How Much Force Is Required to Dislodge an Alternate Airway?

Supraglottic airway device placement by respiratory therapists

OBJECTIVE

Respiratory Therapists (RTs) are some of the first staff to arrive at in-hospital incidents where cardiopulmonary resuscitation (CPR) is needed, yet at some facilities, their ability to intubate is limited by hospital scope of practice. During the intubation process, CPR is often interrupted which could potentially increase the likelihood of adverse patient outcomes. Training RTs to secure the airway using non-intubation methods may reduce or eliminate time for CPR interruptions and allow for earlier continuous/uninterrupted chest compressions.

DESIGN

A pilot study was developed to assess the effectiveness of a new policy for RT scope of practice.

METHODS

RTs were trained for supraglottic airway device placement prior to procedure initiation. After each device insertion event, RTs completed a written survey. Time between cardiac arrest and device insertion, number of insertion attempts, ease of placement, technical specifications of the device, complications, and survival were compiled and compared between supraglottic airway device and endotracheal tube (ETT) placement.

RESULTS

Procedural information from 23 patients who received a supraglottic airway device during the trial was compared to retrospective data of CPR events requiring intubation from the previous year. Time between initiation of cardiac arrest and advanced airway placement decreased significantly (p < 0.0001) when RTs placed the supraglottic airway device (4.7 min) versus ETT at CPR events the previous year (8.6 min). Device-associated complications were minimal and patient mortality was the same regardless of device.

CONCLUSION

We propose that more RTs should be trained to insert supraglottic airway devices during inpatient CPR events.

Comparison of the Force Required for Dislodgement Between Secured and Unsecured Airways

INTRODUCTION

Airway device placement and maintenance are of utmost importance when managing critically ill patients. The best method to secure airway devices is currently unknown.

STUDY OBJECTIVE

We sought to determine the force required to dislodge 4 types of airways with and without airway securing devices.

METHODS

We performed a prospective study using 4 commonly used airway devices (endotracheal tube [ETT], laryngeal mask airway [LMA], King laryngeal tube [King], and iGel) performed on 5 different mannequin models. All devices were removed twice per mannequin in random order, once unsecured and once secured as per manufacturers' recommendations; Thomas Tube Holder (Laerdal, Stavanger, Norway) for ETT, LMA, and King; custom tube holder for iGel. A digital force measuring device was attached to the exposed end of the airway device and gradually pulled vertically and perpendicular to the mannequin until the tube had been dislodged, defined as at least 4 cm of movement. Dislodgement force was reported as the maximum force recorded during dislodgement. We compared the relative difference in the secured and unsecured force for each device and between devices using a random-effects regression model accounting for variability in the manikins.

RESULTS

The median dislodgment forces (interquartile range [IQR]) in pounds for each secured device were: ETT 13.3 (11.6, 14.1), LMA 16.6 (13.9, 18.3), King 21.7 (16.9, 25.1), and iGel 8 (6.8, 8.3). The median dislodgement forces for each unsecured device were: ETT 4.5 (4.3, 5), LMA 8.4 (6.8, 10.7), King 10.6 (8.2, 11.5), and iGel 3.9 (3.2, 4.2). The relative difference in dislodgement forces (95% confidence intervals) were higher for each device when secured: ETT 8.6 (6.2 to 11), LMA 8.8 (4.6 to 13), King 12.1 (7.2 to 16.6), iGel 4 (1.1 to 6.9). When compared to secured ETT, the King required greater dislodgement force (relative difference 8.6 [4.5-12.7]). The secured iGel required less force than the secured ETT (relative difference -4.8 [-8.9 to -0.8]).

CONCLUSION

Compared with a secured device, an unsecured airway device requires only half the force to cause airway dislodgement. The secured King had the highest dislodgement force relative to the other studied devices.

