Is there a correlation between right bronchus length and diameter with age?

Measurement of the lengths of different sections of the upper airway and their predictive factors

BACKGROUND

No studies have been conducted to define the lengths of the upper airway's different segments in normal healthy adults.

AIMS/OBJECTIVES

This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it.

MATERIAL AND METHODS

This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway.

RESULTS

The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm.

CONCLUSION AND SIGNIFICANCE

We concluded that a normal healthy adult's anterior subglottis length is 6.3-19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1-20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2-98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length.

Changes in tapered endotracheal tube cuff pressure after changing position to hyperextension of neck: A randomized clinical trial

BACKGROUND

Endotracheal tube (ETT) with a tapered-shaped cuff had an improved sealing effect when compared to ETTs with a conventional cylindrical-shaped cuff. Positional change and neck movement typically displace an ETT and change the intracuff pressure. The aim of the current study was to compare the ETT cuff pressure in the TaperGuard ETT vs the conventional ETT after a change from the supine, neutral position to the extension of the neck and semi-Fowler position for thyroid surgery.

METHODS

This prospective, randomized clinical trial included 50 patients undergoing thyroidectomy. Patients were randomly allocated into one of the 2 groups: tracheal intubation with the TaperGuard ETT or with a conventional ETT. The ETT cuff was inflated with air and the ETT cuff pressure was set initially at 20 cmH2O using a calibrated cuff manometer. ETT cuff pressure and distance from carina to ETT tip were measured at supine and semi-Fowler positions with neck extension.

RESULTS

After the position change, the ETT tip migrated cephalad and cuff pressure increased in the majority of cases. ETT cuff pressure was significantly higher in the TaperGuard group than the conventional group (28.0 ± 6.6 cmH2O and 22.8 ± 4.5 cmH2O, respectively, P = .001). The degree of cephalad displacement of the ETT tip was comparable between the 2 groups (19.4 ± 6.31 mm in TaperGuard group and 21.9 ± 6.9 mm in conventional group, P = .12).

CONCLUSIONS

After the position change from supine to hyperextension of the neck, the ETT cuff pressure was higher in the TaperGuard ETT than in the conventional ETT, although the extent of displacement of the ETT was comparable between the 2 groups.

The lengths of trachea and main bronchus in Chinese Shanghai population

The knowledge of airway length is the theoretical basis in the diagnosis and management of airway disease. The objective of this study is to measure the length of trachea and left and right main bronchus in Chinese Shanghai population. A total of 153 consecutive adult patients with minor pulmonary disease in Xinhua hospital were enrolled for bronchoscopy examination. Measurements were conducted on head and neck neutral position and height, weight and age for each patient were recorded either. Student t test and multiple linear regression was used to compare means between males and females and to analyze correlation among height, weight, sexual dimorphism and the lengths of the trachea and bronchus. The lengths of the trachea and left main bronchus are significantly different between male and female patients (P < 0.01), but not for the lengths of right main bronchus between man and woman. Multiple linear regression analysis showed that height but not sexual dimorphism and weight correlated with the lengths of the trachea and right main bronchus. The lengths of the trachea and left main bronchus are significantly longer in males than in females. Moreover, height but not sexual dimorphism and weight influenced the length of airway.

What is the Adequate Cuff Volume for Tracheostomy Tube? A Pilot Cadaver Study

OBJECTIVE

To determine the patterns of tracheostomy cuff pressure changes with various air inflation amounts in different types of tracheostomy tubes to obtain basic data for appropriately managing long-term tracheostomy.

METHODS

We performed tracheostomy on a 46-year-old male cadaver. Three types of tracheostomy tubes (single-cuffed, double-cuffed, and adjustable flange), divided into 8 different subtypes based on internal tube diameters and cuff diameters, were inserted into the cadaver. Air was inflated into the cuff, and starting with 1 mL air, the cuff pressure was subsequently measured using a manometer.

