Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: a registry study

Aims

Out-of-hospital cardiac arrest (OHCA) without return of spontaneous circulation (ROSC) despite conventional resuscitation is common and has poor outcomes. Adding extracorporeal membrane oxygenation (ECMO) to cardiopulmonary resuscitation (extracorporeal-CPR) is increasingly used in an attempt to improve outcomes.

Methods and results

We analysed a prospective registry of 13 191 OHCAs in the Paris region from May 2011 to January 2018. We compared survival at hospital discharge with and without extracorporeal-CPR and identified factors associated with survival in patients given extracorporeal-CPR. Survival was 8% in 525 patients given extracorporeal-CPR and 9% in 12 666 patients given conventional-CPR (P = 0.91). By adjusted multivariate analysis, extracorporeal-CPR was not associated with hospital survival [odds ratio (OR), 1.3; 95% confidence interval (95% CI), 0.8–2.1; P = 0.24]. By conditional logistic regression with matching on a propensity score (including age, sex, occurrence at home, bystander CPR, initial rhythm, collapse-to-CPR time, duration of resuscitation, and ROSC), similar results were found (OR, 0.8; 95% CI, 0.5–1.3; P = 0.41). In the extracorporeal-CPR group, factors associated with hospital survival were initial shockable rhythm (OR, 3.9; 95% CI, 1.5–10.3; P = 0.005), transient ROSC before ECMO (OR, 2.3; 95% CI, 1.1–4.7; P = 0.03), and prehospital ECMO implantation (OR, 2.9; 95% CI, 1.5–5.9; P = 0.002).

Conclusions

In a population-based registry, 4% of OHCAs were treated with extracorporeal-CPR, which was not associated with increased hospital survival. Early ECMO implantation may improve outcomes. The initial rhythm and ROSC may help select patients for extracorporeal-CPR.

Using virtual reality to control preoperative anxiety in ambulatory surgery patients: A pilot study in maxillofacial and plastic surgery

INTRODUCTION

Preoperative anxiety may lead to medical and surgical complications, behavioral problems and emotional distress. The most common means of prevention are based on using medication and, more recently, hypnosis. The aim of our study was to determine whether a virtual reality (VR) program presenting natural scenes could be part of a new therapy to reduce patients' preoperative anxiety.

MATERIALS AND METHODS

Our prospective pilot study consisted of a single-blind trial in skin cancer surgery at the Henri-Mondor teaching hospital in France. In the outpatient surgery department, 20 patients with a score of >11 on the Amsterdam preoperative anxiety and information scale (APAIS) were virtually immersed into a natural universe for 5minutes. Their stress levels were assessed before and after this experience by making use of a visual analog scale (VAS), by measuring salivary cortisol levels, and by determining physiological stress based on heart coherence scores.

RESULTS

The VAS score was significantly reduced after the simulation (P<0.009) as was the level of salivary cortisol (P<0.04). Heart coherence scores remained unchanged (P=0.056).

DISCUSSION

VR allows patients to be immersed in a relaxing, peaceful environment. It represents a non-invasive way to reduce preoperative stress levels with no side effects and no need for additional medical or paramedical staff. Our results indicate that VR may provide an effective complementary technique to manage stress in surgery patients. Randomized trials are necessary to determine precise methods and benefits.

[Necrotizing fasciitis: results of a survey on management practices in French-speaking intensive care units]

OBJECTIVES

Necrotizing fasciitis (NF) are rare and severe soft tissue infections associated with a high mortality rate. In order to assess the management of NF in French-speaking intensive care units (ICUs), we conducted a survey endorsed by the French Society of Anesthesia and Intensive Care (SFAR).

STUDY DESIGN

Online self-administered survey.

METHODS

A link to an online survey was sent by email to 4620 anesthesiologists and/or intensivists and was available online from January to February 2014.

