Heterogeneity in meta-analyses of treatment of acute postoperative pain: a review.

BACKGROUND: Heterogeneity and its causes must be assessed using meta-analyses (meta-analysis). Especially in meta-analysis dealing with treatment of acute postoperative pain, the type of surgery is a source of heterogeneity. We aimed to assess whether the type of surgery is considered a source of heterogeneity in meta-analysis and how it is taken into account in meta-analysis evaluating the efficacy of treatment of acute postoperative pain. We further compared meta-analysis that pooled trials of surgeries with highly heterogeneous postoperative pain levels, the heterogeneous group, with meta-analysis that pooled trials involving surgeries with homogeneous pain levels, the homogenous group. METHODS: The meta-analysis reports available in Issue 3, 2011 of the electronic database of the Cochrane library and pooling results of randomized or quasi-randomized controlled trials that assessed the efficacy of treatment of acute postoperative pain alone were considered. A survey of experts established a rating of the postoperative pain levels for the type of surgery. For each meta-analysis, the different pain level ratings associated with the trials included in the meta-analysis were considered and the standard deviation (sd) of these ratings calculated. From the distribution of sd values, we defined the heterogeneous and homogeneous groups. RESULTS: Sixty-one meta-analyses were included; all assessed heterogeneity. Twenty-six meta-analyses considered the type of surgery as a subgroup (50% vs 38% in the homogeneous group vs heterogeneous group). Forty-four reports discussed the type of surgery as a source of clinical heterogeneity (85% vs 62% for the homogeneous vs heterogeneous group). Twenty-nine meta-analyses compared 'postoperative pain from dental surgery' to 'other type of surgery'. CONCLUSIONS: Meta-analyses evaluating treatment of postoperative pain should explore clinical heterogeneity associated with the type of surgery for better implications for practice.

[Percutaneous mandibular nerve block using neuro-stimulation guiding through the sigmoid indentation in facial surgery]. / Bloc percutané du nerf mandibulaire à travers l'échancrure sigmoïdienne, guidé par neurostimulation, en chirurgie de la face.

INTRODUCTION: Mandibular nerve block is a simple and effective but rarely used technique. It decreases peri-operative pain in mandibular osteotomy. It improves surgical field visibility by decreasing bleeding. Mandibular nerve block allows cutaneous surgery without general anesthesia and is one of the alternative treatments for chronic facial pain. TECHNICAL NOTE: The mandibular nerve is located using a needle connected to a neurostimulator. After local disinfection, a neurostimulation needle is inserted below the zygomatic arch, between the coronoid apophysis in front, and the condyle process in back, with a 45 to 60° angle. The needle is pushed to a 40 mm depth. Masticator muscle contraction confirms mandibular nerve stimulation. After a careful negative aspiration, 5 mL of ropivacaine 0.5% are injected slowly, and in increments. DISCUSSION: The complications with this technique, such as failure or arterial puncture, are rare and limited if a nerve stimulator is used. Patient's comfort is improved by intravenous remifentanil sedation in target control infusion mode, associated to prior use of prilocaine and lidocaine cutaneous cream.

Modification of Tp-e and QTc intervals during caesarean section under spinal anaesthesia.

There are no guidelines for the anaesthetic management of caesarean section in women with long QT syndrome; the description of myocardial ventricular repolarisation in healthy women during caesarean delivery could be a first step. The aim of this study was to describe modification of the QT interval, corrected for heart rate, and the interval between the peak and the end of the T-wave (Tpeak-Tend interval) during caesarean section under spinal anaesthesia. We studied 40 patients scheduled for caesarean section under spinal anaesthesia. Patients were randomly assigned to receive either ephedrine or phenylephrine to prevent hypotension. We injected 5 IU oxytocin after delivery. Corrected QT and Tpeak-Tend intervals were unchanged from pre-operative values after induction of spinal anaesthesia, but increased significantly after oxytocin injection. The choice of vasopressor did not affect the Tpeak-Tend interval. The risk-benefit balance of oxytocin bolus during caesarean delivery should be discussed with women with a history of long QT syndrome.

