Tracheal shortening during laparoscopic gynecologic surgery

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.

Positional relationships between a tracheal diverticulum and the tracheal tube under general anesthesia: a single-center observational and simulation study

BACKGROUND

Incomplete sealing of tracheal diverticula by a tracheal tube cuff during positive-pressure ventilation causes barotrauma but the concrete possibility of incomplete sealing has not been indicated. We aimed to assess the possibility of incomplete sealing in a simulated situation of tracheal intubation for patients with tracheal diverticula with tube fixation where the tracheal tube's vocal cord guide overlaps with the patient's vocal cord.

METHODS

We retrospectively assessed the characteristics of tracheal diverticula based on thoracic computed tomography data in our institution from January 2018 to July 2020. Then, we assessed the structural parameters of three single-lumen tracheal tubes (Parker Flex-Tip [Parker Medical, Bridgewater, CT, USA], Portex Soft Seal [ICU Medical, San Clemente, CA, USA], and Shiley TaperGuard [Medtronic, Dublin, Ireland]; 6.0-8.0 mm inner diameter size) and simulated the positional relationships between tracheal diverticula and the tracheal tube during tracheal intubation where the vocal cord guide overlaps with the patient's vocal cord. We assessed each tube product's possibility of incompletely sealing tracheal diverticula and the possibility of unintended bronchial intubation.

RESULTS

In 5,854 patients, the prevalence of tracheal diverticula was 5.7%. The mean (SD) length from the vocal cord to the distal end of the tracheal diverticula was 52.2 (12.8) mm. Tracheal tubes with length from the distal end of the tracheal cuff to the vocal cord guide of ≥ 70 mm had a low risk of incompletely sealing tracheal diverticula (< 5%) and length from the distal end of the tube to the vocal cord guide of ≤ 95 mm had a low risk of unintended bronchial intubation (< 5%). No products in this study satisfied both outcomes.

CONCLUSIONS

Tube fixation, where the vocal cord guide overlaps with the patient's vocal cord, is associated with risk of incompletely sealing of tracheal diverticula depending on the tube's manufacturer and tube's inner diameter size, although it was not a high risk. The use of small inner diameter sized tube relative to patient's body size is high risk of incomplete sealing of tracheal diverticula.

TRIAL REGISTRATION

This trial was prospectively registered at University Hospital Medical Information Network (UMIN).

CLINICAL TRIAL NUMBER AND REGISTRY URL

UMIN000043317 (URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000048055 ).

Endotracheal Tube Migration in Steep Trendelenburg Position With the Estape TrenMAX Positioning System

The extent of endotracheal tube (ETT) migration was studied in 25 adult female patients undergoing robotic-assisted laparoscopic gynecologic surgery while in a steep Trendelenburg position secured with the Estape TrenMAX positioning system (Innovative Medical Products, Plainville, CT, USA). In four patients, the distance from the tip of the ETT to the carina did not change. In three patients, the distance from the tip of the ETT to the carina decreased by 1 centimeter (cm). In other patients, the distance from the tip of the ETT to the carina decreased by 0.2 to 0.5 cm. We concluded that the tip of the ETT moves closer to the carina in patients put in the extreme Trendelenburg position. These results were in alignment with the evidence base created by other researchers.

Methods of endotracheal tube placement in patients undergoing pelviscopic surgery

Accidental endobronchial intubation is reported frequently during laparoscopic gynaecological surgery. We performed a prospective randomised study to compare three different methods of endotracheal tube placement in terms of susceptibility of accidental endobronchial intubation in patients undergoing laparoscopic gynaecologic surgery.

The endotracheal tube was positioned by one of three methods: it was secured by palpating at the suprasternal notch while holding the pilot balloon (Group); by placing the 21 cm mark at the upper incisors (Group21cm); or by placing a guide mark, which was made on the surface of the tube 2 cm above the proximal end of the cuff, at the level of the vocal cords (GroupVC). The distance from the tip of endotracheal tube to the carina was measured with the patient in a neutral position (DTC0) and after the formation of pneumoperitoneum in the Trendelenburg position (DTC1).

