Dexmedetomidine in paediatric anaesthesia

Fighting ferroptosis: Protective effects of dexmedetomidine on vital organ injuries

Vital organ injury is one of the leading causes of global mortality and socio-economic burdens. Current treatments have limited efficacy, and new strategies are needed. Dexmedetomidine (DEX) is a highly selective α2-adrenergic receptor that protects multiple organs by reducing inflammation and preventing cell death. However, its exact mechanism is not yet fully understood. Understanding the underlying molecular mechanisms of its protective effects is crucial as it could provide a basis for designing highly targeted and more effective drugs. Ferroptosis is the primary mode of cell death during organ injury, and recent studies have shown that DEX can protect vital organs from this process. This review provides a detailed analysis of preclinical in vitro and in vivo studies and gains a better understanding of how DEX protects against vital organ injuries by inhibiting ferroptosis. Our findings suggest that DEX can potentially protect vital organs mainly by regulating iron metabolism and the antioxidant defense system. This is the first review that summarizes all evidence of ferroptosis's role in DEX's protective effects against vital organ injuries. Our work aims to provide new insights into organ therapy with DEX and accelerate its translation from the laboratory to clinical settings.

Prophylactic application of dexmedetomidine reduces the incidence of emergence delirium in children: A systematic review and meta-analysis

BACKGROUND

Emergence delirium (ED) is a common postoperative cognitive dysfunction in children. ED may cause distress to patients and their families in the early post-anesthesia period and have long-term adverse effects on children. THE PRIMARY PURPOSE: was to verify whether dexmedetomidine can reduce the occurrence of ED in children.

RESEARCH TYPE

Systematic review and meta-analysis of RCTs.

DATA ACQUISITION

A search was conducted on Web of Science, WHO Trials, Cochrane Library, Clinical Trials.gov, and PubMed for all published studies from inception to 23 Oct. 2022.

ELIGIBILITY CRITERIA

Randomized clinical trials that met the following criteria: patients aged 1-18 years, study site in the PACU (Post-anesthesia care unit), incidence of ED as the primary outcome, and prophylactic use of dexmedetomidine defined as injected before admission to the PACU.

RESULTS

A total of 7 randomized trials were included (6 studies during eye and neck surgery, 1 during hernia surgery), involving 512 patients (257 (50.1%) with dexmedetomidine, and 250 (49.9%) with control. ED was observed in 17.51% of the patients treated with dexmedetomidine and in 43.14% of those receiving control (risk ratio (RR) = 0.40, 95 % confidence interval [CI] [0.30-0.55], P < 0.00001). Additionally, the prophylactic application of dexmedetomidine also reduced the occurrence of Post-Operating Nausea and Vomiting (RR = 0.24, 95%CI [0.12-0.49], P = 0.0001) and PACU stay time after extubation (mean difference (MD) = -1.57, 95%CI [-3.07 to -0.07], P = 0.04). However, sensitivity analysis of RCTs showed that our effect estimates were not stable (MD = -1.78, 95%CI [-4.18-0.62], P = 0.15).

CONCLUSION

The prophylactic use of dexmedetomidine was associated with a reduction of ED. However, our findings only apply to eye and neck surgery.

TRIAL REGISTRATION

PROSPERO: CRD42022371840.

Comparison of intranasal dexmedetomidine versus oral midazolam for premedication in pediatric patients: an updated meta-analysis with trial-sequential analysis

BACKGROUND

Midazolam is routinely used as preanesthetic medication in pediatric patients. Recently, dexmedetomidine has emerged as an alternative as a premedicant. We aimed to add more evidence about the efficacy and safety of two common routes of administration for pediatric premedication: oral midazolam versus intranasal dexmedetomidine.

METHODS

We systematically searched Randomized Controlled Trials (RCTs) involving patients ≤ 18 years old undergoing preanesthetic medication and comparing intranasal dexmedetomidine with oral midazolam. Risk Ratio (RR) and Mean Difference (MD) with 95% Confidence Intervals (95% CI) were computed using a random effects model. Trial-sequential analyses were performed to assess inconsistency.

