April 22, 2019

Background: Syncope and presyncope are common presenting complaints to the Emergency Department. Orthostatic vital signs are often included in the ED evaluation of syncope to assess for volume depletion despite their poor performance characteristics as previously discussed. In particular, it is important to understand that older adults often have abnormal orthostatic vitals at baseline,  due to numerous causes including medications, despite having a normal physiologic state (Ooi 1997, Aronow 1988). In spite of the evidence, orthostatic vital signs measurements continue to be recommended by the AHA/ACC/HRS guidelines (Shen 2017) and occupy valuable provider and nursing time.

April 3, 2019

Take Home Points on Non-Inferiority Studies

  • Non-inferiority studies should be done when a new treatment (or diagnostic modality) requires less resources (cost or time), is easier for the patient or has a lower side-effect profile.
  • Non-inferiority study design largely negates the protections against bias added by blinding and randomization.
  • Non-inferiority studies can be used to manipulate clinicians when a superiority study would be more appropriate.

March 21, 2019

Background: Rapid Sequence Intubation (RSI)  is a common procedure performed by both emergency clinicians and intensivists. Although the procedure is complex, the major pieces are pre-oxygenation, administration of a sedative agent in close proximity with a paralytic, laryngoscopy and placement of an endotracheal tube without the provision of any ventilations during the process. The avoidance of bag-mask ventilations (BMV), or any positive pressure breaths, rests on the belief that those breaths can distend the stomach and lead to regurgitation and aspiration. For this to happen, the force of the breath must exceed the pressure of the lower esophageal sphincter (~ 20 mm Hg). Critically ill patients presenting with airway compromise cannot be guaranteed to have a fasting state, regurgitation and aspiration is a major concern.

However, there’s another side to this. Many of our patients who are critically ill have intrapulmonary shunting; portions of the lung are atelectatic, filled with fluid, blood, or pus and not being oxygenated though they are being perfused. Blood running through these portions of the lung will be deoxygenated and will lower the overall O2 content of blood entering the systemic circulation after mixing with blood coming from ventilated regions. This shunting at least partially explains why we see patients rapidly desaturating during intubation. Positive pressure can recruit atelectatic portions of the lung that are not involved in gas exchange thus decreasing the physiologic shunt and increasing the patient’s oxygen reserve.

Despite decades of experience with RSI we continue to look for better approaches since the procedure still poses serious risks to the patient. Recent modifications that have seen wide adoption include using the bed-up-head-elevated (BUHE) position, suction assisted laryngoscopy for airway decontamination (SALAD) and bougie first intubation, though there are many more. Now, a publication in the NEJM makes us question the core principle of BMV during RSI.

March 20, 2019

Take Home Points on Oncologic Emergencies:

  1. Hyperviscosity Syndrome happens when elevated WBCs or severe hyperproteinemia cause high serum viscosity and micro-circulatory problems in patients with Waldenstrom’s macroglobulinemia, multiple myeloma or acute leukemia. Be suspicious of this syndrome in these patient’s when they present with the classic triad of mucosal bleeding, visual disturbances, and neurological symptoms or with any end organ failure.
  2. Tumor Lysis Syndrome results from high turnover of malignant cells resulting in severe metabolic derangements including hypocalcemia, hyperkalemia, hyperphosphatemia, hyperuricemia, AKI, metabolic acidosis. Be suspicious of this in patients presenting with edema, hematuria, fatigue, weakness, altered mental status or symptoms that go along with specific metabolic derangement, particularly if they recently received chemotherapy, radiation or high dose steroids.