## 2 Discussion  
### The Processes of Clinical Decision Making: The Four Models, with Clinical Examples  
#### 2.1.1 Overview  
The skeletal framework of clinical decision making is predicated on the steps involved in hypotheco-deductive reasoning adapted from the scientific method: hypothesis generation, evaluation, refinement, and verification [3]. The more recent literature describes slight variations of the above, although the root of medical decision making is based on a stepwise process of validations in the initial and subsequent face-to-face encounters with patients [4]. More \"ornate\" frameworks exist based on the complexity of the individual cases, with advanced clinical decision making in clinical medicine now able to insert its \"tentacles\" within and between any number of steps of this elaborate paradigm (Figure 1). In fact, such a scaffold may be applied to various degrees to a universal approach in the applications of scientific inquiry and pursuits of many different disciplines. The preeminent processes in clinical decision making currently encompass four models:  
* Rational Model,
* Evidence-Based Model,
* Intuitive Model,
* Participatory/Shared Decision-Making Model. The Rational Model emanates from the study of cognitive science, which consists of critical thinking, metacognition (thinking about thinking), introspection, reflection, and communication [5,6]. This approach pre-supposes adequate data and information for well-defined and structured clinical scenarios coupled with the availability of the required time. This process can optimally be used in cases such as those of slow-growing (or even aggressive) malignancies or long-term conditions, including chronic kidney, pulmonary, and heart disease, in which a number of possible diagnostic studies, imaging techniques, and laboratory and genetic analyses are available for the evaluation and treatment of the specific malady. The Evidence-Based Model parallels the Rational Model as it is predicated on high-quality research engendering empirical pathways, practice guidelines, and clinical decision rules, although it also includes the wishes of the patient [7,8]. Conversely, in my opinion, the many nuances, variables, and anecdotal elements so often present in clinical medicine and contributing to its \"art form\" are not wholly emphasized in this model. By way of illustration, this process of decision making is not optimal in all cases, such as with certain complex illnesses in which the infusion of packed red blood cells would likely benefit the patient. The above would occur only through the implementation of transfusion thresholds higher than those recommended by societal guidelines (as the guidance is currently based on a trigger of a low level of hemoglobin to administer transfusions). Another example would include the treatment of hypertension, in which adherence to current guidelinesfrom a number of medical societies is not always applicable and appropriate for all patients. These would include those with cerebrovascular and renovascular diseases, which often require higher blood pressures for the adequate perfusion of blood to these tissue beds. As a result, although beneficial in many circumstances, this approach is not always tailored to the individual manifesting unique pathophysiological characteristics. The Intuitive Model employs spontaneous decisions based on the physician's combination of experience, wisdom, instincts, and, at times, emotions [9]. This unique approach is frequently utilized in acute and critical circumstances, such as those seen in the Emergency Departments with cardiac arrests or intraoperatively when unanticipated anatomical challenges or complications (such as hemorrhage) spontaneously occur. Under these conditions, the decision-making process must take place very rapidly, and, at times, immediately due  
Figure 1: Diagnostic Paradigm of Clinical Decision Making. to the emergent nature of the condition. Instinctual responses based on the experience of the physician are thus required at times.