Cyrus Motamed

Possible mitigation of rocuronium-induced anaphylaxis after administration of sugammadex.

Sir, We describe a case of rocuronium-induced anaphylaxis, which was possibly mitigated after administration of sugammadex. A 61-year-old woman (45 kg, 155 cm) was scheduled to have bone cementoplasty for pain reduction in relation to bone metastasis of a thyroid cancer. She previously had multiple thyroid surgeries without any allergy report and a history of hypertension. Her medication included propranolol, L-thyroxine, and opioids for chronic pain.

Sensibilité à l’atracurium des muscles abdominaux latéraux

OBJECTIVE: To study the effect of atracurium on the electromyographic activity of the lateral abdominal muscles and adductor pollicis in anaesthetized subjects. STUDY DESIGN: Prospective, comparative, open study. PATIENTS AND METHODS: Sixteen patients, ASA physical status 1 or 2, undergoing elective orthopaedic surgery under general anaesthesia were studied. Anaesthesia was induced with propofol/fentanyl and orotracheal intubation performed after glottic local anaesthesia without using muscle relaxant. Anaesthesia was maintained with isoflurane/nitrous oxide/oxygen and fentanyl reinjections. Supramaximal percutaneous stimulations in a simple twitch mode (0.1 Hz) were applied at the 9th-10th intercostal nerve on the posterior axillary line and at the ulnar nerve at the wrist. The electromyographic responses were registered using skin surface electrodes, placed on the D9-D10 dermatome in regard of the lateral abdominal muscles and of the thenar muscles. After a single bolus dose of atracurium 0.5 mg.kg-1, the following parameters were studied: the maximum effect (Emax), the time for obtaining Emax (Delay) and the recovery time of 5, 10, 25, 50, 75 and 100% of the control neuromuscular response (T5, T10, T25, T50, T75, T100). RESULTS: The dose of 0.5 mg.kg-1 of atracurium induced 100% block in both lateral abdominal muscles and adductor pollicis. Lateral abdominal muscles blockade had faster onset (136 +/- 4 s versus 205 +/- 29 s) and shorter recovery, T5, T10, T25, T50, T75 and T100 were significantly (p < 0.05) shorter than at the adductor pollicis. CONCLUSION: Lateral abdominal muscles blockade have faster onset and recovery than adductor pollicis.

Survey of muscle relaxant effects management with a kinemyographic-based data archiving system: a retrospective quantitative and contextual quality control approach.

In a retrospective quality control study of muscle relaxant management, we assessed unbiased files provided by an automatic archiving system using quantitative monitoring generated by a kinemyographic transducer and suggest improvements for a possible future design. 200 randomly selected files were double checked to collect the values of twitch height ratio (THr), train of four ratio (TOFr) and TOF count in four periods: references values acquisition (REF), maximal level of paralysis, paralysis maintenance, pre-tracheal extubation residual paralysis assessment (RPA). The parameter values were selected according to period-specific predefined rules. A quantitative quality control was based upon standardized cut-offs values. A contextual quality control was based upon the detection of “difficult-to-interpret” episodes. Results were expressed on a descriptive basis only. For the REF period, THrs and TOFrs were lacking in, respectively, 47 and 18 of the 200 recordings analysed. A starting TOFr above 0.90 existed in 119 files. Concomitant THrs and TOFrs >0.90 were evidenced 93 times. During RPA period, TOFr >0.90 was recorded on 82 occasions. The optimal combination of THr >0.80 and TOFr >0.90 was detected in 30 files only. Presence of “difficult to interpret” episodes started with 18 files for the REF period and increased to 42, 86 and 52 in the subsequent ones most of them probably related to the absence of initial calibration procedure. In the real life conditions, a near to optimal quality control is not always observable with the quantitative neuromuscular monitoring studied. To improve the NMT monitoring, the calibration of the sensor should be performed vigorously by the anaesthesia provider and the quality of this calibration must be displayed on the screen of the monitor.

