Topical Pharyngeal Anesthesia in Sedated Pediatric Patients Undergoing Esophagogastroduodenoscopy.

OBJECTIVES: Pediatric patients undergoing esophagogastroduodenoscopy (EGD) commonly receive procedural sedation for comfort and to facilitate the procedure. EGD with procedural sedation carries the risk of several airway incidents and/or adverse events (AIAE). Topical pharyngeal anesthetics (TPAs) can blunt the airway reflexes and decrease the incidence of laryngospasm but has not been well studied with EGD under procedural sedation. We aimed to study the effect of adding a TPA to propofol-based sedation on the rate of AIAE. METHODS: This is a single-center, retrospective, observational cohort study. We compare AIAE rates (coughing, gagging, apnea, airway obstruction, and laryngospasm) in children who received TPA as part of their propofol-based procedural sedation for EGD with those who did not receive TPA. RESULTS: In 2021, 73 patients received TPA as part of the procedural sedation for EGD and 123 did not. The overall rate of AIAE was high with 75 (38%) patients experiencing 1 or more AIAE. Patients who received benzocaine spray experienced more AIAE than the control group [adjusted odds ratio (aOR) = 1.16; 95% confidence interval (CI): 1.01-1.34; P = 0.037]. Coughing, gagging, apnea with desaturation rates, and laryngospasm were similar in both groups (coughing aOR = 1.01; 95% CI: 0.91-1.13; P = 0.814; gagging aOR = 1.01; 95% CI: 0.91-1.13; P = 0.814; apnea aOR = 0.99; 95% CI: 0.95-1.04; P = 0.688; laryngospasm OR = 1.01; 95% CI: 0.95-1.07; P = 0.71). The rate of airway obstruction requiring jaw thrust was higher in the benzocaine group but did not reach statistical significance (aOR = 1.11; 95% CI: 0.97-1.26; P = 0.133). CONCLUSION: The use of topical pharyngeal benzocaine in children undergoing EGD with propofol-based sedation is associated with a higher overall AIAE rate. Most of the AIAE were mild incidents and only 7 patients experienced true adverse events.

Comparison of the effects of intravenous propofol and propofol with low-dose ketamine on preventing postextubation cough and laryngospasm among patients awakening from general anaesthesia: A prospective randomised clinical trial.

BACKGROUND: Coughing and laryngospasm are undesirable consequences occurring when patients awaken from general anaesthesia. The objective of the study aimed to compare the effects of intravenous propofol and propofol with low-dose ketamine on preventing postextubation cough and laryngospasm. METHODS: In all, 120 patients scheduled surgery under general anaesthesia were randomly assigned into three groups. Patients in the control group (C-group) received intravenous 0.9% NaCl, while patients in the propofol group (P-group) received intravenous 0.25mg/kg propofol and patients in the propofol combined with ketamine group (PK-group) received intravenous 0.25mg/kg of propofol plus 0.15mg/kg of ketamine. Drugs were administered before extubation. Incidence and severity of coughing and laryngospasm were recorded by a blinded anaesthesiologist. RESULTS: Subjects of the PK-group (25%) experienced significantly reduced incidence of postoperative cough than that in the P-group (55%) and C-group (72.5%) (all P < 0.05). The severity of cough in the PK-group was significantly less than that in the P-group and C-group (P = 0.039 and P < 0.001, respectively). No significant difference was found in the incidence and severity of laryngospasm between comparison groups. CONCLUSION: Intravenous combination of propofol and low-dose ketamine significantly reduced the incidence and severity among patients awakening from general anaesthesia.

Intraoperative Infusion of Magnesium Sulphate does not Reduce Laryngospasm and Agitation during Emergence from Anaesthesia in Children.

