Prevention of atelectasis formation during the induction of general anesthesia in morbidly obese patients

Résumé: La formation des atélectasies durant l'induction de l'anesthésie générale est plus importante chez le patient obèse morbide. Nous avons démontré dans des travaux de recherche antérieurs que l'utilisation de la PEEP (Pression Positive en Fin d'Expiration) durant l'induction de l'anesthésie prévient la formation d'atélectasies chez des patients non obèses. Par conséquent, nous voulions étudier l'efficacité de la pression positive en fin d'expiration chez le patient obèse morbide dans la prévention de la formation d'atélectasies. Nous avons fait une étude de 23 patients obèses morbides (BMI > 35 kg / m2) dans 2 groupes. Dans le groupe utilisant la pression positive en fin d'expiration, les patients respiraient 100% d'oxygène pendant 5 minutes par l'intermédiaire d'un masque facial type CPAP avec une pression de 10 cm H20. Après l'induction de l'anesthésie, nous avons ventilé les patients au masque facial avec une PEEP de 10 cm H20. Dans le groupe de contrôle, nous avons procédé au même type d'induction sans utiliser la pression positive en fin d'expiration. La surface de poumon atélectatique a été évaluée par tomographie (CT scann). L'étude des échanges gazeux se faisait à 2 reprises, à partir de gazométries réalisées juste avant l'induction de l'anesthésie puis juste après l'intubation. Après l'induction de l'anesthésie et l'intubation, les patients du groupe de contrôle présentaient une quantité d'atélectasies plus importante que les patients du groupe où la PEEP avait été utilisée (10.4% + 4.8% dans le groupe de contrôle versus 1.3% dans le groupe utilisant la pression positive en fin d'expiration p < 0.001). Après l'intubation, en présence d'une fraction inspirée en oxygène à 100%, la Pa02 était significativement supérieure dans le groupe ayant utilisé la pression positive en fin d'expiration en comparaison avec le groupe de contrôle (respectivement 457 ± 130 mmHg versus 315 ± 100 mmHg). Nous avons conclu que chez le patient obèse morbide, le recours à la pression positive en fin d'expiration lors de l'induction de l'anesthésie permet de prévenir largement la formation d'atélectasies et s'accompagne d'une meilleure oxygénation. Abstract: Atelectasis caused by general anesthesia is increased in morbidly obese patients. We have shown that application of positive end-expiratory pressure (PEEP) during the induction of anesthesia prevents atelectasis formation in nonobese patients. We therefore studied the efficacy of PEEP in morbidly obese patients to prevent atelectasis. Twenty-three adult morbidly obese patients (b ody mass index >35 kg/m2) were randomly assigned to one of two groups. In the PEEP group, patients breathed 100% oxygen (5 min) with a continuous positive airway pressure of 10 cm H20 and, after the induction, mechanical ventilation via a face mask with a PEEP of 10 cm H2O. In the control group, the same induction was applied but without continuous positive airway pressure or PEEP. Atelectasis, determined by computed tomography, and blood gas analysis were measured twice: before the induction and directly after intubation. After endotracheal intubation, patients of the control group showed an increase in the amount of atelectasis, which was much larger than in the PEEP group (10.4% -± 4.8% in control group versus 1.7% ± 1.3% in PEEP group; P <0.001). After in.tubation with a fraction of inspired oxygen of 1.0, Pao, was significantly higher in the PEEP group compared with the control group (457 ±- 130 mm Hg versus 315 ± 100 mm Hg, respectively; P = 0.035) We conclude that in morbidly obese patients, atelectasis formation is largely prevented by PEEP applied during the anesthetic induction and is associated with a better oxygenation.

Monitoring of sedation during neuroaxial blockade.

Abstract Study objective: The arousal state changes during spinal anesthesia. It is not clear if BIS and others devices could monitor the induced neuroaxial blockade sedation. Our objective was evaluate BIS and entropy values when spinal anesthesia is done. Design: We developed a prospective study. Patients: 40 patients were included in this study, ASA I-III, over 60 years old, undergoing spinal anesthesia, without premedication scheduled for orthopedics procedures. Intervention: Spinal anesthesia was performed with the unseated volunteer in the lateral decubitus position with a 25-gauge Whitacre needle at L2-L3 space, andanesthesia was done with 12 mg of 0.5% hyperbaric bupivacaine. Patients were positioned supine for 5 min after spinal anesthesia. Measurements: Observer’s Assessment of Alertness/Sedation OAA/S, response (RE) and state entropy (SE) and BIS, and standard hemodynamic measures. Main results: Statistical analysis were performed by Wilcoxon test or ANOVA, p<0.05 was considered statistically significant.RE and BIS showed a better correlation with the OAA/S scale values (Pk 0.81 and 0.82) than SE (Pk 0.69). The OAA/S, RE and SE showed significative differences from basal values after 30 min of neuroaxial anesthesia (ANOVA p<0.05). BIS showed differences after 40 min (ANOVA p<0.05). There were no differences between BIS and RE values along the study (ANOVA p>0.05). Conclusions: The spinal anesthesia decreased the cortical activity and these were founded by OAA/S scale and depth anesthetics monitors. OAA/S was a more sensitive value of this induced sedation. BIS and RE showed a better correlation with OAA/S scale than SE.

