infection control & hospital epidemiology
august 2015, vol. 36, no. 8
original article
Practices to Reduce Surgical Site Infections Among Women Undergoing Cesarean Section: A Review Rebeccah A. McKibben, MPH;1 Samantha I. Pitts, MD;1 Catalina Suarez-Cuervo, MD;2 Trish M. Perl, MD, MSc;1,2 Eric B. Bass, MD1,2
objective. Surgical site infections (SSIs) are a leading cause of morbidity and mortality among women undergoing cesarean section (C-section), a common procedure in North America. While risk factors for SSI are often modifiable, wide variation in clinical practice exists. With this review, we provide a comprehensive overview of the results and quality of systematic reviews and meta-analyses on interventions to reduce surgical site infections among women undergoing C-section. methods. We searched PubMed and the Cochrane Database of Systematic Reviews for systematic reviews and meta-analyses published between January 2000 and May 2014 on interventions to reduce the occurrence of SSIs (incisional infections and endometritis), among women undergoing C-section. We extracted data on the interventions, outcomes, and strength of evidence as determined by the original article authors, and assessed the quality of each article based on a modified Assessment of Multiple Systematic Reviews tool. results. A total of 30 review articles met inclusion criteria and were reviewed. Among these articles, 77 distinct interventions were evaluated: 29% were supported with strong evidence as assessed by the original article authors, and 83% of the reviews articles were classified as good quality based on our assessment. Ten interventions were classified as being effective in reducing SSI with strong evidence in a good-quality article, including preoperative vaginal cleansing, the use of perioperative antibiotic prophylaxis, and several surgical techniques. conclusion. Efforts to reduce SSI rates among women undergoing C-section should include interventions such as preoperative vaginal cleansing and the use of perioperative antibiotics because compelling evidence exists to support their effectiveness. Infect Control Hosp Epidemiol 2 01 5; 3 6( 8) :9 1 5– 9 21
Almost 30% of births in the developed world are by cesarean section (C-section), making this an extremely common procedure performed in almost every hospital.1 Surgical site infections (SSIs), including both incisional infection and endometritis, are a leading cause of morbidity following C-section.2–4 This procedure is associated with increased mortality, higher rehospitalization rate, longer length of stay, and greater healthcare costs.5–9 The rate of SSI following C-section ranges from 3% to 15%, depending on the surveillance method and patient population.10 According to the 2009 National Healthcare Safety Network (NHSN) report, the pooled risk-adjusted mean rates of SSI after C-section from 2006 to 2008 were 1.5%, 2.4%, and 3.8%, depending on the presence and number of risk factors.11 Clinical trials have revealed ways to reduce SSI rates after C-section based on the risk factors for developing an SSI; many SSIs are preventable with proper perioperative preparation and surgical technique.12–17 However, wide variation in clinical practice exists because techniques employed in C-section
often depend on the clinical situation and the surgeon’s preference.18 A comprehensive synthesis based on evidencebased techniques will help to increase the consistency and frequency with which clinicians employ best practices to reduce SSI after C-section.19 In this analysis, we systematically reviewed the results and quality of systematic reviews and meta-analyses regarding the impact of practices designed to reduce SSI rates among women undergoing C-section. These findings highlight strategies that provide a strong evidence base for reducing SSIs after C-section.
methods The protocol for our systematic review was based on the Methods Guide for Effectiveness and Comparative Effectiveness Reviews from the Agency for Healthcare Research and Quality (AHRQ).20 The analytic framework of this review is shown in Figure 1.
Affiliations: 1. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; 2. Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland. Received March 12, 2015; accepted April 28, 2015; electronically published May 20, 2015 © 2015 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2015/3608-0007. DOI: 10.1017/ice.2015.116
916
infection control & hospital epidemiology
figure 1.
august 2015, vol. 36, no. 8
Analytic framework for systematic review.
