This study was the first in Iran to assess the perioperative mortality of children. Perioperative mortality is a vital tool for assessing the quality of care, safety of surgery and anesthesia provided to patients, especially in low-income and poor countries where access of patients to qualified surgical and anesthetic services is limited (7).
In the current study, 30-day perioperative mortality rate in a specialized pediatric hospital was 27.44 per 10000 procedures. In a study performed in Netherlands (6) on patients younger than 18 years old, hospital mortality within 30-day post-surgery was 41.6 per 10000 procedures. According to a study in Melbourne, Australia (10), 30-day hospital mortality was 34.5 per 10000 procedures. Differences in mortality rates between different studies could be due to the variations in design and population of various studies (11).
Analysis of results showed that age of patients had a significant relationship with time interval between surgery and death, so that most number of deaths especially in infants and children lower than 3 years old, were happened within 30-day post-surgery. The study performed by Pignaton et al. (12), showed that children younger than 1-year-old were the major risk of perioperative mortality. In a five-year study to investigate the incidence and factors of perioperative cardiac arrest and mortality in a pediatric surgical population, the age of less than 1 year was identified as the main risk factor (13). According to the results, sex of patients was not a major predictor for perioperative mortality. In a multicenter, cohort study in low-income countries to measure 30-day postoperative mortality in children aged < 16 years, sex of patients was not determined as a predictor of mortality (14). In contrast to the present study, a significant relationship between female sex and perioperative mortality was found in a study conducted in Ghana (15). In a study in California (16), individuals < 21 years old who had cardiac surgery were selected to evaluate the role of gender in cardiovascular outcomes. Results showed that female sex was a risk factor for mortality among children who underwent cardiac surgery. This result became more interesting when it was clear that the proportion of neonates in females was less than males, and procedures that were used for females had lower risk compared with males.
In the present study, the mortality rate decreased significantly with age; so that the mortality rate in children over 10 years of age was 4.7-fold lower than in children less than 1 year of age. In a study of children under the age of 15 in Nigeria, the risk of death in children under the age of 1 was nine times higher than in older children (7). Rising risk in this age group can be related to congenital anomalies and sepsis (17). This may also be due to the immature status of immune systems in neonates and infants (18).
The present study did not show a significant relationship between postoperative mortality and emergency surgical status, which contradicts the results of studies conducted in developing low-income countries. Bharti et al. (13), and Bunchungmongkol et al. (19), expressed that patients whom surgery was at emergent status had more risk of perioperative mortality compared with cases of elective surgery.
In present research, type of surgery was determined as an indicator of perioperative mortality. In a study done at a Brazilian tertiary hospital (12) to evaluate the perioperative and anesthesia-related mortality rates, surgery-related factors were determined as one of two major causes of mortality. Moreover, in the Brazilian study (12), complications associated with cardiac surgery were among the most frequent causes of deaths. Cardiac disease was the most frequent associate disease among the cases of mortality according to the results of present research. According to Flick et al. (20), and Van der Griend et al. (10), cardiac surgery leads to higher rates of perioperative mortality compared with non-cardiac surgery.