Anesthetic considerations in diabetic patients. Part I: preoperative considerations of patients with diabetes mellitus

The effect of dexmedetomidine on liver injury secondary to lower extremity ischemia-reperfusion in a diabetic rat model

Introduction: In this study, we aimed to evaluate the hepatic protective effects of dexmedetomidine in the lower extremity ischemia-reperfusion model in diabetic rats biochemically and histopathologically.Methods: Rats were randomly divided into 4 equal groups (n = 6); Control (C) group, diabetic control group (DM), diabetic ischemia-reperfusion group (IR), group with diabetic IR and dexmedetomidine (DEX). In the IR and DEX groups were performed 120 min reperfusion after 120 min ischemia. In group DEX, 100 µ / kg dexmedetomidine was administered intraperitoneally 30 minutes before renal IR administration. Then, various histopathological and biochemical parameters were evaluated in liver tissue.Results: After ischemia-reperfusion, aspartate amino transaminase, alanine amino transaminase, total oxidant level, and thiobarbituric acid -reactive substances were increased, total thiol group and total antioxidant level were decreased and these parameters were found to improve in the group given dexmedetomidine. It was also observed that there was histopathological deterioration after ischemia-reperfusion and histopathological deterioration was found to be less with dexmedetomidine administration.Conclusion: The effects of lower extremity ischemia-reperfusion on hepatic tissue as distant organs were evaluated in diabetic rats, histopathologically, immunologically, biochemically, and liver damage was determined after ischemia-reperfusion, and dexmedetomidine was found to decrease liver damage.

Perioperative management of adult diabetic patients. Preoperative period

In diabetic patients undergoing surgery, we recommend assessing glycaemic control preoperatively by assessing glycated haemoglobin (HbA1c) levels and recent capillary blood sugar (glucose) levels, and to adjust any treatments accordingly before surgery, paying particular attention to specific complications of diabetes. Gastroparesis creates a risk of stasis and aspiration of gastric content at induction of anaesthesia requiring the use of a rapid sequence induction technique. Cardiac involvement can be divided into several types. Coronary disease is characterised by silent myocardial ischaemia, present in 30-50% of T2D patients. Diabetic cardiomyopathy is a real cause of heart failure. Finally, cardiac autonomic neuropathy (CAN), although rarely symptomatic, should be investigated because it causes an increased risk of cardiovascular events and a risk of sudden death. Several signs are suggestive of CAN, and confirmation calls for close perioperative surveillance. Chronic diabetic kidney disease (diabetic nephropathy) aggravates the risk of perioperative acute renal failure, and we recommend measurement of the glomerular filtration rate preoperatively. The final step of the consultation concerns the management of antidiabetic therapy. Preoperative glucose infusion is not necessary if the patient is not receiving insulin. Non-insulin drugs are not administered on the morning of the intervention except for metformin, which is not administered from the evening before. The insulins are injected at the usual dose the evening before. The insulin pump is maintained until the patient arrives in the surgical unit. It should be remembered that insulin deficiency in a T1D patient leads to ketoacidosis within a few hours.

Operating department practitioners care of the patient with diabetes in the perioperative period

Diabetes mellitus (DM) is a of group metabolic diseases which are defined by hyperglycaemia affecting multiple organs. The condition is found in people of all ages and ethnicities. Diabetes mellitus affects 180 million people worldwide and increasing numbers of patients are presenting with diabetic complications and the need for surgical intervention. This article describes the pathophysiology of DM and the management of the condition, particularly type I and type 2, in the perioperative phase of the surgical patient journey.

