A comparison of dexmedetomidine plus ketamine combination with dexmedetomidine alone for awake fiberoptic nasotracheal intubation: A randomized controlled study

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.

Safety and Efficacy of Dexmedetomidine for Bronchoscopy: A Systematic Review and Meta-Analysis

(1) Background: Anesthetic sedatives are widely used for bronchoscopy, and controversy surrounds the safety and efficacy of dexmedetomidine compared to other sedatives. The aim of this study is to evaluate the safety and efficacy of dexmedetomidine in bronchoscopy through a systematic review. (2) Methods: PubMed, Embase, Google Scholar, and Cochrane Library electronic databases were searched for a randomized controlled study of dexmedetomidine (Group D) or other sedative drugs (Group C) for bronchoscopy. Data extraction, quality assessment, and risk of bias analysis were performed in accordance with the preferred reporting items for systematic review and meta-analysis requirements. Meta-analysis was performed using RevMan 5.2. (3) Results: Nine studies were included, with a total of 765 cases. Compared to Group C, the incidence of hypoxemia (OR = 0.40, 95% CI (0.25, 0.64) p = 0.0001, I² = 8%) and tachycardia (OR = 0.44, 95% CI (0.26,0.74), p = 0.002, I² = 14%) were lower, but bradycardia (OR = 3.71, 95% CI (1.84, 7.47), p = 0.0002, I² = 0%) was higher in Group D; no significant difference was observed in other outcome indicators. (4) Conclusions: Dexmedetomidine reduces the incidence of hypoxemia and tachycardia during bronchoscopy but is more likely to provoke bradycardia.

Special Procedures for Pulmonary Disease in the Emergency Department

In the emergency department, there are infrequent but essential procedures related to pulmonary diseases that emergency physicians must be able to perform. These include thoracentesis, chest tube thoracostomy, tracheostomy manipulation, and fiberoptic intubation.

Advantages of ketamine in pediatric anesthesia

Although ketamine is primarily used for induction and maintenance of general anesthesia, it also presents sedative, amnestic, anesthetics, analgesic, antihyperalgesia, neuroprotective, anti-inflammatory, immunomodulant, and antidepressant effects. Its unique pharmacodynamics and pharmacokinetic properties allow the use of ketamine in various clinical settings including sedation, ambulatory anesthesia, and intensive care practices. It has also adopted to manage acute and chronic pain management. Clinically, ketamine produces dissociative sedation, analgesia, and amnesia while maintaining laryngeal reflexes, with respiratory and cardiovascular stability. Notably, it does not cause respiratory depression, maintaining both the hypercapnic reflex and the residual functional capacity with a moderate bronchodilation effect. In the pediatric population, ketamine can be administered through practically all routes, making it an advantageous drug for the sedation required setting such as placement of difficult vascular access and in uncooperative and oppositional children. Consequently, ketamine is indicated in prehospital induction of anesthesia, induction of anesthesia in potentially hemodynamic unstable patients, and in patients at risk of bronchospasm. Even more, ketamine does not increase intracranial pressure, and it can be safely used also in patients with traumatic brain injuries. This article is aimed to provide a brief and practical summary of the role of ketamine in the pediatric field.

Comparative Study of Intranasal Dexmedetomidine Versus Intranasal Ketamine as Premedicant in Children

Background: Pre-operative anxiety in children not only makes induction difficult but it is also associated with an increase in the requirement of analgesics, the incidence of post-operative nausea and vomiting (PONV), emergence delirium (ED), and postoperative maladaptive behavioral changes. It can be reduced effectively by pharmacological interventions. In a quest to find the ideal premedicant and non-invasive way of its administration, we decided to compare intranasal (IN) dexmedetomidine with IN ketamine as a premedicant in pediatric patients.

Aims and objectives: To compare sedation score, mask acceptance score (MAS) during induction, the incidence of ED, and other adverse events in both groups.

Material and methods: Some 60 children, between 1 and 8 years of age of either sex undergoing surgical procedures were included in this study and randomly divided into two groups (Group D and Group K). Thirty minutes prior to induction of anesthesia, patients of Group D received dexmedetomidine 1 mcg kg^-1 in 1 mL of 0.9% saline intranasally and patients of Group K received ketamine 5 mg kg^-1 in 1 mL of 0.9% saline intranasally through calibrated dropper (0.5 mL in each nostril) in a recumbent position. Incidences of sneezing or coughing after IN administration of study drugs were recorded. The subsequent sedation scores were assessed using MOASS at 15 min, then at 30 min following premedication at the time of parental separation. After shifting patients to operation theater inhalation induction was done. MAS at induction and any adverse effects were recorded.