Background Laryngospasm and agitation during emergence from general anaesthesia are frequent in children. Magnesium sulphate may have the potential of reducing both of these adverse events. In addition, magnesium has analgesic and anaesthetic properties. Objective To find out the effectiveness of magnesium sulphate in reducing the occurrence of emergence laryngospasm and agitation and other adverse events if any in children. Method Randomized, placebo controlled study was conducted at a tertiary care hospital in 132 children, aged 3-12 years undergoing general anaesthesia for hernia and hydrocele surgery. Children with American Society of Anaesthesiologist Physical Status > II were excluded. After insertion of laryngeal mask airway, 20 ml of either magnesium sulphate 15 mg/kg (Group M) or normal saline (Group N) was infused at the rate of 1 ml/min. The severity of laryngospasm and agitation was assessed. We also noted other adverse events, if occurred. Result Laryngospasm occurred in 7(10.6%) patients of group M and in 10(15.1%) patients of group N(p=0.40). While 14(10.6%) patients developed laryngospasm immediately after removal of LMA, only 3(2.2%) patients developed it in the post anaesthetic care unit. Two (3.0%) patients of group M and four patients (6.0%) of group N were agitated (p=0.40). Three (4.5%) patients of group M and 14(21.2%) patients of group N coughed during emergence (p=0.004). Conclusion Intraoperative infusion of 15 mg/kg magnesium sulphate, does not reduce the occurrence of emergence laryngospasm and agitation in children. However, it significantly reduce emergence cough.

Original Research: Aerosolized Lidocaine: Effective for Safer Arousal After Suspension Laryngoscopy.

AIM: To examine the systemic and local effects of the lidocaine on the larynx and trachea which is applied after the end of the surgery and through various application methods. STUDY DESIGN: Randomized controlled prospective study. METHOD: The study is composed of patients who underwent suspension laryngoscopy (SL) for benign laryngeal diseases (cysts, polyp, granuloma, etc) and American Society of Anesthesiologists (ASA) I, between January 2017 and January 2018. The patients were randomly divided into 3 groups. In the first group nothing is applied at the end of the surgery and called as control group, second group received 7 pufs of aerosolized 10% lidocaine solution (70 mg) over larynx and trachea and third group received cotton swaps that impregnated in 1 ml of 20 mg lidocaine solution over surgical area for 1 minutes. Operation and arousal times, heart rate and mean arterial blood pressure levels were noted and compared. Also laryngospasm, cough, and agitation scores were obtained during arousal. RESULTS: 64 patients were included in the study. Laryngospasm was not observed in any of the patients. In group 2 (aerosolized lidocaine group), patients' blood pressure remained similar while increased in other groups (P < 0.05). Agitation scores were significantly lower in group 2 compared to the other groups (P = 0.012). Cough reflex is observed less in group 2 but result was not statistically significant (P = 0.13) CONCLUSION: The usage of aerosolized lidocaine after suspension laryngoscopy is very effective in blocking the stimulation of superior laryngeal nerve and sympathetic nerves which were responsible for the pressor reflexes. The inhibition of these reflexes before or during arousal could secure a safer arousal.

Prevention and Treatment of Laryngospasm in the Pediatric Patient: A Literature Review.

Laryngospasm is an exaggeration of a protective reflex that prevents aspiration of foreign objects into the lower airway (eg, during swallowing). This results in complete or partial closure of the glottis, and impedance or total obstruction of airflow to the trachea and lungs. Often, the resulting hypoxia will by itself break a laryngospasm; however, if the spasm continues without relief, it can lead to pulmonary edema, cardiac dysrhythmias, cardiac arrest, and ultimately death. This evidence-based literature review explores the pathophysiology of laryngospasm and covers mechanical and pharmacologic prevention and treatment modalities in pediatric patients.

Effects of dexmedetomidine vs sufentanil during percutaneous tracheostomy for traumatic brain injury patients: A prospective randomized controlled trial.

