The results of the present study indicated that the administration of ketamine and dexmedetomidine combination (Ketadex) was associated with a lower blood pressure decrease than the administration of ketamine and propofol combination (Ketofol) during and after the children’s endoscopic procedure. In fact, the blood pressure was higher in the Ketadex group than in the Ketofol group, while the children’s HR was significantly lower in the Ketadex group than in the Ketofol group. The RR and SpO2 factors were not significantly different between the 2 groups over the majority of follow-up times.
Amer et al. conducted a similar study on the effect of adding ketamine to dexmedetomidine and propofol during gastrointestinal endoscopy in children, finding that hemodynamic parameters did not differ significantly between the Ketofol and Ketadex groups (
24). However, the mean SpO
2 was higher in the Ketofol group than in the Ketadex group (
24). The results of another study indicated that the rate of bradycardia was significantly higher in the Ketofol group than in the dexmedetomidine group (
6). Tosun et al. revealed that HR was significantly higher in the Ketadex group than in the Ketofol group (
28). Azizkhani et al. showed that the mean of PR, MAP, and SpO
2 was not significantly different between the Ketadex and Ketofol groups (
10).
Additionally, Joshi et al. reported a similar reduction in HR in the Ketadex group (
29). Although the reduction was more in the Ketadex group than in the Ketofol group, this difference was not statistically significant. The mean SBP and DBP decreased in both groups after induction; however, no statistically significant difference was observed in the mean blood pressure between the 2 groups during the cardiac catheterization procedure (
29). Although in our study, SpO
2 was not significantly different between the 2 groups, the mean blood pressure and PR were higher and lower in the Ketadex group than in the Ketofol group. The observed difference in the results may be attributed to different follow-up times and procedures performed for children.
Morray et al. evaluated the hemodynamic effects of ketamine in children with congenital heart disease and concluded that hemodynamic changes after administration of ketamine in children undergoing cardiac catheterization were minor and did not change the patients’ clinical status or the information obtained from cardiac catheterization (
30).
It is noteworthy that the drug dose can affect the patient’s hemodynamic status and recovery time. Ketamine at a dose of 1 or 2 mg/kg/h, along with dexmedetomidine (1 μg/kg) or propofol (1 mg/kg), was prescribed in the cardiac catheterization procedure (
28-
30), or ketamine at a dose of 1 mg/kg/h, along with dexmedetomidine (0.5 μg/kg) or propofol (100 μg/kg), was prescribed during dressing changes in the pediatric burn patients (
31). In the present study, ketamine at a minimum dose of 0.4 mg/kg for anesthesia induction and 0.4 mg/kg/h for anesthesia maintenance, along with dexmedetomidine (0.7 - 1 μg/kg) or propofol (50 - 100 μg/kg) was prescribed. In fact, the combined dose of drugs was lower in our study than in many other studies.
Some recent reports have shown that the combination of sedatives (such as propofol and ketamine) can be safe and effective (
32). Propofol, with its antiemetic and antianxiety properties, neutralizes the effects of vomiting and emergency reactions of ketamine. Moreover, the sympathomimetic effects of ketamine neutralize the propofol-induced decrease in blood pressure (
33).
Furthermore, dexmedetomidine can effectively and safely reduce not only the hemodynamic blood pressure reaction caused by ketamine but also the psychological effects of ketamine (
19). In fact, dexmedetomidine is expected to prevent tachycardia, high blood pressure, sialorrhea, and the emergence phenomenon associated with ketamine. Ketamine may prevent the bradycardia and hypotension reported with dexmedetomidine (
34).
It should be noted that although ketamine has an excellent safety profile, it is contraindicated in children younger than 3 months of age due to concerns about airway complications. On the other hand, there was no increase in side effects at the age of more than 1 year. Therefore, it can be stated that the combined use of ketamine with dexmedetomidine or propofol results in the attainment of sedation with lower doses of each drug; as a result, it is associated with less toxicity and faster recovery time (
35).
In this regard, the findings of the present study revealed that there was no significant difference in the incidence of adverse effects, the mean procedure time, and the endoscopist’s satisfaction level following the use of both drug combinations. Moreover, there was no significant difference in the sedation induction; however, the recovery time was significantly longer in the Ketadex group than in the Ketofol group.
In line with the findings of the present study, Tosun et al. investigated these 2 drug combinations for sedation of children undergoing cardiac catheterization and showed that the recovery time was longer in the dexmedetomidine-ketamine combination group than in the propofol-ketamine combination group; however, there was no preference for one of them in the induction of sufficient sedation (
28).
In addition, Xu et al. stated that both esketamine-propofol and dexmedetomidine-propofol administration produced the same sedation for pediatric patients undergoing 3 Tesla (T) magnetic resonance imaging (MRI), though esketamine-propofol sedation reduced the need for propofol without increasing side effects (
36). Another study in children undergoing gastrointestinal endoscopic procedures also showed that post-procedure nausea and vomiting were less in the Ketofol group than in the Ketadex group; however, there was no difference in endoscopic satisfaction between the 2 groups (
24).
Vázquez et al. indicated that the recovery time was shorter and patient satisfaction was higher in the dexmedetomidine group than in the control group (
37), which is in line with the findings of the present study, though our study addressed the endoscopist’s satisfaction level. Some other studies have also found that dexmedetomidine has lower respiratory adverse effects and respiratory depression than midazolam and propofol (
38,
39).
Another study also indicated that the recovery time was longer in the Ketadex group than in the Ketofol group. None of the groups had adverse effects, such as bradycardia, decreased oxygen saturation, blood pressure requiring treatment, convulsions, larynx spasms, restlessness, hiccups, chills, increased oral secretions, nausea, and vomiting (
29). Similarly, rare adverse effects (including oxygen desaturation, hypotension, tachycardia, nausea, and vomiting) were reported in our study, and only 2 patients suffered from bradycardia in the Ketadex group.
It should be noted that attention to the age group of children and the use of the minimum doses of the combined sedation drugs in common outpatient diagnostic and treatment procedures in children can be among the strengths of this study. However, the small sample size, the lack of comparison between different drug doses, and the lack of comparison between the effects of each drug alone and drug combinations can be limitations of the present study. Therefore, it is suggested to conduct future studies with special attention to the evaluation of the effects of prescribing each of these drugs alone and in combination with ketamine and other procedures in children.
5.1. Conclusions
The combination of propofol with low-dose ketamine was associated with a shorter recovery time than the combination of dexmedetomidine with low-dose ketamine following children’s upper gastrointestinal tract endoscopy. However, the 2 studied combinations did not differ significantly in terms of the level of sedation, incidence of adverse effects, procedure time, and endoscopist’s satisfaction level.