Difficult intubation and extubation in adult anaesthesia.

OBJECTIVE: To provide an update to French guidelines about "Difficult intubation and extubation in adult anaesthesia 2006". DESIGN: A consensus committee of 13 experts was convened. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Few recommendations were ungraded. METHODS: The panel focused on 6 questions: 1) Why must oxygen desaturation be avoided during intubation and what preoxygenation and oxygenation techniques should be used to prevent it? 2) Should videolaryngoscopes be used instead of standard laryngoscopy with or without a long stylet to achieve a better success rate of intubation after the first attempt during anticipated difficult intubation off fiberoptic intubation? 3) Should TCI or target controlled inhalation anaesthesia (TCIA) be used instead of bolus sedation for airway control in the event of suspected or proven difficulty in a patient spontaneously breathing? 4) What mode of anaesthesia should be performed in patients with difficult intubation criteria and potentially difficult mask ventilation? 5) In surgical patients, what criteria predict difficulties encountered during postoperative tracheal extubation? 6) Should decision trees and algorithms be employed to direct decision-making for the management of difficult intubation, whether foreseen or not? (based on the information from the preceding five issues). Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. The analysis of the literature and the recommendations were then conducted according to the GRADE® methodology. RESULTS: The SFAR Guideline panel provided 13 statements on difficult intubation and extubation in adult anaesthesia. After two rounds of discussion and various amendments, a strong agreement was reached for 99% of recommendations. Of these recommendations, five have a high level of evidence (Grade 1±), 8 have a low level of evidence (Grade 2±). No recommendation was provided for one question. CONCLUSIONS: Substantial agreement exists among experts regarding many strong recommendations for the best care of patients with difficult intubation and extubation in adult anaesthesia.

Rescue transtracheal jet ventilation during difficult intubation in patients with upper airway cancer.

INTRODUCTION: The failure rates of intubation and/or mask ventilation are higher in patients with neck or upper airway disease. To ensure oxygenation, rescue trans-tracheal jet ventilation (RTTJV) may be used. In this critical situation, a high rate of complications has been reported. The aim of this study was to report RTTJV performed by a jet ventilator with an end-expiratory pressure control in an experienced institution. PATIENTS AND METHODS: From a computerised database of 63,905 anaesthesia cases, the anaesthetic reports of patients who underwent emergency RTTJV during intubation were studied retrospectively. The following information were analysed: anaesthetic procedures, data from the monitoring: lowest SpO2, duration of SpO2<90%, and complications. Success of emergency RTTJV was defined when SpO2 was>90% under jet ventilation. RESULTS: RTTJV was used in 31 patients, of whom 26 had upper airway cancer, (pre-treatment, n=9, post-treatment, n=17). Difficult intubation was anticipated in 15 out of 31 cases including six fiber-optic-aided intubations under spontaneous ventilation. RTTJV was effective in all cases with quick restoration of oxygenation (SpO2>90%). During jet ventilation, final airway control was performed either by oral intubation (n=25) or tracheotomy (n=1) in a short delay (mean: 8.1±1.7min). Subcutaneous emphysema was observed in one case without pneumothorax. CONCLUSION: RTTJV with end-expiratory pressure control allowed oxygenation during difficult intubation, with a low rate of complications.

Preoxygenation and general anesthesia: a review.

Because intubation can potentially become a lengthy procedure, the risk of arterial oxygen (O2) desaturation during intubation must be considered. Preoxygenation should be routine, as oxygen reserves are not always sufficient to cover the duration of intubation. Three minutes of spontaneous breathing at FiO2=1 allows denitrogenation with FAO2 close to 95% in patients with normal lung function. Tolerable apnea time, defined as the delay until the SpO2 reaches 90%, can be extended up to almost 10 minutes after 3 minutes of classic preoxygenation. Eight deep breaths within 60 seconds allow a comparable increase in O2 reserves. For effectiveness, the equipment must be adapted and tightly fitted. Inadequate preoxygenation (FeO2 <90% after three minutes tidal volume breathing) is frequently observed. Predictive risk factors for inadequate pre-oxygenation share overlap with criteria predictive of difficult mask ventilation. In cases of respiratory failure, oxygenation can be improved by positive end expiration pressure or by pressure support. In morbidly obese patients, preoxygenation is enhanced in a seated position (25°) and by use of positive pressure ventilation. O2 can also be administered during the intubation procedure; techniques include pharyngeal O2, special oxygen mask, or even pressure support ventilation for patients with spontaneous ventilation or positive pressure ventilation to the facial mask for apneic patients. Clinicians (especially anesthesiologists trained in ENT and traumatology) must be prepared to handle life-threatening emergency situations by alternate methods including trans-tracheal ventilation. The availability of equipment and training are two essential components of adequate preparation.

