Hyperglycaemia increases postsurgical infection

THE LANCET

Hyperglycaemia increases postsurgical infection

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yperglycaemic patients, with or without diabetes, may be at increased risk for postsurgical wound infection, researchers from the Cleveland Clinic Foundation (Ohio, USA) reported at the American Society of Anesthesiologists’ meeting in New Orleans (Oct 19-23). “We finally have a large human study that supports what many of us have long suspected, namely that poor glucose control following surgery can interfere with wound healing”, said lead

investigator Lee Wallace. “Although this is particularly true for diabetics, our findings strongly suggest that hyperglycaemia may also place nondiabetics at increased risk.” T h e investigators analysed the records of 4514 coronary artery bypass graft (CABG) patients who had blood glucose values measured on admission to the cardiac intensive care unit after surgery. Insulindependent diabetics, non-insulindependent diabetics, and nondiabetics who were hyperglycaemic had a higher incidence of mediastinitis or wound infection than those who were not hyperglycaemic, said Wallace. Hyperglycaemia following CABG was associated with a “three to five fold increase” in the incidence of postsurgical infection in nondiabetics and diabetics (0.4% in the group of patients with a blood glucose of less than 11.1 mmoVL, 1.8% in the group with values greater than 11.1 m m o l ) . “We don’t know yet whether elevated preoperative blood glucose levels are also a risk factor, or whether they are overshadowed by the effects of intraoperative or postoperative hyperglycemia.” Commenting on the findings, Wallace said that “in-vitro evidence and putative evidence in humans suggests that hyperglycaemia may trigger abnormalities in leukocyte and complement function which contribute to a reduction in immunity. Cardiac surgery patients are particularly at risk because of what we do to them. The results suggest that tight glucose control is warranted in all patients following major surgery”, he added. Marilynn Larkin

Orange is good for health of hunters

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ew York State health officials report that between 1989 and 1995, hunters shot colleagues in the field 508 times ( M M W R 1996; 45: 884-87). Only 8% of these events were fatal and most people were shot at close range; 356 incidents involved two parties-in just over half of these, the victims acquired the bullet within 50 yards of the person firing the shot. Unintentional discharge of the weapon was the cause of only 11% of these injuries-in 35% of cases the victim was mistaken for game. Although the New York State began promoting firearms safety 1158

courses in 1992, and began encouraging hunters to wear orange at the same time, the state does not require hunters to wear fluorescent or international orange to improve visibility. 76% of the people injured in twoparty incidents between 1989 and 1995 were not wearing orange. However, from 1992 to 1995 the average annual injury rate fell by 27% compared with that reported between 1988 and 1991. So maybe the health advantages of orange(s) are getting through to US hunters. David H Frankel

Vent ricuIa r premat ure beats and caffeine

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affeine restriction does not reduce the frequency of ventricular premature beats (VPBs) in otherwise well patients, report David Newby and colleagues (Edinburgh,

UK) .

Caffeine, a methyl xanthine, has been implicated as a cause of VPBs when given to caffeine-naive individuals but this finding has not been consistently confirmed during chronic moderate use-even in patients with serious arrhythmias or ischaemic heart disease. After excluding patients with past or present evidence of hypertensive or cardiac disease, or metabolic disorders (raised glucose, cholesterol, or abnormal thyroid tests), 13 otherwise well patients with VPBs were enrolled in a 6-week double-blind intervention study (Heart 1996; 76: 355-57). Patients had weekly 24-hour electrocardiographic monitoring and also self-graded their palpitations on a visual analogue scale. After a 2-week baseline period, patients were randomised to drink at least three cups of caffeinated or decaffeinated instant coffee on alternate weeks for the next 2 weeks while still following their usual diet. During the final 2 weeks of the trial patients followed a caffeine-free diet and continued to consume the caffeinated or decaffeinated instant coffee on a double-blind basis. Patient compliance with the diet was confirmed by measurement of serum caffeine concentrations. These were significantly different during caffeine and decaffeinated coffee supplemented weeks. A mean number of 427 VPBs per day was recorded during the baseline period and this did not change significantly during caffeine-supplemented or caffeine-free weeks. There was a good correlation between the visual analogue palpitation scores and the 24-hour electrocardiogram results. The authors, who note that arrhythmogenic effects of caffeine have been found at only supraphysiological concentrations, suggest that caffeine restriction will not benefit most patients with symptomatic idiopathic VPBs. However, they also suggest the possibility that the patients enrolled in the study may already have been referrals who were caffeine resistant. K D Hopkins

Vol348 * October 26, 1996