Thenar eminence based medicine

June 3, 2013 by  
Filed under All Updates, EMS, ICU, Kids, Resus, Trauma

thumbs-upA recent study showed superior effectiveness of one bag-mask ventilation style over another in novice providers. The technique recommended is the thenar eminence grip, in which downward pressure is applied with the thenar eminences while the four fingers of each hand pull the jaw upwards toward the mask.

Interestingly, in their crossover study in which the thenar emininence (TE) technique was compared with the traditionally taught ‘CE’ technique, they demonstrated a ‘sequence effect’. If subjects did TE first, they maintained good tidal volumes when doing CE. However if they did CE first, they achieved poor tidal volumes which were markedly improved when switching to TE.

The authors suggest: “A possible explanation for this sequence effect is that the TE grip is superior. When one used the TE grip first, he or she was more likely to learn how a good tidal volume “feels” and then more likely to apply good technique with the EC grip.“.

Some of us have been practicing and teaching this technique for a while. None have put it better than the brilliant Reuben Strayer of EM Updates in this excellent short video:


Efficacy of facemask ventilation techniques in novice providers
J Clin Anesth. 2013 May;25(3):193-7


STUDY OBJECTIVE: To determine which of two facemask grip techniques for two-person facemask ventilation was more effective in novice clinicians, the traditional E-C clamp (EC) grip or a thenar eminence (TE) technique.

DESIGN: Prospective, randomized, crossover comparison study.

SETTING: Operating room of a university hospital.

SUBJECTS: 60 novice clinicians (medical and paramedic students).

MEASUREMENTS: Subjects were assigned to perform, in a random order, each of the two mask-grip techniques on consenting ASA physical status 1, 2, and 3 patients undergoing elective general anesthesia while the ventilator delivered a fixed 500 mL tidal volume (VT). In a crossover manner, subjects performed each facemask ventilation technique (EC and TE) for one minute (12 breaths/min). The primary outcome was the mean expired VT compared between techniques. As a secondary outcome, we examined mean peak inspiratory pressure (PIP).

MAIN RESULTS: The TE grip provided greater expired VT (379 mL vs 269 mL), with a mean difference of 110 mL (P < 0.0001; 95% CI: 65, 157). Using the EC grip first had an average VT improvement of 200 mL after crossover to the TE grip (95% CI: 134, 267). When the TE grip was used first, mean VTs were greater than for EC by 24 mL (95% CI: -25, 74). When considering only the first 12 breaths delivered (prior to crossover), the TE grip resulted in mean VTs of 339 mL vs 221 mL for the EC grip (P = 0.0128; 95% CI: 26, 209). There was no significant difference in PIP values using the two grips: the TE mean (SD) was 14.2 (7.0) cm H2O, and the EC mean (SD) was 13.5 (9.0) cm H2O (P = 0.49).

CONCLUSIONS: The TE facemask ventilation grip results in improved ventilation over the EC grip in the hands of novice providers.

Comments

2 Responses to “Thenar eminence based medicine”

  1. Karel Habig on June 3rd, 2013 22:39

    Great post on an issue very close to my heart. I liked the video from Reuben Strayer (hadn’t seen it before). I very much agree that the thenar eminence technique (which I have been teaching as the “thumbs to toes” technique) is superior to CE in the setting of critical care. I would make one small suggestion – that you try the technique with the index finger under the angle of the mandible. The increased strength of the index finger compared with the little finger pulling the mandible forward creates a significantly more powerful jaw thrust and thus opens the airway more effectively. It is not always possible for those with very small hands but I have seen many smiles of realisation from anaesthetic specialists when shown the technique. Try it on a mannequin when you next get the chance. See how it feels in comparison to CE!
    Cheers,
    Karel Habig

  2. Christopher on June 3rd, 2013 23:31

    I’ve been using this video when teaching BLS classes since Dr. Strayer put it out there. Absolutely fantastic teaching resource!