Eighty-eight patients were enrolled. Pneumoperitoneum and Trendelenburg position caused inward movement of the endotracheal tube toward the carina in 99%. In each group, the mean value of DTC1 was significantly shorter than DTC0 (Group Cuff 3.0 ± 1.1 vs. 1.7 ± 1.0, Group21cm2.5 ± 0.8 vs. 1.1 ± 0.9, Groupvc 3.5 ± 0.7 vs. 2.3 ± 0.8, DTc0 vs. DTC1 respectively)(all P <0.01). Accidental endobronchial intubation occurred in 14%, with the lowest frequency in Groupvc (2.6 %, P <0.01) and the highest in Group21cm, although this was not significantly (P=0.09) different from GroupCuff (26.7% vs. 10.0%).

The incidence of endobronchial intubation was lowest in Groupvc but endobrochial intubation could not be avoided using any of these methods.

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.

Intraoperative Neurophysiological Monitoring of the Laryngeal Nerves During Anterior Neck Surgery: A Review

Contributions to the literature on intraoperative neuro monitoring (IONM) during endocrine and head and neck surgery have increased over recent years. Organizational support for neural monitoring during surgery is becoming evident and is increasingly recognized as an adjunct to visual nerve identification. A comprehensive understanding of the role of IONM for prevention of nerve injuries is critical to maximize safety during surgery of the anterior compartment of the neck. This review will explore the potential advantages of IONM to improve the outcomes among patients undergoing anterior neck surgery.

Changes in uncuffed endotracheal tube leak during laparoscopic inguinal herniorrhaphy in children

The present study was conducted to investigate changes in uncuffed endotracheal tube (ETT) leak during laparoscopic surgery. The study included 31 patients aged between 1 and 6 years scheduled for elective laparoscopic inguinal herniorrhaphy. Inspiratory and expiratory tidal volumes (TVi and TVe) were measured during mechanical ventilation, and ETT leak was calculated using the formula-ETT leak = (TVi - TVe)/TVi × 100 (%), assessed at the following time-points-5 min after the start of mechanical ventilation (T1, baseline), just before the start of surgery (T2), 5 min after the induction of pneumoperitoneum with 15° Trendelenburg tilt (T3), and at the end of surgery (T4). Additionally, leak pressure was assessed after successful tracheal intubation (T0, baseline) at T2, T3 and T4. Uncuffed ETT leak significantly decreased at T3 compared with T1 (baseline). Leak pressure significantly increased at T3 and T4 compared with T0 (baseline). Further studies are needed in order to determine whether the results are universal and associated with clinically significant outcomes.

Changes in the distance between carina and orotracheal tube during open or videolaparoscopic bariatric surgery

OBJECTIVE

To examine whether there are changes in the distance between the orotracheal tube and carina induced by orthostatic retractor placement or by pneumoperitoneum insufflation in obese patients undergoing gastroplasty.

METHODS

60 patients undergoing bariatric surgery by two techniques: open (G1) or videolaparoscopic (G2) gastroplasty were studied. After tracheal intubation, adequate ventilation of both hemitoraxes was confirmed by lung auscultation. The distance orotracheal tube-carina was estimated with the use of a fiber bronchoscope before and after installation of orthostatic retractors in G1 or before and after insufflation of pneumoperitoneum in patients in G2.

RESULTS

G1 was composed of 22 and G2 of 38 patients. No cases of endobronchial intubation were detected in either group. The mean orotracheal tube-carina distance variation was estimated in -0.03cm (95% CI 0.06 to -0.13) in the group of patients undergoing open gastroplasty and in -0.42cm (95% CI -0.56 to -1.4) in the group of patients undergoing videolaparoscopic gastroplasty. The extremes of variation in each group were: 0.5cm to -1.6cm in patients undergoing open surgery and 0.1cm to -2.2cm in patients undergoing videolaparoscopic surgery.

