The Physiologic Stability Index is an attempt to assess severity of acute illness in pediatric patients admitted to the ICU.
Physiologic Systems (7) and Variables (34)
(1) cardiovascular: systolic blood pressure, diastolic blood pressure, heart rate, cardiac index, C(a-v)O2, CVP, PCWP
(2) respiratory: respiratory rate, PaO2, PaO2/FIO2, PaCO2
(3) neurologic: Glasgow coma score, intracranial pressure, seizures, pupils
(4) hematologic: hemoglobin, WBC count, platelet count, PT/PTT, FSP
(5) renal: BUN, creatinine, urine output
(6) gastrointestinal: AST/ALT, amylase, total bilirubin, albumin
(7) metabolic: sodium, potassium, calcium, glucose, osmolality, pH, HCO3
Points for each variable:
(1) 0, 1, 3, 5
(2) reflect clinical importance of derangement, with more abnormal having higher point value
(3) not intended to reflect magnitude of deviation from the normal value
Variable |
0 Points |
1 Points |
3 Points |
5 Points |
---|---|---|---|---|
systolic blood pressure in mm Hg: infants |
66-129 |
55-65, or 130-160 |
40-54, or > 160 |
< 40 |
systolic blood pressure in mm Hg: children | 66-149 | 65-75, or 150-200 | 50-74, or > 200 | < 50 |
diastolic blood pressure, in mm Hg |
< 90 |
90-110 |
> 110 |
|
heart rate, in beats per minute: infants |
91-159 |
75-90, or 160-180 |
50-74, or 181-220 |
< 50, or > 220 |
heart rate, in beats per minute: children | 81-149 | 60-80, or 150-170 | 40-59, or 171-200 | < 40 or > 200 |
cardiac index, in L per min per square meter |
> 3.0 |
2.0-3.0 |
1.0-1.9 |
< 1.0 |
arterial to mixed venous oxygen content difference, C(a-v)O2, in ml O2 per dL (vol%) |
3.0-5.4 |
< 3.0, or 5.5-6.5 |
> 6.5 |
|
CVP, in mm Hg |
0-15 |
< 0, or > 15 |
|
|
wedge pressure, or left atrial pressure, in mm Hg |
5-14 |
< 5, or 15-25 |
> 25 |
|
respiratory rate, in breaths per minute: infants |
• < 50 |
• 50-60 |
• 61-90 |
• > 90, apnea |
respiratory rate, in breaths per minute: children | < 30 | 51-70 | 51-70 | > 70 |
PaO2, in mm Hg |
> 50 |
50-60 |
40-49 |
< 40 |
PaO2/FIO2 |
> 300 |
200-300 |
< 200 |
|
PaCO2 in mm Hg |
30-44 |
< 30, or 45-50 |
51-65 |
< 65 |
pH |
7.31-7.54 |
7.20-7.30, or 7.55-7.65 |
7.10-7.19, or > 7.65 |
< 7.10 |
Glasgow Coma Score |
> 11 |
8-11 |
5-7 |
< 5 |
intracranial pressure, in mm Hg |
< 15 |
15-20 |
21-40 |
> 40 |
seizures |
|
focal |
grand mal or status epilepticus |
|
pupils |
equal and responsive |
equal and sluggish |
unequal and sluggish |
fixed and dilated |
hemoglobin, in g/dL |
7.1-17.9 |
5.0-7.0, or 18.0-22.0 |
3.0-5.0, or 22.1-25.0 |
< 3.0 |
WBC count, per µL |
5,001 - 19,999 |
3,000-5,000, or 20,000 - 40,000 |
< 3,000, or > 40,000 |
|
platelet count, per µL |
51,000 - 999,999 |
20,000-50,000, or > 1 M |
< 20,000 |
|
PT/PTT ratio, relative to normal control PT/PTT |
<= 1.5 |
> 1.5 |
|
|
fibrin split products in µg/mL |
<= 40 |
> 40 |
|
|
BUN, in mg/dL |
< 40 |
40-100 |
> 100 |
|
creatinine, in mg/dL |
< 2.0 |
2.0-10.0 |
> 10.0 |
|
urine output, in mL per kg per hour |
> 1.0 |
0.5-1.0 |
< 0.5 |
|
AST / ALT, in IU/L |
<= 100 |
> 100 |
|
|
amylase, in U/L |
<= 500 |
> 500 |
|
|
total bilirubin, in mg/dL |
<= 3.5 |
> 3.5 |
|
|
serum albumin, in g/dL |
> 2.0 |
1.2-2.0 |
< 1.2 |
|
sodium, in mEq/L |
126-149 |
115-125, or 150-160 |
< 115, or > 160 |
|
potassium, in mEq/L |
3.6-6.4 |
3.0-3.5, or 6.5-7.5 |
2.5-2.9, or 7.6-8.0 |
< 2.5, or > 8.0 |
calcium, in mg/dL |
8.1-11.9 |
7.0-8.0, or 12.0-15.0 |
5.0=6.9, or > 15.0 |
< 5.0 |
glucose, in mg/dL |
61-249 |
40-60, or 250-400 |
20-39, or > 400 |
< 20 |
osmolality, in mOsm/L |
< 320 |
320-350 |
> 350 |
|
bicarbonate, in mEq/L |
16-32 |
< 16 or > 32 |
|
|
where:
• infants are all those under 1 year of age; children are all those older than 1 year of age
• AST/ALT is taken to be the ratio of the transaminases
• hypoosmolality does not seem be included for evaluation
physiologic stability index =
= SUM (points for each physiologic variable)
Interpretation
Index scores:
• minimum score 0
• maximum score 119
• higher scores indicate more severe disease
Scores compared:
(1) on day of admission
(2) maximum score
(3) 4-day average
(4) trend over hospital course
Trends over hospital course:
(1) decreasing indicates improvement
(2) increasing indicates worsening
(3) unchanging
probability of mortality =
= (EXP((0.277 * (4 day average PSI)) - 5.241)) / (1 + (EXP((0.277 * ( 4 day average PSI)) - 5.241)))
Purpose: To assess the severity of acute illness for patients in the pediatric ICU.
Specialty: Critical Care, Emergency Medicine
Objective: severity, prognosis, stage, differential diagnosis and mimics, red flags, disease progression
ICD-10: R57,