better assess adequacy of anti-nociception. The aim of this study was to evaluate these techniques as early pain alert tools in conscious burnt patients during dressing changes' procedures.

METHODS

Twenty adult burnt patients undergoing scheduled wound treatment procedures were included in this prospective observational study. Pain intensity was assessed using a 0-10 numerical rating scale (NRS) and was compared with both ANI and CARDEAN, during the procedures. Non parametric rank sum test and linear discriminant analysis were used for evaluating potential differences of measured variables between periods with different pain intensities. Receiver-operating characteristic (ROC) curves were built to assess their performance to detect pain within following 15s.

RESULTS

The sensitivity and specificity of ANI to detect pain were 67% and 70% and those of CARDEAN were 77% and 80%, with area under the curve (AUC) values of 0.75 and 0.83, respectively. Their combination increased AUC to 0.87.

CONCLUSIONS

Both ANI and CARDEAN indices during wound treatment procedures seem to discriminate periods with and without pain within 15s, serving as a potential complementary tool for early optimized pain control.

Clinical, biological, and microbiological pattern associated with ventriculostomy-related infection: a retrospective longitudinal study

BACKGROUND

Our aim was to describe the pattern of ventriculostomy-related infection (VRI) development using a dynamic approach.

STUDY DESIGN

Retrospective longitudinal study.

METHODS

We analyzed the files of 449 neurosurgical patients who underwent placement of external ventricular drain (EVD). During the study period, CSF sampling was performed on a daily base setting. VRI was defined as a positive CSF culture resulting in antibiotic treatment. For VRI patients, we arbitrary defined day 0 (D0) as the day antibiotic treatment was started. In these patients, we compared dynamic changes in clinical and biological parameters at four pre-determined time points: (D-4, D-3, D-2, D-1) with those of D0. For all CSF-positive cultures, we compared CSF biochemical markers' evolution pattern between VRI patients and the others, considered as a control cohort.

RESULTS

Thirty-two suffered from VRI. Peripheral white blood cell count did not differ between D-4-D0. Median body temperature, CSF cell count, median Glasgow Coma Scale, CSF protein, and glucose concentrations were significantly different between D-4, D-3, D-2, and D0. At D0, 100 % of CSF samples yielded organisms in culture. The physician caring for the patient decided to treat VRI based upon positive CSF culture in only 28 % (9/32) of cases. In the control cohort, CSF markers' profile trends to normalize, while it worsens in the VRI patients.

CONCLUSIONS

We showed that clinical symptoms and biological abnormalities of VRI evolved over time. Our data suggest that VRI decision to treat relies upon a bundle of evidence, including dynamic changes in CSF laboratory exams combined with microbiological analysis.

From the Skin to the Brain: Pathophysiology of Colonization and Infection of External Ventricular Drain, a Prospective Observational Study

Ventriculostomy-related infection (VRI) is a serious complication of external ventricular drain (EVD) but its natural history is poorly studied. We prospectively tracked the bacteria pathways from skin towards ventricles to identify the infectious process resulting in ventriculostomy-related colonization (VRC), and VRI. We systematically sampled cerebrospinal fluid (CSF) on a daily basis and collected swabs from both the skin and stopcock every 3.0 days for microbiological analysis including in 101 neurosurgical patient. Risk factors for positive event defined as either VRC or VRI were recorded and related to our microbiological findings. A total of 1261 CSF samples, 473 skin swabs, and 450 stopcock swabs were collected. Skin site was more frequently colonized than stopcock (70 (60%) vs 34 (29%), p = 0.023), and earlier (14 ±1.4 vs 24 ±1.5 days, p<0.0001). Sixty-one (52%) and 32 (27%) skin and stopcock sites were colonized with commensal bacteria, 1 (1%) and 1 (1%) with pathogens, 8 (7%) and 1 (1%) with combined pathogens and commensal bacteria, respectively. Sixteen positive events were diagnosed; a cutaneous origin was identified in 69% of cases. The presence of a pathogen at skin site (6/16 vs 4/85, OR: 11.8, [2.5–56.8], p = 0.002) and CSF leakage (7/16 vs 6/85, OR 10 [2.4–41.2], p = 0.001)) were the two independent significant risk factors statistically linked to positive events occurrence. Our results suggest that VRC and VRI mainly results from an extra-luminal progression of pathogens initially colonizing the skin site where CSF leaks.

