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Biomedical subjects

K Amaha

Publications and source records attributed to K Amaha.

At least 19 recordsLinked to original sources
PubMed2001

Pulmonary administration of prostacyclin (PGI2) during partial liquid ventilation in an oleic acid-induced lung injury: inhalation of aerosol or intratracheal instillation?

OBJECTIVE: The purpose of this study was to investigate the effects of aerosolized prostacyclin (A-PGI2) and intratracheally instilled prostacyclin (I-PGI2) during partial liquid ventilation (PLV) on gas exchange and pulmonary circulation in rabbits with acute respiratory distress. DESIGN: Prospective control study. SETTING: A research laboratory at a university medical centre. SUBJECTS: Sixty-nine Japanese white rabbits. INTERVENTION: Lung injury was induced by oleic acid and the animals were divided into five groups of ten each: a mechanical gas ventilation (GV) group, an A-PGI2 group, a PLV group, an A-PGI2+PLV group and an I-PGI2+PLV group. PLV, A-PGI2+PLV and I-PGI2+PLV groups received 15 ml/ kg perflubron intratracheally while receiving mechanical GV. A-PGI2 and A-PGI2+PLV groups received aerosolized PGI2 (50 ng/kg/min) in combination with GV or PLV, respectively. The I-PGI2+PLV group was instilled 50 ng/kg/min PGI2 intratracheally in combination with PLV. RESULT: After lung injury, all animals developed hypoxia, hypercarbia and pulmonary hypertension. The improvement of partial pressure of arterial oxygen (PaO2) in the A-PGI2 and PLV groups was transient, whereas the A-PGI2+PLV and I-PGI2+PLV groups showed consistent improvement throughout the experiment. The PaO2 values of the I-PGI2+PLV group were significantly higher than those of the other groups 120 min after treatment. The mean pulmonary artery pressure (PAP) significantly decreased after treatment in the A-PGI2, APGI2+PLV and I-PGI2+PLV groups. CONCLUSIONS: The results suggest that both aerosolized and intratracheally instilled PGI2 improve oxygenation and reduce PAP during PLV in oleic acid lung injury.

Administration, Inhalation↗
PubMed2000

Uptake and elimination of sevoflurane in rabbit tissues--an in vivo magnetic resonance spectroscopy study.

PURPOSE: Previous pharmacokinetic studies of fluorinated anesthetics using 19F-magnetic resonance spectroscopy (19F-MRS) have focused on the brain. Investigation of other tissues would give more precise information about the pharmacokinetics of inhalational anesthetics. In this study we investigated the pharmacokinetics of uptake and elimination of sevoflurane in brain, liver, muscle, venous blood and arterial blood of rabbits. METHODS: Twenty rabbits were examined by 19F-MRS conducted at 4.7 Tesla using a 1-cm-diameter surface coil for brain (n = 4), liver (n = 5) and muscle (n = 5), and a 1.3-cm-diameter surface coil for arterial (n = 3) and venous (n = 3) blood. Sevoflurane, 4% in oxygen, was administered for 120 min, followed by 120 min elimination. RESULTS: Both the uptake and elimination kinetics were best fitted by a biexponential curve which was divided into fast and slow components. During the uptake experiment the time required to reach half of the maximum spectroscopic intensity in each tissue was 1.6 min in arterial blood, 4.7 min in liver, 12.2 min in venous blood, 14.4 min in brain and 20.9 min in muscle. During the elimination experiment the time required to reach half maximum intensity was 2.4 min in arterial blood, 6.3 min in liver, 13.4 min in venous blood, 19.6 min in brain and 28.7 min in muscle. CONCLUSIONS: Sevoflurane uptake or elimination in the tissues examined followed biexponential kinetics. In this rabbit model, sevoflurane uptake and elimination were fastest in arterial blood, followed, in order, by liver, venous blood, brain and muscle.

Anesthetics, Inhalation↗
PubMed2000

Midazolam and ketamine inhibit glutamate release via a cloned human brain glutamate transporter.