BACKGROUND: Percutaneous tracheostomy, almost associated with cough reflex and hemodynamic fluctuations, is a common procedure for traumatic brain injury (TBI) patients, especially those in neurosurgery intensive care units (NICUs). However, there are currently a lack of effective preventive measures to reduce the risk of secondary brain injury. The aim of this study was to compare the effect of dexmedetomidine (DEX) vs sufentanil during percutaneous tracheostomy in TBI patients. METHODS: The 196 TBI patients who underwent percutaneous tracheostomy were randomized divided into 3 groups: group D1 (n = 62, DEX infusion at 0.5 µg·kg for 10 minutes, then adjusted to 0.2-0.7 µg·kg·hour), group D2 (n = 68, DEX infusion at 1 µg·kg for 10 minutes, then adjusted to 0.2-0.7 µg·kg·hour), and group S (n = 66, sufentanil infusion 0.3 µg·kg for 10 minutes, then adjusted to 0.2-0.4 µg·kg·hour). The bispectral index (BIS) of all patients was maintained at 50 to 70 during surgery. Anesthesia onset time, hemodynamic variables, total cumulative dose of DEX/sufentanil, total doses of rescue propofol and fentanyl, time to first dose of rescue propofol and fentanyl, number of intraoperative patient movements and cough reflexes, adverse events, and surgeon satisfaction score were recorded. RESULTS: Anesthesia onset time was significantly lower in group D2 than in both other groups (14.35 ±â€Š3.23 vs 12.42 ±â€Š2.12 vs 13.88 ±â€Š3.51 minutes in groups D1, D2, and S, respectively; P < .001). Both heart rate and mean arterial pressure during percutaneous tracheostomy were more stable in group D2. Total doses of rescue propofol and fentanyl were significantly lower in group D2 than in group D1 (P < .001). The time to first dose of rescue propofol and fentanyl were significantly longer in group D2 than in both other groups (P < .001). The number of patient movements and cough reflexes during percutaneous tracheostomy were lower in group D2 than in both other groups (P < .001). The overall incidences of tachycardia and hypertension (which required higher doses of esmolol and urapidil, respectively) were also lower in group D2 than in both other groups (P < .05). Three patients in group S had respiratory depression compared to X in the D1 group and X in the D2 group. The surgeon satisfaction score was significantly higher in group D2 than in both other groups (P < .05). CONCLUSIONS: During percutaneous tracheostomy, compared with sufentanil, DEX (1 µg·kg for 10 minutes, then adjusted to 0.2-0.7 µg·kg·hour) can provide the desired attenuation of the hemodynamic response without increased adverse events. Consequently, DEX could be used safely and effectively during percutaneous tracheostomy in TBI patients.

Topical Pharyngeal Lidocaine Reduces Respiratory Adverse Events During Upper Gastrointestinal Endoscopies Under Ketamine Sedation in Children.

BACKGROUND: Upper gastrointestinal endoscopies (UGEs) performed under ketamine sedation may increase the risk of respiratory adverse events (RAEs) due to pharyngeal stimulation. Topical lidocaine prevents general anesthesia-induced laryngospasm. OBJECTIVE: Our objective was to determine whether topical lidocaine may reduce the incidence of RAEs induced by pharyngeal stimulation in UGEs performed on children sedated with ketamine. METHODS: We conducted a single-center prospective study. We included every patient admitted for an elective diagnostic UGE under ketamine sedation who received lidocaine prior to the technique. Patients requiring any other medication were excluded. Our main outcome measure was the number of desaturation episodes. We then compared these results with those obtained in an historic group who did not receive topical lidocaine, in which we registered a total of 54 desaturation episodes. RESULTS: In total, 88 children (52.3% boys) were included. The median age was 7 years [interquartile range (IQR) 3-11]. The mean duration of the procedure was 6.5 ± 2.4 min, and the median initial ketamine dose was 1.76 mg/kg (IQR 1.56-2.03). The total number of desaturation episodes was 3 (3.4%), and two of these occurred prior to the introduction of the endoscope. This result represents a lower incidence than in previously reported series, and a significant decrease (p < 0.0001) with respect to the 54 RAEs registered in the historic group of 87 children. CONCLUSIONS: Topical lidocaine premedication significantly reduced the incidence of RAEs in children during UGEs under ketamine sedation. Our findings should be confirmed by a double-blind randomized controlled trial.

Efficacy of Adjuvant Magnesium for Posttonsillectomy Morbidity in Children: A Meta-analysis.

