|Year : 2022 | Volume
| Issue : 2 | Page : 186-189
Utility of surgical apgar score in predicting morbidity and mortality in post-operative patients
TG Jithu1, MH Firoz Khan1, Kusuma Halemani2, KN Vijayan1
1 Department of General Surgery, KIMSHEALTH Hospital, Thiruvananthapuram, Kerala, India
2 Department of Anaesthesiology, KIMSHEALTH Hospital, Thiruvananthapuram, Kerala, India
|Date of Submission||22-Nov-2022|
|Date of Decision||28-Nov-2022|
|Date of Acceptance||02-Dec-2022|
|Date of Web Publication||30-Jan-2023|
Dr. T G Jithu
Department of General Surgery, KIMSHEALTH Hospital, Thiruvananthapuram - 695 029, Kerala
Source of Support: None, Conflict of Interest: None
Introduction: Predicting complications forms an essential part of risk management in surgical practice. Recognising patients at high risk of developing a complication will contribute substantially to the quality of surgery and financial burden. This study aimed to assess the utility of surgical Apgar score in assessing morbidity and mortality in post-operative patients. Materials a Methods: The surgical Apgar score was calculated on all patients between 16 and 75 years undergoing surgery that required intensive perioperative monitoring in the general surgery department and correlated the score with the patient's outcomes in the form of complications, including death within 30 days of surgery. Results: Among the 214 patients, more than 70.6% of the patients were in the age group of above 40 years. The relationship with the lower surgical Apgar score is significant in terms of predicting post-operative complications (P < 0.001). The most common comorbidities were hypertension (43.9%) and diabetes mellitus (DM) (16.4%). However, the presence of DM and coronary artery disease influenced the outcome significantly. Emergency surgeries were associated with significantly more risk of complication within 30 days of surgery. Prolonged intensive care unit care and ventilation support, sepsis and pneumonia are the major set of post-operative complications in our study. A low surgical Apgar score is associated with an increased likelihood of complications. Conclusion: The surgical Apgar system is effective in stratifying patients into high-risk and low-risk groups and anticipating post-operative complications.
Keywords: Perioperative complications, post-operative complication, surgical Apgar score
|How to cite this article:|
Jithu T G, Firoz Khan M H, Halemani K, Vijayan K N. Utility of surgical apgar score in predicting morbidity and mortality in post-operative patients. Kerala Surg J 2022;28:186-9
|How to cite this URL:|
Jithu T G, Firoz Khan M H, Halemani K, Vijayan K N. Utility of surgical apgar score in predicting morbidity and mortality in post-operative patients. Kerala Surg J [serial online] 2022 [cited 2023 Mar 24];28:186-9. Available from: http://www.keralasurgj.com/text.asp?2022/28/2/186/368601
| Introduction|| |
The surgical team and health-care providers strive to provide a consistently low incidence of major complications for patients undergoing any given surgery. Predicting any complication forms an essential part of risk management in surgical practice. Recognising patients at high risk of developing a complication will contribute substantially to the quality of surgery and financial burden.
A 10-point Surgical Apgar Score was determined by Gawande et al. to provide surgeons with a simple, objective and direct method of rating and predicting the outcomes. To derive the score, more than two dozen parameters were collected in the operating room and were assessed. Just three intraoperative variables remained independent predictors of major post-operative complications and death, lowest heart rate, lowest mean arterial pressure and estimated blood loss. A score derived from these three predictors has proved beyond doubt as a strong predictive model for categorising the patients at risk of major post-operative complications and death in general and vascular surgery. As this scoring system requires data that can be collected immediately on the completion of surgery in any setting, regardless of resource and technological capacity, it is the simplest available scoring system for assessing the risk and predicting the outcome.
Due to its simplicity, availability in real time, being immediately applicable for clinical decision-making and inexpensive, Apgar score can be termed as a powerful tool for the early detection of complications. After accounting for pre-operative risk, the surgical Apgar score remains a significant predictor of post-operative complications. Due to the immediate feedback, it would help the surgical team in categorising the patients in need of intense post-operative monitoring and care from those who pass an uncomplicated course. In this study, we will evaluate the predictive ability of the surgical Apgar score in general surgery.
| Materials and Methods|| |
The study aimed to assess the utility of surgical Apgar score in assessing morbidity and mortality in post-operative patients. We calculated the surgical Apgar score for patients undergoing surgery in the general surgery department and correlated the score with the patient's outcomes in the form of complications, including death within 30 days of surgery.
