PubMed Health⌕ Search

Biomedical subjects

Tomoki Nishiyama

Publications and source records attributed to Tomoki Nishiyama.

At least 55 records · Page 3Linked to original sources
PubMed2004

[Cardiac arrest during bilateral inguinal herniorrhaphy under epidural anesthesia].

A 73-year-old man with hyper gamma-globulinemia was scheduled for bilateral herniorrhaphy and hemorroidectomy. In preoperative examination, the serum concentrations of gamma-globulin and total protein were 7.31 g x dl(-1) and 11.9 g x dl(-1). Although platelet count was 6.5 x 10(4) x microl(-1), epidural anesthesia was selected to minimize hemodynamic changes which could increase a risk of thrombosis. Epidural catheters were inserted at T 12-L 1 and L 4-5. Analgesia level checked by a pin prick was T 4 after administering 10 ml of 2% lidocaine, 7 ml into T 12-L 1 and 3 ml into L 4-5. Bilateral herniorrhaphy started simultaneously. When bilateral peritoneum was stretched, heart rate suddenly decreased to 40 beats x min(-1). Although 0.5 mg of atropine was immediately administered intravenously, cardiac arrest was observed for several seconds and the patient was unconscious for about 10 seconds. After stopping surgery, heart beat and consciousness recovered immediately. By administration of 10 mg of ephedrine, blood pressure increased to 130/80 mmHg with heart rate of 55 beats x min(-1). Vagal reflex induced by bilateral inguinal herniorrhaphy might cause cardiac arrest. We should be careful for vagal reflex during bilateral herniorrhaphy.

Aged↗
PubMed2003

Spinally mediated analgesia and receptor binding affinity of epibatidine analogs.

Two epibatidine derivatives, (1R, 2R, 5S)-A-(2-chloropyridinyl) azabicyclo [3.2.1] octane; A=2 beta: analog 1, 2 alpha: analog 2, were investigated for their spinally mediated analgesic effects and binding affinity to nicotinic acetylcholine receptors. The tail flick response and behavioral side effects were studied after intrathecal agents in rats. The membrane preparations of the Torpedo Californica and rat cerebral cortices were used for radioligand binding utilizing [3H] epibatidine displacement. Their affinity to muscular and neuronal nicotinic acetylcholine receptors and spinally mediated analgesic potencies were 15, 20, and 3.8 times (analog 1) and 2000, 30,000, and 3.3 times (analog 2) less than epibatidine, respectively. Two times the analgesic 50% effective doses (ED(50)s) of the analogs did not induce side effects, while one-third of that of epibatidine induced motor disturbance. In summary, the two epibatidine analogs have higher potency ratio of spinally mediated analgesia/side effects than epibatidine.

Analgesia↗
PubMed2003

Comparison of hemodynamic and anesthetic effects of hyperbaric bupivacaine and tetracaine in spinal anesthesia.

PURPOSE: To compare the anesthetic and hemodynamic effects and the predictive factor of anesthesia level of commonly used preparations of hyperbaric bupivacaine and tetracaine in spinal anesthesia. METHODS: Two hundred patients aged 40 to 75 years with ASA physical status I or II were anesthetized spinally via the L4-5 interspace using 0.5% hyperbaric bupivacaine in 7.27% glucose (Bupivacaine group, n = 100) or 0.5% hyperbaric tetracaine dissolved in a 10% glucose solution (Tetracaine group, n = 100) in a lateral position. The volume of anesthetic used was decided by the resident according to the surgical procedure. Patients were returned to the supine position immediately after drug injection. Blood pressure, heart rate, and anesthesia level tested by cold sensation were measured for 30 min. RESULTS: Blood pressure and heart rate decreased significantly but without any differences between the groups. The volume of drug used was significantly larger in the Bupivacaine group (2.6 +/- 0.5 ml) than in the Tetracaine group (2.1 +/- 0.4 ml) to obtain the same maximum anesthesia level. The time to reach the maximum anesthesia level was significantly longer in the Bupivacaine group (18 +/- 7 min) than in the Tetracaine group (15 +/- 6 min). The volume of the drug was the only predictive factor of the maximum anesthesia level in both groups: Level (as expressed by the number of anesthetized segments from S5 to cephalad) = 1.55 x (volume in ml) + 13.06 in the Bupivacaine group, and 2.59 x (volume) + 11.46 in the Tetracaine group. CONCLUSION: In spinal anesthesia, hyperbaric tetracaine in 10% glucose induced a faster and higher spread of anesthesia than hyperbaric bupivacaine in 7.27% glucose without any differences in hemodynamics.

