A prospective study on laparotomy wound infection

CERTIFICATE

This is to certify that dissertation entitled ‘A PROSPECTIVE STUDY ON

LAPAROTOMY WOUND INFECTION’ is a bonafide record of work done by

Dr. JAMSHEER V. T in the Department Of General Surgery , THANJAVUR

MEDICAL COLLEGE, THANJAVUR , during his post graduate course from

2015-2018 under guidance and supervision of Prof. DR. V.KOPPERUNDEVI MS ,

DGO & PROF. DR.M. ELANGOVAN, MS ., FICS ,this is submitted in partial

fulfilment for the award of M.S. DEGREE EXAMINATION- BRANCH I

(GENERAL SURGERY) to be held in MAY 2018 under the TAMILNADU

DR. M.G.R. MEDICAL UNIVERSITY, CHENNAI.

DR.V.KOPPERUNDEVI, MS.,DGO PROF.DR. M.ELANGOVAN M.S., F.I.C.S Associate Professor & Chief, Professor and Head of Department,

Department of General Surgery, Department of General Surgery, Thanjavur Medical College, Thanjavur Medical College, Thanjavur Thanjavur

The Dean,

DECLARATION

I declare that this dissertation entitled ‘A PROSPECTIVE STUDY ON

LAPAROTOMY WOUND INFECTION’ is a record of work done by me in

Department of General Surgery , Thanjavur Medical College , Thanjavur ,

during my post graduate course from 2015-2018 under the guidance and

supervision of my unit chief DR.V. KOPPERUNDEVI, MS, DGO and

PROF AND HEAD OF DEPARTMENT, PROF .DR M. ELANGOVAN, MS.,

FICS .It is submitted in partial fulfilment for the award of MS DEGREE

EXAMINATION-BRANCH 1 (GENERAL SURGERY) to be held in may

2018 under the TAMIL NADU DR.MGR MEDICAL UNIVERSITY

,CHENNAI. This record of work has not been submitted previously by me for the

award of any degree or diploma from any other university

THANJAVUR DR.JAMSHEER V.T

ACKNOWLEDGEMENT

I express my extreme gratitude to Prof. Dr. M.ELANGOVAN M.S., F.I.C.S.,

Professor and the Head of the Department of Surgery, for his constant guidance

and suggestions throughout my study period.

I express my extreme gratitude to Dr. V. KOPPERUNDEVI, M.S.,DGO

Associate Professor and my Unit Chief, for her valuable guidance and

encouragement during my study period.

I express my profound gratitude to Asst Prof., Dr.V.PANDIYAN MS.,

Dr. THIVAGAR MS, Dr.SARAVANAN M.S for their valuable guidance and

encouragement.

I owe thanks to all ASST.PROFFESSORS OF DEPARTMENT OF

SURGERY for their valuable guidance

I thank DEAN, THANJAVUR MEDICAL COLLEGE for permitting me to

use the hospital facilities for my study .

I express my sincere thanks to all patients, who in spite of their physical and

mental sufferings have co-operated and obliged to my request for regular follow

CONTENTS

1. INTRODUCTION 1

2. AIMS AND OBJECTIVE OF STUDY 3

3. REVIEW OF LITERATURE 4

4. MATERIALS AND METHODS 28

5. OBSERVATION AND RESULTS 33

6. DISCUSSION AND CONCLUSION 55

7. BIBLIOGRAPHY

8. PROFORMA

INTRODUCTION

Laparotomy or celiotomy is a surgical procedure in which incision is put on abdominal

wall in order to approach intra-abdominal or abdominal wall pathologies. Laparotomy

etymologically originated from the Greek word LAPAROS , which means soft or

loose. Pioneer in laparotomy was Ephraim in 1809. He performed surgery without any

anaesthesia. Christian Albert Theodor Billroth(1) is known as the father of abdominal

surgery. He had done the first successful gastrectomy for pyloric cancer.

Even though laparotomy is a very common surgical procedure, we may have to

encounter many difficulties in both intraoperative and post- operative period. Surgical

site infection is one of the most common post-operative complication in laparotomy

patients. The end result of laparotomy not only depend upon the severity of underlying

illness but also depends upon abdominal incisional wound healing. Delay in wound

healing leads to increased duration of hospital stay and also the hospital expenses.

According to one study, there is an average increase of 7.3 days of hospitalisation which

is caused by surgical site infection.(2)

From patient perspective, surgical site infection cause both prolongation of ill health

and increase the mental agony about his disease. From surgeon’s perspective, even

though surgical site infection are inevitable it can be minimised to a very good extend if

SSI not only increase length of hospital stay but also contribute to morbidity and

mortality . It also causes physical and psychological trauma to the patient ; ultimately

OBJECTIVES

• To analyse incidence of wound infections

• To identify most common organisms

• To determine the relationship of post-operative wound infection with certain

predisposing factors

LITERATURE REVIEW

BASIC ANATOMY OF ANTERIAL ABDOMINAL WALL

It is bounded by superior process and costal margin posteriorly by vertebral

column and inferiorly by upper part of pelvic bone. Its layers consists of skin, superficial

fascia, muscle and their deep fascia, extra peritoneal fascia and parietal peritoniam.

