Search PubMed⌕ Search

Biomedical subjects

A Matsuki

Publications and source records attributed to A Matsuki.

At least 37 records · Page 2Linked to original sources
PubMed2001

Allelic loss mapping and physical delineation of a region harboring a thymic lymphoma suppressor gene on mouse chromosome 16.

Our previous mapping of allelic loss in gamma-ray induced thymic lymphomas in F(1) hybrid and backcross mice between BALB/c and MSM strains identified three regions with high frequencies of allelic loss which probably harbor a tumor suppressor gene. One region, Tlsr7, exists near the D16 Mit122 locus on chromosome 16. This study has further localized Tlsr7 by constructing a physical map and scanning a total of 587 thymic lymphomas. The map consists of 13 overlapping BAC clones and isolation of BAC-derived polymorphic probes leads to fine mapping of allelic losses. Eleven lymphomas show informative breakpoints of allelic loss regions relative to the flanking markers on the map. Pulsed-field gel electrophoresis of NotI digests of the clones shows that the commonly lost region is localized within an approximately 300 kb interval near D16Mit192. This map is invaluable to facilitate the identification of genes in the Tlsr7 region.

Alleles↗
PubMed2001

Increased noradrenaline release from rat preoptic area during and after sevoflurane and isoflurane anesthesia.

PURPOSE: To study the effects of sevoflurane and isoflurane on noradrenaline release from the rat preoptic area (POA). METHOD: Sixteen male Wistar rats were studied. A microdialysis probe with a 2 mm long semipermeable membrane was implanted in the POA. Dialysates were collected at intervals often minutes. After obtaining five control samples for 50 min, 30 min inhalation of 3% sevoflurane or 1.8% isoflurane was performed. After cessation of the inhalation, five more samples were obtained for 50 min as recovery phase. Noradrenaline (NA) concentration in the dialysates was measured by high pressure liquid chromatography with an electrochemical detector. RESULTS: Both sevoflurane and isoflurane caused marked increases in NA release from the rat POA (sevoflurane 233% at 20 min, isoflurane 357% at ten minutes after the start of inhalation). The marked NA releases were also observed during the emergence from sevoflurane and isoflurane anesthesia (sevoflurane 269% at 20 min, isoflurane 368% at ten minutes in the recovery phase). CONCLUSION: This study suggests that enhanced release of NA in the POA during sevoflurane and isoflurane may explain the excitatory phase observed during the peri-anesthetic period with these agents.

Anesthesia↗
PubMed2001

Ketamine and midazolam kinetics during continuous hemodiafiltration in patients with multiple organ dysfunction syndrome.

OBJECTIVE: To assess the effect of continuous hemodiafiltration (CHDF) on ketamine and midazolam kinetics in multiple organ dysfunction syndrome (MODS). DESIGN AND SETTING: Consecutive clinical study in a general intensive care unit of a university hospital. PATIENTS: Twelve adult patients with MODS requiring CHDF. MEASUREMENTS AND RESULTS: A total of 68 samples were collected during CHDF for ketamine, norketamine, and midazolam assays. The clearance values for ketamine and norketamine were 10.8 +/- 6.6 and 10.9 +/- 11.5 ml/min and their daily extractions were 21.4 +/- 7.1 and 10.2 +/- 11.5 mg/day, respectively. Midazolam was not eliminated through the filter during CHDF. There were no changes in Ramsay Sedation Score or Glasgow Coma Scale during CHDF. CONCLUSIONS: Small fractions of ketamine and norketamine were eliminated during CHDF in MODS. Midazolam was not eliminated during CHDF. CHDF did not affect the sedation using ketamine and midazolam even in MODS patients.

Analgesics↗
PubMed2001

Spasmolytic effect of magnesium sulfate on serotonin-induced pulmonary hypertension and bronchoconstriction in dogs.

