Mechanisms and treatment of laryngospasm

Comparing the effectiveness of topical dexamethasone emollient, lidocaine gel, and glycerin emollient on the endotracheal tube for postoperative hoarseness of voice, sore throat, and laryngospasm

During general anesthesia, inserting a relatively stiff endotracheal tube using a metallic laryngoscope through the soft tissues of the pharynx and larynx, along with applying a pressured cuff, can result in varying degrees of tissue trauma and adverse outcomes. Anesthesiologists commonly encounter post-operative issues such as hoarseness, sore throat, and laryngospasm. This study aimed to compare the effectiveness of topical applications of dexamethasone emollient, lidocaine gel, and glycerin emollient in reducing these complications. One hundred patients were randomly assigned to four groups of 25 patients each: the control group (Group C), lidocaine gel group (Group L), glycerin emollient group (Group G), and dexamethasone emollient group (Group D). The assigned medication was topically applied to the endotracheal tube, and patients were monitored for postoperative laryngospasm, hoarseness, and sore throat within the first 24 hours. No statistically significant differences were found among the four groups in terms of demographic characteristics, postoperative sore throat, hoarseness, or laryngospasm (p>0.05). Lidocaine gel was an effective drug that can be used to attenuate the incidence rate of post-operative sore throat.

Effects of continuous and slow tracheal tube cuff deflation on cough reflex during extubation in noncardiac surgery patients: a randomised clinical trial

BACKGROUND

The incidence of cough reflex during extubation is 76%. Cough reflex causes severe hemodynamic fluctuations and airway complications. This prospective trial investigated the potential effects of tracheal tube cuff deflation on cough reflex during extubation.

METHODS

One hundred and twenty-six patients scheduled for operations within 3 h under general anaesthesia with orotracheal intubation were randomly assigned to one of three groups: control (C), experimental (E) or syringe (S) groups. Patients in group C underwent tracheal tube cuff deflation using a 10-ml syringe in 1 s, patients in group E underwent tracheal tube cuff deflation continuously and slowly in 5 s using a cuff pressure gauge until the pressure was zero and patients in group S underwent tracheal tube cuff deflation using a 10-ml syringe at a speed of 1 ml s^-1. The incidence and severity of cough reflexs during extubation and the incidence of postoperative airway complications within 48 h were assessed.

RESULTS

Compared with group C (60.0%), the incidence of cough reflex in group E was 9.8% (p < 0.001) and in group S was 12.5% (p < 0.001). The severity of cough reflex was graded as 2 (1-2) in group C, 1 (1-1) in group E and 1 (1-1) in group S (p < 0.001 for group comparisons). The incidence of hoarseness in group C was 0.0%, in group E was 19.5% and in group S was 5.0% (p < 0.05 for all groups, p = 0.009 between group C and E).

CONCLUSIONS

Compared with deflating a trachal tube cuff with a 10-ml syringe in 1 s, the use of a 10-ml syringe at a speed of 1 ml s^-1 or a cuff pressure guage within 5 s can both reduce the incidence of cough reflex, but deflating with a cuff pressure guage can increase the incidence of postoperative hoarseness.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier: ChiCTR2100054089, Date: 08/12/2021.

Laryngeal reflex responses in pediatric anesthesia

Laryngeal and respiratory reflexes are vitally important defense mechanisms against foreign body aspiration, safeguarding airway patency, and ventilation. These highly preserved automatisms easily overrule external influences like willpower or (anesthetic) medication. Prevention and anticipation are, therefore, the essential strategies to avoid adverse events and damage, and treatment is most effective in the early stage of the reflex response. The physiology and pathophysiology of the various defensive reflexes as well as a comprehensive anesthetic approach to prevention and treatment are outlined in this review.

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.

Muscles of Breathing: Development, Function, and Patterns of Activation

This review is a comprehensive description of all muscles that assist lung inflation or deflation in any way. The developmental origin, anatomical orientation, mechanical action, innervation, and pattern of activation are described for each respiratory muscle fulfilling this broad definition. In addition, the circumstances in which each muscle is called upon to assist ventilation are discussed. The number of "respiratory" muscles is large, and the coordination of respiratory muscles with "nonrespiratory" muscles and in nonrespiratory activities is complex-commensurate with the diversity of activities that humans pursue, including sleep (8.27). The capacity for speech and adoption of the bipedal posture in human evolution has resulted in patterns of respiratory muscle activation that differ significantly from most other animals. A disproportionate number of respiratory muscles affect the nose, mouth, pharynx, and larynx, reflecting the vital importance of coordinated muscle activity to control upper airway patency during both wakefulness and sleep. The upright posture has freed the hands from locomotor functions, but the evolutionary history and ontogeny of forelimb muscles pervades the patterns of activation and the forces generated by these muscles during breathing. The distinction between respiratory and nonrespiratory muscles is artificial, as many "nonrespiratory" muscles can augment breathing under conditions of high ventilator demand. Understanding the ontogeny, innervation, activation patterns, and functions of respiratory muscles is clinically useful, particularly in sleep medicine. Detailed explorations of how the nervous system controls the multiple muscles required for successful completion of respiratory behaviors will continue to be a fruitful area of investigation. © 2019 American Physiological Society. Compr Physiol 9:1025-1080, 2019.

