Biomedical subjects

L W Stinson

Publications and source records attributed to L W Stinson.

3 recordsLinked to original sources

PubMed1996

Evaluation of cisatracurium, a new neuromuscular blocking agent, for tracheal intubation.

PURPOSE: The primary objective of this study was a blinded, randomized comparison of the recommended intubating dose of atracurium (0.5 mg. kg-1) with an approximately equipotent dose of cisatracurium (0.1 mg. kg-1) during N2O/O2/propofol/fentanyl anaesthesia. METHODS: Eighty ASA physical status 1 or 2 patients, 18-70 yr of age, within 30% of ideal body weight, scheduled for elective low to moderate risk surgical procedures were studied. Adductor pollicis evoked twitch responses were measured with a Grass FT 10 force displacement transducer (Grass Instruments, Quincy, MA) and continuously recorded on a Gould multichannel polygraph (Gould Instrument Systems, Cleveland, OH) after induction of anaesthesia. RESULTS: Increasing the initial dose of cisatracurium (from 0.1 to 0.15 and 0.2 mg. k-1, decreased mean time of onset (from 4.6 to 3.4 and 2.8 min, respectively), and increased mean time of clinically effective duration (45 to 55 and 61 min, respectively). Recovery to a T4:T1 ratio of 0.7 occurred approximately seven minutes following administration of the reversal agent neostigmine for all treatment groups. Intubation conditions were good or excellent in over 90% of patients in all treatment groups (two minutes after approximately 2 x ED95 doses of cisatracurium or atracurium and 1.5 minutes after 3 x and 4 x ED95 doses of cisatracurium). CONCLUSION: The intubation results reported in this study together with the combination of predictable recovery from neuromuscular block and apparent haemodynamic stability make cisatracurium a potentially useful muscle relaxant in clinical practice.

Adolescent↗

PubMed1995

Train-of-four recovery after pharmacologic antagonism of pancuronium-, pipecuronium-, and doxacurium-induced neuromuscular block in anaesthetized humans.

Previous studies have suggested that the increased duration of action of long-acting neuromuscular relaxants may make their pharmacologic antagonism more difficult and, thus, increase the likelihood of residual block. This hypothesis was tested in healthy, adult humans who received a background of isoflurane/N2O/fentanyl anaesthesia. Study subjects were paralyzed with either pancuronium (N = 8), pipecuronium (N = 8), or the longer-acting relaxant, doxacurium (N = 8). Neuromuscular function was monitored, and, using a blinded, randomized study design, the relaxants were titrated to identify the ED95 dose in each patient. Thereafter, spontaneous recovery was observed until there was 25% of baseline response to the first supramaximal twitch (T1) in a train-of-four (TOF). At this time, the block was antagonized with neostigmine 0.07 mg/kg and glycopyrrolate 0.014 mg/kg i.v., and recovery of TOF was recorded. Spontaneous recovery to 25% of the baseline T1 response occurred at 52 +/- 14 min (mean +/- SD) following administration of either pancuronium and pipecuronium, and 85 +/- 33 min following doxacurium (P < 0.05 for doxacurium versus pancuronium and pipecuronium). In doxacurium-treated patients, reversal of block with neostigmine was less predictable and less complete than with the other two relaxants. For example, the ratio of the fourth to first twitch (T4/T1) of the TOF at 10 and 15 min after reversal was significantly less with doxacurium (59 +/- 14% and 61 +/- 16%, respectively) than with either pancuronium (75 +/- 6% and 75 +/- 10%) or pipecuronium (76 +/- 9% for both).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗

PubMed1994

A computer-controlled, closed-loop infusion system for infusing muscle relaxants: its use during motor-evoked potential monitoring.

A microcomputer-controlled closed-loop infusion system (MCCLIS) has been developed that provides stable intraoperative levels of partial neuromuscular blockade. Complete neuromuscular blockade interferes with intraoperative motor-evoked potential (MEP) monitoring used for patients undergoing surgical procedures that place them at risk for spinal cord ischemia. Nine patients were studied during which the MCCLIS maintained stable levels of partial neuromuscular blockade and allowed transcranial magnetic motor-evoked potential (TcM-MEP) monitoring during thoracoabdominal aortic aneurysmectomy. The use of TcM-MEP for monitoring intraoperative spinal cord function was balanced against surgical considerations for muscle relaxation with 80% to 90% neuromuscular blockade fulfilling each requirement. Intraoperative adjustment of partial neuromuscular blockade to facilitate TcM-MEP monitoring was also possible with the MCCLIS. The MCCLIS should allow for further investigation into the sensitivity, specificity, and predictability of TcM-MEP monitoring for any patient at risk for intraoperative spinal cord ischemia including those undergoing thoracoabdominal aortic aneurysmectomy.

Action Potentials↗