Life expectancy in emergency abdominal surgery has increased, including among older patients. However, regardless of age, emergency surgery is associated with a 3- to 10-fold increased rate of operative mortality; emergency colorectal surgery has a 9-fold increased risk of death.(7)(8) A previous study found that age is not an absolute contraindication in standard colorectal surgery; however, postoperative complications, mortality, and morbidity increase with age because of low physiological reserve and pre-existing comorbidities, which affect patient outcome.(9) Acute Care Surgery is a service system for emergency general surgery in our tertiary center, Ramathibodi Hospital, with guarantees of patients being attended within 30 minutes after consultation, time to an OR within 180 minutes, and advanced surgical critical care for postoperative intensive care. Using this system, we can improve the number of non-trauma cases and patient outcomes.(1) In this study, we sought to identify risk factors of mortality and morbidity in older patients undergoing emergency colorectal surgery, with the aim to identify modifiable risk factors and improve patient outcomes.
Regarding our results, comorbid heart disease was associated with a 7.6-fold increased risk of death (p = 0.022), leading to postoperative myocardial infarction in 1.09%, congestive heart failure in 6.52%, and arrythmia in 2.17% of patients. In this study, comorbid heart disease was present in 50% of patients who died. This reflects that comorbid heart disease is an unmodifiable risk factor, and preparation of these patients in emergency settings is sometimes limited. These patients require transfer to the ICU postoperatively for close monitoring. Our results showed a postoperative ICU requirement in 28.89% of patients; by indication, rates were 4.35% for comorbid heart disease and 16.67% for postoperative death from a cardiogenic cause. A previous study among octogenarians showed a 16% probability of death from cardiovascular disease, but this was not statistically significant; neurological comorbidity had a 4-fold increased risk of death.(7) Neurological comorbidities, such as stroke or even preoperative use of anticoagulants or antiplatelets, were not associated with an increased risk of death in our study.
Our service encourages an ERAS protocol for postoperative early ambulation and assessment of preoperative VTE risk using Caprini DVT risk score in every patient, to prevent adverse events of postoperative VTE. A previous report of a VTE prophylaxis benchmark for general surgery showed that VTE prophylaxis can reduce the incidence of pulmonary embolism, which can reduce mortality from 1.1–0.5% (p < 0.01).(12) Our study showed significant differences in Caprini risk score between patients who died and survivors, 5 and 4, respectively (p = 0.042). A score of 4–5 indicates a moderate to high risk of postoperative VTE. We therefore use intermittent pneumatic pressure in all patients intra- and postoperatively; however, we do not administer unfractionated or low-molecular-weight heparin owing to the risk of intraoperative bleeding. This prophylaxis protocol led to an incidence of death from pulmonary embolism in our study of only 1 among a total 92 cases of emergency colorectal surgery; high Caprini score was not associated with increased risk of death.
The most frequent cause of death was septic shock, with a rate of 50%, mainly caused by colorectal perforation (83.33%). Our results showed the initial clinical presentation of perforation is associated with a 16.5-fold increased risk of death (p = 0.013), especially if perforation occurred before hospitalization. With 67.03% clinical presentation of obstruction, we can prevent further perforation by not delaying surgery. In our study, the average operative time was 60 minutes. We found no further perforation with clinical obstruction, even in patients with obstruction and a competent ileocecal valve. Septic shock from perforation increases the risk of death but this may be modifiable with further development of fast-track surgical sepsis protocols to improve mortality and morbidity, which requires multidisciplinary team involvement. Calos et al. reported that septic shock was found 15.6% of emergency colorectal surgeries; in their study, this was the cause death in 5 patients but was not found to be a significant risk factor associated with death.(3)
The main cause of emergency colorectal surgery in our study population was colorectal cancer (83.52%), the same as in previous studies.(13) Lesions were more commonly located on the right side of the colon (41.57%) than on the left side (39.33%). In our patients with either right-side, left-side, or rectal lesions, we performed resection with primary anastomosis to avoid colostomy formation, except in patients with high levels of contamination from perforation and those with septic shock, in whom we performed Hartmann’s operation (12.64%). The most frequently performed operation was resection with primary anastomosis (71.26%) and anastomosis leakage (4.35%); these rates were lower than in previous studies. As seen in Table 3, anastomosis leakage was not associated with a significantly increased risk of death.(5) This might be because anastomosis leakage can now be treated in a minimally invasive manner, such as with percutaneous drainage, bowel rest, and antibiotics. Santos et al. reported that septic shock is the leading cause of death; in their study, the most common operations were Hartmann’s operation (85%), and the mortality rate was as high as 34%.(14) Compared with our results, even with increased risk of death in patients with septic shock, the overall mortality rate was only 6.52%. This implies that primary anastomosis is not a contraindication in emergency colorectal surgery. Pirrera et al. reported an anastomosis leak rate of only 6.2%, which confirms that older age is not a contraindication for primary anastomosis.(6) Calos et al. supported this with a low leakage rate in resection with primary anastomosis, even in emergency settings and older patients.(3) The differences in outcomes might be owing to the selection of patients for each operation; with primary anastomosis, patients with shock and high levels of contamination are avoided and Hartmann’s operation is performed. Santos et al. reported that septic shock was the leading cause of death, even when the most frequent surgery was Hartmann’s operation (85%).(14) This suggests that resection with primary anastomosis is not a contraindication in emergency settings, with an anastomosis leak rate of only 4.5% and no significantly increased risk of death. Proper patient selection for each type of operation is important.
The morbidity rate from surgical complications was high at 41.30%, mainly owing to minor complications such as surgical site infection (SSI) (16.30%). Because the average time to the OR for emergency colorectal surgery was 60 minutes in our study, the time of source control in perforation was not delayed, which represents one factor that facilitated good outcomes. Patients with older ages required postoperative intensive care at a rate of 14.13%. The reasons for an intensive care requirement in our older patients was owing to septic shock and respiratory failure, leading to postoperative ventilator dependency. Morbidity from ventilator dependency in older patients was high (83.33%); in patients who died postoperatively, ventilator dependency had an 0.08-fold increased risk of death (p < 0.05). Postoperative advanced surgical critical care is important for preventing death and promoting early extubation. Preoperative nutrition status was not a significant risk factor of death, as in a previous report.(3) Average intraoperative fluid replacement was 1550 mL, which was also not a risk factor of death; however, this may cause postoperative volume overload in patients with low cardiac functional reserve.