RESULTS

One hundred and seventy-five physicians (3.8%) who worked in 135 ICUs filled out the online survey. Among respondents, 42% reported having managed up to two patients with NF during the previous year; 59% and 72% of respondents reported not having a surgical and a medical specialist consultant, respectively. A delayed access to the operating room (OR) of more than 6hours was reported in 31% of cases and access to the OR was reported not to be routinely considered as a priority in 13% of cases. Only 17% of respondents reported that time to transfer to the OR was never a cause for delayed surgery. The main causes for delayed surgery were: delayed diagnosis (45%), delayed validation of surgical intervention (37%), and difficulty of access to the OR (8%). Finally, 83% of respondents estimated that creating dedicated multidisciplinary teams for managing NFs could lead to improving outcomes.

CONCLUSION

This survey illustrates the heterogeneous management of NF in French-speaking ICUs and points out several logistical aspects that should be improved to reduce the time to the first surgical debridement.

Postoperative visual loss due to complicated mediastinal dissection and haemorrhagic shock treatment during cardiac surgery

We report the case of a patient who underwent third time revision of double heart valve replacement. Mediastinal dissection for right atrium cannulation was complicated by laceration of the superior vena cava; this required temporary rescue clamping of the vessel. The patient suffered complete visual loss related to bilateral retrobulbar haematoma. Acute elevation of superior vena cava pressure due to vascular clamping and administration of large amounts of fluid through the central venous jugular catheter could have caused the postoperative visual loss.

[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.

Influence of the cuff pressure on the swallowing reflex in tracheostomized intensive care unit patients

BACKGROUND

Because recovery of an efficient swallowing reflex is a determining factor for the recovery of airway protective reflexes, we have studied the influence of the tracheostomy tube cuff pressure (CP) on the swallowing reflex in tracheotomized patients.

METHODS

Twelve conscious adult intensive care unit (ICU) patients who had been weaned from mechanical ventilation were studied. Simultaneous EMG of the submental muscles with measurement of peak activity (EMGp) and amplitude of laryngeal acceleration (ALA) were performed during reflex swallows elicited by pharyngeal injection of distilled water boluses during end expiration. After cuff deflation, characteristics of the swallowing reflex (latency time: LaT, EMGp, and ALA) were measured at CPs of 5, 10, 15, 20, 25, 30, 40, 50, and 60 cm H(2)O.

RESULTS

LaT and CP were linearly related (P<0.01). CP was inversely correlated (P<0.01) to both ALA and EMGp.

CONCLUSIONS

We demonstrated that LaT, EMGp, and ALA of the swallowing reflex were influenced by tracheostomy tube CP. The swallowing reflex was progressively more difficult to elicit with increasing CP and when activated, the resulting motor swallowing activity and efficiency at elevating the larynx were depressed.

[Cricothyrotomy in emergency context: assessment of a cannot intubate cannot ventilate scenario]

OBJECTIVE

The aim of this study was to assess airway management by emergency physicians in case of a simulated situation where intubation and ventilation were both impossible.

STUDY DESIGN

Observational manikin study.

METHODS

A manikin (Airman®; Laerdal) allowing simulating difficult airway situations was used. The scenario assessed concerned a patient needing tracheal intubation for severe traumatic brain injury. The manikin was settled to make tracheal intubation under direct laryngoscopy impossible at the first attempt and to make facemask ventilation impossible after the second attempt. Manikin could initially be ventilated through the intubating laryngeal mask Airway (ILMA) but became impossible few seconds after its insertion. With impossible ventilation through the ILMA, arterial oxygen saturation decreased during 2 minutes before an hypoxic cardiac arrest occurred. Physicians could use classic laryngoscope with Macintosh blade, a Gum Elastic Bougie, an ILMA and a cricothyrotomy set. Adhesion to the national airway management algorithm was assessed. Time to cricothyroidotomy decision after ventilation through ILMA became impossible was measured.

RESULTS

Twenty-five emergency physicians were assessed. For 14 of them, national expert conference algorithm was perfectly followed. For ten physicians, cricothyroidotomy decision was taken after hypoxic cardiac arrest occurred.

CONCLUSION

Simulation with a manikin is useful to assess the adhesion rate to difficult intubation algorithms. Our study shows that the decision making process for cricothyrotomy is too often delayed as soon as ventilation became impossible and oxygenation compromized.

