Skin preparation for preventing infection following caesarean section

Background
Surgical site infections are the third most frequently reported hospital- acquired infection. Women who give birth by caesarean section are exposed to the possibility of infection from their own, and external or environmental, sources of infection. Preventing infection by properly preparing the skin before incision is thus a vital part of the overall care given to women prior to caesarean birth. An antiseptic is applied to remove or reduce bacteria. These antiseptics include iodine or povidone-iodine, alcohol, chlorhexidine and parachlorometaxylenol and can be applied as liquids or powders, scrubs, paints, swabs or on impregnated drapes.

Review question
To compare the effects of different forms and methods of preoperative skin preparation for preventing postcaesarean infection.

Main findings
The available evidence from the randomised trials identified for this review (six trials involving 1522 women) is not sufficient to guide the best type of skin preparation for preventing wound or surgery site infection following caesarean section. When comparing different antiseptic procedures, one trial of chlorhexidine gluconate compared with iodine alone was associated with lower rates of bacterial growth after caesarean section; however, the quality of evidence for this outcome was judged to be of very low quality. No difference was found in wound infection (five trials) or uterine infection including of the lining (endometritis) (two trials).

Quality of the evidence and conclusions
The six included trials studied different forms, concentrations and methods of applying skin preparations for surgery. Of the six trials, two were reasonably large and the other four involved only small numbers of women. The overall quality of the evidence for wound infection was assessed as being low to very low for the different interventions.

More high-quality research about preparation is needed for women, particularly those at higher risk of surgical site infection, such as malnourished women, women with diabetes mellitus or obesity, or those who have an established infection before caesarean section.

Authors' conclusions: 

This review found that chlorhexidine gluconate compared with iodine alone was associated with lower rates of bacterial growth at 18 hours after caesarean section. However, this outcome was judged as very low quality of evidence. Little evidence is available from the included randomised controlled trials to evaluate different agent forms, concentrations and methods of skin preparation for preventing infection following caesarean section. Therefore, it is not yet clear what sort of skin preparation may be most efficient for preventing postcaesarean wound and surgical site infection.

There is a need for high-quality, properly designed randomised controlled trials with larger sample sizes in this field. High priority questions include comparing types of antiseptic (especially iodine versus chlorhexidine), the timing and duration of applying the antiseptic (especially previous night versus day of surgery, and application methods (scrubbing, swabbing and draping).

Read the full abstract...
Background: 

The risk of maternal mortality and morbidity (particularly postoperative infection) is higher for caesarean section than for vaginal birth. With the increasing rate of caesarean section, it is important that the risks to the mother are minimised as far as possible. This review focuses on different forms and methods for preoperative skin preparation to prevent infection.

Objectives: 

To compare the effects of different agent forms and methods of preoperative skin preparation for preventing postcaesarean infection.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (26 June 2014) and the reference lists of all included studies and review articles.

Selection criteria: 

Randomised and quasi-randomised trials, including cluster-randomised trials, evaluating any type of preoperative skin preparation agents, forms and methods of application for caesarean section.

Data collection and analysis: 

Three review authors independently assessed all potential studies for inclusion, assessed risk of bias and extracted the data using a predesigned form. Data were checked for accuracy.

Main results: 

We included six trials with a total of 1522 women. No difference was found in the primary outcomes of either wound infection or endometritis. Two trials of 1294 women, compared drape with no drape (one trial using iodine and the other using chlorhexidine) and found no significant difference in wound infection (risk ratio (RR) 1.29; 95% confidence interval (CI) 0.97 to 1.71). One trial of 79 women comparing alcohol scrub and iodophor drape with iodophor scrub without drape reported no wound infection in either group. One trial of 50 women comparing parachlorometaxylenol plus iodine with iodine alone reported no significant difference in wound infection (RR 0.33; 95% CI 0.04 to 2.99).

Two trials reported endometritis, one trial comparing alcohol scrub and iodophor drape with iodophor scrub only found no significant difference (RR 1.62; 95% CI 0.29 to 9.16). The other trial of 50 women comparing parachlorometaxylenol plus iodine with iodine alone reported no significant difference in endometritis (RR 0.88; 95% CI 0.56 to 1.38). One trial of 60 women comparing chlorhexidine gluconate with povidone-iodine reported significant lower rates of bacterial growth at 18 hours after caesarean section (RR 0.23, 95% CI 0.07 to 0.70). No difference was found in the secondary outcome of either length of stay or reduction of skin bacteria colony count. No trial reported other maternal outcomes, i.e. maternal mortality, repeat surgery and re-admission resulting from infection. One trial, which was only available as an abstract, investigated the effect of skin preparation on neonatal adverse events and found cord blood iodine concentration to be significantly higher in the iodine group.

Most of the risk of bias in the included studies was unclear in selection bias and attrition bias. The quality of the evidence using GRADE was low for wound infection comparing drape versus no drape, one-minute alcohol scrub with iodophor drape versus five-minute iodophor scrub without drape, and parachlorometaxylenol with iodine versus iodine alone. The quality of the evidence for wound infection comparing chlorhexidine gluconate with povidone-iodine was very low.

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