Data Sources and Selection Two members of our study team searched PubMed and the Cochrane Database of Systematic Reviews for systematic reviews and meta-analyses of interventions to reduce the rate of SSIs among women undergoing C-section in the United States, as either a primary or secondary outcome. We used the Center for Disease Control’s NHSN’s definition of SSI, which is stratified by superficial incisional SSI, deep incisional SSI, and organ/space SSI.21 To review the most recent data, the study search was limited to English-language articles published between January 1, 2000, and May 1, 2014. Eligible comparators included placebo, no treatment, or standard of care. We included reviews of women undergoing C-section among other surgical populations if the data were separately identifiable. The reviewers screened articles identified in our search by title and abstract for subsequent full-text review of eligibility, and reference lists of pertinent systematic reviews or metaanalyses were used to identify additional reports. We did not
attempt to identify unpublished articles or contact study authors. The full PubMed search strategy is shown in Table 1. Data Extraction and Quality Assessment Two reviewers independently extracted data from the included review articles (ie, including the interventions, outcomes, and strength of evidence) and independently assessed the quality of the reviews using standardized data collection tools. The quality of included reviews was determined using a modified version of the Assessment of Multiple Systematic Reviews (AMSTAR) tool.22 Modifications to the AMSTAR tool were made to clarify the quality assessment criteria and standardize the analysis (Table 2). A third party resolved discrepancies between the 2 reviewers to reach a decision that all 3 authors endorsed. The reviewers classified the strength of evidence as “strong” or “weak” based on the conclusions by the authors of the original article, taking into account the original authors’
surgical site infections in cesarean sections
assessment of the amount of evidence, sample sizes, study designs, and potential risk of bias in the studies. The quality assessment criteria from the modified AMSTAR tool were classified as either “major” or “minor.” The 4 major quality assessment criteria included duplicate data extraction (criterion 2b), a literature search performed on at least 2 databases (criterion 3), a list of included studies (criterion 5a), and the rating and documentation of the scientific quality of included studies (criterion 7). The other 8 criteria in the modified AMSTAR tool were classified as minor quality assessment criteria. table 1.
PubMed Search Strategy
Search
String
1 2 3 4 5 6 7 8 9 10 11 12
“wound infection”[mh] “wound infection [tiab] “surgical wound infection”[mh] “surgical wound infection”[tiab] “obstetric infection”[tiab] “surgical site infection”[tiab] #1 OR #2 OR #3 OR #4 OR #5 OR #6 cesarean delivery[tiab] cesarean section[mh] cesarean section[tiab] #8 OR #9 OR #10 #7 AND #11
NOTE.
No. of Results
mh, mesh; tiab, title and abstract.
table 2.
37,094 12,663 28,241 640 13 2,625 45,558 6,630 35,066 19,156 10,960 908
917
To determine whether a review met the minor quality assessment criteria regarding characteristics of the included studies (study design [6a], intervention [6c], comparison group [6d], and outcome [6e]), we used the following system: “yes” if all included studies in the review satisfied the criterion; “some” if at least 1, but not all, studies in the review satisfied the criterion; and “no” if none of the included studies satisfied the criterion. When determining whether a review met the minor quality assessment criterion concerning the population of the included studies (criterion 6b), we used the following system: “yes” if most included studies reported ≥2 of 3 population variables (eg, age, elective vs emergency C-section, and primary vs repeat C-section); “some” if at least 1 study, but not all, reported >1 of the population variables; and “no” if none of the included studies reported >1 of the population variables. When determining whether a review met the minor quality assessment criteria regarding grading the strength of evidence of the included studies (criterion 9), we used the following system: “yes” if the grading addressed