A total of 311 patients were recruited in the study. Out of which 11 were lost to follow up. So, outcome analysis was done on 300 patients(Fig 1).
In this study, we compared the efficacy of chlorhexidine-alcohol and povidone-iodine as skin antiseptic in prevention of SSI after CS. The baseline characteristics of the patients in both the groups are comparable such as age of the patients, period of gestations, BMI, number of days of hospital stay, level of hemoglobin (Table 1). The surgical characteristics in both the groups are comparable such as types of surgery whether elective or emergency, types of anesthesia, types of incision, duration of surgery, amount of blood loss, need for blood transfusion (Table 2).
Primary Outcome: The overall rate of SSI is 7%, chlorhexidine-alcohol group had 5.4% and povidone-iodine group had 8.6% shown in Table 3. Statistical analysis for the test of significance using Pearson Chi-Square gives p=0.271 which is statistically not significant.
Secondary outcome: Among Swab 1 there were growth of Enterococcus faecalis (2 in Group A and 1 in Group B), E.coli (1 in Group A) and P.aeruginosa (1 in Group B). In Swab 2, there was no growth of organism (Table 4). Among Swab 3 there were growth of E.coli in 2 patients in Group A and K.pneumoniae and Acinetobacter baumannii in group B (Table 5).
In this study, 7% (21 patients) of the study population developed SSI. In the chlorhexidine-alcohol group, the rate of SSI was 5.4% (8 patients) and in the povidone-iodine group, the rate of SSI was 8.6% (13 patients).
The rate of SSI in the study is close to that of the randomized controlled trial by Tuuli MG et al (2016)8 which was 4% in the chlorhexidine-alcohol group and 7.3% in the povidone-iodine group. The present study is also nearly similar to a systemic review and meta-analysis by Noorani A et al (2010)13 in clean-contaminated surgery where the rate of SSI was 6.1% in chlorhexidine-alcohol group and 9.8% in povidone-iodine group.
Some other studies have also shown a lower incidence of SSI in the chlorhexidine-alcohol group than povidone-iodine group in non gynaecological surgeries. Darouiche RO et al (2010)14 conducted a study in patients undergoing clean-contaminated surgery, in which the rate of SSI was 9.5% in chlorhexidine group and 16.1% in povidone-iodine group. In another prospective study conducted by Srinivas A et al (2015)15 in patients undergoing clean contaminated upper abdominal surgeries, the rate of SSI was 10.8% in chlorhexidine-alcohol group and 17.9% in povidone-iodine group.
However, there are studies which show the rate of SSI in both the chlorhexidine-alcohol group and povidone-iodine group were almost similar. In a randomized study by Menderes G et al (2012)16, the rate of SSI in CS were almost the same in both the chlorhexidine-alcohol and povidone-iodine groups being 5% and 5.8% respectively. Another randomized trial conducted by Ngai IM et al (2015)17 in preoperative skin preparation before Cesarean section, there was no significant difference in the rate of SSI in both the chlorhexidine-alcohol group and povidone-iodine groups being 4.5% and 4.6% respectively.
The CAPICA trial, May 2017 found that the rate of SSI in chlorhexidine-alcohol group and the PVI group was almost similar i.e., 6.3% and 7% respectively. It concluded that PVI should still be considered as appropriate antiseptic for Cesarean Section18.
In this study, organisms such as Enterococcus faecalis (2 in Group A and 1 in Group B), E.coli (1 in Group A) and P.aeruginosa (1 in Group B) are found in culture report of Swab 1. However, the culture report of the Swab 2 of these patients showed no growth of organism. This shows that chlorhexidine-alcohol is effective against Enterococcus faecalis and E.coli. It also shows that the routine use of povidone-iodine of skin preparation is effective.
The bacterial growth in Swab 3 were E.coli (2 in Group A), K. pneumoniae and Acinetobacter baumannii (1 in Group B as mixed growth). E.coli is the commonest bacteria responsible for SSI in this study being 9.5% of total SSI. This is similar to another study from India by Shahane V et al19 in which it was found that the commonest pathogen isolated in SSI was E.coli (31.25%) followed by P.aeruginosa (25%) and S.aureus (22%). The two patients whose wound swab showed growth of E.coli had no history of prolonged rupture of membrane, no history of multiple PV examination or positive urine cultures. Both patients underwent emergency Cesarean section for pathological CTG and placenta previa respectively. SSI is diagnosed during stitch removal on Day 7 and 8 respectively. Hence, the possibility of E.coli on culture could be from the ascending infection from genitourinary tract.
Most of the SSI (80.96%) developed after getting discharged from the hospital. They presented mostly with discharge from the wound, pain and swelling of the wound associated with or without fever. There was no need for readmission in any of the cases. But there was increased number of hospital visits for dressing and regular follow up. 19.04% of the SSI cases were diagnosed during hospital stay. Only 2 (9.52%) patients needed prolonged hospital stay. The average duration of hospital stay is 3-4 days.
19 patients (90.5%) developed superficial incisional SSI and 2 patients (9.5%) developed deep incisional SSI (Table 3). There was no organ/space SSI in both the groups in this study .Resuturing was done for one patient (4.76%) with deep incisional SSI for which she needed prolonged hospital stay for 19 days. All other patients with SSI were healed by secondary intention.
Prolonged leakage of membrane and number of PV examination also affects the post operative morbidity after Cesarean section20–22. In our study, 2 patients who developed SSI had preterm premature rupture of membrane, the duration of rupture of membrane was >18 hours. Another 2 had term premature rupture of membrane with duration of membrane > 18 hours. Thus, 4 patients (19.06%) of those who developed SSI had prolonged rupture of membrane. The mean number of PV examination in both the groups are similar.
The strength of the study is that it is a prospective randomized controlled trial in a tertiary care institute and swabs from the incision site were taken before and after application of antiseptics. However, the limitation of the study is that it has a relatively small sample size.