The learning process of the hydrolocalization technique performed during ultrasound-guided regional anesthesia

BACKGROUND

Because poor echogenicity of the needle remains a safety issue, we decided to analyze the learning process of the hydrolocalization technique (Hloc) performed to continuously identify needle-tip anatomical position during many ultrasound-guided regional anesthesia procedures.

METHODS

Ten senior anesthesiologists naïve to the Hloc agreed to participate in the study. They were requested to perform 40 out-of-plane (OOP) approach ultrasound-guided axillary blocks (AB) each using the Hloc. The Hloc, which is a needle-tip localization principle, was performed by means of repetitive injections of a small amount of a local anesthetic solution (0.5-1 ml) under an ultrasound beam. Details of the learning process and skill acquisition of the Hloc were derived from the following parameters: the duration of block placement, a measure of the perceived difficulty of needle-tip visualization, a measure of block placement difficulty, and the amount of local anesthetics solution required for the technique.

RESULTS

Four hundred ABs were performed. The success rate of an ultrasound-guided AB was 98%. The Hloc was successful in all patients. Skill acquisition over time of the Hloc was associated with a significant reduction of both the duration and the perceived difficulty of ABs placement. Apprenticeship data revealed that 20 blocks were required to successfully place AB within 5 min in most cases using the Hloc.

CONCLUSION

The Hloc performed during the OOP approach of ultrasound-guided regional anesthesia is a simple technique with a relatively short learning process feasible for efficient placement of ABs.

[High-risk airway management in pediatric prehospital emergency medicine]

We report the case of high-risk airway management performed in prehospital conditions in a 3-year-old boy suffering from a severe head and maxillofacial trauma. Tracheal intubation was decided because of a comatose status associated with an acute upper airway obstruction resulting in severe hypoxaemia. One minute after a rapid sequence induction, difficult laryngoscopy was encountered. Two tracheal intubation attempts failed. During maintained laryngoscopy, a pediatric angulated Eschmann-like stylet was blindly blocked into the trachea using a rotational maneuver. A tracheal tube was railroaded over the stylet while a hypoxic bradycardia installed. The young child was tracheostomized upon arrival in the hospital, and recovered without neurological complication. In the present case, neither facemask nor laryngeal mask ventilation would have been efficient because of oral cavity jaw and sub-mental pharyngeal open wounds. Since most paediatric emergency medicine physician are not familiar with infraglottic airway techniques, our observation questions the safety of rapid sequence induction in case of severe maxillofacial trauma and reinforces the value of pediatric Eschmann-like stylet. Minimal airway tools equipment for difficult paediatric airway management is discussed.

Sparing the larynx during gynecological laparoscopy: a randomized trial comparing the LMA Supreme and the ETT

BACKGROUND

We designed a prospective randomized single-blind study to compare efficiency and post-operative upper airway morbidity when the laryngeal mask airway (LMA) Supreme is used as an alternative to the endotracheal tube (ETT).

METHODS

One hundred and thirty-eight elective pelvic laparoscopic ASA I-II female patients were assigned to receive either the LMA Supreme or the ETT for airway management. Balanced anesthesia and ventilation techniques were standardized to control end-tidal CO(2) and BIS value in the range 4.5-5 kPa and 40-50, respectively, and to maintain adequate hemodynamic stability. A single surgeon blinded to the airway management technique performed all surgical procedures. The ventilation efficiency of each airway was evaluated. Anesthesia- and surgery-related times were calculated and anesthesia details were recorded. Post-operative pain and pharyngolaryngeal morbidity were measured in a blind fashion using a numerical rating scale (NRS) (0-100).

RESULTS

Surgery duration was similar in both groups. Airway management duration was shorter with the LMA Supreme. Post-operative pharyngolaryngeal morbidity incidence and all symptoms' intensity were significantly increased after ETT as compared with LMA Supreme anesthesia. At the end of the PACU stage, the incidence and mean NRS of post-operative hoarseness were reduced when LMA Supreme was used as an alternative to the ETT (16% vs. 47%; P<0.01 and 9 vs. 19, P<0.01, respectively).

CONCLUSION

We demonstrated that choosing an LMA Supreme was an efficient pharyngolaryngeal morbidity-sparing strategy. Moreover, we showed that the LMA Supreme and the ETT were equally effective airways for a routine gynecological laparoscopy procedure.