Results: Children in Group K were found to be significantly more sedated at 30 min after administration of premedication and mask acceptance was also better (p value < 0.0001 with a confidence interval, CI=95%). But the incidence of ED and PONV was high.

Conclusion: Intranasal dexmedetomidine (1 mcg kg^-1) is clinically less effective as a premedicant in terms of sedation and mask acceptance in older children as compared to ketamine (5 mg kg^-1), but associated with fewer incidence of ED and PONV. We recommend the usage of IN dexmedetomidine in a higher dose (1.5-2 mcg kg^-1), through nebulization/atomizer for the desired level of sedation and mask acceptance.

Near ideal anesthetic technique for tracheal stenting in central airway obstruction with dexmedetomidine-ketamine infusion: a case report

Central airway obstruction presents as an emergency with dyspnea and stridor. Anesthetic management of rigid bronchoscopy-guided tracheal stenting is highly stimulating procedure requiring general anesthesia. But it may lead to life threatening airway obstruction and cardiovascular collapse after induction. Total intravenous anesthesia based on propofol-remifentanil is an optimal anesthetic technique, but remifentanil is not available in many countries. Although dexmedetomidine-ketamine has been used for procedural sedation, its use for rigid bronchoscopy in the setting of central airway obstruction has not been described in literature. We describe near ideal anesthetic technique for management of central airway obstruction using dexmedetomidine-ketamine combination.

Comeback of ketamine: resurfacing facts and dispelling myths

Initially known as CI-581, ketamine was first synthesized in 1962 as a replacement from phencyclidine. It has since been used as an anesthetic and analgesic. In addition, it has bronchodilating, sedative, and amnestic properties, preserving airway reflexes and sympathetic nervous system tone. Since the discovery of ketamine, it has been a major topic of discussion due to controversies regarding its usage in particular sets of patients. In the past 50 years, despite its potential benefits, it is not commonly used because of concerns of "emergence phenomenon," its use as a substance of abuse, and its systemic side effects. Since 2012, three World Health Organization reviews on ketamine have addressed its international control. Researchers have been studying this wonder drug for a decade worldwide. Many myths of ketamine regarding emergence phenomenon and its use in traumatic brain injury and open eye injury have been disproved in recent times. It is becoming popular in pre-hospital settings, critical care, emergency medicine, low-dose acute pain services, and adjuvant in regional anesthesia techniques. This review highlights the current consensus on the various applications of ketamine in the literature.

Intubating conditions and hemodynamic changes during awake fiberoptic intubation using fentanyl with ketamine versus dexmedetomidine for anticipated difficult airway: a randomized clinical trial

Background and objectives

Awake fiberoptic intubation (AFOI) is usually performed in patients with an anticipated difficult airway. Various sedation regimens are used during AFOI, however, most of them cause respiratory depression. The present study aims to compare the effectiveness of fentanyl with ketamine versus dexmedetomidine in search of a better sedation regimen which would achieve desirable intubating conditions and hemodynamic stability without causing respiratory depression.

Methods

This is a single centered randomized, double-blind clinical trial. Patients of both sexes between age 18–55 years and ASA (American Society of Anesthesiologists) physical status I–II with an anticipated difficult airway were randomly divided into two groups of thirty each. Group FK patients received intravenous fentanyl and ketamine, and group DX patients received dexmedetomidine, until Ramsay sedation scale ≥ 2. Heart rate (HR), mean blood pressure (MBP), oxygen saturation (SpO₂), respiratory rate (RR), endoscopy time, intubation time, first end-tidal carbon dioxide (ETCO₂) after intubation, endoscopist satisfaction score, and patient discomfort score were recorded during the study period. The level of recall was assessed on the next postoperative day.

Results

Endoscopist satisfaction score was better in group DX patients (p < 0.05). There was a smaller variation in HR and MBP from baseline with dexmedetomidine compared to fentanyl with ketamine. First ETCO₂ after intubation was higher in group FK patients (p <  0.05). No significant difference was found in patient discomfort score, intubation time, RR, SpO₂ and level of recall of the event.

Conclusions

The use of dexmedetomidine in AFOI provides better intubating conditions and hemodynamic stability compared to fentanyl with ketamine.

Comparative Effects of Dexmedetomidine and Midazolam on Dreaming of Patients Undergoing Flexible Bronchoscopy During General Anesthesia

Background

The aim of this study was to compare the effects of dexmedetomidine versus midazolam on the dreaming of patients undergoing flexible bronchoscopy during general anesthesia.

