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The Journal of Emergency Medicine, Vol. 30, No. 1, pp. 97–98, 2006Copyright © 2006 Elsevier Inc.

Printed in the USA. All rights reserved0736-4679/06 $–see front matter

Editorial

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BAG VS. MACHINE: WHERE ARE THEATA?

here are a variety of reasons why a patient in themergency Department (ED) requires assisted ventila-

ion. Indeed, in critical situations over 30% of the resus-itation attempt is spent on assisted ventilation (1). Theost common initial form of ventilatory assistance in

hese clinical settings is usually accomplished using theag-valve ventilation (BVV) technique. The BVV maskas developed in 1955 by Henning Ruben in Denmark

nd has been the most common method of ventilating aatient in respiratory or cardiac arrest since that time (2).ag-valve devices, consisting of a self-inflating bag andon-rebreathing valve, may be used with a mask orndotracheal tube.

BVV assistance utilizing a facemask is acceptedorldwide and considered standard of care in a variety of

linical settings (3,4). Even though BVV has been usedor decades in emergency settings and generally consid-red to be safe and effective as a method of oxygenatingnd ventilating patients, it has some potentially fatalomplications. Among them are decreased oxygenationeading to anoxic encephalopathy, lung aspiration due toastric dilatation, or even gastric rupture (5). Of partic-lar importance, gastric over-distention, aspiration ofastric contents, and barotrauma can lead to the prema-ure death of a patient (6). By exerting pressure whileentilating, the rescuer can overcome the lower esopha-eal sphincter pressure and iatrogenically produce aspi-ation (7).

In this issue of The Journal of Emergency Medicine,on Goedecke and coworkers compare facemask BVVith a resuscitation ventilator (8). In their study trying torove the advantages of a mechanical device, 40 patientsere enrolled in a cross-over design. Measurements of

irway pressures, oxygenation, and derived values werebtained. No patient in either group presented clinicallyetectable stomach insufflation. However, when com-ared with the resuscitation ventilator, the BVV with aask resulted in significantly higher peak airway pres-

ures and delta airway pressures and a much lower ox-gen saturation. These results would suggest that a re-uscitation ventilator produces less barotrauma and has

ess of a risk for inducing aspiration of gastric contents. d

97

Using a resuscitation ventilator allows the clinician tochieve higher and constant oxygen saturation levels,nd simultaneously decrease the peak airway pressurend the delta airway pressure, as well as the peak in-piratory flow rate, than when using BVV. By decreasinghese pressures, the intrathoracic pressure remains rea-onable and it may prevent gastric dilatation or aspirationue to surpassing lower esophageal sphincter pressure.

These differences between BVV and resuscitation ven-ilation have been previously studied to some extent. Noor-ergraaf and coworkers evaluated the feasibility of firstesponders providing ventilation of patients employingVV and two oxygen-driven resuscitators (3). In their

tudy, data from 104 cases were suitable for analysis. Thetudy was a controlled, prospective, blinded study using aandom selection of ASA I–II patients admitted for electiveurgery under general anaesthesia. The purpose of the studyas to evaluate gastric insufflation with a BVV mask in

omparison to a commercially available resuscitation ven-ilator, in first responders. Using the BVV with a mask, therst responders were able to ventilate the lungs in less than0% of cases. Although up to 23% of airway managementould not be provided by ventilation with the bag-valveevice, these same patients all had adequate airway man-gement using an oxygen resuscitator. Decreased gastricnsufflation was noted when the oxygen-driven apparatusas used (3).But the question of Bag or Machine remains unan-

wered. To answer this difficult question, the reader mustnterpret the data carefully. As with any other technolog-cal device, the potential for failure as it relates to itsomponents can be a disaster. For resuscitation ventila-ion usage, multiple aspects should be taken into account:ortability, availability, maintenance and cost-benefit re-ations. Resuscitator ventilators are not widely used inD settings and can be expensive, require maintenancend a certain level of training in their use. As in any otherechnology applied to the clinical arena, the level ofraining required to use these devices depends on theodel used.BVV is, and will probably continue to be the most

imple and frequently used strategy in many medicalopulations, largely because clinicians feel comfortableith this method of assisted ventilation (9,10). These

isposable units can provide powerful ventilation capa-

butam

1

98 Bag vs. Machine

ility at any time, anywhere. So, whether we choose tose the bag or the machine, we must always be aware ofhe individual patient situation and our medical criterias well as the potential risks and complications of eachethod.

Joseph Varon, MD, FACP, FCCP, FCCM

University of Texas Health Science Center-HoustonSt. Luke’s Episcopal Hospital

Houston, Texas

Jaime Aburto, MD

School of MedicineUniversidad de Monterrey

Monterrey, México

doi:10.1016/j.jemermed.2005.11.016

REFERENCES

1. von Goedecke A, Bowden K, Wenzel V, Keller C, Gabrielli A.Effects of decreasing inspiratory times during simulated bag-valve-

mask ventilation. Resuscitation 2005;64:321–5.

2. Ruben H. A new non-rebreathing valve. Anesthesiology 1995;16:643–5.

3. Noordergraaf GJ, van Dun PJ, Kramer BP, Schors MP, HornmanHP, de Jong W. Airway management by first responders whenusing a bag-valve device and two oxygen-driven resuscitators in104 patients. Eur J Anaesthesiol 2004;21:361–6.

4. Dorges V, Knacke P, Gerlach K. Comparison of different airwaymanagement strategies to ventilate apneic, nonpreoxygenated pa-tients. Crit Care Med 2003;31:800–4.

5. Smally AJ, Ross MJ, Huot CP. Gastric rupture following bag-valve-mask ventilation. J Emerg Med 2002;22:27–9.

6. Wenzel V, Idris AH, Banner MJ, et al. Respiratory system com-pliance decreases after cardiopulmonary resuscitation and stomachinflation: impact of large and small tidal volumes on calculatedpeak airway pressure. Resuscitation 1998;38:113–8.

7. Zecha-Stallinger A, Wenzel V, Wagner-Berger HG, von GoedeckeA, Lindner KH, Hormann C. A strategy to optimize the perfor-mance of the mouth-to-bag resuscitator using small tidal volumes:effects on lung and gastric ventilation in a bench model of anunprotected airway. Resuscitation 2004;61:69–74.

8. von Goedecke A, Wenzel V, Hormann C, et al. Effects of facemask ventilation in apneic patients with a resuscitation ventilator incomparison with a bag-valve-mask. J Emerg Med 2006;30:63–7.

9. Wagner-Berger HG, Wenzel V, Stallinger A, et al. Optimizingbag-valve-mask ventilation with a new mouth-to-bag resuscitator.Resuscitation 2003;56:191–8.

0. Ocker H, Hagelberg S, Idris AH, Schumacker P. Smaller tidalvolumes with room-air are not sufficient to ensure adequate oxy-genation during bag-valve-mask ventilation. Resuscitation 2000;

44:37–41.