Adult↗
PubMed2003

Serum and cerebrospinal fluid concentrations of midazolam after epidural administration in dogs.

UNLABELLED: The epidural administration of midazolam has analgesic effects that might be mediated by gamma-aminobutyric acid type A receptors in the spinal cord. In this study, we examined both serum and cerebrospinal fluid (CSF) concentrations of midazolam after epidural administration to investigate the possibility of midazolam entering CSF directly from the epidural space. Five male mongrel dogs had catheters inserted in a femoral artery, the epidural space at L3-4, and the intrathecal space at the atlanto-occipital region under general anesthesia. Midazolam 1 mg/kg was epidurally administered, and arterial blood and CSF samples were collected until 240 min after the midazolam administration to measure midazolam concentration. Serum midazolam concentration increased and reached a peak at 30 min after the administration (224.8 +/- 30.5 ng/mL) and then decreased to 25.8 +/- 6.0 ng/mL at 240 min. Midazolam concentration in the CSF was less than the detection limit at 5 min, reached a peak at 30 min after the administration (7.2 +/- 4.7 ng/mL), and decreased to 3.6 +/- 3.3 ng/mL at 240 min. In conclusion, epidurally administered midazolam enters CSF, but CSF concentrations are only 3% of those in the systemic circulation. IMPLICATIONS: Midazolam, which has spinally mediated analgesic potency, was epidurally administered in dogs, and serum and cerebrospinal fluid concentrations were measured. Epidurally administered midazolam enters the cerebrospinal fluid, but concentrations are only 3% of those in the systemic circulation.

Animals↗
PubMed2003

Midazolam can potentiate the analgesic effects of intrathecal bupivacaine on thermal- or inflammatory-induced pain.

UNLABELLED: Epidurally administered midazolam can potentiate analgesia by epidural bupivacaine. However, whether this effect is synergistic or additive is not known. In this study, we investigated the spinally-mediated analgesic interaction between midazolam and bupivacaine by using the tail-flick and formalin tests in rats with chronically implanted catheters. Behavioral effects were also observed. The dose dependency of analgesia and the 50% effective doses of intrathecal midazolam and bupivacaine were determined, and then the interaction of these two drugs was examined with an isobolographic analysis. Both drugs had dose-dependent analgesic effects in both the tail-flick test and the formalin test. The 50% effective dose values of the combination were significantly lower than the calculated additive values in both tests (P = 0.023 in the tail-flick test; P = 0.0025 in Phase 1 and 0.047 in Phase 2 of the formalin test). Behavioral side effects decreased in the combination group compared with each drug alone. In conclusion, intrathecally administered midazolam and bupivacaine had synergistic analgesic effects on acute thermal- or inflammatory-induced pain, with decreased behavioral side effects. IMPLICATIONS: In both acute thermal- and inflammatory-induced pain, intrathecally administered midazolam and bupivacaine produced synergistic analgesia with decreased side effects in intrathecally catheterized rats.

Anesthetics, Intravenous↗
PubMed2003

Core temperature monitoring with new ventilatory devices.

