Cardiac Tamponade
A 17-ycar-old woman with no past medical history is admitted to the ED after a stabbing x 2 to the upper posterior left side. She is lethargic and in no rcspiratory distress. Her pulse oximetry reading is 95%, HR 120 beats/min (sinus tachycardia), BP 105/85 mm Hg, and respiratory rate 24 brcaths/min nonlabored. The team immediately provides supplemental oxygen with a 100% non-rcbrcathcr (NRB) and two large bore IV catheters with normal saline (NS) infusions. An emergent FAST examination does not reveal a cardiac tamponade or tension pncumothorax. After the infusion of 1.5 L of NS, the patient's pulse oximetry (Sao2) reading is 97%, HR 98 bcats/min (sinus rhythm), BP 118/80 mm Hg, and rcspiratory rate (RR) 20 brcaths/min non-laborcd.
The patient is transferred to the surgical intensive care unit (SICU) for 24-hour observation.
In the SICU, the patient continues to be lethargic but has a Glasgow coma scale (GCS} score of15 and is arousablc. She has no pain or distress but her skin is coot Her tympanic temperature is 98.0"F. Her BP decreases to 75165 mm Hg, with an HR of110 bcats/min. The NS infusion is increased to wide-open and the physician is called immediately. While the physician is on the way to the SICU, the nurses' reassessment finds clear breath sounds bilaterally and distant heart tones with jugular venous distention. The RR is 24 brcaths/min with Soa2
of95% on 2 L nasal cannula. The nurse continues the IV boluses until the physician arrives. Upon arrival the physician orders a FAST examination and a change in the oxygen to a 100%NRB.
The team suspects a tamponadc but the repeat FAST examination results do not support their suspicion. The patient is unstable so a CT scan cannot be safely completed. Thus, the patient is prepared for emergency exploratory thoracotomy. In the OR, the patient was found to have a large posterior pericardia! bloody effusion causing tamponadc, which was decompressed. The patient then returns to the SICU postoperatively.
Which of the following reasons best explain why NS was used 'versus a vuopre1aor when the patients BP decreued?
(A) Dextrose solutions arc hypotonic and do not expand the vascular bed as well as NS.
(B) The goal is to expand the intravascular volume to offset the pressure caused by the blood in the pericardia! sac.
(C} Normal saline is an isotonic fluid.
(D) Vasoprcssors do not expand the intravascular space.
(E) All of the above.
Why did two preYiou1 FAST examinations fail to show a cardiac tamporuule?
(A) The FAST is not 100% predictive in all cases of tamponade.
(B} In cases of penetrating trauma to the chest an exploratory thoracotomy is the standard of care if symptoms of a tamponade persist despite negative FAST findings and if a CT scan cannot be done.
(C) The FAST is user dependent.
(D} All of the above.