the risk of bias, consistency, directness, and precision of evidence; “some” if the grading addressed only 3 of those 4 domains of the evidence; and “no” if the grading addressed 1 major criteria and 2 cm, and cord traction for placenta delivery. Surprisingly, no systematic reviews among women undergoing C-section have addressed the effectiveness of hair removal or skin preparation in reducing SSIs, although these interventions have been assessed in other surgical populations.46,47 While the majority of review articles included in this analysis were of good quality, only ~50% of the interventions from good-quality articles had strong strength of evidence of effectiveness as assessed by the original authors of the article, suggesting the need for robust studies on the safety and effectiveness of pre-, intra- and postoperative interventions to reduce SSIs. Our review has important strengths and limitations. Given the variation in practice and opinions, importantly, 2 independent reviewers identified reviews for inclusion, extracted data, and performed quality assessment analyses, which minimized the risk of bias. Our protocol was based on the Methods Guide published by AHRQ, and we used a modified AMSTAR tool for quality assessment, both of which are well-validated tools for analysis.20,22 Our study was limited by the fact that all included reviews were published in English, and we only included interventions that had been assessed in North America, so our findings may not be generalizable to the global community. However, this decision was based on the desire to assess interventions that have
920
infection control & hospital epidemiology
august 2015, vol. 36, no. 8
been implemented in North American populations and to formulate recommendations that are relevant to these populations. We limited our study search to PubMed and the Cochrane Database for Systematic Reviews because those are the best sources for identifying systematic reviews. Although we did not search other databases or look for nonpublished literature, it is unlikely that we missed a high-quality systematic review of the topic. Lastly, we did not assess the clinical heterogeneity of the studies included in the reviews, or the impact that varying study designs may have had on the outcomes measured. Efforts to reduce SSI rates among women undergoing C-section should use interventions supported by compelling evidence of their effectiveness in high-quality studies, including preoperative vaginal cleansing and the use of perioperative prophylactic antibiotics. This study also highlights the need for further research on the effectiveness of other techniques to reduce SSI rates among women undergoing C-section, particularly on the timing of prophylactic antibiotic administration, intraoperative surgical techniques, and postoperative wound care. Cesarean deliveries are among the most common surgical procedures in the United States, with more than 1 million procedures performed each year.48 These procedures offer a unique surgical challenge, as obstetricians must strive to reduce the risks for both mother and child. Because of the desire to choose the physician and time of delivery, the frequency of C-section births is increasing in this otherwise healthy population. Hence, there is an obligation to balance patient desires with evidence-based techniques to reduce SSI rates in this population of women and for physicians to employ best practices to protect the safety of mothers and neonates.
a ck n ow le d g m e n t Financial support. No financial support was provided relevant to this article. Potential conflict of interest. All authors report no conflict of interest relevant to this article. Address correspondence to Rebeccah A. McKibben, MPH, 624 North Broadway, Room 680A, Baltimore, MD, 21205 ([email protected]).
s u p p le m e n ta ry m a t e r ia l To view supplementary material for this article, please visit http://dx.doi.org/ 10.1017/ice.2015.116
references 1. Osterman MJ, Martin JA. Trends in low-risk cesarean delivery in the United States, 1990–2013. National Vital Statistics Report Atlanta, GA: Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System 2014;63:1–16. 2. Brown HL. Informing the patient and the community about the implications of primary cesarean. Semin Perinatol 2012;36: 403–406.
