Evaluation of the Neonatal Resuscitation Program's recommended chest compression depth using computerized tomography imaging☆
Received 14 July 2009; received in revised form 23 December 2009; accepted 29 January 2010. published online 11 March 2010.
Abstract
Background
Neonatal Resuscitation Program (NRP) guidelines recommend chest compression depths of 1/3 the anterior–posterior (AP) chest depth. Appropriateness of this recommendation has not been rigorously assessed.
Objective
To compare the efficacy and safety of neonatal chest compression depths of 1/4, 1/3, and 1/2 AP chest depth during cardiopulmonary resuscitation.
Design/methods
Anterior–posterior internal and external chest depth, heart dimensions, and non-cardiac thoracic tissue depth were measured from neonatal chest CTs. Using these measurements, residual internal chest depth, the remaining depth of the chest between the sternum and spine after external compression, was calculated for compression depths of 1/4, 1/3 and 1/2 anterior–posterior chest depth. Compression sufficient to compress the chest to <10mm of residual internal chest depth was defined as over-compression. Using a mathematic model, an estimated ejection fraction (EF) was calculated for each chest compression depth. Compression inadequate to obtain a predicted 50% EF was defined as under-compression. Descriptive statistics, Fisher's exact test and Student's t-test were used to analyze data, where appropriate.
Results
Fifty-four neonatal chest CT scans were evaluated. Estimated chest compression induced EF increased incrementally with increasing chest compression depth (EF was 51±3% with 1/4 AP chest depth vs 69±3% with 1/3 AP chest depth, and 106% with 1/2 AP chest depth, p<0.001). Under-compression was predicted in 29/54 patients with 1/4 AP compression depth, but none of the patients with 1/3 or 1/2 AP compression depth, p<0.001. Over-compression, or lack of adequate residual chest depth, was predicted in 49/54 patients with 1/2 AP compression depth, but none of the patients with 1/4 or 1/3 AP compression depth, p<0.001.
Conclusions
Mathematical modeling based upon neonatal chest CT scan dimensions suggests that current NRP chest compression recommendations of 1/3 AP chest depth should be more effective than 1/4 compression depth, and safer than 1/2 AP compression depth.
aChildren's Hospital of Philadelphia, Department of Neonatology, United States
bThe Children's Hospital of Philadelphia, Department of Anesthesia, Critical Care Medicine, and Pediatrics, University of Pennsylvania School of Medicine, United States
cChildren's Hospital of Philadelphia, Department of Radiology, United States
dPurdue University, Department of Biomedical Engineering, United States
eChildren's Hospital of Philadelphia, Department of Anesthesiology and Critical Care Medicine, United States
fChildren's Hospital at Dartmouth, Department of Pediatric Critical Care, United States
gChildren's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania School of Medicine, United States
Corresponding author at: Crozer-Chester Medical Center, Neonatology, One Medical Center Blvd., Upland, PA 19013, United States. Tel.: +1 610 724 8066.
ABSTRACT