Load distributing band CPS

The Autopulse presents an alternative to the (high impulse) active compression-decompression devices that cryonics organizations currently employ to provide cardiopulmonary support (CPS) during stabilization. The Autopulse uses batteries instead of compressed oxygen and is easy to set up and operate. Disadvantages include its cost, limited patient size range, and the modifications that cryonics organizations must make to protect it from water during operation in a portable ice bath. But perhaps the most serious concern that has been expressed about the Autopulse (or any other mechanical CPR devices without active decompression) is that it may be less effective for patients with flail chest during extended CPS times.

The most fundamental question, however, is whether load distributing band CPR (LDB-CPR) is superior to high impulse active compression-decompression CPR (HI-ACD CPR). Some studies report impressive performance of the Autopulse in animal models but a recent randomized trial found worse neurological outcomes versus manual CPR. An editoral discussing these apparently contradictory results contains an interesting observation:

“Standard, manual CPR may be better than is generally recognized. Preclinical investigations of the LDB-CPR device typically compared it with the only commercially available mechanical CPR device, a gas drive piston-cylinder. This device compresses the sternum 1.5 to 2 inches, presumably causing cardiac compression, the other mechanism of blood flow during CPR. In preclinical comparisons, the pistoncylinder device appears to have been adjusted to produce 20% anterior-posterior sternal displacement, similar to that produced by LDB-CPR and likely to be less than an inch in 20-kg swine. This 20% value may represent the optimal performance characteristics for LDB-CPR in small swine but may have reduced the performance of the older pistoncylinder device. A comparison of LDB-CPR to “good” manual CPR in a laboratory model could prove to be revealing.”

To our knowledge, realistic head-to-head comparisons between good mechanical HI-ACD CPR and LDS-CPR, including the use of an inspiratory impedance threshold device, such as the ResQPOD, have not been published so far.