RESULTS

Sixteen RCTs (1,239 patients) were included. Mean age was 5.5 years old, and most procedures were elective. There was no difference in satisfactory induction or mask acceptance (RR = 1.15, 95% CI 0.97-1.37; p = 0.11). There was a higher incidence of satisfactory separation from parents in the dexmedetomidine group (RR = 1.40; 95% CI 1.13-1.74; p = 0.002). Dexmedetomidine was also associated with a reduction in the incidence of emergence agitation (RR = 0.35; 95% CI 0.14-0.88; p = 0.02). Heart rate and mean arterial pressure were marginally lower in the dexmedetomidine group but without clinical repercussions.

CONCLUSION

Compared with oral midazolam, intranasal dexmedetomidine demonstrated better separation from parents and lower incidence of emergence agitation in pediatric premedication, without a difference in satisfactory induction. Intranasal dexmedetomidine may be a safe and effective alternative to oral midazolam for premedication in pediatric patients.

Study of caudal ropivacaine with or without dexmedetomidine for postoperative analgesia in paediatric genitourinary infraumbilical surgery: a double-blinded randomized controlled trial

Various studies have described the use of Dexmedetomidine with local anaesthetic drugs in caudal blocks for the management of postoperative pain in children. This study was designed to determine the analgesic effect of caudal Dexmedetomidine with Ropivacaine in paediatric genitourinary infraumbilical surgeries. Postoperative analgesic effects of caudal Ropivacaine with or without Dexmedetomidine in paediatric genitourinary infraumbilical were evaluated. This study was a prospective, interventional, comparative study conducted after ethical approval from the institute. Informed expressed consent was taken from each patient's guardians. The sample size was calculated to be 31 in each group. The two groups were randomly assigned and the intervention involved caudal epidural injection with either Ropivacaine combined with Dexmedetomidine or Ropivacaine with Normal Saline. Children receiving Ropivacaine with Dexmedetomidine had a significantly prolonged duration of analgesia compared to those receiving Ropivacaine alone (840.35 ± 149.97 vs. 412.90 ± 93.46 min, P < 0.001). Postoperative rFLACC scores were consistently lower in the Dexmedetomidine group, indicating better pain control (P < 0.05 at 6, 12, and 24 h). Total analgesic consumption was lower in the Dexmedetomidine group (500.67 ± 212.92 vs. 741.75 ± 268.06 mg, P < 0.01). No significant differences in adverse effects were observed between the groups. The addition of Dexmedetomidine to Ropivacaine in caudal epidural significantly prolongs analgesia, improves pain control, and reduces analgesic consumption in paediatric genitourinary infraumbilical surgeries.

Median effective dose of intranasal dexmedetomidine for satisfactory mask induction in children undergoing examination under anaesthesia for retinoblastoma - A prospective up and down sequential allocation study

Background and Aims

Inhalational technique is used to induce anaesthesia in children without intravenous access. We aimed to determine the median effective dose (ED50) of intranasal dexmedetomidine to ensure satisfactory mask acceptance during inhalation induction in children with retinoblastoma undergoing examination under anaesthesia.

Methods

A prospective sequential allocation study was conducted in children aged 1-60 months divided into Group A (1-18 months) and Group B (18-60 months). Children were administered dexmedetomidine intranasally as premedication. Sedation was assessed using the modified Observer Assessment of Alertness and Sedation Scale until induction. Successful mask acceptance was defined as a cooperative or asleep child during inhalational induction. The starting dose of dexmedetomidine was 1 µg/kg. The next dose varied by 0.2 µg/kg depending on the outcome of this case. According to the Dixon up-and-down method, the mean of midpoints of the failure-success sequence was calculated to obtain the ED50 values.

Results

The ED50 of intranasal dexmedetomidine for satisfactory mask acceptance was 0.7 µg/kg (95% confidence interval [CI]: 0.54-0.86) in Group A (n = 23) and 0.96 µg/kg (95% CI: 0.83-1.08) in Group B (n = 25) (P = 0.020). The mean (standard deviation) duration of anaesthesia was 33.5 (14.9) minutes in group A versus 23.5 (8.48) minutes in Group B (P = 0.007).

