A Randomized Controlled Study Comparing Dexmedetomidine-Midazolam with Fentanyl-Midazolam for Sedation during awake Fiberoptic Intubation in Anticipated Difficult Airway

Antinociceptive Agents as General Anesthetic Adjuncts: Supra-additive and Infra-additive Interactions

The hypothesis "General anesthesia consists of producing both loss of consciousness and the inhibition of noxious stimuli reaching the brain and causing arousal" was used as a basis for the review of published data on general anesthetic interactions with antinociceptive agents: opioids, α 2 adrenergic agonists, and systemic sodium channel blockers. This review is focused on a specific type of anesthetic interaction-the transformation of antinociceptive agents into general anesthetic adjuncts. The primary aim is to answer 2 questions. First, how does an antinociceptive agent transform the effect of an anesthetic in providing a certain component of anesthesia-hypnosis, immobility, or hemodynamic response to noxious stimulation? Second, does a combination of an anesthetic with an adjunct result in a simple summation of their respective effects or in a supra-additive or infra-additive interaction? The Medline database was searched for data describing the interactions of antinociceptive agents and general anesthetics. The following classes of antinociceptive agents were considered: opioids, α 2 adrenergic agonists, and systemic sodium channel blockers. Drugs used in combination with antinociceptive agents were general anesthetics and benzodiazepines. The following terms related to drug interactions were used: anesthetic interactions, synergy, antagonism, isobolographic analysis, response surface analysis, and fractional analysis. The interactions of antinociceptive agents with general anesthetics result in a decrease of general anesthetic requirements, which differ for each of the components of general anesthesia: hypnosis, immobility, and hemodynamic response to noxious stimulation. Most studies of the nature of anesthetic interactions are related to opioid-general anesthetic combinations, and their conclusions usually confirm supra-additivity.

Comparative review of airway anesthesia and sedation methods for awake intubation

PURPOSE OF REVIEW

Successful awake intubation hinges upon adequate airway anesthesia and sedation for patient comfort. This review will summarize relevant anatomy and regional anesthesia techniques to achieve airway anesthesia, and compare various airway anesthesia and sedation regimens.

RECENT FINDINGS

Overall, nerve blocks consistently provided superior airway anesthesia, shorter time to intubation, higher patient comfort, and higher postintubation patient satisfaction. Additionally, ultrasound guidance can further provide benefit by reducing the amount of local anesthetic administered, leading to denser blockade, and proving invaluable in challenging clinical situations. Regarding sedation methods, numerous studies supported the use of dexmedetomidine, with or without the addition of supplemental sedation, such as midazolam, ketamine, or opioids.

SUMMARY

Emerging evidence has indicated that nerve blocks for airway anesthesia may be superior to other methods of topicalization. Additionally, dexmedetomidine can be useful, both as monotherapy and with supplemental sedatives, to safely provide anxiolysis for the patient and increase success. However, it is crucial to note that the method of airway anesthesia and sedation regimen should be adapted to each patient and clinical situation, and knowledge of multiple techniques and sedation regimens can best equip anesthesiologists to do so.

Pharmacotherapy optimization for rapid sequence intubation in the emergency department

PURPOSE

Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods.

SUMMARY

There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use.

AREAS FOR FUTURE RESEARCH

The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

Comparison of dexmedetomidine alone with dexmedetomidine and fentanyl during awake fiberoptic intubation in patients with difficult airway: a randomized clinical trial

Background

Awake fiberoptic intubation (AFOI) is the procedure of choice for securing the airway in patients with a difficult airway when undergoing surgeries under general anesthesia. An ideal drug would not only provide conscious sedation but also maintain spontaneous ventilation, smooth intubation conditions, and stable hemodynamics. We compared the effects of dexmedetomidine alone and dexmedetomidine in combination with fentanyl at a dose lower than the standard dose for achieving conscious sedation during AFOI in difficult airway patients undergoing oral cancer and dental surgeries.

Methods

We included 68 adult patients undergoing AFOI. The patients were randomized in two groups, wherein Group D received intravenous dexmedetomidine 1 µg/kg and Group DF received dexmedetomidine 0.5 µg/kg and fentanyl 1 µg/kg. The outcomes measured were airway obstruction score, intubation scores, fiberoptic intubation comfort score, sedation score, and hemodynamic variables.

Results

Low-dose dexmedetomidine with fentanyl showed similar results as those with the standard dose of dexmedetomidine in terms of airway obstruction, vocal cord movement, degree of cough, degree of limb movements, and intubation comfort. However, the sedation achieved and incidence of hypotension and bradycardia were higher in Group D than in Group DF.

Conclusions

A low dose of dexmedetomidine–fentanyl provides satisfactory intubation conditions as those with a standard dose of dexmedetomidine in AFOI, thereby avoiding bradycardia, hypotension, and sedation.

Endogenous opiates and behavior: 2020

This paper is the forty-third consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2020 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Comparison between Intravenous Dexmedetomidine and Spray as you Go with 4% Lignocaine Versus Intravenous Fentanyl and Transtracheal Injection of 4% Lignocaine for Awake Nasotracheal Intubation with Flexible Vedioscope - A Randomized Single-Blind Prospective Study

Background

Awake fiber-optic bronchoscopy-guided intubation is the method of choice in difficult airway which requires effective airway anesthesia to ensure patient comfort and acceptance.

Aims

This study was conducted to assess the quality of airway anesthesia, patient comfort during intubation, and postoperative satisfaction of patients.

Settings

Patients posted for surgeries under general anesthesia with Mallampati Grade I and II in a medical college. Patients were followed in the operation theater and postoperative ward.

Study Design

This was a prospective randomized single-blind study.

Materials and Methods

Group D received intravenous (i.v.) dexmedetomidine 1 μg.kg-1 i.v. over 10 min and 3 ml of 4% lignocaine spray as you go (SAYGo). Group F received i.v. fentanyl 2 μg.kg-1 over 10 min and transtracheal injection 3 ml of 4% lignocaine. Parameters assessed were endoscopic time, intubating condition, vocal cord position, cough severity, comfort during intubation, postoperative patient satisfaction, and any adverse effects such as sore throat, hoarseness, unpleasant memories, and hemodynamic response during intubation.

Statistical Analysis

Independent Student's t-test, Mann-Whitney, Chi-squared test, or Fisher's exact test were used. P ≤ 0.05 was considered statistically significant.

Results

Intubating conditions, vocal cord position, cough severity, comfort during intubation, and postoperative patient satisfaction were statistically significant (P ≤ 0.05) in favor of Group D though endoscopic time was longer.

Conclusion

IV dexmedetomidine with SAYGo is effective than IV fentanyl with transtracheal block for awake fiber-optic videoscopic intubation in terms of intubating conditions, vocal cord position, cough severity, comfort during intubation, and postoperative satisfaction of patients with significant attenuation of postintubation hemodynamic response and better preservation of respiration though endoscopic time is more.