Edgard Engelman

Effect of propofol on cerebral blood flow and metabolism in man.

Cerebral blood flow, cerebral oxygen consumption, lactate and glucose metabolism were measured in 13 patients during anaesthesia with nitrous oxide, oxygen and enflurane 0.5% and after 30 minutes infusion of propofol. The mean blood concentration of propofol was 4.06μg/ml. Cerebral blood flow decreased by 27.6% and cerebral vascular resistance by 51%. There were no changes in lactate and glucose metabolism. Cerebral oxygen consumption decreased by 18.25%. Changes in the electroencephalograph were related to the blood levels of propofol.

Different Anesthetic Techniques Associated with Different Incidences of Chronic Post-thoracotomy Pain: Low-Dose Remifentanil Plus Presurgical Epidural Analgesia is Preferable to High-Dose Remifentanil with Postsurgical Epidural Analgesia

OBJECTIVE To investigate the relationships between 2 anesthetic techniques, or the extent of allodynia around the surgical wound, and the occurrence of chronic post-thoracotomy pain. DESIGN Prospective, randomized study. SETTING A single-institution, university hospital. PARTICIPANTS Thirty-eight patients who underwent elective thoracotomy under general anesthesia. INTERVENTIONS High-dose remifentanil (average effect-site concentration 5.61 +/- 0.84 ng/mL) with epidural analgesia started and at the end of surgery or low-dose remifentanil (average effect site concentration 1.99 +/- 0.02 ng/mL) with epidural analgesia with 0.5% ropivacaine started at the beginning of anesthesia. MEASUREMENTS AND MAIN RESULTS Pain intensity and the extent of allodynia around the wound were measured during the hospital stay. The presence and intensity of residual pain were assessed 1, 3, and 6 months after surgery and at the end of the study (6-13 months, average 9 months). A DN4 neuropathic pain diagnostic questionnaire was conducted at the same times. In the high-dose group, the area with allodynia was three times larger than the area in the low-dose group. The increased allodynia was associated with a higher incidence of chronic pain (RR: 2.7-4.2) 3 and 6 months after surgery and at the end of the study (median follow-up: 9.5 months). CONCLUSIONS High-dose remifentanil (0.14-0.26 microg/kg/min) without epidural analgesia during surgery is associated with a large area of allodynia around the wound. These patients develop a much higher incidence of chronic pain than those receiving low-dose remifentanil with epidural analgesia during surgery.

Efficacy and safety of perioperative pregabalin for post-operative pain: a meta-analysis of randomized-controlled trials.

We calculated in a meta‐analysis the effect size for the reduction of post‐operative pain and post‐operative analgesic drugs, which can be obtained by the perioperative administration of pregabalin. Three end‐points of efficacy were analysed: early (6 h–7 days) post‐operative pain at rest (17 studies) and during movement (seven studies), and the amount of analgesic drugs in the studies that obtained identical results for pain at rest (12 studies). Reported adverse effects were also analysed. The daily dose of pregabalin ranged from 50 to 750 mg/day. The duration of treatment in patients assessed for pain ranged from a single administration to 2 weeks. Pregabalin administration reduced the amount of post‐operative analgesic drugs (30.8% of non‐overlapping values – odds ratio=0.43). There was no effect with 150, and 300 or 600 mg/day provided identical results. Pregabalin increased the risk of dizziness or light‐headedness and of visual disturbances, and decreased the occurrence of post‐operative nausea and vomiting (PONV) in patients who did not receive anti‐PONV prophylaxis. The administration of pregabalin during a short perioperative period provides additional analgesia in the short term, but at the cost of additional adverse effects. The lowest effective dose was 225–300 mg/day.

Cardiovascular effects of moderate normovolaemic haemodilution during enflurane–nitrous oxide anaesthesia in man

The cardiovascular effects of mild normovolaemic haemodilution during enflurane–nitrous oxide anaesthesia were studied in 20 patients with normal cardiac function before, during and after total hip replacement. After induction of anaesthesia, patients were randomly allocated to one control group (C), or one haemodiluted group (H) where Hct was decreased to 30% by replacement of blood volume by an identical volume of hydroxyethyl starch 200/0.5. Each patient was monitored with a pulmonary artery catheter allowing the measurement of right ventricular ejection fraction. During haemodilution, stroke index and right ventricular end–diastolic volume index increased from 33.1 7.9 to 39.3 7.1 ml M‐2 and from 73.8 20.3 to 94.9 18.5 mlM‐2 respectively (mean s.d., both P<0.05). However, heart rate decreased so that cardiac index did not change. O2 delivery decreased significantly (from 389 70 to 31163 ml–min‐1 –m‐2; P<0.05), but was not different to the control group. O2 consumption was maintained by an increase in O2 extraction. During the surgical procedure, cardiac index was higher in the haemodiluted group than in the control group, so that O2 delivery was similar in the two groups. O2 consumption tended to be greater in the haemodiluted group.

