Clinical pilot study of different hand positions during manual chest compressions monitored with capnography

Optimal hand position for chest compressions during cardiopulmonary resuscitation is unknown. Recent imaging studies indicate significant inter-individual anatomical variations, which might cause varying haemodynamic responses with standard chest compressions. This prospective clinical pilot study intended to assess the feasibility of utilizing capnography to optimize chest compressions and identify the optimal hand position.

Intubated cardiac arrest patients treated by the physician manned ambulance between February and December 2011 monitored with continuous end-tidal CO2 (EtCO2) measurements were included. One minute of chest compressions at the inter-nipple line (INL) optimized using EtCO2 feedback, was followed by four 30-s intervals with compressions at four different sites; INL, 2 cm below the INL, 2 cm below and to the left of INL and 2 cm below and to the right of INL.

Thirty patients were included. At the end of each 30-s interval median (range) EtCO2 was 3.1 kPa (0.7-8.7 kPa) at INL, 3.5 kPa (0.5-10.7) 2 cm below INL, 3.5 kPa (0.5-10.3 kPa) 2 cm below and to the left of INL, and 3.8 kPa (0.4-8.8 kPa) 2 cm below and to the right of INL (p=0.4). The EtCO2 difference within each subject between hand positions with maximum and minimum values varied between individuals from 0.2 to 3.4 kPa (median 0.9 kPa).

Monitoring and optimizing chest compressions using capnography was feasible. We could not demonstrate one superior hand position, but inter-individual differences suggest optimal hand position might vary significantly among patients.