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E Poster discussion: Circulation

Abstract PR040: Hypotension in Diabetics At Induction of Anaesthesia - A Predictable Phenomenon? Preliminary Data From An Ongoing Study.

Olsson, J. E. P.1,*; Buch, N. S.1; Pedersen, A. S. B.1; Tarnow, L.2; Lange, K.3; Fleischer, J.4; Espelund, U. S.1

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doi: 10.1213/01.ane.0000492450.16536.64
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Background & Objectives: Patients with diabetes are at increased risk of complications and death in the peri-operative period compared to non-diabetics. Cardiac autonomic neuropathy (CAN) is a frequent complication of type 1 and 2 diabetes, attenuating the compensatory response of the cardiovascular system to anaesthesia[1]. The resulting hypotension may lead to ischemia of vital organs. We hypothesize that the presence of CAN is associated with peri-operative hypotension.

The purpose of this study is to investigate the utility of pre-operative screening for CAN to predict peri-operative hypotension and the vasopressor need amongst diabetic patients.

Materials & Methods: Diabetic patients undergoing elective surgery in general- or spinal anaesthesia are recruited into a double-blinded cross-sectional study. The presence of CAN is investigated days to weeks prior to surgery by internationally accepted standard tests: i) heart rate variability during 5 minutes´ rest (HRV-5), ii) paced breathing, iii) posture change, and iv) Valsalva’s maneuvre[2].

Current medication, type, duration and possible late complications of diabetes are recorded. The patient’s blood pressure is measured non-invasively on both arms. Peri-operative data are extracted from the anaesthesia record.

Results: We present data (mean ±sd) from 26 diabetic patients, of whom 22 had type 2 diabetes. The average age and BMI were 62±9 years and 31±6 kg/m2, respectively. All patients underwent general anaesthesia. The preliminary analysis show an association between HRV-5 and hypotension during the induction of anaesthesia (i.e. from the administration of a sedative bolus medication and the subsequent 10 minutes). Linear regression analysis showed that a lower HRV-5 was associated with a greater decrease in blood pressure (P=0.01).

When stratified by low, medium, and high HRV-5, the lowest measured mean arterial blood pressure (MAP) was 58±18, 60±9, 71±14 mmHg, respectively. Furthermore, patients with a dip in MAP below 60 mmHg tended to have a lower HRV-5 compared to the other patients (P=0.06). The remaining CAN tests were not associated with MAP.

Conclusion: The preliminary results show that peri-operative hypotension is associated with HRV-5. Once the study is completed, we are able to assess the utility of CAN screening to predict peri-operative hypotension. If successful, a pre-operative screening for CAN may aid the planning of cardiovascular monitoring during anaesthesia.

References:

1.Huang et al. Pre-operative measurement of heart rate variability predicts hypotension during general anesthesia. Acta Anaesthesiol Scand. 2006 May;50(5):542–8

2.Vinik et al. Diabetic autonomic neuropathy. Diabetes Care. 2003 May;26(5): 1553–79.

Disclosure of Interest: None declared

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