Viva and Structured Oral Examinations in Intensive Care Medicine

Jeyanathan, Jeyasankar

• Verlag: tfm Publishing Ltd
• Jahr: 2018
• ISBN:
  9781910079607
• Thema: Medicine
• Thema: Emergency Medicine & Critical Care

The objective structured clinical examination (OSCE) has become widely employed in intensive care medicine (ICM) exams such as the UK Final Fellowship of Intensive Care Medicine (FFICM), the European Diploma of Intensive Care (EDIC) exam, or the Australia and New Zealand Fellowship of the College of Intensive Care Medicine (CICM). This book is not only an essential tool for the rehearsal of OSCEs in preparation for these exams, but also for American and Indian exams, and any other exams within the field of intensive care medicine. The OSCE is a style of examination that requires the candidate to present specific information in a short space of time matched to a prescriptive mark scheme. This book allows candidates preparing for an ICM OSCE to format their knowledge for this type of examination whilst practising and rehearsing against time. The 60 OSCE stations provide a broad array of topics from past exams ranging across the training ICM curriculums. The mark schemes are presented in a short, punctuated form allowing the candidate access to important points, ideal at the sharp end of an exam campaign. The 5 sets of OSCE exams are designed to run as a set of 12. Each set will have an array of clinical scenarios requiring swift assessment, diagnosis, recommendations for investigations and management, whilst also exploring aspects of pathophysiology. There are a number of data-interpretation tools that are incorporated into clinical scenarios as well as standalone stations for electrocardiogram and radiology analysis. This book is an important preparatory tool crucial to the armamentarium of any candidate preparing for an ICM exam.

SET 1

Post-cardiac arrest care

1)What is the mortality following cardiac arrest?

The mortality rates vary significantly depending upon the cause of the cardiac arrest, the age of the patient and the setting in which they arrest. The survival to hospital discharge for all-cause out-of-hospital cardiac arrest in England is 8.6%. The classic consensus was that the out-of-hospital cardiac arrest patients who had early bystander CPR, who were in a shockable rhythm and who were defibrillated early had a better outcome than in-hospital slowly deteriorating patients who were usually in a non-shockable rhythm and had no immediate reversible causes but generalised physiological decline.

2)What is the post-cardiac arrest syndrome?

The post-cardiac arrest syndrome is characterised by the following triad:

•Myocardial dysfunction — also called myocardial ‘stunning’, affecting the heart globally. Early echocardiography will therefore show very poor function, but this generally improves. If the stunning is so severe that there is a low cardiac output despite adequate filling and appropriate peripheral vascular resistance, then the stunned heart may respond well to positive inotropy. Early echocardiography should therefore be avoided unless there is suspicion of valve rupture or a left ventricular aneurysm as a result of the initial insult.

•Reperfusion syndrome — reperfusion of ischaemic tissue releases cytokines and hypoxic metabolites into the circulation. This causes vasoplegia and impaired oxygen utilisation in all tissues. It can also cause hypotension which may be responsive to vasopressor therapy and adequate intravascular filling.

•Hypoxic brain injury — hypoxaemia results in the primary insult of brain cell apoptosis, plus the secondary insult of impaired cerebral autoregulation and subsequent cerebral oedema. This should be managed with the same neuroprotective measures as for head injury, with careful attention to oxygenation and appropriate ventilation, cerebral perfusion pressure maintenance, strict sodium, glucose and seizure control.

3)What are the management priorities post-cardiac arrest?

General management

•The airway should be protected appropriate to the patient’s Glasgow Coma Scale (GCS) score, which may include intubation and mechanical ventilation. Care should be taken to ensure adequate oxygenation and ventilation to a normal PaCO₂ for cerebral protection. Similarly, hyperoxia may be harmful in the post-arrest period.

•Sedation — whilst there are no data to support this, it is standard practice to sedate patients to allow physiological settling and to ‘rest’ the brain. Patients who have had a degree of hypoxic ischaemic cerebral insult may become very agitated in the immediate post-arrest period.

•Cerebral perfusion pressure needs to be maintained — the hypoxic ischaemic time may have affected cerebral autoregulation, with cerebral perfusion dependent upon mean arterial pressure which should therefore be maintained through a combination of fluid resuscitation, inotropes and vasopressors, as required.

Specific management

•The cause of cardiac arrest should be identified and if possible reversed — specifically, patients who have suffered a primary cardiac event should have their coronary arteries catheterised and revascularised.

•Hyperthermia should be avoided (see below).

•Maintenance of normoglycaemia using insulin and dextrose infusions as appropriate — there is a good correlation between poor glucose control post-cardiac arrest and poor neurological outcome.

•Control of seizures if present — seizures increase the cerebral metabolic rate significantly and therefore may further damage an already injured brain. There is a lack of evidence, but seizure prophylaxis post-cardiac arrest should be considered in patients who have had a significant hypoxic-ischaemic cerebral insult.

4)Should we be cooling patients post-cardiac arrest?

There has been conflicting evidence in the recent past regarding cooling post-cardiac arrest:

•Evidence for: two studies from Europe and Australia showed that patients cooled post-arrest had no survival benefit but had a more favourable neurological outcome. Criticism of these trials included the large exclusion rate and the high incidence of hyperthermia in the control group — essentially, they compared hypothermia to hyperthermia.

•Evidence against: a 2013 trial compared cooling to 33°C with targeted temperature management of 36°C and showed no difference in mortality or neurological outcome.

Therefore, the current consensus opinion is that the avoidance of hyperthermia is on a par with therapeutic hypothermia in terms of neurological outcome, and avoids the potential complications associated with cooling patients.

5)How can we prognosticate patients post-cardiac arrest on intensive care?

Predicting outcome following return of spontaneous circulation (ROSC) after a cardiac arrest is difficult to achieve.

Factors associated with a...