Conclusion

ED50 was lower in children younger than 18 months than in older children. There was no difference in the time to discharge from the post-anaesthesia care unit despite the procedure being longer in smaller children.

Effects of intranasal and intramuscular dexmedetomidine in cats receiving total intravenous propofol anesthesia

Background and Aim:

The efficacy of intranasal (IN) dexmedetomidine in cats as a premedication remains elusive. Thus, this study aimed to compare the perioperative and sparing effects of IN and intramuscular (IM) dexmedetomidine administration on propofol requirements for anesthetic induction in cats.

Materials and Methods:

This study randomly assigned 16 cats into two groups of IN or IM dexmedetomidine at 20 μg/kg. Sedation scores and side effects were recorded at time points of 0, 5, 10, 15, and 20 min after the dexmedetomidine administration. Anesthesia was induced with intravenous (IV) 1% propofol by titrating a bolus of 2 mg every 45 s and the total dose of the administered IV propofol to achieve endotracheal intubation was recorded.

Results:

Cats receiving IM dexmedetomidine were significantly associated with higher sedation scores. All cats were sedated at 20 min after premedication; however, the average composite sedation scores in the IN group were significantly lower than those in the IM group during premedication. Pre-operative side effects, including vomiting, were more frequently observed in the IN group (5 cats, 62.5%) than in the IM group (3 cats, 37.5%; p < 0.05). Higher body temperature (>1°F compared to baseline) was more frequently observed in the IN group (6 cats, 75.0%) than in the IM group (1 cat, 12.5%; p < 0.05). The dosage of required propofol in the IN group was significantly higher (1.1 ± 0.3 mg/kg) than that in the IM group (0.7 ± 0.2 mg/kg; p < 0.05). The duration of general anesthesia was comparable between the groups.

Conclusion:

IN dexmedetomidine produces moderate sedation and cats may have side effects, including vomiting and higher body temperature. Higher sparing effects of propofol were identified in the IM group compared with the IN group. Nonetheless, IN administration of dexmedetomidine provides a noninvasive alternative to the IM route.

Best Evidence-Based Dosing Recommendations for Dexmedetomidine for Premedication and Procedural Sedation in Pediatrics: Outcome of a Risk-Benefit Analysis By the Dutch Pediatric Formulary

BACKGROUND

Dexmedetomidine is currently off-label for use in pediatric clinical care worldwide. Nevertheless, it is frequently prescribed to pediatric patients as premedication prior to induction of anesthesia or for procedural sedation. There is ample literature on the pharmacokinetics, efficacy and safety of dexmedetomidine in this vulnerable patient population, but there is a general lack of consensus on dosing. In this project, we aimed to use the standardized workflow of the Dutch Pediatric Formulary to establish best evidence-based pediatric dosing guidelines for dexmedetomidine as premedication and for procedural sedation.

METHOD

The available literature on dexmedetomidine in pediatrics was reviewed in order to address the following three questions: (1) What is the right dose? (2) What is known about efficacy? (3) What is known about safety? Relevant literature was compiled into a risk-benefit analysis document. A team of clinical experts critically appraised the analysis and the proposed dosing recommendations.

RESULTS

Dexmedetomidine is most commonly administered via the intravenous or intranasal route. Clearance is age dependent, warranting higher doses in infants to reach similar exposure as in adults. Dexmedetomidine use results in satisfactory sedation at parent separation, adequate sedation and a favorable recovery profile. The safety profile is good and comparable to adults, with dose-related hemodynamic effects.

CONCLUSION

Following the structured approach of the Dutch Pediatric Formulary, best evidence-based dosing recommendations were proposed for dexmedetomidine, used as premedication prior to induction of anesthesia (intranasal dose) and for procedural sedation (intranasal and intravenous dose) in pediatric patients.

Application of Different Doses of Dexmedetomidine Combined with General Anesthesia in Anesthesia of Patients with Traumatic Tibiofibular Fractures and Its Effect on the Incidence of Adverse Reactions

Objective

To explore the application of different doses of dexmedetomidine combined with general anesthesia in patients with traumatic tibiofibular fractures.