3. Liu S, Liston RM, Joseph KS, et al. Maternal mortality and severe morbidity associated with low-risk planned cesarean delivery versus planned vaginal delivery at term. CMAJ 2007;176:455–460. 4. Hillan EM. Postoperative morbidity following Caesarean delivery. J Adv Nurs 1995;22:1035–1042. 5. Deneux-Tharaux C, Carmona E, Bouvier-Colle MH, Breart G. Postpartum maternal mortality and cesarean delivery. Obstet Gynecol 2006;108:541–548. 6. Herwaldt LA, Cullen JJ, Scholz D, et al. A prospective study of outcomes, healthcare resource utilization, and costs associated with postoperative nosocomial infections. Infect Control Hosp Epidemiol 2006;27:1291–1298. 7. Kirkland KB, Briggs JP, Trivette SL, Wilkinson WE, Sexton DJ. The impact of surgical-site infections in the 1990s: attributable mortality, excess length of hospitalization, and extra costs. Infect Control Hosp Epidemiol 1999;20:725–730. 8. Lydon-Rochelle M, Holt VL, Martin DP, Easterling TR. Association between method of delivery and maternal rehospitalization. JAMA 2000;283:2411–2416. 9. Olsen MA, Butler AM, Willers DM, Gross GA, Hamilton BH, Fraser VJ. Attributable costs of surgical site infection and endometritis after low transverse cesarean delivery. Infect Control Hosp Epidemiol 2010;31:276–282. 10. Olsen MA, Butler AM, Willers DM, Devkota P, Gross GA, Fraser VJ. Risk factors for surgical site infection after low transverse cesarean section. Infect Control Hosp Epidemiol 2008;29: 477–484; discussion 485–476. 11. Edwards JR, Peterson KD, Mu Y, et al. National Healthcare Safety Network (NHSN) report: data summary for 2006 through 2008, issued December 2009. Am J Infect Control 2009;37: 783–805. 12. Alanis MC, Villers MS, Law TL, Steadman EM, Robinson CJ. Complications of cesarean delivery in the massively obese parturient. Am J Obstet Gynecol 2010;203(271):e271–e277. 13. Dempsey JC, Ashiny Z, Qiu CF, Miller RS, Sorensen TK, Williams MA. Maternal pre-pregnancy overweight status and obesity as risk factors for cesarean delivery. J Maternal Fetal Neonat Med 2005;17:179–185. 14. Killian CA, Graffunder EM, Vinciguerra TJ, Venezia RA. Risk factors for surgical-site infections following cesarean section. Infect Control Hosp Epidemiol 2001;22:613–617. 15. Myles TD, Gooch J, Santolaya J. Obesity as an independent risk factor for infectious morbidity in patients who undergo cesarean delivery. Obstet Gynecol 2002;100:959–964. 16. Schneid-Kofman N, Sheiner E, Levy A, Holcberg G. Risk factors for wound infection following cesarean deliveries. Int J Gynecol Obstet 2005;90:10–15. 17. Tran TS, Jamulitrat S, Chongsuvivatwong V, Geater A. Risk factors for postcesarean surgical site infection. Obstet Gynecol 2000;95:367–371. 18. Dahlke JD, Mendez-Figueroa H, Rouse DJ, Berghella V, Baxter JK, Chauhan SP. Evidence-based surgery for cesarean delivery: an updated systematic review. Am J Obstet Gynecol 2013;209: 294–306. 19. Hofmeyr JG, Novikova N, Mathai M, Shah A. Techniques for cesarean section. Am J Obstet Gynecol 2009;201(5):431–444. 20. Agency for Healthcare Research and Quality. Methods Guide for Effectiveness and Comparative Effectiveness Reviews. Rockville, MD: Agency for Healthcare Research and Quality (US), 2008.
