Characteristics of lower airway parameters in an adult Asian population related to endotracheal tube design: a cadaveric study

The risk of endotracheal tube (ETT) placement includes endobronchial intubation and subglottic injury. This study aimed to describe the lengths of lower airway parameters related to cuff location and vocal cord markings in different adult-sized ETTs. Eighty cadavers were examined for the lengths of the lower airway, including their correlations and linear regressions with height. Thirty adult-sized ETTs from seven different brands were examined for Mark-Cuff and Mark-Tip distances. The depth of ETT placement was simulated for each brand using vocal cord marking. The mean (standard deviation) lengths from the subglottis, trachea, vocal cord to mid- trachea, and vocal cord to carina were 24.2 (3.5), 97.9 (8.6), 73.2 (5.3), and 122.1 (9.0) mm, respectively. Airway lengths were estimated as: (1) subglottis (mm) = 0.173 * (height in cm) - 3.547; (2) vocal cord to mid-trachea (mm) = 0.28 * (height in cm) + 28.391. There were variations in the Mark-Cuff and Mark-Tip distances among different ETTs. In the simulation, endobronchial intubation ranged between 2.5 and 5% and the cuff in the subglottis ranged between 2.5 and 97.5%. In summary, the lower airway parameters were height-related. ETT placement using vocal cord marking puts the patient at a high risk of cuff placement in the subglottis.

A Study of Morphological Characteristics of Lung Fissures and Trachea in the Indian Population

Tracheal length and lung anatomy have been rarely studied; however, the anatomy of the lung has been shown to vary significantly. Moreover, the surgery regarding trachea are few, and hence the surgeons do not have extensive experience in the trachea.

Objective: We aimed to study the variations of the lung anatomy and the relation between tracheal length and body height in the Indian population.

Materials and methods: This is an observational study to observe the tracheal length in relation to body height and sex and gross morphological anatomy of the lung in 70 cadavers. The data was collected from the forensic department of Bangalore Medical College and Research Institute (BMCRI), and further analysis was done at Kidwai Memorial Institute of Oncology.

Results: Deviation from normal lung morphology was seen in 37.86% of the specimens studied. The tracheal length (average, 9.97 cm) correlated with the body length (average, 147.02 cm) with a Pearson coefficient of 0.806 (p value=0.001)

Conclusion: The study of lung fissure morphology guides clinicians in understanding and planning lung disease treatment, especially lobectomy/segmentectomy surgeries. The information of the average length of the trachea with respect to body height in a given ethnicity will help during endotracheal intubation and tracheal surgical planning.

Superficial placement of endotracheal tubes associated with unplanned extubation: A case-control study

INTRODUCTION

Unplanned extubations (UEs) refer to the inadvertent removal of endotracheal tubes (ETTs). Superficially placed ETTs anecdotally increases the risk of UEs. This study aims to assess the impact of ETT position as well as other factors that could be associated with risk of UEs.

METHOD

A retrospective case-control study was conducted at NewYork-Presbyterian Queens Hospital from January 2017 to February 2020. All adults admitted to intensive care units (ICUs) who received mechanical ventilation (MV) through ETTs were screened to identify UEs. For each case with UE, two controls with planned extubation were identified. A multivariate logistic regression was conducted to identify risk factors associated with UEs.

RESULTS

1100 patients received MV through ETTs during the time period. The incidence of UE was 4.9%. 53 patients with UEs and 106 patients with planned extubation were included for statistical analysis. Overall, patients with UE had higher in-hospital mortality rates (26.4% versus 11.3%, P = 0.02) and reintubation rates (28.3% versus 6.6%, P < 0.001). Within the UE group, patients who required reintubation had significantly higher in-hospital mortality rates than those who did not require reintubation (53.3% versus 15.8%, P = 0.005). Multivariate logistic regression showed higher APACHE II scores (Odds ratios (OR) 1.07; 95% Confidence interval (CI), 1 to 1.13), distance of ETT tips to carina ≥6 cm (OR 6.41; 95% CI, 1.1 to 37.3), physical restraint use (OR 2.98; 95% CI, 1.28 to 6.95) and continuous infusions of sedatives and/or analgesics (OR 10.72, 95% CI, 4.19 to 27.43) were associated with UE.

CONCLUSION

UE and the need for reintubation is associated with worse outcomes. Distance of ETT tips to carina ≥6 cm may be associated with higher risks of UE. Further prospective studies are needed to establish the optimal position of ETT to prevent UE.