[Relapsing polychondritis: a possible cause of difficult extubation]. / Polychondrite atrophiante: une cause possible d'extubation difficile.

We report the case of a 54-year-old woman suspected of relapsing polychondritis who underwent a nasal septum biopsy under general anaesthesia. Tracheal intubation was unremarkable, but extubation attempts failed because of upper airway inspiratory collapse induced ventilatory distress. Definitive tracheostomy placement was mandatory. Cartilage biopsy confirmed severely developed relapsing polychondritis. Even though relapsing polychondritis is rare, anaesthesiologists should be aware of this pathology and preanaesthetic evaluation may focus on particular risks associated with upper airway cartilaginous structure anatomical and histological modifications.

[Impact of Cormack and Lehane's grade on Intubating Laryngeal Mask Airway Fastrach using: a study in gynaecological surgery]. / Impact du grade de Cormack et Lehane sur l'utilisation du masque laryngé Fastrach: étude en chirurgie gynécologique.

OBJECTIVE: To evaluate the impact of Cormack and Lehane grade on the Intubating Laryngeal Mask Airway (LMA-Fastrach) using in women. STUDY DESIGN: Open prospective study. PATIENTS: The study included 115 scheduled gynaecologic surgery women. METHODS: An LMA-Fastrach was systematically performed in patients with a Cormack's grade > or =3 or when Arne's score was > or =7 whatever the Cormack. After induction of anaesthesia and neuromuscular blockade, Cormack's grade was assessed and LMA-Fastrach was inserted. Proper insertion was confirmed by the easiness of assisted ventilation and the normal aspect of the capnographic curve. Intubation through the LMA-Fastrach was carried out with the specific kit's endotracheal tube. More than two attempts were considered as a failure of the technique and an alternative method was performed. The following parameters were noted: age, weight, height, clinical predictors for difficult intubation (Arne et al.'s score), number of LMA-Fastrach insertion, ventilation efficiency through LMA-Fastrach, successful intubation with LMA-Fastrach and oesophageal intubation. RESULTS: Ventilation through the LMA-Fastrach was efficient in 97%. The success rate of intubation was 94.8% (86% on the first attempt). The success rate of ventilation and intubation were not statistically different according to the different Cormack's grades. The obesity (BMI>30) did not change the success rate of ventilation and intubation through the LMA-Fastrach. CONCLUSION: In women with either predicted or unpredicted difficult intubation, the success rates of ventilation and intubation through the LMA-Fastrach don't seem to be influenced by Cormack grade and obesity.

Hemodynamic consequences of increasing mean airway pressure during high-frequency jet ventilation.

Six critically ill patients with acute respiratory failure were ventilated using high-frequency jet ventilation (HFJV)-frequency 100.min-1, driving pressure 35 psi, 1.8 mm inside diameter injector cannula. Hemodynamic measurements using radial artery and Swan-Ganz catheters, esophageal pressure (EP), and mean airway pressure (Paw) were measured at four different I:E ratios: 0.25, 0.43, 0.67 and 1.0. Static respiratory compliance, using the super syringe method, was measured during intermittent positive pressure ventilation (IPPV) and during HFJV. The results suggested that decreased venous return, increased right ventricular afterload, and decreased PaCO2 accounted for the decrease in cardiac index observed during HFJV using elevated I:E ratios. These variations, related to marked increases in intrathoracic pressures, are very similar to those observed during conventional ventilation with PEEP.

A comparison of direct, indirect, and fiberoptic laryngoscopy to evaluate vocal cord paralysis after thyroid surgery.

