Vital signs

Vital signs monitoring plays a crucial role in helping nurses prevent worsening clinical situations becoming crises. In order to be valuable tools, the four physiological readings (systolic blood pressure, heart rate, respiratory rate and body temperature) must be correctly measured, recorded and interpreted. Inaccurate and misinterpreted information can compromise timely interventions for deteriorating patients and have fatal results.

Solutions proposed to improve the accuracy of vital signs monitoring include the MEWS system(1). The Modified Early Warning Score takes the reading of vital signs along with a level of consciousness observation to produce a score that identifies patients at risk of deterioration. The MEWS system is an example of a track and trigger system, whereby the tracking of data results in the triggering of an action. In some circumstances, trends towards deterioration and instability may be difficult to detect and vital signs perhaps not the best indicators. Another index, called the Shock Index (SI), may be an accurate and simple alternative(2). The SI uses heart rate divided by systolic blood pressure as an indicator of left ventricular function, where the reference is 0.54. The SI has been shown to be useful in unplanned, unexpected transfers from general medical wards to ICU wards where the SI value is greater than 0.85.