[About laryngeal mask: is the lowest price material the better cost-efficacy choice?]. / Comparaison de quatre masques laryngés à usage unique pour la chirurgie carcinologique du sein: une approche médico-économique.

OBJECTIVE: The main goal of this study was to achieve a medico-economic comparison between four disposable laryngeal masks (LM) (LMA-Unique™, Ambu AuraOnce™, I-Gel™ and LMA-Suprême™). STUDY DESIGN: A prospective, randomized, monocentre study. MATERIAL AND METHODS: In a center, using routinely LMA-Unique masks, scheduled breast surgery patients were allocated into four groups according to the LM model. After the induction, the modalities of use were collected, as well as the intraoperative events that required additional anesthetic equipment. The real cost of each model was calculated (cost of the mask+extra cost related to complications). Using the LMA-Unique as a reference, we performed a cost-efficacy analysis. We realized a cost-efficiency analysis putting in parallel the impact on the cost and the incidence of the events. RESULTS: A total of 178 patients were included. According to the cost-efficacy analysis, the dominant model was the Ambu AuraOnce™ (Δreal cost: -34.2%, Δevents: -30.6%). The LMA-Unique™ was dominated because of a high morbidity rate. The I-Gel™ and LMA-Suprême™ models were more efficient but more expensive (Δreal cost: +16% and +22.5% respectively). To compensate for additional costs, it would be necessary to apply a price reduction of at least 50%. CONCLUSIONS: Despite their better efficiency and safety, the latest generation laryngeal masks are still expensive in spite of a low rate of complication. These results do not take into account very rare and severe complications not met in this study in the limited size; then the economic and medical impact can influence the choice beyond the simple analysis cost-efficiency.

What are the main "machine dysfunctions" to know?

The incidents related to the medical devices are common during anesthesia and in intensive care unit. These incidents are rarely the cause of complications because monitoring detects them early; alternative scenarios allow bearing these problems. Although the incidence of these complications has much declined, these incidents are serious adverse events and at the origin of life-threatening complications. Improper use of medical devices is the main factor that promotes the onset of these complications. To maintain a high level of security, it is necessary to use and control procedures according to the manufacturer recommendations. This is part of a strategy involving users, biomedical engineers and manufacturers. Several actions are effective in preventing the occurrence of these incidents: the control before use, the continuation of the performance of the equipment, use based on the recommendations of the experts and manufacturers and appropriate training. This strategy is best applied by a clinical expert who has extensive technical knowledge. This expert is a key player for users learning and allows establishing and maintaining rules of use in collaboration with medical staff and biomedical engineers and manufacturers.

[Recurrent syncope in head and neck cancer: a case report]. / Tumeur ORL responsable de syncopes à répétition: cas clinique.

The repeated syncopes in case of head and neck cancer are a complication rarely described in the literature. They occur when the tumor invade the carotid sinus or the afferent fibers of the glossopharyngeal nerve. We report the case of a 62-year-old man presented episodes of syncope synchronous of a recurrent hypopharyngeal tumor scheduled for chemotherapy and gastrostomy. A computerized tomography showed a voluminous tumor expanded to the carotid and parapharyngeal spaces. After treatment by isporenaline chlorhydrate in intensive care unit, a pacemaker was implanted to prevent syncopes and allowed the beginning of the chemotherapy.

Airway fire during tracheostomy.

INTRODUCTION: Twenty-five cases of airway fire during tracheostomy have been reported in the literature. The authors describe a case observed in their centre 3 years ago, discuss the causes and preventive management and propose guidelines for prevention of this complication. CASE REPORT: A 66-year-old woman was intubated and ventilated with 100% oxygen during general anaesthesia for tracheostomy. On opening the trachea by monopolar diathermy, the oxygen present in the endotracheal tube caught fire, inducing combustion of the tube spreading to the lower airways. This airway fire was responsible for severe acute respiratory failure and the formation of multiple laryngotracheal stenoses. DISCUSSION: Combustion of the endotracheal tube due to ignition of anaesthetic gases induced by the heat generated by diathermy is responsible for airway fire. These various phenomena are discussed. Prevention is based on safety measures and coordination of surgical and anaesthetic teams.

[Impact of the decrease of nitrous oxide use on the consumption of halogenated agents]. / Impact de la diminution d'utilisation du protoxyde d'azote sur la consommation d'agents halogénés.

