“Control your environment – don’t let it control you” is a reliable adage for pre-hospital providers, and its adherence can assist in in-hospital resuscitation too. Commanding control of ones space is a skill demonstrated by more seasoned paramedics compared with novices and the requirement, where possible, for 360 degrees of access around a patient is included in some Standard Operating Procedures for pre-hospital rapid sequence intubation.

Evidence for this approach is now further supported by a study demonstrating that limited surrounding space on scene was a significant risk factor for difficult pre-hospital intubation by European EMS physicians.
Other predisposing factors for difficult prehospital intubation included obesity and a short neck.

OBJECTIVES:For experienced personnel endotracheal intubation (ETI) is the gold standard to secure the airway in prehospital emergency medicine. Nevertheless, substantial procedural difficulties have been reported with a significant potential to compromise patients’ outcomes. Systematic evaluation of ETI in paramedic operated emergency medical systems (EMS) and in a mixed physician/anaesthetic nurse EMS showed divergent results. In our study we systematically assessed factors associated with difficult ETI in an EMS exclusively operating with physicians.

METHODS:Over a 1-year period we prospectively collected data on the specific conditions of all ETIs of two physician staffed EMS vehicles. Difficult ETI was defined by more than 3 attempts or a difficult visualisation of the larynx (Cormack and Lehane grade 3, or worse). For each patient ETI conditions, biophysical characteristics and factors of the surrounding scene were assessed. Additionally, physicians were asked whether they had expected difficult ETI in advance.

RESULTS:Out of 3979 treated patients 305 (7.7%) received ETI. For 276 patients complete data sets were available. The incidence of difficult ETI was 13.0%. In 4 cases (1.4%) ETI was impossible, but no patient was unable to be ventilated sufficiently. Predicting conditions for difficult intubation were limited surrounding space on scene (p<0.01), short neck (p<0.01), obesity (p<0.01), face and neck injuries (p<0.01), mouth opening<3cm (p<0.01) and known ankylosing spondylitis (p<0.01). ETI on the floor or with C-spine immobilisation in situ were of no significant influence. The incidence of unexpected difficult ETI was 5.0%.
CONCLUSIONS: In a physician staffed EMS difficult prehospital ETI occurred in 13% of cases. Predisposing factors were limited surrounding space on scene and certain biophysical conditions of the patient (short neck, obesity, face and neck injuries, and anatomical restrictions). Unexpected difficult ETI occurred in 5% of the cases.

Difficult prehospital endotracheal intubation – predisposing factors in a physician based EMS
Resuscitation. 2011 Dec;82(12):1519-24