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21. Horan TC, Andrus M, Dudeck MA. CDC/NHSN surveillance definition of health care–associated infection and criteria for specific types of infections in the acute care setting. Am J Infect Control 2008;36:309–332. 22. White CM, Ip S, McPheeters M, et al. Using existing systematic reviews to replace de novo processes in conducting comparative effectiveness reviews. Methods Guide for Effectiveness and Comparative Effectiveness Reviews. Rockville, MD: Agency for Healthcare Research and Quality (US), 2008. 23. Haas DM, Morgan Al Darei S, Contreras K. Vaginal preparation with antiseptic solution before cesarean section for preventing postoperative infections. Cochrane Database Syst Revs 2010;3: CD007892. 24. Smaill FM, Gyte GM. Antibiotic prophylaxis versus no prophylaxis for preventing infection after cesarean section. Cochrane Database Syst Revs 2010;1:CD007482. 25. Alfirevic Z, Gyte GM, Dou L. Different classes of antibiotics given to women routinely for preventing infection at caesarean section. Cochrane Database Syst Revs 2010;10:CD008726. 26. Tita AT, Rouse DJ, Blackwell S, Saade GR, Spong CY, Andrews WW. Emerging concepts in antibiotic prophylaxis for cesarean delivery: a systematic review. Obstet Gynecol 2009;113:675–682. 27. Costantine MM, Rahman M, Ghulmiyah L, et al. Timing of perioperative antibiotics for cesarean delivery: a metaanalysis. Am J Obstet Gynecol 2008;199(301):e301–e306. 28. Tooher R, Gates S, Dowswell T, Davis LJ. Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period. Cochrane Database Syst Revs 2010;5:CD001689. 29. Mathai M, Hofmeyr GJ. Abdominal surgical incisions for caesarean section. Cochrane Database Syst Revs 2007;1: CD004453. 30. Altman AD, Allen VM, McNeil SA, Dempster J. Pfannenstiel incision closure: a review of current skin closure techniques. JOGC 2009;31:514–520. 31. Tuuli MG, Rampersad RM, Carbone JF, Stamilio D, Macones GA, Odibo AO. Staples compared with subcuticular suture for skin closure after cesarean delivery: a systematic review and metaanalysis. Obstet Gynecol 2011;117:682–690. 32. Dodd JM, Anderson ER, Gates S. Surgical techniques for uterine incision and uterine closure at the time of caesarean section. Cochrane Database Syst Revs 2008;3:CD004732. 33. Jacobs-Jokhan D, Hofmeyr G. Extra-abdominal versus intraabdominal repair of the uterine incision at caesarean section. Cochrane Database Syst Revs 2004;4:CD000085.
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34. Anderson ER, Gates S. Techniques and materials for closure of the abdominal wall in caesarean section. Cochrane Database Syst Revs 2004;4:CD004663. 35. Chelmow D, Rodriguez EJ, Sabatini MM. Suture closure of subcutaneous fat and wound disruption after cesarean delivery: a meta-analysis. Obstet Gynecol 2004;103:974–980. 36. Hellums EK, Lin MG, Ramsey PS. Prophylactic subcutaneous drainage for prevention of wound complications after cesarean delivery—a metaanalysis. Am J Obstet Gynecol 2007;197(3):229–235. 37. Anorlu RI, Maholwana B, Hofmeyr GJ. Methods of delivering the placenta at caesarean section. Cochrane Database Syst Revs 2008;3: CD004737. 38. Bamigboye AA, Hofmeyr GJ. Non-closure of peritoneal surfaces at caesarean section—a systematic review. S Afr Med J 2005; 95(2):123–126. 39. Berghella V, Baxter JK, Chauhan SP. Evidence-based surgery for cesarean delivery. Am J Obstet Gynecol 2005;193(5):1607–1617. 40. Gates S, Anderson ER. Wound drainage for caesarean section. Cochrane Database Syst Revs 2013;12:CD004549. 41. Hadiati DR, Hakimi M, Nurdiati DS. Skin preparation for preventing infection following caesarean section. Cochrane Database Syst Revs 2012;9:CD007462. 42. Liabsuetrakul T, Peeyananjarassri K. Mechanical dilatation of the cervix at non-labour caesarean section for reducing postoperative morbidity. Cochrane Database Syst Revs 2011;11:CD008019. 43. Chelmow D, Ruehli MS, Huang E. Prophylactic use of antibiotics for nonlaboring patients undergoing cesarean delivery with intact membranes: a meta-analysis. Am J Obstet Gynecol 2001; 184:656–661. 44. Clay FS, Walsh CA, Walsh SR. Staples vs subcuticular sutures for skin closure at cesarean delivery: a metaanalysis of randomized controlled trials. Am J Obstet Gynecol Am J 2011;204:378–383. 45. Mackeen AD, Berghella V, Larsen ML. Techniques and materials for skin closure in caesarean section. Cochrane Database Syst Revs 2012;11:CD003577. 46. Webster J, Osborne S. Preoperative bathing or showering with skin antiseptics to prevent surgical site infection. Cochrane Database Syst Revs 2012;9:CD004985. 47. Tanner J, Woodings D, Moncaster K. Preoperative hair removal to reduce surgical site infection. Cochrane Database Syst Revs 2006:CD004122. 48. Hall MJ, DeFrances CJ, Williams SN, Golosinskiy A, Schwartzman A. National Hospital Discharge Survey: 2007 summary. Nat Health Stat Repts 2010:1–20; 24.
