Optimization of Blood Pressure Management with Vasoactive Medications using Horizon Trends

Background:  The management of blood pressure using vasopressor therapy is routine practice in critical care. Current monitoring systems rely on audible alarms which trigger when the patient’s blood pressure drops below desired threshold. This results in undesirable fluctuations in blood pressure, which can lead to cardiac ischemia.  
Purpose: The purpose of this study was to describe the practice of vasopressor titration in a group of critically ill patients using three bedside displays: Group 1 (standard audible alarm), Group 2 (Horizon Trend for BP compliance), and Group 3 (Horizon Trend and ST Map for cardiac ischemia). 
Methods:  A total of 74 critically ill patients receiving titrating vasoactive medications for blood pressure support were used as study participants. Group 1 (N=30) used audible alarms for blood pressure management.  Group 2 (N=21) used Horizon Trends in addition to the audible alarms. Group 3 (N=23) used both horizons and ST Map on the resting display. Information provided by this display was used to manage both the blood pressure and any ST segment changes in conjunction with the standard display. 
Continuous blood pressure measurements were recorded electronically using a laptop computer attached to the monitoring system, yielding over 4000 hours of continuously collected data.
Results:  

	Mean BP	% of time at or above 65mmHg	ST segments
Group 1 (n=30)	68.1 (6.8)	63.7 (25.3)	No differences across the groups
Group 2 (n=21)	70.9 (7.2)	71.1 (21.6)
Group 3 (n=23)	74.7 (6.4) p=.001	81.1 (20.5) p=.009

Table 1: Comparison of MAP and % of time spent within the target BP range while on vasopressors between all three study groups.  Significance is between groups 1 & 3.
Conclusions: Subjects in both the Horizon Trends group (Group 2) and the Horizon Trends/ST Map group (Group 3) had higher mean arterial blood pressures and spent more time within their target blood pressure ranges as compared to Group 1.   These differences were significant between Group 3 and Group 1.  No differences were found in the ST segments across the three groups. 
Discussion: Horizon Trends and ST Map display the data in a way that appears to improve clinical practice.  Further study regarding the impact this has on cardiac ischemia needs further study.