SUPERFICIAL FASCIA

Consist of,

• Superficial fatty layer of camper

• Deep membraneous layer of scarpa

MUSCLES OF ANTERIOLATERAL ABDOMINAL WALL

There are 5 muscles in anteriolateral group of abdominal wall. 3 flat muscles,

which includes external oblique, internal oblique and transversus abdominis. 2 vertcal

muscles near midline which are enclosed within tendinous sheat followed aponeurosis of

TECHNICAL CONSIDERATION REGARDING ABDOMINAL INCISION

VERTICAL INCISIONS

MIDLINE INCISION

It gives rapid access to and, adequate exposure of almost every region of

abdominal cavity and retroperitoneum. It is typically associated with little blood loss and

does not require transection of muscle fibre or nerves. Upper midline incision provides

adequate exposure to oesophageal hiatus, abdominal easophagus, vagus nerves, stomach,

duodenum, gall bladder, pancreas and spleen. Lower midline incision provides exposure

PARAMEDIAL INCISION

Paramedical incision are vertical incisions placed either to the right or left of the

midline on abdominal wall. During creation of paramedical incision of lower abdominal

wall, the inferior epigastric vessels may be encounters and must be ligated prior to

C

SSI (SURGICAL SITE INFECTIONS)

Surgical site infections are infections arising at the site of previous surgical procedure,

which detected before 30 days. Depending upon the depth of infection it is divided into 3

categories. Superficial incisional SSI (above facial layer) ,deep incisional SSI and organ

space infection. Deep incisional SSI and organ space infections are together called

complex surgical site infections .Stich abscess is not included under SSI. Even though

some sort of erythema is expected at the surgical site , peri-incisional pain and

tenderness, expansion of erythema, purulent discharge from surgical site should raise the

suspicion about development of surgical site infections and should be properly intervened

and treated. Most common nosocomial infection in surgical patients is SSI and each SSI

CLASSIFICATION OF WOUNDS

Depending on extend of Wound contamination, National Research Council put forward a

wound classification scheme in 1964, which includes 4 classes of wounds

CLEAN:

Uninfected surgical wound in which no inflammation is encountered,

clean wounds are closed primarily

Examples:-

• exploratory laparotomy

• non-penetrating blunt trauma

• neck surgery

• thyroidectomy

CLEAN CONTAMINATED:

Procedures involving GI or respiratory tract with no significant contamination.

Examples:-

• small bowel resection

• whipple procedure

• routine appendectomy

• cholecystectomy

CONTAMINATED:

Examples:-

• appendectomy for inflamed appendicitis

• bile spillage during cholecystectomy

• diverticulitis.

DIRTY OR INFECTED:

Acute bacterial inflammation found, pus encountered, devitalised tissue encountered.

Example:-

• incision and drainage of abscess

• peritonitis

• bowel perforation.

Wound classification has an important role in predicting risk of post op SSI. But some

studies indicates this classification alone is inaccurate.

There many better scoring system to calculate risk of SSI, commonly used are SENIC

(STUDY OF EFFICACY OF NOSOCOMIAL INFECTION CONTROL) & NNIS

(NATIONAL NOSOCOMIAL INFECTION SURVEILLANCE) Risk index

4 features are used in SENIC scoring

1. surgery more than 2 hours

2. 2 abdominal surgery

3. 3 wound class 3 /4

SENIC SCORE AND RISK OF SSI

• 0…..1%

• 1…….3-6%

• 2……9&

• 3…….17%

• 4…….27%

NNIS uses 3 instead of 4 variables which includes(3)

• ASA more than 2.

• Prolonged duration of surgery

• Wound class III/IV

SOUTHAMPTON WOUND GRADING SYSTEM FOR WOUND HEALING

0) Normal healing

1) Normal healing with mild arythema

a) Some bruising

b) Considerable bruising

c) Mild arythema

2) Erythema with other signs of inflammation

a) At one point

b) Around sutures

d. Around wound

3) Clear or hemoserous discharge

a) At one point

b) Along wound

4) Pus

a) At one point

b) Along wound

5) Deep or severe wound infection with or without wound infection, heamatoma

The ASSEPSIS wound score additional treatment

Crieteria points

Additional treatment 0

Antibiotics for wound infection 10

Drainage of pus under Anastasia 5

Debridement of wound under general Anastasia 10

Serous discharge daily 0-5

Erythema daily 0-5

Purulent exudate daily 0-10

Separation of deep tissue daily 0-10

Isolation of bacteria from wound 10

Stay as inpatient prolonged more than 2 weeks 5

ANTIBIOTICS PROPHYLAXIS

Recommended antibiotics prophylaxis (university of CINCINNATY hospital) for

colorectal surgery is cefazoline plus metronidazole and hepatobiliary surgery are

piperaziline. For maintaining adequate plasma concentration of drug we may have to

repeat the dosage especially in long duration surgical procedures

Antibiotics should be administered 30-60 min before planned incision.

Antibiotic prophylaxis is recommended in patients with class 2,3,4& in class 1 with other

RISK FACTORS FOR DEVELOPMENT OF SSI

1. PATIENTS FACTORS

• Ascites (abdominal surgery

• Corticosteroid therapy(controversial)

• Obesity

• Diabetes

• Extremes of ages

• Hypocholesterolemia

• Hypoxia

• Postoperative anaemia

• Remote infection

• Under nutrition

2. ENVIRONMENTAL FACTORS

• Inadequate sterilisation

• Inadequate ventilation

• Inadequate skin antisepsis

3. TREATMENT FACTORS

• Drains

• Emergency procedure

• Hypothermia

• Oxygenation

• Prolonged operative time

• Prolonged preoperative hospitalisation

AGE

Old age patients are more prone for delayed wound healing which is due to reduced

re-epithelisation of skin, they may be having multiple comorbidities which may affect

collagen replacement after abdominal surgery.(5)

DIABETES

Diabetes associated with small vessel disease, neuropathy, altered glycaemic control(6)

all of which are predisposed to alteration in normal wound healing pathway. Common

problems seen in diabetes are increased risk of infection, delayed epithelialisation,

alteration in collagen synthesis and granulation tissue formation. In diabetes, matrix

metalloprotien function are also altered which are integral component of wound healing

IMMUNODEFICIENCY

Immunocompromised state ( old age , malnourishment, cancer, HIV) can also result in

poor wound healing.

