Friday, November 16, 2007

Images in Clinical Medicine - Quiz

A patient is transferred to the ICU for stabilization prior to surgery. The patient is complaining of back pain. The blood pressure is 180/110 and the heart rate is 95 per minute. The surgeon says that he wants the patient optimized and that the patient needs emergency surgery.

  • Based on the CT scan slices that are shown, what does the patient have?
  • Do you agree with the surgeon's decision, based on the limited CT views?
  • What would you do to "optimize" this patient?
  • What further information about this patient do you want?

This image and the clinical scenario were contributed by Daniel Zurcher (Washington University final year medical student).

More on this post to follow...

Saturday, November 10, 2007

Are intensivists prognostic pessimists?

An article appeared in the British Medical Journal suggesting that ICU clinicians have unwarranted prognostic pessimism that results in some patients, who might otherwise survive, being denied admission to ICU. In this study, clinicians were asked to estimate the likelihood of survival of patients with COPD and asthma exacerbations who required admission to ICU. The study found out that clinicians underestimated six-month survival by 13%. Sixty two percent of patients survived compared with the clinicians’ prediction of 49%.

  • To me this seems like pretty good prediction. But I’m, after all, just a lousy ICU clinician.
  • I have worked in both the UK and the US medical systems. My impression is that, if there is a tendency to unwarranted prognostic pessimism in the UK, there may be a tendency to unwarranted prognostic optimism in the US.

Clinician pessimism, according to the article, was particularly marked for the patients with the poorest clinician prognosis. Clinicians predicted a 180-day survival of around 3%, whereas the actual survival was 36%.

  • The most important question may not be whether the patients survived, but rather how they survived. If they survived with a good quality of life, then the poor prognostic prediction – prognostic pessimism - could have had dire consequences. If they survived with a miserable quality of life, choosing not to pursue ICU admission may have been appropriate.

  • Why may ICU clinicians be prognostic pessimists? Is this true for all clinicians? My experience is that surgeons are prognostic optimists. When I have expressed pessimism about a patient’s prognosis, my surgical colleagues have often pointed out that my seeing patients at their sickest biases my perspective. When patients recover, they often recover dramatically. When we discharge patients from the ICU, they are usually still debilitated. So, perhaps, as intensivists, our perspective is skewed.

A major concern about prognostic pessimism is that we are not uniform in our assessments. Many clinicians focus on different information, and this may lead them to form different conclusions. All ICU clinicians do not reach the same conclusions about a patient’s prognosis even when they are privy to the same information. This has been used to support the implementation of “objective outcome prediction models”. Such models, however, are also error prone as they work for populations BUT not for individuals.

One of the most poignant opinion pieces I have read appeared recently in the journal, JAMA. An experienced ICU clinician was confronted with a dreaded situation; his father had metastatic cancer and was critically ill. His condition was complicated by renal failure. The father and the physician’s family looked to him for guidance. The clinician confessed that being emotionally vested complicated his decision-making and may have affected the clarity of his thinking. After much deliberation, his father and his family, with his sanction, decided not to initiate dialysis. The father died. The ICU physician may at times second-guess this tough decision in moments of emotional turmoil. But, this decision was undoubtedly motivated by love and compassion, and required tremendous strength of character from all parties. In such difficult circumstances, it is vitally important that efforts are made to ensure that all family members are like-minded and agree with the chosen course of action.

Decisions regarding the pursuit of aggressive therapy versus palliative care must be addressed with patients and their families by physicians who are competent and experienced in end-of-life care as this will have a profound impact on both the quality of care delivered and effective use of limited hospital resources. A major problem is that regional culture plays an important part in end of life decision-making. Such cultural differences not only affect patients and their families but also the health care workers who make and carry out such decisions. This can lead to tension if there are cultural differences between physicians and patients’ families or among health care workers themselves.

Perspectives from a biased ICU Clinician:

  1. Sometimes withholding or withdrawing advanced life support is the most compassionate course.
  2. Quality of life, not just survival, should be considered in making decisions.
  3. It may be helpful to seek the opinion of a colleague who is not emotionally vested in the care of a patient.
  4. We should ask ourselves whether our judgment might be clouded by prognostic pessimism.
  5. Prognostic optimism may be a euphemism for fear of litigation or defensive medicine.
  6. For an optimistic perspective, always consult a surgeon.
  7. The right to a dignified death should be viewed as a fundamental human right, just as the right to a dignified life is.
  8. Unwarranted prognostic pessimism may lead to patients being denied life-saving interventions.
  9. Unwarranted prognostic optimism may lead to patients being denied a dignified death.
  10. Even the most insightful clinician may misjudge a patient’s prognosis. It may be better to err on the side of optimism than that of pessimism.

A Little Squeeze Goes a Long Way

A recent paper published in the Lancet renewed our interest in preconditioning, specifically remote preconditioning (RIPC). 57 patients undergoing CABG were randomly assigned to receive three 5-min cycles of right upper arm ischemia, which was induced by an automated BP cuff with the idea that ischemia in one vascular bed will afford protection in another – in this case the heart. Troponin T levels were taken before surgery and at 6, 12, 24, 48, and 72 hours after surgery.

What did they find?

  1. A reduction in troponin T levels starting at 6 hour.
  2. 43% reduction in the area under the curve between control and treatment group.

Are the findings important?

  • This study used a surrogate maker to try to predict clinical outcomes. Although, there is a reduction in the level of Troponin T in the treatment group does this translate to meaningful clinical outcomes (eg. Atrial fibrillation, length of stay, etc). The authors do not report these findings. Certainly, we are concerned about myocardial injury, but a difference between a Troponin of 0.4 vs 0.7 is that clinically significant?

Are there any concerns?

  • The authors reported no ill outcome in the treatment group. However, there maybe ethical concerns with the study design. Numerous papers have demonstrated the cardioprotective effects of volatile anesthetic. In this study a total intravenous anesthetic technique was used to perhaps amplify the results.

What should the intensivist do?

  1. The skeptics will argue that we should do nothing until firm evidence emerges. In fact if firm evidence emerges, it is probably wrong!
  2. The zealots may argue that every ICU patient should have tourniquets applied to every limb, each of which (the tourniquets, not the limbs!) should be intermittently inflated. This may become a new market niche for MAST suits.
  3. The intellectual enthusiasts may argue that we MUST do a raft of randomized controlled studies with RIPC on the ICU.
  4. The pragmatists may argue that this is a benign intervention that should be used, unless there are specific contra-indications (eg. Vascular disease, fistula, etc.).