Methods

A total of 120 patients with traumatic tibiofibular fractures treated in our hospital (January 2018–January 2021) were selected as the research subjects and equally grouped into group A, group B, group C, and group D according to the dosage of dexmedetomidine. Group B, group C, and group D were pumped with 0.3 μg/kg, 0.5 μg/kg, and 0.8 μg/kg load doses of dexmedetomidine before anesthesia induction, with the same doses for maintenance during surgery. Group A was intravenously pumped with the same amount of normal saline and received tracheal intubation after anesthesia induction, with propofol and remifentanil to maintain general anesthesia during surgery.

Results

No notable differences in general data were observed among the groups (P > 0.05). Ramsay sedation scores of all groups showed a downward trend after drug withdrawal. At 10 min, 30 min, and 60 min, the scores of groups C and D were markedly higher than those of groups A and B (P < 0.05), and the scores were higher in group D than those in group C (P < 0.05). The HR changes at each period were close between groups A and B (P > 0.05). The HRs at T1 and T2 in group C were slightly lower than those in group D (P > 0.05), and the HRs at T1 in groups A and B were remarkably higher than those in groups C and D, and were higher than those at T0 and T2 (P < 0.05). The SBP levels of all groups began to rise at T0, peaked at T1, and decreased to a lower level at T2 than that at T0. Moreover, the SBP levels of groups C and D at T1 and T2 were notably lower compared with groups A and B (P < 0.05). With a lower DBP level in group C than the other three groups at T1, the DBP levels were notably lower in groups C and D than those in groups A and B at T2 (P < 0.05). With no statistical difference in the MAP levels at T0 among the four groups (P > 0.05), the MAP levels in group A at T1 and T2 were obviously higher compared with groups C and D (P < 0.05). The extubation time in group A was notably longer than that that in groups B, C, and D (P < 0.05), with longer extubation time in group B than that in groups C and D (P < 0.05). The orientation recovery time in group D was markedly shorter than that in groups A, B, and C (P < 0.05). The incidence of cognitive dysfunction, chills, and restlessness in groups C and D was notably lower compared with groups A and B (P < 0.05), with a higher incidence of chills, intraoperative hypotension, and delayed awakening in group D than in group C (P < 0.05).

Conclusion

Dexmedetomidine at doses of 0.5 μg/kg and 0.8 μg/kg has a better effect in the maintenance of general anesthesia for patients with traumatic tibiofibular fractures, with faster orientation recovery, better recovery of postoperative cognitive function, and a lower incidence of adverse reactions. Dexmedetomidine at 0.5 μg/kg is recommended in view of the increased risk of excessive sedation, chills, restlessness, and intraoperative hypotension in patients at 0.8 μg/kg.

The effect of intraoperative dexmedetomidine administration on length of stay in the post-anesthesia care unit in ambulatory surgery: A hospital registry study

STUDY OBJECTIVE

Dexmedetomidine, which is commonly used for procedural sedation and as adjunct to general anesthesia for ambulatory procedures, may affect patient discharge from the post-anesthesia care unit (PACU). We hypothesized that intraoperative dexmedetomidine use in ambulatory surgery is associated with delayed discharge from the PACU and that this is modified by surgical duration and anesthesia type.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENTS

130,854 adult patients undergoing ambulatory surgery between 2008 and 2018.

INTERVENTIONS

Intraoperative administration of dexmedetomidine.

MEASUREMENTS

The primary outcome was PACU length of stay. In secondary and exploratory analyses, we examined dose-dependency, effect modification by duration of surgery and anesthesia type, effects of timing of dexmedetomidine administration, and PACU discharge delays.

