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Indian Journal of Community Medicine

Nosocomial Infections and Hospital Procedures

Author(s): P.S. Ganguly, Md. Yunus Khan, Abida Malik*

Vol. 25, No. 1 (2000-01 - 2000-03)

Departments of Community Medicine and Microbiology J.N. Medical College, A.M.U., Aligarh, U.P.

Abstract:

Research question: Is there any association between operative and post-operative hospital procedures and infection rates?

Objective: To determine the rate of nosocomial infection in post-operative patients and its association with different policies/procedures followed in the hospital.

Study design: Hospital based study with follow-up till the discharge from hospital.

Setting: Surgical wards of J.N. Medical College Hospital, Aligarh.

Participants: A sample of 422 patients selected from the patients admitted to the surgical wards during one calender year.

Study variables: Duration of operation, order of operation, application of rubber drain at incision site, pre-operative hospital stay, pre-operative antibiotic prophylaxis.

Outcome variable: Development of nosocomial infection during the post-operative hospital stay.

Statistical analysis: Chi-square test.

Results: Overall incidence of nosocomial infection was 38.8%. All the study variables were significantly associated with the development of nosocomial infection during post-operative period.

Conclusion: Certain hospital procedures are significantly associated with post-operative nosocomial infection rate and they can be easily modified to bring down the nosocomial infection rate.

Keywords: Hospital procedures, Nosocomial infection rate, Duration of operation, Order of operation, Pre-operative hospital stay, Pre-operative antibiotic prophylaxis.

Introduction:

Nosocomial infection is a major public health problem throughout the world. WHO1 has described it one of the major infectious diseases having huge economic impact. It is estimated that at any point of time more than 1.4 million people are suffering from nosocomial infections in the world. There is no doubt that this figure is only the tip of the iceberg as the record keeping system in most of the developing/underdeveloped nations are quite poorly evolved and managed. More than 50% of these infections can be prevented if sufficient data about their risk factors are available and relevant preventive measures are adopted. In recent days, as more and more invasive diagnostic and therapeutic procedures as well as indiscriminate use of antibiotics are being practised, the problem of nosocomial infection is posing more complex challenges2-8

Direct association of nosocomial infection with factors like pre-operative hospital stay and duration of operation has also been described2,5,9.. In the present study, an effort has been made to find out how significantly some of these factors are associated with nosocomial infections in a typical public sector tertiary care hospital in India.

Material and Methods:

The present study was conducted on 422 patients selected by systematic sampling from the patients admitted to the surgical wards of J.N. Medical College Hospital, Aligarh during the period of one year. Patients were observed and investigated from the pre-operative period through the post-operative period till discharge from the hospital, for the development of any of the following nosocomial infections - wound infection, urinary tract infection and lower respiratory tract infection. Diagnoses were confirmed by clinical and bacteriological examinations as recommended by WHO, 19811.

Results :

Table I: Nosocomial infections in relation to duration of operation.

Duration of operation (hrs) Total number of patients Number of patients who developed infection Percentage
<1 172 53 30.8
1-2 219 92 42.0
>2 31 19 61.2
Total 422 164 38.8

X2=12.36, p<0.01

Infection rate was minimum (30.8%) when the (61.2%) when the duration was beyond two hours duration of operation was less than one hours and maximum

Table II: Distribution of nosocomial infections according to order of operation.

Order of
operation
Total number
of
patients
Number of
patients who
developed
infection
Percentage
Ist 159 42 26.4
2nd 103 43 41.7
3rd 59 30 50.8
4th & above 12 7 58.3
Total 333* 122 36.6

*Emergency operations excluded, X2=15.30, p<0.005

On a single day several patients are operated in an operation theatre (O.T.). It was observed that infection rate was minimum (26.4%) in the first operation of the day. Subsequent operations performed later in the day, showed an increasing rate of infection and the difference was statistically significant.

Table III: Nosocomial infections in relation to application of drain at incision site

Application
of drain
Total number
of patients
Number of
patients who
developed
infection
Percentage
Yes 215 78 36.2
No 207 48 23.1
Total 422 126 29.8

X2=8,62, p<0.01

Nosocomial infection rate among patients in whom rubber drain was applied at incision site was significantly higher (p<0.01) than the patients in whom drain was not applied

Table IV : Nosocomial infections in relation to duration of pre-operative hospital stay.

Pre-op. hosp.
stay (days)
Total number
of patients
Number of
patients who
developed
nosocomial
infection
Percentage
<7 318 98 30.8
7-14 76 42 55.2
15-21 25 22 88.0
>21 3 2 66.6
Total 422 164 38.8

X2=42.16, p<0.001

Infection rate was minimum (30.8%) when preoperative hospital stay was less than 7 days and it was maximum (88.0%) when pre-=operative stay was prolonged beyond two weeks. The difference was found to be significant (p<0.001).

Table V: Relationship between pre-operative antibiotic prophylaxis and nosocomial infections.

