Computerized Pulmonary Artery Catheter Waveform Interpretation

 

Jaime Chang

HST.951

December 14, 2005

 

 

Abstract

 

The pulmonary artery catheter (PAC) has been used for decades in the diagnosis and treatment of critically ill patients, but knowledge of PAC waveform interpretation remains inadequate among physicians and nurses.  Inspired by the relative success of EKG interpretation programs, this study investigates the feasibility of computerized PAC waveform interpretation.  Clinician-provided contextual data, accompanying EKG data, and manually pre-processed waveform data were provided as input, and the ability of classifiers to recognize dangerous situations, system problems, waveform locations, and underlying patient physiology was evaluated.  The dataset consisted of 66 waveforms classified by experts, and the classifiers tested were simple logistic regression, 1-nearest neighbor, decision tree, naïve Bayes, and neural network.  Under 4-fold cross-validation, 1-nearest neighbor had the most success at classifying accurately, but the neural network had a high area under the receiver-operator curve more consistently across the four classification tasks.  All classifiers were good at identifying location.  The results of this feasibility study are encouraging and suggest that computerized PAC waveform interpretation may be useful to clinicians.

 

 

Introduction

 

Introduced into the intensive care unit (ICU) over thirty years ago, the PAC is used in the diagnosis of cardiopulmonary disturbances and for assessing and monitoring hemodynamic variables in the critically ill.  Data derived from pulmonary artery catheterization alter therapeutic decisions in about half of all insertions.^{1 2}  More than 45 million catheters have been used since 1970.³  Use of the PAC is considered routine in most critical care areas, and estimated sales of these catheters are between 1 and 2 million annually in the United States.⁴

 

Recently, however, the presumed beneficial effect of care directed by the PAC has been called into question by both retrospective reviews and prospective, randomized trials.  Connors et al. found that PAC use was associated with increased mortality and increased utilization of resources, and subgroup analyses did not reveal any patient group or investigation site for which PAC use was associated with improved outcomes.⁵  In the “Canadianâ€