Rescuer position for tracheal intubation on the ground

doi:10.1016/S0300-9572(02)00293-9

Resuscitation

Volume 56, Issue 1, January 2003, Pages 83-89

https://doi.org/10.1016/S0300-9572(02)00293-9 Get rights and content

Abstract

Background: Emergency oral tracheal intubations in the pre-hospital setting can be more difficult because the rescuer's position with respect to a patient lying on the ground may not provide optimal conditions for intubation. Since optimal visualisation of the larynx often depends on the force generated during laryngoscopy, we measured the pressure required for intubation (P_i) as well as the maximum pressure (P_max) that can be generated with the laryngoscopy blade in seven intubator positions. Methods: Nineteen hospital personnel with intubation experience participated in this study. A modified #3 Macintosh laryngoscope blade was used to measure the pressure exerted on the tongue of a manikin placed on the ground during intubation. The following positions were studied: standard, sitting, prone, kneeling, left and right lateral decubitus and straddling. Results: Intubating in the straddling position required the lowest P_i, as a percent of P_max (68±14%). This was significantly less than the prone, right lateral decubitus and sitting positions. (Tukey's W procedure, P<0.05) Conclusion: The straddling position affords the intubator significantly more reserve force than the prone, right lateral decubitus or sitting position. We suggest that the straddling position may be an advantageous position for pre-hospital intubations especially when visualisation of the glottis is difficult.

Sumàrio

Tese: A intubação endotraqueal de emergência no pré-hospitalar pode ser mais difı́cil porque a posição do reanimador em relação ao doente, no chão, pode não proporcionar condições óptimas para intubação. Como as condições de visualização óptima da laringe dependem frequentemente da força gerada durante a laringoscopia, medimos a pressão necessária para intubação (P_i) tal como a pressão máxima (P_máx) gerada pela lâmina do laringoscópio em 7 posições diferentes. Métodos: Participaram neste estudo 19 elementos hospitalares com experiência de intubação. Foi usada uma lâmina de laringoscópio #3 Macintosh modificada para medir a pressão exercida na lı́ngua de um manequim colocado no chão durante a intubação. Foram estudadas as seguintes posições: standard, sentado, ventral, de joelhos, decúbito lateral direito e esquerdo e de pernas abertas. Resultados: A intubação na posição de pernas abertas exigiu a menor P_i, como percentagem da P_máx (68±14%). Isto era significativamente menos do que as posições ventral, decúbito lateral direito e sentado. (Procedimento W de Tukey, P<0,05). Conclusão: A posição de pernas abertas permite entubar poupando significativamente mais força do que a ventral, decúbito lateral direito ou sentado. Sugerimos que a posição de pernas abertas pode ser vantajosa para intubações pré-hospitalares em especial quando a visualização da glote é difı́cil.

Resumen

Antecedentes: La intubación oro traqueal de emergencia en el ambiente prehospitalario puede ser mas difı́cil, debido a la posición del reanimador con respecto al paciente que yace sobre el suelo puede no proporcionar condiciones óptimas para la intubación. Dado que la visualización óptima de la laringe frecuentemente depende de la fuerza generada durante la laringoscopı́a, medimos la presión requerida para intubación (P_i) al igual que la presión máxima (P_max) que puede ser generada con la hoja del laringoscopio en siete posiciones de intubación. Métodos: Participaron en este estudio 19 personal hospitalario con experiencia en intubación. Se usó una hoja de laringoscopio Macintosh # 3 modificada para medir la presión ejercida sobre la lengua de un maniquı́ ubicado en el suelo durante la intubación.. Las siguientes posiciones fueron estudiadas: estándar, sentado, prono, arrodillado, decúbito lateral derecho, decúbito lateral izquierdo y a horcajadas. Resultados. Intubando horcajadas requirió la menor presión de intubación, expresada como porcentaje de la presión máxima (68±14%).Esta fue significativamente menor que en posición prona, decúbito lateral derecho y posición sentado. (Procedimiento de Turkey's W, P<0.05). Conclusión: La posición a horcajadas, permite al operador que está intubando, una reserva de fuerza significativamente mayor que las posiciones prona, decúbito lateral derecho, o posición sentado. Sugerimos que la posición a horcajadas puede ser ventajosa para intubación prehospitalaria, especialmente cuando la visualización de la glotis es dificultosa.

