1311 Anesthesiology 2000; 92:1311–8 © 2000 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc. Patients with Diabetic Neuropathy Are at Risk of a Greater Intraoperative Reduction in Core Temperature Akira Kitamura, M.D.,* Takeshi Hoshino, M.D.,* Tadashi Kon, M.D.,* Ryo Ogawa, M.D.† Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/92/5/1311/400705/0000542-200005000-00019.pdf by guest on 28 September 2021 Background: Core hypothermia develops after the induction was delayed in patients with autonomic dysfunction compared of general anesthesia, but intraoperative vasoconstriction usu- with the others. ally prevents its progression. However, diabetes mellitus is of- Conclusions: The current results indicate that diabetic auto- ten associated with autonomic neuropathy, which leads to ab- nomic neuropathy is associated with more severe intraopera- normal peripheral neurovascular function. Accordingly, we tive hypothermia. We postulate that diabetic patients become tested the hypothesis that diabetic patients experience a greater more hypothermic because their peripheral neuropathy delays reduction in core temperature during general anesthesia than the onset of thermoregulatory vasoconstriction and reduces its nondiabetic patients. efficacy once triggered. These patients may therefore fail to Methods: We studied 36 nondiabetic patients (control group) develop a normal core temperature plateau. (Key words: Anes- thesia; diabetes; autonomic insufficiency; thermoregulation; and 27 diabetic patients (diabetic group) undergoing elective vasoconstriction.) abdominal surgery. Both groups were divided into young (< 60 yr) and older age (> 60 yr) groups. Standard noninvasive auto- nomic tests (heart rate variation at deep periodical breathing, PERIOPERATIVE hypothermia is common and causes Valsalva maneuver, and head-up tilt) were carried out for each several complications, including postoperative shiver- patient. The relation between the results of these tests of auto- ing, decreased drug metabolism and clearance, and im- nomic function and the tympanic membrane temperature dur- paired wound healing. Hypothermia initially results from ing general anesthesia was assessed in relation to peripheral core-to-peripheral redistribution of body heat and from vasoconstriction. Results: Thirteen patients in the diabetic group showed ab- heat loss exceeding heat production. Progression of hy- normal responses to two or more of the basal autonomic func- pothermia is prevented, however, by the reemergence tion tests (patients with autonomic dysfunction). Changes in of thermoregulatory vasoconstriction,1,2 which de- core temperature among the groups were similar at 90 min after creases cutaneous heat loss3 and retains metabolic heat the induction of anesthesia. However, the core temperature of in the core thermal compartment.4 the diabetic patients with autonomic dysfunction was lower Diabetes mellitus is often associated with autonomic from 120 min (35.1°C) onward compared with the young or dysfunction. It is known that skin and tissue blood flow older nondiabetic patients and the diabetic patients with nor- 5 mal autonomic function. Peripheral vasoconstriction, evaluated are altered in diabetic patients, at least partly as a result 6,7 using the forearm–fingertip skin surface temperature gradient, of impairment of neurogenic control. Peripheral neu- rovascular function is disordered in diabetic patients,8,9 and it is possible that this abnormality prevents effective This article is featured in “This Month in Anesthesiology.” 10 ᭛ Please see this issue of ANESTHESIOLOGY, page 5A. thermoregulatory vasoconstriction. In the current prospective study, we tested the hy- pothesis that the threshold for intraoperative vasocon- striction is reduced in patients with autonomic neurop- * Staff Anesthesiologist. athy and that these patients consequently become more † Professor of Anesthesiology. hypothermic during surgery compared with patients Received from the Department of Anesthesiology, Nippon Medical without autonomic neuropathy. School Hospital, Tokyo, Japan. Submitted for publication June 9, 1999. Accepted for publication December 9, 1999. Supported in part by a grant-in-aid for research (No. 10770772) from the Japanese Ministry of Methods Education, Science and Culture, Tokyo, Japan. Address reprint requests to Dr. Kitamura: Department of Anesthesi- The protocol was reviewed and approved by the ethics ology, Nippon Medical School, Sendagi 1-1-5, Bunkyo-ku, Tokyo 113, committee of our department. Informed consent was Japan. Address electronic mail to: kitamura/[email protected] obtained from all patients. Thirty-six nondiabetic pa- Anesthesiology, V 92, No 5, May 2000 1312 KITAMURA ET AL. Table 1. Demographic and Clinical Characteristics of the Patients Young Group Older Group All Controls DAN-negative DAN-positive Number 19 17 36 14 13 Mean age (yr) 48 