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Biomedical subjects

S Sakura

Publications and source records attributed to S Sakura.

At least 37 records · Page 2Linked to original sources
PubMed1998

Anaesthetic management of caesarean section in a patient with myelodysplastic syndrome.

PURPOSE: This case report describes the anaesthetic management for Caesarean section in a patient with myelodysplastic syndrome. CLINICAL FEATURES: A woman with myelodysplastic syndrome underwent Caesarean section on two occasions. The first Caesarean section was performed at age 20 yr using general anaesthesia with nitrous oxide-oxygen and fentanyl. In her second pregnancy at 25 yr, there was severe pancytopenia at 28-wk gestation with a leukocyte count 3.6 x 10(9).L-1, erythrocyte count 1.2 x 10(12).L-1, haemoglobin 50 g.L-1, haematocrit 14.7% and platelet count 51 x 10(9).L-1. Following leukocyte poor red cells and platelet transfusion, general anaesthesia was maintained with nitrous oxide-oxygen-sevoflurane and fentanyl. Both operations were uneventful and healthy infants were delivered. CONCLUSION: It is important to have a team approach (anaesthetist, obstetrician and haematologist) for the perianaesthetic management of patients with myelodysplastic syndrome. An exact assessment of the haematological condition, the need for prophylactic treatment and anaesthetic management should be determined for each individual patient.

Adult↗
PubMed1998

Quantitative and selective assessment of sensory block during lumbar epidural anaesthesia with 1% or 2% lidocaine.

We have examined sensory block during lumbar epidural anaesthesia using a cutaneous current perception threshold (CPT) sensory testing device in 20 patients who received 10 ml of either 1% or 2% lidocaine (lignocaine). CPT at 2000, 250 and 5 Hz stimulation at the trigeminal (V), ninth thoracic (T9) and second lumbar (L2) dermatomes, and dermatomal levels of block to light touch, temperature and pinprick discrimination were measured before and every 5 min until 60 min after epidural lidocaine. There were significant differences between 1% and 2% epidural lidocaine in all CPT at T9 and L2, in addition to maximal cephalad spread of the three sensory modalities. After 2% lidocaine, all CPT increased significantly at T9 and L2. In contrast, only at 250 and 5 Hz for L2 did epidural block with 1% lidocaine produce significant increases in CPT. Maximal level of loss of touch sensation after 1% lidocaine was significantly lower than that of cold and pinprick sensations. We conclude that the dose of lidocaine affected intensity of sensory block during lumbar epidural anaesthesia. In addition, differential neural block resulting from epidural anaesthesia appeared to be associated with a differential effect on nerve fibres of different sizes.

Adult↗
PubMed1998

Antinociceptive effects of intrathecal L-type calcium channel blockers on visceral and somatic stimuli in the rat.

UNLABELLED: L-type calcium channels can modulate neuronal transduction in the spinal cord. However, their role in noxious information processing in animals that are physiologically intact has not been elucidated. We evaluated the effects of L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception at the level of the spinal cord. Intrathecal catheters were inserted at the L4-5 level in Sprague-Dawley rats. The tail flick (TF) test and colorectal distension (CD) test were used to assess somatic and visceral antinociceptive effects, respectively. Motor function was assessed by posture and muscle tone in the limbs. TF latency and CD threshold were measured before and for 180 min after the intrathecal administration of verapamil (50, 100, 300, and 500 microg), diltiazem (100, 300, 500, and 1000 microg), or isotonic sodium chloride solution. The percent maximal possible effect (%MPE) was calculated by transforming response threshold in TF and CD tests. Intrathecally administered diltiazem or verapamil increased both TF latency and CD threshold in a dose-dependent fashion. Isotonic sodium chloride solution, diltiazem 100 microg, and verapamil 50 microg did not increase %MPE in either test. Diltiazem 300 or 500 microg or verapamil 300 or 500 microg significantly (P < 0.05) increased %MPE, with the peak effects 5 min after administration and short-duration antinociception. %MPE was 100% until 15 min after the administration of diltiazem 1000 microg, and significant antinociception continued until 180 min in the TF test. Motor paralysis was observed after the administration of the larger dose of each drug. We demonstrated that intrathecally administered L-type calcium channel blockers diltiazem or verapamil produced both somatic and visceral antinociception and motor block dose-dependently. IMPLICATIONS: We examined the effects of intrathecally administered L-type calcium channel blockers diltiazem and verapamil on somatic and visceral nociception in rats. L-type calcium channel blockers produced antinociceptive effects, suggesting a possible clinical application to control pain.