It was a prospective, observational study from July 2015 to June 2017 on all patients between 16 and 75 years from our tertiary care centre who had undergone general surgical procedures (laparoscopic cholecystectomy, laparoscopic appendectomy, perianal, breast, thyroid, parathyroid and parotid surgeries, groin or umbilical hernia repair, skin or soft tissue and endovascular surgeries, complex alimentary or retroperitoneal surgeries such as colectomy and gastrectomy, open vascular, hepatobiliary and pancreas surgeries, open or laparoscopic bariatric, ventral or incision hernia repair, etc.) under general or regional anaesthesia that required intensive perioperative monitoring were included in the study. Patients undergoing surgery for trauma who had ongoing external blood loss, transplantation operation or endoscopic-only procedures, patients who required cardiopulmonary bypass/machine or were taking beta-blockers and surgeries under local anaesthesia not requiring intensive monitoring were excluded from the study.
A sample size of 214 patients was calculated. Sample size determination was done by:
Where z1-α/2 is the table value at 0.05 significance, i.e., 1.96, 's' is the standard deviation as determined by previous studies, which is 1.49, and 'd' is the allowable error of 20% (0.2).
Procedures were allocated into categories as follows: using estimated blood loss, lowest heart rate and lowest mean arterial pressure during the surgical procedure. The surgical Apgar score was calculated [Table 1].
Scores were categorised into 0–2, 3–4, 5–6, 7–8 and 9–10 for simplicity. Data such as lowest heart rate, lowest mean arterial pressure and blood loss during minor surgeries are noted intraoperatively and collected from the anaesthesiologists' records.
Estimated blood loss for major surgeries is calculated using the formulae:
Blood loss = [(EBV × (Hi - Hf))/((Hcti + Hctf)/2)] + (500 × Tu)
- Estimated blood volume is assumed to be 70 cm3/kg
- Hi and Hf represent pre- and post-operative haemoglobin
- Hcti and Hctf represent pre- and post-operative haematocrit and
Tu is the sum of autologous whole blood, packed red blood cells and cell saver units (Fresh Frozen Plasma (FFP), cryoprecipitate and apheresis) transfused.
Patients are followed up for the occurrence of any major complication or deaths within 30 days of surgery. The following events are considered major complications: acute renal failure, bleeding that requires a transfusion of four units or more of red blood cells within 72 h after surgery, cardiac arrest requiring cardiopulmonary resuscitation, coma of 24 h or longer, deep-vein thrombosis, myocardial infarction, unplanned intubation, ventilator use for 48 h or more, pneumonia, pulmonary embolism, stroke, wound disruption, deep or organ-space surgical site infection, sepsis, septic shock, systemic inflammatory response syndrome and vascular graft failure. Post-operative complications of Clavien Class III and greater [Figure 1], i.e., those that require surgical, endoscopic or radiological reintervention for diagnosis of complications and those requiring intensive care admission. Superficial surgical site infection and urinary tract infection are not considered major complications.
|Figure 1: Clavien classification of grading the post-operative events based on the severity of complications|
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| Results|| |
Among the 214 study population, males accounted for 37.4% (80) and females 62.6% (134). Age wise, 14.4% (30) were <30 years of age; 15.4% (33) were between 30 and 40 years; 22.9% (49) were between 40 and 50; 24.8% (53) were between 50 and 60 years; 14.5% (31) were between 60 and 70 years and 8.4% (18) were more than 70 years.
Prolonged intensive care need or ventilator support was the most commonly observed post-operative complication, followed by sepsis. Six patients had miscellaneous complications (indicated by the column 'others'), which included the need for transfusion greater than 4 units of blood, cerebrovascular events and re-exploration.
The most common comorbidities noted were hypertension (43.9%), diabetes mellitus (DM) (16.4%), cancer (9.3%), coronary artery disease (CAD) (8.5%), chronic obstructive pulmonary disease (COPD) (4.2%), obesity (3.3%) and other miscellaneous (8.4%) [Figure 2].
The presence of DM and CAD influenced the outcome compared to the rest of the comorbidities as indicated by the significant P value [Table 2].
81.8% of surgeries were elective, while 18.2% of surgeries were emergencies amounting to around 1/5th of the total cases. Emergency surgeries were associated with more risk of complication within 30 years of surgery which is statistically significant (P < 0.001).
The maximum of patients belonged to a score of 9–10, where the post-operative complications were nil. The minimum score was 0–2, which had been observed in one patient who succumbed to death. The significant P value suggested that the lower Apgar score was associated with the increased likelihood of post-operative complications [Table 3].
|Table 3: Surgical Apgar score with respect to complications and 30-day mortality|
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| Discussion|| |
A simple surgical score based on estimated blood loss, lowest heart rate and lowest mean arterial pressure during an operation provides a meaningful estimate of the patient's condition and rate of major complications and death after surgery.