Anaesthesia and intensive care management of face transplantation

The face-grafting techniques are innovative and highly complex, requiring well-defined organization of all the teams involved. Subsequent to the first report in France in 2005, there have been 17 facial allograft transplantations performed worldwide. We describe anaesthesia and postoperative management, and the problems encountered, during the course of seven facial composite tissue grafts performed between 2007 and 2011 in our hospital. The reasons for transplantation were ballistic trauma in four patients, extensive neurofibromatosis in two patients, and severe burns in one patient. Anaesthesia for this long procedure involves advanced planning for airway management, vascular access, technique of anaesthesia, and fluid management. Preparation and grafting phases were highly haemorrhagic (>one blood volume), requiring massive transfusion. Median (range) volumes given for packed red cell (PRC) and fresh-frozen plasma (FFP) were 64.2 ml kg(-1) (35.5-227.5) and 46.2 ml kg(-1) (6.3-173.7), respectively. Blood loss quantification was difficult because of diffuse bleeding to the drapes. The management of patients with neurofibromatosis or burns involving the whole face was more difficult and haemorrhagic than the patients with lower face transplantation. Average surgical duration was 19.1 h (15-28 h). Postoperative severe graft oedema was present in most patients. Most patients encountered complications in ICU, such as renal insufficiency, acute respiratory distress syndrome, and jugular thrombosis. Opportunistic bacterial infections were a feature during the postoperative period in these highly immunosuppressed patients.

[French survey on perioperative nutrition in cirrhotic adult patients waiting for liver transplantation]

OBJECTIVE

The European Society for Clinical Nutrition and Metabolism (EPSEN) guidelines on nutrition for liver disease patients has been recently updated. The aim of our study was to evaluate perioperative nutrition in cirrhotic patients waiting for liver transplantation (LT).

STUDY DESIGN

Prospective electronic survey. A standardized questionnaire was sent to the anaesthesiologist of the 18 French adult LT centers. The questionnaire had closed-ended questions to evaluate nutritional practices in cirrhotic patients waiting for a LT.

RESULTS

The response rate was 100%. Nutritional status of the cirrhotic patients waiting for LT was assessed by anaesthesiologists (12 centres) and/or hepatologists (11 centres) and more rarely by nutrition physician, dietetics or liver surgeons. Body mass index (13 centres), weight loss (10 centres), albuminemia (10 centres) were the most frequent items used to assess the nutritional status. Before LT, preoperative oral intakes were administered in undernourished patients in only 55% of the cases. Postoperatively, nutritional support was administered between day 1 and 3 after LT.

CONCLUSION

Perioperative nutritional practices in cirrhotic patients waiting for LT are heterogeneous between centers, especially about nutrition assessment. Most of the centres did not follow the actual guidelines.

[Anesthesia in the elderly]

A growing number of old or very old patients benefits from a surgical procedure. Age is an independent risk factor of postoperative mortality and postoperative complications including cognitive dysfunction. The choice of anesthetic technique does not significantly modify this risk. Preventive strategies and preoperative procedures can be implemented. A multidisciplinary management involving all care providers around the patient is essential to reduce the risk of dependence after surgery which is higher in this population. Early postoperative rehabilitation is recommended in the elderly to improve the prognosis.

Recurarization after sugammadex reversal in an obese patient

PURPOSE

We report a case that involved immediate postoperative respiratory failure necessitating tracheal intubation, which was possibly related to recurarization after sugammadex reversal.

CLINICAL FINDINGS

A 54-yr-old woman weighing 115-kg was scheduled for laparoscopic repair of abdominal dehiscence under general anesthesia. Muscle relaxation was induced and maintained with rocuronium (170 mg iv total dose). At the end of the 170-min procedure, two twitches were visualized after supramaximal train-of-four (TOF) stimulation at the adductor pollicis muscle, and the patient's central core temperature was 35.6°C. Sugammadex 200 mg iv (1.74 mg·kg(-1)) was administered. With the patient fully awake, a TOF ratio 0.9 was obtained five minutes later. The tracheal tube was then removed, and the patient was transferred to the postanesthesia care unit. Ten minutes later, the patient presented respiratory failure necessitating tracheal intubation and sedation with propofol. One TOF response only was visualized at the adductor pollicis muscle. Another dose of sugammadex 200 mg iv was administered. Forty-five minutes later, the patient was fully awake and her trachea was extubated after repeated measures of the TOF ratio (≥ 0.9) at the adductor pollicis muscle. The patient fully recovered without sequelae, further complication, or prolonged hospital stay.