Effect of pre-incisional continuous regional block on early and late postoperative conditions in tibial osteotomy and total knee arthroplasty

Background:

Postoperative regional anesthesia hastens recovery and reduces the length of hospital stay of orthopedic surgical patients. This study was designed to assess the impact of pre-incisional continuous femoral block on postoperative conditions (POC) of tibial osteotomy and total knee arthroplasty patients.

Methods:

After insertion of a femoral catheter under peripheral nerve stimulation control, 111 patients scheduled for total knee arthroplasty or tibial osteotomy were randomized to receive either pre-incisionnal (treatment) or postoperative (control) continuous femoral block. Anesthesia and postoperative management was standardized. An assessor blinded to the randomization process recorded early and late postoperative conditions (POC) which included pain scores, opioid demands, length of stay in Postoperative care unit and patients’ satisfaction.

Results:

Eleven patients were excluded from the final analysis because of catheter disconnection or malfunction. Thus 100 patients (50 in each group) were analyzed for POC. Treatment failed to influence patients overall satisfaction but significantly improved early POC. Subgroup analysis demonstrated that late POC were significantly improved in tibial osteotomy as compared to total knee arthroplasty patients. No complication occurred during the study period.

Conclusion:

Continuous femoral nerve block before surgery significantly improved early postoperative conditions in both surgery while late postoperative conditions were improved only in tibial osteotomy.

Optimising tracheal intubation success rate using the Airtraq laryngoscope

In this study we have used a video-recording, retrospective analysis technique to evaluate the influence of the Airtraq laryngoscope manipulations and the resulting changes in position of the glottic opening and inter-arytenoids cleft, on the success rate of tracheal intubation. The video recordings of the internal views of 109 tracheal intubation attempts, in 50 anaesthetised patients were analysed. We demonstrated that successful tracheal intubation using the Airtraq laryngoscope require the glottic opening to be centred in the view, and positioning the inter-arytenoid cleft medially below the horizontal line in the centre of the view. We also demonstrated that repositioning of the Airtraq laryngoscope following a failed tracheal intubation attempt required the performance of a standard series of manoeuvres.

Post-tetanic count at adductor pollicis is a better indicator of early diaphragmatic recovery than train-of-four count at corrugator supercilii

BACKGROUND

Because the intensity of neuromuscular block at the diaphragm (DIA) is indirectly assessed, the electromyographic measurements of the DIA (DIA(EMG)) from surface electrodes were related to information provided by visual estimation of neuromuscular transmission at the adductor pollicis (AP) and the corrugator supercilii (CSC) during recovery from vecuronium block.

METHODS

Twelve adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agent, supramaximal stimulations were applied to phrenic, ulnar and facial nerves. During recovery from vecuronium 0.1 mg kg(-1) an independent observer blinded to DIA(EMG) counted visually detectable train-of-four (TOF) at CSC (TOF(CSC)) and post-tetanic AP (PTC(AP)) responses. Times to recovery of PTC(AP) = 1, <or=5, <10 and >10, and TOF(CSC) = 1-4 responses were related to DIA(EMG). Values are means (sd).

RESULTS

Reappearance of the first response to PTC(AP) occurred significantly (P < 0.05) earlier and for a lower recovery of DIA(EMG) than that of TOF(CSC) [24 (8) min vs 33 (9) min, and 10 (10)% vs 25 (8)%, respectively]. With PTC(AP) <or= 5 response, DIA(EMG) recovery was 21 (11)%. Recovery of TOF(CSC) = 1 and 2 coincided with DIA(EMG) recovery of 25 (8)% and 47 (9)%, respectively.

CONCLUSIONS

PTC(AP) may better reflect early recovery of vecuronium-induced DIA paralysis than TOF(CSC). The findings suggested that PTC(AP) <or= 5 warranted deep neuromuscular block of the DIA.