About 37.4% of the surgical cases in our study were male patients and 62.6% were female patients. Most of the studies on the Apgar score by Gawande et al. and Regenbogen et al. show a female preponderance of cases of 56% to 65% in different cohorts of study. However, there has been no association between gender, score and prognosis in these studies.
More than 70.6% of the patients were in the age group of above 40 years. Only 29.4% of patients belonged to the age <40 years. The elderly population (age >60 years) constituted around 23% of the total cases. The similar age distribution, with an average of 55.3 years to 63.6 years, has been noted in previous studies. Gawande et al. showed significantly high rates of major complications of 16% with a mean age of 64.2 years.
The most common comorbidities noted were hypertension (43.9%), DM (16.4%), cancer (9.3%), cardiac disease (8.5%), COPD (4.2%), obesity (3.3%) and miscellaneous (thyroid dysfunction, asthma, stroke, etc., in 8.4%). DM and cardiac disease were significantly associated with post-operative complications and death in this study. Other studies also indicate similar comorbid conditions associated with poor prognosis. Some of the additional risk factors which have been noted are the American Society of Anaesthesiologists class >3, underweight (body mass index [BMI] <18.5), open wound, weight loss >10% in 6 months, ascites and gangrene.
No significant difference in the occurrence of the complications or 30-day mortality was noted with hypertension, cancer, COPD, obesity and other comorbidities compared with Regenbogen et al. Gawande et al., where a cohort of 303 colectomy cases was analysed, do not show any significant correlation with BMI, cardiovascular disease, pulmonary disease, pre-operative sepsis, malignancy or blood transfusion.
81.8% of surgeries in this study were elective in nature. 18.2% of surgeries were emergencies amounting to around only one-fifth of the total cases. A study on emergency surgical admissions by Capewell showed that 46%–57% of all surgical admissions are emergency in nature. Of the 175 elective cases, one case had major complications, while of 39 emergency cases, eight had major complications, which are statistically significant.
Of the 214 patients, the majority of patients (167) had a surgical Apgar score of 9–10, followed by 38 patients having a score of 7–8. The lowest score of 0–2 was seen in one patient, and that patient succumbed to post-operative complications. The relationship between the lower surgical Apgar score is significant with respect to post-operative complications (P < 0.001). A similar result with a relative risk of major complication among patients who had low scores was 16.1 (95% confidence interval, 7.7–34.0, P < 0.0001), compared with those who had a high score, as noted in the study by Gawande et al.
The most common complication noted in the study was the need for prolonged intensive care/ventilation, followed by sepsis. Pneumonia, acute kidney injury, cardiac arrest, stroke, need for multiple units of transfusion, death, etc., were the other observed complications. The relative risk of predicting a major complication remains significantly higher in the subgroups of the Apgar score for emergency surgeries compared to its elective surgeries, where the statistical power is usually limited for the lowest scores. Gawande et al. showed a statistically significant result for emergency procedures. Other studies have shown complication rates of 43% and a mortality rate of 4% in emergency gastrointestinal procedures.
Wong and Knaus, on the APACHE III risk prediction model, have shown that the overall predictive accuracy of the 1st-day APACHE III equation within 24 h of intensive care unit admission following a major surgery would be given a risk estimate for hospital death that was within 3%.
The limitation of our study was that surgical Apgar tends to be more effective in predicting the outcome, especially in the emergency and major settings, as they tend to have a wider range of scores. Further study needs to be conducted on the emergency subgroups to make the scoring system more validated. The study inherently has its drawback, especially when it comes to the calculation of blood loss while calculating the Apgar score, as there is no particular method that is sure-shot in estimating the blood loss occurring in surgery. In this study, the blood loss during surgery is calculated using a pre-defined formula consisting of the patient's pre- and post-operative haemodynamic values, blood volume and units of whole blood/blood components transfused for major surgeries and from anaesthesiologist chart for minor surgeries. Hence, we always rely on indirect methods to calculate blood loss. The other limitation which remains in the study is the dominance of minor and elective procedures, which can be attributed to the sharing of cases with aligned super specialities which are there in a tertiary care set-up.
| Conclusion|| |
The surgical Apgar system can be considered an effective tool as a mode of communication between the surgeon, anaesthesiologist and the medical/paramedical team involved in patient care in stratifying patients into high-risk and low-risk groups and anticipating post-operative complications.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]