Pre-op. antibiotic
prophylaxis
Total number
of patients
Number of
patients
who developed
nosocomial
infection
Percentage
Received 135 84 62.2
Not received 287 80 27.8
Total 422 264 38.8

X2=45.58, p<0.001

Post operative infection rate was significantly (p<0.001) higher (62.2%) in patients receiving preoperative systemic antibiotic prophylaxis than those who did not receive it (27.8%).

Discussion:

The association between duration of operation and post-operative infection rate suggests that longer duration of exposure of wound during operation makes the wound more vulnerable to contamination by microorganisms either from air or dust particles of the OT or from surgical instruments and members of the surgical team. The same view was expressed by Brachman9.

Significant relationship between order of operation and post-operative infection rate was observed in this study. It seems when the first operation of the day was performed the OT was freshly prepared and so less amount of contaminants were present in the vicinity. The surgical team was also quite fresh at the begining of the day. As the day progressed, the amount of microbial contaminants in OT atmosphere increased with increased movement and activities of the staff. Hence a higher infection rate was observed in operations performed later in the day i.e; lower order in the operation list.

Simchen et al6 and Subramanian et al7 have described that the risk of post-operative nosocomial infection increases when an open drain in put in incision site. They opined that the drain itself acted as a portal of entry for pathogenic organisms. In the present study too, we observed significantly higher infection rate in patients with open drain at incision site, compared to other patients.

A direct relationship between pre-operative hospital stay and post-operative nosocomial infection rate has been reported by authors like Bucknall2, Mertens5 and Brachman9. Longer pre-operative stay increases colonization in patients with nosocomial strains of bacteria which are more resistant to antiboitics. Cruse10reported that longer stay in hospital also indirectly increases infection rate by lowering patients' resistance. The findings of the present study is in conformity with that of the other authors. Contrary of common belief, we have observed that routine administration of antibiotics of pre-operative periodserved that routine administration of antibiotics of pre-operative period increased the risk of post-operative infection. Bucknall 2 commented that except for some operations like large bowel surgery, urinary tract surgery, biliary tract surgery etc; where pre-operative antibiotics has a definite role, routine pre-operative antibiotic prophylaxis in all operations should be discouraged. Gedebou et al4 and Delgado-Rodriguez et al11 have also described that post -operative infection rate in patients given pre-operative antibiotic prophylaxis was higher than patients not receiving such prophylaxis. Increased use of antibiotics without definite indications may have an adverse impact on the hospital flora and consequently infections with more resistant bacteria may become commoner. It can be rightly said that risk of toxicity and resistance is too high a price to pay for a little and doubtful advantage.

Conclusion:

The problem of nosocomial infection is a multifaceted one and the role of certain hospital procedures in its etiology cannot be ruled out. In the present study, a number of hospital procedures were found to be associated significantly with higher rates of nosocomial infection. In depth analysis of these variables (hospital procedures) may lead us towards primary prevention of a large problem. Every year a huge amount of health resources are wasted in the hospitals in the form of low bed turn-over (longer hospital stay), high expenditure on costly antibiotics etc. due to post-operative nosocomial infections. A little modification in these hospital procedures can curb down the nosocomial infection rate in a hospital in a cost-effective way.

References:

  1. WHO. Surveillance, control and prevention of hospital acquired (nosocomial) infections. Report of an advisory group 1981; BAC/NIC/81.6.
  2. Bucknall TE. Factors affecting the development of surgical wound infection - a surgeon's view. J Hosp Infect 1985; 6: 1-8.
  3. Davis M et al. The DANOP-DATA system - a low cost personal computer based programme for monitoring of wound infections in surgical wards. J Hosp Infect 1989; 13: 273-279.
  4. Gedebou M, Habete-Gabr E, Kronvall G et al. Hospital acquired infections among obstetric and gynaecological patients at Tikur Anbessa Hospital, Addis Ababa. J Hosp Infect 1988; 11: 50-59.
  5. Mertens R, Kegels G, Stroobant A et al. The national prevalence survey of nosocomial infections in Belgium. J Hosp Infec 1987; 9: 219-229.
  6. Simchen E, Shapiro M, Michel J. Multivariate analysis of determinants of post-operative wound infections in orthopaedic patients. J Hosp Infect 1984; 5: 137-146.
  7. Subramanian KA, Prakash A, Shriniwas G et al. Post-operative wound infection. Ind J Surg 1973; 35(2): 57-59.
  8. Wasek A, Basu AK. Chatterji BD. Studeis on hospital infection. J Ind Med Asscn 1965; 44: 457.
  9. Brachman PS. Nosocomial infection control - an overview. Rev Infect Dis 1981; 3: 640-648.
  10. Cruse PJE. Surgical wound sepsis. Can Med Asscn J 1970; 102: 251-258.
  11. Delgado-Rodriguez M, Cueto-Espinar A. Qualification of risk factors in hospital infection at a surgical service. Eur J Epidemiol 1988; 4(2): 235-241.
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