Analgesics↗
PubMed1998

Interaction of intrathecally infused morphine and lidocaine in rats (part I): synergistic antinociceptive effects.

BACKGROUND: Synergistic antinociception of opioids and local anesthetics has been established in bolus injections but not in long-term use. The somatic and visceral antinociceptive effects of intrathecally infused morphine or lidocaine were characterized, and the nature of the interaction of those agents in rats was evaluated. METHODS: Intrathecal catheters were implanted in rats. Morphine (0.3 to 10 microg x kg(-1) x h(-1)), lidocaine (30-1,000 microg x kg(-1) x h(-1)), a combination of those, or saline was infused intrathecally at a constant rate of 1 microl/h for 6 days. The tail flick and colorectal distension tests were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests and motor function tests were repeated on days 1, 2, 3, 4, and 6. Isobolographic analysis was performed on the results of the tail flick test to determine the magnitude of the interaction. RESULTS: Intrathecally infused morphine produced dose-dependent antinociceptive effects in both the tail flick and the colorectal distension tests. Morphine showed a lower peak percentage maximum possible effect (%MPE) in the colorectal distension test than in the tail flick test. Intrathecal lidocaine also produced dose-dependent antinociceptive effects. Lidocaine infusion at 1,000 microg x kg(-1) x h(-1) caused motor impairment. Coinfusion of morphine 0.3 microg x kg(-1) x h(-1) and lidocaine 200 microg x kg(-1) x h(-1), which had no effects by themselves, significantly increased the percentage maximum possible effects (P < 0.01). Coinfused lidocaine potentiated the duration and the magnitude of morphine antinociception. Isobolographic analysis of the tail flick test on day 1 showed a synergistic interaction between morphine and lidocaine. CONCLUSIONS: Morphine and lidocaine intrathecally coadministered synergistically potentiated the antinociceptive effects of each other. That coinfusion dramatically potentiated visceral antinociception, whereas the infusion of morphine alone showed little visceral antinociception.

Analgesics↗
PubMed1998

Interaction of intrathecally infused morphine and lidocaine in rats (part II): effects on the development of tolerance to morphine.

BACKGROUND: There has been little information regarding the effects of local anesthetics on tolerance to opioids, although chronic use of combination of opioids and local anesthetics is popular for pain control. This study was designed to examine the effects of lidocaine on morphine tolerance to somatic and visceral antinociception. METHODS: Rats received a continuous intrathecal infusion of morphine (0.3-10 microg x kg(-1) x h(-1)), lidocaine (30-1000 microg x kg(-1). h(-1)), a combination of those, or saline. After 6- day infusion, intrathecal morphine challenge test (5 microg/10 microl) was performed, and time-response curve was constructed to assess the magnitude of tolerance. The tail flick (TF) test and colorectal distension (CD) test were used to measure somatic and visceral antinociceptive effects, respectively. RESULTS: Antinociceptive effects in the TF and CD tests caused by morphine challenge were reduced (P < 0.01) in the morphine infused groups. The magnitude of the tolerance was inversely associated with the amount of morphine infused. Lidocaine infusion induced no different change in the morphine challenge test from that seen in the saline infusion group. Development of tolerance was greater in morphine 3 microg x kg(-1) h(-1) than in morphine 0.75 microg x kg(-1) x h(-1) + lidocaine 150 microg x kg(-1) x h(-1) despite their similar antinociceptive effects during intrathecal infusion. The infusion of a low dose of morphine (0.3 microg kg(-1) x h(-1)) did not reduce the antinociceptive effects in the challenge test. CONCLUSION: Lidocaine in combination with morphine does not reduce tolerance to morphine nor develop cross-tolerance. The intrathecal infusion of morphine induced tolerance to somatic and visceral antinociception in a dose-dependent fashion.

Analgesics↗
PubMed1998

[Quantitative assessment of differential nerve block during lumbar epidural anesthesia].

