title: Evaluation of the Neonatal Resuscitation Program's recommended chest compression depth using computerized tomography imaging.
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.
  
  
  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.
authors.affiliation: Children's Hospital of Philadelphia, Department of Neonatology, USA. andrewandsunny@yahoo.com
authors.forename: Andrew
authors.initials: A
authors.lastname: Meyer
authors.forename: Vinay
authors.initials: V
authors.lastname: Nadkarni
authors.forename: Avrum
authors.initials: A
authors.lastname: Pollock
authors.forename: Charles
authors.initials: C
authors.lastname: Babbs
authors.forename: Akira
authors.initials: A
authors.lastname: Nishisaki
authors.forename: Matthew
authors.initials: M
authors.lastname: Braga
authors.forename: Robert A
authors.initials: RA
authors.lastname: Berg
authors.forename: Anne
authors.initials: A
authors.lastname: Ades
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000379:methods / Q000592:standards; D006801:Humans; D007231:Infant, Newborn; D008955:Models, Cardiovascular; D017410:Practice Guidelines as Topic; D013902:Radiography, Thoracic; D014057:Tomography, X-Ray Computed