HSRT Drawing Logical Inferences 2

Question 1

A patient reports taking ibuprofen 800 mg three times daily for the past 3 weeks for knee pain. He now presents with epigastric pain and dark tarry stools. What is the MOST warranted inference?

Accepted Answer

The patient likely has NSAID-induced gastrointestinal bleeding

Answer

High-dose NSAID use with new GI symptoms (epigastric pain, melena) strongly warrants an inference of NSAID-induced GI bleeding or ulceration.

Question 2

A nurse notes that a post-operative patient's urine output has dropped from 80 mL/hour to 15 mL/hour over 3 hours, blood pressure is 88/54 mmHg, and heart rate is 118 bpm. Which inference is MOST justified?

Accepted Answer

The patient is in hypovolemic shock, likely from post-operative bleeding

Answer

Dropping urine output, low blood pressure, and elevated heart rate together in a post-operative patient most strongly suggest hypovolemic shock from bleeding.

Question 3

A public health analyst observes that counties with more fast-food restaurants per capita have higher rates of type 2 diabetes. The MOST logically cautious inference from this correlation is:

Accepted Answer

There is an association between fast-food density and diabetes rates, but causation requires further study

Answer

Correlation identifies association, not causation. Multiple confounders (socioeconomic status, physical activity levels) could explain the relationship.

Question 4

A clinical lab reports that a test for Disease X has a sensitivity of 95% and a specificity of 60%. A patient tests positive. Which inference about the test result is MOST accurate?

Accepted Answer

A positive result has limited diagnostic value due to the low specificity, meaning many positives are false positives

Answer

Positive predictive value (PPV) is determined by specificity and disease prevalence. Low specificity means a high false-positive rate, limiting the value of a positive result.

Question 5

A respiratory therapist is told: 'Every patient whose O2 saturation dropped below 90% last month received high-flow oxygen therapy.' He now sees a patient receiving high-flow oxygen therapy. He infers that this patient's O2 saturation must have dropped below 90%. Is this inference valid?

Accepted Answer

No — high-flow oxygen may be ordered for other reasons not stated; this is the fallacy of affirming the consequent

Answer

Inferring the cause from the effect (affirming the consequent) is invalid because multiple causes may lead to the same outcome.

HSRT - Health Sciences Reasoning Test Practice Test

HSRT - Health Sciences Reasoning Test Practice Test

HSRT Drawing Logical Inferences 2