Yvan Pouzeratte

Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery.

Background Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient. Methods Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores. Results Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24%vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups. Conclusion After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.

The Effectiveness of Noninvasive Positive Pressure Ventilation to Enhance Preoxygenation in Morbidly Obese Patients: A Randomized Controlled Study

BACKGROUND: Noninvasive positive-pressure ventilation (NPPV) with pressure support-ventilation and positive end-expiratory pressure are effective in providing oxygenation during intubation in hypoxemic patients. We hypothesized administration of oxygen (O2) using NPPV would more rapidly increase the end-tidal O2 concentration (ETo2) than preoxygenation using spontaneous ventilation (SV) in morbidly obese patients. METHODS: Twenty-eight morbidly obese patients were enrolled in this prospective randomized study. Administration of O2 for 5 min was performed either with SV group or with NPPV (pressure support = 8 cm H2O, positive end-expiratory pressure = 6 cm H2O) (NPPV group). ETo2 was measured using the anesthesia breathing circuit, and is expressed as a fraction of atmospheric concentration. The primary end-point was the number of patients with an ETo2 >95% at the end of O2 administration. Secondary end-points included the time to reach the maximal ETo2 and the ETo2 at the conclusion of O2 administration. RESULTS: A larger proportion of patients achieved a 95% ETo2 at 5 min with NPPV than SV (13/14 vs 7/14, P = 0.01). The time to reach the maximal ETo2 was significantly less in the NPPV than in the SV group (185 ± 46 vs 222 ± 42 s, P = 0.02). The mean ETo2 at the conclusion of O2 administration was larger in the NPPV group than the SV group (96.9 ± 1.3 vs 94.1 ± 2.0%, P < 0.001). A modest, although significant, increase in gastric distension was observed in the NPPV group. No adverse effects were observed in either group. CONCLUSION: Administration of O2 via a facemask with NPPV in the operating room is safe, feasible, and efficient in morbidly obese patients. In this population NPPV provides a more rapid O2 administration, achieving a higher ETo2.

The relationship among carbon dioxide pneumoperitoneum, vasopressin release, and hemodynamic changes

UNLABELLED We assessed the role of vasopressin (VP) for the hemodynamic response to pneumoperitoneum in pigs. Four groups of anesthetized pigs were investigated. Nine pigs were intraabdominally insufflated with CO2 and eight were intraabdominally insufflated with argon; eight pigs received an i.v. injection of 1 mg/kg SR 49059, a VP antagonist, before CO2 insufflation; and six pigs received SR 49059 alone. Hemodynamics, plasma concentrations of VP and vasoactive hormones, and Paco2 were measured. Data were analyzed by using analysis of variance, Students t-test, and Mann-Whitney U-test. Five minutes after insufflation, changes in systemic vascular resistance (SVR) were significantly correlated with changes in VP (r = 0.72; P = 0.005) but not with changes in epinephrine, norepinephrine, renin activity, or Paco2. SVR increased during CO2 insufflation but not during argon insufflation or CO2 insufflation with a preceding infusion of SR 49059. The SR 49059 injection itself resulted in increases in heart rate and cardiac output and decreases in blood pressure and SVR. We conclude that, during CO2 pneumoperitoneum in pigs, absorbed CO2 initiates a pathophysiological process that stimulates VP release. Hence, VP most likely plays a key role in the hemodynamic response to a CO2-induced pneumoperitoneum. IMPLICATIONS Intraabdominal insufflation of CO2 is associated with hemodynamic and hormonal changes. Investigating CO2 and argon-insufflated pigs and using a vasopressin antagonist, we found that CO2 insufflation released vasopressin, which, in turn, induced hemodynamic perturbances.

Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study.

Background:During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. Methods:Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic “patient” inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high “patient” inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. Results:For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. Conclusion:Regarding trigger sensitivity and the system’s ability to meet inspiratory flow during pressure-supported breaths, the most recent anesthesia ventilators have comparable performances of recent-generation intensive care unit ventilators.

Posterior perineal block with ropivacaine 0.75% for pain control during and after hemorrhoidectomy