OBJECTIVE: Nitrous oxide (N2O) toxicity and its impact on pollution lead to restrict its use. A decrease of N2O consumption should increase the hypnotic inhaled consumption. This monocentric study estimated consumptions and costs of halogenated agents (HA) and N2O over 5 years when the N2O consumption was reduced. STUDY DESIGN: Retrospective from a computerized database. PATIENTS: Between 2006 and 2010, 34,097 procedures were studied after two meetings exposing the risks of the N2O. METHODS: At the end of anesthesia, consumptions of hypnotic agents (millilitres transmitted by the injectors and the blender) were archived in the database. The annual consumption of agents was obtained by adding the individual consumptions, then divided by the annual number of cases. The costs were given by the hospital pharmacy from invoices. RESULTS: N2O consumption per anesthesia constantly decreased during the study, from 75.1L by act to 22.7L. The sum of the annual consumptions of N2O and air did not change suggesting that total fresh gas flow remained stable. Between 2006 and 2010, the sevoflurane consumption by act increased by 25%, from 16.5 to 20.6mL, and desflurane consumption by 37%, from 46.1 to 63.1mL by patient. The costs of the administration of hypnotic agents remained stable. CONCLUSION: N2O consumption decrease had an impact on the consumption of HA. The cost reduction of the N2O was counterbalanced by the increase of halogenated vapor cost. The profit of the ecological impact of the reduction in N2O use could be quantified.

[Assessment of the French surgical checklist: the experience of 17 French cancer centres]. / Évaluation et applicabilité de la check-list HAS au quotidien: expérience des centres de lutte contre le cancer.

INTRODUCTION: The use of WHO checklist has been associated to a decrease of complication incidence and mortality. This control is mandatory since January the 1st 2010. Evaluation of the quality of documentation is important and includes filling rate, which is a reflexion of participant adhesion and analysis of the circumstances where the team answers "no" during the control. METHODS: This study concerned 17 among 20 French cancer centres. Percentage of documented checklist, exhaustivity of the answers in each checklist and "no" answers have been compared during two periods: January 2010 and October 2010. RESULTS: Rate of filled document is satisfactory and stable during the two periods (95.5% versus 95.8%). Exhaustivity was slightly better during the second period (64 and 68%, P=0,039). Nevertheless, variability between centres was large; one centre improved and four centres worsened their scores. Rate of "no" answers was low and increased during the second period (1.5% in January 1.9% in October P<0.001). They mainly concerned antibiotic administration and at a lesser degree bleeding risk, the name of the procedure, equipment problem to be addressed and postoperative management. DISCUSSION: There is a large discrepancy between centres and for a given centre in reporting quality. Significant progress should be expected using target improvement. This approach implies multiple critical analysis of checklist content in each hospital and in multicentre enquiries.

[Impact of anaesthesia management on post-surgical ventilation in post-anaesthesia care unit]. / Impact de la prise en charge anesthésique sur la ventilation postopératoire en salle de surveillance postinterventionnelle.

INTRODUCTION: Control of residual muscle paralysis and hypothermia reduce postoperative complications rate. Short context sensitive half life anaesthetic agents allow a better adjustment of anaesthesia depth according to surgical requirement and a safe early extubation. Using a large clinical database, impact of these three strategies was assessed on clinical criteria such as use of neostigmine in postanaesthesia care unit (PACU), temperature, sedation score at the arrival into PACU and mechanical ventilation weaning. METHODS: This is a retrospective study on two separated periods. Since 2001, clinical events are entered into the database during and after anaesthesia in the same file. Agreement of anaesthesia staff to these strategies was assessed by the proportion of patients receiving modern anaesthetic agents (desflurane, sevoflurane and remifentanil) and the use of warming devices. Clinical impact was assessed by the number of patients receiving neostigmine in PACU, sedation score and temperature at the arrival in PACU and number of patients with mechanical ventilation in PACU. RESULTS: Between the two periods (12,033 and 11,805 patients, respectively), use of sevoflurane, desflurane and remifentanil markedly increased, as well as the use of warming devices. Number of patients with neuromuscular reversal in PACU decreased from 73 to 11 and sedation score improved dramatically. Incidence of postoperative ventilation in PACU decreased from 1.1% (n=132) to 0.2% (n=30). Incidence of postoperative hypothermia was not changed during the two periods but incidence of hypothermia in the mechanically ventilated patient increased from 34.1 to 46.6%. Length of stay in PACU decreased from 122 to 114 minutes (p<0.05). DISCUSSION: Implementation of new intraoperative protocols induced major effects on postoperative clinical parameters and especially postoperative mechanical ventilation. Failure of our hypothermia prevention associated with a fast return of consciousness lead to wean from mechanical ventilation hypothermic patients. Risks of this strategy were not estimated.

