Walter G. Maurer

Remifentanil Compared with Alfentanil for Ambulatory Surgery Using Total Intravenous Anesthesia

The purpose of this study was to test the hypothesis that using a 1:4 ratio of remifentanil to alfentanil, a remifentanil infusion would provide better suppression of intraoperative responses and comparable recovery profiles after ambulatory laparoscopic surgery than an alfentanil infusion, as part of total intravenous anesthesia. Two hundred ASA physical status I, II, or III adult patients participated in this multicenter, double-blind, parallel group study. Patients were randomly assigned 2:1 to either the remifentanil-propofol or alfentanil-propofol regimens. The anesthesia sequence was propofol (2 mg/kg intravenously [IV] followed by 150 micro g [centered dot] kg (-1) [centered dot] min-1), and either remifentanil (1 micro g/kg IV followed by 0.5 micro g [centered dot] kg-1 [centered dot] min-1) or alfentanil (20 micro g/kg IV followed by 2 micro g [centered dot] kg-1 [centered dot] min (-1)), and vecuronium. After trocar insertion, infusion rates were decreased (propofol to 75 micro g [centered dot] kg-1 [centered dot] min-1; remifentanil to 0.25 micro g [centered dot] kg-1 [centered dot] min-1; alfentanil to 1 micro g [centered dot] kg-1 [centered dot] min-1). Alfentanil and propofol were discontinued at 10 and 5 min, respectively, before the anticipated end of surgery (last surgical suture); remifentanil was discontinued at the end of surgery. Recovery times were calculated from the end of surgery. The median duration of surgery was similar between groups (39 min for remifentanil versus 34 min for alfentanil). A smaller proportion of remifentanil patients than alfentanil patients had any intraoperative responses (53% vs 71%, P = 0.029), had responses to trocar insertion (11% vs 32%, P < 0.001), or required dosage adjustments during maintenance (24% vs 41%, P < 0.05). Early awakening times were similar. Remifentanil patients qualified for Phase 1 discharge later and were given postoperative analgesics sooner than alfentanil patients (P < 0.05). Actual discharge times from the ambulatory center were similar between groups (174 min for remifentanil versus 204 min for alfentanil) (P = 0.06). In conclusion, remifentanil can be used for maintenance of anesthesia in a 1:4 ratio compared with alfentanil, for total IV anesthesia in ambulatory surgery. This dose of remifentanil provides more effective suppression of intraoperative responses and does not result in prolonged awakening. (Anesth Analg 1997;84:515-21)

Redefining the preoperative evaluation process and the role of the anesthesiologist

STUDY OBJECTIVE To assess the effects of implementing an ambulatory and same-day surgery preoperative evaluation patient triage system over a 3-year period. DESIGN Retrospective analysis of 63,941 ambulatory surgical patients presenting for elective surgery. SETTING Tertiary care, academic medical institution. INTERVENTIONS The following preoperative evaluation model components were implemented over a 3-year period: HealthQuest, which is an outpatient preoperative assessment computer program developed by the Department of General Anesthesiology; a general internal medicine clinic designated specifically for preoperative evaluation and medical optimization; disease specific algorithms for both preoperative patient assessment and management; and a preoperative anesthesia clinic that no longer performs preoperative medical optimization. MEASUREMENTS AND MAIN RESULTS During the 3-year study period ambulatory and same-day surgical case volume increased 34.7%. A total of 50,967 patients used HealthQuest as part of their preoperative evaluation. Of these patients 22,744 (35.6%) did not need to see an anesthesiologist until the day of surgery as guided by both a computer-assigned HealthQuest score and surgical classification scheme. Also, 41,197 patients were evaluated in our anesthesia preoperative clinic with a cost per evaluation of

Remifentanil versus remifentanil/midazolam for ambulatory surgery during monitored anesthesia care.

24.86, which increased only 0.9% per year. In addition, both patient interview time and patient dissatisfaction with the preoperative process decreased over the 3-year period. There were 20, 088 patient encounters in the general internal medicine clinic for patient medical evaluation and optimization. The average monthly preoperative surgical delay rate decreased 49% during the study period. Finally, significant monetary saving resulted due to decreased unnecessary laboratory testing. CONCLUSIONS Efficient, cost-effective patient care can be provided by using this preoperative evaluation model. Some institutions may find portions of this preoperative model applicable to their current situation.

