[Simple Formula to Predict Residual Amount of Continuously Infused Rocuronium in the Body].

BACKGROUND: When antagonism is performed using sugammadex after continuous infusion of rocuronium, if the total amount of residual rocuronium can be esti- mated prior to performing antagonism, antagonism without excess or deficiency of sugammadex will be made possible. We therefore prepared a simple formula to predict residual amount of rocuronium in the body, which can be easily applied in clinical setting, and veri- fied it using Tivatrainer©. METHODS: 1. Pharmacokinetics of rocuronium was simulated, using a 3-compartment model. The following assumptions were made to derive the simple for- mula : when rocuronium is continuously infused to reach the steady state plasma concentration, an equal concentration in each compartment is reached. Only the amounts of rocuronium infused to the central com- partment and rocuronium excreted from there are thus considered, and these two amounts are in balance. For pharmacokinetic parameters, we referred to V. Saldien, Anesth Analg 2003 ; 97 : 44-9. 2. The prepared simple formula was verified using Tivatrainero. We considered a model in which initial boluses of 0.3, 0.6, 0.9, and 1.2 mg · kg(-1) were adminis- tered, and continuous infusion began at 30 minutes at the rate of 0.2, 0.3, 0.4, 0.5, 0.6, and 0.8 mg - kg-1 - hr-1. Patients with body weight of 50, 60, 70, and 80 kg were investigated. RESULTS: 1. The derived simple formula was as fol- lows : Q=0.74 X R Q Total residual amount of rocuronium (mg) R Dose per hour (mg · hr(-1)) 2. The predicted value of the total residual amount obtained from the simple formula was consistent with the value predicted by Tivatrainer© with a high preci- sion within the error of 1.4%. Convergence time until the stable state was reached varied depending on the condition. However, it took approximately 150 minutes after the beginning of continuous infusion.for the error between values predicted by the simple formula and Tivatrainer© to stabilize within 5 mg. CONCLUSIONS: We prepared a simple formula to esti- mate the total residual amount of rocuronium at a steady state. The value predicted by the simple for- mula agreed with the value predicted by Tivatrainer) with a high precision.

[Difficult airway management during emergency tracheostomy in a patient with severe rheumatoid arthritis].

We experienced difficult airway management in a 65-year-old woman with acute dyspnea due to bilateral recurrent nerve palsy suffering from severe rheumatoid arthritis for fifty years. Her cervical spine was ankylosed and could not be extended at all. Tracheostomy was planned under local anesthesia because of difficulty of endotracheal intubation, possibility of airway obstruction and laryngeal edema. In this condition, the surgical area was narrow and difficult to approach. The surgical bleeding and blood-aspiration into the tracheostomy site occurred followed by airway obstruction. A rigid tracheal tube could not be inserted through the tracheal incision and SpO2 decreased to 81%. We inserted a percutaneous cricothyroidotomy cannula through the tracheal incision and superimposed HFJV on her spontaneous ventilation. Assisting the ventilation in this way finally, a spiral endtracheal tube was inserted and her oxygenation became stable.

[Evaluation of the different doses of olprinone for continuous infusion after cardiopulmonary bypass for coronary artery bypass surgery].

BACKGROUND: We evaluated the hemodynamic efficacy of combined cathecholamine and three different continuous infusion doses of olprinone (0.05, 0.1, 0.3 microgram.kg-1.min-1) in 24 cases (0.05 group: 8 cases, 0.1 group: 8 cases, 0.3 group: 8 cases) undergoing coronary artery bypass grafting (CABG). METHODS: Olprinone was administered as a single dose (0.1 mg.kg-1) into the venous reservoir of the CPB circuit 15 min prior to the end of emergence from CPB, followed by continuous infusion. Hemodynamics were measured at the time of preCPB (M 0), just after the end of CPB (M 1), pre chest closure (M 2) and after chest closure (M 3). Cathecholamines were used to maintain mean arterial pressure (> 65 mmHg) and cardiac index (> 3.0 l.min-1.m-2). Hemodynamics (at M 0, M 1, M 2 and M 3) and the number of cases requiring combined cathecholamine were compared among the 3 doses. RESULTS: Three doses showed no significant difference on hemodynamics. In the number of cases requiring combined cathecholamine, group 0.3 were significantly lower than group 0.05 at dobutamine, and group 0.05 were significantly higher than group 0.1 and 0.3 at norepinephrine. CONCLUSIONS: The higher continuous infusion dose of olprinone (0.3 > 0.1 > 0.05 microgram.kg-1.min-1) can diminish the number of cases requiring combined cathecholamine administration during coronary artery bypass grafting.