Insertion Success of the Laryngeal Tube in Emergency Airway Management

Background. Emergency airway management (AM) is a priority when resuscitating critically ill or severely injured patients. The goal of this study was to determine the success rates of LT insertion during AM. Methods. Studies that included LT first-pass insertion (FPI) and overall-pass insertion (OPI) success by emergency medical services and in-hospital providers performing AM for emergency situations as well as for scheduled surgery published until July 2014 were searched systematically in Medline. Results. Data of 36 studies (n = 1,897) reported a LT FPI success by physicians of 82.5% with an OPI success of 93.6% (p < 0.001). A cumulative analysis of all 53 studies (n = 3,600) led to FPI and OPI success of 80.1% and 92.6% (p < 0.001), respectively. The results of 26 studies (n = 2,159) comparing the LT with the laryngeal mask airway (LMA) demonstrated a FPI success of 77.0 versus 78.7% (p = 0.36) and an OPI success of 92.2 versus 97.7% (p < 0.001). Conclusion. LT insertion failed in the first attempt in one out of five patients, with an overall failure rate in one out of 14 patients. When compared with the LT, the LMA had a cumulative 5.5% better OPI success rate.

Survey of Accepted Practice following Failed Intubation for Emergency Caesarean Delivery

Background. There is no consensus on the optimum management of failed tracheal intubation in emergency cesarean delivery performed for fetal compromise. The decision making process on whether to wake the patient or continue anesthesia with a supraglottic airway device is an underexplored area. This survey explores perceptions and experiences of obstetric anesthetists managing failed intubation. Methods. Anesthetists attending the Group of Obstetric Anaesthetists London (GOAL) Meeting in April 2014 were surveyed. Results. Ninety-three percent of anesthetists surveyed would not always wake the patient in the event of failed intubation for emergency cesarean delivery performed for fetal compromise. The median (interquartile range) of perceived acceptability of continuing anesthesia with a well-fitting supraglottic airway device, assessed using a visual analogue scale (0–100; 0 completely unacceptable; 100 completely acceptable), was 90 [22.5]. Preoperative patient consent regarding the use of a supraglottic airway device for surgery in the event of failed intubation would affect the decision making of 40% of anaesthetists surveyed. Conclusion. These results demonstrate that a significant body of anesthetists with a subspecialty interest in obstetric anesthesia in the UK would not always wake up the patient and would continue with anesthesia and surgery with a supraglottic airway device in this setting.

Extubation force depends upon angle of force application and fixation technique: a study of 7 methods

BACKGROUND

Endotracheal tubes are frequently used to establish alternate airways. Precise placement of the tubes must be maintained to prevent serious complications. Several methods for fixation of endotracheal tubes are available. Available methods vary widely in form and functionality. Due to the unpredictable and dynamic nature of circumstances surrounding intubation, thorough evaluation of tube restraints may help reduce airway accidents such as tube dislodgement and unplanned extubation.

METHODS

Seven different tube-restraint combinations were compared against themselves and one another at a series of discrete angles (test points) covering a hemisphere on the plane of the face. Force values for tube motion of 2 cm and 5 cm (or failure) were recorded for 3 pull tests, at each angle, for each method of tube fixation.

RESULTS

All methods showed variation in the force required for tube motion with angle of force application. When forces were averaged over all test points, for each fixation technique, differences as large as 132 N (30 lbf) were observed (95% CI 113 N to 152 N). Compared to traditional methods of fixation, only 1 of the 3 commercially available devices consistently required a higher average force to displace the tube 2 cm and 5 cm. When ranges of force values for 5 cm displacement were compared, devices span from 80-290 N (18-65 lbf) while traditional methods span from 62-178 N (14-40 lbf), highlighting the value of examining forces at the different angles of application. Significant differences in standard deviations were also observed between the 7 techniques indicating that some methods may be more reproducible than others.

CONCLUSIONS

Clinically, forces can be applied to endotracheal tubes from various directions. Efficacies of different fixation techniques are sensitive to the angle of force application. Standard deviations, which could be used as a measure of fixator reliability, also vary with angle of force application and method of tube restraint. Findings presented in this study may be used to advance clinical implementation of current methods as well as fixator device design in an effort to reduce the incidence of unplanned extubation.