Efficacy of adding clonidine to intrathecal morphine in acute postoperative pain: meta-analysis

BACKGROUND Clonidine may be used along with intrathecal morphine for single-dose postoperative analgesia in adults. The efficacy of this is not clear. METHODS A meta-analysis was performed for two endpoints of efficacy: the time to first postoperative analgesia request and the amount of systemic morphine used during the first 24 h after operation. A Bayesian inference supporting direct statements about the probability of the magnitude of an effect was also used. The frequency of the five adverse events (postoperative nausea or vomiting, sedation, respiratory depression, pruritus, and hypotension) was analysed. RESULTS Clonidine increased the duration of analgesia by 1.63 h [95% confidence interval (CI): 0.93-2.33]. There is a 90% probability that clonidine increases the duration of postoperative analgesia by more than 75 min compared with morphine alone. Clonidine reduced the amount of postoperative morphine by a mean of 4.45 mg (95% CI: 1.40-7.49 mg). There is a probability of 90% to obtain a decrease >2.3 mg but only 35% to obtain a decrease >5 mg. The incidence of hypotension was the only adverse event increased by clonidine (odds ratio 1.78; 95% CI: 1.02-3.12). CONCLUSIONS The addition of clonidine to intrathecal morphine extends the time to first analgesia and decreases the amount of morphine used. However, as the effects are small, and the results heavily influenced by a study in which intrathecal fentanyl was also given, this must be balanced with the increased frequency of hypotension.

Intravenous nicardipine in the treatment of postoperative arterial hypertension

BACKGROUND Calcium entry blockers are commonly used in the management of postoperative hypertension. The hemodynamic and blood gas effects of nicardipine, a dihydropyridine derivative available intravenously, were studied in patients after abdominal aortic surgery. METHODS Sixteen patients (66 +/- 8 years) who developed arterial hypertension (mean arterial pressure, > 90 mmHg) after abdominal aortic aneurysm reconstruction were studied. Fourteen patients had already been treated with a sodium nitroprusside infusion, the doses of which were maintained constant (mean dose: 1.42 +/- 1.04 micrograms/kg/min). Hemodynamic and blood gas data were collected at baseline, 15 minutes, and 45 minutes after a slow bolus administration of 3 to 5 mg of nicardipine. RESULTS After the nicardipine administration, mean arterial pressure decreased from 101 +/- 11 to 83 +/- 11 mmHg (p < 0.001), and the cardiac index acutely increased from 3.96 +/- 0.74 to 4.57 +/- 0.83 L/min/m2 (p < 0.05). Systemic vascular resistance significantly decreased. There were no significant changes in heart rate, stroke volume, cardiac filling pressures, pulmonary artery pressures, pulmonary vascular resistance, left ventricular stroke work, or right ventricular stroke work. One patient developed acute pulmonary edema, associated with a dramatic increase in cardiac filling pressures, and electrocardiographic signs of myocardial ischemia. Nicardipine administration was also associated with an acute reduction in Pao2 from 85.0 +/- 12.1 mmHg to 70.3 +/- 9.2 mmHg (p < 0.001), associated with an increase in venous admixture from 21.7% +/- 3.2% to 28.0% +/- 5.2% (p < 0.01). Oxygen delivery increased moderately and oxygen extraction decreased, but oxygen consumption was unchanged. CONCLUSION This study confirms the excellent efficacy of nicardipine in the management of postoperative hypertension, but underlines the risk of poor cardiac tolerance in patients after major surgery. Although oxygen delivery to the cells is usually well preserved, nicardipine can also significantly after blood oxygenation by increasing ventilation/perfusion mismatch.

Does ultrasound guidance improve the efficacy of dorsal penile nerve block in children

Background:  Penile nerve block (PNB) is a well‐established technique used for circumcision; it requires the injection of local anesthetics close to the dorsal nerve of the penis. The goal of this study was to compare the efficacy of ultrasound‐guided PNB versus the classical landmark‐based technique (LBT) in children undergoing circumcision.

