Let me see (BOTH) your hands! BVM technique in resus

keep-calm-and-let-me-see-your-hands-jpgLet’s face it – when it comes to riding bicycles, inserting cannulas, tying knots, and even manipulating lingerie, fewer hands is just better, right? Well not so fast. Sometimes it’s preferable to play it safe.  Keep your eyes on the road. Even ride with stabilisers on.

This couldn’t apply more when it comes to manual ventilation of the acutely unwell patient. It’s still ubiquitous to see colleagues in the resuscitation room using a single-operator Bag Valve Mask (BVM) technique, in many cases struggling to ventilate the patient.

A senior colleague of mine regularly refers to ‘a time and a place’ for the use of various practical techniques. There is, in general, a time and a place for the use of single-operator BVM, but not in the resuscitation room in my opinion.

The simplified ready-to-use  BVM concept was conceived in 1953 by Holger Hesse and his partner Henning Ruben, following their initial work on a suction pump. Their resuscitator was named “Ambu” – Artificial Manual Breathing Unit. Hesse doesn’t specify in his patent for the original Ambu bag, filed in 1965, whether a single operator would both ventilate and secure the mask (wouldn’t it be great to travel back in time and witness the original demonstrations on his equally innovative resuscitation mannequins?).

Anaesthetists have, in general, shown preference for the one-handed ‘CE’ BVM technique (with Ambu-bags and breathing circuits), allowing a single operator to ventilate and perform airway protection manoeuvres.  The CE technique is practical and advantageous during anaesthetic induction as it is important to be able to bag a patient alone, with minimal assistance, during a well-rehearsed routine. Furthermore, the vast majority of elective anaesthetic inductions are safe and uneventful.

The mid-1980s onwards has seen the emergence of evidence supporting the ventilatory superiority of two-handed BVM techniques, namely the thenar eminence technique (AKA the ‘two thumbs up approach’), or the two-handed CE technique. A small clinical measurement study by Manoranjan Jesudian’s group in 1985 showed that tidal volumes in two-person BVM were significantly larger then when used by a single operator. This result has been replicated multiple times: a study by University of New Mexico School of Medicine showed that a thenar eminence technique improved tidal volumes over the single CE grip; a prospective study in Minneapolis showed that in 70 patients, both the two-handed CE technique and a thenar eminence technique delivered superior tidal volumes to the one-handed CE technique. One of the most cited publications (and one of the most rigorous) was by Joffe et al 2010, published in Anesthesiology, which showed superiority of a two handed jaw-thrust mask technique, again using corrected tidal volumes as a comparator.

BVM  is a crucial emergency resuscitation skill – often described as the most important one (‘A’ is for Airway after all). As is often the case, the technique appears deceptively simple. In reality, it can be difficult to perform correctly and effectively; either due to patient or provider factors. Novice operators (e.g. during Basic Life Support) are generally less effective, and patient factors such as obesity, facial hair, elderly patients or those with Sleep Apnoea make BVM more difficult to perform effectively.

Putting this together it would seem to me that BVM ventilation needs to be thought of differently when being used in various locations, even though the equipment is the same.  This is true of many medical ‘rules of thumb’. An intensivist, for example, will be much more liberal with the dosing of intravenous narcotic analgesia or sedation in an intubated patient than an emergency physician will be in an awake elderly patient during procedural sedation. As acute generalists, EPs need to be prepared to perform a variety of emergency procedures safely, despite not having performed the procedure in question as frequently as a specialist. We may not be inserting as many chest drains as a respiratory physician, or intubating as many patients as an anaesthetist, but we are expected to be safe. With this in mind, we must prepare diligently and make life as easy for ourselves as possible peri-procedure: routine use of a Gum Elastic Bougie during intubation for example, or indeed the use of a two-handed BVM technique.

It’s worth mentioning that the take-home message from this post is summarised (with wit and lore) by Reuben Strayer in the video embedded below. I’m not saying that the CE technique isn’t valuable. In fact, if it’s working, by all means use it. But next time you see a patient’s saturations dropping during a BVM, lend a hand, or better two.

Adam Walker

This topic has been touched on by a previous Pondering EM blog post – Pearls from ‘Critical Care in the ED’ – a Cliff Reid Masterclass.

References

  1. Respiration bag, US patent 3255677. https://www.google.co.uk/patents/US3255677
  2. Crit Care Med. 1985 Feb;13(2):122-3. Bag-valve-mask ventilation; two rescuers are better than one: preliminary report. Jesudian et al. PMID: 3967502
  3. J Emerg Med. 2013 May;44(5):1028-33. Face mask ventilation: a comparison of three techniques. Hart et al. PMID: 23473817
  4. Langeron O, Masso E, Huraux C, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000; 92:1229–1236. PMID: 10781266
  5. 2010 Oct;113(4):873-9. A two-handed jaw-thrust technique is superior to the one-handed “EC-clamp” technique for mask ventilation in the apneic unconscious person.  Joffe et al. PMID: 20808210
  6. J Clin Anesth. 2013 May;25(3):193-7. Efficacy of facemask ventilation techniques in novice providers.  Gerstein et al.   PMID: 23523573

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