[Evaluation and perioperative management of patients with diabetes mellitus. A challenge for the anesthesiologist]

Diabetes mellitus (DM) is characterized by alteration in carbohydrate metabolism, leading to hyperglycemia and increased perioperative morbidity and mortality. It evolves with diverse and progressive physiological changes, and the anesthetic management requires attention regarding this disease interference in multiple organ systems and their respective complications. Patient's history, physical examination, and complementary exams are important in the preoperative management, particularly glycosylated hemoglobin (HbA1c), which has a strong predictive value for complications associated with diabetes. The goal of surgical planning is to reduce the fasting time and maintain the patient's routine. Patients with Type 1 DM must receive insulin (even during the preoperative fast) to meet the basal physiological demands and avoid ketoacidosis. Whereas patients with Type 2 DM treated with multiple injectable and/or oral drugs are susceptible to develop a hyperglycemic hyperosmolar state (HHS). Therefore, the management of hypoglycemic agents and different types of insulin is fundamental, as well as determining the surgical schedule and, consequently, the number of lost meals for dose adjustment and drug suspension. Current evidence suggests the safe target to maintain glycemic control in surgical patients, but does not conclude whether it should be obtained with either moderate or severe glycemic control.

Evaluation and perioperative management of patients with diabetes mellitus. A challenge for the anesthesiologist

Diabetes mellitus (DM) is characterized by alteration in carbohydrate metabolism, leading to hyperglycemia and increased perioperative morbidity and mortality. It evolves with diverse and progressive physiological changes, and the anesthetic management requires attention regarding this disease interference in multiple organ systems and their respective complications. Patient's history, physical examination, and complementary exams are important in the preoperative management, particularly glycosylated hemoglobin (HbA1c), which has a strong predictive value for complications associated with diabetes. The goal of surgical planning is to reduce the fasting time and maintain the patient's routine. Patients with Type 1 DM must receive insulin (even during the preoperative fast) to meet the basal physiological demands and avoid ketoacidosis. Whereas patients with Type 2 DM treated with multiple injectable and/or oral drugs are susceptible to develop a hyperglycemic hyperosmolar state (HHS). Therefore, the management of hypoglycemic agents and different types of insulin is fundamental, as well as determining the surgical schedule and, consequently, the number of lost meals for dose adjustment and drug suspension. Current evidence suggests the safe target to maintain glycemic control in surgical patients, but does not conclude whether it should be obtained with either moderate or severe glycemic control.

Effects of dexmedetomidine on renal tissue after lower limb ischemia reperfusion injury in streptozotocin induced diabetic rats

AIM

The aim of this study was to investigate whether dexmedetomidine - administered before ischemia - has protective effects against lower extremity ischemia reperfusion injury that induced by clamping and subsequent declamping of infra-renal abdominal aorta in streptozotocin-induced diabetic rats.

MATERIAL AND METHODS

After obtaining ethical committee approval, four study groups each containing six rats were created (Control (Group C), diabetes-control (Group DM-C), diabetes I/R (Group DM-I/R), and diabetes-I/R-dexmedetomidine (Group DM-I/R-D). In diabetes groups, single-dose (55 mg/kg) streptozotocin was administered intraperitoneally. Rats with a blood glucose level above 250 mg/dl at the 72nd hour were accepted as diabetic. At the end of four weeks, laparotomy was performed in all rats. Nothing else was done in Group C and DM-C. In Group DM-I/R, ischemia reperfusion was produced via two-hour periods of clamping and subsequent declamping of infra-renal abdominal aorta. In Group DM-I/R-D, 100 μg/kg dexmedetomidine was administered intraperitoneally 30 minutes before ischemia period. At the end of reperfusion, period biochemical and histopathological evaluation of renal tissue specimen were performed.

RESULTS

Thiobarbituric acid reactive substance (TBARS), Superoxide dismutase (SOD), Nitric oxide synthase (NOS), Catalase (CAT) and Glutathion S transferase (GST) levels were found significantly higher in Group DM-I/R when compared with Group C and Group DM-C. In the dexmedetomidine-treated group, TBARS, NOS, CAT, and GST levels were significantly lower than those measured in the Group D-I/R. In histopathological evaluation, glomerular vacuolization (GV), tubular dilatation (TD), vascular vacuolization and hypertrophy (VVH), tubular cell degeneration and necrosis (TCDN), tubular hyaline cylinder (THC), leucocyte infiltration (LI), and tubular cell spillage (TCS) in Group DM-I/R were significantly increased when compared with the control group. Also, GV, VVH, and THC levels in the dexmedetomidine-treated group (Group DM-I/R-D) were found significantly decreased when compared with the Group DM-I/R.

