Effect of muscle relaxants on heart rate, arterial pressure, intubation conditions and onset of neuromuscular block in patients undergoing valve surgery.
ABSTRACT Sixty six patients undergoing elective valve surgery were randomized to receive rocuronium bromide 0.6 mg/Kg (Group R, n=22), pancuronium bromide 0.1 mg/Kg (Group P, n= 22) and vecuronium bromide 0.1 mg/Kg (Group V, n=22), Measurements of heart rate and arterial pressure (systolic, diastolic and mean) were noted at the following stages: 1) baseline when haemodynamics were stable for 2 minutes after induction of anaesthesia (2) one, (3) three, (4) five minutes after administration of muscle relaxants, (5) One, (6) three, and (7) five minutes after intubation. In group R, the heart rate decreased 5 min after injection of muscle relaxant from 93.9 +/- 21.3 to 82.4 +/- 20.7 beats/min (p<0.001). However, it increased to 128.3 +/- 25.8 beats/min (p<0.001) following intubation and returned to baseline at 5 min after intubation. In group P, heart rate increased from 98.8 +/- 32.6 to 109.6 +/- 32.7 beats/min (p<0.001), 1 min after injection of pancuronium and this increase persisted throughout the study period. In group V, heart rate decreased from 99.9 +/- 22.3 to 83.8 +/-19.6 beats/min (p<0.001) at 5 min after injection of the drug. It increased to 118.6 +/- 22.4 beats/min (p<0.001), 1 min after intubation and returned to baseline at 5 min after intubation. The decrease in heart rate in group R and V was accompanied by a significant decrease in systolic, diastolic and mean arterial pressure. In group P, only the systolic pressure decreased significantly at 5 min after injection of the drug. Intubation was accompanied by a significant increased in systolic, diastolic and mean arterial pressure in all the groups. Excellent intubation conditions (intubation score 3-4) were observed with all the three drugs, however, there were number of patients in group P who showed diaphragmatic movement during intubation. Onset of action of muscle relaxant, was fastest with rocuronium (group R=132.7 +/- 0.3 sec, P=182.6 +/- 68.5 sec, V= 144.8 +/- 46.1 sec, Group P vs Group R). To conclude, pancuronium causes significant increase in heart rate and should be preferred in patients with regurgitant lesions having slower baseline heart rate. Vecuronium and rocuronium decrease the heart rate and should be preferred in patient with faster baseline heart rate. In terms of intubating conditions rocuronium and vecuronium provide best conditions, but onset is faster with rocuronium.
Full-textDOI: · Available from: Vishnu Datt, Feb 07, 2014
- SourceAvailable from: Peter Bergethon[Show abstract] [Hide abstract]
ABSTRACT: Previously we have reported a near-infrared optical response in the region occupied by a peripheral nerve that is distal to the site of electrical stimulation of that peripheral nerve. This "intermediate" signal is vascular in nature but its biological origin not been elucidated. In the present study, an animal model of the signal has been created and our human studies expanded to directly investigate the contribution of non-artifactual vascular motion induced by muscle contraction to the biological origin of this signal. Under non-invasive conditions during stimulation of the exposed sciatic nerve of the Sprague-Dawley rat, optical responses are robust. These signals can be abolished both pharmacologically and surgically using methods that eliminate muscle motion while leaving the electrophysiological health of the nerve intact. In human studies, signals that are elicited on stimulation of nerves containing motor axons, both within and outside the predicted imaging volume of the spectrometer, have similar temporal characteristics of those previously observed. Moreover, stimulation of sensory nerves alone does not elicit an optical response. These results strongly suggest that the intermediate signals are derived from stimulus-induced muscle contraction (whether via an innervating nerve or by direct stimulation) causing translational vascular motion within the optically interrogated region.Biomedical Optics Express 10/2010; 1(3):943-954. DOI:10.1364/BOE.1.000943 · 3.50 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: We have previously reported an optical response in human subjects occurring at 100 ms following electrical stimulation of peripheral nerves. In the present study, an animal model has been created to directly investigate the myogenic components of the signal. In addition, experiments have been performed in human subjects to investigate the signal's neuroanatomical specificity, sensitivity to muscle motion, and spatial and spectral features. The results of this work suggest that the observed optical signal derives from stimulus-induced motion associated with muscle contraction and likely contains myological information of clinical value.Proceedings - Society of Photo-Optical Instrumentation Engineers 01/2011; 7896(1). DOI:10.1117/12.875145