OBESITY

Even though extensive studies carried out over this factor it has only a weak

LENGTH OF PRE-OPERATIVE HOSPITALIZATION

When the duration of preoperative hospitalisation period increases risk of SSI also

increases .It is thought to be via bacterial colonization especially with resistant organism

there evidence from 5 & 10 year studies by Cruse and Foord and the study by Mead et al

support this, but both of these studies didn’t consider comorbidities , skin flora and

organisms identified from culture. So the association between length of pre-operative

hospitalization & SSI is less significant

PRE-OPERATIVE SKIN PREPARATION

In 1971 Serropian and Reynolds studied surgical site infections in various types of skin

preparation ; which showed of 5.6% after razor shaving and 0.6% after depilator use and

0.6% after no hair removal (7) Alexander et al investigated on 1013 patients ; done an

RCT ; observations revealed that morning clipping showed lowest incidence (3.2%) and

others were significantly high (8). Mechanism of surgical site infections is because skin

aberration that may get infected by proliferative microorganisms. In contrary to our

common belief some studies even tell no need for skin preparation. If skin preparation is

indicated skin clipping is ideal

PROLONGED OPERATIVE TIME

Duration of surgery is also an independent factor which determines surgical site

infections. ( 9) especially if duration more than 2-3 hours

PERI-OPERATIVE FACTORS

Normothermia and absence of hypothermia increase tissue perfusion and helps in

TREATMENT FACTORS

Treatment with drugs such as steroids, NSAID, anti-cancer / antimitotic drugs, radiation

(RT) can also affect wound healing adversely. Ill effect of steroid on wounds planned for

secondary and tertiary wounds can be reduced by topical application of vitamin A.

antimitotic drugs and radiation therapy impedes cell cycle in rapidly dividing cells.

Moreover malignancy may also present with malnourishment or cancer cachexia.

Administration enteral nutritional support improves healing in malignancy

REMOTE SITE INFECTION

In 1976, study conducted by Edward (by including 1865 patients) shown a

epidemiological correlation between remote site infection and SSI. Especially in case of

UTI. But it is not recommended that the treatment of above conditions are mandatory

prior to surgery (10).

MALNOURISHMENT

In 1995 Rhodes and Alexander studied about correlation between malnourishment and

wound healing especially emphasising on hypo proteinemia, by taking serum protein less

than 6.3 as the cut off. Ehrenkrenz could not establish similar outcome as Rhode’s study,

they used patients with albumin values upto 2.8 mgs/dl, 2.8-3.4 mg/dl and more than 3.4

mg/dl.

MALIGNANCY

The presence of Malignancy and associated immunity reduction also considered to

be a risk factor for surgical site infection. Studies, however shows variable reports

444 Gastric surgery did not find any independent association between malignancy and

wound infection (11) where as Claesson and Holmlund observed a rate of 17% versus

4.5% of SSI in malignant & non malignant cases respectively.(12)

DETERMINANTS OF WOUND INFECTION

Two important predictors of SSI are:

• bacterial Contamination.

• Host resistance

A formula derived by Culberson and Altemier to predict SSI is,

This formula explains the positive correlation between risk of SSI with bacterial load and

its virulence

Dose of Bacterial Contamination x Virulence

Risk of surgical wound infection = ______________________________

Host resistance

EXOGENOUS FACTORS

Surgeons Hands

There are various types of antiseptics used for scrubbing most commonly used are

Povidone – Iodine and Chlorohexidine which are effective against both gram +ve and

gram –ve organizisms. The variation comes in the length of the scrub which might vary

GLOVE PUNCTURE

Among studies regarding glove puncture the important 2 studies are conducted by

Cruse and Foord, Whyte Et Al, both of these studies shows there is no increase of SSI

showing glove puncture and it is thought to be due to preoperative scrubbing. So glove

puncture is not considered to be a serious factor in development of SSI.

EMERGENCY PROCEDURES

An important study conducted by Garibaldy et al compared the incidence of SSI

between emergency vs elective procedures. Wound infections shows an odds ratio of 7.6(

CI 95% 3.2-18.2) for emergency vs elective surgeries. After multivariate analysis of this,

it was found to be insignificant.(14). So, Emergency operations by themselves are not

considered to be a predisposing factor to development of SSI.

PROCEDURE DURATION

As the duration of surgery increases the chance for SSI is also high. Especially if the

procedure duration is more than 2-3 hrs. there are many studies regarding this topic.

Examples, Cruse and Foord, Garibaldy and et al, Haley et al, Culver et al. among this

Haley et al studied more than 55000 and found that duration of surgery more than 2 hrs is

the 2nd greatest risk factor for development of SSI. In our study we grouped surgical

OPERATING SURGEON

In any institution surgery is commonly done by different category of doctors

ranging from intern or trainee surgeon to consultant surgeon or chief surgeon. Most of

studies shows that it is not an easy task to compare SSI rate among various group of

surgeons due to multifactorial reasons. One of the possible way to tackle these is studying

surgeon’s specific infection rate. Even though assessment is difficult, operating surgeon

WOUND CATEGORY

WOUND CATEGORY

In 1964 National Research Council proposed a wound classification system in

which all the wounds are classified from grade 1-4 depending upon the wound

contamination. For comparison purpose in our study we combined grade 3 and grade 4

together.

Table 4(A) Table on wound infection rates among various studies.

Institution Year(s)

Sample

size Class infection rate % of

(No, of patients) I (%) II III Overall Incidence Foot Hills

Hospital, Canada 1967-77 62939 1.5 7,7 15.2/40 4.7

MPLS VALC 1977-86 40915 1.4 2.8 8.4 2.5

SENIC 1975-76 59352 2.9 3.9 8.5/12.6 4.1

NAS-NRC 1964 15613 5.1 10.8 16.2/29 7.5

Category I : Clean

Category II : Clean – Contaminated

Category III : Contaminated and Dirty

Wound contamination is the single most predictor of development of SSI. So the

classification proposed by National Research Council is a very reliable tool for prediction

SURGICAL DRAPES

Drapes are used for isolating operating area from other body part. Commonly used

surgical drapes are cotton drapes, pre-fabricated drapes and plastic drapes. The issue we

encounter with cotton drapes are bacteria can pass from unsterile area to sterile area once

the drape is wet. While using adhesive plastic drapes there is increased chance of

infection due to proliferation of bacteria by sweating beneath plastic drapes( 17).