The study was performed to evaluate differential neural blockade during lumbar epidural anesthesia with a cutaneous current perception threshold (CPT) sensory testing device. Fourteen patients undergoing elective gynecological surgery received 10 ml of 2% lidocaine through an epidural catheter inserted at the L 1/2 interspace. CPTs at 2000, 250, and 5 Hz stimulation and sensation to light touch, temperature, and pinprick at ipsilateral dermatomes V, Th 9, and L 2 were measured before and every 5 min, until 60 min after the epidural lidocaine. The epidural block caused a significant increase in all CPTs at dermatome L 2 and in CPTs at 250 and 5 Hz at Th 9. Touch sensation at Th 9 was intact during the study period in 12 patients, most of whom lost sensation to the other stimulus: 12 patients did not respond to the cold stimulus and 10 patients to the pinprick. At L 2, sensory block to light touch, temperature, and pinprick was found in 11, 14, and 14 patients, respectively. There was no effect on any measurements made at V. In conclusion, epidural lidocaine results in a differential neural blockade as measured with CPT testing. Since the 2000-Hz stimulus detect abnormalities that correlate with large fiber functioning, it is suggested that loss of touch sensation is associated with effects of epidural lidocaine on large fibers.

Adult↗
PubMed1998

The advantages of the lateral decubitus position after spinal anesthesia with hyperbaric tetracaine.

UNLABELLED: We investigated the effects of lateral decubitus positioning after spinal anesthesia with hyperbaric tetracaine on the spread of sensory blockade and hemodynamic variables. One hundred ASA physical status I or II patients scheduled for elective surgery to the lower limb received spinal anesthesia at a rate of approximately 0.1 mL/s using 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine in the lateral decubitus position with the operated side dependent. They were randomly divided into three groups: patients in Group I were placed supine immediately after spinal injection; those in Group II remained in the lateral position for 10 min before being turned supine; those in Group III were kept in the lateral position for 20 min then turned supine. Neural block was assessed by cold, pinprick, and touch sensation, and a modified Bromage scale. Hemodynamic variables included blood pressure, heart rate, and the use of ephedrine for the treatment of hypotension. The median (10th, 90th percentiles) peak dermatomal level to pinprick on the dependent side in Group III was T8 (T11, T5), which was significantly lower than that in Groups I and II, which extended to T4 (T9, T3) and T5 (T10, T2), respectively (P < 0.05). The difference in the maximal cephalad spread of sensory blockade between both sides in Group III was only one dermatome but was statistically significant (P < 0.05); in contrast, there was no significant difference in the maximal sensory level between both sides in Groups I and II. The use of ephedrine for the treatment of hypotension was significantly less frequent in Group III than the other groups. We conclude that keeping a patient in the lateral decubitus position for 20 min after hyperbaric tetracaine spinal anesthesia maintains preferential anesthetic distribution to the dependent side. Despite small differences between the two sides, the restricted spread of blockade and less hemodynamic variability may be clinically advantageous. IMPLICATIONS: The effects of posture on the spread of hyperbaric spinal anesthesia have not been adequately investigated. The results of the present study suggest an advantage of prolonged lateral decubitus positioning after intrathecal hyperbaric tetracaine.

Adolescent↗
PubMed1998

Characteristics of tolerance to somatic and visceral antinociception after continuous epidural infusion of morphine in rats.

UNLABELLED: A continuous epidural infusion of morphine may cause a complicated tolerance to develop, depending on the spinal and supraspinal sites. We designed this study to clarify the characteristics of the tolerance to somatic and visceral antinociception after epidural morphine infusion. Rats received epidural infusion of morphine at the rates of 50 or 100 microg kg(-1) h(-1), or isotonic sodium chloride solution for 7 days. The tail-flick (TF) test and colorectal distension (CD) test were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests were performed on Days 1, 2, 3, 4, and 7. After 7 days, time-response curves after epidural morphine (10 microg) or intraperitoneal morphine (3 mg) challenge tests were conducted to assess the magnitude of tolerance. Epidurally infused morphine significantly increased percent maximal possible effects (%MPEs) (P < 0.05) in both the TF and CD tests, depending on the concentration of morphine. In the epidural morphine challenge test, increases in %MPEs were significantly attenuated (P < 0.05) in the morphine-infused group compared with the isotonic sodium chloride solution-infused group. The increases in %MPEs in the intraperitoneal challenge test were also attenuated in the morphine-infused group. We conclude that morphine tolerance to both somatic and visceral antinociception develops rapidly during epidural infusion and is based on the development of tolerance at the systemic, as well as the epidural, level. IMPLICATIONS: A continuous epidural infusion of morphine rapidly induces tolerance to visceral and somatic antinociception in rats. This development is based on the development of tolerance at the systemic, as well as the epidural, level.

Analgesics, Opioid↗
PubMed1997

The addition of phenylephrine contributes to the development of transient neurologic symptoms after spinal anesthesia with 0.5% tetracaine.

