Jean G. Boogaerts

Difference in risk factors for postoperative nausea and vomiting.

Background It is commonly stated that risk factors for postoperative nausea are the same as for vomiting. The authors designed a prospective study to identify and differentiate the risk factors for postoperative nausea and vomiting in various surgical populations in a clinical audit setting. Methods The study included 671 consecutive surgical inpatients, aged 15 yr or more, undergoing various procedures. The study focused on postoperative nausea visual analog scale scores every 4 h and vomiting episodes within 72 h. Both vomiting and retching were considered as emetic events. Patient-, anesthesia-, and surgery-related variables that were considered to have a possible effect on the proportion of patients experiencing postoperative nausea and/or vomiting were examined. The bivariate Dale model for binary correlated outcomes was used to identify selectively the potential risk factors of postoperative nausea and vomiting. Results Among the 671 patients in the study, 126 (19%) reported one or more episodes of nausea, and 66 patients (10%) suffered one or more emetic episodes during the studied period. There was a highly significant association between the two outcomes. Some risk factors were predictive of both nausea and vomiting (female gender, nonsmoking status, and general anesthesia). History of migraine and type of surgery were mainly responsible for nausea but not for vomiting. The predictive effect of risk factors was controlled for postoperative pain and analgesic drugs. Conclusion This study shows that differences exist in risk factors of postoperative nausea and vomiting. These could be explained by differences in the physiopathology of the two symptoms.

Epidural administration of liposome associated bupivacaine for the management of postsurgical pain: A first study

STUDY OBJECTIVES To explore the influence of liposomes on the pharmacodynamic action of bupivacaine and to determine whether postsurgical analgesic advantages can be obtained from epidural delivery of liposomal bupivacaine compared with the current formulation. DESIGN Open, nonrandomized study. SETTING Physiopathology laboratory, general operating theaters, and intensive care units of Reine Fabiola Hospital and Institut Médical de Traumatologie et Revalidation. PATIENTS 26 ASA physical status II and III patients who had undergone major surgery (abdominal, vascular, urologic, thoracic, orthopedic). INTERVENTIONS After completion of the operation, the patients were divided into 2 groups to receive 1 of 2 bupivacaine preparations epidurally for postsurgical pain: Group 1 (n = 12) received plain 0.5% bupivacaine with 1:200,000 epinephrine; Group 2 (n = 14) received liposomal 0.5% bupivacaine. MEASUREMENTS AND MAIN RESULTS The following observations were made: onset and quality of analgesia, quality of motor block according to the Bromage scale, and sympathetic block. Onset time of sensory block averaged 15 minutes in both groups. Pain relief durations were 3.2 +/- 0.4 hours with plain bupivacaine and 6.25 +/- 1.13 hours with the liposomal preparation (p < 0.05). In the liposomal bupivacaine group, no motor block was recorded. Low sympathetic block occurred in all patients. Analgesia in a subset of patients following abdominal aortic surgery increased from 2.4 +/- 0.35 hours to 10.6 +/- 1.4 hours by encapsulation of bupivacaine (p < 0.01). There was no neurotoxicity or cardiotoxicity. CONCLUSIONS The liposomal formulation of bupivacaine increased duration of analgesia without motor block or adverse side effects.

Toxicity of bupivacaine encapsulated into liposomes and injected intravenously: comparison with plain solutions.

The acute central nervous system and cardiac toxicities of 0.25% bupivacaine, without adrenalin, encapsulated in multilamellar liposomes were compared with 0.25% plain solutions with and without adrenalin after intravenous infusion at a rate of 0.15 mg.kg-1 x min-1 with an increase of 0.036 mg.kg-1 x min-1 every 10 min. Three groups of six anesthetized, unventilated rabbits were studied. The doses of bupivacaine (in mg.kg-1) which produced seizure, ventricular tachycardia, and asystole were determined. The doses of bupivacaine inducing seizure and ventricular tachycardia were significantly higher for liposomal bupivacaine than for the two plain solutions. A statistical comparison of the cumulative lethal doses of bupivacaine 0.25% with adrenalin and of liposomal bupivacaine led to a P = 0.06. Adrenalin did not modify the systemic toxicity of the local anesthetic. This study showed a reduction of nervous and cardiac toxicity of bupivacaine encapsulated in multilamellar liposomes when infused intravascularly.

Use of liposome-associated bupivacaine in a cancer pain syndrome.