OTHER FACTORS AFFECTING THE INCIDENCE OF WOUND INFECTIONS

Some other factors to be considered for [proper wound healing and prevention of

SSI are, achieving complete haemostasis, adequate blood supply to the wound, dead

space obliteration, tensionless suturing.

POST OP SURVIELLANCE

Wound infection, review is incomplete without proper surveillance. Proper

surveillance has shown to be an important factor reducing SSI in many studies. So many

surgical societies and disease control centers set recommendations to reduse SSI to the

MATERIALS AND METHODS

SETTING

This prospective study was conducted at TMCH ( Thanjavur Medical Collage and

Hospital ,Thanjavur) during the period of september 2016-september 2017.

SAMPLE POPULATION

Those patients underwent major laparotomy during above mentioned period are included

in this study, patients undergoing appendectomy, laparoscopic surgery, those who are not

willing for participating in study and those patients who are morbidly ill are excluded

from the study.

DATA RECORDING

Data recording done using proforma, a sample of which is enclosed in appendix I,

collection of date was done by M. S PG of department of surgery.

CLASSIFICATION OF CASES

Patients were grouped into 3 categories as mentioned earlier. Clean, contaminated and

PROCEDURE DONE

Laparotomy was done for various abdominal pathologies. They are categorized as

follows.

Intestinal obstruction

Hollow viscous perforation

Uppere GI surgeries )such as gastrectomy TV GJ cholecystemy)

Colorectal surgeries ( such as LAR/APR…)

Gynaecological pathology

Other procedure such as iliostomy reversal.

NATURE OF PROCEDURE

Depend on nature of procedure they are categorized into emergency or elective

procedure.

RISK FACTOR CATEGORIZATION

Depending upon the nature of risk factor, categorized into general or local risk factors.

General factors includes, presence of anemia, diabetis, TB and malignancy. Local risk

factors includes URI, LRI and UTI.

PER OPERATIVE FACTORS

DURATION OF SUREGERY

Time taken from induction of Anastasia to skin closure is considered here. We have

categorized into 3 groups. Less than 1 hr, 1 -2 hr, more than 2 hr.

PERFORMING SURGEON

In order to assess the role of performing surgeon in the incidence of SSI, we have

categorized performing surgeons into 3 groups. Chief or assistant professor or post

graduate.

ANTIBIOTICS

The role of antibiotic study in 2 different timings pre- and per operative. Pre operative

antibiotic usage could have been deliberate as in contaminate, pre- contaminate case and

incidental if patients had been known antibiotics for some other reasons such as

respiratory tract infections or UTI. Per operative antibiotics is given in patients as part of

prophylactic hygiene or if there is any gross unexpected contamination or in situations

where undue prolongation of surgery has occurred

IDENTIFICATION OF SSI (in the post operative period)

based on both clinical and microbiological findings SSI was diagnosed

CLINICAL CRITERIA

Clinical features used are progressive redness, swelling, tenderness, with or without

constitutional symptoms. Fever with more than 100 degree Fahrenheit was taken as

MICROBIOLOGICAL ANALYSIS

Serous or serosanguinous discharge were sent for microscopy, culture and sensitivity at

the time of detection. If any organism grove in the sample they were classified in infected

group. Even in the absence of other clinical signs. In the absence of above set criteria the

case were taken as not infected. If both clinical and positive culture was present then also

it was taken as infected.

ANALYSIS IN INFECTED CASES

Among infected cases day of detection, method of detection and organism grown and

outcome were studied.

DAY OF DETECTION

The day in which above said clinical characteristics present or the sample sent from a

suspected discharge which subsequently found to be positive was taken as day of

detection. If both clinical and microbiological criteria are met then whichever is earlier is

taken as day of detection

METHOD OF DETECTION

ORGANISMS GROWN

There are 6 categories in this variable.

1) No growth

2) Staphylococcus and streptococcus species

3) Klebsiella and E-coli

4) Pseudomonas

5) Citrobacter

6) Others

OUTCOME

Depend upon whether the case is resolved or not.

RESOLVED: symptoms and signs subsided following either drainage of abscess or by

proper administration of antibiotics. This group also includes infected wounds healed,

even following secondary suturing.

NOT RESOLVED: this group comprises patient went for septicaemia, fistula formation,

wound dehiscence or cutaneous gangrene.

STATISTICAL ANALYSIS

In our study we used excel software and epi info statistical package (version 6.04 ,

WHO and CDC) this factors for development of SSI were identified using Univariate

analysis. Hypothesis was tested using Chi square and Fischer’s test. Statistical

RESULTS

TABLE 6(A)

INCIDENCE OF SSI

TABLE 6(A). DISTRIBUTION OF WOUND INFECTION (n = 323)

Wound Frequency Percentage

Not Infected 286 88.6

Infected 37 11.4

Total 323 100

Total no. of patients included in the study was 323.

TABLE 6(B )

DISTRIBUTION OF AGE OF PATIENTS

Our sample had a cut off of minimum age of 16 and maximum age of 75 with a median

age of 35.

Minimum Age

Maximum Age

Median

:

:

:

16 years

75 years

35 years

Group 1 : up to 20 years

Group 2 : 21 – 40 years

Group 3 : 41 – 60 years

Group 4 : 61 and above years

For analysing patients with different age groups patients

TABLE 6(B):

FREQUENCY DISTRIBUTION AS FOLLOWS

Age Group Frequency Percentage

1 48 15.1 2 150 46.1 3 96 13.0

4 29 9.0

6(C) DISTRIBUTION OF SEX IN PATIENTS [n = 323]

In the primary data collection. Individual Surgeries were entered. While analysing for

Frequency of distribution and Risk Association subsequently they were grouped broadly

under 6 categories

Table 6( C) Sex Distribution

Sex Frequency Percent

Male 255 78.8

Female 68 21.2

Total 323 100

6(D) TYPE OF SURGERY PERFORMED [n = 323]

Type of laparotomy were broadly categorized into 6 groups depending upon the

aetiology

Category 1 – intestinal obstruction

Category 2 – hollow viscous perforation

Category 3 – upper GI surgery ( gastrectomy, TV GJ, Cholecystectomy)

Category 4 – colorectal surgeries( LAR/APR)

Category 5 – other gynaecological process

TABLE 6(D)

DISTRIBUTION OF SURGERY PERFORMED.