After thyroidectomy, the anesthesiologist usually performs a laryngoscopy to detect laryngeal edema and nerve palsies. The goal of this study was to compare three different methods of laryngeal examination after tracheal extubation of the patients. For that purpose, between 1990 and 1995, a prospective series of 1608 patients operated for thyroidectomy has been studied. The series was divided into 4 groups. In group I (n = 200), four anesthesiologists have evaluated the efficiency of the immediate postextubation direct laryngoscopy. In group II (n = 100), one anesthesiologist has compared the direct, indirect, and flexible laryngoscopies in every patient in a fixed and timed fashion. In group III (n = 100), the four examiners have evaluated the flexible laryngoscopy at a different timing so as to eliminate the possible temporal relationship of the ease of visualization in group II. In group IV (n = 1208), the four examiners have evaluated flexible laryngoscopy, on a large scale, at any time during the 1-h stay in the recovery room. Special attention was directed to the patients with known cardiovascular diseases. Direct and indirect laryngoscopies were only effective in 76 and 73%, respectively, of the patients, whereas flexible laryngoscopy was effective in 99.6% of them. Flexible laryngoscopy was easy to perform in 96.5% of the patients versus 65 and 55% with direct and indirect laryngoscopies. Finally, variations in monitored cardiovascular parameters were significantly lower with flexible and indirect laryngoscopies than with direct laryngoscopy. These mild variations induced by flexible laryngoscopy were well tolerated by patients with known cardiovascular diseases. Flexible laryngoscopy is the best method for an immediate laryngoscopic examination after thyroidectomy.

Airway complications in thyroid surgery.

Perioperative and postoperative morbidity and mortality were studied in a series of 3,008 thyroidectomies. Compressive symptoms, frequent in substernal and cancerous goiters, were present in 11.0% of the patients, although a low rate of dyspnea (2.7%) was observed. In large goiters, some orotracheal intubations were difficult. In such cases, the transtracheal approach can also be difficult, so failure should be anticipated. Postoperative causes of respiratory obstruction included local hemorrhages, bilateral recurrent nerve palsies, and laryngeal edema. A tracheal collapse was not observed. These respiratory obstructions led to repeat surgery in 11 patients, tracheostomy in 3, and temporary reintubation with steroid therapy in 1. The recurrent laryngeal nerve, which may have been affected preoperatively, was found to be damaged postoperatively in 0.5% of the patients with benign goiters, compared to 10.6% of the patients with thyroid cancer. In this last group a bilateral palsy was observed in 3 cases with prolonged or extensive surgery. After these short-term orotracheal intubations (114 minutes on average), injuries of the airway caused by the endotracheal tube were found in 4.6% of the patients.

Pharmacokinetics of lidocaine with epinephrine in piglets following epidural anaesthesia.

The time course of arterial plasma lidocaine concentration, following an epidural anaesthesia via the sacrococcygeal or the S4-S5 trans-sacral approach, was studied in nine healthy piglets (7.8 +/- 1.3 weeks). Plasma lidocaine concentrations were measured for up to six hours after administration (5 mg/kg). Peak plasma concentration was 1.83 +/- 0.17 mg/l. Pharmacokinetic parameters determined from an independent compartment model were not different from those observed after an epidural administration of lidocaine via the sacrococcygeal space in children, except for a wide variability in the time taken to reach the maximum concentration (27.3 +/- 7.4 min) and a shorter half-life of elimination (82.8 +/- 7.0 min). The total body clearance of lidocaine was similar in piglets (17.3 +/- 1.6 ml/min/kg) to that in children. The shorter half-life of elimination was therefore attributed to a smaller volume of distribution in piglets (2.0 +/- 0.2 l/kg).

Postthyroidectomy analgesia: morphine, buprenorphine, or bupivacaine?

STUDY OBJECTIVE: To compare three analgesic regimens for pain relief after thyroidectomy. DESIGN: Randomized, double-blind, placebo-controlled study. SETTING: Inpatient anesthesia in a university department of endocrine surgery. PATIENTS: 342 patients scheduled for elective thyroidectomy with nitrous oxide-oxygen-isoflurane anesthesia in addition to fentanyl. INTERVENTIONS: Group 1 received preoperative oral controlled release morphine 10 mg, and Group 2 received postoperative sublingual buprenorphine 0.2 mg. Group 3 received 0.25% bupivacaine (10 ml) wound infiltration before skin closure. Eight hours after tracheal extubation, patients received a second dose of the same drug in each group except in Group 3, where medication was changed to sublingual buprenorphine 0.2 mg. MEASUREMENTS AND MAIN RESULTS: Patients in Group 2 required fewer additional analgesics: 0.54 +/- 0.68 vs. 0.96 +/- 0.84 in Group 1 and 0.79 +/- 0.78 in Group 3. Patients in Group 2 demonstrated a better pain score and this group showed a higher percentage of satisfied patients: 96% vs. 85% in Group 1 and 91% in Group 3. Group 2 also included more patients requiring no analgesics: 56% vs. 32% in Group 1 and 42% in Group 3. The side effects in all three groups did not differ. CONCLUSION: The administration of sublingual buprenorphine after thyroidectomy provides better analgesia than small doses of oral controlled-release morphine or than 0.25% bupivacaine wound infiltration at the end of surgery.

