Prehospital airway management with the laryngeal mask airway in polytraumatized patients

Airway management techniques in a restricted-access situation: a manikin study

BACKGROUND

Access to patients can be restricted in emergency situations. A variety of techniques and devices are available for use in patients who require oxygenation in a restricted-access situation.

OBJECTIVES

The aim of this study was to investigate whether there is one ventilation technique that is superior to others.

MATERIALS AND METHODS

Fifty-four emergency medical services providers including emergency medical technicians, paramedics and physicians were asked to use a bag-valve mask (BVM), a laryngeal mask airway (LMA), and a laryngeal tube (LT) to ventilate a full-scale manikin sitting upright in the driver's seat of a motor vehicle. Access to the manikin was gained through the side window and from the backseat.

RESULTS

There were significant differences in time to first successful ventilation between the two approaches for access to the airway. The fastest median time to ventilation was obtained with the BVM (7 and 8 s), followed by the LT (13 and 14 s) and the LMA (15 s for both types of access). Overall success rates were 97.2% for the BVM, 96.3% for the LMA, and 100% for the LT. Most participants needed two attempts for each device. There were no significant differences between participants depending on the level of qualification or professional experience. The BVM was rated the lowest and the LT was rated the highest for ease of use.

CONCLUSION

Supraglottic airway devices appear to offer advantages in restricted-access situations.

A STANDING-ORDERPROTOCOL FORCRICOTHYROTOMY INPREHOSPITALEMERGENCYPATIENTS

OBJECTIVE

To study utilization, indications, and outcomes associated with the use of a statewide, emergency medical services (EMS) standing-order protocol for cricothyrotomy.

METHODS

A statewide EMS database was queried for patients who received cricothyrotomy under a standardized, standing-order protocol. Patient EMS and hospital records were reviewed in a defined sequence with information recorded on a standardized collection form.

RESULTS

EMS records included eight years of practice with 1.5 million patient encounters. For each year studied, approximately 540 emergency medical technicians (EMTs) were certified to perform cricothyrotomy. State EMS providers performed a collective mean of eight cricothyrotomy procedures per year (range, 1-17), for a total of 68 cricothyrotomies performed within the eight-year period. Hospital records were available for review in 61 patients. Fifty-six patients received cricothyrotomy by open surgical incision, six by needle with jet ventilation, and one by both methods. Categorization of cricothyrotomy patients as trauma or medical was 61% trauma and 39% medical. Thirty-six patients (59%) were in cardiac arrest on EMS arrival and 12 patients (20%) died during transport. Thirteen trauma patients (21%) were admitted with eight patients surviving to discharge (13%). The neurologic impairment at time of hospital discharge was severe in four, moderate in two, and minimal or none in two patients (3%).

CONCLUSION

A considerable percentage of cricothyrotomy procedures were performed on patients with non-trauma-related diagnoses in this investigation describing a standing-order EMS protocol for cricothyrotomy. The majority of patients undergoing cricothyrotomy with this protocol were in cardiac arrest at the time of cricothyrotomy, with a small minority of patients surviving to hospital discharge and fewer surviving neurologically intact.

An Algorithmic Approach to Prehospital Airway Management

Airway management, including endotracheal intubation, is considered one of the most important aspects of prehospital medical care. This concept paper proposes a systematic algorithm for performing prehospital airway management. The algorithm may be valuable as a tool for ensuring patient safety and reducing errors as well as for training rescuers in airway management.

Comparative study of airway management techniques with restricted access to patient airway

OBJECTIVE

To determine which airway endotracheal tube (ET), Combitube (CT), or Laryngeal Mask Airway (LMA) has the shortest time to successful ventilation in three nontraditional prehospital airway scenarios.

METHODS

Prospective randomized cohort study of emergency medicine (EM) residents, faculty EM physicians, and paramedics (EMT-P). Subjects were instructed to place an airway in a mannequin in three scenarios: mannequin supine under a table with head abutting a wall, mannequin sitting upright with access from behind, and mannequin lying on its side with access facing the mannequin. The number of airway placement attempts and time to successful ventilation were recorded.

RESULTS

Twenty-five resident physicians, 9 faculty physicians, and 22 EMT-Ps participated. No significant difference was found between the different airways in the number of attempts to successfully ventilate. EMT-Ps demonstrated significantly faster times to successful ventilation for all scenarios versus physicians (e.g., supine scenario with ET, EMT-P median time 57 seconds, physician median time 96 seconds) except for the mannequin lying on its side where there was no significant difference. The time to ventilation for all scenarios was less with the LMA versus ET or CT versus ET, except in the sitting scenario where ET and CT were comparable.

