Comparison of Intravenous Versus Nebulized Dexmedetomidine for Laryngoscopy and Intubation-Induced Sympathoadrenal Stress Response Attenuation

Comparative evaluation of nebulized versus intravenous dexmedetomidine on intubating conditions during awake fiberoptic nasotracheal intubation

BACKGROUND

There is a search for an ideal agent to facilitate awake fiberoptic intubation (AFOI). Dexmedetomidine is a selective α2 agonist which can be administered through intravenous, intramuscular, buccal, intranasal & inhalational routes. It provides good intubation conditions without oxygen desaturation but may cause hypotension and bradycardia when administered intravenously. Hence, alternative routes of administering dexmedetomidine which may improve its safety profile are worth exploring.

METHODS

In this randomised, controlled, double-blind trial, 46 ASA I/II adult participants scheduled for elective ENT surgery were randomly allocated to Group ND (Nebulised Dexmedetomidine) (n = 23) to receive nebulisation with dexmedetomidine 1μg.kg-1 and Group ID (Intravenous Dexmedetomidine) (n = 23) to receive intravenous dexmedetomidine 1μg.kg-1 before AFOI. All the patients received injection midazolam 1 mg i.v. as premedication before anaesthesia was initiated. The primary outcome was the cough score. The secondary outcomes were the RSS, SAYGO boluses, post-intubation score, hemodynamic parameters, recall of the procedure, patient satisfaction score and any side effects.

RESULTS

The cough score was significantly lower in nebulized group (2.43 ± 0.992 vs 3.52 ± 1.082) with p = 0.001. RSS(3.30 ± 0.926 vs 4.22 ± 1.126; p = 0.004), number of SAYGO boluses required (2.74 ± 0.864 vs 3.57 ± 1.161; p = 0.009) & the post intubation score (1.48 ± 0.593 vs 2.17 ± 0.778; p = 0.001) were also significantly lower in nebulized group.

CONCLUSIONS

Nebulisation with dexmedetomidine results in desirable degree of sedation and better tolerance of the procedure with adequate attenuation of the haemodynamic responses to intubation.

Nebulized Versus Intravenously Administered Dexmedetomidine for Obtunding Hemodynamic Responses to Laryngoscopy and Tracheal Intubation: A Randomized Double-Blind Comparative Study

Introduction Intravenous dexmedetomidine is known to cause major adverse effects such as bradycardia, hypotension, cardiac arrhythmias, and heart block when used as premedication for attenuation of the laryngoscopy and intubation response, limiting its routine use. Thus, it is important to study other routes of administration of dexmedetomidine. Objectives To compare the hemodynamic response and sedation score between intravenous and nebulized dexmedetomidine as premedication for the attenuation of the laryngoscopy and intubation response. Materials and methods In this study, 60 patients fulfilling inclusion criteria undergoing surgeries under general anesthesia (ASA Grade I and II) were randomly allocated into two groups of 30 patients each. Group IV received intravenous 1 mcg/kg dexmedetomidine in 100 mL normal saline, and Group IN received nebulization with 1 mcg/kg dexmedetomidine diluted to a total volume of 5 cc of normal saline, 30 minutes prior to the induction of general anesthesia. Sedation scores were calculated using the Ramsay sedation score at 20 minutes after the administration of the drug; patients were induced by the standard protocol, and laryngoscopy was performed. Vitals were recorded before the administration of the drug and after intubation at stipulated time intervals. Results The median heart rate becomes significantly lower at 15 minutes (70 vs. 76.5) and 20 minutes (66 vs. 76) after induction among Group IV as compared to Group IN. The median systolic blood pressure was significantly lower at 20 minutes in Group IV (110 mmHg) than in Group IN (119 mmHg). The median diastolic blood pressure was significantly lower at 10 minutes (76 vs. 79), 15 minutes (70 vs. 77), and 20 minutes (69 vs. 78.5) in Group IV than in Group IN. The median of mean arterial pressure was significantly lower at 15 minutes (84.8 vs. 91.5) and 20 minutes (83 vs. 92) in Group IV than in Group IN. A comparison of vitals after induction shows that the median heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure were significantly lower statistically among Group IV as compared to Group IN at 0, 1, 3, 5, 10, 15, and 30 minutes after induction (except for systolic blood pressure at 3 minutes). The median sedation score was lower in Group IN (0) than in Group IV (1); this difference is statistically significant. Conclusion The obtundation of hemodynamic responses following laryngoscopy and maintaining hemodynamics intraoperatively is statistically better with nebulized dexmedetomidine compared to intravenous dexmedetomidine.