Effects of topical nitroglycerin and intravenous lidocaine on propofol-induced pain on injection.

Background: This study was designed to define the appropriate dose of remifentanil hydrochloride alone or combined with midazolam to provide satisfactory comfort and maintain adequate respiration for a monitored anesthesia care setting. Methods: One hundred fifty‐nine patients scheduled for outpatient surgery participated in this multicenter, double‐blind study. Patients were randomly assigned to one of two groups: remifentanil, 1 micro gram/kg, given over 30 s followed by a continuous infusion of 0.1 micro gram [center dot] kg sup ‐1 [center dot] min sup ‐1 (remifentanil); remifentanil, 0.5 micro gram/kg, given over 30 s followed by a continuous infusion of 0.05 micro gram [center dot] kg sup ‐1 [center dot] min sup ‐1 (remifentanil + midazolam). Five minutes after the start of the infusion, patients received a loading dose of saline placebo (remifentanil) or midazolam, 1 mg, (remifentanil + midazolam). If patients were not oversedated, a second dose of placebo or midazolam, 1 mg, was given. Remifentanil was titrated (in increments of 50% from the initial rate) to limit patient discomfort or pain intraoperatively, and the infusion was terminated at the completion of skin closure. Results: At the time of the local anesthetic, most patients in the remifentanil and remifentanil + midazolam groups experienced no pain (66% and 60%, respectively) and no discomfort (66% and 65%, respectively). The final mean (+/‐ SD) remifentanil infusion rates were 0.12 +/‐ 0.05 micro gram [center dot] kg sup ‐1 [center dot] min sup ‐1 (remifentanil) and 0.07 +/‐ 0.03 micro gram [center dot] kg sup ‐1 [center dot] min sup ‐1 (remifentanil + midazolam). Fewer patients in the remifentanil + midazolam group experienced nausea compared with the remifentanil group (16% vs. 36%, respectively; P < 0.05). Four patients (5%) in the remifentanil group and two patients (2%) in the remifentanil + midazolam group experienced brief periods of oxygen desaturation (SpO2 < 90%) and hypoventilation (< 8 breaths/min). Conclusions: Remifentanil alone or combined with midazolam provided adequate analgesia and maintained adequate respiration at the doses reported. The low dose of remifentanil combined with 2 mg midazolam, compared with remifentanil alone, resulted in fewer side effects, slightly greater sedation, and less anxiety.

Six sigma methodology can be used to improve adherence for antibiotic prophylaxis in patients undergoing noncardiac surgery.

We performed a randomized, placebo-controlled, double-blind study to compare the efficacy of intravenous (IV) lidocaine and topical nitroglycerin ointment in preventing pain during propofol injection. Nitroglycerin or placebo ointments were applied to the back of the hand over the skin area overlying the IV catheter tip; lidocaine was or was not added to the propofol solution. One hundred twenty-four patients were randomly assigned to receive one of four treatments: placebo and plain propofol, propofol mixed with lidocaine, nitroglycerin ointment and plain propofol, and nitroglycerin ointment and propofol mixed with lidocaine. Hence, there were 31 patients in each treatment group. Patients receiving nitroglycerin ointment and plain propofol had the highest incidence of pain on propofol injection (23 of 31 patients, 74%), and the highest median pain score. Only when lidocaine was added to propofol did it effectively reduce the incidence and severity of pain. Patients aged 50 yr and older had a significantly lower incidence and less severe pain. We conclude that lidocaine and age, but not topical nitroglycerin ointment, are factors associated with a decreased incidence of propofol-induced pain. (Anesth Analg 1997;84:865-9)