Group Frequency Percentage

1 95 29.4 2 123 38.0 3 46 14.3 4 29 9.0 5 9 2.9 6 21 6.5

TABLE 6(E) TYPE OF SURGERY [n = 323]

TABLE 6(E) DISTRIBUTION OF SURGERY BASED ON WOUND CLASS

Type Frequency Percent

Clean 193 59.6

Clean

Contaminated 79 24.5

Contaminated 51 15.9

TABLE 6(F)

NATURE OF SURGERY [n = 323]

TABLE 6(F) – DISTRIBUTION OF EMERGENCY & ELECTIVE SURGERY

Nature Frequency Percent

Emergency 68 21.2

Elective 255 78.8

Total 323 100

The frequency of Emergency procedures as shown in Table 6(F) were 21.2% and that of

TABLE 6(G)

RISK FACTORS

They were categorized into 2 groups – General and Local / Specific.

6(G).1 DISTRIBUTION OF GENERAL RISK FACTORS [n = 323]

TABLE 6(G)1 DISTRIBUTION OF GENERAL RISK FACTORS

Present Absent

Risk Factor Frequency Frequency

(%) (%)

Anemia 42 (13.1) 281 (86.9)

Diabetes 16 (4.9) 307 (95.1)

Tuberculosis 4 (1.2) 319 (98.8)

Malignancy 21 (6.5) 302 (93.5)

As shown in table 6(G)1 most prevalent risk factor were anaemia followed by malignancy

and diabetes mellitus. Other factors tuberculosis was very low in incidence. Hence it was

TABLE 6(G)2

DISTRIBUTION OF LOCAL / SPECIFIC RISK FACTORS

[n = 323]

6.(G)2 – DISTRIBUTION OF SPECIFIC / LOCAL RISK FACTORS

Present Absent

Risk Factor Frequency Frequency

(%) (%)

UTI 20 (6.1) 303 (93.9)

URI 0(0) 323 (100)

LRI 21(6.5) 302 (93.5)

Table 6.(G)2indicates UTI and LRI were the most important risk factors followed by,

TABLE 6(H).

ADMINISTRATION OF PRE-OP ANTIBIOTICS [n = 323]

TABLE 6( H) FREQUENCY OF ADMINISTRATION OF PRE-OP

ANTIBIOTICS.

Pre-Op.

Antibiotics

Frequency Present

Not Given 195 60.4

Given 128 39.6

Total 323 100

Table 6(H) shows that 128 cases were given pre op antibiotics for the indications

6.(I) DURATION OF SURGERY [n = 323]

TABLE 6.(I)

DISTRIBUTION OF DURATION OF SURGERY

Duration Frequency Percent

< 1 hour 83 25.7

1 – 2 hours 144 44.5

>2 hours 96 29.8

As shown in Table 6(I) operations performed between 1-2 hrs were more. Comprises

6.(J). OPERATING SURGEON[n = 323]

TABLE 6.(J) :

CASE DISTRIBUTION BASED ON OPERATING SURGEON

Done by Frequency Percent

Chiefs 54 16.7

Assistant Professor 169 52.2

PG 100 31.2

Table 6.(J) shows that 169 cases ( 61 %) of the cases were performed by assistant

professors, trainees performed 100 cases and chiefs performed 54 cases (16.3) . Most of

the cases performed by chief were ASA category 3, contaminated and those patients with

6.(K) UNIVARIATE ANALYSIS FOR RISK FACTORS FOR SSI

TABLE 6(K) : RISK FACTORS FOR SSI

Sample Incidence

S.No Risk Factor Size Wound P value

Infection(%)

1. Sex 0.977

male 323 29/253(11.5)

Female 8/68(11.5)

2. Age 0.010*

Up to 20 0/48(0)

21-40 13/148(8.8)

41-60 323 17/96(17.8)

60 and above 7/29(22.7)

3. Surgical procedure 0.000*

1 8/94(8.3)

2 9/122(7.5)

3 323 10/46(22.9)

5 0/9(0)

6 9/21(43.8)

4.

Type of

surgery

0.052

Clean 25/191(13.0)

Clean 323

Contaminated 3/79(3.3)

Contaminated 9/51(17.9)

5.

Nature 0.312

Emergency 11/68(15.4)

Elective 323 26/254(10.4)

6.

Anemia

0.424

Present 7/42(15.6)

Absent 30/279(10.8)

7.

Diabetes

0.633

Yes 3/16(16.7)

No 323 34/305(11.2)

Yes 0/4(0)

No 323 37/317(11.6)

9.

Malignancy

0.024*

Yes 7/21(31.3)

No 323 30/300(10.0)

10. UTI 0.018*

Yes

323 7/20(33.3)

No 30/301(10.0)

11.

LRI 0.004*

Yes 323 8/21(50)

6.(L).1 ANALYSIS OF INFECTED CASES [n = 28] DAY OF DETECTION OF WOUND INFECTION

TABLE 6.(L)1

DISTRIBUTION OF DAY OF DETECTION OF WOUND INFECTION

Day of Detection Frequency Percent

2 4 10.7

3 7 17.9

4 10 28.6

5 8 21.4

6 5 14.3

7 1 3.6

8 1 3.6

Total 36 100

As shown in Table 6.(K)1 POD 4 was the day in which highest no. of wound infections

6.(L)2 METHOD OF DETECTION

TABLE 6.(L)2 : DISTRIBUTION OF METHOD OF DETECTION

Method Frequency Percent

Clinical 9 25

Clinical and Microbiological 27 75

Microbiological 0 0

Total 36 100

Table 6.(L)2 shows that clinical and microbiological detection combinely showed a

frequency of about 75% combining with clinical alone ( 25%) there was no case detected

6.(L)C. ORGANISM CULTURED FROM WOUND (n = 21)

TABLE 6.(L)C : DISTRIBUTION OF ORGANISMS ISOLATED

Organism Frequency Percent

No Growth 1 3.5

Staph & Strep species 8

28.6

Klebsiella &

Escherichia

9 32.1

Pseudomonas 4 14.3

Citrobacter Spp. 3 10.7

Others

3 10.7

Total 28 100

As Table 6(L)3shows Escherichia & Klebsiella spp. Show a high frequency distribution.

