In our single-center observational cohort study, we found that neonates receiving an opiate, vagolytic, and paralytic premedication before intubation were less likely to suffer an adverse TI associated event and had greater first attempt success compared with those receiving either a partial combination of premedication or no premedication. This improvement in TIAEs and first attempt success is especially relevant as neonatal TI remains a challenging technical skill, particularly for less experienced learners. In addition, the use of a full premedication may create a more controlled environment for intubation ensuring patient comfort while minimizing bradycardia and desaturation (3, 4, 6).
Despite recommendations in the neonatal intubation literature, much variability persists regarding premedication usage in the NICU. For example, Sarkar et al. surveyed NICU fellowship program directors and found that 44% of 78 programs responding used sedation for non-emergent TI while only 18% routinely used paralysis; 9 respondents co-administered atropine with opiate analgesia or sedative (e.g., benzodiazepine) and a paralytic (17). Similarly, Carbajal and colleagues reviewed eight studies, including four randomized trials, evaluating different premedication regimens for elective neonatal intubation, concluding that some combination of premedication should be used for all elective intubations, with the most studied regimen being the combination of fentanyl, atropine and a paralytic (5). The addition of atropine in this analysis adds a clinically relevant perspective surrounding the role of atropine in relation to clinically important adverse outcomes such as hypoxemia and bradycardia during tracheal intubation.
Our primary outcome was the incidence of adverse TIAEs between premedication groups. We found the group of infants intubated with full premedication to have significantly fewer adverse TI associated events even in the adjusted model compared to those who received both partial and no premedication. We did not find a difference in the incidence of adverse TIAEs comparing the partial premedication group with the no premedication group. This is in comparison to results in Ozawa et al. where they found a higher occurrence of adverse TIAEs for intubations in the sedation only group compared with no medication (4). Interestingly, similar to their study, we also identified higher odds of severe oxygen desaturation in the partial premedication groups compared to no premedication. These findings may be clinically relevant, particularly when premedication is considered for patients undergoing intubation for surfactant therapy with planned immediate extubation (INSURE) (21).
Patients intubated for INSURE remain at risk for adverse events associated with laryngoscopy and endotracheal tube placement. However, they are not good candidates for premedication with a paralytic as they must maintain spontaneous breathing immediately following extubation. While our study results showed no difference in TIAEs between the partial and no premedication groups there was significantly more hypoxemia during intubation with partial premedication. These results add to the literature evaluating the use of partial premedication for intubation. While we support use of premedication for INSURE to maintain patient comfort during awake intubation, we advise providers to use caution from the standpoint of adverse intubation events. (22, 23).
Our secondary outcomes included the change in heart rate during intubation and first attempt success between premedication groups. We found the partial and full premedication groups to have significantly less heart rate change during intubation than no premedication. This finding is in line with previous studies of intubation safety and adverse events (2, 6, 18, 24). Bradycardia during intubation may be due to vagal stimulation from laryngoscopy and endotracheal tube placement, as well as from hypoxemia (24); atropine mitigates this vagally induced bradycardia. Since atropine was used in nearly all intubations in the full premedication group and 83% of the partial premedication group, it was not surprising that we saw no difference in mild or severe bradycardia between full and partial premedication groups.
Even transient episodes of bradycardia may be clinically significant in that fluctuations in perfusion may be associated with changes in cerebral perfusion pressure and contribute to the development or worsening of intraventricular hemorrhage (6, 8, 10). Use of full premedication, including a paralytic, can potentially mitigate these changes in cerebral hemodynamics occurring during intubation, such as fluctuations in the partial pressure of carbon dioxide (pCO2), bradycardia, and hypoxemia (10, 13). In our dataset, all infants with greater than 40% decrease from their highest recorded heart rate had a low heart rate during TI encounter of less than 100 bpm. Compared with partial and no premedication groups, we found significantly fewer infants in the full premedication group with this substantial decrease in heart rate (> 40% from highest recorded) during intubation. We did not investigate the timing nor incidence of intraventricular hemorrhage for infants in this cohort; however, these two clinically important outcomes should be rigorously explored in the context of transient yet large changes in vital signs during intubation particularly in very low birthweight infants.
We found higher first attempt success for neonates intubated with full premedication compared with partial premedication. Most infants in the partial premedication group received an opiate without paralytic, a scenario that may increase the likelihood of physiologic instability during laryngoscopy without the benefit of the paralytic to optimize the position and view of the glottic structures (4). Although there was a trend towards higher first attempt success between the full and no premedication groups, this was not statistically significant in this retrospective sample.
This study is limited by its data collection at a single center, retrospective approach, and relatively small number of participants. The intubating team collected data, and items such as the highest and lowest heart rate may have been recorded with variable accuracy. Using data from continuous electronic cardiorespiratory monitoring systems may reduce this potential for inconsistency in the future. Only the first TI course data were analyzed in this study which increases the risk of missing TIAEs occurring in subsequent TI courses within the same encounter. Future studies should employ techniques such as propensity score matching to reduce bias due to confounding, specifically in an observational cohort study with unbalanced treatment groups. Furthermore, as units move to utilize new tools and medication to improve the safety of neonatal intubation, it will be important to explore the role of practice changes to minimize variability in sampling.
We conclude that intubations with full premedication, including a vagolytic, opiate analgesic, and paralytic, are associated with fewer adverse TI events and increased first attempt success compared to intubations with a partial combination of premedication; even when adjusting for confounding variables. Compared to intubations without premedication, we found less change in heart rate during intubation with full premedication, a finding attributed to the addition of atropine to this analysis. The use of a regimen including vagolytic, analgesic, and paralytic should be considered as unit guidelines for neonatal intubation are developed.