Many hospitals are not complying with national guidelines for antibiotic prophylaxis in cardiac surgery, particularly those regarding the duration of antibiotic administration, according to the results of research published in the Medical Journal of Australia.

Dr Timothy Haydon, an intensivist at St Vincent's Hospital, Melbourne, and his co-authors conducted two point-prevalence surveys of intensive care units in 24 public and 27 private hospitals performing cardiac surgery in Australia in 2004 and 2008.

The surveys showed that the use of antibiotic prophylaxis protocols for cardiac surgery patients increased from 50 per cent of private hospitals in 2004 to 69 per cent in 2008, and from 58 per cent of public hospitals in 2004 to 87 per cent in 2008.

But compliance with Australian therapeutic guidelines for both drug choice and duration of administration was low, Dr Haydon said, with just 10 per cent and 12 per cent of all hospitals reporting full compliance for coronary artery graft surgery (CAGS) and 4 per cent and 8 per cent for valve surgery, in 2004 and 2008, respectively.

The research also found an increase in the administration of multiple classes of antibiotic rather than a single agent, with these agents being administered for surgical prophylaxis mostly as multiple doses over time rather than a single preoperative dose. This was accompanied by a substantial increase in the use of vancomycin in both isolated CAGS and in valve surgery with or without concurrent CAGS. The routine use of vancomycin is discouraged in the Australian guidelines.

"Concordance with the current Australian guidelines for antibiotic prophylaxis in cardiac surgery was found to be low … mainly due to the practice of ongoing postoperative administration of antibiotics in the intensive care unit," Dr Haydon said.

"Improving the evidentiary basis for the existing guidelines may require either standardised national epidemiological surveillance or a randomised study adequately powered to demonstrate the efficacy of single-dose preoperative versus prolonged perioperative cardiac surgical antibiotic prophylaxis."

In an accompanying editorial in the MJA, Clinical Professor Keryn Christiansen, from the University of Western Australia, writes that there have been a number of studies showing the relationship between timing of antibiotic administration and surgical site infections.

"As prophylaxis protocols improve patient outcomes, and adherence to local protocols in Australian cardiac surgery units seems to be high, it is timely to consider the optimum elements of such protocols in terms of timing of prophylaxis, duration of prophylaxis, and choice of agent," Dr Christiansen said.

The Medical Journal of Australia is a publication of the Australian Medical Association.

Source
Medical Journal of Australia