[Anesthesia and factor VII deficiency]. / Anesthésie et déficit en facteur VII de la coagulation.

A case is reported of a 17 year-old patient undergoing emergency internal fixation of a mandibular fracture after a road traffic accident. Routine preoperative blood analysis revealed an isolated deficiency in factor VII (33%), with a normal activated partial thromboplastin time and a reduced prothrombin level (50%). Because there was no previous history of an haemorrhagic diathesis, the surgical procedure was carried out without any factor VII replacement. The course of surgery was normal, with no abnormal blood loss. The possible causes of this deficiency, and its treatment are discussed.

[Proposal for a new multifactor screening score of difficult intubation in ORL and stomatognathic surgery: preliminary study]. / Proposition d'un nouveau score multifactoriel de dépistage de l'intubation difficile en chirurgie ORL et stomatologique: étude préliminaire.

This study assessed prospectively in 295 ENT adult patients the predictive value of clinical indicators for difficult intubation and of a new multifactorial score, established by the allocation of points (0, 3, 5 or 7) depending on the degree of presence of seven factors: pathology known to be associated with a difficult intubation, clinical signs of airways' pathology, inter-incisors gap and mandible's luxation, submental mandibular-thyroid distance, normal or short and broad neck, head and neck movements, and Mallampati's test. The incidence of difficult laryngoscopy was 14% and the use of particular techniques for tube insertion was required in 8% of patients. The presence of malformation or pathology often associated with a difficult intubation and the presence of functional signs of airways' pathology predict the difficulties of laryngoscopy and tracheal intubation with a good sensitivity and specificity. The analysis of the "Receiver Operating Characteristic curves" showed that a score higher or equal to 11 allows the prediction of difficult intubations with a sensitivity of 96% and a specificity of 90%.

[Which propofol target concentration for ASA III elderly patients for conscious sedation combined with regional anaesthesia?]. / Quelle concentration cible pour le propofol chez le sujet âgé ASA III pour la sédation légère en complément d'une anesthésie locorégionale?

OBJECTIVE: To determine the optimal propofol target concentration between 0.9-1.1 and 1.3 mg l(-1), for conscious sedation and amnesia using Diprifusor in ASA III patients over 60 years. STUDY DESIGN: Prospective study. PATIENTS AND METHODS: In ASA III patients over 60 years presented for elective vascular procedures under regional anaesthesia, sedation was induced with propofol TCI by increasing target concentrations from 0.9 to 1.3 mg l(-1) by 0.2 mg l(-1) steps up to a sedation score corresponding to light level (patient awakable with tactile stimulation). At baseline and each step, specific pictures were shown to the patient and clinical parameters and unwanted side effects occurrence were recorded. In PACU, memorisation of pictures and events was looked for. RESULTS: Conscious sedation was obtained in 100% of the patients at 0.9 mg l(-1), 94% at 1.1 and 78% at 1.3 mg l(-1). Amnesia was concentration-dependent and for each concentration was always more important for pictures than for events. Haemodynamic parameters did not change significantly. Incidents occurred in 12% of cases at 1.1 and 39.4% at 1.3 mg l(-1). DISCUSSION: None of those three concentrations was satisfying in 100% of cases for the three criterias (sedation < S2, amnesia and none side effects). These results suggest that propofol target concentration 0.9 microg ml(-1) could be used safely for sedation in elderly ASA III patients. Moreover, we have shown that amnesia for events requires higher propofol concentrations than amnesia for pictures during conscious sedation.

