Sources of variability in uncertain medical decisions in the ICU: a process tracing study

Consistency of medical decision making (equity) is an important component of quality of care. When patients with chronic obstructive pulmonary disease (COPD) present with an exacerbation needing respiratory support they may die if it is not provided. However, if the disease has reached its terminal stage, ventilation will prolong the process of dying. The ventilation outcome is uncertain and there is evidence of variability when this decision is made, the sources of which are not well understood.

To identify sources of variability and propose ways of tackling them in order to promote equity in this type of medical decision.

Six case histories were selected from hospital records of COPD patients. Fourteen senior doctors from seven hospitals in the West Midlands participated. A process tracing approach was used which consisted of (1) withholding case information until specifically requested by the doctors, (2) estimating survival during the decision making process, and (3) concurrent questioning regarding information interpretation and its impact on survival estimates and decisions.

The observed decision variability was attributed to doctors attaching importance to different information, gathering different information, and interpreting information differently. There were significant differences between doctors in the amount of information requested.

Differences in information gathering and interpretation by clinicians can result in different decisions being made about the same patient. This variation may exist for other uncertain medical decisions and may be tackled by providing clinicians with prognostic models in the form of usable decision aids.