Material/Methods

Patients undergoing flexible bronchoscopy under general anesthesia were randomly divided into a dexmedetomidine group (Group D, n=40) and a midazolam group (Group M, n=40). In group D, patients received 0.5 μg/kg dexmedetomidine and in group M patients received 0.05 mg/kg midazolam intravenously 10 min prior to induction. After bronchoscopy and recovery, a modified Brice questionnaire was used to immediately evaluate the incidence of dreaming of patients. Dreamers were required to complete a 5-point Likert scale survey regarding the contents of their dreams (emotion, voice and movement, memorability) if dreaming was reported. Ramsay Sedation Scale score (Ramsay score) and Visual Analogue Scale (VAS) score were assessed and recorded.

Results

Patients in group D had higher Ramsay scores and VAS scores (2.9±0.6 and 79.4±4.0, respectively) than group M (2.4±0.7 and 75.0±6.0, respectively), with a statistically significant difference (P<0.05) between groups. The incidence and memorability of dreaming were significantly lower in group D (17.5%) than group M (37.5%, P<0.05), whereas no significant difference was found in emotion, voice, and movement scores of dreaming.

Conclusions

Compared to midazolam, pre-injection of dexmedetomidine before induction significantly decreased the incidence of dreaming in patients undergoing flexible bronchoscopy during general anesthesia, without producing undesirable effects on the content of dreams (most of them were pleasant), produces a more efficacious sedation effect during the recovery period and improves the comfort level and satisfaction of patients.

Airway management of angioedema patients during the COVID-19 pandemic

Importance

The COVID-19 pandemic is characterized by high transmissibility from patients with prolonged minimally- or asymptomatic periods, with a particularly increased risk of spread during aerosol-generating procedures, including endotracheal intubation.

Observations

All patients presenting with upper airway obstruction due to angioedema during this time should be carefully managed in a way that is safest for both patient and provider.

Conclusions

For patients requiring emergent airway management during the COVID-19 pandemic, minimization of aerosols while taking the necessary precautions to protect healthcare workers should are critical principles for their management.

Continuous Rate Infusion of Ketamine Hydrochloride and Dexmedetomidine for Maintenance of Anesthesia during Laryngotracheal Surgery in New Zealand White Rabbits (Oryctolagus cuniculus)

New Zealand white rabbits (Oryctolagus cuniculus) are an established in vivo model for the study of structural and functional consequences of vocal-fold vibration. Research design requires invasive laryngotracheal procedures, and the presence of laryngospasms or pain responses (or both) hinder phonation-related data collection. Published anesthesia regimens report respiratory depression and muscle tone changes and have been unsuccessful in mitigating autonomic laryngeal responses in our protocol. Infusion of ketamine hydrochloride and dexmedetomidine hydrochloride in pediatric medicine provides effective analgesia and sedation for laryngotracheal procedures including intubation and bronchoscopy; however, data evaluating the use of ketamine-dexmedetomidine infusion in rabbits are unavailable. This study reports a new infusion regimen, which was used in 58 male New Zealand white rabbits that underwent a nonsurvival laryngotracheal procedure to induce phonotraumatic vocal-fold injury. Animals were sedated by using ketamine hydrochloride (20 mg/kg IM) and dexmedetomidine (0.125 mg/kg IM). Maintenance anesthesia was provided by using continuous rate intravenous infusion of ketamine hydrochloride (343 μg/kg/min) and dexmedetomidine (1.60 μg/kg/min). A stable plane of anesthesia with no autonomic laryngeal response (laryngospasm) was achieved in 32 of the 58 rabbits (55%). Laryngospasms occurred in 25 of 58 animals (43%) and were controlled in 20 cases (80%) by providing 0.33 mL 2% topical lidocaine, incremental increase in infusion rate, or both. Continuous rate infusion of ketamine hydrochloride-dexmedetomidine with prophylactic topical lidocaine provides a predictable and adjustable surgical plane of anesthesia, with minimal confounding respiratory and autonomic laryngeal responses, during extended-duration laryngotracheal surgery in rabbits. This regimen should be considered as an alternative to injection maintenance for prolonged, invasive procedures.

A comparison of two doses of ketamine with dexmedetomidine for fiberoptic nasotracheal intubation

Background and Aims:

Flexible fiber-optic intubation is considered to be the gold standard for management of difficult airway. Fiber-optic intubation does require effective sedation and blunting of airway reflexes for which various drug regimens have been utilized in the past. In a quest to find the noble drug combination, we combined ketamine and dexmedetomidine in two different doses, to evaluate the clinical efficacy and safety profile of ketamine and dexmedetomidine for fiber-optic intubation.