Objectives The perioperative administration of magnesium is known to reduce postoperative morbidities in adults, such as pain, agitation, and laryngospasm. The objective is to assess the effects of perioperative magnesium as the adjuvant to tonsillectomy as compared with tonsillectomy in children. Data Source Five databases (PubMed, SCOPUS, Embase, Web of Science, Cochrane). Method Two authors independently searched databases up to January 2017. We compared perioperative magnesium administration (magnesium groups) with no administration of magnesium (control group). The following outcomes were measured: postoperative pain intensity, analgesics administration, or other morbidities (laryngospasm, agitation, postoperative bleeding) in the postoperative 24 hours. Additionally, to evaluate the discrepancy of effects according to different administration routes, subgroup analyses regarding effects according to systemic or local administration of magnesium were performed. Results Nine prospective randomized controlled studies (n = 615) that evaluated the effect of magnesium in children having undergone tonsillectomy met inclusion criteria. Compared with control group, the time for first analgesic requirement was significantly delayed in magnesium groups (standardized mean difference = 0.75; 95% CI, 0.20-1.31; P = .0079). Laryngospasm (log odds ratio = -1.09; 95% CI,-2.11 to -0.07; P = .0362) and agitation score (standardized mean difference = -0.67; 95% CI, -0.97 to -0.36; P < .0001) in the recovery room also significantly decreased in magnesium groups. In subgroup analyses regarding pain and laryngospasm-related measurements, local administration of magnesium was shown to be more effective at reducing postoperative morbidities. Conclusions Perioperative magnesium regardless of route may offer pain, agitation, and laryngospasm relief without adverse effects in pediatric tonsillectomy. Based on the high heterogeneity of results within some parameters, further studies need to be performed to affirm these results.

An update on the perioperative management of children with upper respiratory tract infections.

PURPOSE OF REVIEW: This review summarizes the current evidence for the management of children with recent upper respiratory tract infections (URTIs). Furthermore, the review includes management guidelines for children with URTIs. RECENT FINDINGS: Good history and clinical examination is sufficient in most children presenting with URTI. Testing for immune markers or preoperative nitric oxide measurement does not add any additional value. Preoperative bronchodilator administration, intravenous induction with propofol, and noninvasive airway management all reduce the occurrence of respiratory adverse events. SUMMARY: Most children can be safely anaesthetized even in the presence of an URTIs if the perioperative anaesthesia management is optimized. In this review article, we have included a management algorithm for children with URTI presenting for elective surgery.

Impact of high concentrations of sevoflurane on laryngeal reflex responses.

BACKGROUND: Exaggerated defensive upper airway reflexes, particularly laryngospasm, may cause hypoxemic damage, especially in children. General clinical experience suggests that laryngeal reflex responses are more common under light levels of anesthesia, and previous clinical studies have shown an inverse correlation between laryngeal responsiveness and depth of hypnosis. However, this seems to be less obvious in children anesthetized with sevoflurane. The aim of this study was to assess the impact of high concentrations of sevoflurane on laryngeal and respiratory reflex responses in spontaneously breathing children. Accordingly, we tested the hypothesis that laryngeal and respiratory reflex responses were completely suppressed in spontaneously breathing children when anesthetized with sevoflurane 4.7% (=MACED95Intubation ) as compared with sevoflurane 2.5% (=1 MAC). METHODS: In this prospective observational study, we tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is diminished under high concentrations of sevoflurane. Following Ethics approval, trial registration, and informed consent, 40 children (3-7 years) scheduled for elective surgery participated in the trial. All children received sevoflurane 2.5% (1 MAC) and 4.7% (ED95Intubation ) in random order with 5-min equilibration between the states. Under both conditions, distilled water was sprayed under bronchoscopic view onto the larynx. Potential laryngeal and respiratory reflex responses were assessed offline by a blinded reviewer. RESULTS: Laryngospasm (episodes lasting >10 s) occurred in 12/38 (32%) of the patients anesthetized with sevoflurane 2.5%, vs 7/38 (18%) in those anesthetized with sevoflurane 4.7% (difference: OR 3.5; 95% CI [0.72-16.84], P = 0.18). All other reflex responses (coughing, expiration reflexes, and spasmodic panting) were infrequent and were similar among the examined concentrations. CONCLUSION: Against our hypothesis, laryngospasm could still be observed in 18% of children under the higher concentration of sevoflurane (4.7%, ED95Intubation ).

Adjuncts to local anaesthetics in tonsillectomy: a systematic review and meta-analysis.