UNLABELLED: Widespread use of new airway devices, such as the laryngeal mask airway (LMA) and the cuffed oropharyngeal airway (COPA), preclude measuring core temperature in the distal esophagus. Therefore, we tested the hypothesis that core temperature measured with a thermocouple positioned on a LMA or COPA is sufficiently accurate and precise for clinical use. Temperatures were recorded from thermocouples positioned on the cuffs of LMAs or COPAs in 36 patients scheduled for prolonged orthopedic surgery or therapeutic hyperthermia for cancer. These temperatures, recorded at 15-min intervals, were compared with simultaneously obtained nasopharynx and tympanic membrane temperatures. Data were compared by linear regression and the bias calculated. Temperatures measured on the LMA correlated well with both nasopharyngeal (r(2) = 0.94) and tympanic membrane (r(2) = 0.94) temperatures. Temperatures measured on the COPA also correlated well with those on the nasopharynx (r(2) = 0.97) and tympanic membrane (r(2) = 0.96). The fraction of temperatures that differed from nasopharynx temperature by more than +/-0.5 degrees C was 8% with LMA and 11% with COPA; the fraction of temperatures that differed from tympanic temperature by more than +/-0.5 degrees C was 7% with LMA and 10% with COPA. These results suggest that body temperature measured from the cuffs of COPA or LMAs is sufficiently accurate for routine clinical use. IMPLICATIONS: Temperatures measured on airway devices correlated well with independent measurements of core body temperature. Thus, body temperature measured on the cuffs of airway devices is sufficiently accurate for routine use.

Adult↗
PubMed2003

Doxapram produces a dose-dependent reduction in the shivering threshold in rabbits.

Dopamine is a thermoregulatory neurotransmitter that provokes hypothermia when injected in or near the hypothalamus. Doxapram stimulates release of dopamine from carotid bodies, but is known to have central effects that are probably, at least in part, similarly mediated. We thus tested the hypothesis that doxapram produces a substantial, dose-dependent reduction in the shivering threshold in rabbits. Twenty-four rabbits, anesthetized with isoflurane, were randomly assigned to 1) saline (control), 2) 0.25 mg x kg(-1) x h(-1) doxapram, or 3) 0.50 mg x kg(-1) x h(-1) doxapram. These doses are within the recommended range for humans. Body temperature was reduced at a rate of 2 degrees to 3 degrees C/h by perfusing water at 10 degrees C through a U-shaped thermode positioned in the colon. Core temperatures were recorded from the distal esophagus. A blinded observer evaluated shivering. Core temperature at the onset of shivering defined the threshold. Data were analyzed with a one-way analysis of variance; P < 0.05 was considered statistically significant. Hemodynamic and respiratory responses were comparable in the groups. The control rabbits shivered at 36.3 degrees +/- 0.3 degrees C, those given 0.25 mg x kg(-1) x h(-1) doxapram shivered at 34.8 degrees +/- 0.5 degrees C, and those given 0.50 mg x kg(-1) x h(-1) shivered at 33.7 degrees +/- 0.6 degrees C. All the shivering thresholds significantly (P < 0.001) differed from one another. The magnitude of this inhibition, if similar in humans, would be clinically important.

Anesthesia, Inhalation↗
PubMed2003

[Bronchospasm during upper gastrointestinal endoscopy under sedation].

We experienced a case of bronchospasm during upper gastrointestinal endoscopy under sedation. An 80-year-old man came to our hospital with abdominal distension with pain, nausea and vomiting. He has the history of splenectomy, cholecystectomy for hemolytic anemia and thyroidectomy for thyroid cancer, surgery for bilateral shoulder joints and diabetes. Abdominal X-ray suggested obstruction of the small intestine. On the third hospital day, gastrointestinal endoscopy was scheduled for insertion of a long ileus tube. Under sedation with diazepam 10 mg and local anesthesia of the pharynx with lidocaine spray 24 mg, the endoscope was inserted and when it reached the esophageal-gastrojunction, respiratory rate increased to 30 breaths.min-1 with expiratory stridor. The endoscope was removed immediately. He was oro-tracheally intubated and artificially ventilated. On the fourth hospital day, he was extubated under bronchoscopy. No abnormalities were observed in the trachea, vocal cord, pharynx and larynx. Later, it was revealed that he had a history of hoarseness and dysphasia. His left recurrent nerve and cervical nerve had been resected with thyroid and right cervical nerve anastomosed to the rest of the left recurrent nerve. The insertion of upper gastrointestinal endoscope might have induced bronchospasm stimulating distal esophageal afferent vagal reflex partly by regurgitation of gastric acid under sedation.