14.3 10.7 10.7 ORGANI 3.5 32.1 7

ISM ISOLAATED

28.6 _N S K E P C O

No Growth taph & Strep s Klebsiella &

scherichia Pseudomonas Citrobacter Spp Others

species

6.(L)D OUTCOME OF WOUND INFECTION [n = 28]

6.(L) D: DISTRIBUTION OF OUTCOME OF WOUND INFECTION

As shown in Table 6(L)D around 93% of SSI cases resolved without any

sequel, whereas 2 cases went for other complications.

Outcome Frequency Percent

Resolved 34 92.9

Not-Resolved 2 7.1

DISCUSSION

7(A) INCIDENCE OF SSI (SURGICAL SITE INFECTION)

7.(A).1 Overall Incidence of SSI

The incidence of SSI in the present study is 11.4% which is

High as compared to other studies.

Table 7(A) : Comparison of Incidence of wound infection

CLASS INFECTION

STUDY OVERALL RATE (%)

I II III

MPLS – VAMC _{2.5 1.4 2.8 8.4}

Foothills Hospital _{4.7 1.5 7.7 15.2/40}

NAS – NRC _{7.5 5.1 10.8 16.2/29}

SENIC _{4.1 2.9 3.9 8.5/12.6}

COMPARISION OF OVERALL INCIDENCE OF SSI

2.5

4.7

7.5

4.1

11.4

0 2 4 6 8 10 12

INCIDENCE- CATEGORY WISE

1.4 1.5

5.1

2.9

13

0 2 4 6 8 10 12 14

MPLS – VAMC Foothills Hospital NAS – NRC SENIC PRESENT

0 2 4 6 8 10 12 2.8

MPLS – VAAMC Footh

7.7

hills Hospital

clean

10.8

NAS – NR

n

contam

0 2 4 6 8 10 12 14 16 18 20 8.4

MPLS – VAMC

1

C Foothill

15.2

s Hospital

Con

16.2

NAS – NRC

7(A)2 INCIDENCE OF WOUND INFECTION CATEGORY WISE

• The Incidence among clean contaminated group(3.3%) and contaminated

group(17.9%) categories compares similar to other studies ; but Incidence of clean

case group were (13.0%) is very high which may be the reason for high overall

incidence (11.0%).

• The reason behind this issue may be due to observer bias , Intern &Trainee were

first to examine the wound, they might have over diagnosed rate of SSI. Especially

in clean cases where pre or intra opetrative antibiotics were not given 

7(B) RISK FACTORS FOR WOUND INFECTION

7.(B)1. AGE AND SEX:

In our study the incidence among both male and female were almost similar.(11.4 % vs

11.5%) hence it is well proved that sex does not appear to be a risk factor for

development for SSI. As other studies age has a strong positive correlation with

less than 20 years vs patients more than 6 years with a p value of 0.01. which is

statistically significant.

7.(B)2. SURGICAL PROCEDURE:

Surgical procedure were arranged into 6 groups based on the aetiological factor behind

laparotomy. These surgical procedure categories had a strong correlation with

development of SSI with a p value of 0.000. among the 6 categories ileostomy or

colostomy reversal had a high incidence of SSI. The underlying factor may be faecal

contamination, malignancy and malnourishment following incomplete absorption of food.

In category 3( upper GI surgeries, gastrectomy TV GJ, ) wound infection rate were high

since many of the cases were having malignancy. There are very few SSI in

gynaecological related laparotomy may be due to sterile nature of ovarian or uterine

pathology.

7.(B) 3 TYPE OF PROCEDURE (BASED ON WOUND CLASS)

In our study wound category based on wound contamination is both an important risk

0.0152, it is not statistically significant risk factor, which might be due to discrepancy in

incidence among clean cases compared with other studies.

7.(B)4 NATURE OF SURGICAL PROCEDURE

Emergency surgery shows higher rate(15.4%) of SSI as compared with elective

procedure(10.4%). The results are expected since many of the emergency cases are

having clean contaminated class and also have pre existing illness such as LRI or UTI. As

Garibaldi et al. the emergency procedures by themselves do not function as a risk factor.

Our studies also shows parallel results in this regard.(19)

7(B).5 ANALYSIS OF ANEMIA, DIABETES MELLITUS, TUBERCULOSIS

AND MALIGNANCY AS RISK FACTORS.

Among the variables mentioned Malignanc is havinh striong association as a risk factor

7.(B).6 ANALYSIS OF UTI, LRI, FOCUS OF INFECTION AS RISK FACTOR.

Among UTI incidence wer (33.3 %), LRI (37.5%) with p value of 0.018, 0.004

respectively showed a strong association for development of SSI which is statistically

very significant

7.(B)7 DURATION OF SURGERY

In many studies SSI is directly proportional to rate of duration of surgical procedure . In

our study higher incidence is seen in surgeries performed between 1-2 hr than in other

categories. It would be better to remember that in our study duration was set arbitrarily,

which was not on the lines of recommended in recent literature. The observations not

fully support above said statement as there is less no.of cases done in more than 2 hrs.