Effect of Preoperative Single-Dose Corticosteroid Administration on Postoperative Morbidity Following Esophagectomy

BackgroundEight clinical trials involving the administration of preoperative i.v. methylprednisolone have been undertaken in order to decrease the considerable inflammatory response to esophageal resection, in an effort to decrease the supposedly associated morbidity and mortalityMethodA meta-analysis was performed for eight clinical end-points. Due to quality problems in seven of the eight included studies, a Bayesian meta-analysis using a skeptical prior derived from the results of the classical analysis was also performed.ResultsThe end-points including any organ dysfunction (OR = 0.30), respiratory complication (OR = 0.41), sepsis (OR = 0.37), liver dysfunction (OR = 18), cardiovascular dysfunction (OR = 0.28), and surgical anastomotic leak (OR = 0.42) were significantly decreased by methylprednisolone pretreatment. Following the Bayesian analysis, despite the use of skeptical priors, there is a 95% probability to obtain a relative risk reduction of at least 23% to 54%, depending of the end-point, by methylprednisolone pretreatment.ConclusionWe are in the presence of a potential benefit that cannot be accepted at face value due to the quality problems of the included studies. But in the presence of a remaining potential benefit after a Bayesian analysis starting from a skeptical prior, the best option would be the planning of a large multicenter prospective randomized study.

Intranasal sufentanil is effective for postoperative analgesia in adults.

PurposesThe aim of this prospective, randomized, doubleblind study was to compare two doses of intranasal sufentanil for postoperative analgesia, titrated according to individual requirements based upon a numeric rating scale (NRS) from 0 to 10 for pain.MethodsForty patients, American Society of Anesthesiologists physical status I-II, scheduled for herniorrhaphy or hemorrhoidectomy under general anesthesia, were included when postoperative NRS was > 3. Nurses used a nasal puff device delivering a constant volume. Patients were randomized into two groups: Group A patients received a dose of 0.025 µg·kg-1 /puff, Group B patients a dose of 0.05 µg·kg-1 /puff. Puffs were administered as often as needed to obtain NRS ≤ 3, with an interval time of five minutes. Hemodynamic, respiratory measures and sedation were recorded every five minutes.ResultsThe probability of persistence of pain in Group B was consistently lower than in Group A. After 20 min, 20% of the patients had a NRS score > 3 in Group B, as opposed to 60% in Group A. At 60 min, no patient had a NRS > 3 in Group B, whereas there was a probability of 20% to record a NRS > 3 for Group A. Hemodynamic, respiratory parameters and sedation remained stable with no intergroup differences.ConclusionsNasal administration of 0.050 µg·kg-1 /puff sufentanil allowed a NRS < 4 to be attained within one hour in all patients, with efficacy achieved after 20 min. These findings suggest that the intranasal route is an effective mode of sufen-tanil administration for immediate postoperative analgesia in adult patients.RésuméObjectifNotre étude prospective, randomisée et à double insu visait à comparer deux doses intranasales de sufentanil comme analgésie postopératoire, ajustées selon les besoins individuels calculés au moyen ďune échelle ďévaluation numérique (EEN) de la douleur de 0 à 10.MéthodeQuarante patients, ďétat physique ASA I-II, devant subir une herniorraphie ou une hémorroidectomie sous anesthésie générale, ont été inclus quand ľEEN était > 3. Les infirmires ont utilisé un instrument nasal à jet fournissant un volume constant. Les patients ont été répartis en deux groupes: ceux du groupe A ont re÷u une dose de 0,025 µg·kg-1/jet et ceux du groupe B, 0,05 µg·kg-1/jet. Le médicament a été administré aussi souvent que nécessaire pour obtenir une EEN ≤ 3, selon un intervalle de cinq minutes. Les mesures hémodynamiques et respiratoires et la sédation ont été notées toutes les cinq minutes.RésultatsLa probabilité ďune douleur persistante chez les patients du groupe B a été constamment plus basse que chez ceux du groupe A. Aprs 20 min, 20 % avaient un score ďEEN > 3 dans le groupe B, mais 60 % dans le groupe A. A 60 min, aucun patient n’avait une EEN > 3 dans le groupe B, mais il y avait une probabilité de 20 % ďun score ďEEN > 3 dans le groupe A. Les paramètres hémodynamiques et respiratoires et la sédation sont demeurés stables sans différence intergroupe.ConclusionĽadministration nasale de 0,050 µg·kg-1/jet de sufentanil a permis qu’une EEN < 4 soit obtenue en moins ďune heure chez tous les patients et ľefficacité atteinte après 20 min. On peut penser que ľadministration intranasale de sufentanil est un mode efficace pour ľanalgésie postopératoire immédiate chez des adultes.

Bayesian enhanced meta-analysis of post-operative analgesic efficacy of additives for caudal analgesia in children.

The authors calculated the effect size for post‐operative analgesia of three additives, clonidine, neostigmine, and tramadol to bupivacaine, ropivacaine, or levobupivacaine used for single‐dose caudal extradural blockade in children.