The infiltration of local anaesthetic agents has been shown to reduce post-tonsillectomy pain. A number of recent studies have shown that the addition of agents such as clonidine and dexamethasone improve the efficacy of nerve blocks and spinal anaesthesia. The aim of this review was to determine whether additives to local anaesthetic agents improve post-tonsillectomy outcomes. Four major databases were systematically searched for all relevant studies published up to August 2016. All study designs with a control group receiving local anaesthetic infiltration and an intervention receiving the same infiltration with an added agent were included in this review. These studies were then assessed for level of evidence and risk of bias. The data were then analysed both qualitatively and where appropriate by meta-analysis. We reviewed 11 randomised controlled trial (RCTs) that included 854 patients. Due to inconsistencies in the methods used to report outcomes, both quantitative and qualitative comparisons were required to analyse the extracted data. Overall, we found that dexamethasone, magnesium, pethidine and tramadol reduce post-operative pain and analgesia use, with dexamethasone in particular significantly reducing post-operative nausea and vomiting and magnesium infiltration significantly reducing the incidence of laryngospasm. This systematic review of RCTs provides strong evidence that the use of dexamethasone and magnesium as additives to local anaesthetics reduces post-tonsillectomy pain and analgesia requirement. There is limited evidence that pethidine and tramadol have a similar effect on pain and analgesia requirement. The studies in this pooled analysis are sufficiently strong to make a level one recommendation that the addition of magnesium to local anaesthetics reduces the incidence of laryngospasm, a potentially lethal post-operative complication. Review level of evidence: 1.

End-tidal desflurane concentration for tracheal extubation in adults. / Concentración al final de la espiración de desflurano requerida para la extubación en el paciente adulto.

OBJECTIVE: To determine the end-tidal desflurane concentration required for tracheal extubation in anaesthetised adults. MATERIAL AND METHODS: After hospital Ethics Committee approval, eighteen ASA I-II adult patients (19-65 years of age), who had been scheduled for elective ambulatory surgery were included in the study. Anaesthesia was induced with propofol 2.5mg.kg-1, fentanyl 2µg.kg-1, and rocuronium 0.6mg.kg-1 for intubation. Maintenance of anaesthesia was provided by desflurane in oxygen and air (40:60), and remifentanil at 0.05-0.25µg.kg-1.min1. Neuromuscular function was monitored with train-of-four (TOF) nerve stimulation and acceleromyography. At the end of the surgery neuromuscular blockade was reversed with sugammadex 2-4mg.kg-1 in accordance with the TOF ratio. The concentration of desflurane at which extubation was attempted was determined by using Dixon's up-and-down method with 0.5% as a step size. Smooth extubation was defined as one without coughing, teeth clenching, gross purposeful movements, and no breath-holding or laryngospasm within 1min of tracheal extubation. RESULTS: It was found that the end-tidal concentration of desflurane was 3.17±0.18% (95% CI: 3%-3.35%) for successful extubation in 50% of adults. CONCLUSION: Extubation in patients receiving desflurane may be feasible at 0.62 minimum alveolar concentration.

The Efficacy of Lidocaine in Laryngospasm Prevention in Pediatric Surgery: a Network Meta-analysis.

Higher incidence and worse outcomes of laryngospasm during general anesthesia in children than adults have been reported for many years, but few prevention measures are put forward. Efficacy of lidocaine in laryngospasm prevention has been argued for many years and we decided to design this network meta-analysis to assess the efficacy of lidocaine. We conducted an electronic search of six sources and finally included 12 Randomized Controlled Trials including 1416 patients. A direct comparison between lidocaine and placebo revealed lidocaine had the effect on preventing laryngospasm in pediatric surgery (RR = 0.46, 95% CI = [0.30, 0.70], P = 0.0002, I(2) = 0%). Both subgroup analysis and network analysis demonstrated that both intravenous lidocaine (subgroup: RR = 0.39, 95% CI = [0.18, 0.86], P = 0.02, I(2) = 38%; network: RR = 0.25, 95% CI = [0.04, 0.86]) and topical lidocaine (subgroup: RR = 0.37, 95% CI = [0.19, 0.72], P = 0.003, I(2) = 0%; network: RR = 0.14, 95% CI = [0.02, 0.55]) was effective in laryngospasm prevention, while no statistical difference was found in a comparison between intravenous and topical lidocaine. In conclusion, both intravenous and topical lidocaine are effective in laryngospasm prevention in pediatric surgery, while a comparison between them needs more evidences.

Prevention of laryngospasm with rocuronium in cats: a dose-finding study.

