Comparison of different flow-reducing bag-valve ventilation devices regarding respiratory mechanics and gastric inflation in an unprotected airway model

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• 作者：Fabienne C. Rabus ; Heinz-Theo Luebbers ; Klaus W. Graetz ; Till S. Mutzbauer
• 关键词：Tidal volume ; Gastric inflation ; Bag-valve-mask ventilation ; Pressure-flow reduction ; Unprotected airway ; Basic life support
• 刊名：Resuscitation
• 出版年：2008
• 出版时间：August 2008
• 年：2008
• 卷：78
• 期：2
• 页码：224-229
• 全文大小：698 K

文摘

Summary

Objective

Gastric inflation (GI) is a significant issue when ventilation is performed on unprotected airways.

Design

Experimental analysis on the respiratory effects of hose extended bag-valve ventilation devices designed to reduce inspiratory pressure and flow.

Setting

Laboratory with lung/oesophageal sphincter simulator and pressure-flow-volume analyser. Lung compliance: 300 ml/kPa, airway resistance: 0.5 kPa/l/s. Lower oesophageal sphincter pressure (LOSP): 0.5 kPa.

Interventions

Bag-valve ventilation of lung simulator. Twelve academic dental staff members used four devices: Ambu^® Mark III attached to either a reservoir bag (R) or a pressure relief valve (SV), SMART BAG^® (SB), and Easy Grip^® (EG) as control.

Results

After Bonferroni correction (p-level of significance 0.0083) for multiple comparisons, no evidence of difference between inspiratory tidal volumes (TVIN) administered by use of R (median 137 ml) and SB (149 ml) was found. Differences in TVIN were only detected between R and SV (188 ml) (p = 0.002). Only a trend towards TVIN differences between SB and R in comparison to EG (195 ml) was found (p = 0.009).

Distributions of peak pressures differed when R (median 0.7 kPa) and SV (1.0 kPa) (p = 0.006) or SB (0.7 kPa) and SV (p = 0.002) were compared.

Peak inspiratory flow rates differed between EG (median 59l/min) and R (32l/min) as well as SB (42 l/min) and between SB and SV (50 l/min) (all with p = 0.001).

GI was lowest by use of R (median 103 ml) compared to all other devices (EG: 518 ml, SV: 394 ml, SB: 271 ml) (p = 0.001). The areas under the pressure/flow over time curves were larger during SB compared to R ventilation.

Mean airway pressures were significantly lower by use of R (0.1 kPa) compared to SB (0.3 kPa) (p < 0.008).

Conclusion

Lowering GI by pressure-flow reduction may result in lower TV depending on the device used. Lowest GI resulted from R ventilation. This may be explained by the specific pressure/time or flow/time patterns achieved by use of this device.