Secrets of Experts in Clinical Decision Making: Schemes of

Care

Dr. Imad Salah Ahmed Hassan MD FACP FRCPI MSc MBBS

Consultant Physician & Pulmonologist

Chairman, Knowledge Translation Committee

Department of Medicine

King Abdulaziz Medical City

Riyadh, Saudi Arabia

imadsahassan@yahoo.co.uk

Step 1 Gather Information (History & Physical)

Step 2 Summarize the Case using Technical Language

Step 2

• Comprehensive but Concise, Text-book-Like:• Must contain patient’s name, gender, age, • ± occupation, ± nationality ± racial/geographic

origin, relevant Past History/Social History/Family History, Drug/Allergic History, Symptoms + duration –in technical terms, Relevant physical signs in technical conclusive terms.

Step 2: Case Presentation Example

• 67 yr old male• Bird/pigeon breeder, smoker• 3 days history of fever, cough with yellow sputum, left

stabbing chest pain that is worse with breathing and coughing and breathlessness

• Clinically, breathless, cyanosed, disoriented to time, person and place, Temperature 39.1C, BP 86/50, RR 32/min, bilateral coarse crepitations, bronchial breathing left lower zone.

• Chest x-ray: left basal consolidation

Step 2: Case Technical Summary

• 67 year old, smoker and bird-breeder presenting with a 3 days history of productive cough, dyspnea and left pleuritic chest pains.

• Clinically confused, cyanosed, febrile, tachypnoiec and hypotensive with signs of left lower zone consolidation.

Step 3 Propose a Diagnosis

Step 3: Use Bed-side Diagnosis Schemes: PR, 3Rs, HD

• Pattern-recognition PR• “ Rules of Thumb” Smart Heuristics• Rule-Out worst Scenario ROWS• Red Flags (symptoms or signs of more serious

pathology-usually after diagnosis is made) etc• Hypothetico-deductive HD Strategies (from H&P)

Step 3: Use Bed-side Diagnosis Schemes

• High-Fidelity/Reliability Pattern Recognition (spot diagnosis): Shingles, Acromegalic Facies

• Low-Fidelity/Reliability Pattern Recognition (error-prone): Central chest pain radiating to the left arm plus sweating, nausea and vomiting =Acute Coronary Syndrome (other possibilities still exist!)

• Smart Heuristic “Rules of Thumb”: early morning headache and vomiting=Increased intracranial pressure

• ROWS: Meningitis, SAH, CVA, Temporal Arteritis etc in a patient with headache

• Red Flags: rest pain, weight loss, neurological deficits etc in a patient with low back pain

Step 3: Use Bed-side Diagnosis Schemes

• Hypothetico-deductive Strategies (from H&P) • Detailed history• Clues from all components of the history• Comprehensive physical examination• May need to revert to investigations if no diagnosis is clear.

Step 4 Differential Diagnosis

Step 4: Use Differential Diagnosis Schemes

• Differential Diagnosis Cognitive Aids: Anatomical Physiological Pathological

An important cause of missing a diagnosis is not thinking of it!!! i.e. not putting a differential diagnosis.

Step 4: Use Differential Diagnosis Schemes

Anatomical Differential Diagnosis

Physiological Differential Diagnosis

Etio-pathological Differential Diagnosis

Pain Syndromes: e.g. central chest pain may be categorized as arising from the heart, aorta, esophagus, chest wall etc

Shock: this may be hypovolemic, distributive, obstructive or cardiogenic

Congenital or Hereditary

Swellings: e.g. a neck swelling differential diagnosis will include the thyroid, lymph nodes, vascular, skin etc

Thrombosis: This may be related to a vessel wall pathology, blood constituents or flow rate.

Acquired: 1. Traumatic 2. Infective: viral, bacterial

etc 3. Inflammatory/auto-

immune 4. Vascular/degenerative 5. Neoplastic/para-

neoplastic 6. Metabolic/endocrine 7. Drug-induced/ poisoning 8. Deficiency diseases 9. Psychogenic 10. Idiopathic/cryptogenic

Step 5 Order Tests (Rationally)

Step 5: Pre-test Probability Assessment for Rational Test Ordering

• Frugal (i.e. simple and applicable) Heuristics Probability Assessment: The AP Scheme

• Order tests: based on Test Sensitivity, Specificity and Likelihood Ratios

• Baye’s may not be a practical and quick pre-test probability assessment approach!

Step 5: Pre-test Probability Assessment for Rational Test Ordering: AP Scheme

• Frugal Pre-test Probability Assessment: The AP Scheme

1. Absent Alternative: No alternative plausible bed-side Diagnosis: Yes/No

2. Presence of Strong Risk factor for the condition: Yes/No

• Interpretation: High Probability (2 YES) or Intermediate Probability(1 YES 1 NO) or Low Probability (2 (both) NO)

Step 5: Pre-test Probability Assessment for Rational Test Ordering

• SpIn: highly specific tests are useful for ruling-in the diagnosis when positive ( use for high and intermediate probabilities) e.g. spiral CT for suspected pulmonary embolism.

• SnOut: highly sensitive tests are useful for ruling-out the diagnosis when negative ( use for low probabilities) e.g. d-dimer for suspected pulmonary embolism.

Sensitivity•How often is

the test result correct for persons in whom the disease is known to be present?

•Sensitivity - the proportion of people

with disease who have a positive test.