An anaesthesia information management system as a tool for a quality assurance program: 10 years of experience

INTRODUCTION Anaesthesia Information Management Systems (AIMS) generate large amounts of data, which might be useful for quality assurance programs. This study was designed to highlight the multiple contributions of our AIMS system in extracting quality indicators over a period of 10years. METHODS The study was conducted from 2002 to 2011. Two methods were used to extract anaesthesia indicators: the manual extraction of individual files for monitoring neuromuscular relaxation and structured query language (SQL) extraction for other indicators which were postoperative nausea and vomiting (PONV), pain, sedation scores, pain-related medications, scores and postoperative hypothermia. For each indicator, a program of information/meetings and adaptation/suggestions for operating room and PACU personnel was initiated to improve quality assurance, while data were extracted each year. RESULTS The study included 77,573 patients. The mean overall completeness of data for the initial years ranged from 55 to 85% and was indicator-dependent, which then improved to 95% completeness for the last 5years. The incidence of neuromuscular monitoring was initially 67% and then increased to 95% (P<0.05). The rate of pharmacological reversal remained around 53% throughout the study. Regarding SQL data, an improvement of severe postoperative pain and PONV scores was observed throughout the study, while mild postoperative hypothermia remained a challenge, despite efforts for improvement. DISCUSSION The AIMS system permitted the follow-up of certain indicators through manual sampling and many more via SQL extraction in a sustained and non-time-consuming way across years. However, it requires competent and especially dedicated resources to handle the database.

Postoperative nausea and vomiting in the post-anesthetic care unit, a 5-year survey of a quality assurance program in surgical cancer patients

INTRODUCTION PostOperative Nausea and Vomiting (PONV)is a major side effect related to surgery and anesthesia. Our institution is equipped with Anesthesia Information Management System (AIMS). We used this database to assess and follow the effect of our quality assurance program for PONV. METHODS Our AIMS system permits automatic storage of vital signs while other information are indexed by anesthesia providers and PACU personnel. Intra-operative and PACU events were extracted from a database by sequential query language (SQL) interrogation from year 2005 to 2010. A new prophylactic antiemetic protocol was issued for high-risk patients in our institution (dexamethasone, droperidol in the operating room and odansetron in the PACU) and initiated in 2006; in parallel, adjuvant measures influencing PONV were taken for anesthetic interventions. PONV scores and related medications, intra- and postoperative opioids and inhalational anesthetics consumption were extracted, and results were regularly shared with anesthesia providers and PACU personnel as part of quality assurance program. RESULTS The study concerned 40,045 patients, exhaustivity or completeness was 70% in 2005 but reached 90% in 2010. PONV scores significantly improved during the years after the instauration of the new protocol (31% in 2005 vs. 13% in 2010). Concomitantly, morphine consumption and intra-operative nitrous oxide showed a steady decrease. No significant difference was noticed in the use of inhalational anesthetics. CONCLUSION Using our AIMS database, we indirectly monitored the effectiveness of our PONV protocol but also other possible component of a multimodal approach toward these side effects.

Influence of real-time Bayesian forecasting of pharmacokinetic parameters on the precision of a rocuronium target-controlled infusion

SummaryIntroductionBayesian forecasting has been shown to improve the accuracy of pharmacokinetic/pharmacodynamic (PK/PD) models by adding measured values to a population model. It could be done in real time for neuromuscular blockers (NMB) using measured values of effect. This study was designed to assess feasibility and benefit of Bayesian forecasting during a rocuronium target-controlled infusion (TCI).MethodsAfter internal review board (IRB) approval and informed consent, 21 women scheduled for breast plastic surgery were included. Anesthesia was maintained with propofol, alfentanil, and controlled ventilation through a laryngeal mask. Rocuronium was delivered in TCI with Stanpump software and the Plaud population model. The target effect was 50% blockade until insertion of breast prosthesis; thereafter it was set to 0%. Response to train of four (TOF) at adductor pollicis was recorded using a force transducer. In ten patients, drug delivery was based on the population model. In the others, repeated measures values were entered in the software, and the PK model was adjusted to minimize the error in predicted effect. Model precision was compared between groups using mean prediction error and mean absolute prediction error.ResultsAt target 50%, model accuracy was not improved with Bayesian adjustments; conversely, post-infusion errors were significantly decreased. The first two measures had the most influence on the model changes.DiscussionBelow clinical utility, such adjustments may be used to explore cofactors influencing interindividual and intraindividual variability in NMB dose-response relationship. Similar tools may also be developed for drugs in which a quantitative effect is available, such as electroencephalography (EEG) for hypnotics.ImplicationReal-time Bayesian forecasting combining measured values of effect with a population model is suitable to guide NMB-agent delivery using Stanpump software.

