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Epidemiology of nosocomial infections and mortality following congenital cardiac surgery in Cairo University, Egypt

El Tantawy, Amira Esmata; Seliem, Zeinab Salaha; Agha, Hala Monira; El-Kholy, Amany Alib; Abdelaziz, Doaa Mohameda

The Journal Of The Egyptian Public Health Association: August 2012 - Volume 87 - Issue 3 and 4 - p 79–84
doi: 10.1097/01.EPX.0000417997.16033.33
Original articles
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Background Nosocomial infections (NI) have been associated with significant morbidity and attributed mortality, as well as increased healthcare costs. Relatively few data on congenital cardiac surgical ICU NI have been reported from developing countries. Little is known about the epidemiology of NI following congenital cardiac surgery in Egypt. The aims of the present study were: (a) to estimate the incidence rate and types of NI among children admitted to Pediatric Surgical Cardiac ICU in Cairo University Children’s Hospital (Egypt) and (b) to estimate the mortality rate related to congenital cardiac surgery and identify its contributing risk factors.

Participants and methods A follow-up study in the period between 1 January 2009 and 1 January 2010 included all patients admitted to the Pediatric Surgical Cardiac ICU in Cairo University, Abo El Reesh Children’s Specialized Hospital (Egypt). Data were collected for each patient during the preoperative, intraoperative, and postoperative periods. Certain infection control procedures were carried out in certain months.

Results Of 175 patients, NI were identified in 119 (68%). Poor hand hygiene was associated with increased NI in certain months of the study duration. NI were significantly higher at a younger age [median 9 (5–30) months, P<0.03]. Mortality was found in 54 patients, that is, 31% of the study population. Mortality was significantly observed with younger age, higher complexity score for congenital cardiac lesions, prolonged cardiopulmonary bypass and ischemic times, NI, prolonged mechanical ventilation, prolonged central line insertion, and the use of total parenteral nutrition. Mortality among the NI patients was found in 44 of 119 (37%). On carrying out a multivariate analysis, Acute Physiology and Chronic Health Evaluation II score [P<0.001, odds ratio (OR) 1.13, 95% confidence interval (CI) 1–1.2], age (P<0.001, OR 0.3, 95% CI 0.2–0.4), and prolonged duration of mechanical ventilation (P<0.03, OR 2.8, 95% CI 1.1–7.2) were identified as risk factors of mortality.

Conclusion and recommendations NI rate and subsequent mortality were high among cases followed up during the period from 1 January 2009 to 1 January 2010 in the University Children’s Hospital (Cairo, Egypt). Early surgical interference, enforcement of proper infection control practices, especially hand hygiene, can reduce NI and trials for early extubation from mechanical ventilation might improve outcome following congenital cardiac surgery in pediatrics.

Departments of aPediatricc Cardiology

bMicrobiology and Infection Control, Faculty of Medicine, Cairo University, Cairo, Egypt

Correspondence to Amira Esmat El Tantawy MBBCH, MSC, PHD, Department of Pediatric Cardiology, Faculty of Medicine, Cairo University, 11995 Cairo, Egypt Tel: +20 168 202 723; fax: +20 237 600 992;e-mail: amiraesmat@yahoo.com

Received March 2, 2012

Accepted May 29, 2012

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Introduction

Nosocomial infections (NI) or hospital-acquired infections are infections that patients acquire during the course of receiving treatment for other conditions within a healthcare setting 1. NI may be caused by infections from endogenous or exogenous sources 2. Most published studies of ICU-acquired infections have been from hospitals in industrialized western countries, ranging from 3.7 to 11.6% 3–6. Studies carried out in healthcare settings in developing countries report hospital-wide NI rates outweighing those in developed countries, with prevalence rates varying from 13 to 33%, but most studies have reported values higher than 10% 7–9. NI had been associated with significant morbidity and attributed mortality, as well as markedly increased healthcare costs 10,11. There is a vast body of literature that shows that NI and device-associated infections (DAIs), particularly ventilator-associated pneumonia (VAP), catheter-associated laboratory-documented blood stream infection (CLABSI), and confirmed catheter-associated urinary tract infection (CAUTI), pose the greatest threat to hospital safety in the ICU 4–6,12.