A Randomized Comparison of Gasless Laparoscopy and CO2 Pneumoperitoneum

BACKGROUND:Six Sigma methodology is a data management process that can be used to achieve a goal of near perfection in process performance. An audit of 615 surgeries over 2 mo revealed only 38% of noncardiac patients admitted on the day of surgery at our institution received perioperative antimicrobial prophylaxis within the target interval of ≤60 min before incision. METHODS:Six Sigma methodology was used to improve our process of timing of antimicrobial prophylaxis administration. A multidisciplinary team was assembled which identified seven process inputs by which patients receive antimicrobial prophylaxis. Interventions for improvement included reinforcement of use of preoperative antibiotic order forms, eliminating administration of antibiotics in the preoperative admission area, and sending appropriate antibiotics and IV tubing with the patient to the operating room. We concurrently developed a control plan to sustain this improvement using a recently deployed electronic anesthesia record keeping system using real-time measurement and reporting capabilities of antimicrobial prophylaxis administration. After defining the new process and undertaking a system-wide educational effort, implementation was begun with data collection and analysis occurring over the next 7 mo. RESULTS:For the 8-mo postintervention interval, there was a significant improvement with 86% of 1716 surgical patients receiving their antibiotic prophylaxis within the specified time frame (P < 0.01). The time interval for antibiotic administration before surgical incision also decreased from a preintervention mean of 88 (CI 56–119 min) to 38 min (CI 25–51 min) (P < 0.01). CONCLUSION:We conclude that Six Sigma methods were used to successfully improve our process for timing of perioperative antibiotic prophylaxis before surgical incision. An electronic anesthesia record keeping system is a useful tool to monitor this process improvement.

Does general anesthesia increase the diagnostic yield of endoscopic ultrasound-guided fine needle aspiration of pancreatic masses?

Abstract Objective: To determine if the theoretic advantages of gasless laparoscopy are realized in direct comparison to laparoscopy with pneumoperitoneum. Methods: Fifty-seven patients undergoing laparoscopic surgery chose to participate in this trial and were randomized after the induction of general anesthesia. Twenty-nine of the 57 patients were randomized to the pneumoperitoneum group. Of the 28 patients in the gasless group, six were converted to pneumoperitoneum because of inadequate exposure. The adequacy of exposure and ease of surgery were assessed with a subjective score, and the times to exposure and for incision closure were recorded. Various anesthetic factors were measured. Patients completed an analog pain score in the recovery area and for the first 5 postoperative days. Analgesic and antiemetic use also was recorded, as was the number of days to return to normal activity. Results: Times to achieve exposure and close incisions were longer, and exposure and ease of surgery were worse in the gasless group. Patients in the gasless group had lower diastolic blood pressure, minute ventilation, peak inspiratory pressures, and end tidal pCO 2 . There were no differences in body temperature, systolic blood pressure or heart rate, postoperative pain scores, analgesic or antiemetic use, or times to hospital discharge or return to activity between the groups. Conclusion: Performing laparoscopy using the Laparolift device compromised surgical exposure and thus increased technical difficulty. Patients realized no benefits from its use in terms of postoperative discomfort or return to activity. Eliminating the pneumoperitoneum allowed lower minute ventilation and peak inspiratory pressures, and end tidal pCO 2 was lower. Although the concept of gasless laparoscopy holds appeal, the current prototype is not well-suited for infertility procedures.

Remifentanil provides better analgesia than alfentanil during breast biopsy surgery under monitored anesthesia care

Background:Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of the pancreas has become the preferred method for tissue diagnosis for pancreatic solid masses. The yield of EUS-FNA in this setting is influenced by multiple factors. We hypothesized that general anesthesia (GA) may improve EUS-FNA yield by improving patient cooperation and stillness during the procedure. Our objective was to assess the association between the sedation method employed and the diagnostic yield of EUS-FNA. Methods:A retrospective cohort study was conducted involving consecutive patients who received EUS-FNA for diagnosis of a solid pancreatic mass at the Cleveland Clinic (Cleveland, OH) gastrointestinal endoscopy units from 2007 to 2009. We compared the diagnostic yield of EUS-FNA between patients receiving GA provided by an anesthesiologist (GA group) and patients receiving conscious sedation (CS) provided by a qualified registered nurse (CS group). Results:Of 371 patients, a cytological diagnosis was obtained in 73/88 patients (83%) in the GA group and 206/283 patients (73%) in the CS group. Anesthesiologist-delivered GA was associated with an increased odds of having a successful diagnosis as compared with CS (adjusted odds ratio [95% CI]: 2.56 [1.27–5.17], P = 0.01). However, the incidence of complication during or after the procedure was not different between the groups (P > 0.99). Conclusions:Anesthesiologist-delivered GA was associated with a significantly higher diagnostic yield of EUS-FNA. GA should be considered a preferred sedation method for EUS-FNA of a solid pancreatic mass.