BACKGROUND: Magnesium (Mg2+) has relaxant effects on histamine-induced bronchoconstriction. In addition, Mg2+ has been reported to reduce vascular smooth muscle tone and be clinically useful for treatment of persistent pulmonary hypertension of the newborn. In this study, we evaluated the relaxant effect of Mg2+ on serotonin (5HT)-induced bronchoconstriction and pulmonary hypertension. METHODS: Seven mongrel dogs were anesthetized with pentobarbital (30 mg x kg(-1) + 2 mg x kg(-1) x h(-1)) and paralyzed by pancuronium (0.2 mg x kg(-1) x h(-1)). Bronchoconstriction and pulmonary hypertension were elicited with 5HT (10 microg x kg(-1) + 1 mg x kg(-1) x h(-1)). Airway caliber was evaluated by changes in bronchial cross-sectional area (BCA) of the 3rd bronchial bifurcation measured by a fiberoptic bronchoscope method as previously reported. Pulmonary hypertension was assessed by changes in pulmonary vascular resistance (PVR). The BCA and PVR were expressed as per cent of the basal level. Thirty minutes after start of 5HT infusion, magnesium sulfate (MgSO4): 0 (saline), 1, 10, 100 and 1000 micromol x kg(-1) was given i.v.. Arterial blood was also collected to measure plasma level of Mg2+ and catecholamines. RESULTS: 5HT increased %PVR to 163+/-25% and decreased % BCA by 39.2+/-4.5%. Plasma level of Mg2+ following MgSO4 1000 micromol x kg(-1) i.v. exceeded its toxic level. The ED50s of MgSO4 (dose producing 50% relaxation of maximal constriction) was 47.8 micromol x kg(-1) and 1.09 mmol x kg(-1) for pulmonary hypertension and bronchoconstriction, respectively. The ratio of %PVR to %SVR was about 1.0 after MgSO4 0-100 micromol x kg(-1) i.v., although the ratio significantly increased after 1000 micromol x kg(-1) i.v.. CONCLUSION: In dogs, 5HT-induced pulmonary hypertension but not bronchoconstriction was significantly reduced by an iv bolus of MgSO4, resulting in a plasma concentration within the assumed therapeutic level.

Animals↗
PubMed2001

Use of olprinone, a phosphodiesterase III inhibitor, in an asthmatic patient.

Phosphodiesterase (PDE) III exists in airway smooth muscles. In addition, PDEIII inhibitors have been suggested to relax airway smooth muscle by increasing intracellular cAMP concentrations. We report a successful use of olprinone, a PDEIII inhibitor, for treatment of an asthmatic attack. A 15-year-old male patient treated with oral theophylline 400 mg x d(-1) was anesthetized with propofol, fentanyl and ketamine for knee joint surgery. Immediately after tracheal intubation, an asthma attack occurred with peak airway pressure (Paw)>40 cmH2O. Thus, propofol 20 mg was additionally given to increase anesthetic depth, and Paw gradually decreased to 30 cmH2O. In addition, we started monitoring bronchial cross-sectional area using a superfine fiberoptic bronchoscopic method previously reported. However, as Paw did not further decrease for 30 min, olprinone was intravenously infused (10 microg x kg(-1) x 10 min(-1) + 0.3 microg x kg(-1) x min(-1), total 5 mg). Olprinone infusion rapidly decreased peak Paw from 30 cmH2O to 24 cmH2O and increased bronchial cross-sectional area by 50%. These findings suggest that olprinone produced bronchodilation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2001

Orexin A and B evoke noradrenaline release from rat cerebrocortical slices.