Background and Objectives As perioperative pain management is a difficult challenge during hemorrhoidectomy, we tested the hypothesis that posterior perineal block (PPB) with local anesthetics alone is able to provide adequate pain control during and after surgery. Methods In a prospective, blinded, randomized study, we studied analgesic conditions and side effects of PPB in American Society of Anesthesiologists (ASA) I-II patients undergoing hemorrhoidectomy. Patients received general anesthesia (GA) either with PPB (0.75% ropivacaine, 40 mL (PPB group) or without PPB (control group). All patients received intravenous morphine patient-controlled analgesia (PCA) for postoperative pain control (morphine, 1.5 mg-boluses, 8-minute lockout interval). Intra- and postoperative opioids consumption was recorded, and pain assessments were performed at 1, 2, 4, 8, 12, and 24 hours using a visual analog scale (VAS). Results VAS scores were significantly lower during the first 8 postoperative hours in the PPB group as compared with the control group (P < .001). The PPB group required significantly less opioids during anesthesia (P < .001) and during the first postoperative day (P < .001) as compared with the control group. Time to first defecation and duration of hospitalization were identical in both groups. Conclusions The present study shows that PPB with 40 mL 0.75% ropivacaine (300 mg) was a simple, effective, and safe method to provide better postoperative analgesia than PCA alone following surgical hemorrhoidectomy. In addition, PPB was shown to significantly reduce opioid consumption intraoperatively and during the first postoperative day.

Patient-controlled epidural analgesia after abdominal surgery: Ropivacaine versus bupivacaine

In this randomized, double-blinded study we sought to assess the analgesic efficacy of ropivacaine and bupivacaine in combination with sufentanil and the efficacy of ropivacaine alone after major abdominal surgery. Sixty patients undergoing major abdominal surgery received standardized general anesthesia combined with epidural thoracic analgesia. They were allocated to one of three groups: the BS group received postoperative patient-controlled epidural analgesia with 0.125% bupivacaine plus 0.5 &mgr;g/mL sufentanil; the RS group received 0.125% ropivacaine plus 0.5 &mgr;g/mL sufentanil; and the R group received 0.2% ropivacaine, with the patient-controlled epidural analgesia device set at bolus 2–3 mL and background infusion 3–5 mL/h. Visual analog scale scores were significantly lower during coughing in the BS group compared with the RS and R groups and in the RS group compared with the R group. The BS group required significantly less local anesthetic (milligrams per day) during the first three postoperative days compared with the RS and R groups, and the RS group, significantly less than the R group. No major side effects were noted in any group. We conclude that, after major abdominal surgery, thoracic epidural analgesia was more effective with bupivacaine than with ropivacaine when these two local anesthetics are used in a mixture with sufentanil. Ropivacaine alone was less effective than ropivacaine in combination with sufentanil.

Postoperative patient-controlled analgesia in the elderly: risks and benefits of epidural versus intravenous administration.

Postoperative patient-controlled analgesia provided by the intravenous route using morphine (PCA) or by the epidural route using an opioid in combination with a local anaesthetic (patient-controlled epidural analgesia; PCEA) is not yet routinely used in the elderly. However, this modality theoretically provides adequate control of postoperative pain in such patients.Firstly, an assessment of the level of pain is particularly difficult in the elderly, and patient-controlled techniques that enable the self-administration of analgesic could resolve this problem. Secondly, these techniques provide a fine and controlled titration of analgesic doses. Since analgesic-induced adverse effects increase with age, the risk of overdose is therefore reduced. Thirdly, effective postoperative patient-controlled analgesia may attenuate detrimental physiologic responses, and contribute to improvement in patient outcomes.In the elderly, PCEA provides better pain relief, particularly for dynamic pain, and improves postoperative recovery with a low incidence of adverse effects compared with PCA. PCA and PCEA techniques have a good safety profile in the elderly only when there is careful preoperative patient selection and strict postoperative monitoring. Standard observation of vital signs, sedation and pain scores and assessment of mental status are required. Patient selection is necessary to identify those patients who may be incapable of using the device (e.g. patients with evidence of cognitive dysfunction or physical disabilities). In addition, caution is required among patients with respiratory, renal or hepatic insufficiency.PCA and PCEA are particularly useful for elderly patients undergoing major thoraco-abdominal surgery. However, there is a need for further research in elderly patients. In the future, improvements in the management of postoperative pain in the elderly will lead to a greater expansion of self-controlled techniques.

Changes in occlusion pressure (P0.1) and breathing pattern during pressure support ventilation

BACKGROUND The purpose of this study was to investigate changes in breathing pattern, neuromuscular drive (P0.1), and activity of the sternocleidomastoid muscles (SCM) during a gradual reduction in pressure support ventilation (PSV) in patients being weaned off controlled mechanical ventilation. METHODS Eight non-COPD patients recovering from acute respiratory failure were included in this prospective interventional study. All patients were unable to tolerate discontinuation from mechanical ventilation. Each patient was evaluated during a period of spontaneous breathing and during PSV. Four successive levels of PSV were assessed in the following order: 20 cm H2O (PS20), 15 cm H2O (PS15), 10 cm H2O (PS10), and 5 cm H2O (PS5). RESULTS When pressure support was reduced from PS20 to PS10 the respiratory rate (f) and the rapid shallow breathing index (f/Vt) significantly increased and tidal volume (Vt) significantly decreased. These parameters did not vary when pressure support was reduced from PS10 to PS5. Conversely, P0.1 varied negligibly between PS20 and PS15 but increased significantly at low PSV levels. P0.1 values were always greater than 2.9 cm H2O (4.1 (1.1) cm H2O) when SCM activity was present. When contraction of the SCM muscles reappeared the P0.1 was the only parameter that changed significantly. CONCLUSIONS In postoperative septic patients the value of P0.1 seems to be more useful than breathing pattern parameters for setting the optimal level of pressure assistance during PSV.

