Background: Right heart failure (RHF) in the intensive care setting is an under-diagnosed, yet serious condition that carries a significant morbidity and mortality. The patho-physiology of RHF has been extensively studied and found to be most commonly caused by pulmonary embolism, acute cor-pulmonale, severe left ventricular failure, right ventricular infarction and in the setting sepsis. One rarely encountered etiology of RHF is one-lung-ventilation (OLV) leading to insurmountable right heart strain. Case Report: A 62 year old presented with recurrent urinary retention secondary to prostatic hypertrophy. Computed Tomography of chest showed mass in left upper lobe. Endo-bronchial biopsy of mass in left lung resulted in pulmonary hemorrhage. OLV via selective ventilation of only the right lung was employed which resulted in pulmonary hypertension and shock. Conclusion: We believe that in a hypotensive patient undergoing OLV, the practitioner must consider the possibility of obstructive shock secondary to the right heart strain generated by this technique. If RHF is suspected, we recommend obtaining an echocardiogram to detect signs of right heart strain. If strain in present, OLV must be stopped while the patient returns to hemodynamic stability. Further studies regarding the role of one lung ventilation as a cause of obstructive shock will be helpful.