Tracheal intubation: optimal conditions, vocal cord damage, and allergy

[Clinical outcomes of vocal fold immobility after tracheal intubation]

OBJECTIVE

To assess the incidence of postoperative vocal cord immobility in patients following endotracheal intubation underwent general anesthesia.

METHODS

We retrospectively enrolled patients who underwent surgical procedures with endotracheal intubation under general anesthesia from January 2014 to December 2018 in Peking University First Hospital. Demographic and treatment data were obtained for patients with hoarseness and vocal cord fixation. The incidence of postoperative hoarseness and vocal cord fixation were presented and clinical outcomes were further analyzed.

RESULTS

A total of 85 998 patients following tracheal intubation and general anesthesia were enrolled in this study. Hoarseness was observed in 222 (0.26%) patients postoperatively. Sixteen patients (73%) were accomplished with symptoms of choking on water, dysphonia and sore throat. Twenty-nine patients with persistent hoarseness on the third postoperative day needed further treatment by otolaryngologists. Among them, seven patients had pharyngolaryngitis and twenty-two patients (0.026%) were demonstrated postoperative vocal cord immobility. There were seventeen patients (77%) with left-side vocal cord fixation and five patients (23%) with right-side vocal cord fixation. Nine patients were identified with arytenoid dislocation. Seven patients had left vocal cord fixation and two patients had right-side vocal cord fixation. Seven patients were intubated under the guidance of visual laryngoscope. One patient was confirmed difficult airway and intubated with light wand. One patient was inserted with laryngeal mask airway. One patient was suspected to have hoarseness caused by gastric tube before anesthesia. One patient showed simultaneously left recurrent laryngeal nerve abnormality on laryngeal electromyography result. The symptom of hoarseness ranged between 6 and 31 days. Three patients underwent closed reduction under local anesthesia and one patient demonstrated spontaneous recovery. Among the remaining thirteen patients with vocal cord immobility, two patients were demonstrated vocal cord paralysis. Eleven patients underwent neck surgery, thyroid surgery and cardiothoracic surgery and further examinations including laryn-geal electromyography and computed tomography help to determine the diagnosis were not performed. All patients were treated with inhaled corticosteroid conservatively. Five patients had significant improvement of symptom and almost regained normal voice. One patient had slight improvement and sixteen patients were not relieved before discharge.

CONCLUSION

Patients with hoarseness and vocal fold immobility after endotracheal intubation should be treated properly and immediately.

A closed claims analysis of vocal cord injuries related to endotracheal intubation between 2004 and 2015

STUDY OBJECTIVE

To provide a contemporary medicolegal analysis of claims brought against anesthesiologists for injuries related to endotracheal intubation.

DESIGN

A retrospective study of closed claims data from the Controlled Risk Insurance Company (CRICO) Comparative Benchmarking System (CBS) database between 2004 and 2015.

SETTING

Closed claims that occurred in any surgical specialty in which the patient was undergoing general anesthesia and anesthesiology was named as the primary responsible service.

PATIENTS

Twenty claims were identified for analysis in 7 surgical specialties. Patient ages ranged from 45 to 76. Data regarding patient comorbidities and case history were obtained when available.

INTERVENTIONS

None.

MEASUREMENTS

Data collected includes patient demographics such as age, outcome severity, alleged complication, plaintiff allegations, contributing factors to the injury, the surgical specialty in which the injury occurred, and the ultimate result of the claim (dismissed/denied/settled).

MAIN RESULTS

Out of 20 claims, settlement payments were made in 10% of claims with a mean payment amount of $7669. Mean patient age was 55.6 years. Within severity of injuries, 65% of claims were classified as "Permanent Minor." The most common contributing factor in claims was "Technical Knowledge/Performance" and the most common plaintiff allegation was "Trauma from endotracheal tube placement." Bilateral vocal cord paralysis, unilateral (left-sided) vocal cord paralysis, and laryngeal nerve injury were the top alleged complications. The surgical specialty in which claims most often resulted was orthopedic surgery.

CONCLUSIONS

Injuries related to endotracheal intubation remain an ongoing challenge to anesthesiologists. Their etiology is often multifactorial and was found in this study to stem most commonly from technical errors and patient co-morbidities. A detailed discussion of risks with patients during the consent process, careful documentation of such discussion, and prompt referral to specialists when needed are critical. Understanding the patterns related to injuries during intubation is essential in order to develop strategies for improved patient safety and outcomes.

Laryngeal morbidity after tracheal intubation: the Endoflex(®) tube compared to conventional endotracheal intubation with stylet

BACKGROUND

Tracheal intubation may cause vocal fold damage. The trial was designed to assess laryngeal morbidity comparing the Endoflex(®) tube with a conventional endotracheal tube with stylet. We hypothesised that laryngeal morbidity within the first 24 h after extubation would be lower with the Endoflex tube than with the conventional endotracheal tube with stylet because of less rigidity.

