Current concepts in airway management for cardiopulmonary resuscitation

An Airway Management Device: The Laryngeal Mask Airway—A Review

The laryngeal mask airway (LMA) is an airway management device that has become an accepted part of anesthetic practice in both pediatric and adults surgical patients. It is inserted without the use of a laryngoscope or muscle relaxants into the hypopharynx forming a low pressure seal around the glottis. The LMA provides a better airway than a face mask with or without an oral airway. Insertion techniques are quickly learned and are described in this review. Since the LMA forms a less secure seal than an endotracheal tube (ETT), several important limitations and contraindications exist. This includes patients at high risk for regurgitation of gastric contents into the lungs causing pulmonary aspiration and patients requiring high ventilatory pressures or prolonged ventilation. These contraindications have limited its introduction and utilization in the intensive care unit (ICU). The LMA is a helpful tool in the management of both the expected and unexpected difficult airway, where it may serve both as an emergency airway and as a conduit to intubation of the trachea with an ETT over a fiberoptic bronchoscope (FOB) or gum elastic bougie. A lifesaving airway has been provided by the LMA where no other means of achieving ventilation were possible in patients, including neonates, trauma victims, woman undergoing cesarean section, and in the setting of cardiac arrest. There are very few reported uses of the LMA in the ICU. We believe that familiarity with the LMA's design, use, and limitations by critical care practitioners will increase its use in emergency airway management and in the ICU. The LMA may prove to be the first of a new generation of airway devices placed into the hypopharynx to provide an alternative to the endotracheal tube and mask airway.

Ventilation performance of a mixed group of operators using a new rescue breathing device—the glossopalatinal tube

INTRODUCTION

We studied how effectively a mixed group of helpers could ventilate a manikin with a new rescue breathing device after a short period of instruction. The device consists of a mouthcap, a "glossopalatinal tube" (GPT) reaching between tongue and palate and a connector for a bag, ventilator or the rescuers mouth. Rather than reaching behind the tongue like an oropharyngeal airway (OP), it is able to scoop the tongue off the posterior pharyngeal wall when tilted by the rescuer. It was compared with a conventional face mask with an OP.

METHODS

The study made use of an anaesthesia simulator (MedSim Ltd., Israel) and a manikin. 46 subjects with different professional backgrounds (anaesthesia nurses, medical students, emergency medical technicians (EMTs), physicians training for anaesthesiology) underwent a standard introduction to the GPT and OP (lecture with demonstration on an intubation trainer, illustrated brochure). They ventilated the manikin for 5 min each using the bag plus GPT and the OP plus face mask, respectively, in random order after the simulator had been made apnoeic and the simulated arterial oxygen saturation (S(aO(2))) had dropped to 80%. The actions and the results (tidal volumes (V(t)), S(aO(2))) were recorded on video. The subjects graded difficulty of operation and fatigue on a visual analogue scale (VAS).

RESULTS AND CONCLUSIONS

Mean V(t) with the OP plus mask amounted to 463 (230-688 ml), with GPT to 426 (243-610 ml) (median [10-90% percentiles]) (P=0.047). No differences were observed with respect to the time a S(aO(2))> or =90% was maintained (OP plus mask: 255 (139-266 s), GPT: 255 (90-269 s)) or the grades for fatigue (OP plus mask: 58% of VAS, GPT: 48% of VAS, median) and difficulty (OP plus mask: 16% of VAS, GPT: 21% of VAS). Performance and grades were scattered over a wide range. Success with the two devices was correlated, but the subjects judgement tended to diverge. The GPT is an easy to learn alternative to conventional devices and might be helpful in clinical emergencies, including situations of unexpectedly difficult ventilation.

Current status of the Combitube: a review of the literature

The Combitube (Tyco-Healthcare-Kendall-Sheridan, Mansfield, MA) is an easily inserted and highly efficacious device to be used as an alternative airway whenever conventional ventilation fails. The Combitube allows ventilation and oxygenation whether the device locates in the esophagus (very common) or the trachea (rare). In this report, we review studies that suggest the Combitube is a valuable and effective airway in the emergency and prehospital settings, in cardiopulmonary resuscitation, in elective surgery, and in critically ill patients in the intensive care unit. Also reviewed are studies that demonstrate the superiority of the Combitube over other supraglottic ventilatory devices in resuscitation with respect to success rates with insertion and ventilation. Contrary to the Laryngeal Mask Airway, the Combitube may help in patients with limited mouth opening. The Combitube may be of special benefit in patients with massive bleeding or regurgitation, and it minimizes the risk of aspiration.

