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Blood flow during cardiopulmonary resuscitation with simultaneous compression and ventilation in infant pigs
I D Berkowitz1, T Chantarojanasiri, R C Koehler
1Department of Anesthesiology/Critical Care Medicine, Johns Hopkins Medical Institution, Baltimore, Maryland 21205.
Insights
Simultaneous chest compression and ventilation cardiopulmonary resuscitation (SCV-CPR) did not improve cerebral blood flow in piglets. Prolonged SCV-CPR led to chest deformation and impaired blood flow and oxygen uptake.
Area of Science:
- Cardiovascular physiology
- Pediatric resuscitation
- Critical care medicine
Background:
- Cardiopulmonary resuscitation (CPR) is a critical intervention for cardiac arrest.
- The simultaneous chest compression and ventilation (SCV) technique aims to improve CPR efficacy.
- Previous studies in adult models suggest SCV enhances blood flow, but its effect in infants is less understood.
Purpose of the Study:
- To evaluate if SCV-CPR enhances cerebral blood flow (CBF) and myocardial blood flow (MBF) in an infant swine model.
- To determine if SCV-CPR sustains CBF and MBF during prolonged CPR.
- To assess cerebral oxygen uptake during SCV-CPR in piglets.
Main Methods:
- Infant swine (3.5-5.5 kg) underwent either conventional CPR or SCV-CPR with continuous epinephrine infusion.
- CPR techniques involved specific compression rates, duty cycles, ventilation ratios, and airway pressures.
- Measurements included myocardial blood flow, cerebral blood flow, and pressures (aortic, right atrial, intracranial) over 50 minutes.
Main Results:
- At 5 minutes, SCV-CPR showed slightly higher MBF but comparable CBF compared to conventional CPR.
- Prolonged CPR (50 minutes) resulted in chest deformation and loss of sternal recoil in both groups.
- Aortic pressure declined, while CBF, MBF, and cerebral oxygen uptake were significantly impaired during prolonged CPR, irrespective of the technique.
Conclusions:
- SCV-CPR did not demonstrate enhanced CBF or sustained blood flow in this infant swine model.
- Chest deformation and reduced recoil limit the effectiveness of SCV-CPR during prolonged resuscitation.
- Further research is needed to optimize CPR techniques for pediatric patients.
Abstract:
We determined whether the simultaneous chest compression and ventilation (SCV) technique of cardiopulmonary resuscitation (CPR) enhances cerebral (CBF) and myocardial (MBF) blood flows and cerebral O2 uptake in an infant swine model of CPR as it does in most adult animal CPR models. We also tested whether SCV-CPR sustains CBF and MBF for prolonged periods of CPR when these flows ordinarily deteriorate. CPR was performed in two groups (n = 8) of pentobarbital anesthetized piglets (3.5-5.5 kg) with continuous epinephrine infusion (10 micrograms/kg/min). Conventional CPR was performed at 100 compressions/min, 60% duty cycle, 1:5 breath to compression ratio and 25-30 mm Hg peak airway pressure. SCV-CPR was performed at 60 compressions/min, 60% duty cycle and 60 mm Hg peak airway pressure applied during each chest compression. Peak right atrial and aortic pressures in excess of 80 mm Hg were generated during CPR in both groups. At 5 min of conventional and SCV-CPR, MBF was 38 +/- 7 and 46 +/- 7 mL.min-1.100 g-1 (+/- SE), respectively, and CBF was 15 +/- 3 and 13 +/- 2 mL.min1. 100 g-1, respectively. However, as CPR was prolonged to 50 min, the sternum progressively lost its recoil and the chest became more deformed. Lung inflation at high airway pressure with SCV-CPR did not prevent this chest deformation. Aortic pressure gradually declined, whereas right atrial and intracranial pressure remained constant in both groups. Consequently, MBF and CBF fell less than 10 mL.min-1.100 g-1 and cerebral O2 uptake was markedly impaired during prolonged conventional and SCV-CPR.(ABSTRACT TRUNCATED AT 250 WORDS)