Ϯ 28 69 Ϯ 5* 58 Ϯ 13 59 Ϯ 12 62 Ϯ 12 Body mass index (kg/m2) 22.7 Ϯ 2.6 21.8 Ϯ 2.6 22.3 Ϯ 2.6 23.4 Ϯ 3.9 23.7 Ϯ 4.2 Duration of surgery (min) 198 Ϯ 42 185 Ϯ 45 192 Ϯ 43 210 Ϯ 57 191 Ϯ 36 Prior myocardial infarction (cases) 0 0 0 1 3 Retinopathy (cases) 0 2 2 1 3 Painful peripheral neuropathy (cases) 0 0 0 0 3 Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/92/5/1311/400705/0000542-200005000-00019.pdf by guest on 28 September 2021 IDDM (NIDDM) 3 (11) 4 (9) Mean duration of diabetes (yr) 4.9 Ϯ 3.2 6.9 Ϯ 4.7 HbA1C 6.8 Ϯ 1.6 8.0 Ϯ 1.2 Use of vasopressor (ephedrine) (cases) 1 3 4 3 6 Use of insulin (cases) 1 1 2 1 1 Transfusion requirement (cases) 4 6 10 4 4 Total fluid administered (ml/kg) 41.5 Ϯ 10.7 36.7 Ϯ 8.2 39.2 Ϯ 9.8 40.8 Ϯ 10.0 41.40 Ϯ 11.5 Values are mean Ϯ SD. Young group: young controls (Ͻ60 yr old), Older group: elderly controls (Ն60 yr old), DAN: diabetic autonomic neuropathy; IDDM: Insulin-dependent diabetes mellitus; NIDDM: Non-insulin-dependent diabetes mellitus. * P Ͻ 0.05 compared with young group. tients (control group: 19 men and 17 women) and 27 the current study averaged 5.9 yr (range, 5 months–20 diabetic patients (diabetic group: 15 men and 12 yr). The mean HbA1c level in the 27 diabetic patients women) with no history of smoking who were sched- was 7.5 Ϯ 1.5% (table 1). uled for elective abdominal surgery participated in this study. Patients with a body mass index in excess of 28% Autonomic Function Tests were excluded. The age range was wide, but the average All subjects were evaluated no more than 1 day before ages of the control and diabetic groups were compara- surgery. Three standard noninvasive autonomic tests ble. The diabetic and control groups were each divided (heart rate variation at deep periodical breathing, Val- into young and older groups (Ͻ 60 yr of age and Ն 60 yr salva maneuver, and head-up tilt) were carried out for of age, respectively). The criteria for diabetes mellitus each patient.11 The subject was asked to rest comfort- were treatment with insulin or oral hypoglycemic agents ably in the supine position in a quiet room with dim and an elevated fasting glucose level on checkup before lighting. The ECG and the tonometric blood pressure of surgery defined as plasma level of 140 mg/dl or higher the radial artery were monitored continuously (ANS-508, and whole blood level of 120 mg/dl or higher. Each Colin Electronics, Komaki, Japan). Heart rate (HR) was patient underwent a preoperative evaluation which in- detected from lead II of the ECG. A 2-min period of quiet cluded history, physical examination, 12-lead electrocar- breathing was observed with the ECG displayed on an diogram (ECG), chest radiograph, and biochemistry oscilloscope, followed by a period of forceful breathing screening tests. for 3 min which consisted of 1 min of maximum inspira- Basic demographic and clinical data were obtained tory and expiratory efforts (each5sinduration) at a preoperatively, and physical examination was done with frequency of 6 breaths/min. The ratio of the maximum a focus on abnormalities of the pulmonary, cardiac, en- respiratory rate (RR) interval during expiration to the docrine, neurologic, and vascular systems. None of the minimum RR during inspiration (E/I ratio) was calcu- patients were being treated with ␤-adrenergic antago- lated for each breath. The mean E/I ratio during the nists, peripheral vasodilators, diuretics, or central sym- second minute was calculated as the average of the six patholytic agents. Four diabetic patients had Q waves on E/I ratios recorded during this time, and the maximum resting ECG but had not previously evident ischemic E/I ratio was defined as the single largest ratio during the episodes. None had signs or symptoms of heart failure or second minute. Values less than 1.10 were considered unstable cardiac symptoms. Four diabetic patients and abnormal. two control subjects had retinopathy. Among the dia- A 10-min supine recovery period was observed, fol- betic patients, three had chronic painful peripheral neu- lowed by two consecutive Valsalva maneuvers. These ropathy. There were seven type I and 20 type II diabetic consisted of blowing into a mouthpiece connected to a patients, and the time from the diagnosis of diabetes to sphygmomanometer to maintain a pressure of 30 mmHg Anesthesiology, V 92, No 5, May 2000 1313 DIABETIC NEUROPATHY AND INTRAOPERATIVE HYPOTHERMIA for 10 s. Practice sessions were conducted to teach the hematocrit at 25–32%. Fluids were not warmed. Reversal subject how to perform this test. Measurements were of residual muscle paralysis was achieved with neostig- taken after a 2-min rest period between trials. The Val- mine (1.5–2.5 mg) and atropine (0.5–1.0 mg). salva ratio was calculated as the ratio of the longest RR The intraoperative blood glucose level ranged from interval after Valsalva release (phase IV) to the shortest 130–280 mg/dl.