Asthmatic patients coming to the Emergency Room in an acute asthmatic attack can be quickly identified for risk of poor response to treatment by looking at the peak expiratory flow rate at 30 minutes.
Patient selection:
(1) Adults 18 to 50 years of age presenting to a tertiary medical center in Montevideo, Uruguay.
(2) PEFR or FEV1 < 35% of predicted
(3) no history of chronic cough
(4) no history of cardiac, hepatic, renal or other medical conditions.
Treatment:
(1) Salbutamol was administered by metered-dose inhaler into a spacer device in 4 puffs actuated at 10 minute intervals.
(2) Response was indicated by FEV1 at 3 hours, with good response > 45% of predicted and poor response <= 45% of predicted.
(3) Patients with poor response after 3 hours received 500 mg hydrocortisone IV.
Equations for Predicting PEF from Nunn (1989)
Peak expiratory flow for men:
LN(PEF in L/min) =
= (0.544 * LN(age in years)) - (0.0151 * (age in years)) - (74.7 / (height in cm)) + 5.48
Peak expiratory flow for women:
LN(PEF in L/min) =
= (0.376 * LN(age in years)) - (0.0120 * (age in years)) - (58.8 / (height in cm)) + 5.63
Bedside Index
|
Parameter |
Finding |
Score |
|
PEFR at 30 minutes as percent of predicted PEFR |
>= 50 |
0 |
|
|
40 - 49 |
1 |
|
|
< 40 |
2 |
|
change in PEFR in L/min from baseline at 30 minutes |
>= 90 |
0 |
|
|
60 - 89 |
1 |
|
|
< 60 |
2 |
bedside index =
= (points for percent of predicted PEFR at 30 minutes) + (points for change in PEFR at 30 minutes)
Interpretation:
• minimum score: 0
• maximum score: 4
|
Bedside Index |
Percent with FEV1 > 45% at 3 hours |
Percent with FEV1 <= 45% at 3 hours |
|
0 |
100% |
0% |
|
1 |
90% |
10% |
|
2 |
63% |
37% |
|
3 |
82% |
18% |
|
4 |
6% |
94% |
Specialty: Pulmonology