A comparison of two techniques for inserting the Airtraq™laryngoscope in morbidly obese patients

We postulated that video-controlled tracheal intubation with the Airtraq laryngoscope using the reverse manoeuvre instead of the standard technique of insertion could facilitate the airway management of morbidly obese patients. For the reverse manoeuvre the laryngoscope is inserted 180 degrees opposite to that recommended, and once in place rotated into the conventional pharyngeal position. Eighty (40 lean and 40 morbidly obese) ASA I-III adult patients were randomly allocated to four equal groups to compare the standard technique to the reverse manoeuvre for inserting the Airtraq laryngoscope. Video-controlled and clinical tracheal intubation characteristics were recorded. The reverse manoeuvre did not influence tracheal intubation characteristics in the group of lean patients. In the group of morbidly obese patients, the standard technique of insertion was not satisfactory in 20% of cases and the reverse manoeuvre facilitated, speeded and secured tracheal intubation.

Échec de traitement d'une pneumocystose par le cotrimoxazole: rôle de la co-infection par le cytomégalovirus?

Pneumocystis jiroveci pneumonia is a classic opportunist infection affecting AIDS patients. However it is less frequent since systematic prophylaxis and antiretroviral therapies. Treatment resistance is rare in France. We report the case of a severe Pneumocystis jiroveci pneumonia with treatment resistance to standard treatment and fatal outcome. The different causes of treatment resistance, notably the role of CMV co-infection, were reviewed and discussed.

TOF count at corrugator supercilii reflects abdominal muscles relaxation better than at adductor pollicis

BACKGROUND

A recovery profile from neuromuscular block similar to that of abdominal (AB) muscles, but different to that of the adductor pollicis (AP) muscle, has been demonstrated at the corrugator supercilii (CSC) muscle. We hypothesized that neuromuscular transmission (NMT) monitoring of CSC might provide useful information on AB relaxation compared with AP. We compared the visual estimation of NMT at CSC and AP with electromyographic measurements of AB during recovery from a vecuronium block.

METHODS

Ten adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agents, supramaximal stimulations were applied to three nerves: left 10th intercostal, ulnar, and facial. Electromyographic activity (EMG) of AB was measured (ABemg). After a bolus dose of vecuronium 0.1 mg kg-1, an independent observer blinded to the EMG measurements counted visually detectable train-of-four (TOF) responses at CSC and AP. Values of ABemg associated with 1 to 4 TOF responses at CSC and AP were compared. Values are means (sd).

RESULTS

Reappearance of the first and second TOF responses at CSC occurred significantly (P<0.05) earlier and at lower ABemg recovery than that of AP [35 (8) and 41 (9) min vs 51 (10) and 56 (12) min; and 17 (8) and 26 (9)% vs 56 (10) and 75 (11)%, respectively].

CONCLUSIONS

We demonstrated that the TOF response count at the CSC, compared with the AP, allowed a better quantification of the degree of AB muscle relaxation during recovery from vecuronium block.

Tracheal intubation of morbidly obese patients: LMA CTrach vs direct laryngoscopy

BACKGROUND

LMA CTrach (CT), a modified version of the intubating LMA Fastrach, allows continuous video-endoscopy of the tracheal intubation procedure. We tested the hypothesis that the CT is efficient for tracheal intubation of morbidly obese patients who are at risk of a difficult airway.

METHODS

After Ethics' Committee approval, 104 morbidly obese patients (BMI >35 kg m(-2)) scheduled for bariatric surgery were included in this prospective study. Patients were randomly assigned in two groups: tracheal intubation using direct laryngoscopy (DL) or the CT. Induction of anaesthesia was standardized using sufentanil, propofol and succinylcholine. Characteristics and consequences of airway management were evaluated.

RESULTS

Preoperative characteristics of patients and consequences of anaesthesia induction on physiological variables were similar in both groups. Difficulty in facemask ventilation was similar in both groups. Tracheal intubation was successfully carried out with DL and CT. Forty-nine per cent of the patients from the CT group required laryngeal mask manipulation (ventilation and view optimization) resulting in increased duration of tracheal intubation by 57 s as compared with DL. Oxygenation was of better quality in the patients managed with CT than with DL. Blind tracheal intubation was mandatory in eight (17%) patients of the DL group, while tracheal intubation was seen in all patients of the CT group.

