_id

683a1646c782e11e38d1b2fa

id

10343

title

Altitude-Adjusted PERC Rule

full_title

Altitude-Adjusted PERC Rule

short_title

Altitude-Adjusted PERC Rule

med_description

Rules out PE if no criteria are present; includes SaO2adjustment for altitude.

short_description

Rules out PE (altitude-adjusted).

slug

altitude-adjusted-perc-rule

description

The Altitude-adjusted PERC Rule for Pulmonary Embolism rules out PE if no criteria are present; includes SaO₂ adjustment for altitude.

keywords

rule out PE, rule out pulmonary embolism, VTE, PE risk, PE criteria, embolism rule out, PE calculator, perc rule, pe rule out, pulmonary embolism rule out, kline r/o, pe r/o, clinical signs pe, clinical signs r/o PE, kline dvt, perc dvt, PERC score, perc calc, perc r/o, perc rule out, pe rule out criteria, pulmonary embolism r/o, pulmonary embolism rule out criteria, PERC-Altitude Rule for Pulmonary Embolism

complaint

[ "Chest Pain", "Cough", "Shortness of Breath" ]

formula

If any of the following is/are present, PE cannot be ruled out: Age ≥50. HR ≥100. O₂ sat on room air<95%(or O₂ sat on room air<90%for high altitudes*). Unilateral leg swelling. Hemoptysis. Recent trauma or surgery. Prior PE or DVT. Hormone use (oral contraceptives, hormone replacement or estrogenic hormones use in males or female patients). *Altitudes >4000 ft.

evidence

The original PERC Rule was derived by Kline et al in 2004, but they used a hypoxemia cut off of less than 95%. The PERC Rule was validated by Wolf et al in a 2008 study performed in Denver, CO (at 5280 feet elevation). They used an oxygen saturation cut off of 90% to account for the higher elevation. Their study was relatively small and included 134 patients, 12% of whom were diagnosed with PE. Of the patients with a low pretest probability, 22% were PERC-Altitude negative, and none of them were diagnosed with a PE. The sensitivity of the PERC-Altitude Rule for the total cohort was 100%, but due to the small sample size, it has wide confidence intervals (79-100).  

In 2019, Madsen et al published a much larger, prospective, observational study of patients from Salt Lake City, UT (elevation of 4980 feet) using the same 90% oxygen saturation cutoff. They enrolled 3,024 patients who presented with chest pain and/or dyspnea. There were 58 patients diagnosed with acute PE. Using the 95% oxygen saturation cutoff from the original PERC rule (Kline 2004), the sensitivity was 96.6%. There were two patients who were PERC negative who were diagnosed with acute PE. When they used the altitude-adjusted PERC rule, 4.3% of PERC-positive patients were reclassified as PERC negative. One of the patients who was reclassified as PERC negative had an acute PE, so the sensitivity for the altitude-adjusted PERC rule was slightly less at 94.8%. They estimated that using the altitude-adjusted PERC reduced the number of CTPA scans by 2.7% compared to using the original PERC.

measurements

[]

information

refrences

{ "Clinical Practice Guidelines": [], "Manufacturer Website": [], "Original/Primary Reference": [ { "href": "https://pubmed.ncbi.nlm.nih.gov/18272098/", "text": "Wolf SJ, Mccubbin TR, Nordenholz KE, Naviaux NW, Haukoos JS. Assessment of the pulmonary embolism rule-out criteria rule for evaluation of suspected pulmonary embolism in the emergency department. Am J Emerg Med. 2008;26(2):181-5." } ], "Other References": [ { "href": "https://www.ncbi.nlm.nih.gov/pubmed/15304025", "text": "Kline JA, et al. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2004; 2: 1247–55." }, { "href": "https://www.ncbi.nlm.nih.gov/pubmed/18318689", "text": "Kline JA, et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. J Thromb Haemost 2008; 6: 772–80." } ], "Outcomes": [], "Validation": [ { "href": "https://www.ajemjournal.com/article/S0735-6757(18)30429-7/fulltext", "text": "Madsen T, Jedick R, Teeples T, Carlson M, Steenblik J. Impact of altitude-adjusted hypoxia on the Pulmonary Embolism Rule-out Criteria. Am J Emerg Med. 2019;37(2):281-285." } ], "Validations": [] }

pearls

• Most importantly this differs from the original PERC rule in that it is intended for use at high altitude (>4000 ft) and includes an O₂ cutoff of 90% as opposed to 95%.

• This tool is only meant for patients who are low risk of a PE (<15%, based on Wells' Score or clinician gestalt).

• An inexperienced clinician may underestimate the pre-test probability of a PE and use this tool inappropriately.

• This version of the PERC Rule should not be used for patients who live at low altitudes.

usecase

• In patients who present to the emergency department with chest pain or dyspnea and have a low pre-test probability for PE. 