OBJECTIVE: To identify the dose of rocuronium that will prevent a laryngeal response to water spraying of the glottis in anesthetized cats. STUDY DESIGN: Randomized crossover study. ANIMALS: Eight healthy, adult, short-haired cats, aged 1-4 years, weighing 3.2-6.0 kg. METHODS: Each cat was anesthetized four times and administered one of four doses of rocuronium (0.1, 0.2, 0.3 and 0.6 mg kg(-1) ) in random order. The larynx was observed with a video-endoscope inserted through a laryngeal mask airway. Video-clips of the laryngeal response to a sterile water spray (0.2 mL) were obtained at baseline (without rocuronium) and at maximal effect of each treatment. Glottal closure score (0-2), duration of glottal closure, and number of adductive arytenoid movements were obtained from video-clips of laryngeal responses (reproduced in slow motion) at baseline and after treatment. Two observers blinded to treatment allocation scored the vigor of the laryngeal response on a visual analog scale (VAS). The duration of apnea (up to 5 minutes) was recorded for each treatment. RESULTS: Compared with baseline, rocuronium 0.3 mg kg(-1) and 0.6 mg kg(-1) significantly decreased all glottal scores obtained from the videos (all p < 0.03). Both observers gave lower VAS scores after 0.3 mg kg(-1) (both p = 0.015). Apnea lasting ≥ 5 minutes occurred in none, one, three and seven of eight cats administered doses of rocuronium 0.1, 0.2, 0.3 and 0.6 mg kg(-1) , respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Rocuronium 0.3 mg kg(-1) and 0.6 mg kg(-1) consistently decreased the completeness and duration of the laryngeal response to water spray, and reduced the number of arytenoid adductive movements in response to that stimulus. However, a laryngeal response was never completely prevented. Rocuronium 0.3 mg kg(-1) may be useful for facilitating tracheal intubation. Positive pressure ventilation must be available for cats administered rocuronium.

Guideline for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures: Update 2016.

The safe sedation of children for procedures requires a systematic approach that includes the following: no administration of sedating medication without the safety net of medical/dental supervision, careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications, appropriate fasting for elective procedures and a balance between the depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure, a focused airway examination for large (kissing) tonsils or anatomic airway abnormalities that might increase thepotential for airway obstruction, a clear understanding of the medication's pharmacokinetic and pharmacodynamic effects and drug interactions, appropriate training and skills in airway management to allow rescue of the patient, age- and size-appropriate equipment for airway management and venous access, appropriate medications and reversal agents, sufficient numbers of staff to both carry out the procedure and monitor the patient, appropriate physiologic monitoring during and after the procedure, a properly equipped and staffed recovery area, recovery to the presedation level of consciousness before discharge from medical/dental supervision, and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatric providers updated information and guidance in delivering safe sedation to children.

Effect of gantacurium on evoked laryngospasm and duration of apnea in anesthetized healthy cats.

OBJECTIVE: To evaluate whether the ultrashort-acting neuromuscular blocking agent gantacurium can be used to blunt evoked laryngospasm in anesthetized cats and to determine the duration of apnea without hemoglobin desaturation. ANIMALS: 8 healthy adult domestic shorthair cats. PROCEDURES: Each cat was anesthetized with dexmedetomidine and propofol, instrumented with a laryngeal mask, and allowed to breathe spontaneously (fraction of inspired oxygen, 1.0). The larynx was stimulated by spraying sterile water (0.3 mL) at the rima glottidis; a fiberscope placed in the laryngeal mask airway was used to detect evoked laryngospasm. Laryngeal stimulation was performed at baseline; after IV administration of gantacurium at doses of 0.1, 0.3, and 0.5 mg/kg; and after the effects of the last dose of gantacurium had terminated. Duration of apnea and hemoglobin oxygen saturation (measured by means of pulse oximetry) after each laryngeal stimulation were recorded. Neuromuscular block was monitored throughout the experiment by means of acceleromyography on a pelvic limb. RESULTS: Laryngospasm was elicited in all cats at baseline, after administration of 0.1mg of gantacurium/kg, and after the effects of the last dose of gantacurium had terminated. The 0.3 and 0.5 mg/kg doses of gantacurium abolished laryngospasm in 3 and 8 cats, respectively, and induced complete neuromuscular block measured at the pelvic limb; the mean ± SE duration of apnea was 2 ± 1 minutes and 3 ± 1.5 minutes, respectively. Hemoglobin oxygen saturation did not decrease significantly after administration of any dose of gantacurium. CONCLUSIONS AND CLINICAL RELEVANCE: Gantacurium may reduce tracheal intubation-associated morbidity in cats breathing oxygen.