[Cocaine contact anesthesia for endonasal surgery. Kinetics and clinical tolerance of a concentrated solution]. / Anesthésie de contact à la cocaïne pour chirurgie endonasale. Cinétique et tolérance clinique d'une solution concentrée.

OBJECTIVE: To assess the pharmacokinetics and clinical tolerance of a 33% cocaine solution administered topically for intranasal surgery. STUDY DESIGN: Clinical prospective open trial. PATIENTS AND METHODS: Twelve ASA I patients scheduled for intranasal surgery were sedated with midazolam 2 mg and fentanyl 50 micrograms. Topical anaesthesia was obtained with aqueous 33% cocaine HCl 360 mg, lidocaine HCl 140 mg, adrenaline 0.04 mg and naphazoline 0.4 mg. Venous blood samples were taken before cocaine application and 15, 30, 45, 60, 90, 120, 150, 180, 240 min later. The plasma was immediately separated and the samples were frozen. The concentration of cocaine was measured by HPLC. Potential cardiotoxic and neurotoxic effects were clinically monitored. RESULTS: The mean dose of cocaine applied was 5.85 +/- 1.3 mg.kg-1 and the dose actually delivered was 4 +/- 1.5 mg.kg-1. The Cmax was 859 +/- 503 ng.mL-1 after a Tmax to 47 +/- 17 min. The mean elimination half-life was 87 +/- 19 min (mean +/- SD). The total clearance and the volume of distribution were respectively 4,521 +/- 1,858 mL.min-1 and 568 +/- 273 L. No clinical evidence of toxicity was found. CONCLUSIONS: This study shows that it is possible to perform major intranasal surgery under topical anaesthesia with a concentrated solution (33%) of cocaine at a high dose (6 mg.kg-1). These results differ completely with data obtained in addicts.

[Clonidine combined with flunitrazepam before carotid endarterectomy decreases cerebrovascular CO2 reactivity]. / La clonidine associée au flunitrazépam avant endartériectomie carotidienne diminue la réactivité cérébrovasculaire au CO2.

OBJECTIVE: Assess cerebrovascular CO2 reactivity changes using transcranial Doppler sonography (TCD) after oral premedication associating clonidine (2 micrograms.kg-1) and flunitrazepam (70 micrograms.kg-1) in patients scheduled for carotid stenosis surgery. STUDY DESIGN: Prospective study, not randomized, the patient being his own "control". PATIENTS AND METHODS: Thirteen patients undergoing carotid endarterectomy under cervical plexus block were included. The monitoring included: automated arterial pressure cuff, ECG, radial artery catheter, TCD with probe secured in temporal window. The study of the cerebrovascular CO2 reactivity was performed with TCD recording on the side of operation, on the day before, and on the day of carotid endarterectomy, 90 min after the premedication, immediately before surgery. To change PaCO2, four ventilatory states were successively performed: (1) normoventilation, (2) hyperventilation, (3) hypoventilation, (4) "breath-holding test". At each state, it was noted: HR, MAP, PaCO2, mean blood flow velocity in the middle cerebral artery (Vm-MCA), resistance index of Pourcelot (RI), cerebrovascular reactivity (slope Vm-MCA/PaCO2). The results (+/- SEM) were analyzed by Wilcoxon test or t test. RESULTS: After premedication, cerebrovascular CO2 reactivity decreased (0.043 +/- 0.019 vs 0.034 +/- 0.013; p < 0.05) without modification of RI (0.578 +/- 0.291 vs 0.612 +/- 0.025; NS). No complication during carotid clamping was reported. CONCLUSION: Inclusion of clonidine in premedication before carotid stenosis surgery must be questioned because a decrease of cerebrovascular CO2 reactivity could be deleterious in case of intraoperative stroke.

[Transfusion-associated HIV contamination between January 1980 and September 1985]. / Contamination transfusionnelle par le VIH de janvier 1980 à septembre 1985.