Materials and Methods:

This prospective randomized study was conducted in 72 patients of 20–50 years’ age group of either sex with the American Society of Anesthesiologists Physical Status I and II with difficult airway. We compared two doses of ketamine 20 mg (Group I) and 40 mg (Group II) with a common dose of dexmedetomidine at 1 μg/kg body weight, given as an infusion over 10 min (a solution of 50 ml with normal saline). Sedation scores, hemodynamic variables in terms of blood pressure, heart rate (HR), and oxygen saturation were studied along with 24-h postoperative patient discomfort and recall of procedure.

Results:

Group II patients showed less variation from their baseline values in terms of HR (ranged between 0.73% and 4.75%) and mean arterial pressure (ranged between 0% and 3.97%) in comparison to Group I HR (ranged between 0.09% and 9.81%) and mean pressures (ranged between 0.3% and 10.38%). Discomfort during procedure (P < 0.001) and recall of procedure scale (P = <0.001) were found significantly better/lower in Group II as compared to Group I.

Conclusion:

Ketamine 40 mg in comparison to 20 mg with dexmedetomidine provides better hemodynamic conditions with better tolerance and lower recall to the fiber-optic intubation.

Efficacy of Adding Low-Dose Ketamine to Dexmedetomidine Versus Low-Dose Ketamine and Propofol for Conscious Sedation in Patients Undergoing Awake Fiber-optic Intubation

Background and Aims:

Conscious sedation is the key for successful AFOI. This trial was conducted to compare the effectiveness of dexmedetomidine and low dose of ketamine against propofol and low dose ketamine.

Materials and Methods:

Sixty patients subjected for general anesthesia were invited to participate in the study and randomly allocated into two equal groups: D-K (n = 30) had been received a bolus dose of both ketamine 0.5mg /kg and dexmedetomidine 1ug/kg over 10 min. Then continuous infusion of ketamine 0.5mg /kg and dexmedetomidine 1ug/kg. The second group (P-K group) (n = 30): had been received a bolus dose of both ketamine 0.5mg/kg and propofol 1mg/kg over 10 min. Then continuous infusion of ketamine 0. 5mg/kg and propofol 1mg/kg.

Results:

The intubation time was statistically significant shorter within the D-K group (58.9 ± 6.1) versus P-K group (63.4 ± 5.3) with p-value 0.02. The shorter time needed to achieve the OAA/S score = 2 was in the D-K group (2.25 ± 0.75) versus (2.9 ± 0.79) in P-K group with (P-value 0.004). The intubation scores were insignificant different between both groups except vocal cord opening which was statistical better among D-K group with P-value 0.03. The significant hypotensive recorded data were among P-K group while the decreased heart rate were recorded in D-K group. Eighty percentages of patients had excellent score of satisfaction within the D-K gp against 47% among the patients within P-K gp with P-value 0.01.

Conclusion:

The concomitant administration of low dose of ketamine with dexmedetomidine had better intubation time and sedation scores with higher patient satisfaction scores than the combination of propofol and low dose of ketamine.

Pediatric premedication: a double-blind randomized trial of dexmedetomidine or ketamine alone versus a combination of dexmedetomidine and ketamine

Background

Preoperative anxiety is common in pediatric patients. When dexmedetomidine is used alone for sedation as premedication, children tend to awaken when separated from their parents, and body movements occur during invasive procedures. We tested the hypothesis that the combination of dexmedetomidine and ketamine may be a useful premedication to alleviate preoperative anxiety and improve cooperation during intravenous cannulation in pediatric patients, while producing minimal adverse events.

Methods

A total of 135 children, aged 2–5 years and American Society of Anesthesiologists status I–II, scheduled for eye surgery were randomly allocated to receive intranasal dexmedetomidine 2.5 μg/kg (group D), oral ketamine 3 mg/kg and intranasal dexmedetomidine 2 μg/kg (group DK), or oral ketamine 6 mg/kg (group K) 30 min before surgery. Sedation state was evaluated every 10 min after premedication and emotional state was assessed during separation from their parents and peripheral intravenous cannulation. Adverse events were recorded for 24 h postoperatively. The primary endpoint was the rate of successful intravenous cannulation.

Results

The rate of successful venous cannulation was 47% with dexmedetomidine alone, 68% with ketamine alone, and 80% with combined premedication (P = 0.006). The rate of satisfactory separation from parents was not different among groups. The incidence of adverse events was higher in group K compared with the other two groups (postoperative vomiting, P = 0.0041; respiratory-related complications during the perioperative period, P = 0.0032; and postoperative psychological/psychiatric adverse events, P = 0.0152).