august 2015, vol. 36, no. 8
original article
Practices to Reduce Surgical Site Infections Among Women Undergoing Cesarean Section: A Review Rebeccah A. McKibben, MPH;1 Samantha I. Pitts, MD;1 Catalina Suarez-Cuervo, MD;2 Trish M. Perl, MD, MSc;1,2 Eric B. Bass, MD1,2
objective. Surgical site infections (SSIs) are a leading cause of morbidity and mortality among women undergoing cesarean section (C-section), a common procedure in North America. While risk factors for SSI are often modifiable, wide variation in clinical practice exists. With this review, we provide a comprehensive overview of the results and quality of systematic reviews and meta-analyses on interventions to reduce surgical site infections among women undergoing C-section. methods. We searched PubMed and the Cochrane Database of Systematic Reviews for systematic reviews and meta-analyses published between January 2000 and May 2014 on interventions to reduce the occurrence of SSIs (incisional infections and endometritis), among women undergoing C-section. We extracted data on the interventions, outcomes, and strength of evidence as determined by the original article authors, and assessed the quality of each article based on a modified Assessment of Multiple Systematic Reviews tool. results. A total of 30 review articles met inclusion criteria and were reviewed. Among these articles, 77 distinct interventions were evaluated: 29% were supported with strong evidence as assessed by the original article authors, and 83% of the reviews articles were classified as good quality based on our assessment. Ten interventions were classified as being effective in reducing SSI with strong evidence in a good-quality article, including preoperative vaginal cleansing, the use of perioperative antibiotic prophylaxis, and several surgical techniques. conclusion. Efforts to reduce SSI rates among women undergoing C-section should include interventions such as preoperative vaginal cleansing and the use of perioperative antibiotics because compelling evidence exists to support their effectiveness. Infect Control Hosp Epidemiol 2 01 5; 3 6( 8) :9 1 5– 9 21
Almost 30% of births in the developed world are by cesarean section (C-section), making this an extremely common procedure performed in almost every hospital.1 Surgical site infections (SSIs), including both incisional infection and endometritis, are a leading cause of morbidity following C-section.2–4 This procedure is associated with increased mortality, higher rehospitalization rate, longer length of stay, and greater healthcare costs.5–9 The rate of SSI following C-section ranges from 3% to 15%, depending on the surveillance method and patient population.10 According to the 2009 National Healthcare Safety Network (NHSN) report, the pooled risk-adjusted mean rates of SSI after C-section from 2006 to 2008 were 1.5%, 2.4%, and 3.8%, depending on the presence and number of risk factors.11 Clinical trials have revealed ways to reduce SSI rates after C-section based on the risk factors for developing an SSI; many SSIs are preventable with proper perioperative preparation and surgical technique.12–17 However, wide variation in clinical practice exists because techniques employed in C-section
often depend on the clinical situation and the surgeon’s preference.18 A comprehensive synthesis based on evidencebased techniques will help to increase the consistency and frequency with which clinicians employ best practices to reduce SSI after C-section.19 In this analysis, we systematically reviewed the results and quality of systematic reviews and meta-analyses regarding the impact of practices designed to reduce SSI rates among women undergoing C-section. These findings highlight strategies that provide a strong evidence base for reducing SSIs after C-section.
methods The protocol for our systematic review was based on the Methods Guide for Effectiveness and Comparative Effectiveness Reviews from the Agency for Healthcare Research and Quality (AHRQ).20 The analytic framework of this review is shown in Figure 1.
