Introduction

Peritonitis is inflammation of the peritoneum and is most commonly due to a localized or generalized infection. Currently, peritonitis is organized into three divisions based upon the source and nature of microbial contamination. Primary peritonitis is an infection without any visceral perforation, usually from extra-peritoneal source and monomicrobial in nature. Secondary peritonitis follows an intraperitoneal source usually from the perforation of a hollow viscus. Tertiary peritonitis develops following treatment failure of secondary peritonitis. Despite advances in diagnosis, surgical technique, antimicrobial therapy and intensive care support, secondary peritonitis remains a potentially fatal affliction. Several scoring systems were developed to evaluate and compare the outcomes of treatment. In 1981, Knauss et al. developed the Acute Physiology And Chronic Health Evaluation Score (APACHE) based on 34 physiological parameters. APACHE II was later developed as a simplified clinically useful system using 12 physiological variables.₁, ₂

Aim Of The Study

The aim of the study was to compare the outcomes of secondary peritonitis using APACHE II score.

Material And Methods

This prospective study was conducted for a period of 12 months on 50 patients admitted as cases of secondary peritonitis in the Department of Surgery, Himalayan Institute of Medical Sciences, Dehradun, which is a major tertiary health care center in the state of Uttarakhand, India. All the patients clinically diagnosed as secondary peritonitis including abdominal trauma and patients of both sexes and all age groups irrespective of the duration of illness and etiology were included in the study.

Clinical evaluation as well as hematological, biochemical and radiological investigations were carried out to confirm the diagnosis.

The following acute physiological parameters of APACHE II score were assessed and recorded at the time of admission: Temperature (°C), Mean arterial pressure (mm Hg), Heart rate, Respiratory rate (non-ventilated), Oxygenation (PaO₂ in mmHg with FiO₂<O.5 record PaO₂), Arterial pH, Serum Sodium (mmol/l), Serum potassium (mmol/l), Serum creatinine (mg/dl), Haematocrit (%), White blood count. These values were scored in accordance to the APACHE II chart scoring for abnormally high or low range. The score ranged from 0 to 4 on each side of the normal value. Zero score represents a normal value; an increase to 4 indicates the extreme end of high or low abnormal levels. These parameters represent the Acute Physiological Scores (APS).₂

Age points for adults were included in the study as follows: <44=0, 45-54=2, 55-64=3, 65-74=5, >75=6. Age points were modified as follows for children: 15=0, 10-14=2, 5-9=3, 1-4=5, and <1=6.₂

Chronic Health Points (CHP) were added if the patient had a history of severe organ system insufficiency or was immunocompromised: 2 for elective post-operative patients; 5 for non-operative or emergency post-operative patients.

The Glasgow coma score (GCS) ranging from 3-15 was also assessed in the study.

APACHE II Score = Temp + MAP + HR + RR + paO₂ + pH + Na + K + Cr + HCT + WBC + (15-GCS) + Age points + CHP.₂ (TABLE-1)

Figure 1

Table 1: APACHE II Severity Of Disease Classification System

Patients were resuscitated with intravenous fluids along with correction of electrolyte imbalances. Broad-spectrum antibiotics cover was given to all the patients. All patients who were fit to withstand general anesthesia were subjected to exploratory laparotomy to evacuate the purulent material from the abdomen and to stop the source of infection. Bilateral flank drainage or conservative management was done to those who were unfit for surgery. Postoperative outcomes were assessed and compared with the APACHE II scores.

Results

The age of the patients ranged from 6-82 years with a mean of 38.12 years. The commonest presenting symptom was abdominal pain (100%), followed by distension of the abdomen (82%), constipation, vomiting and fever.

The most common cause of secondary peritonitis encountered in this study was perforation of the gastrointestinal tract, the commonest being perforation of the anterior wall of the first part of the duodenum (42%). (TABLE-2)

Figure 2

Table 2: Causes Of Secondary Peritonitis (n=50)

Exploratory laparotomy was done in 37 patients who were fit to undergo a surgical procedure after resuscitation. Bilateral flank drainage was done in 5 patients and 8 patients were put into conservative management because of too low general condition to withstand any kind of surgical intervention. (TABLE-3)

Figure 3

Table 3: Mode Of Management

On analysis of the postoperative complications encountered in the study in relation to APACHE II score, it was observed that wound infection was the most common morbidity (40%) in patients having a low score. Incidence of septicemia was higher in patients having higher APACHE II score. (TABLE-4)

Figure 4

Table 4: Distribution of Patients with Postoperative Complications according to APACHE II Score

The mean duration of hospital stay was shorter in patients having a low score. Further, in patients having an APACHE II score above 20, the duration of hospital stay decreased as most of the patients expired or left against medical advice. (TABLE-5) (FIG-1)

Figure 5

Table 5: Distribution of Patients according to APACHE II Score with Mean Hospital Stay

Figure 6

Figure 1

The patients who had a score between 0-9 had the most favorable prognosis and worst prognosis was seen with scores above 20. The lowest mortality was seen in patients with scores less than 20. (TABLE-6) (FIG-2).

Figure 7

Table 6: Distribution of Patients according to APACHE II Score with Outcome

Figure 8

Figure 2

The observed mortality rate was 67% in the group with scores of 25-29 which was comparable to the predicted mortality of 62.5%. (TABLE-7) (FIG-3)

Figure 9

Table 7: Comparison of Observed and Predicted Mortality in the Study

Figure 10

Figure 3

Discussion

APACHE II parameters have shown a stronger relationship to the outcome than previous groupings by anatomical criteria, cause, abnormality, age and chronic ill health.

The study by Adesunkanmi et al. showed an incidence of postoperative complications of 42.4% similar to our study with an incidence of 58%. Patients having higher APACHE II scores had higher incidences of postoperative complications.₃

The mean length of hospital stay following treatment in survivors was 17.4 days as compared to 18 days in the study by Bohen et al.₄ The mean length of stay of non-survivors was 8.2 days and these patients had higher APACHE II scores. In their study of colonic perforations, Komatsu et al. found that APACHE II scores of 19 or more were significantly related to poor prognosis, as seen in our study.₅

The mean APACHE II score among survivors in our study was 8 and amongst the non-survivors it was 22.4, comparable to the studies done by different other authors. Mortality is thus directly linked with higher scores.₄, ₆, ₇

This study also confirms the ability of APACHE II score to predict the mortality and morbidity rate in secondary peritonitis patients.₈, ₉

We have adapted the APACHE II scoring system to pre-treatment estimation of risk in patients with secondary peritonitis. Knaus et al. stated that physiological classification is more appropriate when assigned early in the course of disease, independent of the effects of the treatment.₂

Conclusion

APACHE II score, as measured before the treatment of secondary peritonitis, correlates significantly with the outcome of the disease with respect to both morbidity and mortality.

Correspondence to

Dr. Shantanu Kumar Sahu Assistant Professor, Department of General Surgery Himalayan Institute of Medical Sciences Swami Ram Nagar Post Doiwala Dehradun Uttarakhand, India Mob- 0-9412933868 Email- lntshantanu@yahoo.co.in