INTRODUCTION

Emergence delirium (ED) is the alteration of the child's consciousness and attention to his environment with disorientation and perceptual alterations in the period immediately after anesthesia¹. The factors associated with ED in children are not precisely known, especially in developing countries like Peru. The incidence in postoperative children, according to world literature, ranges between 2% and 80%².

In Latin America and the Caribbean, the ED is reported between 13% and 56%^3-7. n Cuba and Jamaica, it is between 13% and 56%; in Chile, Colombia and Ecuador it is between 13% and 39%.

It is estimated that the average occurrence of ED in postoperative children after the use of sevoflurane could be 30%, taking into account that some pathologies require multiple procedures in the operating room such as placement of venous access in difficult venous routes⁸.

An agitated awakening can occur unexpectedly, causing the child to remove these accesses or hit the stretcher railings, generating discomfort when the father is present and stress in the staff in charge since they must focus their efforts on caring for more time the minor or requiring the use of more medications to control it, prolonging his recovery⁸.

There are several associated factors; nevertheless, in Peru, there are no published studies on the incidence of ED in the pediatric population. The results suggest that pain is the only factor associated with ED. Prevention and treatment should focus on postoperative pain control and careful monitoring of patients after surgery. Furthermore, this research was one of the first to include patients who required palliative care^3,9-11.

During the first half of 2021, the INSNSB (Instituto Nacional de Salud del Niño San Borja-by its name in Spanish) performed nearly 2,600 surgeries, which is a significant number in children, considering that local and global anesthesia societies are currently directing their efforts towards patient safety in anesthesia through the campaign for safe surgery.

The INSNSB is a national reference center at the third level of care in Peru. It is the only institution with a Pediatric Pain Therapy and Palliative Care Unit at the local level. The literature describes that children in palliative care require multiple interventions under anesthesia¹².

Worldwide, it is estimated that, according to differences in populations and types of studies, nearly 22 million children need palliative care^13,14,15.

The objective of this study was to determine the factors associated with ED in children from the Post-Anesthetic Recovery Unit (PARU) of the Instituto Nacional de Salud del Niño San Borja (INSNSB). This can help identify patients at higher risk and take measures to prevent its appearance or treat it in a timely manner, thus limiting the undesirable consequences of their care, such as generating dissatisfaction among health personnel and parents.

METHODS

RESULTS

150 children participated in the study. The majority (61.3%) were under 5 years of age and had an ASA-PS II classification (98%), there was a homogeneous distribution between both sexes (50.7% men and 49.3% women), for 75 kids the procedure lasted a median time of 62 minutes (IQR = 35 - 140 minutes) and 14% (21) presented pain. The number of procedures was similar between those who underwent surgery and those who did not. Finally, during data collection, it was noted that about half (46.7%) had diagnoses requiring palliative care (see Table 1).

ED occurred in 10.6% (16) of the children. Of them, the majority (81.4%) were under 5 years old, male (68.8%), ASA-PS II (87.5%), and underwent a surgical procedure (56.3%). , needed palliative care (68.8%) and 37.5% presented pain. The median duration of any procedure was 56 minutes (IQR = 37 - 147.5 minutes) (see Table 1).

Regarding the anesthetic characteristics, the majority registered midazolam as premedication (69.4%), the distribution of the type of anesthesia was similar between the use of inhalation and intravenous agent (48.7% and 46.8%, respectively), followed by the use of regional anesthesia (peripheral and caudal nerve block) in 4.5%. The most commonly used intraoperative analgesic strategy was metamizole (47%), followed by tramadol and morphine (31.2% and 14.6%, respectively). Regarding the anesthetic agent used, the main drugs used were sevoflurane, fentanyl and propofol (32.3%, 24.4% and 25.2%, respectively). On the other hand, 38.6% recorded permanence of health personnel and 36.4% recorded use of additional pharmacological therapy as a consequence of the ED (see Table 2).

When the bivariate analysis was performed according to the type of anesthesia, ED was observed mostly with inhalation and intravenous anesthesia (53.6% and 39.3%, respectively). A similar situation occurred when metamizole and tramadol were recorded as analgesia (60% and 25%, respectively), as well as in those who received sevoflurane, fentanyl, and propofol (35.7%, 26.2% and 21.4%, respectively). Regarding the consequences of the ED, 41.2% recorded permanence of health personnel, while there were no differences between those who registered additional pharmacological treatment and those who registered self-withdrawal from monitoring (29.4% and 26.5%, respectively). Only one child who lost venous access presented ED (see Table 2).

Likewise, it was found that the presence of pain is associated with ED, with an estimate of PR = 3.69 (95% CI: 1.25 - 9.92) in the crude model. The adjusted model's estimated effect was PR = 3.63 (95% CI: 1.20 - 10.1), controlling for other covariates. All other covariates were not statistically significant (p>0.05) in the crude and adjusted models (see Table 3).