Aged↗
PubMed2003

[A new heat and moisture exchanger, Trach-Vent Plus, for patients with spontaneous respiration].

A new heat and moisture exchanger, Trach-Vent Plus is now available in Japan. A heat and moisture exchanger, Trach-Vent and oxygen-supplying tool, Oxy-Vent are made in one unit as a Trach-Vent Plus. This is smaller and lighter than the combination of Trach-Vent and Oxy-Vent. Oxygen supplying tube can be connected to the side of the filter. There is a silicon membrane with slits in the center of the tool, to which patients's airway opens directly. The membrane prevents patients from dust, but suction of sputa is easy through the slits. This new heat and moisture exchanger, Trach-Vent Plus is useful to administer oxygen to intubated patients breathing spontaneously, especially with tracheostomy.

Hot Temperature↗
PubMed2003

[Usefulness of a new nasal cannula with an end-tidal carbon dioxide measuring port].

BACKGROUND: During light sedation under local anesthesia, usually only percutaneous arterial oxygen saturation (SpO2) has been monitored for respiration. Measuring end-tidal carbon dioxide tension (EtCO2) has been difficult in such cases because of many air leaks from mask or cannula. We investigated the usefulness of a new nasal cannula with which EtCO2 can be monitored simultaneously with oxygen delivery. METHODS: Forty patients receiving epidural and spinal anesthesia were sedated with intravenous midazolam followed by propofol infusion. Oxygen 2l.min-1 was administered by a new nasal cannula of which one side of the face piece provides oxygen and the other side of it is an EtCO2 measuring port. SpO2 and EtCO2 were measured. RESULTS: The lowest SpO2 was 96 +/- 2%. The EtCO2 wave and value were demonstrated all the time during surgery in 24 patients, while in the other 16 patients sometimes it failed to indicate wave and value of EtCO2 when patients were snoring or moved their face. CONCLUSION: A new cannula with EtCO2 port is useful to oxygenate and measure EtCO2 simultaneously except when patients snore or move.

Adult↗
PubMed2003

[A questionnaire study about perioperative blood transfusion].

BACKGROUND: Red blood cell concentrates in mannitol-adenine-phosphate, autologous blood transfusion, type & screen (T & S), maximum surgical blood order schedule (MSBOS), and a new guideline have been introduced in blood transfusion. To know the present state of perioperative blood transfusion, we did a questionnaire study. METHODS: A questionnaire was sent to anesthesia departments of 1,600 hospitals. RESULTS: Six hundred and fifty hospitals (40.6%) returned the answers. Informed consent is obtained for blood transfusion in every case in 89.8%. Blood loss volume is the most popular indicator to start blood transfusion. Hemoglobin 8 g.dl-1 and hematocrit 25% are also the indicators to start blood transfusion. As an autologous blood transfusion, predeposited (PAT) is the most commonly used. Even when expected blood loss is 3,000 ml, more than 80% of the respondents do not prepare whole blood. Radiation of blood preparation before transfusion is performed in 89.8%. Only half of the hospitals carry out T & S and/or MSBOS. A new guideline is thought to be inadequate in more than 20%. CONCLUSIONS: A questionnaire study indicates that autologous blood transfusion, radiation, leukocyte depletion, T & S, and MSBOS are introduced in our practice. Whole blood is not used, but a new guideline seems to be inadequate.

Anesthesiology↗
PubMed2003

[A case report of the laryngeal edema and peripheral cyanosis after extubation of the tracheal tube].