CONCLUSIONS

There was no significant change in orotracheal tube-CA distance after placement of orthostatic retractors in patients undergoing open gastroplasty. There was a reduction in orotracheal tube-CA distance after insufflation of pneumoperitoneum in patients undergoing videolaparoscopic gastroplasty. We recommend attention to lung auscultation and to signals of ventilation monitoring and reevaluation of orotracheal tube placement after peritoneal insufflation.

Changes in cuff pressure and position of cylindrical-cuff and tapered-cuff tracheal tubes during laparoscopic abdominal surgery

Objectives

To evaluate changes in cuff pressure and position of tapered-cuff and cylindrical-cuff tracheal tubes (TTs) during laparoscopic cholecystectomy; to compare the frequency of endobronchial intubation and airway complaints with the two types of TT.

Methods

Patients were randomly assigned to intubation with a TT with a cylindrical cuff (group C) or a tapered cuff (group T). Anaesthesia was maintained with sevoflurane, O2 and N2O after intubation. TT cuffs were inflated to 20 cm H2O; changes in cuff pressure and volume were measured up to 30 min after the start of N2O use. Distance between the TT tip and the carina was measured before and after pneumoperitoneum and position change. Frequency of sore throat, dysphagia and hoarseness in the two groups was recorded.

Results

Cuff volume and pressure were significantly lower in group T than in group C ( n = 32 per group). Cuff pressure and volume significantly increased 30 min after start of N2O use in both groups. Distance from the TT tip to the carina decreased during surgery in both groups. There were no cases of endobronchial intubation, and there were no between-group differences in the frequency of airway complaints.

Conclusions

The tapered cuff was associated with a smaller change in cuff pressure during laparoscopic cholecystectomy than the cylindrical cuff, and therefore may be associated with increased preservation of tracheal mucosal perfusion.

Comparison of the endotracheal tube cuff pressure between a tapered- versus a cylindrical-shaped cuff after changing from the supine to the lateral flank position

PURPOSE

Positional change can displace an endotracheal tube (ETT) and change the ETT cuff pressure in a tracheally intubated patient. Endotracheal tubes with different cuff shapes may lead to different cuff pressures after positional change. We hypothesized that the intracuff pressure in the TaperGuard™ ETT with a tapered-shaped cuff would be higher than that in the conventional ETT with a cylindrical-shaped cuff after a change from the supine to the lateral flank position.

METHODS

Fifty-eight patients scheduled for open urological procedures in the lateral flank position were randomly allocated to receive either a TaperGuard ETT (group T) or conventional ETT (group C). The ETT cuff pressure was initially set at 20 cm H2O in the supine position and was measured after the change to the lateral flank position. The distance from the ETT tip to the carina was measured in both the supine and the lateral flank positions.

RESULTS

Two patients, one from each group, were excluded from the data analysis. The mean (SD) ETT cuff pressure was significantly higher in group T (n = 28) than in group C (n = 28) after the change in position [31 (7) cm H2O vs 25 (4) cm H2O, respectively; mean difference, 6 cm; 95% confidence intervals [CI], 3 to 9; P < 0.001]. The mean (SD) proximal migration of the ETT tip was comparable between the two groups [8 (18) mm vs 4 (14) mm, respectively; P = 0.367].

CONCLUSIONS

After the change from the supine to the lateral flank position, the ETT cuff pressure was significantly higher in the TaperGuard ETT than in the conventional ETT, although the extent of cephalad displacement of the ETT was comparable between the two groups. This trial was registered at Clinicaltrials.gov: NCT02165319.

Changes in endotracheal tube cuff pressure during laparoscopic surgery in head-up or head-down position

BACKGROUND

The abdominal insufflation and surgical positioning in the laparoscopic surgery have been reported to result in an increase of airway pressure. However, associated effects on changes of endotracheal tube cuff pressure are not well established.

