Photo of Warren (Warren) Myron Zapol, MD

Warren (Warren) Myron Zapol, MD


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Anesthesia, Critical Care & Pain Medicine

Clinical Interests
  • Critical care
  • Acute respiratory distress syndrome (ARDS)
Medical Education
  • MD, University of Rochester School of Medicine and Dentistry
  • Residency, Massachusetts General Hospital|Residency, NIH, National Heart, Lung, and Blood Institute
Board Certifications
  • Anesthesiology
  • Boston: Massachusetts General Hospital
Insurances Accepted
  • United Healthcare (non-HMO) - ACD
  • United Healthcare (non-HMO) - PBO
Patient Age Group

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Dr. Zapol is currently the Director of the MGH Anesthesia Center for Critical Care Research at Massachusetts General Hospital, where he collaborates with many researchers to explore the pulmonary circulation of mammals in normal and disease states. Over the last 20 years, his laboratory has focused upon the physiological and pathophysiological roles of nitric oxide (NO). Based on his lab's pioneering studies, inhaled NO (INO) is now used to treat approximately 30,000 patients per year in the USA to vasodilate the pulmonary circulation and augment arterial oxygenation. For many hypoxic infants and for children after heart surgery, this inhaled therapy is life-saving. In December 1999, the FDA approved INO therapy to treat term newborn infants with hypoxic respiratory failure; this therapy was developed in our lab.

The Zapol lab is presently closely allied with Dr. Kenneth Bloch's laboratory. Together they are focusing on the storage lesion of aged blood cells, and methods for preventing the toxic effects of extracellular hemoglobin that is released by hemolysis in malaria or genetic diseases such as sickle cell anemia. In addition, the Zapol lab is studying how to make the transfusion of heme-based oxygen carriers both safe and effective for transfusion in the field.

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Research & Publications

Research Summary

Research Areas

Inhaled nitric oxide, stored blood transfusion, cerebral malaria, hemoglobin gas binding

Description of Research

My research is directed at understanding a wide range of critical illnesses that can be therapeutically treated with novel inhaled gases. Inhaled nitric oxide (NO) is a central focus of this laboratory's research, both as a selective pulmonary vasodilator and a safe method for loading the body with NO donor molecules. As a selective pulmonary vasodilator, inhaled NO is used to treat pulmonary hypertension and to improve ventilation-perfusion matching. NO inhalation leads to the formation of circulating NO metabolite which can neutralize oxygen free radicals, activate soluble guanylate cyclase (to make cGMP) and prevent the side effects of excessive scavenging of endogenous NO molecules by transfusion of stored red cells. We also study hemoglobin, discovering small molecules that alter its affinity for gases such as oxygen, carbon monoxide and NO. The prevention and treatment of acute lung injury is also studied in this laboratory with mouse models of ventilator-induced lung injury and transfusion.  My group studies inhaled nitric oxide in children with cerebral malaria and adults with stored blood transfusion. Methods for the economical  in situ manufacture of Nitric Oxide by electrical sparks in air are being explored. Animal models used in the laboratory extend from mice to sheep, with a special focus on translational research to improve the care of critically ill patients
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News & Events


Anesthesia, Critical Care and Pain Medicine
55 Fruit Street
Boston MA, 02114-2696
Phone: 617-726-3030
Fax: 617-726-3032

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