CONCLUSIONS

In this mannequin model of restricted airway access, LMA resulted in significantly faster times to ventilation versus ET and CT in all but one scenario. Further consideration and study using airways other than ET are warranted for situations with restricted access to the patient's airway.

Anesthesiologists on ambulances: where do we stand?

PURPOSE OF REVIEW

This manuscript provides a critical review of the literature regarding the staffing of emergency medical services, with particular emphasis on anesthesiologists.

RECENT FINDINGS

Significant anesthesiology contributions to prehospital care include introduction of new airway management tools and improved physiological monitoring. Contributions to quality of care include patient benefit in terms of life years gained and a specific reduction in mortality from acute myocardial infarction. Intuitive concepts regarding the advantage of anesthesiologists in intubation mishaps and management of the failed airway have yet to be proven. Personnel limitations may be regional, necessitating local evaluation of anesthesiologist availability to staff ambulances. Since a major part of cost-effectiveness research is performed in the US where only paramedics staff ambulances, insufficient data exist regarding the financial implications of such practice. Burnout may be an important factor for deciding whether anesthesiologists should work in the operating room or ambulances or on an alternate basis.

SUMMARY

Further research should be performed to evaluate the clinical and financial implications of staffing ambulances with anesthesiologists or other physicians. Randomized controlled studies using standardized intubation techniques are necessary to examine whether prehospital airway management is improved when delivered by anesthesiologists.

Securing the prehospital airway: a comparison of laryngeal mask insertion and endotracheal intubation by UK paramedics

OBJECTIVES

The recent introduction of a disposable laryngeal mask airway has provided paramedics with an alternative to endotracheal intubation. Time taken to secure the airway with each device was compared in patients undergoing elective surgery.

METHODS

Patients undergoing general anaesthesia were studied. Paramedics trained in laryngeal mask use and endotracheal intubation participated in the study. A Portex disposable laryngeal mask was inserted and removed, followed by a Portex endotracheal tube. Time taken from beginning of the procedure to ventilation of the patient was recorded.

RESULTS

Laryngeal mask insertion and endotracheal intubation was attempted on 52 patients. Median age was 63.5 years (range 39-83). Laryngeal mask insertion was successful in 88.5% (46 of 52) patients; endotracheal intubation was successful in 71.2% (37 of 52) patients (after no more than two attempts), p = 0.049. Intubation success was related to laryngoscopic view (87.5% grade 1, 56.3% grade 2, 0.0% grade 3. p<0.0001). When laryngeal mask/endotracheal tube insertion were both successful (n = 35 of 52), there was no significant difference in median time to secure the airway (laryngeal mask 47.0 seconds (range 24-126) compared with endotracheal tube 52.0 seconds (range 27-148) p = 0.22). Laryngeal mask insertion was successful in 80.0% (12 of 15) patients in whom endotracheal intubation had failed.

CONCLUSIONS

Even under optimal conditions, 30% of attempts at intubation by paramedics were unsuccessful. A disposable laryngeal mask has a higher success rate in securing the airway and overall, secures the airway more reliably than endotracheal intubation.

Blind tracheal intubation by paramedics through the LMA-Unique

OBJECTIVE

The manufacturer of the laryngeal mask airway (LMA) reports success rates of 30-93% by practitioners attempting tracheal intubation through the LMA-Classic. No prior studies describe success rates through the (disposable) LMA-Unique by paramedics. The objective of this study was to measure the success rate of paramedics attempting to intubate the trachea blindly through the LMA-Unique.

METHODS

During a paramedic refresher class and an emergency medical services teaching day conference, paramedics previously trained in the use of the LMA-Unique as a "rescue" airway device were instructed in the technique of tracheal intubation through the LMA-Unique. A Laerdal LMA-mannequin was immobilized with an extrication collar and held by an investigator in the head-neutral position. Paramedics were first asked to insert the LMA-Unique as previously trained, and to confirm adequate ventilation by seeing inflation of the mannequin's lungs. Then, subjects were asked to pass a well-lubricated 6-0 Mallinckrodt endotracheal tube through the LMA-Unique within a 60-second period. Tracheal placement of the endotracheal tube was then confirmed by visualization of the expanding mannequin lungs. Rates of success of LMA-Unique placement and endotracheal tube placement were measured.

RESULTS

Fifty of the 52 (96%; CI 91% to 100%) paramedics successfully inserted the LMA-Unique on the first attempt. Only 11 of the 52 (21%; CI 10% to 32%) paramedics were successful in blind placement of the endotracheal tube into the trachea through the LMA-Unique within a 60-second period. The failures (41 of the 52) were visually confirmed to be located in the esophagus.

CONCLUSION

In this study, when attempting blind tracheal intubation through the LMA-Unique, paramedics were rarely successful in tracheal placement. Basic LMA-Unique insertion, however, had a very high success rate.