Also evaluates 0.342 . anyhow increase in incidence among less than 1 hr group to 1-2 hr

group from 9.6 to 14.7% shows that duration of surgery is significant risk factor for

7.(B)8 OPERATING SURGEON

Our study shows higher incidence of SSI in surgeries perfiormed by chiefs as compared

to other groups with a p value of 0.487. it is both statistically insignificant and most of the

surgeries done by chiefs are coming under high risk surgeries like patients with

pre-existing illness, ASA categpory 3, malignancy, grossly contraminated cases, etc. the

surgeries done by trainees shows least incidence( 8.1%) maybe due to uncomplicated

cases they are doing.

7.2.9 ANTIBIOTICS:

According to our study preoperative antibiotic exposure group showed a strong

association with development of SSI(p value 0.015) the reason is supposed to be due to

antimicrobial resistance to antibiotics or also due to inadequate infection control

7.(C)ANALYSIS OF INFECTED CASES:

Which include day of detection, method of detections, organisms isolated and outcome of

7.(C).1 DAY OF SSI DETECTION

Around half of the cases are diagnosed on day 4. 26.6% and day 5 . most of the cases are

detected in first week of surgery. The most delayed SSI ditection was on POD 8

7(C).2 METHOD OF DETECTION

In our study we have used 3 ways for diagnosing SSI as in table 6(L)2 there is no clinical

case categorized under microbiological means alone. Clinical diagnosis was upto 25% of

the cases. There is also an expected inter observer bias in clinical detection of SSI s we

have explained earlier.

7(C).3 ORGANISMS ISOLATED

27 out of 36 case were found to have positivity to micro organisms. The result showed

following observations. Klebsiella, e-coli species were positive about 1/3rd cases and

staph and strep comprised about 28.6%. combining all these 4 organisms comes about

7.(C)4 OUTCOME OF SSI

In our study 34 out of 36 cases resolved without any sequele. In other 2 cases one

got septicaemia and another got enterocutaneous fistula. Limiting factor in our study is

diagnosis and observations made by a group of people. Diagnosing a wound infection

may have high interobeserver bias which may leads to statistical variations. Which is

more pronounced while diagnosing SSI in clean cases, even before diagnostic criteria

written earlier developed fully, we are forced to start antibiotics to treat development of

infection. This overdiagnosis purely on clinical grounds maybe the cause of certain

results in our study, such as increase incidence among week cases, advancement in day of

SUMMARY AND CONCLUSION

• Our study on post laparotomy wound infection was carried out for a span of one

year duration on a sample size of 323 patients an overall incidence of 11.4 % (36

out of 323) had SSI classwise categorization were bbased on National Reasearch

Council Adhoc Committee showed 13% clean, 3.3 % clean contaminated and

17.9% in contaminated cases.

• Factors which influence wound infection shows the following observations in our

study.

• The factors considered are age , sex ,co morbidities , type of surgery, nature of

surgery, duration of surgery, aetiology for laparotomy and performing surgeon.

• Sex was not having a difference in incidence rate in development of SSI.(incidence

• Increasing age showed a strong association for the development of SSI. Under age

20 the development of SSI was 0% whereas age over 61 has an incidence of 22.7%

with a p value of 0.01, which is statistically significant.

• 2 categories of pre-existing illness we have studied which includes general and

local/specific factors. Anaemia, TB ,malignancy and diabetes were the general

factors we analysed.

• Malignancy showed a high incidence of SSI.(31.3%) as compared with other

group (10%) with a p value of 0.024. which is statistically significant. Diabetes,

TB , anaemia did not show any statistically significant association for development

of SSI.

• UTI and LRI were categorized under local/ specific factors, analysed as a risk

factor for development of SSI. They showed a p value of 0.018, 0.004

• Various aetiological factors which result in laparotomy were having a p value of

0.000 showed that it is/ statistically significant risk factor for development of SSI.

Highest incidence is seen in category with ileostomy / colostomy reversal group

which maybe due to malnouriushment by underlying malignancy or reduced food

absorption due to inadequate length of bowel and fecal cointamination. Category

3( upper GI surgeries, gastrectomy TV GJ, ) wound infection rate were high since

many of the cases were having malignancy.

• There are very few SSI in gynaecological related laparotomy may be due to sterile

nature of ovarian or uterine pathology.

• When we are comparing emergency surgery vs elective surgery incidence of

wound infection were 15.4 vs 10.4. the analysis had a p value of 0.312 which was

• Regarding duration of surgery and performing surgeon did not show any positive

correlation with development of wound infection because their p value were 0.342

and 0.487 respectively.

• We found incidence of SSI in clean ,clean contaminated and contaminated were

13%,3.3%, 17.09% respectively. Bias in overdiagnosing wound infection is

supposed to be the reason for this variation.

• Antibiotic resistance and inadequate control of previous infections such as LRI and

UTI maybe the reason why the patient with preoperative and perioperative cases

had a strong association with SSI (p value of 0.015 which is statistically

significant).

• Out of 36 infected cases 34 had complete resolution with pour treatment . POD 4

was the day on which most of the infections were diagnosed, diagnosis were made

common organisms identified as aetiological agents in development of SSI were e

CONCLUSION

• Our study shows a group wise incidence ratio of SSI were 13.0%, 3.3%, 17.9% in

category 1 (clean) , category 2( clean-contaminated) and category 3 (contaminated

& dirty cases respectively). And combined incidence ratio is 11.4%

• Variables like sex , wound category, nature of surgery (emergency / elective) ,

surgery duration, TB (pulmonary tuberculosis) , Diabetes Mellitus or Anaemia did

not associate strongly with wound infection.

• The variables which showed a strong correlation with SSI are increasing age, type

of surgery, associated malignancy ,UTI(urinary tract infection) & LRI (lower

respiratory tract infection)

• Out of Infected group [N = 36]

• 92.9% had complete resolution, 7.1% had post SSI sequele

• Post operative day -4 recorded maximum SSI

• Similar to literature common bacterial agents are Staphylococcus and

BIBLIOGRAPHY

1.Maingot’s abdominal operations 12th edition, Page No. 3

2.Mangram AJ, Horan TC, Perlson ML, Guidelines for prevention of SSI, 1999

3.Gayness RP, Culver DH, Horan TC Et Al, SSI rates in US 1992-1998

4.Sabiston Textbook of Surgery The Biological Basis of Modern Surgical Practice,

20th Edition

5.Frantz MG, Robston MC, Steed DL Guidelines to Aid Healing of Acute Wound by

Decreasing Impediments of Healing. Wound Rep Reg 2008.