MAIN RESULTS

Dexmedetomidine was associated with a prolonged PACU length of stay (adjusted absolute difference [AD_adj] 15.0 min; 95%CI 12.7-17.3; p < 0.001). This effect was dose-dependent (p-for-trend < 0.001), magnified in surgeries of less than one hour (AD_adj 20.7 min; 95%CI 16.7-24.7; p < 0.001) and in patients undergoing monitored anesthesia care compared to general anesthesia (AD_adj 16.8 min; 95%CI 14.1-19.6; p < 0.001). The effect was more pronounced if dexmedetomidine was administered within the last 60 min of surgery (AD_adj 18.7 min; 95%CI 15.7-21.7; p < 0.001). Dexmedetomidine was associated with discharge delays due to cardiovascular complications (OR_adj 2.27; 95%CI 1.59-3.24; p < 0.001) and over-sedation (OR_adj 1.28; 95%CI 1.11-1.48; p < 0.001). In patients who received dexmedetomidine (n = 2901), the use of bolus doses only versus the combination of bolus and infusions, magnified the effects on PACU length of stay (AD_adj 29.5 min per μg/kg; 95%CI 17.3-41.8 versus 18.1 min per μg/kg; 95%CI 11.4-24.8; p < 0.001).

CONCLUSIONS

The intraoperative administration of dexmedetomidine was dose-dependently associated with a prolonged PACU length of stay. Clinicians should judiciously titrate dexmedetomidine, especially when using this long-acting drug for monitored anesthesia care for shorter procedures.

Dexmedetomidine and Tear Production: Evaluation in Dogs as Spontaneous Model for Ocular Surface Disorders

Simple Summary

The general anesthesia or sedation reduces both the tear production and the stability of tear film that protect corneal surface, predisposing itself to the exposure keratopathy. The aim of the present study was to evaluate the effects of intramuscular dexmedetomidine (DEX) on canine tear production, measured by standardized Schirmer Tear Test 1 (STT-1) strips, for the 8 h following sedation, in dogs. A significant effect of time on canine tear production was found, highlighting that dexmedetomidine sedative protocol significantly affects tear production in dogs. It is recommended to treat the canine eyes with tear substitutes to protect ocular surface health and the welfare of the dogs. The ocular lubrication should be performed during and up to 12 h after sedation. The present report could provide preliminary information to better understand the effect of DEX on the tear film dynamics.

Abstract

Tear film provides lubrication and protection to the ocular surface. The sedation reduces tear production, often leading to perioperative exposure keratopathy. The aim of the present study was to report the effects of intramuscular dexmedetomidine on canine tear production, measured by STT-1, for an experimental period of 8 h after sedation. Ten dogs who underwent sedation for routine radiologic assessment were recruited for the study. In all animals, tear production in right and left eyes was measured 15 min before sedation (T0: basal values) and 20 min (T20), 1 h (T1), 2 h (T2), 4 h (T4) and 8 h (T8) after drug administration. Analysis of variance and post hoc Bonferroni test (p < 0.05) were performed. A significant effect of time on canine tear production was found. The tear production returned to basal values at T8. So, it is recommended to treat the canine eyes with tear substitutes during and up to 12 h after sedation.

Management of the Unexpected Difficult Airway in Neonatal Resuscitation

A "difficult airway situation" arises whenever face mask ventilation, laryngoscopy, endotracheal intubation, or use of supraglottic device fail to secure ventilation. As bradycardia and cardiac arrest in the neonate are usually of respiratory origin, neonatal airway management remains a critical factor. Despite this, a well-defined in-house approach to the neonatal difficult airway is often lacking. While a recent guideline from the British Pediatric Society exists, and the Scottish NHS and Advanced Resuscitation of the Newborn Infant (ARNI) airway management algorithm was recently revised, there is no Norwegian national guideline for managing the unanticipated difficult airway in the delivery room (DR) and neonatal intensive care unit (NICU). Experience from anesthesiology is that a "difficult airway algorithm," advance planning and routine practicing, prepares the resuscitation team to respond adequately to the technical and non-technical stress of a difficult airway situation. We learned from observing current approaches to advanced airway management in DR resuscitations in a university hospital and make recommendations on how the neonatal difficult airway may be managed through technical and non-technical approaches. Our recommendations mainly pertain to DR resuscitations but may be transferred to the NICU environment.