Comodidad materna y reducción del dolor en mujeres con posición fetal occipitoposterior durante el parto con el uso de las posturas de decúbito lateral y manos-rodillas: Ensayo clínico aleatorizado

Objective: To assess the maternal comfort and reduction of pain associated with contractions during labor with “hands-knees” (HK) maternal posture compared with “lateral maternal postures toward the fetal back” in pregnant women with occipitoposterior (OP) fetal position. Methods: In the multicenter trial by randomization, 70 women with OP fetal position during labor took the lateral posture and 65 women the HK posture for at least 30 minutes. We analyzed maternal comfort, perceived pain, influence of epidural analgesia and use of fit-ball on posture HK. Results: Back pain and abdominal pain reduction was higher with HK posture. With lateral posture 78.6% of women expressed comfort versus 73.8% of women with HK posture. Regarding the lateral posture, the comfort with HK posture reduces in multiparous women, with an odds ratio (OR) of 0.29, for a confidence interval (CI) 95% 0.12 to 0.76, and epidural analgesia (OR= 0.39; CI 95%: 0.15-1.03), comfort with K posture is higher with reduction of pain (OR= 4.13, 95% CI: 1.34- 12.72) and abdominal pain compared with back pain (OR= 4.05, 95% CI: 1.36-11.85). Conclusions: Women consider comfortable lateral and HK maternal postures during labor. The lateral posture is most comfortable for multiparous and epidural analgesia. The reduction of pain during labor is higher with HK posture, recommending this posture in primiparous women without epidural analgesia.

Postoperative epidural hematoma contributes to delayed upper cord tethering after decompression of Chiari malformation type I.

Symptomatic arachnoiditis after posterior fossa surgical procedures such as decompression of Chiari malformation is a possible complication. Clinical presentation is generally insidious and delayed by months or years. It causes disturbances in the normal flow of cerebrospinal fluid and enlargement of a syrinx cavity in the upper spinal cord. Surgical de-tethering has favorable results with progressive collapse of the syrinx and relief of the associated symptoms. Case Description: A 30-year-old male with Chiari malformation type I was treated by performing posterior fossa bone decompression, dura opening and closure with a suturable bovine pericardium dural graft. Postoperative period was uneventful until the fifth day in which the patient suffered intense headache and progressive loose of consciousness caused by an acute posterior fossa epidural hematoma. It was quickly removed with complete clinical recovering. One year later, the patient experienced progressive worsened of his symptoms. Upper spinal cord tethering was diagnosed and a new surgery for debridement was required. Conclusions: The epidural hematoma compressing the dural graft against the neural structures contributes to the upper spinal cord tethering and represents a nondescribed cause of postoperative fibrosis, adhesion formation, and subsequent recurrent hindbrain compression.

Deep thiopental anesthesia alters steady-state glucose homeostasis but not the neurochemical profile of rat cortex.

Barbiturates are regularly used as an anesthetic for animal experimentation and clinical procedures and are frequently provided with solubilizing compounds, such as ethanol and propylene glycol, which have been reported to affect brain function and, in the case of (1)H NMR experiments, originate undesired resonances in spectra affecting the quantification. As an alternative, thiopental can be administrated without any solubilizing agents. The aim of the study was to investigate the effect of deep thiopental anesthesia on the neurochemical profile consisting of 19 metabolites and on glucose transport kinetics in vivo in rat cortex compared with alpha-chloralose using localized (1)H NMR spectroscopy. Thiopental was devoid of effects on the neurochemical profile, except for the elevated glucose at a given plasma glucose level resulting from thiopental-induced depression of glucose consumption at isoelectrical condition. Over the entire range of plasma glucose levels, steady-state glucose concentrations were increased on average by 48% +/- 8%, implying that an effect of deep thiopental anesthesia on the transport rate relative to cerebral glucose consumption ratio was increased by 47% +/- 8% compared with light alpha-chloralose-anesthetized rats. We conclude that the thiopental-induced isoelectrical condition in rat cortex significantly affected glucose contents by depressing brain metabolism, which remained substantial at isoelectricity.