NI lead to prolonged hospital stay, long-term disability, increased resistance of microorganisms to antimicrobials, huge additional financial burden for health systems, high costs for patients and their family, and unnecessary deaths 9. Studies carried out in US hospitals have shown that an integrated infection control (IC) program, including targeted outcome surveillance of DAIs, can reduce the incidence of NI by as much as 32% and lead to reduced healthcare costs 3.

The extent of this problem is completely evident in Egypt, which is a developing country. Congenital heart disease management in particular is a major challenge, with the burden of high costs and the need for special, skilled, and well-equipped cardiac centers. Abo El Reesh Children’s Hospital congenital cardiac surgery center is one of few centers that deals with complex congenital heart disease in Egypt. Improving the medical service in such a center would allow rapid turnover of beds at lower costs and cut the waiting list short. There has been no in-depth research on the epidemiology of NI following congenital cardiac surgery in Egypt. The aim of this work was to estimate the incidence rate of NI and to identify their types, to estimate the postoperative mortality rate related to congenital cardiac surgery, and to identify its determinants, to assess certain IC practice, namely, hand hygiene and IC measures for central venous catheter and urinary catheters at Pediatric Surgical Cardiac ICU (PSCICU) Cairo University.

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Participants and methods

The work was initiated as a follow-up study to estimate the incidence of NI and mortality rates in postcongenital cardiac surgery patients who were admitted in the postoperative PSCICU in Abo El Reesh Children’s Hospital Cairo University from 1 January 2009 to 1 January 2010. No patients were excluded from the study.

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Data collection methods

A data collection sheet was used to record the following data for each patient: (I) demographic data, which included: (a) sex. (b) Age: (two age groups: infants <1 year of age and children from 1 to 14 years of age). (II) Intraoperative data, which included: (a) categories of the complexity of surgical procedures (from 1 to 4). Surgical procedures were considered more complex if they were technically more difficult to perform or were usually performed on patients with complex disease representing the complexity of the surgery 13,14. (b) Determination of the type of operation, whether open cardiopulmonary bypass surgery or closed surgery, defining the bypass time and ischemic time for open surgeries. (III) Postoperative data, which included: (a) NI data: (i) diagnosis of NI and its types and DAIs according to the Centres for Disease Control and Prevention criteria 2. Infections were considered as nosocomial if they had developed within the ICU or within 48 h after discharge from the ICU. In addition, different DAIs were recorded: (a) VAP. (b) CLABSI. (c) CAUTI. (d) Surgical site infection 2 (ii) Observation of certain IC practices over 3 months’ duration: April, May, and June 2009; the full details of assessment of IC practices will be described later. (b) Other postoperative data included the Acute Physiology and Chronic Health Evaluation II (APACHE II) score of severity, which is a classification system for disease severity that uses a point score on the basis of the initial values of 12 routine physiologic measurements in addition to age, and previous health status to provide a general measure of the severity of disease, with an increasing score from 0 to 71 15, mechanical ventilation duration, central venous line duration, and the use of total parenteral nutrition (TPN). (c) Calculation of the duration of PSCICU stay for NI and mortality cases. (d) The final outcome is mortality before discharge. The total mortality rate and the mortality rate for NI-positive cases were calculated. The observational checklist for IC practices included the following: (a) observation of the frequency of hand washing between patients by the attending nurses, monitoring was carried out by IC personnel from the microbiology unit in addition to one physician assigned from the PSCICU team; each accounted for 3 days/week including observation during the morning, noon, and night shifts, selecting a random unplanned 1-h observation without previous notification, with a total number of at least 140 evaluations/week. The nurse-to-bed ratio in our unit was 1 : 3 to 1 : 4 during the study period 16. (b) Care practices for three selected points of the central venous line were registered at least 5 days/week: (i) Presence of sterile gauze, (ii) Registered date on administration sets, and (iii) check that the dressings are clean. These three points were selected as the starting points for our IC observation program of central lines care 17. (c) Urinary catheter care supervision module. This module included observation of all urinary catheters in the ICU in terms of the following: (i) Catheter position on the thigh without strangulation. (ii) The collecting urine bag not touching the floor 16.