BACKGROUND: Recent reports indicate that transient neurologic symptoms commonly occur after single-injection spinal anesthesia with lidocaine. Information regarding tetracaine has been limited to a single case report. In addition, little is known about the cause of these symptoms or the cofactors that affect their occurrence. The present study sought to determine whether the presence of phenylephrine or the concentration of glucose in the anesthetic solution affects the incidence of transient neurologic symptoms after spinal anesthesia with 0.5% tetracaine. METHODS: One-hundred sixty patients classified as American Society of Anesthesiologists physical status I or II who were scheduled for elective surgery on a lower limb or perineum were sequentially assigned to one of four equal groups to receive intrathecal 0.5% tetracaine in 7.5% or 0.75% glucose, with or without 0.125% phenylephrine. Patients were evaluated on postoperative day one for the presence of pain, dysesthesia, or both in the legs or buttocks by an investigator unaware of the drug given. RESULTS: Symptoms were present in 10 patients (12.5%) receiving a spinal anesthetic containing phenylephrine, but in only one patient (1.3%) receiving spinal anesthesia without phenylephrine. There was no significant difference in the incidence of symptoms between groups receiving 7.5% glucose and those receiving 0.75% glucose (8.8% and 5% of patients, respectively). CONCLUSIONS: These results suggest that adding phenylephrine to tetracaine for spinal anesthesia increases the potential for transient neurologic symptoms, but that the concentration of glucose does not affect their occurrence.

Adult↗
PubMed1997

[Anesthetic management using transesophageal echocardiography during removal of a cardiac myxoma].

Removal of a cardiac myxoma can be complicated by mitral stenosis, arterial embolism and so on, all of which may be life-threatening but difficult to diagnose. We describe the use of transesophageal echocardiography (TEE) for the anesthetic management of two patients undergoing removal of a large myxoma in the left atrium (LA). The first case is a 78-yr-old woman, who was suffering from cardiac cachexy with a large LA myxoma. The anesthetic management of her surgery required the prevention of a decrease in cardiac output caused by anesthetic agents, massive bleeding and surgical procedures. The second case is an asymptomatic 60-yr-old man with LA myxoma, which appeared adherent to the mitral orifice in diastole. The goal of the anesthetic management of him was to prevent the obstruction of transmitral blood flow caused by the decrease in preload on the heart. Throughout the surgeries, TEE monitoring was conducted and helped decide the doses and/or rate of inotropes and vasodilators as well as the transfusion of fluid and blood to obtain stable circulatory conditions. It was also found to be of considerable value in understanding the pathophysiology of the tumors in LA. In conclusion, TEE monitoring during the surgery can be of much use both in the diagnosis and the anesthetic management of a patient with a large LA myxoma.

Aged↗
PubMed1996

Comparison of glucose 7.5% and 0.75% with or without phenylephrine for tetracaine spinal anaesthesia.

PURPOSE: To investigate whether a marginally hyperbaric tetracaine solution with or without phenylephrine could produce consistent blocks as compared with a conventionally hyperbaric tetracaine solution injected at L3-4 interspace with the patient in the lateral position. METHODS: We studied 120 ASA I or II patients scheduled for elective surgery to the lower limb. Patients were randomly divided into four equal groups to receive spinal anaesthesia using tetracaine 0.5% in glucose 0.75% or 7.5%, with or without phenylephrine 0.125%. Neural block was assessed in a double-blind manner by cold, pinprick, and touch sensation, and a modified Bromage scale after the injection of the study drug. RESULTS: The median (10th, 90th percentiles) peak dermatomal level to pinprick obtained by the solutions in glucose 0.75% was T10 (L1, T5), which was lower than that obtained by the solution in glucose 7.5% extending to T5 (T10, T3) and T5 (T10, T2) with or without phenylephrine, respectively (P < 0.0001). The addition of phenylephrine prolonged the time to two-segment regression but did not change the maximum extent of blocks. CONCLUSIONS: A marginally hyperbaric tetracaine with or without phenylephrine produced consistent blocks with spread restricted to the lower thoracic segments when administered intrathecally at the L3-4 interspace with the patient in the lateral position.

Adult↗
PubMed1996

Antinociceptive effects of ONO-9902, an enkephalinase inhibitor, after visceral stress condition in rats.

