Anesthetic management in during cardiac surgery in the patient with methemoglobinemia
Edvin Bihorac, Nedim Çekmen
Baskent universitesi
Giriş: We aimed of presenting a case of female patient scheduled for coronary artery bypass (CAB) and mitral valve replacement (MVR) surgery due to coronary artery disease (CAD) and mitral valve stenosis and insufficiency(MS + MR). During the previous intervention, mitral baloon valvuloplasty, profound hypotension and cardiac pre-arrest state had occurred possibly due to intraoperative methemoglobinemia (MetHb)
Olgu: Our patient is 67 year old woman with the history of hypertension (HT),CAD, MS + MR and MetHb diagnosed during previous cardiac intervention (mitral valvuloplasty) 20 years ago. After standard monitorization and intubation, right jugular central catheter and right radial artery have been canulated. During induction and maintanence we refrained of using local anesthestics (LA) and nitrate containing compounds. Although methylene blue was ready for use, operation went uneventhful. Patient was transferred as intubated to the Intensive care unit where she was extubated next day and discharged 10 days later.
Tartışma ve Sonuç: MetHb is a rare, potentially reversible cause of hypoxia in the perioperative setting. MetHb occurs when the ferrous iron (Fe2+) of oxyhemoglobin is oxidized to the ferric iron (Fe3+) of methemoglobin which has less oxygen carrying capacity leading to hypoxia(1) . Factors increasing risk for developing MetHb include cardiovascular or pulmonary diseases and/or anemia(2). The most common drugs that cause MetHb include LA,nitrate containing drugs, antibiotics such as dapsone,etc.In our case we refrained from using lidocain during induction and glyceril trinitrate in order to avoid casuing MetHb. Symptoms may vary from confusion,tachypnea to coma,seizures, lactic acidosis, arrhythmias etc. Methylene blue, ascorbic acid, hyperbaric oxygen therapy, and blood transfusion for severe cases are the treatment options (3). In the patients known to have methemoglobinemia we should avoid drugs that may provoke this condition and if it still occurs we should use methylene blue as the first choice of treatment.
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