Nebulized dexmedetomidine for attenuating hemodynamic response to laryngoscopy and endotracheal intubation in adult patients undergoing surgeries under general anaesthesia: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Sympathetic stimulation associated with laryngoscopy and endotracheal intubation (ETI) may lead to adverse cardio-/cerebro-vascular events in susceptible patients. Nebulization is a novel route for dexmedetomidine administration providing a large surface area for absorption while avoiding bradycardia and hypotension associated with intravenous route. We aimed to evaluate the efficacy and safety of dexmedetomidine nebulization for attenuating hemodynamic response to ETI in adult patients undergoing surgery under general anaesthesia.

METHODS

This systematic review was registered prospectively in the International Prospective Register of Systematic Reviews (CRD42023403624). PubMed, Embase (OvidSP), Cochrane library, Scopus (Elsevier), Web of Science (Clarivate) and Google Scholar were systematically searched from database inception until March 31, 2023. Two reviewers independently screened titles, abstracts and then full text against pre-specified eligibility criteria. Randomized controlled trials (RCTs) assessing effect of dexmedetomidine nebulization on hemodynamic response to ETI in adult patients undergoing surgeries under general anaesthesia were included. All studies reporting heart rate and systolic blood pressure at baseline and various time points after ETI were included. A pre-piloted data extraction form, Cochrane revised risk-of-bias tool (ROB 2) tool, GRADE approach and RevMan 5.4.1 (Cochrane Collaboration, Copenhagen, Denmark) were used for data extraction, risk of bias assessment, rating certainty of evidence and data synthesis respectively. Mean difference and relative risk with 95% Confidence Interval (CI) were used for continuous and dichotomous variables respectively.

RESULTS

Six RCTs randomized 480 patients with ASA I/II patients aged < 60 years of age and undergoing elective surgeries to receive either dexmedetomidine (n = 240) or saline nebulization (n = 240). Except for one RCT which used 2 μg/kg, all other RCTs used dexmedetomidine dose of 1 μg /kg. Heart rate, systolic, diastolic and mean blood pressure were significantly lower in the dexmedetomidine group at all the measured time points after laryngoscopy and ETI with the only exception being systolic blood pressure at 3 min [mean difference -13.86 (95% CI -30.01 to 2.99), p = 0.09]. Bradycardia and hypotension as adverse effects were absent across the included studies. However, only one-third of the included studies had a low risk of bias and strength of evidence was very low according to the GRADE assessment.

CONCLUSIONS

Compared to placebo, premedication with dexmedetomidine nebulization was associated with lower HR and BP following ETI without any risk of bradycardia and hypotension. However, the strength of evidence was very poor and came from just one country. Future well designed and conducted studies in different populations are warranted.

TRIAL REGISTRATION

PROSPERO Registration number: CRD42023403624.

A Randomized Comparison of Intravenous Versus Nebulized Routes for Administering Dexmedetomidine and Ketamine Combination to Facilitate Awake Fibreoptic Intubation

Introduction Awake fibreoptic intubation is a technique used to secure the airway of patients who are having predicted difficult intubation. We compared two routes, intravenous and nebulized, for administering a combination of ketamine and dexmedetomidine to patients requiring sedation for fibreoptic intubation. Methods and materials After approval of the institutional ethics committee, 64 patients between 18 and 60 years belonging to the American Society of Anesthesiologists physical status I or II and having predicted difficult airway were randomized to receive study medications through either intravenous (group I, n = 32) or nebulized (group N, n = 32) routes. Group I patients were given a combination of ketamine and dexmedetomidine through intravenous route. Group N patients were nebulized with a combination of ketamine and dexmedetomidine. The time required for awake fiberoptic intubation was the primary outcome variable. In addition, sedation score, cough severity, patient tolerance, intubating condition, hemodynamic changes, recall of events and discomfort during intubation, and any adverse events in the perioperative period were also compared. Results Compared to group N, the time needed to intubate the patients was significantly less in group I (75.69 ± 10.83 versus 49.19 ± 3.60 seconds, p < 0.001). Observer assessment sedation/alertness score (p < 0.001), cough severity (p < 0.001), patient tolerance (p < 0.001), and intubating condition (p = 0.001) were statistically significant, all conditions being better in group I. Patient discomfort and recall of the procedure were statistically similar between the groups. Conclusions The efficacy of a combination of dexmedetomidine and ketamine through the intravenous route is better than the nebulized route for patients undergoing awake fibreoptic intubation.