[Failure to perform auto-test of anaesthesia machine at the opening of the operating room]. / Défaut de réalisation de l'autotest de la machine d'anesthésie à l'ouverture de la salle d'opération. Étude des pratiques.

BACKGROUND: controls performed at the opening of the operating room include the anesthesia machine auto-test. Omitting the preoperative checklist is unsafe for the patient and increases the risk of possible breakdowns. The purpose of this study was to evaluate the incidence and the situations in which the auto-test of the machine was not performed at the opening of the operative room. METHODS: from a database including 55 195 cases between 1st January 2002 and 31st July 2009, a query identified cases in which the auto-test of the anaesthesia machine was omitted and the cases in which anaesthesia was made in spite of the failure of this test. Clinical circumstances were analyzed and anaesthetist and/or nurse anaesthetist were identified from the computerized anaesthesia record. RESULTS: one hundred and ninety cases (1.24%) were identified. Seventy-three percent of the omissions of the auto-test occurred while on duty whereas 85% of the failures of the auto-test took place at the beginning of the scheduled program. Individual factor was identified since three anaesthesiologists out of 22 were responsible for 49% of omissions on duty and one nurse anesthetist was responsible for 18% of the use of a failed machine and 30% of the omission of the auto-test. CONCLUSION: the auto-test of the anesthesia machine was correctly made in most cases but there are still situations where the checklist wasn't carried out. Therefore, the human factor seems important and justifies to be taken into account.

[Benchmark of a high-frequency jet ventilator, the Monsoon™]. / Étude d'un respirateur de jet-ventilation, le Monsoon™, sur banc d'essais.

OBJECTIVE: To test a high-frequency jet ventilator, the Monsoon™ (Acutronic laboratory) on a lung model with regard to delivered tidal volume and tracheal pressure measured through the injector. STUDY DESIGN: Benchmark study. MATERIAL AND METHODS: The jet ventilator was tested with seven commercially available catheters associated with their connecting line. Recorded data were: the injected volume per minute, the pressure measured in the connecting line between the ventilator and the injector and the difference between the end expiratory pressures (EEP) measured by the ventilator through the injector and the tracheal pressure. Measurements were performed by varying the driving pressure (P(w): 1 to 3 bar), inspiratory time/ventilatory cycle duration ratio (I/T: 0.25 to 0.35 %) and respiratory rate (RR 60 to 300 c/min). RESULTS: Whatever the injection catheter used, minute volume increased proportionally with P(w). For each injector and for a given P(w) and I/T, it was possible to determine a RR threshold upon tracheal pressure and EPP gradient largely increased: RR less than 3Hz for I/T less than 0.35 % and P(w) of 3 bar with adult catheters except for Leadercath(®) (RR 2Hz). All the paediatric catheters could be used at a P(w) less than 2 bar, a RR 120 c/min and I/T less than 0.35 %. CONCLUSION: Use of a dedicated injector line and a range of settings (RR and I/T rapport) are required to measure an actual EPP through the injector.

[Guide for the use of jet-ventilation during ENT and oral surgery]. / Guide d'utilisation de la jet-ventilation en chirurgie ORL, trachéale et maxillo-faciale.

The aim of this synthesis was to give recommendations on the use of jet-ventilation during ENT surgical and endoscopy procedures. Literature was collected from PUBMED and analysed by the members of French association of anaesthesiologists in ENT surgery, all skilled in this field. Presentation of these recommendations was given during the general assembly held in Reims, the 15th May 2009. Jet-ventilation is especially indicated during upper airway endoscopy and laryngeal invasive endoscopic surgery. Furthermore, transtracheal jet ventilation is included on most of difficult oxygenation and difficult intubation algorithm. The main risk of jet-ventilation is pulmonary barotrauma when expiration of injected gas is impeded by an upper airway obstruction. Failure and complications of tracheal puncture are rare when performed by experimented operators. Clinical use of jet ventilation requires a dedicated device. Practice of jet ventilation without intubation may be dangerous when applied without control of driving pressure and end expiratory tracheal pressure. Every anaesthetist should be familiar with transtracheal ventilation since they may face a "cannot ventilate cannot intubate" situation. Upper airway endoscopy and laryngeal surgery are the ideal field for training jet ventilation, even more so as this technique offers perfect operative conditions. To apply this project, jet ventilation should be used more frequently in routine practice. To maintain skill, regular use of these techniques is required.

