Ephedrine reduces the pain from propofol injection.

UNLABELLED: One hundred seventy-six patients (ASA physical status I or II) presenting for elective surgery were randomly allocated into six study groups to compare the incidence of propofol-induced pain after pretreatment with different doses of ephedrine as compared with lidocaine. Patients in Group P (n = 30) received saline placebo; patients in Group L (n = 30) received 2% lidocaine 40 mg; patients received ephedrine 30 microg/kg (Group E30, n = 28), 70 microg/kg (Group E70, n = 30), 110 microg/kg (Group E110, n = 30), and 150 microg/kg (Group E150, n = 28), respectively, followed 30 s later by propofol 2.5 mg/kg. A blinded anesthesiologist asked the patient to evaluate the pain score (verbal rating scale and face pain scale). The incidence and intensity of pain was less in the lidocaine and ephedrine groups than in the placebo group (P < 0.01). Before tracheal intubation, the arterial blood pressure was decreased in the P and L groups, and after intubation, hemodynamics were increased in the E110 and E150 groups, respectively (P < 0.05). We concluded that pretreatment with a small dose of ephedrine (30 and 70 microg/kg) reduced the incidence and intensity of propofol-induced pain with a lesser decrease in arterial blood pressure than from propofol alone in lidocaine pretreatment. IMPLICATIONS: Propofol is a widely used IV anesthetic for the induction of anesthesia, but it often causes local pain when administered into peripheral veins. A small dose of ephedrine reduces the incidence and intensity of the pain without significant adverse hemodynamic effects during induction.

Tactile assessment for the reversibility of rocuronium-induced neuromuscular blockade during propofol or sevoflurane anesthesia.

We sought to determine whether tactile train-of-four (TOF) count can predict the efficacy of neostigmine administration for rocuronium-induced blockade during propofol or sevoflurane anesthesia, and to follow subsequent recovery until the TOF ratio reached 0.9. One-hundred-sixty patients, divided into eight equal groups, were randomly allocated to maintenance of anesthesia with propofol or sevoflurane. The tactile response of the adductor pollicis to TOF stimulation was evaluated on one arm, and the mechanomyographic response was recorded on the other. Neuromuscular block was induced with rocuronium 0.6 mg/kg and maintained with rocuronium to 15% of the control first twitch in TOF. Neostigmine 0.07 mg/kg was administered on reappearance of the first (Group I), second (Group II), third (Group III), or fourth (Group IV) tactile TOF response in each anesthesia. At this time, sevoflurane or the propofol dosage was reduced in each group (n = 20 in each group). The times from administration of neostigmine until the TOF ratio recovered to 0.7, 0.8, and 0.9 were recorded. The times [median (range)] to TOF ratio = 0.9 were 8.6 (4.7-18.9), 7.5 (3.4-9.8), 5.4 (1.6-8.6), and 4.7 (1.3-7.2) min in Groups I-IV during propofol anesthesia, respectively, and 28.6 (8.8-75.8), 22.6 (8.3-57.4), 15.6 (7.3-43.9), and 9.7 (5.1-26.4) min in corresponding groups during sevoflurane anesthesia, respectively (P < 0.0001). We recommend more than 2 TOF responses with propofol anesthesia and 4 TOF responses with sevoflurane anesthesia for adequate reversal within 10 and 15 min, respectively. The more tactile TOF responses present at the time of reversal achieved greater adequate recovery; however, tactile TOF responses are not a completely reliable predictor within a reasonable time period.

Residual paralysis induced by either vecuronium or rocuronium after reversal with pyridostigmine.

UNLABELLED: We investigated postoperative residual curarization after administration of either vecuronium or rocuronium with reversal by pyridostigmine in 602 consecutive patients without perioperative neuromuscular monitoring. On arrival in the recovery room, neuromuscular function was assessed both by acceleromyography in a train-of-four (TOF) pattern and also clinically by the ability to sustain a head-lift for >5 s and the tongue-depressor test. Postoperative residual curarization was defined as a TOF ratio <0.7. One fifth of 602 patients (vecuronium, 24.7%; rocuronium, 14.7%) had a TOF <0.7 in the recovery room. There were no significant differences in the TOF ratios between 10 mg and 20 mg of pyridostigmine. The patients with residual block had several associated factors: the absence of perioperative neuromuscular monitoring, the use of pyridostigmine, which is less potent than neostigmine, a larger dose of vecuronium, shorter time from the last neuromuscular blocker to TOF monitoring, or peripheral cooling. We conclude that significant residual neuromuscular block after vecuronium or rocuronium was not eliminated even with reversal by a large dose of pyridostigmine. IMPLICATIONS: Without monitoring, the significant residual neuromuscular block after vecuronium or rocuronium is not eliminated even by reversal with a large dose of pyridostigmine and can still be a problem in the recovery room.

The dose effect of ephedrine on the onset time of vecuronium.

UNLABELLED: A small dose of ephedrine decreases the onset time of rocuronium and cisatracurium; however, ephedrine might be associated with adverse hemodynamic effects. The appropriate dose of ephedrine has not been determined. We, therefore, studied 120 patients anesthetized with fentanyl 2 microg/kg and propofol 2-2.5 mg/kg who were randomly divided to receive either ephedrine (30, 70, or 110 microg/kg) or saline. During propofol anesthesia, the neuromuscular block was monitored by mechanomyography by using submaximal current of train-of-four stimulation every 10 s. To determine cardiac output, a transcutaneous Doppler probe was placed externally at the suprasternal notch. Tracheal intubation was performed by a blinded investigator at 2 min after vecuronium. Neuromuscular block, intubating conditions, and hemodynamic effects were measured during the induction of anesthesia. Both ephedrine 70 and 110 microg/kg improved intubating conditions at 2 min after vecuronium; however, 110 microg/kg was associated with adverse hemodynamic effects. We conclude that ephedrine 70 microg/kg given before the induction of anesthesia improved intubating conditions at 2 min after vecuronium, probably by increased cardiac output without significant adverse hemodynamic effects. IMPLICATIONS: Ephedrine 70 microg/kg given before the induction of anesthesia improved tracheal intubating conditions at 2 min after vecuronium by increased cardiac output without significant adverse hemodynamic effects.