METHODS

70 patients undergoing elective laparoscopic colorectal tumor resection (head-down position, n = 38) and laparoscopic cholecystecomy (head-up position, n = 32) were enrolled and were compared to 15 patients undergoing elective open abdominal surgery. Changes of cuff and airway pressures before and after abdominal insufflation in supine position and after head-down or head-up positioning were analysed and compared.

RESULTS

There was no significant cuff and airway pressure changes during the first fifteen minutes in open abdominal surgery. After insufflation, the cuff pressure increased from 26 ± 3 to 32 ± 6 and 27 ± 3 to 33 ± 5 cmH2O in patients receiving laparoscopic cholecystecomy and laparoscopic colorectal tumor resection respectively (both p < 0.001). The head-down tilt further increased cuff pressure from 33 ± 5 to 35 ± 5 cmH2O (p < 0.001). There six patients undergoing colorectal tumor resection (18.8%) and eight patients undergoing cholecystecomy (21.1%) had a total increase of cuff pressure more than 10 cm H2O (18.8%). There was no significant correlation between increase of cuff pressure and either the patient's body mass index or the common range of intra-abdominal pressure (10-15 mmHg) used in laparoscopic surgery.

CONCLUSIONS

An increase of endotracheal tube cuff pressure may occur during laparoscopic surgery especially in the head-down position.

Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: international standards guideline statement

Intraoperative neural monitoring (IONM) during thyroid and parathyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual nerve identification. Despite the increasing use of IONM, review of the literature and clinical experience confirms there is little uniformity in application of and results from nerve monitoring across different centers. We provide a review of the literature and cumulative experience of the multidisciplinary International Neural Monitoring Study Group with IONM spanning nearly 15 years. The study group focused its initial work on formulation of standards in IONM as it relates to important areas: 1) standards of equipment setup/endotracheal tube placement and 2) standards of loss of signal evaluation/intraoperative problem-solving algorithm. The use of standardized methods and reporting will provide greater uniformity in application of IONM. In addition, this report clarifies the limitations of IONM and helps identify areas where additional research is necessary. This guideline is, at its forefront, quality driven; it is intended to improve the quality of neural monitoring, to translate the best available evidence into clinical practice to promote best practices. We hope this work will minimize inappropriate variations in monitoring rather than to dictate practice options.

Beneficial effects of high positive end-expiratory pressure in lung respiratory mechanics during laparoscopic surgery

BACKGROUND

The effect of neuromuscular blockade (NMB) and positive end-expiratory pressure (PEEP) on the elastic properties of the respiratory system during pneumoperitoneum (PnP) remains a controversial subject. The main objective of the present study was to evaluate the effects of NMB and PEEP on respiratory mechanics.

METHODS

We performed a dynamic analysis of respiratory mechanics in patients subjected to PnP. Twenty-one patients underwent cholecystectomy videolaparoscopy and total intravenous anesthesia. The respiratory system resistance (R(RS)), pulmonary elastance (E(P)), chest wall elastance (E(CW)), and respiratory system elastance (E(RS)) were computed via the least squares fit technique using an equation describing the motion of the respiratory system, which uses primary signs such as airway pressure, tidal volume, air flow, and esophageal pressures. Measurements were taken after tracheal intubation, PnP, NMB, establishment of PEEP (10 cmH2O), and PEEP withdrawal [zero end-expiratory pressure (ZEEP)].

RESULTS

PnP significantly increased E(RS) by 27%; both E(P) and E(CW) increased 21.3 and 64.1%, respectively (P < 0.001). NMB did not alter the respiratory mechanic properties. Setting PEEP reduced E(RS) by 8.6% (P < 0.05), with a reduction of 10.9% in E(P) (P < 0.01) and a significant decline of 15.7% in R(RS) (P < 0.05). These transitory changes in elastance disappeared after ZEEP.

CONCLUSIONS

We concluded that the 10 cmH2O of PEEP attenuates the effects of PnP in respiratory mechanics, lowering R(RS), E(P), and E(RS). These effects may be useful in the ventilatory approach for patients experiencing a non-physiological increase in IAP owing to PnP in laparoscopic procedures.