Antisepsis protocol

Bjorn Johansson MD, PhD, FEBO

Chlorhexidine appears to be as effective as the more widely used povidone-iodine for preoperative antisepsis protocol in cataract surgery, according to a presentation at the 2015 Congress of the European Society of Ophthalmology (SOE) in Vienna, Austria.

“While the most widespread preoperative antisepsis protocol in use today includes povidone-iodine, the evidence suggests that chlorhexidine is equally effective. In case of hypersensitivity to or unavailability of one of the substances, the other formulation may be used. Most important of all, however, is to use a conjunctival antiseptic solution together with intracameral antibiotics,” said Bjorn Johansson MD, PhD, FEBO, Linkoping University, Sweden.

Quoting from the ESCRS Guidelines for Prevention and Treatment of Endophthalmitis Following Cataract Surgery, Dr Johansson said that “more than any other form of preoperative antisepsis, the literature supports the essential role of povidone-iodine for ocular surface preparation prior to cataract surgery”. However, he noted that the guidelines also state that “where povidone-iodine is contraindicated aqueous chlorhexidine 0.05 per cent may be used”.

Discussing the properties of the two compounds, Dr Johansson said that povidone-iodine reacts in electrophilic reactions with enzymes of the respiratory chain of the aerobic microorganisms, as well as with amino acids from the cell membrane proteins with less toxicity than other iodine formulations. Chlorhexidine, which was discovered in 1946 and first used in clinical practice in the 1950s, derives its effect by damaging outer cell layers and disrupting the cell membrane.

Known adverse effects of povidone-iodine include corneal injury, toxic anterior segment syndrome (TASS), rash, and anaphylactic shock. Its use is contraindicated in hyperthyreosis and iodine allergy. Side effects of chlorhexidine use include damage to the corneal endothelium, epithelial haze, urticaria, dyspnoea and anaphylactic shock, he said.

Looking at the evidence in the scientific literature, Dr Johansson cited a Cochrane report appraising the outcomes of nine randomised controlled trials which found moderate quality evidence supporting chlorhexidine over povidone-iodine for preoperative skin antisepsis to prevent surgical site infection, and that its use is associated with fewer positive skin culture results after application. Another study by Barkana et al concluded that povidone-iodine four per cent, ofloxacin 0.3 per cent or chlorhexidine 0.05 per cent may all be considered as viable options for a quick prophylaxis against infection.

After Dr Johansson’s own clinic changed its infection prophylaxis routines by first introducing intracameral cefuroxime injection, and soon thereafter changing the preoperative rinsing solution from physiological saline to chlorhexidine in 2002, there followed over 4,600 cataract surgeries without postoperative infection, he said.

Bjorn Johansson: bjorn.johansson@regionostergotland.se