CONCLUSION

We found that dexmedetomidine - 100 μg/kg intraperitoneally - administered 30 minutes before ischemia in diabetic rats ameliorates lipid peroxidation, oxidative stress, and I-R-related renal injury. We suggest that dexmedetomidine administration in diabetic rats before I/R has renoprotective effects.

Cardiac Autonomic Neuropathy in Patients with Type 2 Diabetes Mellitus at High Risk for Foot Ulcers

AIM

To study the prevalence of cardiac autonomic neuropathy (CAN) in patients with Type 2 diabetes mellitus at high risk for foot ulcers.

MATERIALS AND METHODS

We screened patients attending diabetic clinic for identifying patients at high risk for foot ulcers. Those with foot risk category 1, 2 and 3 as per criteria of Foot Care Interest Group were subjected to battery of cardiovascular autonomic reflex tests. Those with one abnormal test were termed as probable CAN and those with two abnormal tests as definite CAN. Those with postural fall in blood pressure with one other abnormal test were termed to have advanced CAN.

RESULTS

A total of 74 patients were recruited in the study. The prevalence of abnormal cardiovascular autonomic reflex test was sustained hand grip 81%, E/I ratio 66.2%, 30:15 ratio 28.3% and orthostatic hypotension 13.5%. The prevalence of possible CAN was 31.0% (23/74) and definite CAN was 66.2% (49/74). Ten patients had advanced CAN. There was no observable difference in presence of probable or definite CAN in three risk category for foot ulcers.

CONCLUSION

We found a high prevalence of CAN in subgroup of diabetic patients at increased risk for foot ulcer.

Diabetes and cardiac autonomic neuropathy: Clinical manifestations, cardiovascular consequences, diagnosis and treatment

Cardiac autonomic neuropathy (CAN) is a frequent chronic complication of diabetes mellitus with potentially life-threatening outcomes. CAN is caused by the impairment of the autonomic nerve fibers regulating heart rate, cardiac output, myocardial contractility, cardiac electrophysiology and blood vessel constriction and dilatation. It causes a wide range of cardiac disorders, including resting tachycardia, arrhythmias, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction and increased rate of mortality after myocardial infarction. Etiological factors associated with autonomic neuropathy include insufficient glycemic control, a longer period since the onset of diabetes, increased age, female sex and greater body mass index. The most commonly used methods for the diagnosis of CAN are based upon the assessment of heart rate variability (the physiological variation in the time interval between heartbeats), as it is one of the first findings in both clinically asymptomatic and symptomatic patients. Clinical symptoms associated with CAN generally occur late in the disease process and include early fatigue and exhaustion during exercise, orthostatic hypotension, dizziness, presyncope and syncope. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Medical therapies, including aldose reductase inhibitors, angiotensin-converting enzyme inhibitors, prostoglandin analogs and alpha-lipoic acid, have been found to be effective in randomized controlled trials. The following article includes the epidemiology, clinical findings and cardiovascular consequences, diagnosis, and approaches to prevention and treatment of CAN.

