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Centre for Evidence-
Based Medicine

Patent Ductus Arteriosus: Clinical exam is inaccurate and imprecise in diagnosing PDA with left to right shunting in premature infants

Clinical Bottom Line

In preterm infants with birth weights 750 to 1750 grams, the clinical examination on days 3 to 7 of life is inadequate to diagnose a PDA with left to right shunting.

Citation

Davis P., Turner-Gomes S., Cunningham K., et al. Precision and Accuracy of Clinical and Radiological Signs in Premature Infants at Risk of Patent Ductus Arteriosus. Arch Pediatr Adolesc Med 1995; 149: 1136-1141.

Clinical Question

In preterm infants, what is the accuracy of the clinical examination as a diagnostic test for patent ductus arteriosus (PDA) with left to right shunting?

Search Terms

PubMed search using MeSH terms: "patent ductus arteriosus", "infant, premature" and "sensitivity and specificity"

The Study

  • The Study Patients: Infants with birth weights between 750 and 1750 gm and who were between 3 and 7 days old. Infants were enrolled from one Canadian neonatal intensive care unit.
  • Independent blind: reference standard applied regardless of test result and performed in an appropriate spectrum of patients
  • Target disorder and Gold Standard: Patent ductus arteriosus with left to right shunting. Gold standard was echocardiography.
  • Diagnostic test: Each infant was assessed independently by at least three and up to five assessors for the pulse quality, precordial activity, and cardiac murmur.

The Evidence

Clinical Sign Sensitivity Specificity + Likelihood Ratio
Increased pulse volume 43% 74% 1.6
Active Precordium 26% 85% 1.7
Cardiac Murmur 42% 87% 3.0

Positive Predictive Value
= 22% (pulse volume); 36% (precordium); 51% (murmur).

Pre-test Probability (prevalence) of PDA
= 23%.

Pre-test-odds = prevalence/(1-prevalence)
= 0.299

Likelihood ratio for the presence of PDA with all three clinical signs
= 3.7

Post-test odds
= Pre-test odds x Likelihood Ratio
= 1.106

Post-test Probability of PDA with all three clinical signs
= Post-test odds/(Post-test odds + 1)
= 53%

Likelihood ratio for the presence of PDA without any clinical sign
= 0.6

Post-test odds
= Pre-test odds x Likelihood Ratio
= 0.179

Post-test Probability of PDA without any clinical sign
= Post-test odds/(Post-test odds + 1)
= 15%

Comments

  1. Interobserver variability of the clinical signs was examined and found to be poor (weighted kappas 0.15 to 0.41)
  2. 2x2 table cannot be generated based on the published results which were averaged amongst the different assessors.
  3. See also J Paediatr Child Health 1994; 30: 406-11 which reached similar conclusions.

Appraised By

Aaron Chiu
Department of Pediatrics and Child Health
University of Manitoba; 25 January 1999
Email: chiua@cc.umanitoba.ca

Expiry Date

December 31, 2000