Introduction

For a rescuer attending an unconscious patient outside of the hospital setting, the ability to secure the airway rapidly may be the critical life-saving manoeuvre. Oral tracheal intubation is the most reliable means of establishing control of the airway. Intubation may be awkward when the patient is lying on the ground and the rescuer is forced to assume crouching or lying positions to obtain adequate visualisation of the larynx.

Several studies have endeavoured to determine the optimal rescuer position for intubating patients lying supine on the ground. Adnet et al. found the left lateral decubitus (LLD) position to afford better glottic exposure than the kneeling position in both manikins [2] and patients [3]. However, Koetter et al. [1] found that the time differences to intubation of a manikin in four positions (prone, sitting, kneeling and straddling) were clinically insignificant (<5 s). They found no significant differences between the positions with respect to subjective handling and complications. Birkinshaw et al. [4] found that none of 10 intubator positions studied on manikins were superior statistically with respect to speed or ease of intubation. This lack of significance may have been because a standard training manikin has an uncomplicated airway and experienced rescuers will have little trouble performing airway intubation in less than the AHA recommended time of 30 s [5] regardless of their position. However, it may take a rescuer considerably longer to intubate a real patient—especially one with non-optimal airway anatomy—from an awkward body position. In such real-life situations, the force that can be exerted to align and visualize the soft tissues may determine the quality of access to the airway [6], [7], [8], [9] and hence the chance of successful intubation.

Our aim was to study the effect of seven rescuer positions on the maximum force that the rescuer can apply in that position. We compared this to the force exerted by the rescuer to align the soft tissues of the pharynx for tracheal intubation. The ratio of these two forces was taken as an indication of the ‘reserve force’ available in case of difficulty in visualisation of the larynx.

Section snippets

Subjects

Twelve male and eight female subjects with a variable amount of previous intubation experience volunteered for this study. The participants consisted of six respiratory therapists, one medical student, seven anaesthesia residents, three anaesthesia fellows and three staff anesthesiologists. Their mean age was 32±6 years (range 25–48 years), and their mean height was 171±7.3 cm (range 157–183 cm). Sixteen volunteers were right-handed and four were left-handed. Mean intubation experience was

Results

Values for P_i, P_max and %_max as well as results from all pair-wise comparisons are provided in Table 1. The pressure required to intubate was highest in the sitting position and this was significantly greater than all other positions except for LLD. The straddling and LLD positions afforded the greatest maximal pressure, and these pressures were significantly greater than RLD, kneeling and prone. The straddling position required only 68% of maximal pressure to intubate and this was

Discussion

The results of this study indicate that of the 7 positions, the straddling position provides the rescuer with the greatest reserve of force available to align the soft tissues with the laryngoscope during intubation. The straddling position has several major advantages over the other positions studied. First, the laryngoscope is held in the right hand (dominant for most people). Second, laryngoscopy is achieved through extension of the shoulder and flexion of the elbow, which uses powerful

Conclusion

We found that compared to the other positions studied, the straddling position allows the rescuer to apply greater force on the soft tissue to facilitate visualisation of the larynx. In addition, the straddling position has further advantages in that it (a) may provide better access to patients who are trapped in confined spaces and (b) would be less likely to expose the rescuer to hazardous material on the ground. We recommend that the straddling position become part of the standard training

Acknowledgements

The authors would like to acknowledge the staff members of the University Health Network's Respiratory Therapy and Anaesthesia departments for their participation and co-operation.

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Rescuer position for tracheal intubation on the ground

Abstract

Sumàrio

Resumen

Introduction

Section snippets

Subjects

Results

Discussion

Conclusion

Acknowledgements

Am. J. Emerg. Med.

Resuscitation

Am. J. Emerg. Med.

A randomized comparison of rescuer positions for intubation on the ground

Prehosp. Emerg. Care

Emergency tracheal intubation of patients lying supine on the ground: influence of operator body position

Can. J. Anaesth.

Intubation in difficult positions

Pre-hosp. Imm. Care