Learning curves for three specific procedures by anesthesiology residents using the learning curve cumulative sum (LC-CUSUM) test

Background The learning curve cumulative sum (LC-CUSUM) test is an innovative tool that allows quantitative monitoring of individual medical performance during the learning process by determining when a predefined acceptable level of performance is reached. This study used the LC-CUSUM test to monitor the learning process and failure rate of anesthesia residents training for specific subspecialty anesthesia procedures. Methods The study included 490 tracheal punctures (TP) for jet ventilation, 340 thoracic epidural analgesia (TEA) procedures, and 246 fiberoptic nasal intubations (FONI) performed by 18 residents during their single 6-month rotation. Results Overall, 27 (14–52), 19 (5–41), and 14 (6–33) TP, TEA, and FONI procedures were performed, respectively, by each resident. In total, 2 of 18 residents achieved an acceptable failure rate for TEA according to the literature and 4 of 18 achieved an acceptable failure rate for FONI, while none of the residents attained an acceptable rate for TP. Conclusions A single 6-month rotation in a reference teaching center may not be sufficient to train residents to perform specific or sub-specialty procedures as required. A regional learning network may be useful. More patient-based data are necessary to conduct a risk adjustment analysis for such specific procedures.

Remote peripheral tissue oxygenation does not predict postoperative free flap complications in complex head and neck cancer surgery: A prospective cohort study

BACKGROUND Patients undergoing free flap reconstruction after head and neck cancer may develop free flap complications. In the perioperative period, haemoglobin content and oxygen tissue saturation (StO2) measured directly on the free flap reflect peripheral tissue oxygenation. However, in this type of surgery, StO2 cannot always be applied directly or proximate to the free flap. The aim of this study was to assess the possible value of StO2 measured at the thenar eminence and other 24hour perioperative factors on free flap complications. METHODS Inclusion criteria corresponded to patients with head and neck cancer with free flap surgery in whom direct StO2 could not be monitored on the flap nor in its peripheral area. Patient characteristics and intraoperative data, such as haemoglobin and fluid management, were prospectively collected. StO2 was measured remotely on the thenar eminence. Data were collected for 24hours and free flap complications were recorded for up to 15days after surgery. Patients were thereafter classified into two groups: with or without free flap complications and the data were compared in consequence. RESULTS Forty consecutive patients were prospectively included. Ten patients had postoperative free flap complications and were compared to the 30 other patients without complications. The haemoglobin level at the reperfusion of the flap: (AUC 0.80 [0.65-0.91], threshold 9.9g/dL, P<0.001) and body mass index [BMI] (AUC 0.80 [0.64-0.72], threshold 24.5kg/m2, P<0.01) were significantly related to complications. CONCLUSION In head and neck complex oncologic reconstructive surgery, haemoglobin and BMI were the most sensitive tools for predicting postoperative free flap complications, while thenar eminence StO2 was not.

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.

Contribution of Low-Dose Computerized Tomography With Digital Multiplanar Reconstructions in Thoracic Epidurography and Correlation With Sensory Block in Postoperative Analgesia

Background The level of sensory block in postoperative epidural analgesia has been correlated with conventional contrast epidurography in only one study, while low-dose CT scan epidurography with multiplanar reconstruction may be a better tool for this purpose. Objectives The primary objective of this study was to evaluate, by CT imaging and digital multiplanar reconstruction, the spread and distribution of contrast medium injected into the epidural space through a catheter inserted in a low thoracic position for postoperative analgesia. Materials and Methods Ten patients undergoing major abdominal cancer surgery with effective epidural analgesia were prospectively included at postoperative day three. Two consecutive boluses of 5 mL of a mixture of ropivacaine and contrast medium were injected at 15 minutes intervals into the epidural space. Multislice low-dose CT scan epidurography and an assessment of the sensory block were performed before and after injection of the second bolus. The primary objective was to assess the contribution of CT scan epidurography to predict a correlation between the level of sensory block and the spread of the contrast medium in the epidural space; the secondary objective was to determine the agreement between the two methods. Results The spread of contrast material and the clinical sensory block significantly increased after the second injection (32%; P < 0.05). However, no highly significant correlation was observed between the two methods. A gap of two spinal segments of CT opacification was observed in two patients and was confirmed by clinical assessment. Conclusions CT epidurography is not closely correlated with a clinical assessment of epidural block; thus, a clinical assessment of the sensory block is mandatory. The use of opioid analgesia in combination with local anesthetics may compensate for the lack of efficacy of local anesthetics alone.