Hilary Wagner RN, BSN, SRNA Oakland University-Beaumont/MSN-Anesthesia Class of 2013

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AN INTRAOPERATIVE SMALL DOSE OF KETAMINE PREVENTS REMIFENTANIL-INDUCED POSTANESTHETIC SHIVERING Hilary Wagner RN, BSN, SRNA Oakland University- Beaumont/MSN-Anesthesia Class of 2013

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An Intraoperative Small Dose of Ketamine Prevents Remifentanil -Induced Postanesthetic Shivering. Hilary Wagner RN, BSN, SRNA Oakland University-Beaumont/MSN-Anesthesia Class of 2013. - PowerPoint PPT Presentation

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An Intraoperative Small Dose of Ketamine Prevents Remifentanil-Induced Postanesthetic Shivering

An Intraoperative Small Dose of Ketamine Prevents Remifentanil-Induced Postanesthetic ShiveringHilary Wagner RN, BSN, SRNAOakland University-Beaumont/MSN-AnesthesiaClass of 2013

Nakusuji, M., Nakamura, M., Imanaka, N., Tanaka, M., Nomura, M., & Suh, S. H. (2011). An intraoperative small dose of ketamine prevents remifentanil-induced postanesthetic shivering. Anesthesia & Analgesia, 113 (3). IntroductionPublished in the September 2011 edition of Anesthesia & AnalgesiaThe study was approved by the Human Ethics Review Committee of Kansai Denryoku Hospital in Japan

Study Objectives/PurposePostanesthetic shivering (PAS) is frequently encountered in patients after discontinuation of remifentanil infusionRemifentanil is more likely to cause PAS than other opioidsHowever, the exact cause of remifentanil-induced PAS remains undetermined at this timeStudy Objectives/PurposeTo investigate whether or not a ketamine infusion while using remifentanil during gynecological laparotomy cases reduces the incidence of PAS

StudyPatients were enrolled in this study from August 2009 to October 2010Randomized controlled trialProspective studyDependent variable = Postanesthetic shiveringIndependent variable = Ketamine infusion

Inclusion CriteriaASA status of I or IIUnder age 60Surgical time less than 3.5 hours (surgical times longer than 3.5 hours are correlated with PAS)

Patients were automatically excluded if they were:undergoing emergency surgeryscheduled for radical hysterectomyMethodsSigned written consent form was obtained from each subject64 patients meeting inclusion criteria were randomly assigned to receive either 0.5 mg/kg ketamine at induction followed by an infusion of 0.3 mg/kg/hr for the duration of surgery (n=32) or a similar volume of saline (n=32).The patients were randomly assigned via envelope randomization

Methods (cont.)In both groups, all patients received:Midazolam IM (2.5-5 mg) 15 minutes before OR arrivalAn epidural catheter at the T12-L1 interspaceEpidural ropivacaine titrated intraoperatively to maintain systolic arterial blood pressure within 20% or less of preoperative blood pressureGeneral anesthesia induced with propofol at 1.5-2 mg/kg IV and a remifentanil infusion at 0.25-0.5 mcg/kg/min (for analgesia)Vecuronium bromide for tracheal intubation at 0.1 mg/kg IV

Methods (cont.)Total IV anesthesia with propofol titrated to maintain a target Bispectral Index (BIS) value between 30-50FiO2 at 0.40 (a mix of oxygen and air, no nitrous oxide was used)100 mcg of fentanyl via the epidural catheter after closure of the peritoneum1.25 mg of droperidol at the end of the case to prevent postoperative nausea and vomitingForced air blanket to lower extremities at 32C which was discontinued when rectal temperature reached 37CLactated ringers solution infused at ambient temperature of 25-27C

Methods (cont.)The OR staff were unaware as to which patients were part of the experimental and control groupsThe staff monitored the patients for PAS while in the OR and for 30 minutes post-emergenceOutcome Measures(cont.)Measured shivering with a 5-point rating scale0: no shivering1: peripheral vasoconstriction with no visible muscular activity2: visible muscular activity confined to only 1 muscle group3: visible muscular activity in more than 1 muscle group4: gross muscular activity involving the whole bodyA score between 3 and 4 indicated PAS

Methods (cont.)The anesthesia provider remained absent during the PAS evaluation so as not to allow bias related to anesthetic regimen knowledgePostoperative pain was also evaluated using the visual analog scale from 0 (no pain) to 10 (worst pain)PAS was then treated using a warm blanketIf PAS persisted longer than 15 minutes, 50 mg of flurbiprofen axetil was administered (COX inhibitor)

A flow diagram of inclusion and exclusion criteria applied in this study, based on the CONSORT (Consolidated Standards of Reporting Trials) statement.

Nakasuji M et al. Anesth Analg 2011;113:484-487Statistical AnalysisStudent t test and the Mann-Whitney U test were used for statistical comparisonsDifferences between the groups were considered statistically significant when the P value was