Can emergency medical services personnel effectively place and use the Supraglottic Airway Laryngopharyngeal Tube (SALT) airway?

BACKGROUND

Various alternative airway devices have been developed in the last several years. Among these is the Supraglottic Airway Laryngopharyngeal Tube (SALT), which was designed to function as a basic mechanical airway and as an endotracheal tube (ET) introducer for blind endotracheal intubation (ETI).

OBJECTIVE

To determine the rate of successful placement of the SALT and the success rate of subsequent blind ET insertion by a cohort of emergency medical services (EMS) providers of varying levels of EMS certification.

METHODS

This study was a two-phase, two-group nonblinded, prospective time trial using a convenience cohort of prehospital providers to determine the success rate for SALT placement (i.e., the basic life support [BLS] phase) and ET placement using the SALT (i.e., the advanced life support [ALS] phase) in an unembalmed human cadaver model. The part 1 cohort (group 1) comprised predominantly basic and intermediate emergency medical technician (EMT)-level providers, whereas the part 2 cohort (group 2) comprised exclusively paramedic-level providers.

RESULTS

In group 1, 51 (98%) of the subjects were able to successfully place the SALT and ventilate the cadaver (BLS phase), with 48 (92.3%) subjects successfully placing it on the first attempt. In group 2, 21 (96%) of the subjects were able to successfully place the SALT, with 19 (86%) placing the SALT on the first attempt. Successful blind placement of an ET through the SALT (ALS phase) by group 1 was 48.1% (95% confidence interval [CI]: 34-62), with 37% (95% CI: 24-51) placing the ET on the first attempt. In group 2, 20 subjects (91% [95% CI: 71-99]) were able to successfully place an ET through the SALT, with 13 (59% [95% CI: 36-79]) doing so on the first attempt.

CONCLUSIONS

Emergency medical services providers of varying levels can successfully and rapidly place the SALT and ventilate a cadaver specimen. The success rate for blind placement of an ET through the SALT was suboptimal.

Prehospital pediatric King LT-D use: a pilot study

OBJECTIVE

To determine whether prehospital providers can successfully place a pediatric King laryngeal tube (LT-D) and ventilate a Laerdal SimBaby pediatric simulator during a respiratory arrest simulation.

METHODS

We studied the ability of 45 paramedics and flight nurses to place the pediatric King LT-D in a SimBaby manikin. For the purposes of this study, paramedics and flight nurses were considered equivalent, because in this air medical system they have the same scope of practice in regard to airway skills. Because the participants had previous training and field experience with the adult King LT-D, we limited pediatric King LT-D training to our standard adult training plus selecting the correct size and inflation volumes for the device. Outcomes included rate of successful pediatric King LT-D placement, number of attempts to correctly place the tube, and time to first adequate ventilation. The subjects were evaluated on airway management using an 11-point skill test. A score of 8 or greater (≥ 73%) was considered passing. The subjects indicated their perceptions and preferences for the pediatric King LT-D using a five-point Likert scale. Data were analyzed using descriptive statistics.

RESULTS

Crew members successfully placed the pediatric King LT-D 95.5% (43/45) of the time. The median number of attempts was one. Four subjects required a second attempt; two of these subjects failed at placement. Mean time to placement was 34 seconds (95% confidence interval [CI]: 26.4-67.3 sec). Ninety percent of the participants (40/45) successfully completed the skill test, with a mean score of 78.2% (95% CI: 73.6-82.7). The subjects strongly agreed that their previous training on the adult King LT-D and using it in the field had adequately prepared them to use the pediatric King LT-D. The subjects agreed that the pediatric King LT-D was easier to place than a pediatric endotracheal tube; they strongly agreed that they would use the pediatric King LT-D as an alternative airway. The participants disagreed that they would prefer the pediatric King LT-D as a primary means of securing pediatric airways.

CONCLUSIONS

The pediatric King LT-D was quickly and reliably placed. Providers perceived the pediatric King LT-D to be easier to use than pediatric endotracheal intubation in this setting.