Patients's satisfaction concerning postoperative analgesia after caesarean section: a comparison of 4 alternative analgesic regimen

Introduction: Different routes of postoperative analgesia may be used after cesarean section: systemic, spinal or epidural [1]. Although the efficacy of these alternative analgesic regimen has already been studied [2, 3], very few studies have compared patients' satisfaction between them. Methodology: After ethical committee acceptation, 100 ASA 1 patients scheduled for an elective cesarean section were randomized in 4 groups. After a standardized spinal anesthesia (hyperbaric bupivacaine 10 mg and fentanyl 20 μg), each group had a different postoperative analgesic regimen: - Group 1: oral paracetamol 4x1 g/24 h, oral ibuprofene 3x600 mg/24 h and subcutaneous morphine on need (0.1 mg/kg 6x/24 h) - Group 2: intrathecal morphine (100 μg) and then same as Group 1 - Group 3: oral paracetamol 4x1 g/24 h, oral ibuprofene 3x600 mg/24 h and PCEA with fentanyl 5 μg/ml epidural solution - Group 4: oral paracetamol 4x1g/24 h, oral ibuprofene 3x600 mg/ 24 h and PCEA with bupivacaine 0.1% and fentanyl 2 μg/ml epidural solution After 48 hours, a specific satisfaction questionnaire was given to all patients which permitted to obtain 2 different scores concerning postoperative analgesia: a global satisfaction score (0-10) and a detailed satisfaction score (5 questions scored 0-10 with a summative score of 0-50). Both scores, expressed as mean ± SD, were compared between the 4 groups with a Kruskall-Wallis test and between each group with a Mann-Whitney test. A P-value <0.05 was considered significant. Results: Satisfaction scores Gr. 1 (n = 25) Gr. 2 (n = 25) Gr. 3 (n = 25) Gr. 4 (n = 25) P-value global (0-10) 8.2 ± 1.2 9.0 ± 1.0 7.8 ± 2.1 6.5 ± 2.5 0.0006 detailed (0-50) 40 ± 6 43 ± 5 38 ± 6 34 ± 8 0.0002 Conclusion: Satisfaction scores were significantly better in patients who received a systemic postoperative analgesia only (Groups 1 and 2) compared to patients who received systemic and epidural postoperative analgesia (Groups 3 and 4). The best scores were achieved with the combination of intrathecal morphine and multimodal systemic analgesia (Group 2) which allowed early ambulation without significant pain. Patients treated with postoperative epidural analgesia with combined local anesthetics and opioids (Group 4) obtained the worse scores (more restrictive nursing with less mobility, frequent asymmetrical block with insufficient analgesia on one side and motor block on the other)

Effect of an I.V. bolus of phenylephrine or ephedrine on skin blood flow during spinal anesthesia

