RecruitingClinical trialNovel Method to Assess Hepatic Regeneration and Predict Hepatic Related Morbidity After Partial Hepatectomythe investigators will pursue two specific aims: (1) to monitor the extent of heme oxygenase induction (by measuring endogenous CO production) in relationship to the extent of hepatic resection (2) to assess the production of CO in patients following liver resection and correlate these findings to the rate of liver regeneration and liver function.