Pneumonia severity index

The pneumonia severity index (PSI) or PORT Score is a clinical prediction rule that medical practitioners can use to calculate the probability of morbidity and mortality among patients with community acquired pneumonia.^[1]

Despite sometimes being used to predict the need for hospitalization in people with pneumonia,^[2] the PORT score was not developed to do so and should not be used in that way. Mortality prediction is similar to that when using CURB-65.^[3]

Development

The rule uses demographics (whether someone is older, and is male or female), the coexistence of co-morbid illnesses, findings on physical examination and vital signs, and essential laboratory findings. This study demonstrated that patients could be stratified into five risk categories, Risk Classes I-V, and that these classes could be used to predict 30-day survival.

Usage

The purpose of the PSI is to classify the severity of a patient's pneumonia to determine the amount of resources to be allocated for care. Most commonly, the PSI scoring system has been used to decide whether patients with pneumonia can be treated as outpatients or as (hospitalized) inpatients.

A Risk Class I or Risk Class II pneumonia patient can be sent home on oral antibiotics.^[4]
A Risk Class III patient, after evaluation of other factors including home environment and follow-up, may either:^[5]

be sent home with oral antibiotics^[4]
be admitted for a short hospital stay with antibiotics and monitoring.^[4]

Patients with Risk Class IV-V pneumonia patient should be hospitalized for treatment.^[4]

Algorithm

The PSI Algorithm is detailed below. An online, automated PSI calculator is available on the US AHRQ website.

Step 1: Stratify to Risk Class I vs. Risk Classes II-V
	Presence of:
		Over 50 years of age	Yes/No
		Altered mental status	Yes/No
		Pulse ≥125/minute	Yes/No
		Respiratory rate >30/minute	Yes/No
		Systolic blood pressure <90 mm Hg	Yes/No
		Temperature <35°C or ≥40°C	Yes/No
	History of:
		Neoplastic disease	Yes/No
		Congestive heart failure	Yes/No
		Cerebrovascular disease	Yes/No
		Renal disease	Yes/No
		Liver disease	Yes/No

		If any "Yes", then proceed to Step 2
		If all "No" then assign to Risk Class I

Step 2: Stratify to Risk Class II vs III vs IV vs V
	Demographics		Points Assigned
		If Male	+Age (yr)
		If Female	+Age (yr) - 10
		Nursing home resident	+10
	Comorbidity
		Neoplastic disease	+30
		Liver disease	+20
		Congestive heart failure	+10
		Cerebrovascular disease	+10
		Renal disease	+10
	Physical Exam Findings
		Altered mental status	+20
		Pulse ≥125/minute	+10
		Respiratory rate >30/minute	+20
		Systolic blood pressure <90 mm Hg	+20
		Temperature <35°C or ≥40°C	+15
	Lab and Radiographic Findings
		Arterial pH <7.35	+30
		Blood urea nitrogen ≥30 mg/dl (9 mmol/liter)	+20
		Sodium <130 mmol/liter	+20
		Glucose ≥250 mg/dl (14 mmol/liter)	+10
		Hematocrit <30%	+10
		Partial pressure of arterial O2 <60mmHg	+10
		Pleural effusion	+10

		∑ <70 = Risk Class II
		∑ 71-90 = Risk Class III
		∑ 91-130 = Risk Class IV
		∑ >130 = Risk Class V

Data source for derivation and validation

The rule was derived then validated with data from 38,000 patients from the MedisGroup Cohort Study for 1989, comprising 1 year of data from 257 hospitals across the US who used the MedisGroup patient outcome tracking software built and serviced by Mediqual Systems (Cardinal Health). One significant caveat to the data source was that patients who were discharged home or transferred from the MedisGroup hospitals could not be followed at the 30-day mark, and were therefore assumed to be "alive" at that time. Further validation was performed with the Pneumonia Patient Outcomes Research Team [PORT] (1991) cohort study. This categorization method has been replicated by others^[6] and is comparable to the CURB-65 in predicting mortality.^[6]