Furthermore, the bivariate analysis shows that the estimate of the raw effect of pain on the presence of ED was PR = 3.69 (95% CI: 1.25 - 9.92), while in the adjusted model pain continues to be an associated factor (PR = 3.5, 95% CI: 1.15 - 9.77), controlling for other covariates of interest. However, no significant evidence of association (p>0.05) was found in the study sample for the covariate type of analgesia (see Table 4).

Finally, the diagnoses of the children requiring palliative care were grouped (70) and it was observed that four presented ED and seven had pain. Thus, the majority of disorders were hematological in 57% (leukemia, lymphoma, aplastic anemia). Of the four children who presented with ED and required palliative care, half belonged to the group of hematological disorders; while, those who had pain were most from spinal disorders (scoliosis) followed by burns (see Table 5).

DISCUSSION

This study is one of the first local investigations to report results on factors associated with ED in a pediatric institution in Peru and included patients with diagnoses requiring palliative care.

It is highlighted that acute postoperative pain was statistically significant in association with the presence of ED in children admitted to the PARU. This result is similar to a study carried out in Brazil, where acute postoperative pain was found as a factor associated with ED in the multivariate analysis (PR = 3.91; 95% CI: 2.15 - 7.11; p < 0.001 )².

In this regard, the aforementioned study conducted a survey in REDCap® where more than 70% responded that high levels of anxiety and untreated pain constituted risk factors²³.

The incidence of postanesthetic ED was 10.6%. This finding is within the wide range reported by the international literature of 2% to 80% and the most commonly proposed consensus range of 10% to 30%^3,5-7,24,25. Also, it indicates a lower incidence of ED compared to other reports from Latin America and the Caribbean, where an incidence of 13% to 56% is reported. This difference between the various studies may be due to the different demographic characteristics and the multiple methodologies used.

Among children diagnosed with ED, more than half did not experience pain. This confirms that it can be present in non-painful procedures^26,27, although several studies have reported that pain can occur in 45% of children with ED, after otorhinolaryngological procedures^18,28,29.

The reason for this association between pain and the pathophysiology of ED is still unknown; However, some authors suggest that changes in brain conduction between the thalamocortical and limbic systems make the brain vulnerable, depress higher-order attentional and executive networks, which implies dysfunctions in postoperative neurological brain activity².

It has been suggested that ether derivatives (sevoflurane, desflurane) have an almost 4-fold higher occurrence of ED compared to intravenous agents³.

It is believed that low blood/gas solubility inhalation agents produce excitation of the locus ceruleus⁸. Immaturity of the central nervous system and “early awakening” can also contribute⁴.

The immaturity of the cholinergic (parasympathetic) centers of the hippocampus and the alteration of neurotransmitters (increase in dopamine or norepinephrine and decrease in acetylcholine) may provide an explanation for the susceptibility of younger children³⁰.

Some authors postulate that this association found in the study could also be explained by the similarity of the items used in the PAED and FLACC scales²⁸.

Its main strength lies in the use of validated scales, PAED and FLACC, to measure the variables of interest (SD and pain, respectively). There is consensus that the use of the PAED scale improves research methodology in this area, particularly when postoperative pain is controlled¹⁹. Furthermore, it was observed that the use of both scales generated a favorable expectation among the PACU health personnel who were present during data collection, since it allowed early recognition of ED and pain. Although the INSNSB PARU “Postanesthesia Monitoring Sheet” currently uses the modified Aldrete scale for patient discharge, the institutional standard does not currently require the application of these two scales. Therefore, it could be suggested that both scales be routinely used in post-anesthesia evaluation in different hospitals. This could facilitate further research and better planning of post-anesthesia awakening management and pain control.

It is important to note that although postoperative pain was the only factor associated with ED in this study, there are other factors that should be considered during medical evaluation. Future studies should continue to explore whether diagnoses requiring palliative care, age, type of procedure, and especially the use of specific anesthetic agents are associated with ED.

The study has the limitations that it was conducted at a single institution and had a cross-sectional design. Although these studies can be efficient in disease prevalence, short and inexpensive, they can lead to selection biases and make it difficult to verify the causal relationship.

Besides, the sample size may be small to evaluate the association with other factors. In this sense, it is important to carry out multicenter studies.

It is possible that due to the sample size in the covariate subgroups and the imbalance in the distribution of the response variable, the association with these other factors was not evident.

Despite this, its main strength is that it sets an important precedent for future studies in pediatric anesthesia and pediatric palliative care in Peru, and comparative studies at an international level.

In conclusion, a significant association between ED and acute postoperative pain was observed in our study. Therefore, it is suggested that ED treatment should focus on postoperative pain control as well as careful follow-up of patients after surgery to detect this entity and treat it in a timely manner. Age, type of procedure, and anesthetic agent were not statistically significant.