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PubMed2002

Inspiratory impedance threshold valve during CPR.

The use of an inspiratory impedance threshold valve (ITV) during cardiopulmonary resuscitation (CPR) should reduce intrathoracic pressure during natural chest recoil or active chest decompression. This might in turn improve venous return and thereby organ blood flow. The haemodynamic effects during both standard CPR and active compression-decompression (ACD)-CPR with and without the ITV, therefore, were studied in a well-established porcine model with cross-over design. Sixteen pigs were randomised to one of four methods initially, changing the method every fifth minute during mechanical chest compression at 100 min(-1). Myocardial blood flow was doubled when the valve was added to standard CPR, median (q25-q75) 14 (3-47) versus 27 (9-51) ml min(-1) 100 g(-1) (P=0.001). ACD-CPR caused a similar increase, while adding the ITV to ACD-CPR only tended to increase myocardial blood flow (P=0.077). Varying the technique had no effect on cerebral, kidney or carotid blood flow, coronary perfusion pressure, expired CO(2) concentrations or blood gases. The valve is a promising new tool in CPR, but more independent studies of the device are needed.

Analysis of Variance↗

PubMed2002

Retention of basic life support skills 6 months after training with an automated voice advisory manikin system without instructor involvement.

AIM: To evaluate the retention of skills 6 months after training in ventilation and chest compressions (CPR) on a manikin with computer based on-line voice advisory feedback and the possible effects of initial overtraining. METHODS: Thirty five volunteers had 20 min provisional CPR training on a manikin with computer based voice advisory feedback but without an instructor. The appropriate feedback was taken from a pre-recorded list depending on performance measured by the manikin--computer system versus set limits for ventilation and compression variables. One group in addition was randomised to receive 10 similar 3 min training sessions during 1 week in the following month (overtrained group). All ventilation and compression variables were measured without feedback before and after the initial training session, with feedback immediately thereafter, and both without and with feedback 6 months after the initial training session. RESULTS: The initial training improved all variables. Compressions with correct depth increased from a mean of 33 to 77%, and correct inflations from a mean of 9 to 58%. After 6 months, the results for the controls were not significantly different from pre-training, except for a higher of correct inflations (18%), while the overtrained group had better retention of skills including the correct compression depth (mean 61%) and inflations (mean 42%). When verbal feedback was added both the compressions and ventilations immediately improved both when tested immediately and 6 months after the initial training session. CONCLUSIONS: The computer-based voice advisory manikin (VAM) feedback system can improve immediate performance of basic life support (BLS) skills, with better long-term retention with overtraining.

Adult↗