- Bag-Valve-Mask (BVM) apparatus are also known as manual resuscitators and as self-inflating resuscitation systems
- examples include LaerdalTM, AmbuTM, HsinerTM, MayoTM, and Air VivaTM
- administration of high flow O2
- provision of PEEP (positive end-expiratory pressure)
- provision of controlled ventilation
- provision of augmentation of spontaneous ventilation
- self-inflating resuscitation device
- bag made of plastic materials that re-expand after being manually collapsed
- various sizes e.g. Laerdal 240 mL, 500 mL, 1600 mL bag sizes for infants, children and adults
- oxygen inlet nipple
- air intake valve
- oxygen reservoir with two one way valves
- reservoir is at least the volume of the bag
- oxygen flow rate equal to, or higher than, the minute volume of the patient allows 100% oxygen to be delivered
- inlet valve allows room air to enter if fresh gas flow is inadequate and an outlet valve allow oxygen to flow out if pressure is excessive
- non-rebreathing valve that directs fresh flow of oxygen to the patient and prevents exhaled gas re-entering the bag
- standard 15 mm adapter for attaching to masks or tubes
- able to attach PEEP valve to exhalation port (either “built in” or detachable)
- can hold down pop off valve (releases at about 60 cmH2O) to give increased pressure in the circuit
- Masks come in a range of sizes and designs
- opaque or clear plastic
- firm or air inflated cushion
- mouldings vary but are designed to minimise dead space and fit
- some have specific names (e.g. Rendall Baker Mask for paediatrics)
METHOD OF INSERTION AND/OR USE
- High flow oxygen (e.g. 15 L/min) is attached to the system and it is attached to a mask or tube
- appropriate mask size
- place over mouth and nose
- tight fit
- open airway using two-handed thumbs down technique (with an assistant bagging) in preference to the less effective one-handed C-E grip to ensure airway patency (best if OPA and NPAs in situ too)
- the bag is used to deliver oxygen to a spontaneously breathing patient or the bag compressed to manually ventilate them via a mask or tube (an assistant can provide ventilations)
Remember JAWS for the two-handed two-thumbs down two person technique:
- Jaw thrust
- Airways (oral/nasal)
- Work together
- Slow, small squeeze — 6-7 cc/kg, over 1-2 seconds, at <12/min, using low pressure.
- easy to hyperventilate patients and limited ability to gauge tidal volumes
- unable to gauge lung compliance (cf. a ventilator or Water’s circuit)
- poor seal is common if one-handed CE grip is used
- gastric distension
- exhaled secretions and moisture can result in exhalation valve dysfunction and increased resistance to expiration
- risk of barotrauma if pop off valve close as unable to feel lung compliance with self-inflating bags
- if high free gas flows are not used high FiO2 will not be achieved
- equipment failure (e.g. due to incorrect assembly)
- Adminstered FiO2 during spontaneous ventilation can vary greatly between devices
- Laerdal: FiO2 0.96
- Hsiner: FiO2 0.75
- Mayo: FiO2 0.55
- sufficient negative inspiratory pressure is required to overcome the patient inspiratory valve, otherwise, air will be entrained instead of oxygen
- some duckbill valves are difficult to overcome when spontaneously breathing
- patients with reduced respiratory effort are particularly at risk
- As a safeguard in spontaneously breathing patients it is useful to coordinate ‘assist’ positive pressure ventilation with the patient’s spontaneous efforts to ensure that the patient inspiratory valve is opening
- If the patient is edentulous, then adjust the position of the mask like so:
Fom Racine SX, et al (2010), image from EM Updates (click image for source)
Alternatives to BVM
- use a ventilator to provide non-invasive ventilation
- use of a Mapleson C (Waters circuit)
- in paediatrics, use of Mapleson E (Jackson-Ress modification of the Ayre’s T-pieces)
References and Links
- El-Orbany M, Woehlck HJ. Difficult mask ventilation. Anesth Analg. 2009 Dec;109(6):1870-80. PMID: 19923516
- Gerstein NS, Carey MC, Braude DA, Tawil I, Petersen TR, Deriy L, Anderson MS. Efficacy of facemask ventilation techniques in novice providers. J Clin Anesth. 2013 May;25(3):193-7. PMID: 23523573.
- Hart D, Reardon R, Ward C, Miner J. Face mask ventilation: a comparison of three techniques. J Emerg Med. 2013 May;44(5):1028-33. PMID: 23473817.
- Joffe AM, Hetzel S, Liew EC. A two-handed jaw-thrust technique is superior to the one-handed “EC-clamp” technique for mask ventilation in the apneic unconscious person. Anesthesiology. 2010 Oct;113(4):873-9. PMID: 20808210.
- Khoury A, Hugonnot S, Cossus J, et al. From mouth-to-mouth to bag-valve-mask ventilation: evolution and characteristics of actual devices – a review of the literature. Biomed Res Int. 2014;2014:762053. [article]
- Racine SX, et al (2010). Face mask ventilation in edentulous patients: a comparison of mandibular groove and lower lip placement. Anesthesiology, 112 (5), 1190-3 PMID: 20395823
FOAM and web resources
- AirwayCam — Face Mask Ventilation
- EMCRIT — Wee – What the heck is a Mapleson B Circuit and Why You Probably Shouldn’t Care (2014)
- Resus.ME — Thenar Eminence Based Medicine
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.