When people with pulmonary arterial hypertension and progressive right heart failure suffer an acute insult or decompensation severe enough to land them in the ICU, it’s usually not pretty. Hemodynamic management is complex and difficult,with low cardiac output resulting both from right ventricular weakness and high right sided filling pressures reducing stroke volume from the left ventricle (ventricular interdependence). In this concise clinical review, Marius Hoeper and John Granton acknowledge “[t]here is a paucity of data to guide clinicians caring for acute right heart failure in PAH.” Then they give us their take on it, supported by the best information they could amass (“Our recommendations are based on physiological principles, published reports as well as personal experience.”)
Their main points:
- TRANSFER these patients to a center with pulmonary hypertension specialists at the first opportunity, if you are not at one already.
- People with group 1 and 4 (pulmonary arterial hypertension, and chronic thromboembolic pulmonary hypertension) are most likely to suffer the syndrome of acute right heart failure with low cardiac output and high RV filling pressures. People with group 2 or 3 (left heart failure or lung disease) may get volume overloaded but rarely have low cardiac output due to RV failure.
- Because of the increased recognition and earlier treatment of PAH in general, these days, by the time these (mostly treated) patients reach the ICU, they’re really, really sick.
- Fluid management is exceptionally complex and difficult, because hypervolemia and hypovolemia can be harmful. Although adequate preload must be maintained, overfilling the right ventricle (by giving crystalloid for hypotension) can dilate it further, compressing the left ventricle and reducing cardiac output (ventricular interdependence 2). (Although I’ve always wondered how this jibes with the conventional wisdom that the treatment for acute right ventricular failure due to myocardial infarction is “volume, volume, volume!”) In most cases, patients are volume overloaded and diuresis will improve cardiac output.
- It goes without saying, find and treat any precipitating cause (infection, arrhythmia, failure of vasodilator drug delivery, or pulmonary embolism being among the most common treatable ones).
- Regarding arrhythmias, maintenance of sinus rhythm (not just rate control in SVT) seems to be vitally important; chemical and/or electrical cardioversion may be necessary, followed by radiofrequency ablation if refractory. Atrial flutter is easier to control than atrial fibrillation. Avoid calcium channel blockers and beta blockers if possible (they reduce cardiac function).
- They advocate for Swan-Ganz placement as standard, with serial measurements of hemodynamic paramaters, central venous oxygen saturation, and lactate. BNP levels may provide trends but aren’t useful in real-time decision-making during periods of instability.
- They prefer dobutamine when inotropes are necessary. Norepinephrine may also be necessary, especially if vasodilators are also being used.
- They advocate for maintenance of a hemoglobin of 10 g/dL, without evidence (although iron deficiency is known to be harmful in PAH).
- Intubation and CPR are ill-advised, as they rarely help return someone with disease this advanced to a functional state.
- Heart-lung transplant, with extracorporeal membrane oxygenation as a bridging technique, is a last-ditch but potentially lifesaving option, even in critically ill patients.
Clinical Takeaway: Don’t try this without a pulmonary hypertension expert around, unless you absolutely must. In which case, may the Force be with you.
Hoeper MM, Granton J. Intensive Care Unit Management of Patients with Severe Pulmonary Hypertension and Right Heart Failure. Concise Clinical Review. Am J Respir Crit Care Med 2011;184:1114-1124.