Approval of the postgraduate ethical and scientific research committees of Faculty of Medicine at Cairo University was obtained before starting the work.

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Statistical analysis

All statistical calculations were carried out using the statistical package for the social science program (SPSS Inc., Chicago, Illinois, USA), version 16 for Microsoft Windows. Data were statistically described in terms of median (minimum and maximum). For categorical data, the χ2-test was carried out, whereas for numerical data, the Mann–Whitney U-test was used and the Kruskal–Wallis test was used for the comparison of the mean rank of three or more independent variables. P values less than 0.05 were considered statistically significant. Multivariate analysis using the odds ratio (OR) with a 95% confidence interval (CI) to identify the risk factors for NI and mortality was used.

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Results

During the follow-up period from 1 January 2009 to 1 January 2010, a total number of 175 patients were admitted to PSCICU. The study population included 88 males (50.3%) and 87 females (49.7%). The median age of the study population was 12 months (ranging from 6 to 36). The two age groups were distributed as follows: 113 infants (64%) and 62 children (36%). The incidence rate of NI was 68% (119/175). Figure 1 shows the monthly incidence rate of NI registered during the year of 2009. The median age of NI patients was 9 months (ranging from 5 to 30). The NI patients were considerably younger than patients without NI (P<0.029). Types of NI included the following: laboratory-confirmed blood stream infection in 48 patients (40%), VAP identified in 42 NI patients (35%), surgical site wound infection in 21 patients (17.5%), and CAUTI in nine patients (7.5%) Table 1 shows the different types of device-associated NI.

Figure 1

Figure 1

Table 1

Table 1

In terms of the IC practices, Fig. 2 shows the distribution of CLABSI over April, May, and June 2009. In terms of urinary catheter IC observation during the 3 months, no patients had CAUTI in June, with a statistical significant difference among the 3 months, with a P value less than 0.000. In terms of hand washing in between patients by the attending nurses, the total compliance throughout the study period (April, May, and June 2009) was calculated as a median of 47% (33–70%). Table 2 shows the 3 months of IC observation.

Figure 2

Figure 2

Table 2

Table 2

The median duration of PSCICU of the NI patients was 10 days (7–13) vs. 5 days (4–7) (P<0.000) among non-NI patients. The mortality rate that was observed during the study period was 30.8% (54 patients) of the study population. NI patients had significant mortality (44/175) (25%, P<0.01). No statistically significant difference was observed in terms of sex and mortality (29 males vs. 25 females, P=0.5) and no statistically significant difference was observed in terms of mortality among the 3 months of IC observations (P=0.4). Patients who died were significantly younger (P<0.003), had a higher APACHI II score, with a median of 13 (3–20) (P<0.007), a higher complexity score for congenital cardiac lesions (P<0.002), longer cardiopulmonary bypass time and ischemic time (P<0.006 and P<0.002, respectively), longer duration of mechanical ventilation (P<0.000), longer duration of central venous line (P<0.000), use of TPN, and longer duration of PSCICU (P<0.02), Table 3 shows significant mortality patients data.

Table 3

Table 3

On carrying out multivariate analysis, age (OR 0.3, 95% CI 0.2–0.4), APACHE II score (OR 1.13, 95% CI 1–1.2), and prolonged mechanical ventilation (OR 2.8, 95% CI 1.1–7.2) were identified as the risk factors of mortality following congenital cardiac surgery Table 4 shows the OR for multivariate analysis of different risk factors for mortality.