Bupivacaine. 0.25% encapsulated by multilamellar liposomes was administered epidurally to a patient suffering pain associated with lung cancer and the effect compared with a plain bupivacaine solution of the same concentration. Complete analgesia was produced for 4 h with the plain solution and 11 h with the liposomal formulation. No motor blockade or haemodynamic instability was observed with the liposome‐associated bupivacaine.

Continuous Epidural Infusion of Large Concentration/Small Volume Versus Small Concentration/Large Volume of Levobupivacaine for Postoperative Analgesia

In this randomized study, we evaluated the quality of postoperative analgesia and the incidence of side effects of continuous thoracic epidural levobupivacaine 15 mg/h in 2 different concentrations: 0.5%, 3 mL/h (n = 33) or 0.15%, 10 mL/h (n = 27). The following variables were registered within 48 h: sensory block, pain scores, rescue morphine consumption, motor blockade, hemodynamics, sedation, nausea and vomiting, and patient satisfaction. The two groups were similar with regard to demographics, cephalad level of sensory block, quality of analgesia, morphine consumption, side effects, and high satisfaction rate. Motor blockade was weaker in the 0.5% group (P = 0.025), with a significantly increased hemodynamic stability, compared with the 0.15% group (P = 0.004). In conclusion, the same dose of levobupivacaine provides an equal quality of analgesia in small- or large-volume continuous epidural infusion and decreases the incidence of motor blockade and hemodynamic repercussions. This is in accordance with the assumption that the total dose of local anesthetics determines the spread and quality of analgesia.

Effectiveness of an acute pain service inception in a general hospital

STUDY OBJECTIVES To assess the effects of an Acute Pain Service (APS) inception on postoperative pain management in a general teaching hospital using pain indicators as performance measures. DESIGN Open, prospective, nonrandomized, observational study. SETTING Postanesthesia Care Unit, surgical wards of University Hospital Center of Charleroi. PATIENTS 1304 patients in the pre-APS inception phase and 671 patients after its implemention who have undergone various types of surgery (orthopedics, gynecology, urology, neurosurgery, stomatology, ear, nose, and throat, ophthalmic, abdominal, vascular-thoracic, plastic, and maxillofacial). INTERVENTIONS An APS, nurse-based, anesthesiologist-supervised model was devised, based on the concept that postoperative pain relief can be greatly improved by providing in-service training for surgical nursing staff and optimal use of systemic analgesics. MEASUREMENTS AND MAIN RESULTS Postoperative pain was assessed using a visual analog scale (VAS) every 4 hours for 72 hours in the two phases. Analgesic consumption was registered at the same time. Time-related VAS scores were summarized using several pain indicators. There was an overall improvement in the pain scores after APS inception. The differences were most pronounced, around 50%, in patients undergoing vascular, maxillofacial, gynecologic, and urologic surgeries, and stomatology. Regular administration of paracetamol and nonsteroidal antiinflammatory drugs decreased morphine consumption in the second phase. CONCLUSION This study validates the benefits of a formal APS, using continuous monitoring of rest pain intensity and analgesic consumption in the postoperative period. Results not only support previous research findings but also offer outcome-based tools to evaluate current practices as compared with desired outcomes.

Clinical features and echocardiography of embolism during cemented hip arthroplasty

