The Science Journal of the American Association for Respiratory Care

2006 OPEN FORUM Abstracts

CAN PATIENT SUBJECTIVE RATINGS OF BREATHLESSNESS PREDICT EMERGENCY DEPATMENT DEPARTURE STATUS?

Amanda Saracino (medical student, Monash University, Melbourne), Andrew Dent (MBBS, MPH, FRCS(Eng), SRCS(Glas), FACEM., St Vincent's Health Melbourne), Brian Jolly (BSc(Hons), MA(Ed), PhD, Monash University, Melbourne), Tracey Weiland (BBSc(Hons.), PhD, St Vincent's Health Melbourne).

Background: Rapid severity assessments of patients presenting to the emergency department (ED) with shortness of breath (SOB) are vital and can facilitate patient prioritisation and quick, accurate site of care decisions. Since SOB cannot be directly measured, patient verbal subjective ratings of breathlessness may represent a simple and useful strategy for this. This study investigated the validity of a verbal rating scale for SOB and tested its ability to predict ED departure status for patients presenting with breathlessness.

Methods: This prospective observational study was conducted in two parts at a tertiary hospital; (1) Tool validation, (2) Predicting departure status (1) A convenience sample of patients presenting for cardiac stress tests was used. Objective and subjective breathlessness parameters were collected before, at 3 minutely intervals during and at cessation of exercise, and following a 2.5 minute post-exercise recovery period. Parameters included respiratory rate (RR), oxygen saturation (SaO2), heart rate (HR), systolic blood pressure (SBP) and verbal scores for present dyspnea (VDS); "On a scale from 0 to 10, how short of breath do you feel, with zero being no SOB and ten the worst SOB you could ever imagine?" (2) A random sample of patients presenting to the ED with SOB was used and subjective and objective breathlessness parameters were collected at initial presentation and thirty-minutes later. Breathlessness parameters included those considered for tool validation, plus VDS for the worst SOB during the current episode. Primary endpoints were departure status (home, emergency observation unit, ward) and length of hospital stay (LOS).

Results: (1) The validation cohort included 48 participants. Within-subject Spearman correlation co-efficients (r) were calculated using an average of 6 data points for each participant. VDS increased progressively during exercise (table one) and correlated significantly with RR (mean r=0.95, standard deviation (SD) 0.07), HR (mean r=0.90, SD 0.11) and SBP (mean r=0.95, SD 0.06). SaO2 was not significantly correlated.

  Baseline 3mins 6mins 9mins 12mins Cessation Recovery
Dyspnea score 0.1(0.4) 2.5(1.8) 4.4(2.1) 5.2(2.1) 6.3(2.2) 8.1(1.5) 4.0(1.9)
RR 16(3.2) 21(3.9) 26(5.1) 29(4.2) 35(4.7) 34(5.4) 24(3.4)
HR 74(10.9) 113(19.4) 129(20.0) 145(18.4) 149(19.1) 154(23.6) 105(14.5)
SBP 132(14.5) 143(16.7) 153(18.5) 159(21.8) 160(20.1) 162(19.0) N/A
SaO2 98(0.7) 97(0.7) 97(1.0) 97(0.7) 97(0.7) 96(1.1) N/A


Table 1: Mean (SD) of all breathlessness measures at recorded time points

(2) The ability of all independent variables to predict departure status was tested using stepwise regression. VDS at initial presentation and age were significant predictors of departure status (p < 0.001, 80% correct classification). VDS at initial presentation for present and worst dyspnea were the strongest correlates with LOS (r=0.388, p<0.001 and r=0.405, p<0.001 respectively).

Conclusion: A verbal numerical SOB rating scale is valid and as a predictor of emergency department departure status may represent a useful strategy to assist with rapid urgency assessments and site of care decision making in the ED. Further expanded studies are required before such a tool can become a routine part of the emergency evaluation of SOB.

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