Effet d'un bolus intraveineux de phénylephrine ou d'éphedríne sur le flux sanguin cutané lors d'une anesthésie rachidienne Introduction : La phénylephrine et l'éphedrine sont des substances vaso-actives utilisées de routine pour corriger des épisodes d'hypotension artérielle induits par l'anesthésie intrarachidienne. L'influence de ces deux vasopresseurs sur le flux sanguin cutané (FSC) dans ce contexte n'a jusqu'à maintenant pas été décrite. Cette étude évalue l'effet d'une injection intraveineuse de 75 µg de phénylephrine ou de 7.5 mg d'éphedrine sur le FSC mesuré par Laser Doppler, dans les zones concernées parle bloc sympathiqué induit par l'anesthésie intrarachidienne (membres inférieurs) et dans les zones non concernées (membres supérieurs). Méthode :Après acceptation par le Comité d'Éthique, et obtention de leur accord écrit, 20 patients devant subir une intervention chirurgicale élective en décubitus dorsal sous anesthésie. intrarachidienne ont été inclus dans cette étude randomisée en double insu. Le FSC a été mesuré en continu par deux sondes fixées l'une à la cuisse (zone avec bloc sympathique) et l'autre sur l'avantbras (zone sans bloc sympathique). Les valeurs de FSC ont été enregistrées après l'anesthésie rachidienne (valeur contrôle), puis après l'injection i.v. dè phénylephrine (10 patients) ou d'éphedrine (10 patients) pour corriger une hypotension définie comme une chute de 20 mmHg de la pression artérielle systolique. Les variations de FSC exprimées en pourcentage de la valeur contrôle moyenne (+/- écart type) ont été analysées par le test t de Student. Résultats :Les données démographiques des patients et le niveau sensitif induit par l'anesthésie rachidienne sont similaires dans les deux groupes. Aux doses utilisées, seule l'éphedrine restaure la pression artérielle aux valeurs précédant l'anesthésie rachidienne. La phénylephrine augmente le FSC de l'avant-bras de 44% (+/- 79%) et de la cuisse de 34% (+/-24%), alors que l'éphedrine diminue le débit sanguin cutané de l'avant-bras de 16% (+/- 15%) et de la cuisse de 22% (+/-11%). Conclusion : L'injection intraveineuse de phénylephrine et d'éphedrine ont des effets opposés sur le flux sanguin cutané, et cette réponse n'est pas modifiée par le bloc sympathique.. Cette différence peut s'expliquer par la distribution des sous-types de récepteurs adrénergiques alpha et leur prédominance relative dans les veines et les artères de différents diamètres perfusant le tissu sous-cutané et la peau. L'éphedrine, èn raison de sa meilleure efficacité pour traiter les épisodes d'hypotension artérielle après anesthésie intrarachidienne devrait être préféré à la phénylephrine, leurs effets opposés sur le flux sanguin cutané n'étant pas pertinents en pratique clinique. SUMMARY Background: Phenylephrine or ephedrine is routinely used to correct hypotensive episodes fallowing spinal anaesthesia (SA). The influence of these two vasopressors on skin blood flow (SBF) has not yet been described. We have therefore evaluated the effects of an i.v. bolus of 75 µg phenylephrine or 7.5 mg of ephedrine on SBF measured by laser Doppler flowmetry during sympathetic blockade induced by SA. Methods: With Ethical Committee approval and written consent, 20 patients scheduled for elective procedures in supine position under SA were enrolled in this double-blind randomized study. SBF was measured continuously by two probes fixed at the thigh (area with sympathic blockade) and forearm level (area without sympathic blockade) respectively. SBF values were recorded after SA (control values) and then after a bolus administration of phenylephriné (n=10) or ephedrine (n=10) when systolic blood pressure decreased by 20 mmHg. Changes were expressed as percentage of control SBF values and analysed by Student's paired t-test. Results: Patient characteristics and dermatomal sensory levels were similar in both groups. Phenylephrine increases mean SBF at the forearm level by 44% (79%) [mean (SD)j and at the thigh by 34% (24%). Ephedrine decreases SBF at the forearm level by 16% (15%) and at the thigh by 22% (il%). Ephedrine bolus restores arterial blood pressure to pre-anaesthesia values, whereas phenylephrine does not. Conclusion: Administratión of phenylephrine and ephedrine has opposite effects on skin blood flow and sympathetic blockade does not modify this response. These findings could be explained by the distribution of the alpha-adrenoréceptor subtypes and their relative predominance among veins and arteries of different size perfusing the subcutaneous tissue and the skin. Ephedrine, due to its better efficacy to correct hypotensive episodes following SA, should be preferred, to phenylephrine, their opposite effects on SBF being not relevant for clinical practice.

Propofol anesthesia impairs the maturation and survival of adult-born hippocampal neurons.

BACKGROUND: Adult neurogenesis occurs in the hippocampus of most mammals, including humans, and plays an important role in hippocampal-dependent learning. This process is highly regulated by neuronal activity and might therefore be vulnerable to anesthesia. In this article, the authors investigated this possibility by evaluating the impact of propofol anesthesia on mouse hippocampal neurons generated during adulthood, at two functionally distinct maturational stages of their development. METHODS: Adult-born hippocampal neurons were identified using the cell proliferation marker bromodeoxyuridine or a retroviral vector expressing the green fluorescent protein in dividing cells and their progenies. Eleven or 17 days after the labeling procedure, animals (n = 3-5 animals per group) underwent a 6-h-long propofol anesthesia. Twenty-one days after labeling, the authors analyzed the survival, differentiation, and morphologic maturation of adult-born neurons using confocal microscopy. RESULTS: Propofol impaired the survival and maturation of adult-born neurons in an age-dependent manner. Anesthesia induced a significant decrease in the survival of neurons that were 17 days old at the time of anesthesia, but not of neurons that were 11 days old. Similarly, propofol anesthesia significantly reduced the dendritic maturation of neurons generated 17 days before anesthesia, without interfering with the maturation of neurons generated 11 days before anesthesia. CONCLUSIONS: These results reveal that propofol impairs the survival and maturation of adult-born hippocampal neurons in a developmental stage-dependent manner in mice.

