Use of dexmedetomidine for awake crainiotomy / 대한마취과학회지

No abstract available.

Caudal analgesia reduces the sevoflurane requirement for LMA removal in anesthetized children / 대한마취과학회지

BACKGROUND: An anesthetic state can reduce adverse airway reaction during laryngeal mask airway (LMA) removal in children. However, the anesthetic state has risks of upper airway obstruction or delayed emergence; so possibly less anesthetic depth is advisable. Caudal analgesia reduces the requirement of anesthetic agents for sedation or anesthesia; it is expected to reduce the sevoflurane requirement for LMA removal. Therefore, we determined the EC(50) of sevoflurane for LMA removal with caudal analgesia and compared that to the EC(50) without caudal analgesia. METHODS: Forty-three unpremedicated children aged 1 to 6 yr were enrolled. They were allocated to receive or not to receive caudal block according to their parents' consent. General anesthesia were induced and maintained with sevoflurane and oxygen in air. EC(50) of sevoflurane for a smooth LMA removal with and without caudal analgesia were estimated by the Dixon up-and-down method. The LMA was removed when predetermined end-tidal sevoflurane concentration was achieved, and the sevoflurane concentration of a subsequent patient was determined by the success or failure of the previous patient with 0.2% as the step size; success was defined by the absence of an adverse airway reaction during and after LMA removal. EC(50) of sevoflurane with caudal block, and that without caudal block, were compared by a rank-sum test. RESULTS: The EC(50) of sevoflurane to achieve successful LMA removal in children with caudal block was 1.47%; 1.81% without caudal block. The EC(50) were significantly different between the two groups (P < 0.001). CONCLUSIONS: Caudal analgesia significantly reduced the sevoflurane concentration for a smooth LMA removal in anesthetized children.

The Neuromuscular Pharmacodynamics for Rocuronium at the Adductor Pollicis and the Flexor Hallucis Brevis Muscle / 대한마취과학회지

BACKGROUND: Neuromuscular block is commonly monitored using the adductor pollicis (AP) because of its easy access. However, the hand may not always be accessible for neuromuscular monitoring during surgery. In that situation, monitoring of the flexor hallucis brevis (FHB) secondary to stimulation of the tibial nerve at the ankle joint may be used as an alternative. METHODS: During propofol and remifentanil anesthesia, acceleromyography of the thumb and big toe were recorded. Single twitch responses were measured simultaneously after cumulative administration of rocuronium from 80 to 200microgram/kg at intervals of 40microgram/kg. Furthermore, the amount of rocuronium required for 50% and 95% twitch height depression were calculated. Rocuronium was infused continuously to maintain 5% to 15% twitch responses. We also obtained the onset, duration of action, and antagonism effect of neostigmine from both muscles via neostigmine (20microgram/kg) administration. RESULTS: ED50 and ED95 were significantly lower in the AP than in the FHB. The highest twitch response at peak and neostigmine antagonism were significantly higher in the FHB than in the AP. However, there was no significant difference in the onset time or duration of neostigmine between AP and FHB. CONCLUSIONS: Due to its resistance to rocuronium, the onset of FHB is not a good indicator of optimal conditions for tracheal intubation. Also, because of its higher antagonism effect, there is potential risk of overlooking a residual block. Sufficient recovery of the block should be readjusted to estimate recovery in the FHB with the use of other reliable clinical tests.

Methylene Blue for Vasoplegic Syndrome after Cardiopulmonary Bypass: A case report / 대한마취과학회지

Vasoplegic syndrome (VS) occurs in 8-10% of patients following cardiac surgery and is associated with increased morbidity and mortality. Nitric oxide and guanylate cyclase play an important role in this response. Methylene blue, an inhibitor of guanylate cyclase, has recently been advocated as an adjunct in the treatment of catecholamine-refractory VS. We experienced a case of VS after aortic arch replacement surgery, presenting severe hypotension refractory to high-dose norepinephrine and vasopressin. Administration of methylene blue 100 mg led to immediate recovery of arterial pressure. We report this case and review the role of methylene blue in the treatment of catecholamine-refractory VS.