The risk of cardiac injury during laparoscopic fundoplication: cardiac troponin I and ECG study Note

Background: Myocardial trauma has been described during gastroesophageal reflux laparoscopic surgery, in association with the proximity of cardiac structures. In addition, specific haemodynamic changes induced by CO2 pneumoperitoneum could exacerbate perioperative cardiac complication even in patients without cardiac risk factors. The aim of this study was to evaluate the influence of gastroesophageal reflux laparoscopic surgery on the perioperative ECG, cardiac troponin I and myocardial enzyme changes.

Improved postoperative analgesia with isoflurane than with propofol anaesthesia

PurposeThe impact of hypnotic drugs on postoperative analgesia has not been evaluated. We compared the influence of the maintenance of anaesthesia with either propofol or isoflurane on postoperative pain.MethodsForty ASA 1 -2 women, undergoing cosmetic abdominoplasty were randomized to receive either 6–12 mg·kg−1·hr−1 propofol iv (P, n = 20) or MAC 1 -1.5 isoflurane inhalation (Iso, n = 20). The lungs were ventilated with N2O 60% and O2 40%, and I μg·kg−1 fentanyliv provided intraoperative analgesia. Before surgical closure, 2 g propacetamoliv were administered. Postoperative analgesia was provided after hourly assessment of pain (VAS 0–100 mm), with 10 mg nalbuphineiv if VAS ≥ 50 mm, during the eight hours after surgery. Sedation score (awake 0 to unrousable 4) was also recorded. Analgesia satisfaction score (nil 0 to excellent 4) obtained from the patient on discharge.ResultsSedation scores were similar in both groups except in the first postoperative hour, when it was higher in the Iso group. The VAS at rest (15.4 ± 18.6 vs 29.7 ± 19.8 mm,P = 0.0001) and nalbuphine requirements (0.13 ± 0.35vs 0.70 ± 0.80 doses,P = 0.004) were lower in the Iso group during the first six hours, although emesis was more frequent than in P (60vs 25%; P = 0.03). The incidence of analgesia satisfaction score (≥3) was similar between the two groups (P: 95; Iso: 75%).ConclusionThese results suggested that isoflurane anaesthesia provides better analgesia than propofol anaesthesia in the first six hours after abdominoplasty.RésuméObjectifAfin d’évaluer l’influence, sur l’analgésie postopératoire, des agents hypnotiques utilisés en anesthésie générale, nous avons comparé le propofol et l’isoflurane.MéthodesQuarante patientes ASA 1–2, devant subir une chirurgie esthétique de la paroi abdominale, ont reçu aléatoirement soit du propofol à 6–12 mg·kg−1·hr−1 (P, n = 20), soit de l’isoflurane à MAC 1–1,5 (Iso, n = 20). Sous N2O 60 %, l’analgésie peropératoire était obtenue par du fentanyliv 1 μg·kg−1. Avant la fermeture chirurgicale, 2 g de propacétamoliv étaient administrés. La douleur postopératoire, évaluée toutes les heures pendant huit heures, par une échelle visuelle analogique (EVA 0–100 mm), était traitée par 10 mg de nalbuphineiv si EVA 50 mm. Un score de sédation (éveillé 0 à comateux 4) était noté durant 8 heures. Un score de satisfaction du patent concernant l’analgésie était recueilli à sa sortie de l’hôpital (nul 0 à excellent 4).RésultatsLes scores de sédation étaient similaires dans les deux groupes, à l’exception d’une valeur plus élevée dans le groupe Iso lors de la première heure postopératoire. Les scores EVA au repos (15,4 ± 18,6vs 29,7 ± 19,8 mm;P = 0,0001) et la consommation de nalbuphine (0,13 ± 0,35vs 0,70 ± 0,80 doses;P = 0,004) étaient plus faibles que dans le groupe Iso pendant les six premières heures, malgré des épisodes de nausées et de vomissements plus fréquents que dans le groupe P (60 vs 25 %;P = 0,03). L’incidence des scores élevés (3) de satisfaction des patients était comparable (P: 95 %; Iso: 75 %).ConclusionCes résultats suggèrent que l’isoflurane, en comparaison avec le propofol, procure une meilleure analgésie pendant les six premières heures postopératoires d’une abdominoplastie.