impossible to enroll participants

The purpose of this study is to determine whether perioperative use of Hartmann's solution in type II diabetes patients increases blood glucose level after surgery. The investigators expect the result to broaden the choice of fluid for diabetic patients and hopefully to diminish the side effects manifested by the excess use of normal saline.

Hyperglycemia is an independent risk factor for poor outcomes in diabetic patients experiencing sudden cardiac death, myocardial infarction, cerebrovascular accident. During surgery, activation of the neuroendocrine system by surgical stress releases stress-induced hormones such as cortisol, glucagon, epinephrine, and growth hormones and it leads to hepatic glucogenesis and glycogenolysis. Acute perioperative hyperglycemia induces decreased microvascular reactivity to dilatory agents like bradykinin, increased inflammatory cytokines, and impaired neutrophil activity. This impaired neuroendocrine and immune system leads to increased inflammation and multiple organ system dysfunction.

Thomas and Alberti showed postoperative use of 1 litre of Hartmann's solution was associated with a 7.5 mmol/L increase in plasma glucose concentrations, compared with an increase of 2.1 mmol/L in diabetic patients who received no intravenous fluids. Since then, normal saline has been preferred over Hartmann's solution in fear of acute hyperglycemia during postoperative period.

However, a recent review suggested that the maximum increase in glucose concentration with 1 L of Hartmann's solution would be about 1 mmol/L (about 18 mg/dL) ,with a much lower effect on blood glucose in clinical practice.

In fact, according to 2012 National Health Services (NHS) diabetes guideline for the perioperative management of the adult patient with diabetes, Hartmann's solution is used in preference to 0.9% saline. Excess use of normal saline could yield complications such as hyperglycemia and metabolic acidosis.

To date, a few studies have examined the effects of preoperative blood glucose levels on outcomes in patients undergoing surgery, and no prospective randomized investigations have been reported. The investigators are going to find out if Hartmann's solution actually raises postoperative glucose and insulin level by comparing two groups of diabetic patients using either Hartmann's solution or normal saline. The investigators expect the result to broaden the choice of fluid for diabetic patients undergoing surgery and hopefully to diminish the side effects manifested by the excess use of normal saline.

Inclusion Criteria:

• Type II diabetes patients who are included in American Society of Anesthesiologists Physical Status Classification I-III.

Exclusion Criteria:

• emergency surgery, acute or chronic kidney disease, electrolyte imbalance such as hypernatremia, hyponatremia, hyperkalemia or hypokalemia, liver dysfunction, unexpected hemodynamic instability due to excess bleeding, postoperative ventilatory care and trauma patients.