Conclusion

The combination of intranasal dexmedetomidine 2 μg/kg and oral ketamine 3 mg/kg produces satisfactory separation from parents and more successful venous cannulation, allowing children to smoothly accept induction of general anesthesia.

Trial registration

Chinese Clinical Trial Register (Unique identifier: ChiCTR-TRC-14004475, Date of registration: 2 April 2014).

Evaluation of different doses of dexmedetomidine alone versus the combination of dexmedetomidine and fentanyl in sedation during awake fiberoptic intubation in oral cancer surgery patients: A prospective, randomized, double-blind clinical trial

BACKGROUND

Awake fiberoptic intubation (AFOI) is one of the principal techniques in the management of difficult airway in oral cancer surgery. We hypothesized that the addition of a small dose of fentanyl could improve the sedative criteria of dexmedetomidine during AFOI technique, without the need to increase the dose of dexmedetomidine which may be associated with airway compromise.

PATIENTS AND METHODS

One hundred and fifty American Society of Anesthesiologists physical status 1 and 2 patients planned for AFOI for oral cancer surgery patients were allocated into three groups (fifty patients each). Group D1: Received an infusion of 1 μcg/kg dexmedetomidine diluted in 50 ml saline over 20 min. Group D2: Received an infusion of 2 μcg/kg dexmedetomidine diluted in 50 ml saline over 20 min. Group DF: Received an infusion of 1 μcg/kg dexmedetomidine added to 1 μcg/kg fentanyl diluted in 50 ml saline over 20 min. AFOI was done by topical anesthesia and with the same technique in all patients. All patients were assessed for: airway obstruction, intubation scores (vocal cord movement, coughing, and limb movement), fiberoptic intubation scores, and hemodynamic variables. Any episode of bradycardia or hypoxia was recorded and managed.

RESULTS

Group D2 showed more incidence of airway obstruction than the other two groups. Limb movement scores were more in Group D1 compared to the other two groups. All groups were comparable as regard fiberoptic intubation scores, coughing, and vocal cord opening scores.

CONCLUSION

Adding a low dose of fentanyl (1 μcg/kg) to a low dose of dexmedetomidine can prevent the risk of airway obstruction associated with increasing the dose of dexmedetomidine while achieving the same favorable intubation scores.

Dexmedetomidine versus remifentanil for sedation during awake intubation using a Shikani optical stylet: a randomized, double-blinded, controlled trial

Background

The purpose of this study was to compare the efficacy and safety of dexmedetomidine versus remifentanil for sedation during awake intubation using a Shikani optical stylet (SOS).

Methods

Sixty-eight patients with cervical trauma or severe cervical spondylosis undergoing cervical spinal surgery were enrolled in this prospective study. They were randomly assigned to receive dexmedetomidine (Group D) or remifentanil (Group R). In Group D, the patients received an intravenous loading dose of dexmedetomidine 1 μg · kg⁻¹ over 10 min followed by a continuous infusion of 0.7 μg · kg⁻¹ · h⁻¹. In Group R, a target-controlled infusion of remifentanil was administered to achieve a plasma concentration of 2.5 ng · ml⁻¹, increased to 3 ng · ml⁻¹ 10 min later. An endotracheal tube was inserted using a SOS under dexmedetomidine or remifentanil sedation after topical anesthesia to the airway. Midazolam was given as rescue sedation. We recorded the first attempt intubation success rate, the dose of midazolam, duration of intubation, Ramsay Sedation Scale (RSS) score, tracheal tube tolerance score, duration of drug infusion, adverse events and patient satisfaction score.

Results

The RSS score was significantly higher in Group D than in Group R. First attempt success rate, rescue midazolam dose and the duration of intubation did not differ between the groups. Patients in Group R were significantly more tolerant of the tracheal tube. The incidence of hypoxia was significantly higher in Group R than Group D, but there was no significant difference in the incidence of other adverse events between the groups. The hemodynamic responses of the two groups were similar, but more patients in Group R were able to recall airway instrumentation.

Conclusions

Both dexmedetomidine and remifentanil are effective sedatives for awake intubation using an SOS. Although the first attempt success rates were similar, patients sedated with remifentanil tolerated the tracheal tube better after intubation with moderately increased risk of desaturation.

Trial registration

www.chictr.org.cn; ChiCTR-TRC-13003052 (February 4th, 2013).