Intraoperative Airway Management Considerations for Adult Patients Presenting With Tracheostomy: A Narrative Review

Tracheotomy is a surgical procedure through which a tracheostomy, an opening into the trachea, is created. Indications for tracheostomy include facilitation of airway management during prolonged mechanical ventilation, treatment of acute upper airway obstruction when tracheal intubation is unfeasible, management of chronic upper airway obstructive conditions, and planned airway management for major head and neck surgery. Patients who have a recent or long-term tracheostomy may present for a variety of surgical or diagnostic procedures performed under general anesthesia or sedation/analgesia. Airway management of these patients can be challenging and should be planned ahead of time. Anesthesia personnel should be familiar with the different components of cuffed and uncuffed tracheostomy devices and their connectivity to the anesthesia circuits. An appropriate airway management plan should take into account the indication of the tracheostomy, the maturity status of the stoma, the type and size of tracheostomy tube, the expected patient positioning, and presence of patient's concurrent health conditions. Management of the patient with a T-tube is highlighted. Importantly, there is a need for multidisciplinary care involving anesthesiologists, surgical specialists, and perioperative nurses. The aim of this narrative review is to discuss the anesthesia care of patients with a tracheostomy. Key aspects on relevant tracheal anatomy, tracheostomy tubes/devices, alternatives of airway management, and possible complications related to tracheostomy are summarized with a recommendation for an algorithm to manage intraoperative tracheostomy tube dislodgement.

An observational study to determine whether alignment of endotracheal tube indicator line with the vocal cords results in appropriate depth of intubation

Background: Inappropriate endotracheal tube placement depth may be associated with complications. Objective: To determine whether the accurate alignment of the indicator ring on the endotracheal tube at the level of the vocal cords, results in its appropriate placement. Design: Prospective observational study. Patients: 98 adult patients scheduled for general anesthesia with orotracheal intubation. Interventions: The indicator band mark on the endotracheal tube was accurately placed at the vocal cords level under video-laryngoscope view. The tube length at the right upper incisor and the distance between its tip and the carina was measured using fibreoptic bronchoscope. Data to validate methods to predict insertion depth was collected and evaluated. Main Outcome: To determine the distance between the tip of the endotracheal tube and the carina. Results: The endotracheal tube tip depth was inap- propriate in 46.94% cases and was <3 cm above the carina in 41.64% cases. This difference in this distance was similar (p = 0.246) in the two genders. A correlation was noted between topographic length and insertion depth in females only (r2 = 0.201 and p = 0.001). The mean tracheal length was 12.66 + 1.35 cm in males and 12.04 + 1.26 cm in females. Conclusion: We found a high incidence of endo- tracheal tube tip malposition despite the accurate placement of the indicator band at the vocal cords level. We suggest that international endotracheal tube design standards be defined and endotracheal tube manufacturers modify the standard intratracheal length.

Clinical Implications of Vocal Cord-Carina Distance and Tracheal Length in the Indian Population

Objective

Securing the tracheal tube (TT) at a fixed recommended depth of 21/23 cm in female and male patients, respectively, may result in inappropriate placement of the TT in some patients. The aim of the present study was to determine the vocal cord-carina distance (VCD) and tracheal length (TL) to ascertain the optimal depth of TT placement during orotracheal intubation in the adult Indian population.

Methods

A total of 92 adults undergoing elective surgery under general anaesthesia with orotracheal intubation were studied. Surface anatomy airway measurements were noted. A cuffed TT (female size 7 mm ID and male size 8 mm ID) was inserted with the intubation guide mark at level with the vocal cords (VCs). Fiberoptic bronchoscopy-guided measurements were obtained for VCD, TL, TT tip-carina distance, VC-cricoid distance and lip-carina (L-C) distance.

Results

The mean±SD VCD was 12.82±2.05 and 12.02±1.44 cm, and TL was 10.14±2.04 and 9.37±1.28 cm in male and female patients, respectively. Statistically significant differences were observed between male and female patients in VCD (p=0.033), TL (p=0.032), L-C distance (p<0.001) and lip-TT tip distance (p<0.001); lip-TT tip distance was 19.50±1.39 cm in male patients and 18.17±1.28 cm in female patients. The L-C distance correlated with patient height, weight and neck length. L-C distance=7.214+0.049×Height+0.320×Neck length+0.033×Weight.

Conclusion

We recommend placing the TT with its proximal guide mark at the level of VCs in the Indian population. The 21/23 cm rule for tube placement depth in female and male patients, respectively, cannot be routinely followed in the Indian population.

A multi-center evaluation of a disposable catheter to aid in correct positioning of the endotracheal tube after intubation in critically ill patients

PURPOSE

To demonstrate that use of a minimally invasive catheter reduces endotracheal tube (ETT) malposition rate after intubation.

MATERIALS AND METHODS

This study is a multi-center, prospective observational cohort of intubated patients in the medical intensive care unit. The catheter was inserted into the ETT immediately after intubation. The ETT was adjusted accordingly based on qualitative color markers on the catheter. A confirmatory chest radiograph was obtained to determine the ETT position. Malposition of the ETT was defined by the distal ETT not being within 2-5 cm above the carina.