Derivation and validation data

	Medisgroup Study (1989)				PORT Validation Study (1991) Cohort
	Derivation Cohort		Validation Cohort		Inpatients		Outpatients		All Patients
Risk Class	no. of pts	% died	no. of pts	% died	no. of pts	% died	no. of pts	% died	no. of pts	% died
I	1,372	0.4	3,034	0.1	185	0.5	587	0.0	772	0.1
II (<70)	2,412	0.7	5,778	0.6	233	0.9	244	0.4	477	0.6
III (71–90)	2,632	2.8	6,790	2.8	254	1.2	72	0.0	326	0.9
IV (91–130)	4,697	8.5	13,104	8.2	446	9.0	40	12.5	486	9.3
V (>130)	3,086	31.1	9,333	29.2	225	27.1	1	0.0	226	27.0
Total	14,199	10.2	38,039	10.6	1343	8.0	944	0.6	2287	5.2

Note: % Died refers to 30-day mortality.

References

↑ Fine, MJ; Auble, TE; Yealy, DM; Hanusa, BH; Weissfeld, LA; Singer, DE; Coley, CM; Marrie, TJ; Kapoor, WN; et al. (Jan 1997). "A prediction rule to identify low-risk patients with community-acquired pneumonia". N Engl J Med 336 (4): 243–250. doi:10.1056/NEJM199701233360402. PMID 8995086.
↑ Mark Williams; Scott A. Flanders; Winthrop F. Whitcomb (28 September 2007). Comprehensive hospital medicine: an evidence based approach. Elsevier Health Sciences. pp. 273–. ISBN 978-1-4160-0223-9. Retrieved 11 November 2010.
↑ Chalmers JD, Singanayagam A, Akram AR, et al. (October 2010). "Severity assessment tools for predicting mortality in hospitalised patients with community-acquired pneumonia. Systematic review and meta-analysis". Thorax 65 (10): 878–83. doi:10.1136/thx.2009.133280. PMID 20729231.
1 2 3 4 Scott Kahan (1 January 2003). In a Page Medicine. Lippincott Williams & Wilkins. ISBN 978-1-4051-0325-1. Page 40
↑ "NewYork-Presbyterian Hospital Guidelines for the Empiric Management of Adult Patients with Community-Acquired Pneumonia (CAP) and IV to PO Conversion" (PDF). Last updated 05-06-10. Retrieved 2015-05-22. Check date values in: |date= (help)
1 2 Aujesky D, Auble TE, Yealy DM, et al. (2005). "Prospective comparison of three validated prediction rules for prognosis in community-acquired pneumonia". Am. J. Med. 118 (4): 384–92. doi:10.1016/j.amjmed.2005.01.006. PMID 15808136.

External links

Tests, surgery and other procedures involving the respiratory system (ICD-9-CM V3 21–22, 30–34, ICD-10-PCS 0B)

Upper RT	nose Rhinoplasty Septoplasty Rhinectomy Rhinomanometry sinus Sinusotomy larynx Laryngoscopy Laryngectomy Laryngotomy Thyrotomy

Lower RT	trachea Cricothyrotomy Tracheoesophageal puncture Tracheotomy bronchus Bronchoscopy lung Pneumonectomy Lobectomy Wedge resection Lung transplantation Decortication of lung Heart-lung transplant

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Medical imaging	Bronchography CT pulmonary angiogram High resolution CT Spiral CT Ventilation/perfusion scan

CPRs	Pneumonia severity index CURB-65

Lung function test	Body plethysmography Spirometry Bronchial challenge test Capnography Diffusion capacity

Cytology	Sputum culture Bronchoalveolar lavage

Respiratory therapy/ intubation	Mechanical ventilation Positive pressure ventilation Artificial respiration Nebulizer Hyperbaric medicine Oxygen therapy Decompression chamber Heliox Negative pressure ventilator Postural drainage CPR

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