Nitric Oxide to Treat Pulmonary Embolism

Inclusion Criteria: * Age \>/= 18 * Pulmonary imaging-proven PE, as interpreted by local radiologist * At least one predictor of RV dysfunction: 1. echocardiography with RV dilation or hypokinesis, 2. estimated RVSP \>40mm HG, 3. RV\>LV on CTPA, 4. elevated troponin I (\>0.1 ng/mL) or natriuretic peptide (BNP \> 90 pg/mL), 5. screening bedside cardiac ultrasound with color flow capability that shows RV dysfunction, 6. RV strain on ECG * Plan to admit to a bed with telemetry capability Exclusion Criteria: * Vasopressor support at time of enrollment * Pregnancy * Plan by clinical care team to use lytic or surgical embolectomy * Plan by clinical team to use platelet inhibiting drugs * Contraindication to anticoagulation * Altered mental status such that the patient is unable to provide informed consent * Inability to use a nasal cannula or face mask * Comfort care measures instituted * Supplemental oxygen requirements greater than can be administered via nasal cannula in order to maintain Sa)2 \> 80% * Pneumothorax with decompression * Serum MetHb \> 10% * Recent use of drugs known to increase cGMP * Use of nitroprusside or nitroglycerin within the last 4 hours * Use of any other nitrates with in the past 24 hours * Use of a fibrinolytic medicine within the past 14 days