SENSITIVITY

•in a group of 100 patients with bacterial pneumonia, 80 had a raised C-reactive protein CRP: the sensitivity of CRP for diagnosing bacterial pneumonia is thus 80%.

Example:

Specificity•How often is

the test result correct for persons in whom the disease is known to be absent?

•Specificity - the proportion of people without the disease who have a negative test.

SPECIFICITY

•in a group of 100 patients without pneumonia, 10 had a raised C-reactive protein CRP: the specificity of CRP for correctly excluding pneumonia is thus 90%.

Example:

Likelihood Ratio•the likelihood that a given

test result would be expected in a patient with the target disorder compared to the likelihood that the same result would be expected in a patient without that disorder.

•In general, a positive likelihood ratio of 4 or more is useful in ruling-in the target disorder. A negative likelihood ratio of less than 0.3 is useful in ruling-out the target disorder.

Likelihood ratio:

Likelihood Ratio•Example: A raised

Jugular venous pressure JVP in a patient with a history suggestive of congestive heart failure CHF has a positive LR of 5.8 and a negative ratio of 0.66. Thus the presence of a raised JVP rules-in the diagnosis of CHF. Its absence is not as useful in ruling it out.

Likelihood ratio:

Step 6Confirm &

Comprehensively give a Diagnostic Label

The BESDiagnosis Scheme

Better diagnostic labeling thereby assisting in implementing individualized, evidence-based interventions.

• 1. The Bed-side Clinical Diagnosis

• 2. The Etiological or Precipitating Cause

• 3. The Severity Score or Grade.

Bedside Clinical Diagnosis

Etiological/

Precipitant

Severity

Guideline-friendly Bed-side Diagnosis, Etiology, Severity (BESD)

“the diagnosis that would explain all the symptoms & signs”

“what is the Cause”

“how bad”• CURB-65: CAP• Killip Classes: ACS• Glasgow CS• Croup Score• APGAR Score• Blatchford score: UGI

bleed• Ranson Score:

Pancreatitis• Emerg. Severity Index

Usefulness of The Scheme• Failure to consider the precipitant or cause in

addition to the clinical diagnosis will inevitably result in deficient care input and a poorer outcome.

• Appropriate evidence-based interventions to optimize outcome according to SEVERITY will be different specifically with regards the sites of care and recommended Immediate Interventions.

Usefulness of The Scheme• e.g.• Usual Label: “Admitted with an asthma

exacerbation…………• Guideline-Friendly Evidenced-Based Label:

1. The Bed-side Clinical Diagnosis: Asthma Exacerbation

2. The Etiological or Precipitating Cause: Poor Inhaler Technique

3. The Severity Score or Grade: Life-threatening Asthma

Usefulness of The Scheme

• e.g. Continued….• Implications:• Site of Care: ICU• Therapy for life-threatening attacks: Oxygen, systemic

steroids, combination nebs etc• Prevention of re-admission: training on inhaler technique

Step 7 Therapeutic Interventions

Step 7: Therapeutic Interventions: The 5S Scheme

• Contextual• Patient-centered

– Therapeutic Cognitive Aid: Site of Care, Symptomatic, Supportive, Specific and Specialty Referral (5S).

Immediate Therapeutic Interventions:The 5S

Site of Care

Symptomatic

Supportive

Specific

Specialty Referral

e.g. CCU

e.g. cardiology

e.g. Analgesics

e.g. thrombolytic

e.g. IV fluids

The 5 S Scheme

• Site of Care: Guidelines, unambiguously dictate sites of care for specific disease severity scores.

• ICU for CURB-65 of 3 or more• CCU for Acute Coronary Syndrome

The 5 S Scheme

• Symptomatic treatment: is important as it directly alleviates patient discomfort.

Analgesia for painAnti-emetics for nausea and vomitingAnti-pyretics for fever

The 5 S Scheme

• Supportive care: to improve physiological derangements before damage becomes irreversible and until the precipitant is brought under control by its specific intervention may be life-saving.

IV Fluids for dehydrationBicarbonate for acidosisOxygen for hypoxia

The 5 S Model

• Specific Care: directed at the primary cause.

Antibiotics for infectionThrombolytics for acute myocardial

infarctionAppendicectomy for acute appendicitis

The 5 S Scheme

The 5 S Model

• Specialty Referral: guidelines recommend early specialty or sub-specialty referral for specific acute illnesses.

GIT team for a patient with hematemesisCardiology for a patient with ACSPhysiotherapy for a patient with stroke

The 5 S Scheme

The complete input: An Example1. Bedside-Clinical Diagnosis Acute BA Exacerbation

2. Precipitant Poor Inhaler Technique

3. Severity Life-threatening

4. Site of Care ICU

5. Symptomatic Bronchodilators

6. Supportive Oxygen, IV Fluids

7. Specific Bronchodilators, Steroids

8. Specialty Referral ICU, Pulmonary, Asthma Educator

Step 8 Prepare for Discharge

Step 8: Prepare for Discharge (ACT)

• Assess Response to Treatment (Subjective & Objective)

• Criteria for Discharge• Timing of Follow-up

The ACT Scheme

• Assess Response to Treatment: Subjective & Objective

• Criteria for Discharge: Clinical, Laboratory, Radiologic, Social etc

• Timing of Follow-up : Clinic Appointment for disease and drug monitoring

Good Luck