PURPOSE: The present study was designed to examine the antinociceptive effects of orally administered ONO-9902, an enkephalinase inhibitor, on both somatic and visceral pain after visceral stress conditions. METHODS: Twenty six male rats were examined. Tail-flick (TF) and colorectal distension (CD) tests were used to determine somatic and visceral antinociceptive effects, respectively. Measurements were performed in rats under immediate post-stress conditions (group ST; n = 14) and in rats nor under stress conditions (group NST; n = 12). In the stressed group, the same device, CD, for visceral antinociceptive effects was used for visceral stress and was applied with an intracolonic pressure of 60 mmHg for 20 min after drug administration. The TF latency and CD threshold were measured before and at 30, 40, 50, 60 and 90 min after administration of ONO-9902 300 mg.kg-1 or distilled water. RESULTS: Orally administered ONO-9902 did not produce any changes in the % maximum possible effect (%MPE) in either TF or CD tests in the unstressed group. In the stressed group, %MPE in the CD test increased 18% and 31% at 30 and 40 min, respectively, after oral administration of ONO-9902 compared with the control group (P < 0.05). However, %MPE to TF test did not alter even after the CD-induced stress condition. CONCLUSION: These results suggest that ONO-9902 may have analgesic effects on visceral pain but not on somatic pain under immediate post-stress conditions.

Analgesics, Non-Narcotic↗
PubMed1996

Transient radicular pain following spinal anesthesia: review of the literature and report of a case involving 2% lidocaine.

Recent reports of transient radicular irritation following intrathecal administration of 5% lidocaine in 7.5% dextrose, a common drug choice in many obstetric centers, have generated concern that its use for single injection spinal anesthesia can result in transient neurologic toxicity. Accordingly, many have advocated dilution of this anesthetic solution prior to subarachnoid administration. The present report describes a case in which transient neurologic symptoms occurred following intrathecal injection of a solution containing approximately 2% lidocaine. The similarity of the present case to those previously reported implies a common etiology and suggests that risk is not restricted to the use of 5% lidocaine with 7.5% glucose. It underscores the need for carefully controlled prospective evaluation of the factors that affect transient neurologic dysfunction following spinal anesthesia.

Journal Article↗
PubMed1996

The effects of epidural anesthesia on ventilatory response to hypercapnia and hypoxia in elderly patients.

Epidural anesthesia may impair pulmonary ventilation in elderly people. We examined the effects of lumbar or thoracic epidural anesthesia on resting ventilation, arterial blood gas tensions, the ventilatory response to hypercapnia, and progressive isocapnic hypoxia in elderly patients. Two groups of eight unpremedicated elderly patients, aged 65 yr or older, undergoing lower or upper abdominal surgery, respectively, were studied twice before and 20 min after the lumbar or thoracic administration of 10 mL of 2% lidocaine. Lumbar epidural anesthesia had no significant effect on resting ventilation, whereas thoracic epidural caused a significant 13% decrease in minute ventilation and a 14% decrease in tidal volume (P < 0.05). The ventilatory response to hypercapnia was significantly increased after lumbar epidural anesthesia, but no change was observed after thoracic epidural anesthesia. The slope of the hypoxic response curve did not show any change in either group, but minute ventilation at a Spo2 of 90% significantly increased after lumbar epidural anesthesia (P < 0.05). We conclude that neither lumbar nor thoracic epidural anesthesia per se impairs the ventilatory response to hypercapnia and hypoxia, despite slight impairment in resting ventilation by thoracic epidural anesthesia, in elderly patients.

Aged↗
PubMed1996

Intrathecal catheterization in the rat. Improved technique for morphologic analysis of drug-induced injury.

BACKGROUND: The authors previously described an in vivo model suitable for investigation of functional impairment induced by intrathecally injected local anesthetic. However, meaningful histologic analysis could not be performed because catheterization, per se, induced morphologic changes in control animals. In the current experiments, the authors sought to identify an alternative, less reactive, catheterization technique for intrathecal drug administration. METHODS: Twenty-five rats received an intrathecal infusion of normal saline through a catheter composed of either 28-gauge polyurethane, 32-gauge polyimide, 32-gauge polyurethane, PE-10 polyethylene, or PE-10 polyethylene that had been stretched to twice its original length. Seven days after infusion, sensory function was assessed using the tail-flick test, and the spinal cord and nerve roots were prepared for neuropathologic evaluation. RESULTS: There was no significant difference in sensory function among groups. Animals in which 28-gauge polyurethane, 32-gauge polyimide, PE-10, and double-stretched PE-10 had been implanted had moderate to severe nerve injury in 11%, 14%, 23%, and 8% of fascicles, respectively, whereas none of the animals in which 32-gauge polyurethane was implanted had any evidence of moderate or severe damage. CONCLUSIONS: Morphologic changes induced by intrathecal catheterization in the rat can be minimized by the use of 32-gauge polyurethane tubing.

Animals↗