CONCLUSION

Shortly after tracheal extubation, an obese patient experienced respiratory failure necessitating tracheal intubation and an additional dose of sugammadex. This occurred despite initial reversal of neuromuscular blockade with an appropriate dose of sugammadex 2 mg·kg(-1) iv given at two responses to TOF stimulation.

The electrophysiological effects of racemic ketamine and etomidate in an in vitro model of "border zone" between normal and ischemic/reperfused guinea pig myocardium

BACKGROUND

Etomidate and ketamine are used during induction of anesthesia in high-risk patients. However, their effects on action potential (AP) variables and ischemia/reperfusion-induced arrhythmias and conduction blocks are unknown.

METHODS

Guinea pig right ventricular muscle strips were mounted in a 5-mL double chamber bath with the strips separated into two zones by an impermeable latex membrane. One-half (normal zone) was exposed to normal perfusate while the other half (altered zone) was exposed to hypoxia, hyperkalemia, acidosis, and lack of glucose. AP variables were recorded continuously in the normal and altered zones. Spontaneous arrhythmias and conduction blocks were noted. Etomidate (10(-7), 10(-6), and 10(-5) M) and ketamine (10(-6), 10(-5), and 10(-4) M) were superfused into the bath throughout the experiment and the electrophysiologic effects compared with the control group.

RESULTS

We found that under control conditions, etomidate and ketamine did not modify resting membrane potential, maximal upstroke velocity, AP amplitude, or AP duration at 90% of repolarization (APD90). Ketamine (10(-4) M), but not weaker concentrations and none of the concentration of etomidate, reversed the ischemia-induced shortening of APD90 and APD dispersion. Etomidate and ketamine did not modify the occurrence of conduction block during simulated ischemia. In contrast, ketamine (25% at 10(-6) M, 13% at 10(-5) M, and 13% at 10(-4) M vs 90% in the control group, P < 0.05) but not etomidate (38% at 10(-7) M, 63% at 10(-6) M, and 63% at 10(-5) M vs 90% in the control group, NS) decreased the incidence of reperfusion-induced spontaneous arrhythmias.

CONCLUSIONS

In guinea pig myocardium, our data suggest that ketamine, in clinically relevant concentrations, decreases ischemia-induced AP shortening and spontaneous reperfusion-induced ventricular arrhythmias. Further study is required to precisely determine the effect of etomidate on reperfusion-induced arrhythmias.

Hypothermie après rachianesthésie : rôle de la morphine ?

Spinal anaesthesia is the gold standard for elective caesarean section. This technique presents several adverse effects. We report a severe case of hypothermia (33.3 degrees C) after spinal administration of bupivacaine (10 mg) and morphine (100 microg) for elective caesarean section. After excluding other causes of hypothermia, this one could be explained by both the own effects of local anaesthesia (i.e. peripheral vasodilatation) and by the central effect of intrathecal morphine. Because hypothermia is not predictable after spinal injection of morphine both monitoring of central temperature and active warming of the patients could be proposed. Naloxone has been proposed in a case of hypothermia related to spinal injection of morphine.

Role of Hyaluronidase in Diplopia after Peribulbar Anesthesia for Cataract Surgery

OBJECTIVE

To determine the protective action of hyaluronidase on peribulbar anesthesia-related diplopia in patients undergoing cataract surgery.

DESIGN

Single-center observational case series.

PARTICIPANTS

All patients undergoing elective phacoemulsification and intraocular lens implantation under peribulbar anesthesia between February 2001 and January 2003.

METHODS

We compared the incidence of postoperative diplopia between 2 periods--February 2001 to January 2002 (P1) and February 2002 to January 2003 (P2)--which differed by the presence (P1) or absence (P2) of hyaluronidase in the anesthetic solution.

MAIN OUTCOME MEASURES

All patients were examined on the first and fifth postoperative days during both periods. When diplopia was diagnosed, we recorded the characteristics of the patient, peribulbar anesthesia, and diplopia (orthoptic examination, and magnetic resonance imaging in some cases).

RESULTS

Seven thousand two hundred five patients were studied. During P1, 3582 patients received peribulbar anesthesia, and no cases of diplopia occurred. During P2, 3623 patients received peribulbar anesthesia, and 27 cases of diplopia occurred (incidence, 0.75%; P = 0.0002 vs. P1). Diplopia involved the inferior rectus (40%) and the external rectus (37%) muscles. Diplopia was persistent in 54% of the cases.