Transtracheal Lignocaine: Effective Treatment for Postextubation Stridor

Three cases of postextubation stridor due to suspected laryngospasm are described in which a small dose of lignocaine injected intra-tracheally, through the cricothyroid membrane, produced rapid and effective relief of stridor with no early recurrence or side-effects. The procedure was performed safely and quickly and was well tolerated by patients. Transtracheal injection of local anaesthetic should be considered for treatment of postextubation stridor in adults, so long as there is no risk of pulmonary aspiration, and pathological causes of laryngospasm have been excluded.

Pulmonary edema post-adenotonsillectomy in children

Post-adenotonsillectomy pulmonary edema (pATPE) is a life-threatening condition that necessitates immediate clinical intervention. The early diagnosis and detection of the signs of this condition is vital to its treatment and patient outcome. The purpose of this review article is to present epidemiological data on the prevalence of pATPE, and address the mechanisms of development, types, etiology, pathophysiology, and management of pATPE. In order to minimize postoperative intensive care unit admission rates of pATPE, utilization of preoperative clinical assessment, operative/postoperative monitoring tools, and procedural precautions are discussed.

Postoperative negative pressure pulmonary edema following repetitive laryngospasm even after reversal of neuromuscular blockade by sugammadex: a case report

Laryngospasm, an occlusion of the glottis, can occur at any time during anesthesia, and is associated with serious perioperative complications such as hypoxia, hypercabia, aspiration, bronchospasm, arrhythmia, prolonged recovery, cardiac collapse, and eventually catastrophic death. Importantly, postoperative negative pressure pulmonary edema (NPPE) is a rare, but well described life-threatening complication related to acute and chronic upper airway obstruction. Sugammadex well known for affirmatively reducing the postoperative pulmonary complications associated with residual neuromuscular blockade may have an indirect role in triggering the negative intrathoracic pressure by raising a rapid and efficacious respiratory muscle strength in acute upper airway obstruction. Herein, we report a case of postoperative NPPE following repetitive laryngospasm even after reversal of rocuronium-induced neuromuscular blockade using sugammadex.

Hemodynamic and related challenges: monitoring and regulation in the postoperative period

The clinician caring for patients in the immediate postoperative period must maintain a high index of suspicion for the development of complications. Evolving illness manifests itself throughout the continuum of care and must be recognized and aggressively managed to ensure optimal outcome. This article discusses common hemodynamic problems encountered in the postanesthesia care unit. These problems are presented in a clinical framework that is familiar to experienced practitioners and recognizable to trainees. This article reviews of these common problems including relevant physiologic principles; effects on hemodynamics; and a logical approach to evaluation, monitoring, and management of a complex postoperative patient.

Difficult Airway Society Guidelines for the management of tracheal extubation

Tracheal extubation is a high-risk phase of anaesthesia. The majority of problems that occur during extubation and emergence are of a minor nature, but a small and significant number may result in injury or death. The need for a strategy incorporating extubation is mentioned in several international airway management guidelines, but the subject is not discussed in detail, and the emphasis has been on extubation of the patient with a difficult airway. The Difficult Airway Society has developed guidelines for the safe management of tracheal extubation in adult peri-operative practice. The guidelines discuss the problems arising during extubation and recovery and promote a strategic, stepwise approach to extubation. They emphasise the importance of planning and preparation, and include practical techniques for use in clinical practice and recommendations for post-extubation care.

Laryngospasm: review of different prevention and treatment modalities

Laryngospasm is a common complication in pediatric anesthesia. In the majority of cases, laryngospasm is self-limiting. However, sometimes laryngospasm persists and if not appropriately treated, it may result in serious complications that may be life-threatening. The present review discusses laryngospasm with the emphasis on the different prevention and treatment modalities.

Pediatric laryngospasm

Pediatric laryngospasm is an anesthetic emergency. It is a relatively common phenomenon that occurs with varying frequency dependent on multiple factors. In view of this and the clear risks to the patient when it occurs, a consensus committee has been established to determine the evidence based management of this condition. This article will cover the definition, causes and recognition of laryngospasm and the evidence behind a proposed algorithm for its' management.

Sedation-analgesia in the pediatric intensive care unit

The provision of sedation and analgesia is an integral aspect of the care of PICU patients. A careful systems approach to the provision of sedation and analgesia can minimize complications and maximize benefit to patients. Vigilance in monitoring and adherence to published guidelines are important for safety. Physicians must define the goals in clearly devising a plan and tailor the prescription to those goals rather than use a regimented protocol for all patients.