RESULTS

For the 7.5 mm/14 mm tracheostomy tube, cuff inflation with 3 mL of air yielded a cuff pressure within the recommended range of 20-30 cmH2O. The 7.5 mm/24 mm tracheostomy tube showed adequate cuff pressure at 5 mL of air inflation. Similar values were observed for the 8.0 mm/16 mm and 8.0 mm/27 mm tubes. Double-cuffed tracheostomy cuff pressures (7.5 mm/20 mm and 8.0 mm/20 mm tubes) at 3 mL air inflation had cuff pressures of 18-20 cmH2O at both the proximal and distal sites. For the adjustable flange tracheostomy tube, cuff pressure at 6 mL of cuff air inflation was within the recommended range. Maximal cuff pressure was achieved at inflation with almost 14 mL of air, unlike other tube types.

CONCLUSION

Various types of tracheostomy tubes showed different cuff pressures after inflation. These values might aid in developing guidelines For patients who undergo tracheostomy and are discharged home without cuff pressure manometers, this standard might be helpful to develop guidelines.

Comparison of the cuff pressure of a TaperGuard endotracheal tube and a cylindrical endotracheal tube after lateral rotation of head during middle ear surgery: A single-blind, randomized clinical consort study

BACKGROUND

Positional change affects the cuff pressure of an endotracheal tube (ETT) in treacheally intubated patients. We compared the cuff pressure of a TaperGuard ETT and a cylindrical ETT after lateral rotation of head during middle ear surgery.

METHODS

Fifty-two patients aged 18-70 years underwent a tympanomastoidectomy under general anesthesia were randomly allocated to receive endotracheal intubation with cylindrical (group C, n = 26) or TaperGuard ETTs (group T, n = 26). After endotracheal intubation, the ETT cuff pressure was set at 22 cmH2O in the neutral position of head. After lateral rotation of head, the cuff pressure was measured again and readjusted to 22 cmH2O. In addition, the change of distance from the carina to the tip of the ETT was measured before and after the positional change. The incidence of cough, sore throat, and hoarseness was assessed at 30 minutes, 6 hours, and 24 hours after surgery.

RESULTS

There was no difference in demographic data between groups. After lateral rotation of head, the cuff pressure significantly increased in group T (11.9 ± 2.3 cmH2O) compared with group C (6.0 ± 1.9 cmH2O) (P < 0.001). The incidence of a cuff pressure >30 cmH2O was higher in group T (96.2%) than in group C (30.8%) (P < 0.001). In addition, the degree of displacement of an ETT was greater in group T (11.0 ± 1.7 mm) than in group C (7.2 ± 2.6 mm) (P < 0.001). The overall incidences of postoperative sore throat, hoarseness, and cough at 30 minutes, 6 hours, and 24 hours after surgery were comparable between two groups.

CONCLUSION

The cuff pressure was higher in the TaperGuard ETT than in the cylindrical ETT after positional change of head from neutral to lateral rotation. In addition, after a positional change, the extent of displacement of ETT was greater in the TaperGuard ETT than in the cylindrical ETT.

Anatomy and physiology of respiratory system relevant to anaesthesia

Clinical application of anatomical and physiological knowledge of respiratory system improves patient's safety during anaesthesia. It also optimises patient's ventilatory condition and airway patency. Such knowledge has influence on airway management, lung isolation during anaesthesia, management of cases with respiratory disorders, respiratory endoluminal procedures and optimising ventilator strategies in the perioperative period. Understanding of ventilation, perfusion and their relation with each other is important for understanding respiratory physiology. Ventilation to perfusion ratio alters with anaesthesia, body position and with one-lung anaesthesia. Hypoxic pulmonary vasoconstriction, an important safety mechanism, is inhibited by majority of the anaesthetic drugs. Ventilation perfusion mismatch leads to reduced arterial oxygen concentration mainly because of early closure of airway, thus leading to decreased ventilation and atelectasis during anaesthesia. Various anaesthetic drugs alter neuronal control of the breathing and bronchomotor tone.