Incidence of severe postoperative pain after cancer surgery despite intraoperative anticipation: a case controlled study.

BACKGROUND AND METHODS: Anticipating postoperative pain is a routine practice in our institution. As part of a quality assurance program we used our computerized anesthetic record system database to evaluate incidence of patients having very severe postoperative pain (grade 4 on a subjective pain scale ranging from 0 to 4) in the Post Anesthetic Care Unit during a two year period. These patients were compared to a control group matched on age, type and date of surgery. Demographic characteristics, type and duration of the surgery, preoperative and intra-operative medications were compared between groups. RESULTS: 78 patients out of 12,510 (0.6%) with a pain score of 4 were compared to another group of 78. No significant difference was observed with regards of demographic characteristics, duration, type of surgery, and operative pain medications. Pain scores and morphine consumption were significantly higher in the cases study group in comparison to the controlled group, 4 vs 1.6+/-1.1, (p<0.05) and 13.2+/-6 vs. 6.9+/-7mg (p<0.05). Patients in the cases study group had significantly more preoperative psychoactive medication: antidepressant and benzodiazepine 13 vs. 2, (p<0.05). CONCLUSION: The incidence of severe postoperative pain scores were less than 1% in our institution. In patients with preoperative opioid treatment, adaptation of analgesic treatment has probably prevented the occurrence of severe pain. Multimodal anticipation of postoperative pain should remain mandatory while efforts should focus to identify such patients before surgery.

[Residual curarization and pharyngeal muscles: remain vigilant!]. / Curarisation résiduelle et musculature pharyngée: restons vigilants!

The different concepts treating of "residual curarization" were presented according to two directions: the analysis of their contents--epidemiologic, clinical, instrumental--and the description of the pharyngeal striated muscles functions in these contexts. It appears that certain, too marked, "residual curarization" levels remain a well-evidenced factor increasing some morbidities in numerous clinical situations. All the methods of instrumental monitoring of the level of curarization--mecanography, electromyography, accelerometry--appeared useful to document the levels of "residual curarization" before patient's extubation or awakening. Today, for our speciality, it became particularly clear that: neither the selected muscle-- adductor pollicis--, neither the test currently privileged--train-of-four 2Hz--, nor the thresholds currently selected--0.90 or 1.00--did not constitute the unavoidable proof of a "residual curarization" complete absence. For the healthy volunteer receiving a curare, a train of four of the adductor pollicis greater than 0.90 can exist in presence of spirometric alterations evidencing the lack of adequate pharyngeal dilatation. In daily routine, the pharyngeal control is already disturbed by numerous molecules including: benzodiazepines, halogenated vapours, propofol, i.e. even under non-hypnotic concentrations. Faced to such evidences, our medical speciality will, undoubtedly, have to acquire new knowledge to develop muscle relaxant management control processes eliminating the surmorbidities related to "residual curarization". These tests must be validated also to exclude morbidity-prone dysfunctions of the pharyngeal striated muscles. Considering this new paradigm would be a major safety evolution for our speciality.

[Impact of a quality assurance program on the use of neuromuscular monitoring and reversal of muscle relaxants]. / Impact d'une démarche d'évaluation des pratiques professionnelles sur l'utilisation du monitorage de la curarisation et l'antagonisation des curares.

INTRODUCTION: As part of a quality assurance in the anaesthesia department, this study was designed to enhance the rate of neuromuscular blockade monitoring for patients receiving muscle relaxant during anaesthesia. METHODS: After approval of our local ethical committee, we assessed 200 computerized anaesthesia records in which neuromuscular relaxants were used. The following data were collected: demographic characteristics, durations of anaesthesia and surgery, use of neuromuscular monitoring, reversal agents and the quality of neuromuscular monitoring. The results were discussed with all anaesthesia providers of the department and an internal guideline was elaborated with the endpoint that all patients having muscle relaxants should have quantitative neuromuscular monitoring. Six months later, another assessment of 200 consecutive records collected the same data to check the efficiency of the elaborated guideline. RESULTS: The monitoring rate was of 67% at the first assessment and increased to 94% (p<0.05). The reversal rate was at 48% in the first assessment and was stable at the second assessment (50%). The rate of patients not monitored and not reversed decreased from 5 to 2% (p<0.05). DISCUSSION: This study shows that as part of a quality assurance program systematic quantitative monitoring of neuromuscular blockade can be significantly increased.