Comparison of neuromuscular effects, efficacy and safety of rocuronium and atracurium in ambulatory anaesthesia

PurposeTo compare the analgesic effects of remifentanil and alfentanil during breast biopsy under monitored anesthesia care (MAC).MethodsSixty patients received sedation with propofol (50 μg· kg−1·min−1). After receiving a loading dose of opioid (either remifentanil 0.5 μg· kg−1, or alfentanil 2.5 μg· kg−1), an infusion was initiated (remifentanil 0.05 μg· kg−1· min−1 or alfentanil 0.25 μg· kg−1· min−1), and this was supplemented with local anesthetic infiltration. The pain was evaluated with aten-point visual analogue scale (VAS) during local anesthetic infiltration and deep tissue dissection. Inadequate analgesia, defined as VAS scores ≥ 5, was treated first with boluses of opioid (remifentanil group 10 μg or alfentanil group 50 μg) and if inadequate after two treatments with additional local anesthetic. Postoperative times were recorded including the times until discharge criteria were achieved and patient’s actual discharge.ResultsThe pain scores were similar between the two groups during the initial injections of local anesthetic in the breast, however, patients in the remifentanil group had lower mean pain scores during deep tissue dissection (2.3vs 4.3,P < 0.01). Patients in the remifentanil group required fewer rescue doses of opioid (1.9 vs 3.6,P < 0.03) and local anesthetic (5 vs 15,P < 0.006). The two study groups had comparable speed of recovery.ConclusionRemifentanil was a better opioid choice than alfentanil for breast biopsy under MAC at the doses studied, but it did not increase the rapidity in which patients recovered postoperatively.RésuméObjectifComparer les effets analgésiques du rémifentanil et de l’alfentanil pendant la biopsie mammaire sous surveillance anesthésique (SA).MéthodeSoixante patientes ont reçu une sédation avec du propofol (50 μg· kg−1· min−1). Après une dose de charge d’opioïde (soit le rémifentanil 0,5 )μg· kg−1 ou l’alfentanil 2,5 μg · kg−1), une perfusion a été amorcée (0,05 )μg · kg−1 · min−1 de rémifentanil ou 0,25 μg · kg−1· min−1 d’alfentanil) et complétée par une infiltration d’anesthésique local. La douleur a été évaluée avec une échelle visuelle analogique en dix points (EVA) pendant l’infiltration et la dissection des tissus profonds. L’analgésie incomplète, définie par un score ≥ 5 à l’EVA, a été traitée d’abord avec des bolus d’opioïde (10 μg de rémifentanil ou 50 μg d’alfentanil), puis avec un anesthésique local si l’analgésie était incomplète après deux doses. Après l’opération, nous avons noté le délai nécessaire à l’atteinte des critères de sortie et le temps réel avant la sortie des patientes.RésultatsLes scores de douleur ont été similaires dans les deux groupes pendant les injections initiales d’anesthésique local dans le sein, quoique les patientes qui ont reçu le rémifentanil aient présenté des scores de douleur moyens plus bas pendant la dissection tissulaire (2,3 vs 4,3, P < 0,01). Les patientes sous rémifentanil ont demandé moins d’opioïde de secours (1,9 vs 3,6, P < 0,03) et d’anesthésique local (5 vs 15, P < 0,006). Les temps de récupération ont été comparables entre les groupes.ConclusionLe choix du rémifentanil s’est révélé meilleur que celui de l’alfentanil pour la biopsie mammaire sous SA aux doses étudiées, mais n’a pas raccourci la récupération postopératoire.

