Spontaneous Circulation

Spontaneous Circulation focuses on advanced ECG interpretation, cardiac pharmacology, hemodynamic assessment and resuscitation, and managing acute coronary syndrome. It is devoted to translating the best evidence-based treatments from critical care, resuscitation, and trauma for bedside use in the emergency department.

Monday, May 12, 2014

Upstream Problems

He had been through this before. The patient, a 57-year-old man, had come through the doors of this emergency department many times. He had a favorite seat in triage. He knew what questions the nurse would ask him once he was in a room, and that the doctor would repeat those same questions. Then tests and labs, then moved upstairs for a couple of days before going home, hopefully feeling better. He knew all of this. Today, though, everything he thought he knew was wrong.

He had once considered himself lucky. He even survived a gunshot to the chest as a young man. But that notion had faded long ago. His health had been getting worse for years. He suffered with diastolic heart failure, COPD, and stage 3 chronic kidney disease brought on by years of poorly treated hypertension and diabetes. He had been told during one of his stays in the hospital that he had depression. He didn't doubt it. He had resigned himself to never getting completely well, but the past couple of days had been even worse.

He had not slept in days, and was extremely fatigued. He was unable to catch his breath, and was in mild distress. Oxygen saturations were 70%, which improved with supplemental oxygen by Oxymizer. He was not having any chest pain, and his blood pressure was in the 100s mm Hg systolic, way below his baseline and surprising given that he had not taken his medications for weeks. Exam was remarkable for generalized edema, diffuse crackles, and JVD elevation. Creatinine was nearly twice his baseline, and BNP was extremely elevated. Serial troponin measurements were normal. An ECG and x-ray were obtained and are shown in Figures 1 and 2.

Figure 1. Electrocardiogram on presentation.


Figure 2. AP Chest radiograph on presentation.

The ECG shows a normal sinus rhythm with short PR interval. A Q-wave is present in lead III, and nonspecific T-wave changes show in the precordial leads. It is unchanged in comparison with previous tracings. The chest x-ray shows pronounced cardiomegaly, vascular congestion, and diffuse interstitial opacities consistent with pulmonary edema.

The diagnosis seemed clear. It was the same diagnosis the patient knew, the same diagnosis he had had every other time he had come to the hospital: exacerbation of his diastolic heart failure, with cardiorenal syndrome. He was treated with nitroglycerin and bumetanide/metolazone to promote diuresis. Which worked. Sort of. Despite a large volume of urine output, his shortness of breath was not improving, and his creatinine continued to worsen. A transthoracic echocardiogram was obtained to assess cardiac function and volume status. Watch this video to see the patient’s echocardiogram showing the parasternal long axis view, and this one to see the patient’s echocardiogram showing the parasternal short axis view.)

Given the patient’s body habitus, the transthoracic echocardiogram was a technically difficult study. Echocardiographic contrast agents in this situation can be useful to help with interpretation. Contrast, usually some form of gas bubble that scatters ultrasound waves, is used for two principle reasons: to detect left to right shunts and to opacify the left ventricle to define the endocardial border, which allows better determination of ventricular dimensions, wall motion, and ejection fraction. Contrast is given intravenously, and it needs to transverse the pulmonary circuit to opacify the left ventricle. Larger bubbles are more stable, but the bubbles need to be less than 10 micrometers to pass through the pulmonary capillaries. The bubbles can be stabilized by surrounding them with a durable structure and using inert gases rather than air. Table 1 lists commonly used echo contrast agents.

The echocardiogram with the help of contrast showed normal left ventricular size and performance (ejection fraction of 65%) without any wall motion abnormality. The right atrium and ventricle were markedly enlarged, however, and there was decreased right ventricular systolic contractility. The right-sided dilation was causing significant tricuspid insufficiency. The estimated pulmonary artery systolic pressure was 27 mm Hg above the right atrial pressure. A notable finding was a D-shaped septum, implying a relative increase in right ventricular end-diastolic pressure. These findings were concerning for increased pulmonary arteriolar vascular resistance versus worsening volume overload. The patient underwent a right heart catheterization to assess this.


Pressure tracing from right heart catheterization. 

The right heart catheterization showed that the pulmonary artery pressure was 72/31 (mean 46) mm Hg with an occlusion pressure is 18 mm Hg. This indicates essentially high-normal left-sided pressures and severe pulmonary hypertension. Much to everybody’s surprise, the patient, rather than suffering from left ventricular diastolic failure (heart failure with preserved ejection fraction) that would require elevated left ventricular end diastolic pressures, was actually underfilling his left ventricle. The patient had severe pulmonary hypertension with right-sided heart failure (cor pulmonale).

Multiple possible etiologies for the patient’s pulmonary hypertension included COPD, chronic cocaine use causing pulmonary fibrosis/ILD, and chronic hypoxia from untreated obstructive sleep apnea. He had a prescription for CPAP, but had refused to wear it. The right ventricle was hypertrophied and dilated, which gives an indication that this was chronic rather than acute. (Table 2.)

Unfortunately for the patient, his right heart failure continued to decompensate. Despite aggressive attempts at reducing the pulmonary hypertension with inhaled prostacyclins and nitrous oxide, he required escalating vasopressor support. He developed refractory shock and multiorgan failure, and his family elected to pursue comfort care measures.