Efecto de la hidratación endovenosa con Hidroxietil almidón 6% (Voluven®) versus Ringer Lactato previa a la analgesia epidural en la incidencia de hipotensión durante el trabajo de parto

En pacientes gestantes durante trabajo de parto, la fluidoterapia endovenosa es fundamental en la prevención de la hipotensión tras la analgesia epidural y mantener el bienestar materno-fetal. El tipo de fluidoterapia administrada (coloides o cristaloides) puede influir en la incidencia y grado de dicha hipotensión. El objetivo de nuestro estudio fue evaluar la incidencia de hipotensión tras la administración de un coloide (Hidroxietil almidón 6%, 250 ml) o un cristaloide (Ringer Lactato 750 ml), evaluando también la posible repercusión fetal. Hasta la fecha hemos incluido 60 gestantes, mostrando una tendencia a una mejor hemodinámica en el grupo coloides

Nontraumatic spinal epidural hematoma during pregnancy: diagnosis and management concerns.

OBJECTIVE: Nontraumatic spinal epidural hematoma (SEH) during pregnancy is rare. Therefore, appropriate management of this occurrence is not well defined. The aim of this study was to extensively review the literature on this subject, to propose some novel treatment guidelines. METHODS: Electronic databases, manual reviews and conference proceedings up to December 2011 were systematically reviewed. Articles were deemed eligible for inclusion in this study if they dealt with nontraumatic SEH during pregnancy. Search protocols and data were independently assessed by two authors. RESULTS: In all, 23 case reports were found to be appropriate for review. The mean patient age was 28 years and gestational age was 33.2 weeks. Thirteen cases presented with acute interscapular pain. The clinical picture consisted of paraplegia, which occurred approximately 63 h after pain onset. Spinal cord decompression was performed within an average time of 20 h after neurological deficit onset. Fifteen patients had cesarean deliveries, even when the gestational age was less than 36 weeks. CONCLUSION: This review failed to identify articles, other than case reports, which could assist in the formation of new guidelines to treat SEH in pregnancy. However, we believe that SEH may be managed neurosurgically, without requiring prior, premature, cesarean section.

Deep thiopental anesthesia alters steady-state glucose homeostasis but not the neurochemical profile of rat cortex.

Barbiturates are regularly used as an anesthetic for animal experimentation and clinical procedures and are frequently provided with solubilizing compounds, such as ethanol and propylene glycol, which have been reported to affect brain function and, in the case of (1)H NMR experiments, originate undesired resonances in spectra affecting the quantification. As an alternative, thiopental can be administrated without any solubilizing agents. The aim of the study was to investigate the effect of deep thiopental anesthesia on the neurochemical profile consisting of 19 metabolites and on glucose transport kinetics in vivo in rat cortex compared with alpha-chloralose using localized (1)H NMR spectroscopy. Thiopental was devoid of effects on the neurochemical profile, except for the elevated glucose at a given plasma glucose level resulting from thiopental-induced depression of glucose consumption at isoelectrical condition. Over the entire range of plasma glucose levels, steady-state glucose concentrations were increased on average by 48% +/- 8%, implying that an effect of deep thiopental anesthesia on the transport rate relative to cerebral glucose consumption ratio was increased by 47% +/- 8% compared with light alpha-chloralose-anesthetized rats. We conclude that the thiopental-induced isoelectrical condition in rat cortex significantly affected glucose contents by depressing brain metabolism, which remained substantial at isoelectricity.

Syndrome d'apnées du sommeil: un risque pour l'anesthésie générale [Obstructive sleep apnea: a risk for general anesthesia?]

There are many case reports of serious complications and death among obstructive sleep apnea patients (OSA) during general anesthesia or postoperative analgesia. Sedatives and anesthetic agents, pharyngeal anatomy of these patients, opiates given for analgesia, and post operative REM sleep rebound represent potential hazards for general anesthesia in OSA patients. Ideally these patients should be treated with continuous positive airway pressure (CPAP) during premedication, directly after extubation and during postoperative analgesia. Unfortunately, only about 20% of these patients are diagnosed before surgery. A special attention should be given to the symptoms and signs suggestive of OSA during preoperative visits. Screening tests should be performed in patients with suspected OSA and, if positive, a treatment should be initiated.