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.