Objective
To compare invasive blood pressure (BP) measurements recorded using an automated archiving method against clinician-documented values from the same invasive monitor, and determine which method of recording BP is more highly associated with the subsequent onset of hypotension.
Design
Retrospective comparative analysis.
Setting
Intensive care patients in a university hospital.
Patients
Mixed medical/surgical patients.
Interventions
N/A
Measurements
Using intervals of hemodynamic stability from 2,320 patient records, we retrospectively compared paired sources of invasive BP data: (1) measurements documented by the nursing (RN) staff; and (2) measurements generated by an automated archiving method that intelligently excludes unreliable (e.g., noisy or excessively damped) BP values. The primary outcome was the occurrence of subsequent “consensus” hypotension, i.e., hypotension documented jointly by the RN and the automated archive.
Main Results
The automated method could be adjusted to alter its operating characteristics (sensitivity and specificity). At a matched level of specificity (96%), BP from the automated archiving method was more sensitive (28%) for subsequent “consensus” hypotension versus the RN documented values (21%). Likewise, at a matched level of sensitivity (21%), the automated method was more specific (99%) versus the RN documented values (96%). These significant findings (p < 0.001) were consistent in a set of sensitivity analyses which employed alternative criteria for patient selection and the clinical outcome definition.
Conclusions
During periods of hemodynamic stability in an ICU patient population, clinician-documented BP values were inferior to an intelligent automated archiving method, as early indicators of hemodynamic instability. Human oversight may not be necessary for creating a valid archive of vital signs data within an electronic medical record. Moreover, if clinicians do have a tendency to disregard early indications of instability, then an automated archive may be a preferable source of data for so-called Early Warning Systems that identify patients at-risk of decompensation.