CONCLUSION

We demonstrated that the CT was an efficient airway device for ventilation and tracheal intubation in case of a difficult airway in morbidly obese patients.

Carvedilol inhibits right ventricular hypertrophy induced by chronic hypobaric hypoxia

Right ventricular hypertrophy induced by chronic hypoxia is mainly due to a mechanical stress upon the ventricular wall secondary to pulmonary arterial hypertension. However, the hypoxic chronic activation of the sympathetic nervous system can contribute to the development of right ventricular hypertrophy either via myocardial adrenergic receptors and/or a vasoconstriction and remodeling of pulmonary arteries. To highlight the specific role of the sympathetic nervous system on hypoxia-induced right ventricular hypertrophy and particularly the efficiency of carvedilol, our study compared physiological, myocardial, and pulmonary arterial morphometric data in rats treated by alpha-(prazosin), or beta-(propranolol) or alphabeta-(carvedilol) antagonist and exposed to chronic hypobaric hypoxia (2 weeks at 380 mmHg barometric pressure). In chronic hypoxia, both systolic right ventricular pressure and Fulton's ratio (right/(left+septum) ventricular weight) were lower in rats treated by prazosin (-16.7 and -13.6%), propranolol (-28.6 and -12.7%) and carvedilol (-15.9 and -14.3%) respectively when compared to glucose (p<0.05). Surprisingly, prazosin was unable to reduce right ventricular hypertrophy induced by chronic hypoxia, whereas, left ventricular weight increased. Wall thickness index of pulmonary arteries increased in chronic hypoxia and was reduced by carvedilol. In conclusion, the hypoxia-induced activation of the adrenergic system participates in the development of right ventricular hypertrophy. Carvedilol is effective in reducing hypoxia-induced right ventricular hypertrophy, pulmonary arterial hypertension, and muscularization of pulmonary arteries.

Bloc plexique infraclaviculaire en monostimulation : l'injection au contact du faisceau postérieur permet de réduire le volume d'anesthésique local

OBJECTIVES

To assess the efficiency of a posterior secondary trunk single stimulation, low volume (30 ml 1.5% mepivacaine) infraclavicular brachial plexus block (ICB) technique.

STUDY DESIGN

Prospective study.

PATIENTS AND METHODS

One hundred consecutive patients scheduled for hand, forearm or elbow surgery were included. ICB was placed using a single stimulation technique. 30 ml 1.5% mepivacaine was injected when an evoked distal radial motor type response was elicited for 0.3-0.6 mA intensity current. Based upon both sensory and motor distribution ICB, characteristics and performance were assessed.

RESULTS

No patient required general anesthesia conversion. Success rate was 92%. 8 patients required a total amount of 10 complementary distal troncular blocks. No specific complication of ICB technique was accoutered. All patients completed full neurological recovery from ICB 24 hours after surgery.

CONCLUSION

30 ml mepivacaine 1.5% ICB is suitable for upper limb surgery.

[rFVIIa administration in patient with a left ventricular assistance patient]

We report the case of a left ventricular mechanical assistance (Incor Berlinheart) in a woman that experienced a postoperative non-surgical haemorrhagic complication following a reconstructive pedicled omentoplasty for implanted materials infection. After massive substitutive therapy failure at reducing blood loss and because of an hypovolaemic shock, high dosage (70 microg/kg twice) of recombinant activated factor VII (r-VIIa) was administrated resulting in spectacular cessation of bleeding and haemodynamic restoration. Continuous repeated clinical evaluation, cardiac echography and electronic monitoring of the axial pump device characteristic did not reveal any thromboembolic accident. This observation brings some indirect arguments for safe rFVIIa treatment in this type of pathology with a high thromboembolic risk.