PURPOSE: In cerebral ischemia/anoxia, the glutamate transporter runs in reverse and releases glutamate into the extracellular space, causing irreversible neuronal damage. Intravenous anesthetics attenuate overall glutamate release and prevent neuronal injury during anoxia/ischemia, but their effect on the glutamate transporter is variable. METHODS: A human glial glutamate transporter (hGLT-I) cDNA was isolated by screening a human cerebral cortical library. Cloned cDNA was transfected in Chinese hamster ovary cells. The effect of the intravenous anesthetics midazolam (0.3 to 30 microM), ketamine (10 to 100 microM), thiopental (30 to 300 microM), and propofol (3 to 30 microM) on reversed uptake of L-glutamate via hGLT-I was examined by whole-cell patch-clamp. RESULTS: Midazolam at a concentration 3 microM reduced outward currents arising from reversed L-glutamate uptake via hGLT-I in a concentration-dependent manner. While, ketamine at 100 microM attenuated the same outward currents, to 53.3+/-11.4% of those seen in controls without anesthetics (P<0.05, n=5). In contrast, neither thiopental nor propofol showed effects on outward currents mediated by reversed operation of hGLT-I. CONCLUSIONS: These results suggest that midazolam and ketamine, but not thiopental and propofol, have a capacity to inhibit glutamate release via GLT- I directly.

ATP-Binding Cassette Transporters↗
PubMed2000

Effects of mild versus deep hypothermia on a cloned human brain glutamate transporter (GLT-1) expressed in Chinese hamster ovary cells.

Glutamate transporters, widely distributed in the brain and spinal cord, maintain extracellular glutamate concentrations below neurotoxic levels. In cerebral ischemia/anoxia, the glutamate transporter runs in reverse and releases glutamate into the extracellular space, causing irreversible neuronal damage. Although hypothermia reduces the elevation of extracellular glutamate concentration during cerebral ischemia/anoxia, little is known about the effect of hypothermia on the glutamate transporter. A human glial glutamate transporter (hGLT-1) cDNA was isolated by screening a human cerebral cortical library, and cloned cDNA was stably transfected in Chinese hamster ovary (CHO) cells. Effects of deep hypothermia (22 to 23 degrees C) on uptake and release of L-glutamate via hGLT-1 were investigated by whole-cell patch-clamp. The control study was performed at 34 to 35 degrees C. The hGLT-1 transporter had the capacity to take up extracellular L-glutamate under essentially physiological ionic conditions, whereas this transporter promoted release of L-glutamate under a nonphysiological condition mimicking complete ischemia. Deep hypothermia decreased a) uptake and b) release of L-glutamate via hGLT-1 to a) 4.8+/-4.8% (P < .01, n = 7) and b) 19.0+/-4.5% (P < .01, n = 15) of control values, respectively. The results suggest that deep hypothermia is a potent inhibitor of glutamate uptake by intact glial cells as well as glutamate release from glial cells under certain pathophysiological circumstances. The balance between these antagonistic effects of hypothermia may attenuate the elevation of the extracellular glutamate concentration during ischemia/anoxia.

ATP-Binding Cassette Transporters↗
PubMed1999

Laryngeal mask airway insertion using propofol without muscle relaxants: a comparative study of pretreatment with midazolam or fentanyl.

We determined the effects of pretreatment with midazolam or fentanyl on the ease of laryngeal mask airway insertion using propofol without a muscle relaxant. One hundred and eighty ASA class I or II patients were randomly allocated to one of three groups, 60 patients per group, to receive either placebo (Group C), midazolam 0.05 mg kg-1 (Group M) or fentanyl 2 micrograms kg-1 (Group F), respectively. Following intravenous administration of these drugs, Group C received propofol 2.5 (Group C-2.5) or 3.0 mg kg-1 (Group C-3.0). Group M and Group F received propofol 2.0 or 2.5 mg kg-1 (Group M-2.0, M-2.5, F-2.0 and F-2.5, respectively). There was a smaller incidence of severe head and limb movements on LMA insertion in Group M-2.5, Group F-2.0 and Group F-2.5 than in Group C-2.5. Airway obstruction and inadequate jaw relaxation, which were occasionally recognized in Group C and Group F patients, were not observed in Group M-2.5. Overall the ease of LMA insertion was significantly better in Group M-2.0, Group M-2.5 and Group F-2.5 than in Group C-2.5, however, the blood pressure in Group F after LMA insertion was significantly lower than in Group M. We conclude that pretreatment with midazolam 0.05 mg combined with propofol 2.5 mg kg-1 provides safe and satisfactory conditions for LMA insertion.

Adult↗
PubMed1999

The effects of hypothermia on a cloned human brain glutamate transporter (hGLT-1) expressed in Chinese hamster ovary cells: -[3H]L-glutamate uptake study.

UNLABELLED: Hypothermia provides neuroprotection that inhibits increases in extracellular glutamate concentration during ischemia; however, the effect of hypothermia on the glutamate transporter is uncertain. A human glial glutamate transporter (hGLT-1) cDNA, isolated by screening a cDNA, library was cloned and stably transfected into Chinese hamster ovary cells. We assessed the effects of temperature on transporter activity in [3H]L-glutamate flux experiments at 23, 32, and 37 degrees C. Hypothermia of 23 degrees C and 32 degrees C decreased [3H]L-glutamate uptake at 60 min, to 76.7%+/-7.3% (P < 0.05, n = 5) and 70.7%+/-7.5% (P < 0.05, n = 5) of uptake at 37 degrees C, respectively. Reversed uptake of preloaded [3H]L-glutamate via hGLT-1 was not observed at any temperature. The specific uptakes (Q10 values) for 37 degrees C to 32 degrees C and 32 degrees C to 23 degrees C at 30 min were 3.48 and 2.37, whereas they were 2.17 and 0.91, respectively, for 60 min. These changes suggest that hypothermia attenuates uptake of extracellular glutamate via hGLT-1 in a temperature- and time-dependent manner. IMPLICATIONS: Under certain pathologic conditions, including cerebral ischemia and traumatic brain injury, glutamate neurotoxicity may initially be propagated by hypothermia due to relative failure of glutamate uptake via Human Glial Glutamate Transporter before a subsequent recovery of uptake.

ATP-Binding Cassette Transporters↗
PubMed1999

Improvement of renal dysfunction in dogs with endotoxemia by a nonselective endothelin receptor antagonist.

OBJECTIVES: During endotoxemia, there is a marked and intractable decrease in systemic blood pressure, as well as profound vasoconstriction of the renal artery, thereby leading to septic shock and acute renal failure. The purpose of this study was to elucidate the effect of endothelin-1, a potent endothelium-derived vasoconstrictor peptide, on the hemodynamic and renal vascular changes seen in endotoxemia. DESIGN: Prospective, comparative, experimental study. SETTING: Laboratory at a university hospital. SUBJECTS: Thirty-two male mongrel dogs (12.1+/-0.4 kg) under pentobarbital anesthesia. INTERVENTIONS: Four groups of animals were studied: a) the lipopolysaccharide (LPS) group (n = 10), which received LPS (250 ng/kg/min for 2 hrs); b) the TAK-044 (a nonselective endothelinA/ endothelinB receptor antagonist) plus LPS group (n = 12), which received a bolus of TAK-044 (5 mg/kg) 0.5 hr before the start of LPS infusion; c) the TAK-044 plus vehicle group (n = 5), which received the same dose of TAK-044 0.5 hr before the start of vehicle infusion; and d) the control group (n = 5), which received only vehicle infusion. MEASUREMENTS AND MAIN RESULTS: Changes in systemic and renal hemodynamics, blood gas, and renal function were measured at baseline, and at 0.5, 1, 2, 3, and 4 hrs. Infusion of LPS resulted in significant decreases in mean arterial pressure, arterial pH, Pao2, base excess, urine volume, renal blood flow, creatinine clearance, and urine osmolality. The administration of TAK-044 before LPS infusion did not affect the LPS-induced hypotension. In contrast, the receptor antagonist prevented LPS-induced metabolic acidosis and hypoxemia, and improved LPS-induced decreases in urine volume, renal blood flow, creatinine clearance, and urine osmolality, whereas TAK-044 or vehicle administered alone resulted in no significant hemodynamic or blood gas changes. Plasma endothelin-1 concentrations significantly increased after LPS infusion, with or without TAK-044. CONCLUSIONS: The present study suggests that endothelin-1 plays an important role in the impaired renal hemodynamics and renal function associated with endotoxemia, and that endothelin receptor antagonists may be useful as therapeutic agents for acute renal failure during endotoxemia.

Acute Kidney Injury↗
PubMed1999

[A multicenter study for evaluating a new intubating laryngeal mask airway].

A multicenter study was performed to evaluate the success of endotracheal intubation using an intubating laryngeal mask (ILM, Fastrach) in patients in ASA status I or II, aged 20 years or more, who underwent general anesthesia. A total of 191 patients were studied, and 24 of them were estimated difficult to intubate by the ordinary method with laryngoscope. Endotracheal intubation was successfully performed through ILM in 162 of the 191 (success rate of 84.8%). The mean time required for intubation in these successful cases was 19.1 seconds. The success rate did not depend on the clinical experience of anesthesiologists, and the individual success rate was improved as they became more experienced. Of the 24 patients who had been estimated difficult to intubate with laryngoscope, 23 were successfully intubated with success rate of 95.8%. In summary, endotracheal intubation through ILM was easy regardless of the anesthesiologist's experience, and seemed to be valuable for patients who were difficult to intubate.

Adult↗
PubMed1998

Continuous intra-arterial blood gas monitoring during oesophagectomy.

PURPOSE: To evaluate the clinical usefulness of the continuous intra-arterial blood gas (CIABG) monitoring system, Paratrend 7, during differential lung ventilation (DLV) in 12 patients undergoing oesophagectomy. METHODS: Anaesthesia was induced with propofol and was maintained with isoflurane, oxygen and air, supplemented by an epidural infusion of mepivacaine. Arterial samples for estimation of blood gases (ABG) were taken just before and 5, 10, 20, 30, 60, and 90 min after the pleura was opened. The pH, PO2, and PCO2 values displayed by the CIABG monitor, which were recorded prior to the arterial blood sampling, were compared with the results of ABG analysis. RESULTS: Eighty-four blood samples were obtained and the ranges for the measured variables were PCO2 24.8-57.4 mmHg, PO2 47-449 mmHg, and pH 7.30-7.49. The correlation between CIABG and ABG measurements was strong and significant (r values: PCO2 0.80, PO2 0.93, pH 0.94). The overall bias +/- precision between the two methods was PCO2 0.9 +/- 3.1 mmHg, PO2 -1 +/- 40 mmHg, %PO2 0.8 +/- 21.6%, pH 0.00 +/- 0.02. For PO2 values < 150 mmHg, the biases +/- precision were PO2 -5 +/- 17 mmHg, %PO2 -2.1 +/- 20.7%. CONCLUSION: The agreement between CIABG and ABG measurements was better for PCO2 and pH than for PO2. Although the CIABG system is clinically useful for monitoring trends in blood gas changes, the accuracy of the PO2 value may be unacceptable during DLV because the error is theoretically < 34 mmHg with 95% reliability in the clinically important range of PO2, < 150 mmHg.

Anesthesia, Inhalation↗
PubMed1998

Recovery of post-tetanic count and train-of-four responses at the great toe and thumb.

We have studied the recovery of post-tetanic count and train-of-four responses at the great toe and thumb accelerographically after the administration of vecuronium 0.2 mg.kg-1. Sixty adult patients scheduled for anaesthesia with nitrous oxide and isoflurane were studied. The times to the return of the first post-tetanic twitch were comparable at the great toe and thumb (mean (SD) times: 30.0 (6.5) min and 35.0 (8.5) min, respectively). Recovery of post-tetanic count followed similar time courses at the great toe and thumb. Also, time to the return of the first twitch of the train-of-four did not differ significantly at the great toe and the thumb (47.5 (9.6) min vs. 49.7 (10.5) min). Similarly, time to the return of the second, third and fourth twitches of the train-of-four did not significantly differ at the great toe and the thumb. However, the value of the first twitch of the train-of-four, expressed as a proportion of control twitch, was significantly higher than that at the thumb between 50 min and 110 min after the vecuronium injection, and the train-of-four ratio at the great toe was significantly higher than that at the thumb between 60 min and 100 min after the vecuronium injection.

Adult↗
PubMed1998

Post-tetanic burst count and train-of-four during recovery from vecuronium-induced intense neuromuscular block under different types of anaesthesia.

Recovery of neuromuscular blockade after vecuronium 0.2 mg kg-1 was measured by post-tetanic burst count (PTBC) and train-of-four (TOF) in 120 adult patients anaesthetized by one of four techniques: neuroleptanaesthesia or one minimum alveolar concentration of isoflurane, enflurane, or sevoflurane. Onset of recovery was taken when there was reflex movement in response to carinal stimulation. The time course of recovery measured by burst count was similar for all four types of anaesthesia. Recovery of each of the twitches of the TOF was significantly shorter under neuroleptanaesthesia than under isoflurane, enflurane, or sevoflurane anaesthesia [times to return of T1 were 41.4 +/- 5.4, 51.5 +/- 10.6, 52.2 +/- 10.0, or 55.3 +/- 11.2 min (mean +/- SD). P < 0.05]. The burst count at the onset of reflex movement was less under neuroleptanaesthesia than under isoflurane, enflurane, or sevoflurane anaesthesia (16.3 +/- 4.8, 26.7 +/- 6.7, 27.7 +/- 6.8, 28.0 +/- 8.4, P < 0.05). The ratio of first twitch to control twitch at the onset of reflex movement was the same for all four types of anaesthesia.

Adult↗
PubMed1998

Treatment of pulmonary hypertension and hypoxia due to oleic acid induced lung injury with intratracheal prostaglandin E1 during partial liquid ventilation.

BACKGROUND: Partial liquid ventilation using perfluorocarbon liquids may be of therapeutic benefit in patients with acute respiratory failure. This study investigated the effects of prostaglandin E1 (PGE1) delivered intratracheally during partial liquid ventilation on lung function and pulmonary circulation in rabbits with acute respiratory distress syndrome. METHODS: Lung injury was induced by intravenous oleic acid in adult Japanese white rabbits, 1 h after which they were divided into four groups of 10 animals. Group 1 received mechanical ventilation alone, group 2 received aerosolized PGE1 (5 microg followed by 0.1 microg x kg(-1) x min(-1)) under mechanical ventilation combined with 5 cm H2O positive end-expiratory pressure, and groups 3 and 4 received partial liquid ventilation with 15 ml/kg perflubron. Group 4 received a 5-microg bolus followed by 0.1 microg x kg(-1) x min(-1) PGE1 instilled intratracheally (not by aerosol) in combination with partial liquid ventilation. Measurements were performed at 30-min intervals for 120 min after lung injury. RESULTS: After lung injury, hypoxemia, hypercapnia, acidosis, and pulmonary hypertension developed in all animals and were sustained in groups 1 and 2 throughout the experiment. The partial pressure of oxygen in arterial blood of animals in group 3 improved with initiation of treatment, with statistical significance achieved at the 30 and 60 min time points as compared with controls. Group 4 animals had immediate and sustained increases in the partial pressure of oxygen in arterial blood that were significant compared with all other groups during the experiment. Statistically significant reductions in mean pulmonary artery pressure were seen only in group 4 animals compared with all other groups. CONCLUSIONS: These results suggest that PGE1 delivered intratracheally during partial liquid ventilation may be a useful therapeutic strategy for patients with the acute respiratory distress syndrome.

Animals↗
PubMed1998

Accelographic and mechanical post-tetanic count and train-of-four ratio assessed at the great toe.

We examined post-tetanic count (PTC) and train-of-four (TOF) ratios at the great toe assessed accelographically or mechanically and compared these with post-tetanic count and train-of-four ratios evaluated mechanically at the thumb in 24 patients who were given vecuronium. An acceleration transducer was attached to the right great toe, a force transducer to the left great toe and another force transducer to the thumb of the left hand. In the PTC group (n = 12) and TOF group (n = 12), post-tetanic count and train-of-four ratios were simultaneously recorded using the two great toes and the thumb of the left hand respectively. Accelographic post-tetanic count at the great toe was greater than the post-tetanic count at the thumb; however, mechanical post-tetanic count at the great toe was lower than the mechanical post-tetanic count at the thumb. Accelographic and mechanical train-of-four ratios at the great toe were greater than the mechanical train-of-four ratios at the thumb. But mechanical train-of-four ratios at the great toe became similar to mechanical train-of-four ratios at the thumb as the degree of neuromuscular block lessened. In conclusion, the mechanical post-tetanic count at the great toe is lower than the mechanical post-tetanic count at the thumb. In contrast, mechanical train-of-four ratios at the great toe are greater than the mechanical train-of-four at the thumb. Nevertheless, as the mechanical train-of-four ratios at the great toe became comparable with the mechanical train-of-four ratios at the thumb, mechanical assessment of the train-of-four ratio at the great toe may be useful for the evaluation of residual neuromuscular block.

Adult↗
PubMed1998

Pathologic role of endothelin-1 in septic shock.

To elucidate the pathologic role of endothelin-1 (ET-1) in septic shock, we measured plasma ET-1 concentrations after bacterial lipopolysaccharide (LPS) administration in dogs and determined systemic, pulmonary, and renal hemodynamics and blood gas parameters with or without the nonselective ET receptor antagonist TAK-044. Plasma ET-1 concentrations increased significantly after LPS administration, which correlated positively with mean arterial pressure, mean pulmonary arterial pressure, pulmonary capillary wedge pressure, and central venous pressure. LPS infusion induced hypotension, metabolic acidosis, hypoxemia, and renal dysfunction. TAK-044 prevented LPS-induced metabolic acidosis, hypoxemia, and renal dysfunction, but not hypotension. These findings suggest that increased circulating ET-1 plays a compensatory role in the reversal of systemic vasodilatation in septic shock, but exerts deleterious effects on renal and pulmonary circulation.