PurposeIn previous studies the degree of embolization detected by transoesophageal echocardiography (TEE) dunng cemented total hip arthroplasty (THA) did not correlate with changes in haemodynamic variables nor did it result in persistent ventilation-perfusion mismatching. The aim of this study was to record evidence of embolism and to relate the findings to demographic data and the subsequent clinical course of the patients dunng THA.MethodForty-eight patients scheduled to undergo elective cemented THA dunng general anaesthesia were monitored. A TEE probe was inserted with special attention to the nght atnum (RA), the nght ventnele (RV). Haemodynamic (heart rate, arterial blood pressure, central venous pressure) and blood-gas vanables were measured repeatedly during the operative procedure (after induction, placement of the acetabular component, placement of the femoral component, relocation of the hip joint). Grading of venous embolism at these times was based on the size of particles detected by TEE (three-minutes video segments of each penods) and correlated with demographic, haemodynamic and blood-gas data.ResultsThe TEE monitoring revealed showers of echogenic matenal traversing the RA and RV in all but one patients dunng reaming and cementing of the acetabular and femoral components, and dunng relocation of the hip joint. No correlation was observed between frequency or size of embolic particles and demographic or blood-gas and haemodynamic vanables studied at the same times.ConclusionThis study failed to show any clinical impact of TEE detected emboli dunng cemented THA.RésuméObjectifDes études anténeures ont montré que le degré de l’embolisation décelé par échographie transoesophagienne (ETO) pendant l’arthroplastie totale de la hanche (ATH) cimentée ne corrélait pas avec les changements des paramètres hémodynamiques et ne provoquait pas d’inégalités persistantes du rapport ventilation-perfusion. Cette étude visait à enregistrer, au cours de l’ATH, l’appantion des embolies et de corréler ces données avec les données démographiques et l’évolution clinique subséquente des opérés.MéthodesQuarante-huit patients programmés pour subir une ATH cimentée non urgente étaient monrtorés sous anesthésie générale La sonde ETO était insérée en ciblant spécialement l’oreillette droite (OD) et le ventricule droit (VD). Les paramètres hémodynamiques (fréquence cardiaque, pression arténelle, tension veineuse centrale) et la gazométne étaient mesurés à intervalles fixes pendant l’intervention chirurgicale (après l’induction, pendant l’installation du segment acétabulaire, à l’installation du segment fémoral, et lors de la réduction de la dislocation de la hanche). Le degré d’embolisation veineuse était alors établi selon la grosseur des particules détectées par ETO (enregistrements vidéo de trois minutes pour chacune des périodes) et corrélé avec les données démographiques, hémodynamiques et gazométnques.RésultatsLe monitorage ETO a révélé que. chez tous les patients, une pluie de maténel échogène traversait l’OD et le VD pendant l’alésage et la cimentation des segments acétabulaire et fémoral et pendant la réduction de la dislocation de la hanche. ll n’y avait pas de corrélation entre la fréquence et la grosseur des particules emboliques et les paramètres démographiques, gazométnques et hémodynamiques enregistrés simultanément.ConclusionCette étude n’a pas montré que les embolies détectées par ETO pendant l’ATH cimentée avaient un impact clinique.

Plasma concentrations of bupivacaine after brachial plexus administration of liposome-associated and plain solutions to rabbits

Bupivacaine has been associated to multilamellar liposomes with the aim of altering circulating plasma concentrations after injection into the rabbit brachial plexus. Plasma concentrations of bupivacaine have been compared after administration of free drug (BP) or bupivacaine associated to multilamellar liposomes (BP-MLV) made of phosphatidylcholine and cholesterol (molar ratio 4:3). Under light general anaesthesia, one group of six rabbits received an axillary injection of 2.5 mg BP (1 ml, 0.25%), and a second received the same dose of BP-MLV. In both groups3H bupivacaine was used as a marker. The brachial plexus was located using a nerve stimulator. Injection of the anaesthetic solutions invariably prevented the motor response of the paw. The arterial plasma concentrations of bupivacaine were determined after 5 to 240 min and after 24 hr by beta counting. In the MLV population, additional measurements were performed after 48 and 72 hr. The two plasma curves showed a plateau (0.2 μg · ml−1) which was reached after five minutes in the BP group and after 90 min using BP-MLV In the BP-MLV group, the plasma concentrations of bupivacaine were lower during the first ten minutes (P < 0.05), and higher after 24 hr (P < 0.05). Radioactivity decreased between 4 and 24 hr in the BP group and between one and two days in the BP-MLV population. It is concluded that elevated plasma drug concentrations were maintained for longer with BP-MLV than with BP This could prolong the action of the local anaesthetic through a slow release.RésuméLa bupivacaïne a été associée à des liposomes multilamellaires, composés de phosphatidylcholine et cholestérol (rapport molaire 4:3) dans le but de modifier les concentrations plasmatiques de l’anesthésique local après administration au niveau du plexus brachial du lapin. Sous anesthésie générale, un premier groupe (BP) de six lapins a reçu une injection plexique de 1 ml de bupivacaïne commerciale à 0,25% sans adrénaline. Le second groupe (BP-MLV) a reçu 1 ml de bupivacaine liposomale à 0,25%. De la bupivacaine tritiée a été utilisée comme marqueur. Le plexus brachial a été repéré à l’aide d’un stimulateur de nerf. L’injection des solutions anesthésiques fit disparaître les réponses musculaires dans la patte. Les concentrations artérielles de bupivacaïne ont été mesurées à des temps différents (de 5 à 240 minutes et après 24 heures) par comptage de la radioactivité plasmatique et exprimées en μg · ml−1. Dans le groupe MLV, des prélèvements supplémentaires ont été pratiqués après 48 et 72 hr. Les deux courbes plasmatiques montrent un plateau identique (0,2 μg · ml−1), qui est atteint après cinq minutes dans le groupe BP et après 90 min dans le groupe BP-MLV Dans ce dernier groupe, la concentration plasmatique de bupivacaïne était plus basse durant les dix premières minutes (P < 0,05) et plus élevée après 24 hr (P < 0,05). La concentration plasmatique de bupivacaïne diminuait entre 4 et 24 hr dans le groupe BP et après un à deux jours dans le groupe BP-MLV. L’association de la bupivacaïne à des MLV pourrait prolonger la durée d’action de la bupivacaïne administrée au niveau du plexus brachial par le biais d’une libération progressive de l’anesthésique local.

