In the setting of hypertrophic pyloric stenosis in order to reach optimal patient care and better prognosis, various induction, maintenance, and postop recovery care have been developed. One of the major concerns among these patients’ anesthesia is to decrease the duration of emergence and recovery steps. Prolongation of these steps may increase the risk of apnea among the patients. On the one hand, prolongation of the recovery phase is related to alkalemia and concomitant increase in cerebrospinal fluid pH, which is believed to be the culprit for the occurrence of apnea. On the other hand, using opioids for analgesia also has been implicated in prolongation of the recovery phase [11–14].
As discussed in section-1, choosing the proper anesthesia method is way more important and rather challenging than surgery technic among the patients with hypertrophic pyloric stenosis. Furthermore, current literature brings more questions in mind than answers regarding the use of proper analgesic methods during anesthesia induction in these patients. However, this clinical trial provides remarkable information responding to some of these questions.
Based on the literature, HPS generally expected to occur in the first offspring of the family and mostly among male infants . In this study, likewise, the literature number of affected males was more than females (M: F = 3:1).
During the recovery, infants should be monitored for apnea, respiratory failure, and drop in body temperature related to metabolic alkalosis . There were no cases of postoperative apnea or alteration in blood gas status found among our studied patients.
Based on a study by Galinkin J.L. et al., premature infants are more commonly prone to experience apnea following pyloroplasty surgery. However, it does not mean term infants are protected against apnea, and it may happen among all children undergoing pyloroplasty surgery regardless of their gestational age . In our study, all patients had controlled respiratory pattern and did not develop apnea.
In the present study, the total anesthesia duration time (T1), the time duration from anesthesia initiation till extubation (T2), and the recovery time (T3) were recorded and compared between two groups. According to obtained data, although the differences in those variables are not significant between two groups, the patients in the acetaminophen group showed clinically significant lower duration in time required for extubation and the time spent in recovery. This clinical discrepancy is not dismissible, and the statistical results may have occurred due to the smallness of the sample size.
In a study by Yung A. et al. comparing the analgesic effects of intravenous versus rectal acetaminophen on 68 patients who underwent a pyloroplasty surgery owing to HPS, the authors revealed that there was no difference in pain control in intravenous and rectal acetaminophen. Hence, they suggested that the use of the rectal form of acetaminophen could be substituted with the conventional IV route among these children .
In this study, patients of the two groups were compared in the context of postoperative pain using the FLACC score, which showed lower pain experience among the patients who were treated with rectal acetaminophen, though the pattern showed a downtrend pain rate in both groups. We believe that this has happened because of the shorter half-life of fentanyl compared to acetaminophen. As demonstrated in figure-2, spending an hour after surgery, the analgesic effect of fentanyl was diminished, and it results in an increase in mean FLACC score among group F patients. Adding this to the other advantages of the acetaminophen compared to fentanyl -which is safe, has fewer side effects, well tolerable without CNS depressant effects- makes rectal acetaminophen a better choice than fentanyl for analgesic purposes among these patients. Moreover, the rectal route of administration of acetaminophen does not have disadvantages of the intravenous route [4, 18–20].
Alongside the strength of the current study toward answering the ambiguity in previous researches, it also has some limitations. The shortness of the study sample size was the most important of them. Moreover, the method of evaluating apnea among the patients was the other limitation of this study. The recent limitation emerged from the shortage of equipment in the center in which the study was conducted.