Surgical Apgar Score Predicts Post-Laparatomy Complications

Dullo M1, Ogendo SWO2, Nyaim EO2

1 − Kitui District Hospital

2 − School of Medicine, University of Nairobi

Correspondence to: Dr. Michael Dullo, P.O. Box 103241-00101, Nairobi, Kenya Email: micdullo@yahoo.com

Abstract

Introduction: The Surgical Apgar score (SAS) presents a simple, immediate and an objective means of determining surgical outcomes. The score has not been widely validated in low resource settings where it would be most valuable. This study aimed to evaluate its accuracy and applicability for patients undergoing laparatomy at Kenyatta National Hospital (KNH), Nairobi.

 

Methodology: Using intra-operative records, we calculated Surgical Apgar Scores for 152 patients during a 6-month study between March 2011 and August 2011. Our main outcome measures were the incidence of major postoperative complications and/or death within 30 days of surgery.

 

Results: The mean age of the patients evaluated was 35.18 years, range of 14 to 80 years. Most laparatomies were emergency procedures (86.8%) with mean duration for surgery of 131 minutes. The overall rate for major complications and mortality was 40.8% and 7.9% respectively. Common morbidities were superficial and deep wound infection, anastomotic leakage and wound dehiscence. The mean SAS for patients with complications was lower (4.0) compared to those without (5.73) (p<0.001). Patients categorised as high risk had a 58.3% complication rate compared to low risk patients with 16.6 % (p=0.04). These outcomes compare favourably with other studies. The SAS demonstrated good predictive accuracy for post-operative morbidity (ROC area under the curve of 0.796, CI 0.727-0.865).

 

Conclusion: This study confirms the SAS as adequate in stratification of post-operative risk of major complications following laparatomy in our setting with good predictive accuracy.

Introduction

Peri-operative risk stratification of mortality and morbidity is important in the provision of health care to ensure appropriate resource allocation and informed decision making (1). Many risk-scoring systems are not easily calculated at the bedside; requiring numerous data elements including laboratory data(2).Thus, surgical teams do not apply them routinely for their patients(2).

 

Among currently available systems for surgical patients, the SAS stands out as holding promise for routine application in low resource settings(1). Modeled after the Apgar score in obstetrics, this ten-point model entered surgical practice in 2007(3). It is a simple, immediate and an objective means of determining surgical outcomes, using data available in most settings. The score is effective in predicting the risk of major postoperative complications thus prompting preventive counteractions. The score’s components capture elements of the overall patient condition, extent of the surgical insult and ability of the team to respond to and control hemodynamic changes during a procedure(4) (Table 1).

 

Click to view table 1

 

Criticism of this scoring system is that operative blood loss can be subjective although the wide categories utilised allow for reasonably accurate estimation (5,6).

 

 

Though validated for many procedures and in several countries in the west, few studies have been conducted in Africa where patient demographics and the clinical environment are different (7). The aim of this study is to evaluate the applicability and accuracy of the SAS in stratifying post-operative risk in patients undergoing laparatomy at the Kenyatta National Hospital (KNH).

 

Material & Methods

This was a 6 month, hospital based, single centre observational study at KNH, Nairobi, from March 2011 to August 2011. All admitted patients over 13 years of age undergoing laparatomy under general anaesthesia were eligible. Exclusion criteria included patients declining participation, undergoing concurrent major procedures on other body regions within 30 days, established metastatic and un-resectable tumours, mini-laparatomy and laparoscopic procedures.

 

Data collected included patient demographics, intra-operative diagnosis, duration of surgery, data relevant to the SAS calculation as above and development of major complications. The primary end-points were major complications and death within 30 days of surgery as per definitions given by Copeland et al(9). Patients were subsequently grouped into three categories based on their SAS for purposes of assessing risk stratification.

 

We performed all analyses using the SPSS Statistics, version 17.0.1(IBM Armonk, New York, USA). P values were generated using T test for means, Chi square test for comparison of proportions, analysis of variance (ANOVA) and where applicable Fischer’s exact test. P values < 0.05 were considered statistically significant.

 

As a measure of discrimination, we constructed receiver operating characteristic curve and calculated the area under the curve for the SAS. Area under the ROC is interpreted thus; .50-.75 = fair, .75-.92 = good,

.92-.97 = very good and .97-1.0 = excellent.

Results

We recruited a hundred and fifty four patients into the study. Two patients absconded and were lost to follow leaving 152 patients for assessment. There were 114 (75%) males giving a male: female ratio of 3:1. Age range was 14 to 80 years with a median of 31 years. The average age for males was 36.16 years compared to 32.24 years for females (p=0.163).

 

Emergency laparatomies constituted 86.8% and elective procedures 13.2%, (p=0.579). The commonest reason for laparatomy was penetrating abdominal injury (18.42%). Intestinal obstruction and peritonitis constituted (17.11%) each, perforated peptic ulcer (11.84) and other causes (11.84%). Others included renal calculi, stomach cancer, liver abscess, liver cyst and colonic cancer. Mean duration of surgery was 131.1 min (Range 60 to 300 minutes). Fifty patients suffered major complications during follow up (40.8%). Commonest complication was deep wound infection followed by anastomotic leakage and superficial wound infection (Table 2).

 

Click to view table 2

 

Females had more complications than males (63.2% versus 33.3%). Emergency laparatomies suffered more complications compared to elective cases, 43.9% versus 20%. Surgery of more than 120 minutes resulted in 68.6% complication rate compared to 26.7% for shorter procedures (Table 3). Twelve patients died (7.9%). The relationships between occurrence of complications and gender, setting of laparatomy, age and duration of surgery were all statistically significant(Table 3).

 

Click to view table 3

 

Click to view table 4

 

The SAS ranged from one to nine with a mean of 5.03 (median 5). Mean SAS for males was 5.28 and females 4.26 (p=0.001). Based on SAS, 31.6% of patients fell under the high-risk category, 59.2% medium and 9.2%