This study reports the results of a retrospective survey of transfusion-related HIV-contamination in patients who were admitted in our neurosurgery department, between the 1st January 1980 and the 30th September 1985. In our area of France, the risk of HIV-contamination is low. During this 5-year-period the blood donors were not tested for HIV. Six hundred twenty-one patients were identified from the operating room registers. The administered blood components were always noted in these registers for each patient. Among these 621 patients, 233 died rapidly. Three hundred eighty files were taken out from the central archives' department. Eight files could not be found. These 380 files were examined for the patient's address, or the family's one, or the regular doctor's name and address. A letter was sent to the latter in order to inform him about the patient's transfusion. The doctor had to ask the patient to order a HIV-test. A recall letter was sent 8 months later as required. The patients who did not have a regular doctor were contacted directly by phone or letter, or indirectly through their family. Thirteen months after the beginning of this survey it was established that 334 patients died (53.5%) and only 151 patients were found and tested. One of them was HIV-positive. As this patient suffered from a hemophilia B, he had been medically followed and his positive serology was known since 1988. It was impossible to get any answer from 136 other patients who represent 22% of all patients and 47% of still alive patients or supposed to be so.(ABSTRACT TRUNCATED AT 250 WORDS)

[Prevention of per-operative myocardial ischemia with continuous nitroglycerin infusion]. / Prévention de l'ischémie myocardique per-opératoire. Emploi d'une perfusion continue de trinitrine.

The aim of this work is to assess the possible beneficial effects of intra and post operative nitroglycerin infusion in patients with disabling angina pectoris (Class III of the New-York Heart Association). We thus compared the occurrence of myocardial ischemia detected by means of continuous electrocardiographic recording of lead V5 in 31 patients which were divided in two groups. The control group (I) included 16 patients, group II included 15 patients undergoing similar surgical procedures, given a permanent nitroglycerin infusion. Mean dose of nitroglycerin was 0,91 +/- 0,18 micrograms . kg-1 . min-1. An ischemic type S T segment depression occurred in 15 out 16 patients in group I and in only 3 out of 15 patients in group II (p less than 0,001). No S T segment depression occurred following a decrease of more than 25 p. 100 in systolic blood pressure in 8 patients of group II at the time of induction. These hypotensive episodes were easily corrected by decrease of the nitroglycerin infusion rate associated with a rapid blood volume expansion. The very high incidence of intra operative myocardial ischemia in control group demonstrates the severity of the coronary disease in the observed patients. The significantly lower frequency of ischemic S T segment depression observed in the patients given nitroglycerin infusion suggests that this drug is highly effective in preventive myocardial ischemia in patients with severe coronary artery disease. The administration of nitroglycerin in our patients had been easy to control, blood pressure reaching normal value within a few minutes after decrease of the rate of drug infusion when needed.

[Hemodynamic effect of the clamping of the carotid in the surgically treated coronary patient]. / Retentissement hémodynamique du clampage de la carotide chez l'opéré coronarien.

To determine both the incidence of myocardial ischaemia and haemodynamic response to carotid cross-clamping in coronary artery disease, 30 patients undergoing carotid endarterectomy were studied with a clear history of effort related disabling angina pectoris. Myocardial ischaemia was detected by a recording of lead CM5 of the electrocardiogram. A radial arterial and a thermodilution pulmonary catheter were inserted to obtain haemodynamic measurements before and after carotid cross-clamping and unclamping. Anaesthesia was induced with increments of thiopental, fentanyl 6 micrograms X kg-1 and pancuronium. Additional fentanyl (2 micrograms X kg-1) was injected before skin incision and before carotid cross-clamping. Carotid cross-clamping results in a significant increase in both mean arterial blood pressure and capillary wedge pressure. Two patients experienced myocardial ischaemia with ST segment depression during carotid cross-clamping. Nitroglycerin infusion led to the improvement of ST segment depression. When halothane was additionally administered to patients who developed hypertension in response to carotid cross-clamping, arterial blood pressure returned to normal value. These results indicate that carotid cross-clamping increases determinants of myocardial oxygen demand and may cause myocardial ischaemia in patients suffering from angina pectoris.