A 52 year old obese female with a history of recurrent biliary colic comes to the Emergency Room at Santa Rosa Medical Center with right upper quadrant pain which developed 30 minutes after she ate a fat laden meal. Her vital signs are temp 98, P 98, RR 18 and BP 150/88. Her abdomen shows mild right upper quadrant pain but no frank peritoneal signs. Her chemistry panel demonstrates elevated total bilirubin, alkaline phosphatase and gamma gluamyl-transferase. What is the most appropriate next step in the diagnostic evaluation?

20 times a minute is usually the average respritory rate of an adult. additionally the patient is breathing on his own, is clearly maintaining his airway, and is intaking a sufficient amount of air. you shouldn't use a bag valve mask, cpap, or other form of positive pressure ventilation, unless the patient has lost control of his airway, and is not breathing (apneic) or has rapid breathing or slow and shallow respirations. this patient would most likely and should be put on an non-rebreather mask or nrb attached to 100% high flow oxygen at 15 l/min. don't use a nasal cannula, as the amount of oxygen it provides is limited with a rate of 6 l/min.