6.Pomposelli JJ, Baxter JK, 3rd, Babineau TJ, et al: Early postoperative glucose

control predicts nosocomial infectionrate in diabetic patients.

7.Ameracan Journal of Surgery, 1971- ;121, Seropian R, Reynolds BM Wound

Infection after preoperative depilator versus razor preparation.

8.Alexander JW. Fischer JE, Boyalian M. The influence of hair removal methods on

wound infection. Arch Surg 1983 ; 118 : 347.

9.Cruse PGE Foord F The Epidemiology of Wound Infection: A 10 year prospective

study of 6-9 Wounds

10. Edwards LD, The epidemiologist of 2056 remote site infections and 1966

surgical wound infection occurring in 1865 patients. A four year study of 40,923

operations at Rush-prebysterin – St.Lukes Hospital Chicag. Ann Surg, 1976 ; 184 :

11. Lewis RT. Wound infection after gastroduodenal operations, A 10 year review.

Can J surg, 1977;20 : 435.

12. Claesson BEB, Holmlund DEW. Predictons of intra operative bacterial

comtamination and post operative infection in elective colorectal surgery. J

Hosp.Infect 1988 ; 11: 227.

13. Dineen P, An evaluation of duration of the surgical scrub. Surg Gynecol Obstet

1969;129:1181

14. Garibaldi RA, cushing D, Lorer T. Risk factors for Post operative infection.

Am J Med 1991 ; 91 (Suppl 3B) : 1585.

15. Culver Dh, Horen TC, Gaynes RP. Surgical wound infection rates by wound

class, operative procedure, and patient risk indes. Am J Med, 1991; 91 (Suppl

3B) : 152 S.

16. Page CP, et al. Antimicrobial Probphylaxis for surgical wounds: guidelines for

clinical care. Arch Surg 1993 ; 79 : 128.

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BOOK REFERENCES

1. Maingot’s Abdominal Operations 12th Editions

2. The Washington Manual of Surgery 7th Edition

3. Bailey and Love’s Short Practice of Surgery

4. Sabiston Textbook of Surgery 20th Edition

5. Schwartz’s Principles of Surgery

6. Fischer’s Mastery of Surgery

7. Trauma By Kenneth L Mattox 7th edition

APPENDIX

PROFORMA : WOUND – INFECTION

INFECTED / NOT INFCTED

AGE : NAME :

SEX :

ADDRESS : OCCUPATION :

HOSPITAL NO : SOCIO-ECONOMIC

STATUS :

CLINICAL SUMMARY AND DIAGNOSIS :

INVESTIGATIONS :

Hob% : Blood Sugar :

Urine – Others :

RISK FACTORS :

GENERAL YES NO

ANEMIA ( ) ( )

DIABETES ( ) ( )

TUBERCULOSIS ( ) ( )

MALIGNANCY ( ) ( )

SPECIFIC / LOCAL YES NO

UTI ( ) ( )

URI ( ) ( )

SURGERY PROPOSED

SURGERY PERFORMED

TYPE OF SURGERY:

CLEAN ( )

CLEAN-CONTAMINATED ( )

CONTAMINATED/DIRTY ( )

NATURE OF SURGERY:

ELECTIVE ( )

EMERGENCY ( )

PRE-OPERATIVE ANTIBIOTICS:

GIVEN ( )

NOT GIVEN ( )

PER-OPERATIVE

DURATION OF SURGERY:

<1 Hrs. ( )

1-2 Hrs. ( )

>2 Hrs. ( )

PERFORMED BY:

CHIEFS ( )

ASST. PROFS. ( )

TRAINEES ( )

ANTIBIOTICS:

USED ( )

NOT USED ( )

POST OPERATIVE:

INFECTED ( )

FOR “INFECTED” CASES ONLY

DAY OF DETECTION:

METHOD OF DETECTION:

CLINICAL ( )

MICROBIOLOGICAL ( )

BOTH ( )

ORGANISMS GROWN IN CULTURES:

SENSITIVITY PATTERN TO

ANTIBIOTICS:

OUTCOME:

RESOLVED ( )

NOT RESOLVED ( )

ANTIBOITICS

USED

1

NOT-USED

0

POST-OPERATIVE

METHOD OF DETECTION

CLINICAL

1

MICROBIOLOGICAL

2

CLINICAL & MICROBIOLOGICAL

OUTCOME

RESOLVED

1

NOT-RESOVED

0

ORGANISM GROWN IN CULTURE

NO GROWTH

0

STAPHLOCOCCUS AND STREPTOCOCCUS SPECIES 1

ESCHERICHIA AND KLEBSIELLA SPECIES 2

PSEUDOMONAS AEURIGINOSA

3

CITROBACTER DIVERSIS

4

OTHERS

*CODING

NAME

CODE

WOUND

INFECTED

1

NOTINFECTED

0

SEX

MALE

1

FEMALE

SURGERY DONE

TYPE OF SURGERY

CLEAN

1

CLEAN-CONTAMINATED

2

CONTAMINATED

NATURE OF SURGERY

EMERGENCY

1

ELECTIVE

2

RISK FACTORS

PRESENT

1

NOT-PRESENT

0

PRE-OPERATIVE ANTIBIOTICS

USED

1

NOT-USED

0

DURATION

<1 HOUR

1-2 HOURS

2

>2 HOURS

ABBREVIATIONS USED

SSI Surgical Site Infection

NNIS National Nosocomial Infection Control

S.AUREUS Staphylococcus aureus

E COLI Escherichia coli

CT Computerised Tomography

LRI Lower Respiratory Tract Infection

URI Upper Respiratory Tract Infection

UTI Urinary Tract Infection

DM Diabetes Mellitus