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4770
Hemodynamic Effects of Combining a Brachial Plexus Block with General Anesthesia in Shoulder Arthroscopy
Session: MP-05a
Fri, April 20, 8-9:30 am
Shubert (Shubert Complex), 6th floor

Please note, medically challenging cases are removed three months after the meeting and scientific abstracts after three years.

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Hemodynamic Effects of Combining a Brachial Plexus Block with General Anesthesia in Shoulder Arthroscopy                     Lawrence S. Lipana M.D., Andrew Burzynski M.D., Nitin Sukumar M.S., Feng Dai Ph.D., Jinlei Li M.D. Ph.D.

Department of Anesthesiology, Yale School of Medicine, New Haven, CT

 

Background

ØCombining general anesthesia (GA) with a peripheral nerve block (PNB) has been shown to provide better control of vital signs, airway protection and post-operative pain1.
ØOlder studies showed that combining GA with a PNB in shoulder surgery was associated with intraoperative hypotension2. Recent studies demonstrated safety in ASA 1 & 2 patients.
ØWe performed a retrospective review at Yale and unexpectedly found higher blood pressures in a narrower range in patients who received GA and a PNB in shoulder arthroscopy.
 
Methods
ØInternational review board approval was granted by Yale University.
ØShoulder arthroscopies with rotator cuff repair from Jan through Dec 2016 were reviewed.
ØAll subjects were outpatients.  No patients required exclusion for bacteremia, septicemia or other clinical causes for hypotension.  We excluded patients who received total intravenous anesthetic or monitored anesthesia care to allow the comparison of volatile anesthetic levels.
ØNerve blocks were performed by the institutional standard, which entailed a single shot interscalene or supraclavicular block with 30mL of 0.5% ropivacaine.
ØDemographics collected included age, gender, ASA status, and HTN history.   Intraoperative variables collected included total surgery time, mean percent of inspired and expired sevoflurane and blood pressures during the case.  Vasopressor drugs reviewed included phenylephrine, ephedrine, epinephrine, and vasopressin.
ØThe block and non-block group were compared using either Chi-square tests or Fisher’s exact tests (sparse tables) for categorical variables and either t tests or Wilcoxon rank sum test for continuous variables. 
 
Discussion
ØContrary to older studies, GA + PNB showed higher minimum blood pressure (BP) and a narrower range of blood pressures.
ØIncreased BPs most likely secondary to decreased sevoflurane requirements. BP variability in GA group from lack of protocol.
ØThe intact sympathetic response in non-block patients3, shown to be associated with heart rate variability4, may play a secondary role.
ØHypertension group had comparable pressures despite less arterial stability and compliance5.
ØThis study suggests that GA and PNB can be safely combined from hemodynamic standpoint, even in high risk subgroups with potentially higher risks of mortality from hypotension.
ØDecreased sevoflurane allows for secondary benefit of decreased cost and carbon emissions6.

 

1. Fredrickson M., et al. Postoperative Analgesia for Shoulder Surgery: A Critical Appraisal and

Review of Current Techniques. Anaesthesia 2010; 65:608-24.

2. Ozzeybek D, Oztekin S, Mavioglu O: Comparison of the haemodynamic effects of interscalene block combined with general anaesthesia and interscalene block alone for shoulder surgery. J Int Med Res 2003, 31:428–433.

3. Kim JH, Song SY, Ryu T, Choi CH, Sung SY, Roh WS. Changes in heart rate variability after sitting following interscalene block. Clin Auton Res (2015) 25:327–333.

4. Simeoforidou M, Vretzakis G, Chantzi E, Bareka M, Tsiaka K, Iatrou C, Karachalios T (2013) Effect of interscalene brachial plexus block on heart rate variability. Korean J Anesthesiol 64:432–438.

5. Lapage KG, Wouters PF. The patient with hypertension undergoing surgery. Curr Opin Anaesthesiol. 2016;29:397–402. 

6. Sherman J, Le C, Lamers V et al. Life cycle greenhouse gas emissions of anesthetic drugs. Anesth Analg 2012;114:1086–90. 

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