RESULTS

Sixty-nine patients were enrolled, age 56.2 ± 19.5 years, body mass index 31.0 ± 13.8 kg/m². The catheter prompted repositioning of the ETT in 39 (56.5%) patients. Using the catheter, the rate of malposition decreased to 7.2%, with the distal ETT position at 3.7 ± 1.2 cm above the carina. Without the catheter, the ETT malposition rate would have been 39.1%. The time for catheter use and chest radiograph completion at our institutions was 1.7 ± 1.5 and 44.4 ± 36.4 min, respectively.

CONCLUSIONS

With use of an ETT positioning catheter after intubation, the ETT malposition rate was reduced by 82%. This catheter-based system was safe, and its use may perhaps decrease the need for the post-intubation chest radiograph.

Otolaryngology in Critical Care

Diseases affecting the ear, nose, and throat are prevalent in intensive care settings and often require combined medical and surgical management. Upper airway occlusion can occur as a result of malignant tumor growth, allergic reactions, and bleeding events and may require close monitoring and interventions by intensivists, sometimes necessitating surgical management. With the increased prevalence of immunocompromised patients, aggressive infections of the head and neck likewise require prompt recognition and treatment. In addition, procedure-specific complications of major otolaryngologic procedures can be highly morbid, necessitating vigilant postoperative monitoring. For optimal outcomes, intensivists need a broad understanding of the pathophysiology and management of life-threatening otolaryngologic disease.

Assessment of the reliability of intubation and ease of use of the Cook Staged Extubation Set-an observational study

The Staged Extubation Set has recently been introduced by Cook Medical for the management of difficult airway patients who potentially require reintubation; however, its reliability for intubation and ease of use is not reported in the literature. The set contains a wire and reintubation catheter with a central lumen for the wire and oxygenation if required. Reintubation is by a two-stage Seldinger-like technique. After induction of general anaesthesia, 23 low-risk elective surgical patients had the Staged Extubation Wire from the Cook set inserted into their trachea under direct laryngoscopy. The intubation was subsequently completed using the rest of the Staged Extubation Set as designed. Difficult intubation was simulated by intentionally decreasing the laryngeal view. Simulated reintubation failed in 8.3% and significant technical difficulty in simulated reintubation was noted in another 17.3% of intubation sequences. The latter represent probable failures in a clinical difficult reintubation setting. The mean time taken to intubate was 109 seconds. Using the Cook Staged Extubation Set may be inferior to using an airway exchange catheter for reintubation.

The Tracheal Accordion and the Position of the Endotracheal Tube

The purpose of this review is to, first, determine the static factors that affect the length of the human trachea across different populations and, second, to investigate whether or not there are dynamic factors that cause the length of the human trachea to vary within the same individual. We also investigated whether these changes in tracheal length within the same individual are significant enough to increase the risk of endobronchial intubation or accidental extubation. A PubMed/MEDLINE and a Web of Science database English-language literature search was conducted in May 2016 with relevant keywords and MeSH terms when available. We found that gender, extremes of age, patient height, postsurgical changes and co-existing disease are static patient factors that affect the length of the human trachea. Dynamic clinical changes that occur under anaesthesia, including Trendelenburg position, head and neck flexion and extension, paralysis of the diaphragm and pneumoperitoneum, cause the trachea to act as an accordion, decreasing and increasing its length. The length of the human trachea in both awake and anaesthetised and paralysed patients is a critical consideration in preventing both endobronchial intubation and tracheal extubation. It is clear from the literature that tracheal length varies widely across populations and, additionally, with the dynamic clinical changes that occur under anaesthesia, the trachea acts as an accordion decreasing and increasing its length within the same individual. Knowledge of the magnitude of the change in tracheal dimensions in response to these factors is an important clinical consideration.

Inadvertent Endobronchial Intubation in a Patient With a Short Neck Length

Inadvertent placement of the endotracheal tube into the right bronchus during intubation for general anesthesia is a fairly common occurrence. Many precautions should be taken by the anesthesia provider in order to minimize the incidence of endobronchial intubation, including bilateral auscultation of the lungs, use of the 21/23 rule, and palpation of the inflated endotracheal cuff at the sternal notch. These provisions, however, are not foolproof; anesthesia providers should realize that endobronchial intubation may occur from time to time because of variations in patient anatomy, changes in patient positioning, and cephalad pressures exerted during surgery. A 58-year-old man with chronic obstructive pulmonary disease received general endotracheal anesthesia for a laparoscopic cholecystectomy. His height was 165 cm (5 ft, 5 in) and the endotracheal tube was secured at his incisors at 21 cm after placement with a rigid laryngoscope. Bilateral breath sounds were confirmed with auscultation, although they were distant because of his chronic obstructive pulmonary disease. After radiographic examination in the postanesthesia care unit, a right main-stem intubation was revealed to have taken place, resulting in complete atelectasis of the left lung. After repositioning of the endotracheal tube, radiography confirmed that the patient had an anatomically short tracheal length.