The patient was a 62-year-old man with a height of 167 cm and a body weight of 60 kg.
He has long shown cyanosis on his lips, and his mother had the same symptom.
The patient visited another hospital complaining of diarrhea, nausea, and dizziness, where a blood test revealed elevated liver enzymes (aspartate aminotransferase 122 IU/l, alanine aminotransferase 203 IU/l, lactate dehydrogenase 813 IU/l), total bilirubin (2.4 mg/dl), and C-reactive protein level (16.1 mg/dl), and an echocardiographic examination revealed cardiac tamponade; thus, he was referred to our hospital. Because an ascending aortic dissection (DeBakey II) was found by computed tomographic examination, the patient was advised to undergo emergency surgery on the same day of diagnosis.
He demonstrated cyanosis on his face and limbs, so even with oxygen inhalation, the percutaneous oxygen saturation (SpO2) was 75%. As the patient had cardiac tamponade, we suspected a decline in SpO2 due to heart failure. The arterial blood was venous blood-like blue-black blood. Transthoracic echocardiography revealed pericardial effusion, tricuspid regurgitation, and aortic regurgitation; however, neither ventricular collapse nor wall motion disorder was recognized, and the ejection fraction was 76%. Blood pressure was also maintained at 110–120/70–80 mmHg, and the heart rate was maintained at 70–80/min by using antihypertensive drugs, suggesting that the patient had a hemoglobin abnormality rather than a reduction in SpO2 due to heart failure. Therefore, the patient was suspected of having a hereditary disease. Subsequently, his case was referred to the hematology department; however, a definitive diagnosis could not be established. As the surgery had to be performed urgently, we investigated the cause of cyanosis after the surgery. Preoperative blood gas analysis and blood counts revealed the following results: PaO2 219 mmHg, SaO2 75%, Hb level 13.3 g/dl, hematocrit (Ht) 40.9%, white blood cell 11.30 × 103/μl, red blood cell 4.24 × 106/μl, and platelet 302 × 103/μl.
Anesthetic management
Anesthesia was induced with midazolam 5 mg, fentanyl 0.4 mg, and vecuronium 10 mg and maintained by the inhalation of 0.3%–0.5% isoflurane and 0.5–1.0 mg/kg/h propofol, as well as the adequate administration of vecuronium and fentanyl. After the induction of anesthesia, a pulmonary artery catheter was placed through the right internal jugular vein, and blood sampling from the pulmonary artery and radial artery was performed.
The SpO2 monitor showed a reading of 75%, and the blood gas analysis revealed the following results: PaO2 435 mmHg, SaO2 80.9%, Hb level 13.6 g/dl, and Ht 41.6% under the condition of FiO2 100%. The cardiac index was 2.3 L/min/m2, the mixed venous oxygen saturation (SvO2) was 61%, and the regional oxygen saturation (rSO2) of the forehead was 56%. When the surgery started, the pericardiotomy was opened, and after the release of cardiac tamponade, the cardiac index increased to 3.5 L/min/m2 and SvO2 increased to 68%. However, other values did not change. The intraoperative SvO2 maintained the latter half of the surgery was above 60%, and the intraoperative rSO2 of the forehead was maintained above 50%. Furthermore, the cardiac index was maintained above 3.0 L/min/m2. Additionally, there was no increase in lactate.
An ascending aortic replacement surgery was performed. Cardiopulmonary bypass (CPB) was initiated by right axillary artery blood flow after the superior and inferior vena cava were removed, and ascending aortic replacement surgery was performed under hypothermic circulation arrest with a bladder temperature of 22 °C. The anesthesia time was 375 min and the operation time was 340 min. After the patient was transferred to the postoperative intensive care unit, the divergence between PaO2 and SpO2 was confirmed; however, the circulation dynamics were stable and PaO2 was normal. The patient underwent tracheal extubation at 15 h postoperatively. He was moved to the general ward on the 3rd hospitalization day and was discharged without complications on the 32nd hospitalization day. During hospitalization, the patient was referred to the hematology department for a detailed examination and was diagnosed as having Hb Kansas through genetic analysis at 2 months after surgery.