• A negative PERC-Altitude means PE can be ruled out and does not require further work-up (D-dimer or CTPA).

• This test is for patients who live at high altitude (>4000 ft). Use the original PERC Rule for patients who live at low altitudes.

reasons

A patient with low pre-test probability for PE (<15%) and a negative PERC-Altitude test does not need D-dimer or CTPA. Can help reduce overtesting.

next_advice

next_actions

next_management

• If your patient is low risk for PE and PERC-Altitude negative, then you can rule out PE without further testing.

• If your patient is PERC-Altitude positive, further testing (D-dimer or CTPA) is required to rule out PE.

diseases

[ "Deep Venous Thrombosis", "Pulmonary Embolism" ]

input_schema

[ { "conditionality": "", "default": null, "label_en": "High altitude (>4000 ft)", "md_calc_info_concept": null, "name": "altitude", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "altitude==0", "default": null, "label_en": "O₂ sat on room air <strong><95%</strong>", "md_calc_info_concept": null, "name": "lowo2", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "altitude==1", "default": null, "label_en": "O₂ sat on room air <strong><90%</strong>", "md_calc_info_concept": null, "name": "higho2", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Age ≥50", "md_calc_info_concept": null, "name": "age", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "HR ≥100", "md_calc_info_concept": null, "name": "hr", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Unilateral leg swelling", "md_calc_info_concept": null, "name": "leg_swelling", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Hemoptysis", "md_calc_info_concept": null, "name": "hemoptysis", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Recent surgery or trauma", "md_calc_info_concept": null, "name": "trauma", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "Surgery or trauma ≤4 weeks ago requiring treatment with general anesthesia", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Prior PE or DVT", "md_calc_info_concept": null, "name": "dvt_pe_history", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "", "type": "toggle" }, { "conditionality": "", "default": 0, "label_en": "Hormone use", "md_calc_info_concept": null, "name": "estrogen", "option_fhir_rules": null, "optional": false, "options": [ { "label": "No", "value": 0 }, { "label": "Yes", "value": 1 } ], "show_points": false, "tips_en": "Oral contraceptives, hormone replacement or estrogenic hormones use in males or female patients", "type": "toggle" } ]

instructions

This tool is intended for patients with low risk for PE and who live at high altitude (>4000 ft). 

published

2022-04-21T20:28:48.675Z

purpose

[ "Diagnosis", "Rule Out" ]

search_terms

[ "pe", "pulmonary embolism", "dvt", "PERC-Altitude Rule for Pulmonary Embolism", "perc rule", "perc", "perc altitude", "altitude-adjusted perc", "altitude adjusted perc" ]

seo

{ "keywords_en": "rule out PE, rule out pulmonary embolism, VTE, PE risk, PE criteria, embolism rule out, PE calculator, perc rule, pe rule out, pulmonary embolism rule out, kline r/o, pe r/o, clinical signs pe, clinical signs r/o PE, kline dvt, perc dvt, PERC score, perc calc, perc r/o, perc rule out, pe rule out criteria, pulmonary embolism r/o, pulmonary embolism rule out criteria, PERC-Altitude Rule for Pulmonary Embolism", "meta_description_en": "The Altitude-adjusted PERC Rule for Pulmonary Embolism rules out PE if no criteria are present; includes SaO₂ adjustment for altitude. " }

specialty

[ "Cardiology", "Critical Care", "Emergency Medicine", "Family Practice", "Hematology and Oncology", "Hospitalist Medicine", "Internal Medicine", "Primary Care", "Pulmonology", "Surgery (General)" ]

departments

[ "Cardiac", "Hematologic", "Oncologic", "Respiratory" ]

tags

[]

version_number

1

versions

[]

related

[ { "calcId": 347, "short_title_en": "PERC Rule", "slug": "perc-rule-pulmonary-embolism" }, { "calcId": 115, "short_title_en": "Wells' Score for PE", "slug": "wells-criteria-pulmonary-embolism" }, { "calcId": 10138, "short_title_en": "Age-Adjusted D-dimer", "slug": "age-adjusted-d-dimer-venous-thromboembolism-vte" } ]

ismed

false

section

[ "whenToUseViewed", "pearlsPitfallsViewed", "whyUseViewed", "nextStepsViewed", "evidenceViewed" ]

cleaned_departments

[ "cardiology", "hematology", "oncology", "pulmonology" ]

cleaned_use

[ "In patients who present to the emergency department with chest pain or dyspnea and have a low pre-test probability for PE.", "In patients who present to the emergency department with chest pain or dyspnea and have a low pre-test probability for PE.", "A negative PERC-Altitude means PE can be ruled out and does not require further work-up (D-dimer or CTPA).", "This test is for patients who live at high altitude (>4000 ft). Use the originalPERC Rulefor patients who live at low altitudes." ]

pub

false