Sufentanil-isoflurane-nitrous oxide anesthesia for a patient treated with monoamine oxidase inhibitor and tricyclic antidepressant

PurposeTo compare the neuromuscular effects, efficacy, and safety of equi-effective doses of rocuronium and atracurium in ambulatory female patients undergoing surgery.MethodsForty-one patients undergoing laparoscopic gynaecological surgery were randomized to receive 2 × ED90 rocuronium (0.6 mg·kg−1; n = 20) or atracurium (0.5 mg·kg−1; n = 21) during intravenous propofol/alfentanil anaesthesia with N2O/O2 ventilation. Neuromuscular block was measured with a mechanomyogram eliciting a train-of-four (TOF) response at the wrist. Intubation conditions 60 sec after administration of muscle relaxant and immediate cardiovascular disturbances or adverse events during the hospital stay were noted by blinded observers.ResultsCompared with atracurium, rocuronium was associated with a shorter onset time (59.0 ± 22.2vs 98.6 ± 41.4 sec;P < 0.001) and clinical duration of action (33.3 ± 7.1vs 44.7 ± 7.2 min;P < 0.001), but longer spontaneous recovery index (9.6 ± 2.41vs 6.9 ± 1.89 min;P = 0.023) and a similar time to spontaneous recovery to TOF 70%; 53 ± 6.31vs 59.2 ± 7.59 min;P =0.139). Tracheal intubation was accomplished in < 90 sec in all patients receiving rocuronium but in only 14 of 21 patients receiving atracurium. The incidence of adverse events and the cardiovascular profiles for the two drugs were similar, although one patient receiving atracurium experienced transient flushing of the head and neck.ConclusionRocuronium has minimal side effects, provides conditions more suitable for rapid tracheal intubation, and is associated with a shorter clinical duration than atracurium. Once begun, the spontaneous recovery profile of rocuronium is slightly slower than that of atracurium.RésuméObjectif p]Comparer les effets neuromusculaires, l’efficacité et la sécurité de doses à effet équivalent de rocuronium et d’atracurium chez des patientes devant subir une chirurgie ambulatoire.MéthodeQuarante-deux patientes réparties au hasard et devant subir une laparoscopie gynécologique ont reçu 2 × ED90 de rocuronium (0,6 mg·kg−1; n = 20) ou d’atracurium (0,5 mg·kg−1; n = 21) pour une anesthésie intraveineuse avec propofol et alfentanil sous ventilation avec N2O et O2. Le blocage neuromusculaire a été mesuré à l’aide d’un mécanomyogramme enregistrant, au poignet, une réponse en train-de-quatre (TDQ). Pendant le séjour à l’hôpital, des observateurs impartiaux ont noté l’état de l’intubation 60 s après l’administration du relaxant musculaire, et les perturbations cardiovasculaires ou les réactions indésirables immédiatement après leur survenue.RésultatsComparé à l’atracurium, le rocuronium a été associé à une induction plus courte (59,0 ± 22,2vs 98,6 ± 41,4 s;P < 0,001) et à une action clinique plus brève (33,3 ± 7, 1vs 44,7 ± 7,2 min;P < 0,001), mais à un index de récupération spontanée plus long (9,6 ± 2,41vs 6,9 ± 1,89 min;P = 0,023) et à une durée similaire de récupération spontanée au TDQ 70 % (53 ± 6,31vs 59,2 ± 7,59 min;P = 0,139). L’intubation endotrachéale a eu lieu en moins de 90 s chez toutes les patientes qui ont reçu du rocuronium mais chez seulement 14 des 21 patientes ayant reçu de l’atracurium. Lincidence de réactions indésirables et les profils cardiovasculaires ont été semblables avec les deux médicaments, quoiqu’une patiente ayant reçu de l’atracurium ait manifesté des bouffées vasomotrices à la tête et au cou.ConclusionLe rocuronium présente moins d’effets secondaires, permet une intubation endotrachéale plus rapide et est associé à un effet clinique plus court que l’atracurium. Une fois amorcée, la récupération spontanée est légèrement plus lente qu’avec l’atracurium.