CONCLUSIONS

Peribulbar anesthesia-related diplopia was significantly more frequent when hyaluronidase was not added to the anesthetic solution.

Sevoflurane effects on retrobulbar arteries blood flow in children

BACKGROUND

Measure of blood flow velocity in retrobulbar vessels is performed to determine the severity of ophthalmic pathologies as glaucoma. In children, this measure is usually performed under general anaesthesia. Sevoflurane is known to not modify cerebral blow flow velocities. However, its effect on retrobulbar circulation is not known. This study was designed to evaluate the effect of sevoflurane on retrobulbar circulation flow velocity in children undergoing examination for ocular disorders under general anaesthesia.

METHODS

Thirteen mechanically ventilated children (Fi(O2))=1) were included. Blood flow velocities of central retinal artery, ophthalmic artery, and middle cerebral artery were measured by Doppler ultrasound during 1 and 2 age-adjusted minimal alveolar concentration (MAC) sevoflurane anaesthesia. Intra-ocular pressure and non-invasive haemodynamic parameters were also measured. End-tidal carbon dioxide tension was controlled during all the study period.

RESULTS

Mean arterial pressure decreased from 1 to 2 age-adjusted MAC sevoflurane (58 [12] vs 54 [12] mm Hg, P=0.01). In the ophthalmic artery, end diastolic velocity (EDV) decreased significantly at 2 MAC (1 MAC: 4.4 [4] cm s(-1) vs 2 MAC: 1.4 [2.4] cm s(-1); P=0.04) and resistivity index (RI) increased significantly (1 MAC: 0.83 [0.11] vs 2 MAC: 0.93 [0.09]; P=0.007). Systolic velocity, EDV, and RI remained constant in the central retinal artery and in the middle cerebral artery.

CONCLUSION

High alveolar concentration of sevoflurane decreased blood flow velocity in the ophthalmic artery, but not in the central retinal and the middle cerebral arteries in children ventilated in hyperoxic condition. This effect was related to a decrease in mean arterial pressure. This vessel-dependent effect may be explained by the different autoregulatory mechanisms of these arteries. In the present hyperoxic conditions, the vascular effect of sevoflurane may have been limited in the central retinal artery and not in the ophthalmic artery.

Cuff compliance of pediatric and adult cuffed tracheal tubes: an experimental study

BACKGROUND

Tracheal mucosal damage related to tracheal intubation has been widely described in pediatric and adult patients. High volume-low pressure cuffs (HVLPC) are being advertised as safe to avoid this particularly unpleasant complication. Compliances of these supposed pediatric and adult HVLPC are not mentioned by manufacturers and still remain unknown.

METHODS

The compliance of HVLPC was measured in vitro and defined as the straight portion of the pressure-volume curve. Cuff pressure was measured after incremental 0.1 ml filling volumes of air for sizes 3.0-8.0 of internal diameter of Rüsch and Mallinckrodt tracheal tubes. Compliances were assessed in air and in a rigid tube. The filling volume to achieve a 25-mmHg intracuff pressure was also measured.

RESULTS

In air, each 0.1 ml step almost linearly increased cuff pressure by 1 mmHg (size 8.0) to 9 mmHg (size 3). In air, the volume needed to maintain a cuff pressure < 25 mmHg was small for sizes 3-5.5 (0.35-2 ml). The 25 mmHg inflated cuff volume and compliance were decreased within a rigid tube, especially for adult sizes. In a rigid tube simulating a trachea, the compliances of almost every Rüsch tracheal tube were statistically higher than those of the Mallinckrodt.

CONCLUSION

We conclude that the tested tracheal tube cuffs have low compliance and cannot be defined as high volume-low pressure.

Early exploration of diplopia with magnetic resonance imaging after peribulbar anaesthesia

We report the cases of five patients who have experienced postoperative diplopia after cataract surgery under peribulbar anaesthesia and in whom orbital Magnetic Resonance Imaging was performed immediately after the diagnosis. In four patients, the imaging study showed a T2 hyper-intensity signal and swelling of one extraocular muscle that was interpreted as oedema. Therefore, these cases were most probably a result of an accidental i.m. injection of local anaesthetics. In the other patient, the imaging study revealed no abnormality.