A 65-year-old male in malnutrition due to advanced colon cancer underwent resection of transverse colon tumor and the invaded abdominal muscles with necrosis and abscess. After epidural catheter insertion between Th 10-11 for 9 cm cephalad, anesthesia was induced with thiopental 200 mg and fentanyl 50 micrograms. Tracheal intubation was done with vecuronium 5 mg, and anesthesia was maintained with sevoflurane with nitrous oxide in oxygen and epidural block. During surgery, systolic blood pressure often went up to 130 to 140 mmHg and down to 50 to 60 mmHg. Dopamine 3-5 micrograms.kg-1.min-1 was administered but occasional ephedrine bolus injection was still necessary. The intestine, including the intact part, was edematous. After the surgery, when systolic blood pressure was stable at about 130 mmHg and his consciousness was clear with regular spontaneous respiration, the tracheal tube was removed. However, soon after the extubation, expiratory stridor and cyanosis of the bilateral hands and feet were observed. Hydrocortisone 200 mg and nicardipine 0.5 mg were administered and room temperature was raised. About 30 minutes later, stridor and cyanosis subsided. In the ward after surgery, only hoarseness was observed. The stridor might have been due to the laryngeal edema, which could be attributed to stimulation by tracheal tube in the patient with malnutrition. The hemodynamic instability during surgery and cyanosis after extubation might have come from changes of the vascular resistance by sepsis.

Aged↗
PubMed2003

[Sedation with intravenous midazolam during upper gastrointestinal endoscopy--changes in hemodynamics, oxygen saturation and memory].

BACKGROUND: Cardiorespiratory adverse effects are often observed in patients undergoing upper gastrointestinal endoscopy with sedation. In this study, we examined hemodynamics, oxygen saturation and memory during upper gastrointestinal endoscopy under sedation with intravenous midazolam. METHODS: Eight healthy outpatients without any obvious complications received intravenous midazolam 5 mg for sedation for upper gastrointestinal endoscopy. Blood pressure, heart rate and percutaneous arterial oxygen saturation (SpO2) were measured before, during and after endoscopy. After the arousal by intravenous flumazenil, we inquired the patients about the level of memory during the endoscopy. RESULTS: Blood pressure decreased significantly two minutes after midazolam administration, but increased significantly after the insertion of an endoscope which was not different from the control value. Heart rate increased significantly one and three minutes after the insertion of the endoscope. SpO2 decreased significantly after midazolam administration and stayed at around 95%. No patients remembered the procedure. CONCLUSIONS: Sedation with intravenous midazolam during upper gastrointestinal endoscopy is useful to control the cardiovascular responses, and to obtain amnesia. However, a decrease in SpO2 should be watched carefully.

Adult↗
PubMed2002

Effects of adding midazolam on the postoperative epidural analgesia with two different doses of bupivacaine.

STUDY OBJECTIVE: To investigate the interaction of midazolam with different doses of bupivacaine, by comparing the analgesic, sedative, and amnesic effects of continuous epidural midazolam with two different doses of bupivacaine. DESIGN: Prospective, randomized study. SETTING: Operating room and intensive care units of a university hospital. PATIENTS: 100 ASA physical status I and II postgastrectomy patients (40-70 yrs) without any complications. INTERVENTIONS: Patients were divided into four groups (n = 25) and administered continuous thoracic epidural infusion (40 mL/12 hr) of the drugs via a balloon infuser. The contents of the infuser (40 mL) were bupivacaine 180 mg with midazolam 20 mg (HM group), 90 mg with midazolam 20 mg (LM group), 180 mg without midazolam (HC group), or 90 mg without midazolam (LC group). As a rescue medication, 50 mg indomethacin suppository was the first choice, then IM pentazocine 15 mg. MEASUREMENTS: Analgesia and sedation scores, blood pressure (BP), heart rate, respiratory rate, oxygen saturation, amnesia, the number of rescue medications, and time to the first rescue medication were monitored. The area under the curves (AUCs) of analgesia and sedation scores, and BP were calculated. MAIN RESULTS: In the HM group, significantly better analgesia and sedation were obtained and the number of rescue medications given was the lowest of the four groups. The time to the first rescue medication was longest in the HM group, followed by the LM group, then the HC, and, finally, LC groups. The numbers of the patients with amnesia were greater in the HM and LM groups than the HC and LC groups. Blood pressure decreased significantly in the HM group but no treatment was necessary. The AUCs of analgesia and sedation scores, and BP were lowest in the HM group. CONCLUSIONS: Adding midazolam increased not only analgesic but also sedative effect with increasing dose of bupivacaine in a postoperative continuous epidural administration.

