MCQ 3

Q3.A young male is brought to the emergency dept after having been submerged for a prolonged period of time at a nearby pond.CPR was performed at the scene.The patient is being ventilated by a mask and bag upon arrival in the emergency dept.A brief examination reveals that the patient has no obvious sites of trauma and is conscious but not communicative.His BP is 90/60,pulse 120, temp 36 degree C and RR 30.Cardiac rhythm reveals sinus tachycardia.Pulse oximetry reveals O2 saturation of 83 percent.Which of the following is best method to reverse the patient's apparent hypoxemia?

  A. Administration of sodium bicarbonate.

  B. Administration of acetazolamide

  C. Administration of supplemental oxygen

  D. Application of continuous positive airway pressure and administration of supplemental oxygen

  E. Administration of supplemental oxygen and endotracheal suction to remove aspirated fluid

Answer and explanation

Answer : "D"

explanation: 

90% of the drowning patients aspirate fluid; however ,the vast majority  aspirate less than 22mL/kg.Though aspiration of fresh water can produce acute hypervolemia with dilutional natremia and possibly even hemolysis, these are rare occurrences. Aspiration of sea water can cause hypovolemia with ensuing hypernatremia. In the absence of documentation of such an electrolyte problem, no specific therapy is required.

Aspiration of water of any type leads to considerable venous admixture (i.e., ventilation-perfusion abnormalities), which can produce hypoxemia .

The most important therapeutic maneuvers, after resuscitation on the scene,  are to provide supplemental O2, IV access , and transportation to a hospital where the patient can be evaluated for adequacy of ventilation, cardiac function, and blood volume. The best way to reverse drowning related hypoxemia is the application of continuous positive airway pressure(CPAP). CPAP may be combined with mechanical inflation of the lung as needed; the latter technique may be particularly effective in those who have aspirated fresh water, which leads to changes in surface tension characteristics of pulmonary surfactant. Correction of severe metabolic acidosis with bicarbonate is controversial. Finally, the universal need of corticosteroid therapy and antibiotics is no longer accepted.