Residual paralysis in the PACU after a single intubating dose of nondepolarizing muscle relaxant with an intermediate duration of action

BACKGROUND

Residual neuromuscular blockade remains a problem even after short surgical procedures. The train-of-four (TOF) ratio at the adductor pollicis required to avoid residual paralysis is now considered to be at least 0.9. The incidence of residual paralysis using this new threshold is not known, especially after a single intubating dose of intermediate-duration nondepolarizing relaxant. Therefore, the aim of the study was to determine the incidence of residual paralysis in the postanesthesia care unit after a single intubating dose of twice the ED(95) of a nondepolarizing muscle relaxant with an intermediate duration of action.

METHODS

Five hundred twenty-six patients were enrolled. They received a single dose of vecuronium, rocuronium, or atracurium to facilitate tracheal intubation and received no more relaxant thereafter. Neuromuscular blockade was not reversed at the end of the procedure. On arrival in the postanesthesia care unit, the TOF ratio was measured at the adductor pollicis, using acceleromyography. Head lift, tongue depressor test, and manual assessment of TOF and DBS fade were also performed. The time delay between the injection of muscle relaxant and quantitative measurement of neuromuscular blockade was calculated from computerized anesthetic records.

RESULTS

The TOF ratios less than 0.7 and 0.9 were observed in 16% and 45% of the patients, respectively. Two hundred thirty-nine patients were tested 2 h or more after the administration of the muscle relaxant. Ten percent of these patients had a TOF ratio less than 0.7, and 37% had a TOF ratio less than 0.9. Clinical tests (head lift and tongue depressor) and manual assessment of fade showed a poor sensitivity (11-14%) to detect residual blockade (TOF < 0.9).

CONCLUSION

After a single dose of intermediate-duration muscle relaxant and no reversal, residual paralysis is common, even more than 2 h after the administration of muscle relaxant. Quantitative measurement of neuromuscular transmission is the only recommended method to diagnose residual block.

Intrathecal + PCA morphine improves analgesia during the first 24 hr after major abdominal surgery compared to PCA alone

PURPOSE

To compare, over a 48-hr follow-up period, the analgesia and side-effects of patient controlled iv analgesia (PCA) with morphine alone vs combined intrathecal and PCA morphine (IT+PCA) in patients undergoing major abdominal surgery.

METHODS

Sixty adult patients undergoing abdominal surgery for cancer were randomly allocated to receive preoperative IT (0.3 or 0.4 mg) plus postoperative PCA morphine or postoperative PCA morphine alone. Postoperative analgesia was tested at rest and while coughing on a visual analogue pain scale and morphine consumption was recorded. Patients' satisfaction, arterial oxygen saturation, respiratory rate, episodes of nausea, vomiting and pruritus were also noted.

RESULTS

Analgesia at rest and while coughing was significantly better in the IT+PCA morphine group (rest: P = 0.01; coughing: P = 0.005) on the first postoperative day only. IT+PCA morphine constantly provided adequate analgesia during this period. Morphine consumption was lower in the IT+PCA morphine group during this period also (IT+PCA: 9 (17) vs PCA: 40 (26); mg of morphine, mean (SD), P = 0.0001). No difference was found in pain relief and morphine consumption between the groups on the second postoperative day. Nausea and vomiting were more frequent with IT+PCA morphine on the first postoperative day. No respiratory depression occurred in either group. Satisfaction was high in both groups.

CONCLUSIONS

IT+PCA morphine improves patient comfort constantly during the first postoperative day after major abdominal surgery. However, after the first postoperative day, IT+PCA morphine provides no additional benefit.

[Neuromuscular blockade monitoring at the corrugator supercilii and ocular myasthenia gravis]

A 67-year-old patient suffering from an ocular myasthenia gravis was scheduled for an elective ENT surgery. General anaesthesia was induced intravenously. Neuromuscular responses after train-of-four stimulation were normal at both the adductor pollicis (T(4)/T(1) = 1) and the corrugator supercilii (4 visual responses). Then cisatracurium (0,15 mg kg(-1)) was administered to allow tracheal intubation. The laryngoscopy attempted 45 s after cisatracurium injection (no response at the supercilii, T(1)/T(0) = 1 at the adductor pollicis) was unsuccessful because of closing and moving vocal cords. The second attempt was successful 4 min after cisatracurium injection (no response at the corrugator supercilii, T(1)/T(0) = 0.05 at the adductor pollicis). Residual neuromuscular blockade was antagonized at the end of surgery (1 h long) allowing an uneventful extubation. We concluded that monitoring neuromuscular blockade at the corrugator supercilii to assess the intubating conditions is not recommended in a case of ocular myasthenia gravis.