Cardiac autonomic neuropathy in patients with diabetes mellitus

Cardiac autonomic neuropathy (CAN) is an often overlooked and common complication of diabetes mellitus. CAN is associated with increased cardiovascular morbidity and mortality. The pathogenesis of CAN is complex and involves a cascade of pathways activated by hyperglycaemia resulting in neuronal ischaemia and cellular death. In addition, autoimmune and genetic factors are involved in the development of CAN. CAN might be subclinical for several years until the patient develops resting tachycardia, exercise intolerance, postural hypotension, cardiac dysfunction and diabetic cardiomyopathy. During its sub-clinical phase, heart rate variability that is influenced by the balance between parasympathetic and sympathetic tones can help in detecting CAN before the disease is symptomatic. Newer imaging techniques (such as scintigraphy) have allowed earlier detection of CAN in the pre-clinical phase and allowed better assessment of the sympathetic nervous system. One of the main difficulties in CAN research is the lack of a universally accepted definition of CAN; however, the Toronto Consensus Panel on Diabetic Neuropathy has recently issued guidance for the diagnosis and staging of CAN, and also proposed screening for CAN in patients with diabetes mellitus. A major challenge, however, is the lack of specific treatment to slow the progression or prevent the development of CAN. Lifestyle changes, improved metabolic control might prevent or slow the progression of CAN. Reversal will require combination of these treatments with new targeted therapeutic approaches. The aim of this article is to review the latest evidence regarding the epidemiology, pathogenesis, manifestations, diagnosis and treatment for CAN.

Cardiovascular autonomic neuropathy in diabetes: clinical impact, assessment, diagnosis, and management

The Cardiovascular Autonomic Neuropathy (CAN) Subcommittee of the Toronto Consensus Panel on Diabetic Neuropathy worked to update CAN guidelines, with regard to epidemiology, clinical impact, diagnosis, usefulness of CAN testing, and management. CAN is the impairment of cardiovascular autonomic control in the setting of diabetes after exclusion of other causes. The prevalence of confirmed CAN is around 20%, and increases up to 65% with age and diabetes duration. Established risk factors for CAN are glycaemic control in type 1 and a combination of hypertension, dyslipidaemia, obesity, and glycaemic control in type 2 diabetes. CAN is a risk marker of mortality and cardiovascular morbidity, and possibly a progression promoter of diabetic nephropathy. Criteria for CAN diagnosis and staging are: (1) one abnormal cardiovagal test result identifies possible or early CAN; (2) at least two abnormal cardiovagal test results are required for definite or confirmed CAN; and (3) the presence of orthostatic hypotension in addition to abnormal heart rate test results identifies severe or advanced CAN. Progressive stages of CAN are associated with increasingly worse prognosis. CAN assessment is relevant in clinical practice for (1) diagnosis of CAN clinical forms, (2) detection and tailored treatment of CAN clinical correlates (e.g. tachycardia, orthostatic hypotension, non-dipping, QT interval prolongation), (3) risk stratification for diabetic complications and cardiovascular morbidity and mortality, and (4) modulation of targets of diabetes therapy. Evidence on the cost-effectiveness of CAN testing is lacking. Apart from the preventive role of intensive glycaemic control in type 1 diabetes, recommendations cannot be made for most therapeutic approaches to CAN.

Time course of changes in cerebral blood flow velocity after tourniquet deflation in patients with diabetes mellitus or previous stroke under sevoflurane anesthesia

We observed an increase in mean middle cerebral artery blood flow velocity (V(mca)) after tourniquet deflation during orthopedic surgery under sevoflurane anesthesia in patients with diabetes mellitus or previous stroke. Eight controls, seven insulin-treated diabetic patients, and eight previous stroke patients were studied. Arterial blood pressure, heart rate, V(mca), arterial blood gases, and plasma lactate levels were measured every minute for 10 min after tourniquet release in all patients. V(mca) was measured using a transcranial Doppler probe. V(mca) in all three groups increased after tourniquet deflation, the increase lasting for 4 or 5 min. However, the degree of increase in V(mca) in the diabetic patients was smaller than that in the other two groups after tourniquet deflation (at 2 min after tourniquet deflation: control 58.5 ± 3.3, previous stroke 58.4 ± 4.6, diabetes 51.7 ± 2.3; P < 0.05 compared with the other two groups). In conclusion, the degree of increase in V (mca) in diabetic patients is smaller than that in controls and patients with previous stroke.