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

The patient has an unrelated gastrointestinal ulcer

Answer

The dark stools are caused by dietary iron supplementation

Answer

The epigastric pain indicates a primary hepatic disorder

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

The patient has acute kidney injury from nephrotoxic medications

Answer

The patient is dehydrated from inadequate oral intake

Answer

The patient has urinary retention from catheter blockage

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

Fast-food restaurants cause type 2 diabetes in those communities

Answer

Communities with high diabetes rates attract more fast-food businesses

Answer

The correlation is coincidental and has no health policy implications

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

The patient almost certainly has Disease X because the sensitivity is 95%

Answer

The test result is highly reliable because sensitivity exceeds specificity

Answer

The positive result means the patient definitely has Disease X

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

Yes — the rule is universal, so any patient on high-flow oxygen had a low saturation

Answer

Yes — this is a valid application of modus ponens

Answer

No — the rule only covers last month, which may not apply to current patients

Question 6

A nurse practitioner reviews a research abstract stating: 'In our cohort, patients with sleep duration under 6 hours had 2.3× higher odds of developing hypertension over 10 years.' The MOST logically defensible inference is:

Accepted Answer

Short sleep duration is associated with increased odds of hypertension, and this warrants screening and counseling in clinical practice

Answer

Short sleep causes hypertension, so prescribing longer sleep will lower blood pressure

Answer

The finding is not clinically relevant because odds ratios are weaker than relative risks

Answer

Patients with hypertension should have their sleep assessed to treat the underlying cause