Case 1
A 95-year-old woman (135 cm and 40 kg) presented with right intertrochanteric femoral fracture requiring surgery. She had a history of hypertension, dyslipidemia, and dementia, which were controlled by amlodipine and olmesartan, pravastatin, and donepezil, respectively. Physical examination findings were normal, and laboratory examination revealed mild anemia with hemoglobin (Hb) level of 11.8 g/dL and coagulopathy of prothrombin time [PT] of 58% (PT-international normalized ratio, 1.3) probably owing to advanced age. Transthoracic echocardiography, electrocardiography, and respiratory function test revealed no abnormalities.
Anesthetic chart is shown in Fig. 1. In the operating room, the patient’s vital signs were as follows: blood pressure (BP), 136/70 mmHg; heart rate, 88 bpm; and oxygen saturation on room air, 92%. BIS value was > 90 before inducing anesthesia. General anesthesia was induced by intravenous administration of fentanyl (50 μg), remifentanil (0.15 μg/kg/min), and remimazolam (1.2 mg/kg/h). She lost consciousness 4 min after initiation, and subsequently tracheal intubation was performed after administration of rocuronium (40 mg). After the operation was started, the remimazolam dose was adjusted so that the BIS value became 40–60 concomitantly with 0.125 μg/kg/min of remifentanil infusion. Eventually, remimazolam dose was decreased to 0.2 mg/kg/h although BIS value remained < 40. The operation was uneventfully completed with a small amount of blood loss in approximately 90 min. During the operation, she remained hemodynamically stable with administration of ephedrine 4 mg bolus and phenylephrine 50 μg bolus only twice to maintain systolic BP at > 90 mmHg, without the need of continuous administration of vasopressor agents. At the time of suture, 50 μg of fentanyl was administered, the remifentanil dose was decreased to 0.075 μg/kg/min, and remimazolam was maintained at 0.2 mg/kg/h. After completion of the operation, administration of these agents was discontinued and 200 mg of sugammadex was administered. Although 2.0 mg of remimazolam was administered as a bolus owing to the BIS value of > 70 during postural change for radiographic examination, 10 min after the bolus administration, she recovered consciousness without flumazenil and received extubation. Any consciousness problem, including resedation or postoperative cognitive function disorder, was not observed during the postoperative course. After rehabilitation, she was discharged on postoperative day 15.
Case 2
A 103-year-old woman (approximately 150 cm and 40 kg) presented with right intertrochanteric femoral fracture requiring surgery. She had a history of chronic kidney disease (CKD) due to hypertension, which was treated with amlodipine, furosemide, and valsartan. Moreover, she took ticlopidine for the prevention of cerebral infarction. Physical examination results were normal, and laboratory examination revealed stage 3b CKD with serum creatinine level of 1.18 mg/dL (estimated glomerular filtration rate, 31.6 mL/min/1.73 m2) and mild anemia with Hb level of 10.0 g/dL. Transthoracic echocardiography and electrocardiography revealed no abnormalities.
Anesthetic chart is shown in Fig. 2. In the operating room, she was hemodynamically stable with vital signs as follows: BP, 157/58 mmHg, heart rate, 84 bpm; and oxygen saturation on room air, 94%. BIS value was > 90 before anesthesia. General anesthesia was induced by intravenous administration of fentanyl (100 μg), remifentanil (0.3 μg/kg/min), and remimazolam (1 mg/kg/h). She lost consciousness 3 min after initiation, and subsequently tracheal intubation was performed after administration of rocuronium (40 mg). After the operation was started, the remimazolam dose was adjusted so that the BIS value became 40–60 concomitantly with 0.1–0.3 μg/kg/min of remifentanil infusion. Eventually, the remimazolam dose was decreased to 0.1 mg/kg/h with BIS value of approximately 50–60. The operation was uneventfully completed with a small amount of blood loss in approximately 100 min. During the operation, she remained hemodynamically stable without administration of any vasopressor agents, except when general anesthesia was induced. After completion of the operation, administration of remifentanil and remimazolam was discontinued and 200 mg of sugammadex was administered; 8 min after discontinuation of these agents, she recovered consciousness without flumazenil and received extubation. Any consciousness problem, including resedation or postoperative cognitive function disorder, was not observed during the postoperative course. After rehabilitation, she was discharged on postoperative day 29.