Effect of metoclopramide on mivacurium-induced neuromuscular block

In order to investigate the effect of metoclopramide on the duration of action of mivacurium, 45 patients were randomized into three groups. Group M10 (n = 15) and M20 (n = 15) received 10 and 20 mg of metoclopramide i.v., respectively, and group S (n = 15) received saline 2 min before induction of anesthesia with fentanyl, thiopental and mivacurium. Plasma cholinesterase activity (pCHE) was measured before induction of anesthesia and 2 min after injection of metoclopramide and saline. Neuromuscular block was monitored by a force transducer using train of four nerve stimulation. Anesthesia was maintained with isoflurane and N2O. Time to recovery of a twitch height of 90% was significantly prolonged in group M10 and M20 (44 +/- 15 and 57 +/- 10 min) as compared to group S, 32 +/- 9 min, P < 0.05). A slight but significant decrease in pCHE was observed in group M20. Because of the risk of prolonged duration of action of mivacurium, neuromuscular blockade should always be monitored whenever metoclopramide is given before injection of mivacurium.

Differential sensitivity of abdominal muscles and the diaphragm to mivacurium: an electromyographic study

BACKGROUND

Respiratory muscles are considered to be more resistant to muscle relaxants as compared with peripheral muscles. However, the relative sensitivity of respiratory muscles participating to the pump function has not been compared. We used electromyography to compare pharmacodynamic parameters of the diaphragm and abdominal muscles after mivacurium.

METHODS

Forty adults undergoing elective surgery were randomly allocated in five dosing groups of mivacurium (50, 100, 150, 200, and 250 microg/kg). Patients anesthetized with propofol and fentanyl underwent intubation without relaxants. Anesthesia was maintained with nitrous oxide and propofol. The right phrenic nerve, the left 10th intercostal nerve, and the ulnar nerve were stimulated. Electromyography of the diaphragm and abdominal muscles was recorded from surface electrodes. Mechanomyography was used to measure adductor pollicis evoked contraction. After a 5-min stable recording period, patients received a single intravenous bolus (20 s) dose of mivacurium. By using log dose-probit effect regression analysis, dose-response curves were constructed. Effective doses and 95% confidence intervals were derived for the diaphragm and abdominal muscles and were compared.

RESULTS

The dose-response regression line of abdominal muscles differed from that of the diaphragm. Calculated ED50 and ED90 were higher for the diaphragm than for the abdominal muscles (104 [82-127] and 196 [177-213] microg/kg, and 67 [51-82] and 161 [143-181] microg/kg, respectively). The onset of block was faster and recovery of control responses were shorter at the diaphragm than at the abdominal muscles.

CONCLUSION

Diaphragm and abdominal muscles have differential sensitivity to mivacurium. The diaphragm is more resistant to mivacurium than abdominal muscles are.

Intracuff pressure and tracheal morbidity: influence of filling with saline during nitrous oxide anesthesia

BACKGROUND

Diffusion of nitrous oxide into the cuff of the endotracheal tube results in an increase in cuff pressure. Excessive endotracheal tube cuff pressure may impair tracheal mucosal perfusion and cause tracheal damage and sore throat. Filling the cuff of the endotracheal tube with saline instead of air prevents the increase in cuff pressure due to nitrous oxide diffusion. This method was used to test whether tracheal morbidity is related to excess in tracheal cuff pressure during balanced anesthesia.

METHODS

Fifty patients with American Society of Anesthesiologists physical status I or II were randomly allocated to two groups with endotracheal tube cuffs initially inflated to 20-30 cm H(2)O with either air (group A) or saline (group S). Anesthesia was maintained with isoflurane and nitrous oxide. At the time of extubation, a fiberoptic examination of the trachea was performed by an independent observer, and abnormalities of tracheal mucosa at the level of the cuff contact area were scored. Patients assessed their symptoms (sore throat, dysphagia, and hoarseness) at the time of discharge from the postanesthesia care unit and 24 h after extubation on a 101-point numerical rating scale.

RESULTS

Cuff pressure increased gradually during anesthesia in group A but remained stable in group S. The incidence of sore throat was greater in group A than in group S in the postanesthesia care unit (76 vs. 20%) and 24 h after extubation (42 vs. 12%; P < 0.05). Tracheal lesions at time of extubation were seen in all patients of group A and in eight patients (32%) of group S (P < 0.05).

CONCLUSION

Excess in endotracheal tube cuff pressure during balanced anesthesia due to nitrous oxide diffusion into this closed gas space causes sore throat that is related to tracheal mucosal erosion.