1. Orexin A and B, recently identified in the rat hypothalamus are endogenous neuropeptide agonists for the G-protein coupled orexin-1 (OX1) and orexin-2 (OX2) receptors. 2. In the present study, we have examined the effects of orexin A, B and raised extracellular K(+) on noradrenaline release from the rat cerebrocortical slice. We have compared this with other sleep-wake-related (excitatory) neurotransmitters; dopamine, glutamate, serotonin and histamine. 3. Neurotransmitter release studies were performed in rat cerebrocortical slices incubated in modified Krebs buffer (with and without Ca(2+)+EGTA 1 mM) with various concentrations of orexin A, B and K(+) for various times. 4. Orexin A and B-evoked (10(-7) M) noradrenaline release was time-dependent reaching a maximum some 10 min after stimulation. K(+) (40 mM) evoked release was also time dependent but reached a maximum after 6 min. Orexin A, B and K(+) stimulation of release was concentration dependent with pEC(50) and E(max) (% of basal) values of 8.74+/-0.32 (1.8 nM) and 263+/-14% and 8.61+/-0.38 (2.4 nM) and 173+/-7% and 1.43+/-0.02 (37 mM) and 1430+/-70%, respectively. Orexin-evoked release was partially extracellular Ca(2+) dependent. 5. Of the other transmitters studied there was a weak orexin A and B stimulation of glutamate release. In contrast K(+) evoked dopamine, glutamate, histamine and serotonin release with pEC(50) and E(max) (% of basal) values of 1.47+/-0.05 (34 mM) and 3430+/-410%, 1.38+/-0.04 (42 mM) and 1240+/-50%, 1.47+/-0.02 (34 mM) and 480+/-10% and 1.40+/-0.05 (40 mM) and 560+/-60% respectively. 6. We conclude that the neuropeptides orexin A and B evoke noradrenaline release from rat cerebrocortical slices.

Animals↗
PubMed2001

Plasma cytokine response to surgical stress in schizophrenic patients.

Schizophrenic patients are reported to have immunological dysfunction, however, the immune response to surgery in schizophrenic patients remains unclear. We measured plasma interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) before, during and after colectomy, hemicolectomy and sigmoidectomy in 25 chronic schizophrenic patients (Group S) and 25 control patients (Group C) using ELISA assays. We could find no significant difference in the baseline plasma concentrations of IL-6, IL-8 and TNF-alpha between Group S and Group C. Plasma IL-6 concentrations (32.1 (30.3) and 15.8 (9.6) pg/ml) in Group S at the end of the operation and 24 h after surgery were significantly lower than 76.9 (37.1) and 35.1 (21.5) pg/ml of Group C. Plasma IL-8 concentration (6.1 (2.8)) in Group S at the end of the operation was significantly lower than 8.7 (4.2) pg/ml of Group C. There were no significant changes in plasma TNF-alpha concentration throughout the study period in either group. Plasma cortisol concentrations of schizophrenic patients during surgery were significantly lower than those of control patients. The plasma IL-6 concentrations correlated with plasma cortisol concentrations in either group. We conclude that proinflammatory cytokine response to abdominal surgery is inhibited in schizophrenic patients.

Adult↗
PubMed2001

Effects of isoflurane and ketamine on sleep in rabbits.

The postoperative sleep disturbance (POSD) is characterized by reduction of sleep after surgical operation. However, its mechanism is not well known. Therefore, we hypothesized that anesthetics could contribute to the POSD, and studied the effects of isoflurane and ketamine on sleep in rabbits. Rabbit sleep was measured for 21 h after isoflurane exposure or intravenous injection of ketamine. Non-rapid eye movement sleep (NREMS) was decreased after isoflurane anesthesia. In contrast, ketamine anesthesia significantly enhanced NREMS. Both anesthetics did not affect rapid eye movement sleep. These results suggest that isoflurane may contribute to the POSD, but ketamine may decrease the POSD.

Anesthetics, Dissociative↗
PubMed2001

Comparison of relaxant effects of propofol on methacholine-induced bronchoconstriction in dogs with and without vagotomy.

