This medical study features a photo that either clarifies matters or confuses them:
“A novel method to decrease mattress compression during CPR using a mattress compression cover and a vacuum pump,” Jaehoon Oh, Youngjoon Chee, Yeongtak Song, Taeho Lim, Hyunggoo Kang, Youngsuk Cho, Resuscitation, epub 2012. The authors, at Hanyang University in Seoul and at the University of Ulsan, South Korea, explain:
“Mattress compression causes feedback devices to over-estimate the chest compression depth measurement during CPR. We propose a novel method to decrease the mattress compression using a vinyl cover. This mattress compression cover encloses the foam mattress and is compressed by a vacuum pump immediately prior to performing CPR….
“The mattress compression cover was originally designed for home use to reduce the volume of blankets for long-term storage. After putting a blanket into the vinyl bag, a vacuum cleaner was used to remove the air from the bag through a one-way valve, as shown in Figure 1. The volume of the blanket was decreased to save space during storage. Using a vacuum cleaner (Vegas 202 INOX, max air flow 210 m3/h, 1100 Watt, Soteco, Italy) as a pump, the deflation was complete within 5 seconds.”
(Thanks to investigator Ivan Oransky for bringing this to our attention.)
BONUS: An earlier study about the general subject:
“Do different mattresses affect the quality of cardiopulmonary resuscitation?” Gavin D. Perkins, Robert Benny, Simon Giles, Fang Gao, Michael J. Tweed, Intensive Care Medicine, December 2003, Volume 29, Issue 12, pp 2330-2335. The authors, at Birmingham Heartlands Hospital and at the University of Warwick, UK, conclude that:
“Resuscitation performance is adversely affected when performed on a bed (irrespective of mattress type) compared to the floor. There were no differences between the inflated and deflated mattresses, although the deflation process did not adversely affect performance. This study does not support the routine deflation of an inflated mattress during resuscitation and questions the potential benefits from using a backboard.”