Affiliations: 1. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; 2. Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland. Received March 12, 2015; accepted April 28, 2015; electronically published May 20, 2015 © 2015 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2015/3608-0007. DOI: 10.1017/ice.2015.116
916
infection control & hospital epidemiology
figure 1.
august 2015, vol. 36, no. 8
Analytic framework for systematic review.
Data Sources and Selection Two members of our study team searched PubMed and the Cochrane Database of Systematic Reviews for systematic reviews and meta-analyses of interventions to reduce the rate of SSIs among women undergoing C-section in the United States, as either a primary or secondary outcome. We used the Center for Disease Control’s NHSN’s definition of SSI, which is stratified by superficial incisional SSI, deep incisional SSI, and organ/space SSI.21 To review the most recent data, the study search was limited to English-language articles published between January 1, 2000, and May 1, 2014. Eligible comparators included placebo, no treatment, or standard of care. We included reviews of women undergoing C-section among other surgical populations if the data were separately identifiable. The reviewers screened articles identified in our search by title and abstract for subsequent full-text review of eligibility, and reference lists of pertinent systematic reviews or metaanalyses were used to identify additional reports. We did not
attempt to identify unpublished articles or contact study authors. The full PubMed search strategy is shown in Table 1. Data Extraction and Quality Assessment Two reviewers independently extracted data from the included review articles (ie, including the interventions, outcomes, and strength of evidence) and independently assessed the quality of the reviews using standardized data collection tools. The quality of included reviews was determined using a modified version of the Assessment of Multiple Systematic Reviews (AMSTAR) tool.22 Modifications to the AMSTAR tool were made to clarify the quality assessment criteria and standardize the analysis (Table 2). A third party resolved discrepancies between the 2 reviewers to reach a decision that all 3 authors endorsed. The reviewers classified the strength of evidence as “strong” or “weak” based on the conclusions by the authors of the original article, taking into account the original authors’
surgical site infections in cesarean sections
assessment of the amount of evidence, sample sizes, study designs, and potential risk of bias in the studies. The quality assessment criteria from the modified AMSTAR tool were classified as either “major” or “minor.” The 4 major quality assessment criteria included duplicate data extraction (criterion 2b), a literature search performed on at least 2 databases (criterion 3), a list of included studies (criterion 5a), and the rating and documentation of the scientific quality of included studies (criterion 7). The other 8 criteria in the modified AMSTAR tool were classified as minor quality assessment criteria. table 1.
PubMed Search Strategy
Search
String
1 2 3 4 5 6 7 8 9 10 11 12
“wound infection”[mh] “wound infection [tiab] “surgical wound infection”[mh] “surgical wound infection”[tiab] “obstetric infection”[tiab] “surgical site infection”[tiab] #1 OR #2 OR #3 OR #4 OR #5 OR #6 cesarean delivery[tiab] cesarean section[mh] cesarean section[tiab] #8 OR #9 OR #10 #7 AND #11
NOTE.
No. of Results
mh, mesh; tiab, title and abstract.
table 2.