METHODS

This randomised trial included 130 elective surgical patients scheduled for general anaesthesia with endotracheal intubation. Pre- and post-operative assessment of hoarseness, vocal fold pathology, and voice analysis using the Multidimensional Voice Program was performed. Induction of anaesthesia was standardised. After complete neuromuscular paralysis, intubation was done with an Endoflex tube or a conventional endotracheal tube with stylet.

RESULTS

Post-operative hoarseness was found in 45% with the Endoflex tube and 55% with the endotracheal tube with stylet at 24 h after extubation (P = 0.44). Post-operative vocal fold injury was present in 23% in the Endoflex tube group and in 36% in the endotracheal tube with stylet group (P = 0.13). The increase in shimmer, the voice analysis variable reflecting vocal fold oedema, was 0.5% in the Endoflex tube group and 2.5% in the endotracheal tube with stylet group (P = 0.02).

CONCLUSION

No significant difference was found in the incidence of hoarseness or vocal fold injury using the Endoflex tube. However, the statistically significant lower increase in the shimmer values in that group implies that the Endoflex may be associated with less laryngeal morbidity.

Magnesium sulphate: an adjuvant to tracheal intubation without muscle relaxation--a randomised study

CONTEXT

Tracheal intubation without administration of a neuromuscular blocking drug is used frequently in anaesthesia. Several techniques and adjuvants have been tried to improve intubating conditions. Magnesium sulphate is an agent with analgesic, anaesthetic and muscle relaxant effects.

OBJECTIVE

To assess the effect of magnesium sulphate on intubating conditions after induction of anaesthesia without a neuromuscular blocking drug.

DESIGN

Double-blinded randomised study.

PATIENTS

Sixty patients with American Society of Anesthesiologists physical status 1/2 scheduled for elective surgery under general anaesthesia were included.

SETTING

Avicenna Military Hospital between June 2010 and March 2011.

INTERVENTIONS

Before induction of general anaesthesia, patients were assigned to receive either a 10-min infusion of magnesium sulphate 45 mg kg(-1) in 100 ml of isotonic saline (magnesium group, n = 30) or the same volume of saline (control group, n = 30). Anaesthesia was induced with fentanyl 3 μg kg(-1) followed 3 min later by propofol 2.5 mg kg(-1).

MAIN OUTCOME MEASURES

Intubating conditions were evaluated by a blinded anaesthesiologist using the criteria of the Copenhagen consensus conference: ease of laryngoscopy, vocal cord position and/or movement and response to intubation or cuff inflation (cough or diaphragmatic movement). Intubating conditions were considered as acceptable (excellent or good) or unacceptable (poor). Mean arterial pressure and heart rate were also recorded during the study period.

RESULTS

The two groups were comparable in their demographic profiles. Clinically acceptable intubating conditions were observed more frequently in the magnesium group than in the control group: 25 (83%) vs. 18 patients (60%) (P = 0.042). There was no failed intubation. There were no differences between the groups with regard to haemodynamic variables.

CONCLUSION

Addition of magnesium sulphate to propofol and fentanyl at induction of anaesthesia significantly improved intubating conditions without administration of a neuromuscular blocking drug.

The optimal dose of remifentanil for acceptable intubating conditions during propofol induction without neuromuscular blockade

STUDY OBJECTIVE

To determine the optimal remifentanil dose required to provide acceptable intubating conditions following induction of anesthesia with propofol without using neuromuscular blockade.

DESIGN

Dose-response study.

SETTING

Operating room of a university hospital.

PATIENTS

50 ASA physical status 1 men, aged between 20 and 40 years, who were scheduled for general anesthesia.

INTERVENTIONS

Intubating conditions were evaluated according to the scoring system described by Viby-Mogensen et al. Successful intubation was defined as excellent or good.

MEASUREMENTS

For induction of anesthesia, an intravenous (IV) bolus dose of propofol 2.0 mg/kg was given over 30 seconds followed by the administration of predetermined IV remifentanil over 30 seconds; intubation was performed 90 seconds after completion of the remifentanil administration. The dose of remifentanil used for each patient was determined by the response of the previously tested patients, using the modified Dixon's up-and-down method (using 0.2 μg/kg as a step size). The first patient was tested with remifentanil 1.0 μg/kg. If intubation failed, the remifentanil dose was increased by 0.2 μg/kg; if intubation was successful, the dose was decreased by 0.2 μg/kg. Mean arterial pressure (MAP), heart rate (HR), and peripheral oxygen saturation were recorded during the study period.

MAIN RESULTS

According to probit analysis, the effective dose of remifentanil in 50% (ED(50)) and 95% (ED(95)) of patients were 1.40 μg/kg and 2.40 μg/kg, respectively. Preintubation and postinduction HR and MAP values were lower than preinduction values (P < 0.001).

CONCLUSION

The optimal bolus dose of remifentanil for acceptable intubating conditions was 2.40 μg/kg (95% confidence interval, 1.90-9.0 μg/kg) in 95% of patients during induction of anesthesia with propofol 2.0 mg/kg without neuromuscular blocking agents.