Table 4

Table 4

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Discussion

In recent years, the attitude toward quality of healthcare and the cost of congenital heart surgery has received considerable attention from the public and has been the subject of government coverage scrutiny 18. In this study, of the 175 patients enrolled, 119 (68%) patients were found to have NI, which is a high rate when compared with other published data from both developed and developing countries (11–52%) 19–22. Many contributing factors may be responsible for this high figure: first, the delay in the application of strict IC practices and policies in our center as we started to consider IC policies by the beginning of 2009, when we joined the International Nosocomial Infection Control Consortium project, which is a prospective multicenter surveillance study for NI and DAI for developing countries worldwide. The second factor is that during the year 2009, we had a nurse-to-bed ratio of 1 : 3–1 : 4, whereas it was 1 : 2– 1 : 3 in other publications with relatively similar settings 20. Some studies have shown that overcrowding, understaffing, and imbalance between workload and resources are important determinants of NI 23. However, improvement of the NI rate is not impossible as with the 3-month observation for the IC practices, there was an improvement in the laboratory-confirmed blood stream infection rates from 37 to 12% with strict IC. In the study carried out by Costello et al. (2008), compliance with the use of the central venous line maintenance bundle in the ICU improved from 8% (n=323 observations) during the partial intervention period to 99% (n=60 observations) during the full intervention period (P=0.004) 17. Many authors have reported on the improved surveillance process outcome for the central venous lines bundle of care policy adopted by each PSCICU separately 10,12,17. In terms of the observation of IC practices, the overall rate of hand washing in between patients by practicing nurses was 47.1% (33–70%), which was comparable with other publications, ranging from 20 to 70% 16,17,24. In our study, young infants were more prone to NI, a finding that is similar to many other publications 15,22,25,26.

In our study, the mortality rate was about 31%, which is considered high when compared with the other rates reported by many authors (3–23%) 12,20,21. Our explanation for this high mortality rate is that most of the patients had delayed presentation for diagnosis with relatively high complexity score and subsequent serious complication occurred as pulmonary hypertension following large ventricular septal defects. Long waiting list adds to failure to thrive in most of the patients being prone to more NI, factors that are mentioned as contributing to mortality in publications before 18–28. Although in our series no significant difference in mortality was observed between males and females (P=0.9), other publications have reported unexplained female sex as a risk factor for mortality after congenital cardiac surgery 29,30. In our series, significant mortality was observed with younger age and prolonged duration of the use of invasive devices such as mechanical ventilators and central venous lines. Many series have studied the risk factors and associations with mortality in relation to congenital heart surgery, reporting the same factors as ours, especially the prolonged use of invasive devices 18,31–34. In our series, the use of TPN showed a statistically significant association with mortality (P<0.000), probably linked to complicated cases and prolonged use of the central line. Thomson et al. 35 have reported a role for TPN as a risk factor of mortality following congenital cardiac surgery. In this study, younger age, high APACHE II scores, and prolonged mechanical ventilation were found to be risk factors for mortality. A higher APACHI II score determined on the first postoperative day was found to be associated with increased mortality, especially if the score exceeded 28 36.

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Conclusion and recommendations

NI and mortality rates after congenital cardiac surgery were high in the children’s hospital in Egypt that was studied here. Several factors may have contributed to the high mortality rate such as age, hospital-acquired infection, bypass time, ischemic time, total ICU duration, central line duration, and APACHE II score. Implementation of policies that allow early screening and diagnosis of congenital heart disease, followed by the proper selection of patients before congenital heart surgery, together with the strict application of IC policies in pediatric postoperative intensive care units, are the key for solving this problem.

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Acknowledgements

Conflicts of interest

There are no conflicts of interest.

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Keywords:

infection control application; mortality risk factors; nosocomial infections; pediatrics; postcongenital cardiac surgery

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