37,094 12,663 28,241 640 13 2,625 45,558 6,630 35,066 19,156 10,960 908
917
To determine whether a review met the minor quality assessment criteria regarding characteristics of the included studies (study design [6a], intervention [6c], comparison group [6d], and outcome [6e]), we used the following system: “yes” if all included studies in the review satisfied the criterion; “some” if at least 1, but not all, studies in the review satisfied the criterion; and “no” if none of the included studies satisfied the criterion. When determining whether a review met the minor quality assessment criterion concerning the population of the included studies (criterion 6b), we used the following system: “yes” if most included studies reported ≥2 of 3 population variables (eg, age, elective vs emergency C-section, and primary vs repeat C-section); “some” if at least 1 study, but not all, reported >1 of the population variables; and “no” if none of the included studies reported >1 of the population variables. When determining whether a review met the minor quality assessment criteria regarding grading the strength of evidence of the included studies (criterion 9), we used the following system: “yes” if the grading addressed the risk of bias, consistency, directness, and precision of evidence; “some” if the grading addressed only 3 of those 4 domains of the evidence; and “no” if the grading addressed 1 major criteria and 2 cm, and cord traction for placenta delivery. Surprisingly, no systematic reviews among women undergoing C-section have addressed the effectiveness of hair removal or skin preparation in reducing SSIs, although these interventions have been assessed in other surgical populations.46,47 While the majority of review articles included in this analysis were of good quality, only ~50% of the interventions from good-quality articles had strong strength of evidence of effectiveness as assessed by the original authors of the article, suggesting the need for robust studies on the safety and effectiveness of pre-, intra- and postoperative interventions to reduce SSIs. Our review has important strengths and limitations. Given the variation in practice and opinions, importantly, 2 independent reviewers identified reviews for inclusion, extracted data, and performed quality assessment analyses, which minimized the risk of bias. Our protocol was based on the Methods Guide published by AHRQ, and we used a modified AMSTAR tool for quality assessment, both of which are well-validated tools for analysis.20,22 Our study was limited by the fact that all included reviews were published in English, and we only included interventions that had been assessed in North America, so our findings may not be generalizable to the global community. However, this decision was based on the desire to assess interventions that have
920
infection control & hospital epidemiology
august 2015, vol. 36, no. 8
been implemented in North American populations and to formulate recommendations that are relevant to these populations. We limited our study search to PubMed and the Cochrane Database for Systematic Reviews because those are the best sources for identifying systematic reviews. Although we did not search other databases or look for nonpublished literature, it is unlikely that we missed a high-quality systematic review of the topic. Lastly, we did not assess the clinical heterogeneity of the studies included in the reviews, or the impact that varying study designs may have had on the outcomes measured. Efforts to reduce SSI rates among women undergoing C-section should use interventions supported by compelling evidence of their effectiveness in high-quality studies, including preoperative vaginal cleansing and the use of perioperative prophylactic antibiotics. This study also highlights the need for further research on the effectiveness of other techniques to reduce SSI rates among women undergoing C-section, particularly on the timing of prophylactic antibiotic administration, intraoperative surgical techniques, and postoperative wound care. Cesarean deliveries are among the most common surgical procedures in the United States, with more than 1 million procedures performed each year.48 These procedures offer a unique surgical challenge, as obstetricians must strive to reduce the risks for both mother and child. Because of the desire to choose the physician and time of delivery, the frequency of C-section births is increasing in this otherwise healthy population. Hence, there is an obligation to balance patient desires with evidence-based techniques to reduce SSI rates in this population of women and for physicians to employ best practices to protect the safety of mothers and neonates.
a ck n ow le d g m e n t Financial support. No financial support was provided relevant to this article. Potential conflict of interest. All authors report no conflict of interest relevant to this article. Address correspondence to Rebeccah A. McKibben, MPH, 624 North Broadway, Room 680A, Baltimore, MD, 21205 ([email protected]).
s u p p le m e n ta ry m a t e r ia l To view supplementary material for this article, please visit http://dx.doi.org/ 10.1017/ice.2015.116
references 1. Osterman MJ, Martin JA. Trends in low-risk cesarean delivery in the United States, 1990–2013. National Vital Statistics Report Atlanta, GA: Centers for Disease Control and Prevention, National Center for Health Statistics, National Vital Statistics System 2014;63:1–16. 2. Brown HL. Informing the patient and the community about the implications of primary cesarean. Semin Perinatol 2012;36: 403–406.
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