Adjuvants, Anesthesia↗
PubMed2002

Rapid inhalation induction with 7% sevoflurane combined with intravenous midazolam.

STUDY OBJECTIVE: To identify an improved rapid inhalation induction (RII) technique by investigating hemodynamics and heart rate variability of induction with midazolam and RII with 7% sevoflurane in comparison with RII alone. DESIGN: Prospective, randomized study. SETTING: Operating room of a university hospitals. PATIENTS: 40 patients scheduled for gastrectomy without complications. INTERVENTIONS: In the sevoflurane (Sev) group, anesthesia was induced with tidal volume breathing of 7% sevoflurane with 50% nitrous oxide (N(2)O) in oxygen (O(2)) for 3 minutes. In the midazolam-sevoflurane group (Mid-Sev) intravenous midazolam 0.1 mg/kg was given, followed by 7% sevoflurane with 50% N(2)O. In both groups, endotracheal intubation was facilitated with vecuronium 0.15 mg/kg, which was administered at loss of consciousness. MEASUREMENTS: Blood pressure, heart rate, heart rate variability, time to loss of response to verbal command (sleep time), rate of body movement or cough during induction, and patient satisfaction were monitored. MAIN RESULTS: Blood pressure and heart rate increased significantly in the Sev group but not in the Mid-Sev group. Heart rate was significantly higher in the Sev group at 1 minute after intubation. High-frequency component (cardiac parasympathetic activity) in heart rate variability increased before intubation, with a higher value seen in the Sev group than the Mid-Sev group. The ratio of low-frequency component to high-frequency component (cardiac sympathetic activity) did not change in either group. Sleep time did not differ between the two groups. The numbers of patients with body movement and cough, and patients who were not satisfied with the induction method were, respectively, four, three, and eight in the Sev group; and one, zero, and two in the Mid-Sev group. The last value was significantly higher in the Sev group (p = 0.0285). CONCLUSIONS: The addition of intravenous midazolam 0.1 mg/kg provides more stable hemodynamics, cardiac autonomic nervous system activity, and patient satisfaction in RII with 7% sevoflurane.

Adult↗
PubMed2002

Effects of combining midazolam and barbiturate on the response to tracheal intubation: changes in autonomic nervous system.

STUDY OBJECTIVE: To investigate the effects on the autonomic nervous system of anesthesia induction with a combination of midazolam and barbiturate using plasma catecholamine concentration and heart rate (HR) variability in comparison with the induction with barbiturate alone. DESIGN: Prospective study. SETTING: Operating room of a university hospital. PATIENTS: 40 ASA physical status I and II patients aged 30 to 70 years, who were scheduled for general anesthesia. INTERVENTIONS: Anesthesia was induced with 0.1 mg/kg midazolam followed by 3 mg/kg thiopental sodium (Midazolam-Barbiturate group) or thiopental 5 mg/kg (Barbiturate group) with 6 L/min oxygen. MEASUREMENTS: Arterial blood pressure (BP), HR, HR variability, and plasma concentrations of epinephrine and norepinephrine were measured. MAIN RESULTS: Blood pressure and HR increased in response to tracheal intubation in both groups, but the increase was significantly larger in the Barbiturate group. In the Barbiturate group, the high-frequency component (HF) in HR variability increased significantly during intubation, whereas in the Midazolam-Barbiturate group, HF decreased continuously. The low-frequency component (LF)/HF ratio increased in both groups, with significantly higher values noted in the Barbiturate group. Plasma epinephrine concentrations decreased before intubation and increased in response to tracheal intubation in the Barbiturate group. Finally, plasma norepinephrine concentrations increased in response to tracheal intubation only in the Barbiturate group. CONCLUSIONS: Anesthesia induction with a combination of midazolam-thiopental was effective in reducing hemodynamic and cardiac autonomic nervous system responses to tracheal intubation in comparison with the conventional induction with thiopental alone.

Adult↗