Effect of Nutritional Status on Oxidative Stress in an Ex Vivo Perfused Rat Liver

Background: Normothermic ischemia-reperfusion is a determinant in liver injury occurring during surgical procedures, ischemic state, and multiple organ failure. The preexisting nutritional status of the liver might contribute to the extent of tissue injury and primary nonfunction. The aim of this study was to determine the role of starvation on hepatic ischemia-reperfusion injury in normal rat livers. Methods: Rats were randomly divided into two groups: one had free access to food, the other was fasted for 16 h. The portal vein was cannulated, and the liver was removed and perfused in a closed ex vivo system. Two modes of perfusion were applied in each series of rats, fed and fasting. In the ischemia-reperfusion mode, the experiment consisted of perfusion for 15 min, warm ischemia for 60 min, and reperfusion during 60 min. In the nonischemia mode, perfusion was maintained during the 135-min study period. Five rats were included in each experimental condition, yielding a total of 20 rats. Liver enzymes, potassium, glucose, lactate, free radicals, i.e., dienes and trienes, and cytochrome c were analyzed in perfusate samples. The proportion of glycogen in hepatocytes was determined in tissue biopsies. Results: Transaminases, lactate dehydrogenase, potassium, and free radical concentrations were systematically higher in fasting rats in both conditions, with and without ischemia. Cytochrome c was higher after reperfusion in the fasting rats. Glucose and lactate concentrations were greater in the fed group. The glycogen content decreased in both groups during the experiment but was markedly lower in the fasting rats. Conclusions: In fed rats, liver injury was moderate, whereas hepatocytes integrity was notably impaired both after continuous perfusion and warm ischemia in fasting animals. Reduced glycogen store in hepatocytes may explain reduced tolerance.

Embolism detected by transoesophageal echocardiography during hip arthroplasty

This case report demonstrates embolization of echogenic material detected by transoesophageal echocardiography during a cemented total hip arthroplasty in a 76- yr- old woman without patent foramen ovale. During the placement of the acetabular and femoral components, and during relocation of the hip joint, a “snow flurry” appearing in the right atrium was followed by several highly echogenic and mobile emboli of various sizes, some of them with a vermiform shape 1 to 5 cm long. At skin closure, echogenic material was seen in the right branch of the pulmonary artery adherent to the vascular wall of the bifurcation of the main pulmonary artery. No changes were observed in any haemodynamic variable monitored (heart rate, systemic and right atrial pressures). Also, no desaturation was detected by pulse oximetry and blood gases at the time of embolism and there was no decrease in PetCO2. This case report is in line with other studies which failed to show a haemodynamic impact of TEE detected emboli during THA.RésuméCe cas clinique démontre l’embolisation de matériel échogène détecté par échocardiographie transoesophagienne (ETO) à l’occasion de la mise en place d’une prothèse totale de hanche (PTH) cimentée chez une patiente de 76 ans sans foramen ovale perméable. Durant la mise en place des composants acétabulaire et fémoral, ainsi qu’à la réduction de la hanche, est apparue une image de « tempête de neige » dans l’oreillette droite suivie d’emboles vermiformes de taille variable pouvant atteindre 1 à 5 cm de long. Durant la fermeture, du materiel embolique a été mis en évidence au niveau de la bifurcation de l’artère pulmonaire, adhérant à la paroi vasculaire. Aucune répercus-sion hémodynamique (rythme cardiaque, pressions artérielle et veineuse centrale) a n’a été observée. De même, aucune désaturation détectée par oxymérie de pouls et gazométrie artérielle n’a été constatée. La PetCO2 est restée stable. Ce cas clinique, en accord avec d’autres études, souligne que l’impact hémodynamique des emboles détectés par ETO au cours de PTH cimentées est faible.