Questions With reference to clinical studies: a)  Define the term “external validity”. b)  Define the term “bias”. c)  Briefly explain selection bias and measures to reduce it. Answers

A 40 year old man with a history of ankylosing spondylitis and known difficulty with intubation on previous elective surgery is admitted to your ICU for hypoxic respiratory failure.

A 45-year-old man is admitted to the Emergency Department after ingesting an unknown quantity of “headache tablets”. His initial complaints are nausea, vomiting, shortness of breath and tinnitus. Fluid resuscitation has been commenced. You are asked to assess him as he is getting more dyspnoeic.

Outline the potential mechanisms of ventilator associated lung injury in patients with Acute Respiratory Distress Syndrome and the steps that can be taken to minimise them.

You are asked to review a 64-year-old male who has been brought to the Emergency Department having been burned in a house fire. He is drowsy and confused with a persistent cough and unable to give a coherent history.

The following questions refer to implantable cardiac pacemakers and implantable cardiac defibrillators.

3.1 A 70-year-old, 42kg female with chronic renal failure, Type 2 diabetes and a history of alcohol abuse was admitted for management of leg ulcers infected with MSSA. Ten days into her admission she became increasingly short of breath and was referred to ICU.