Effect of chest compressions only during experimental basic life support on alveolar collapse and recruitment.
OBJECTIVE
The importance of ventilatory support during cardiac arrest and basic life support is controversial. This experimental study used dynamic computed tomography (CT) to assess the effects of chest compressions only during cardiopulmonary resuscitation (CCO-CPR) on alveolar recruitment and haemodynamic parameters in porcine model of ventricular fibrillation.


METHODS
Twelve anaesthetized pigs (26+/-1 kg) were randomly assigned to one of the following groups: (1) intermittent positive pressure ventilation (IPPV) both during basic life support and advanced cardiac life support, or (2) CCO during basic life support and IPPV during advanced cardiac life support. Measurements were acquired at baseline prior to cardiac arrest, during basic life support, during advanced life support, and after return of spontaneous circulation (ROSC), as follows: dynamic CT series, arterial and central venous pressures, blood gases, and regional organ blood flow. The ventilated and atelectatic lung area was quantified from dynamic CT images. Differences between groups were analyzed using the Kruskal-Wallis test, and a p<0.05 was considered statistically significant.


RESULTS
IPPV was associated with cyclic alveolar recruitment and de-recruitment. Compared with controls, the CCO-CPR group had a significantly larger mean fractional area of atelectasis (p=0.009), and significantly lower PaO2 (p=0.002) and mean arterial pressure (p=0.023). The increase in mean atelectatic lung area observed during basic life support in the CCO-CPR group remained clinically relevant throughout the subsequent advanced cardiac life support period and following ROSC, and was associated with prolonged impaired haemodynamics. No inter-group differences in myocardial and cerebral blood flow were observed.


CONCLUSIONS
A lack of ventilation during basic life support is associated with excessive atelectasis, arterial hypoxaemia and compromised CPR haemodynamics. Moreover, these detrimental effects remain evident even after restoration of IPPV.
Markstaller
Klaus
K
Department of Anaesthesiology, Johannes Gutenberg University Mainz, Langenbeckstr, Mainz, Germany. markstaller@gmx.com
Rudolph
Annette
A
Karmrodt
Jens
J
Gervais
Hendrik W
HW
Goetz
Rolf
R
Becher
Anja
A
David
Matthias
M
Kempski
Oliver S
OS
Kauczor
Hans-Ulrich
HU
Dick
Wolfgang F
WF
Eberle
Balthasar
B
D000818:Animals; D001784:Blood Gas Analysis; D004195:Disease Models, Animal; D006336:Heart Massage / Q000379:methods*; D006439:Hemodynamics; D008020:Life Support Care; D008863:Microspheres; D011650:Pulmonary Alveoli / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011659:Pulmonary Gas Exchange; D012039:Regional Blood Flow; D013552:Swine; D014057:Tomography, X-Ray Computed; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy*