Biomedical subjects

H Toyooka

Publications and source records attributed to H Toyooka.

At least 127 records · Page 7Linked to original sources

PubMed1997

Evaluation of residual neuromuscular blockade using modified double burst stimulation.

BACKGROUND: To assess the degree of residual neuromuscular blockade, double burst stimulation (DBS) is commonly applied in the clinical setting. However, fades in response to DBS3,3 can rarely be identified manually when train-of-four (TOF) ratios are > or = 0.70, and, in contrast, fades in response to DBS3,2 are felt manually in an undesirably high proportion of cases, even at TOF ratios greater than 0.7. We investigated whether a new monitoring method, modified DBS, would be useful to determine an adequate degree of recovery from neuromuscular blockade. For modified DBS, two burst stimuli were applied at an interval of 750 ms. The first stimulation in the modified DBS consisted of two stimuli of 0.3 ms duration at 50 Hz and the second of two stimuli of 0.2 ms duration at 50 Hz. METHODS: Forty-five adult patients undergoing elective nitrous oxide-oxygen-isoflurane anesthesia were randomly divided into one of three groups: DBS3,3 group (n = 15), DBS3,2 group (n = 15), or modified DBS group (n = 15). During recovery from vecuronium-induced neuromuscular blockade, on both forearms, DBS3,3, DBS3,2, and modified DBS were delivered in the DBS3,3 group, DBS3,2 group, and modified DBS group, respectively. One hand and forearm (fixed arm) were immobilized to quantify the degree of neuromuscular blockade mechanically, and the contralateral arm (free arm) was unrestrained. An observer determined tactiley on the free arm the presence or absence of fade in response to the three DBS patterns. RESULTS: Probabilities of detection of fade in response to the DBS3,3 were 67% (TOF ratio of 0.51-0.60), 40% (0.61-0.70), 19% (0.71-0.80), 5% (0.81-0.90), and 0% (0.91-1.00). Those to the DBS3,2 were 95% (0.51-0.60), 93% (0.61-0.70), 83% (0.71-0.80), 65% (0.81-0.90), and 38% (0.91-1.00). Those to modified DBS were 90% (0.51-0.60), 86% (0.61-0.70), 65% (0.71-0.80), 25% (0.81-0.90), and 3% (0.91-1.00). Those modified DBS was more sensitive in diagnosing residual neuromuscular blockade than DBS3,3 at the TOF ratio of 0.51-0.90, but was less sensitive than DBS3,2 at the TOF ratio of 0.81-1.00 (P < 0.05). CONCLUSION: Our results indicate that the modified DBS may be a useful stimulation pattern to diagnose the adequacy of recovery from neuromuscular blockade.

Adult↗

PubMed1997

Granisetron reduces incidence of nausea and vomiting after breast surgery.

BACKGROUND: Postoperative nausea and vomiting (PONV) remains a troublesome problem. The study was performed to evaluate the antiemetic efficacy of prophylactic granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, on the incidence of PONV in patients undergoing general anaesthesia for breast surgery. METHODS: In a randomized, placebo-controlled, double-blind study, 50 female patients, 45-68 years, were given a single dose of either placebo (saline, n = 25) or granisetron (40 micrograms.kg-1, n = 25) intravenously over 2-5 min immediately before the induction of anaesthesia. Postoperatively, during the first 24 hours after anaesthesia, the incidence of PONV and adverse events was recorded. RESULTS: The treatment groups were similar for patient demographics, types of surgery, anaesthetic and postoperative management. Postoperatively, the incidence of PONV was 48% and 16% after administration of placebo and granisetron, respectively (P < 0.05). No differences in the incidence of other adverse events were observed between the two groups. CONCLUSION: Granisetron is an effective antiemetic for preventing PONV in patients undergoing general anaesthesia for breast surgery.

Aged↗

PubMed1997

Effective dose of granisetron in the reduction of nausea and vomiting after breast surgery.

BACKGROUND: Prophylactic use of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, reduces the incidence of nausea and vomiting after breast surgery. This study was undertaken to determine the minimum effective dose of granisetron in the reduction of postoperative nausea and vomiting (PONV) in patients undergoing general anaesthesia for breast surgery. METHODS: In a randomized, double-blind manner, 120 female patients aged 42-66 years were assigned to receive either placebo (saline) or granisetron in a dose of 20 micrograms.kg-1, 40 micrograms.kg-1 and 80 micrograms.kg-1 i.v. immediately before the induction of anaesthesia. A standard general anaesthetic technique was employed throughout. The PONV and safety assessments were performed continuously during the first 24 h after anaesthesia. RESULTS: There were no significant differences among the groups with regard to patient demographics, surgical procedures, anaesthetics administered and analgesics given. The incidence of PONV was 47%, 43%, 17% and 17% after administration of placebo and granisetron 20 micrograms.kg-1, 40 micrograms.kg-1 and 80 micrograms.kg-1, respectively. Granisetron 40 micrograms.kg-1 was as effective as 80 micrograms.kg-1 and both resulted in significant reductions of the incidence of PONV compared with placebo and granisteron 20 micrograms.kg-1 (P < 0.05). No differences in the incidence of adverse events were observed among the groups. CONCLUSION: Granisetron 40 micrograms.kg-1 appears to be the minimum effective dose for reducing PONV in patients undergoing general anaesthesia for breast surgery.

Adult↗

PubMed1997

[Anesthetic management of parturients with intracranial arteriovenous malformation].

We have retrospectively analyzed twelve pregnancies in nine patients with intracranial arteriovenous malformation (AVM) managed at our hospital from 1984 to 1995. Following radical excision of AVM before or during pregnancy in 6 cases, transvaginal deliveries were performed without untoward sequelae. In three of five patients who received non-curative treatments, labor analgesia was provided using epidural local anesthetics. One patient who presented with ruptured AVM followed by medical therapy, elective cesarean section was performed under spinal anesthesia with a favorable outcome. Anesthesia courses in two patients for the resection of ruptured AVM during pregnancy were uneventful under enflurane and nitrous oxide anesthesia, or balanced anesthesia using fentanyl and nitrous oxide in oxygen. Simultaneous cesarean section craniotomy was not performed at our hospital.

Analgesia, Obstetrical↗

PubMed1997

[Pre- and post-operative management of cesarean section in a parturient with severe preeclampsia accompanied by hyperdynamic state].

A 37-year-old parturient with severe preeclampsia accompanied by pulmonary edema underwent emergency cesarean section. Pulmonary artery (PA) catheter inserted while the patient was awake revealed hyperdynamic state with increased cardiac index and preload, and decreased systemic vascular resistance. Epidural anesthesia and analgesia were provided with a satisfactory outcome. Monitoring of PA pressure and cardiac index was continued postoperatively in ICU for fluid management. We conclude that preoperative PA catheterization provides useful hemodynamic information in severe preeclamptic patients associated with persistent oliguria, pulmonary edema and hyperdynamic state.

Adult↗

PubMed1996

Inhaled nitric oxide improved the outcome of severe right ventricular failure caused by lipopolysaccharide administration.

OBJECTIVE: To evaluate the efficacy of nitric oxide (NO) inhalation against endotoxin-induced lung injury. DESIGN: Randomized prospective short-term study. SETTING: University school of Medicine Laboratory. INTERVENTIONS: Animal experiment (using 16 Japanese white rabbits). The animals inhaled NO at a concentration of 10 ppm. MEASUREMENTS AND RESULTS: The rabbits were randomly divided into the NO inhaling group (n = 7) and the control group (n = 9). Both groups received continuous infusion of 1200 mcg lipopolysaccharide (LPS) and the NO group inhaled 10 ppm NO during the LPS administration. In the control group, severe right ventricular (RV) failure was observed at 30-90 min of LPS infusion, and 4 of 9 animals died within 90 min of LPS infusion. In the NO group, none of the animals died and the early phase hemodynamic deterioration was milder than in the control group. But pulmonary gas exchange was not significantly different between the two groups throughout the study. At the end of the study there were no significant differences in any parameters of the surviving animals between the two groups. CONCLUSION: Although an improvement of pulmonary gas exchange was not demonstrated, NO inhalation (10 ppm) improved the outcome of severe RV failure caused by LPS infusion.

Analysis of Variance↗

PubMed1996

Antiemetic effects of granisetron on postoperative nausea and vomiting in patients with and without motion sickness.

PURPOSE: This randomized, placebo-controlled, double-blind study was to evaluate the effects of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, for preventing postoperative nausea and vomiting in 110 patients with (n = 50) and without (n = 60) a history of motion sickness undergoing general anaesthesia for major gynaecological surgery. METHODS: The patients received a single dose of either granisetron (40 micrograms.kg-1) or placebo (saline) iv over 2-5 min immediately before induction of anaesthesia. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of nausea and vomiting were recorded. RESULTS: Except for a positive history of motion sickness, the treatment groups were similar for patient characteristics, types of surgery, anaesthetics administered and opioids given. Postoperatively, the frequency of nausea was 44% and 16% after administration of placebo and granisetron in patients with motion sickness, and was 30% and 7% in patients without it, respectively; the corresponding frequencies of vomiting were 28%, 8%, 13% and 3%. The incidence of adverse events postoperatively were not different among the groups. CONCLUSION: These results suggest that preoperative prophylactic administration of granisetron is effective and safe for preventing postoperative nausea and vomiting in patients with motion sickness as well as in patients without it.

Adult↗

PubMed1996

Recovery of post-tetanic and train-of-four responses at the first dorsal interosseous and adductor pollicis muscles in patients receiving vecuronium.

PURPOSE: To compare recovery of accelographical responses to post-tetanic twitch (PTT) and train-of-four (TOF) stimuli obtained at the first dorsal interosseous muscle (DI) with those at the adductor pollicis muscle (AP) after administration of vecuronium 70 micrograms.kg-1. METHODS: Sixty adult patients were randomly assigned to one of four groups: PTT-DI (n = 15), PTT-AP (n = 15), TOF-DI (n = 15), or TOF-AP (n = 15) group. In PTT-DI and PTT-AP groups, responses to PTT were measured accelographically at the DI and at the AP, respectively. In TOF-DI and TOF-AP groups, responses to TOF were measured at the DI and at the AP, respectively. RESULTS: The T1/T0 (T0 = control) was greater in the TOF-DI than in TOF-AP group throughout recovery (P < 0.05), and the T4/T1 was greater in the TOF-DI than in TOF-AP group during the 30-40 min after vecuronium injection (P < 0.05). Time to the return of the first response to PTT (post-tetanic count(1), PTC1) was less in the PTT-DI than in the PTT-AP group (17.7 +/- 4.2 vs 21.7 +/- 5.6 min, mean +/- SD, P = 0.0341). The post-tetanic count PTC (number of single twitch stimuli in response to PTT) was greater in the PTT-DI than in the PTT-AP group during the 10-30 min after vecuronium (P < 0.05). Time to the return of T1 was less in the TOF-DI than in the TOF-AP group (23.1 +/- 6.0 vs 27.6 +/- 4.9 min, P = 0.0334). CONCLUSION: Recovery of responses to PTT and TOF stimuli occurred earlier at the DI than at the AP.

Adult↗

PubMed1996

Antiemetic efficacy of granisetron and metoclopramide in children undergoing ophthalmic or ENT surgery.

PURPOSE: The purpose of this study was to compare the effectiveness of granisetron, metoclopramide and placebo in reducting the frequencies of retching and vomiting in children who had undergone strabismus repair and tonsillectomy with or without adenoidectomy. METHODS: In a randomized, double-blind study, 70 healthy subjects, 4-10 yr of age, were given a single dose of either placebo (saline, n = 24), metoclopramide 0.25 mg.kg-1 (n = 23) granisetron 40 micrograms.kg-1 (n = 23) iv over two to five minutes after the induction of anaesthesia. All subjects received inhalation anaesthesia with sevoflurane and nitrous oxide in oxygen. Rescue antiemetics were administered if two or more episodes of vomiting occurred. Acetaminophen pr or pentazocine iv was given as needed for postoperative pain. All subjects remained in hospital for two days. During the first three and the next 21 hr after anaesthesia, the frequencies of retching and vomiting were recorded by nursing staff. RESULTS: There was no difference among groups with regard to demographic characteristics, surgical procedures, anaesthetics administered, postoperative managements, or adverse effects. During 0-3 hr after anaesthesia, the frequencies of retching and vomiting were: placebo 62%, metoclopramide 22% and granisetron 13% (P < 0.05). The corresponding frequencies during 3-24 hr after anaesthesia were: placebo 50%, metoclopramide 39% and granisetron 13% (P < 0.05). Four children who had received placebo and three who had received metoclopramide required another rescue antiemetic. CONCLUSION: Granisetron 40 micrograms.kg-1 is more effective than either metoclopramide or placebo in reducing the frequencies of postoperative retching and vomiting during the first 24 hr after anaesthesia in children who have undergone strabismus surgery and tonsillectomy with or without adenoidectomy.

Adenoidectomy↗

PubMed1996

Double burst stimulation2,3: a new stimulating pattern for residual neuromuscular block.

PURPOSE: We present a new stimulating pattern: double burst stimulation2,3 (DBS2,3) for evaluating residual neuromuscular block. METHODS: Forty adult patients were studied. For DBS2,3, two burst stimuli were applied every 750 msec. The first consisted of two tetanic stimuli of 0.2 msec duration and the second of three tetanic stimuli of 0.2 msec duration. At varying degrees of neuromuscular block induced by vecuronium, the presence or absence of fade, or the presence or absence of waxing (i.e., the feeling that the muscular contraction in response to the second burst was stronger than that to the first) was determined by an observer blinded to the depth of neuromuscular block. In addition, the relationship between the train-of-four (TOF) ratio and DBS2,3 ratio was established at varying depths of neuromuscular block (TOF ratio 0.04-1.00). RESULTS: The probabilities of tactile detection of fade in response to DBS2,3 were 100, 76, 15, 9, 3, 0, and 0% at a TOF ratio of 0-0.40, 0.41-0.50, 0.51-0.60, 0.61-0.70, 0.71-0.80, 0.81-0.90, and 0.91-1.00, respectively. Waxing in response to the DBS2,3 was identified in 0, 6, 32, 84, and 98% of cases when the TOF ratios were 0.00-0.60, 0.61-0.70, 0.71-0.80, 0.81-0.90, and 0.91-1.00, respectively. A close linear relationship existed between the TOF ratio and DBS2,3 ratio (r = 0.96, P < 0.000001). CONCLUSION: DBS2,3 is of clinical use because when residual neuromuscular block is clinically important, fade can be identified, but once neuromuscular function returns to a sufficient level, waxing can be detected.

Adult↗

PubMed1996

Granistron and dexamethasone provide more improved prevention of postoperative emesis than granisetron alone in children.

PURPOSE: Dexamethasone decreases chemotherapy-induced emesis when added to antiemetic regimens. This study was designed to compare the effectiveness of granisetron and dexamethasone with granisetron alone in the prevention of post-operative vomiting after strabismus repair, tonsillectomy with or without adenoidectomy in children. METHODS: In a randomized, double-blind study, 60 healthy children, 4-10 yr of age, received either granisetron 40 micrograms.kg-1 and saline (Group S) or granisetron 40 micrograms.kg-1 and dexamethasone 4 mg (Group D) iv immediately after the induction of anaesthesia. All subjects received anaesthetics consisting of sevoflurane and nitrous oxide in oxygen Postoperative pain was treated with acetaminophen pr or pentazocine iv. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of retching and vomiting, and the incidence of adverse events were recorded by nursing staff. RESULTS: There were no differences between the treatment groups with regard to demographics, surgical procedure, anaesthetic administered or analgesics used for postoperative pain. The frequency of the symptoms was 27% and 7% in Groups S and D, respectively (P < 0.05). The incidence of adverse events was comparable in the two groups. CONCLUSION: The prophylactic administration of granisetron and dexamethasone was more effective than granisetron alone in the prevention of postoperative vomiting in paediatric subjects undergoing strabismus repair, tonsillectomy and adenoidectomy.

Antiemetics↗

PubMed1996

Granisetron reduces vomiting after strabismus surgery and tonsillectomy in children.

PURPOSE: To evaluate the antiemetic efficacy of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, on postoperative vomiting in children undergoing general anaesthesia for strabismus repair and tonsillectomy with or without adenoidectomy. METHODS: In a randomized, placebo-controlled, double-blind study, fifty patients, 4-10 yr of age, were given a single dose of either placebo (saline, n = 25) or granisetron (40 micrograms.kg-1, n = 25) iv over 2-5 min after the induction of anaesthesia and prior to the surgical procedure. Postoperatively, during the first 24 hr after anaesthesia, the frequencies of retching and vomiting were recorded. RESULTS: There were no differences between the two groups with regard to patient characteristics, surgical procedures and anaesthetic or postoperative management. The incidence of retching was 36% and 12% after administration of placebo or granisetron, respectively (P < 0.05); the corresponding frequencies of vomiting were 32% and 8% (P < 0.05). Four children who had received placebo required another rescue antiemetic drug, whereas none who had received granisetron needed this agent. CONCLUSION: Granisetron is effective in the prevention of retching and vomiting after strabismus repair and tonsillectomy in paediatric patients.

Antiemetics↗

PubMed1996

Effective dose of granisetron for preventing postoperative emesis in children.

PURPOSE: This study was to identify the minimum effective dose of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, to prevent postoperative vomiting in children who have undergone strabismus repair, tonsillectomy or tonsillectomy with adenoidectomy. METHODS: In a randomized, double-blind fashion, 80 healthy children aged 4-10 yr were assigned to receive either placebo (saline) or granisetron in a dose of 20, 40 or 80 micrograms.kg-1 iv immediately following the induction of anaesthesia. All subjects received a standardized anaesthetic, which consisted of sevoflurane in nitrous oxide and oxygen. Rescue antiemetics were administered if two or more episodes of vomiting occurred. Postoperative pain was treated with acetaminophene pr or pentazocine iv. During the first 24 hr after anaesthesia, the frequencies of retching and vomiting were recorded in a standardized fashion by nursing staff while subjects were in a hospital. RESULTS: There were no differences among four treatment groups with regard to subject characteristics, surgical procedures, anaesthetic and postoperative management or adverse effects. The frequencies of these symptoms were as follows: 65%, 60%, 20% and 15% after administration of placebo, granisetron 20, 40 or 80 micrograms.kg-1. Three children who had received either placebo or granisetron 20 micrograms.kg-1 required another rescue antiemetic drug, whereas none who had received granisetron 40 or 80 micrograms.kg-1 needed rescue drugs. CONCLUSION: Granisetron 40 micrograms.kg-1 is an effective antiemetic for preventing retching and vomiting following strabismus repair and tonsillectomy in children. Increasing the dose to 80 micrograms.kg-1 provided no demonstrable benefit in reducing postoperative emesis.

Antiemetics↗

PubMed1996

Intraoperative ventilation with air and oxygen during laparoscopic cholecystectomy decreases the degree of postoperative hypoxaemia.

We studied the effects of intraoperative use of air in oxygen (O2) (FiO2 = 0.33) versus nitrous oxide (N2O) in O2 (FiO2 = 0.33) on the degree of postoperative hypoxaemia in 30 patients undergoing laparoscopic cholecystectomy. Patients were randomly allocated to receive either general anaesthesia with air (Group A, n = 15) or with N2O (Group N, n = 15). Arterial gas tensions were measured before, 24 h and 48 h after surgery while breathing room air. The mean PaO2 24 h and 48 h postoperatively decreased significantly in both groups compared with the preoperative values. The mean PaO2 24 h postoperatively in Group N (74.6 +/- 6.4 mmHg) tended to be lower than that in Group A (78.1 +/- 8.3 mmHg). The mean PaO2 48 h postoperatively in Group N (75.0 +/- 7.8 mmHg) was significantly lower than that in Group A (83.5 +/- 7.9 mmHg) (P < 0.05). On the contrary, the mean PaCO2 did not show any significant change during 48 h postoperatively in either group. Our results suggest that ventilation with N2O and O2 during laparoscopic cholecystectomy is associated with a lower degree of postoperative hypoxaemia.

Adult↗

PubMed1995

Circulatory responses to laryngeal mask airway insertion or tracheal intubation in normotensive and hypertensive patients.

The effects of laryngeal mask airway (LMA) insertion and tracheal intubation on circulatory responses were studied in normotensive (n = 24) and hypertensive (n = 22) patients. In a randomized, double-blind manner, LMA insertion or tracheal intubation was performed after induction of anaesthesia with thiopentone and muscle relaxation with succinylcholine. In both normotensive and hypertensive patients, heart rate (HR), mean arterial pressure (MAP) and rate-pressure product increased after tracheal intubation or LMA insertion compared with baseline (P < 0.05). The haemodynamic changes were greater after intubation than after LMA insertion (P < 0.05). Following intubation of the trachea or insertion of the LMA, HR increased more markedly in hypertensive patients than in normotensive patients (P < 0.05). Plasma adrenaline and noradrenaline concentrations after tracheal intubation or LMA insertion increased compared with baseline values (P < 0.05) in normotensive and hypertensive patients. The increase in noradrenaline concentration after tracheal intubation was greater than that after LMA insertion (P < 0.05). No patient revealed ECG evidence of myocardial ischaemia. We conclude that insertion of LMA is associated with less circulatory responses than tracheal intubation in both normotensive and hypertensive patients.

Adult↗

PubMed1995

Amrinone improves contractility of fatigued diaphragm in dogs.

The effects of amrinone, a bipyridine derivative, on diaphragmatic contractility and fatigue were examined in 36 anaesthetized, mechanically ventilated dogs divided into four groups. In Group Ia (n = 8), dogs without diaphragmatic fatigue were given a bolus injection (0.75 mg.kg-1) followed by continuous infusion (10 micrograms.kg-1.min-1) of amrinone iv. In Group Ib (n = 8), animals without fatigue received infusion only of maintenance fluid. In Group IIa (n = 10) and Group IIb (n = 10), diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. After producing fatigue, amrinone (0.75 mg.kg-1 loading dose plus 10 micrograms.kg-1.min-1 maintenance dose) iv were administered in Group IIa. Only maintenance fluids were administered in Group IIb during this period. Diaphragmatic contractility was assessed in each group by measuring transdiaphragmatic pressure (Pdi). Compared with Group Ib, Pdi at any stimuli in Group Ia did not differ. After producing fatigue, in Group IIa and Group IIb, Pdi decreased at low-frequency (10-30 Hz) stimulation (P < 0.05), whereas no change in Pdi was observed at high-frequency (50-100 Hz) stimulation. In Group IIa, Pdi to each stimulus increased during amrinone infusion compared with Group IIb (p < 0.05). In Group IIb, the speed of recovery from fatigue was relatively slower at low-frequency stimulation. The integrated diaphragmatic electric activity (Edi) did not change throughout the experiment. These results indicate that amrinone improves contractility in the fatigued diaphragm.

Amrinone↗

PubMed1995

Prevention of postoperative nausea and vomiting with granisetron: a randomized, double-blind comparison with droperidol.

The effects of granisetron for preventing postoperative nausea and vomiting were investigated in a randomized, double-blind comparison with droperidol and placebo in 100 patients undergoing general anaesthesia for major gynaecological surgery. The patients received a single dose of either granisetron (40 micrograms x kg(-1), n = 25), droperidol (1.25 mg, n = 25; 2.5 mg n = 25) or placebo (saline, n = 25)iv over two to five minutes immediately before induction of anaesthesia. The antiemetic effects of these drugs were evaluated during the first three and the next 21 hr after recovery from anaesthesia. During 0-3 hr after anaesthesia, the frequency of nausea and vomiting was 60%, 12%, 16% and 12% after administration of placebo, granisetron, droperiodol 1.25 mg or droperidol 2.5 mg, respectively. The corresponding frequencies during 3-24 hr after anaesthesia were 44%, 8%, 36% and 12%. The efficacy of granisetron in preventing postoperative nausea and vomiting was almost equal to that of droperidol 2.5 mg. The awakening time in the patients who had received droperidol 2.5 was prolonged by approximately three minutes compared with the placebo group (P <0.05), and postoperative drowsiness/sedation was observed in these patients. In conclusion, preoperative prophylactic administration of granisetron is superior to that of droperidol in the prevention of postoperative nausea and vomiting after anaesthesia.

Adult↗

PubMed1995

Optimal stimulating current for train-of-four stimulation in conscious subjects.

The purpose of this study was to determine the optimal stimulating current for train-of-four (TOF) monitoring with regard to the return of TOF response and the discomfort associated with TOF. Two variables were examined at 60, 50, 40, 30, and 20 mA: (1) times from administration of vecuronium 80 micrograms.kg-1 to returns of responses to TOF determined accelographically in 75 anaesthetised patients and (2) discomfort associated with TOF in 15 awake volunteers using visual analogue scale (VAS). Times to return of the first response to stimulation at 60, 50, 40, and 30 mA were not different (29.1 +/- 11.2, 30.1 +/- 12.0, 31.9 +/- 12.6, and 35.4 +/- 14.2 min, respectively, mean +/- SD). However, time to the return of the first response elicited at 20 mA (53.7 +/- 21.6) was longer than at higher currents (P < 0.05). Similarly, with regard to the second, third, and fourth responses, the time to the return at 20 mA was longer than at the other currents (P < 0.05). The VAS associated with TOF at 60, 50, 40, 30, and 20 mA were 7.3 +/- 1.9, 6.7 +/- 1.8, 6.0 +/- 2.0, 4.1 +/- 2.1, and 2.7 +/- 2.3, respectively. The VAS at 30 mA was less than at 60 and 50 mA (P < 0.05), and at 20 mA was less than at 60, 50, and 40 mA (P < 0.05). In conclusion it is suggested that, when testing conscious patients, 30 mA is the optimal stimulating current for TOF monitoring because it represents the best compromise of neuromuscular monitoring and patient discomfort.

Adult↗