Pediatric Critical Care Medicine | Physiologic Stability Index (PSI)

Description

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)))

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Description

Specialty

Objective

ICD-10

Physiologic Stability Index (PSI)

Purpose: To assess the severity of acute illness for patients in the pediatric ICU.

Description

Specialty

Objective

ICD-10