CORRESPONDENCE: LETTERS TO THE EDITOR
Does inhaled nitric oxide support the hemodynamic of spontaneous breathing patients with cardiogenic shock related to right ventricular myocardial infarction? Reply
Ignacio Inglessis, MD and
Marc J. Semigran, MD*
* Cardiology Division, Massachusetts General Hospital, Bigelow 842, 32 Fruit Street, Boston, MA 02114 (Email: msemigran{at}partners.org).
We thank Dr. Bendjelid for his interest in our work (1). We agree that the majority of our patients were studied while undergoing positive pressure ventilation. As only three patients in our study population did not require mechanical ventilation, our ability to extrapolate our results to patients with right ventricular myocardial infarction (RVMI) not receiving mechanical ventilation is limited. Nonetheless, there was no difference in the improvement in cardiac index observed between those patients breathing nitric oxide (NO) who were mechanically ventilated and those who were not.
Dr. Bendjelid also raises the concern that positive pressure ventilation may act to prevent the development of acute left ventricular (LV) failure that may occur during NO inhalation, and that LV failure may arise in nonventilated patients. Left ventricular filling pressures have been found to increase during NO inhalation in patients with severe LV systolic dysfunction (2,3). The RVMI patients in our study had primarily RV dysfunction, and the degree of LV dysfunction was not as severe as in those patients in whom the pulmonary capillary wedge pressure (PCWP) has been reported to increase during NO inhalation. Furthermore, we excluded patients with a PCWP >25 mm Hg from study. In the three nonventilated RVMI patients in our study, we did not observe an increase in their PCWP while they were breathing NO for 10 min.
In future studies of the effects of sustained NO inhalation in RVMI patients, it will be important to observe the hemodynamic effects of this agent in patients who receive positive pressure ventilation as well as those who do not. Patients with severe LV systolic function should be monitored carefully during chronic NO inhalation because of the possibility of their developing pulmonary venous hypertension.
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References
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- Inglessis I, Shin JT, Lepore JJ, et al. Hemodynamic effects of inhaled nitric oxide in right ventricular myocardial infarction and cardiogenic shock J Am Coll Cardiol 2004;44:793-798.[Abstract/Free Full Text]
- Semigran MJ, Cockrill BA, Kacmarek R, et al. Hemodynamic effects of inhaled nitric oxide in heart failure J Am Coll Cardiol 1994;4:982-988.
- Loh E, Stamler JS, Hare JM, et al. Cardiovascular effects of inhaled nitric oxide in patients with left ventricular dysfunction Circulation 1994;90:2780-2785.[Abstract/Free Full Text]
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Does inhaled nitric oxide support the hemodynamic of spontaneous breathing patients with cardiogenic shock related to right ventricular myocardial infarction?
- Karim Bendjelid
J. Am. Coll. Cardiol. 2005 45: 965.
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