Animals↗
PubMed1998

Detrimental effect of a non-selective nitric oxide synthase inhibitor on the energy state of the liver following acute endotoxemia in rabbits.

BACKGROUND: The effect of nitric oxide synthase (NOS) inhibitors in septic shock is very controversial. It is known that the administration of NOS inhibitors to normal subjects itself increases pulmonary vascular resistance with a concomitant decrease of cardiac output. Therefore, the hypothesis was tested that the detrimental effects of a non-selective NOS inhibitor on liver energetics in a rodent model of endotoxemia are mediated by the adverse pulmonary circulatory effect of the drug itself. METHODS: Twenty anesthetized rabbits were instrumented and two separate experiments (a magnetic resonance spectroscopic study and a hemodynamic study) were performed under similar conditions. Animals were assigned randomly to either a control group (group 1; animals received lipopolysaccharide (LPS) at a dose of 400 microg/kg alone) or a treatment group (group 2; animals received NG-nitro-L-arginine methyl ester (L-NAME) at a dose of 7.5 mg/kg, 75 min after administration of LPS). RESULTS: In group 1, slight decreases in hepatic adenosine triphosphate (ATP) value were observed. In group 2, the decreases in ATP values were more prominent than those observed in group 1. LPS produced an acute drop in mean arterial pressure (MAP) with a concomitant increase in pulmonary vascular resistance (PVR) and a reduction in the cardiac output (CO) at 30 min after LPS. The administration of L-NAME caused a transient increase in MAP with a concomitant increase in systemic vascular resistance at 2 h after LPS. However, these changes in PVR and CO were more prominent than in group 1. CONCLUSION: These results suggest that alterations within the pulmonary circulation may be a contributing factor which was responsible for the non-selective NOS inhibitor-induced acute hepatic energy derangement after LPS.

Acute Disease↗
PubMed1998

Modified double burst stimulation of varying stimulating currents.

BACKGROUND: Using modified double burst stimulation (modified DBS), sufficient level of recovery from neuromuscular blockade (train-of-four (TOF) ratio > 0.7) can properly be diagnosed. Modified DBS may often be applied in awake patients in the postanesthetic care unit. As the stimulating current decreases, the neurostimulation-induced discomfort becomes less for awake subjects. It is relevant to investigate the usefulness of the modified DBS delivered at low currents. METHODS: One hundred and twenty-one adult patients undergoing nitrous oxide-oxygen-isoflurane anesthesia were randomly divided into one of four groups: group 50 (n = 40), group 30 (n = 40), group 20 (n = 40), and supramaximality group (n = 1). After administration of vecuronium, in one hand and forearm (fixed arm), the degree of neuromuscular blockade was quantified mechanically. In the contralateral arm (free arm), modified DBS stimuli were delivered at 50, 30, and 20 mA in groups 50, 30, and 20, respectively. An observer determined tactilely on the free arm the presence or absence of fade in response to the modified DBS applied at 50, 30, and 20 mA. In one patient (the supramaximality group), modified DBS ratios (D2/D1) were examined at 50, 40, 30, 20, and 10 mA before administration of vecuronium. Moreover, discomfort associated with modified DBS applied at 50, 30, and 20 mA was evaluated using a 10-cm visual analog scale (VAS) in 15 awake volunteers. RESULTS: Probabilities of detection of fade in response to modified DBS in groups 50, 30, and 20 were 90, 86, and 96% (TOF ratios of 0.61-0.70), 62, 73, 94*#% (0.71-0.80), 26, 39, and 79*#% (0.81-0.90), and 4, 33*, and 51*#% (0.91-1.00), respectively. *P < 0.05 as compared to group 50. #P < 0.05 as compared to group 30. Supramaximal responses to D1 and D2 could be elicited at a current > or = 30 mA. The mean VAS scores were 8.7, 6.5*, and 4.1* when stimulated at 50, 30, and 20 mA, respectively. *P < 0.05 as compared to 50 mA. #P < 0.05 as compared to 30 mA. CONCLUSION: Modified DBS-induced discomfort becomes less as the stimulating current decreases. However, when stimulated at 30 or 20 mA, fade in response to modified DBS is felt in too many cases, even after neuromuscular blockage subsides to an adequate level.

Adult↗