Airway management for the sports physician part 1: basic techniques

Airway emergencies are, fortunately, rare in sports medicine, but when they occur, they must be addressed quickly and effectively. Various techniques can be applied by a trained team physician to optimize oxygenation and ventilation for an acutely ill or injured athlete. Initial management of airway emergencies on the field can be guided using a simple algorithm. Basic maneuvers include methods to clear airways, place ventilation devices, and assist with breathing. More advanced techniques include placing various endotracheal tube devices and performing surgical techniques; these will be discussed in a subsequent article.

The respiratory system during resuscitation: a review of the history, risk of infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway

The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth ventilation. However, the benefit of basic life support for a patient in cardiopulmonary or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rate and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag-valve-mask ventilation of patients in respiratory or cardiac arrest with oxygen supplementation (> or = 40% oxygen), a tidal volume of 6-7 ml kg(-1) ( approximately 500 ml) given over 1-2 s until the chest rises is recommended. For bag-valve-mask ventilation with room-air, a tidal volume of 10 ml kg(-1) (700-1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. During mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of approximately 10 ml kg(-1) approximately 700-1000 ml in an adult) is recommended.

Resuscitation update for the pediatrician

Survival and neurologic outcome among pediatric patients in CPA have not improved measurably in the past decade, but the evolution of the pediatric Utstein guidelines has provided those involved in pediatric resuscitation a common language with which to exchange information and hopefully conduct meaningful research. The widespread use of the LMA may hold real promise for airway management of pediatric patients in the prehospital setting. Several of the developments in adult resuscitation, including ACD CPR and IAC CPR, seem auspicious for pediatric patients in cardiac arrest. At first glance, the widespread use of the AED would not be expected to alter the outcome of pediatric patients in CPA, but two studies suggest that ventricular fibrillation is more common in the pediatric population than originally believed, and thus the AED may have a significant role for this group of patients. The value of high-dose epinephrine remains controversial. All of these areas require research in the pediatric population before a judgment on their worth can be made. Research in pediatric resuscitation requires the study of larger populations, most feasibly with multicenter studies. How the "final rule" will influence this type of research remains to be seen. Finally, if investigators are to make real progress in improving the outcome of pediatric patients in CPA, they must concentrate their efforts on education of the lay public and enhancement of prehospital care.

Use of the laryngeal mask airway in air transport when intubation fails

BACKGROUND

A prospective, nonrandomized cohort study was conducted to determine the effectiveness of the laryngeal mask airway (LMA) for management of the difficult airway in patients requiring air transport.

METHODS

The LMA was inserted in those patients who could not be successfully intubated. Data were collected to evaluate the effectiveness of the LMA and to document any complications attributed to its use.

RESULTS

Inclusion criteria were met in 17 of the 25 patients receiving an LMA. The device was inserted successfully in 16 of 17 of the patients (94%). In-flight oxygen saturation ranged from 97 to 100%, and end-tidal carbon dioxide ranged from 24 to 35 mm Hg. At arrival, initial arterial blood gas values indicated adequate oxygenation in all patients and adequate ventilation in 15 of 16 patients (94%). There was no evidence of complications.

CONCLUSION

Our patient data show that when conventional methods have failed, the LMA can be safely, rapidly, and effectively used for temporary airway control.

Intubation of critically ill patients

Airway management of critically ill patients has been enhanced by the recent introduction of several new types of artificial airways and laryngoscopes. New drugs for sedation and neuromuscular blockade have been developed to facilitate care of the intubated patient. Guidelines for management of the difficult airway have been introduced. Several new prospective studies have improved our understanding of complications of intubation and how to avoid these sometimes tragic events. A consensus is evolving that TLI and tracheotomy each have clear advantages and disadvantages in prolonged airway maintenance and that multiple factors, not simply the duration of TLI, must be considered in the optimal timing of tracheotomy for each patient. Complex medicolegal and ethical issues directly impact intubation, perhaps more so than any other practice in critical care medicine. Physicians who care for critically ill patients should be familiar with these recent developments and concepts in airway management.