Propofol has been suggested to have in vivo airway relaxant effects, although the mechanism is still unclear. In this study, we determined whether propofol could antagonize methacholine-induced bronchoconstriction and determined whether vagotomy modifies this relaxant effect. Fourteen mongrel dogs anaesthetized with pentobarbital and pancuronium were assigned to a control group (n=7) and a vagotomy group (n=7). The trachea was intubated with a special endotracheal tube that had a second lumen for insertion of the bronchoscope. Bronchial cross-sectional area, which was monitored continuously through the bronchoscope, was measured with image analysis software. Bronchoconstriction was elicited with methacholine (0.5 microg kg(-1) + 5.0 microg kg(-1) min(-1)) until the end of the experiment. Thirty minutes after the start of methacholine infusion, propofol 0, 0.2, 2.0 and 20 mg kg(-1) was administered. Changes in bronchial cross-sectional area were expressed as percentages of the basal area. Plasma concentrations of propofol and catecholamine were measured by high-performance liquid chromatography. Maximal inhibition (bronchoconstriction = 0%, baseline = 100%) and IC50 (concentration producing 50% inhibition of maximal effect) produced by propofol was obtained from each concentration-response curve using a curve-fitting program. Methacholine decreased bronchial cross-sectional area to 49.3% (95% confidence interval 38.5-60.1%) and 45.3% (34.8-55.7%) of the baseline value. Propofol 20 mg kg(-1) significantly reversed this effect: bronchial cross-sectional area was reduced to 77.8% (66.2-89.6%) and 75.9% (64.0-87.9) in the control and vagotomy groups respectively. The two groups did not differ significantly in the maximal inhibitory effect of propofol [control group, 61.1% (46.3-75.9%), vagotomy group, 64.2% (40.1-88.3%)] or pIC50 [control group 5.03 (4.55-5.51), vagotomy group 4.86 (4.49-5.24)]. Therefore, the relaxant effects of propofol on methacholine-induced bronchoconstriction may not be mediated centrally. Propofol may relax airway smooth muscles directly or through the peripheral vagal pathway.

Anesthetics, Intravenous↗
PubMed2001

Can initial distribution volume of glucose predict hypovolemic hypotension after radical surgery for esophageal cancer?

UNLABELLED: We recently reported that the initial distribution volume of glucose (IDVG) reliably measures the central extracellular fluid volume in the presence or absence of fluid gain or loss. We examined which variables, including IDVG, can predict subsequent hypovolemic hypotension produced by the continuous shift of the extracellular fluid from the central to the peripheral compartment early after radical surgery for esophageal cancer. IDVG and plasma volume were calculated after measuring cardiac index (CI), central venous pressure, and pulmonary artery wedge pressure immediately after admission to the intensive care unit. Intraoperative fluid balance and urine volume were also recorded. Postoperative hypovolemic hypotension was clinically defined as systolic blood pressure < 80 mm Hg responsive to IV fluid administration. Either IDVG < 105 mL/kg or CI < 3.4 L. min(-1). m(-2) was associated with subsequent hypovolemic hypotension (P = 0.002 for the former and P = 0.00 03 for the latter), while remaining variables were not. IDVG and CI were well correlated (r = 0.8 7, n = 25, P = 0.0001). Our results suggest that IDVG can help predict the subsequent hypovolemic hypotension early after radical surgery for esophageal cancer. IMPLICATIONS: Routine cardiovascular variables immediately after major surgery cannot predict the subsequent hypovolemic hypotension produced by the shift of the extracellular fluid. Glucose dilution using glucose 5 g and a one-compartment model can predict it simply and rapidly.

Adult↗
PubMed2001

A comparison of the relaxant effects of olprinone and aminophylline on methacholine-induced bronchoconstriction in dogs.

UNLABELLED: IV aminophylline, a nonselective phosphodiesterase (PDE) inhibitor, is often used to treat an asthma attack during anesthesia. However, in some instances, aminophylline-resistant attacks are observed. Selective PDE3 inhibitors are now clinically available and have been reported to produce bronchodilation. Thus, we compared the relaxant effects of olprinone, a novel PDE3 inhibitor, and aminophylline on methacholine-induced bronchoconstriction. Dogs were anesthetized with pentobarbital. Bronchoconstriction was elicited with methacholine (0.5 microg/kg + 5.0 microg. kg(-1). min(-1)) and assessed as percentage of changes in the bronchial cross-sectional area (BCA; basal = 100%) monitored by bronchoscope. Initially, the relaxant effects of olprinone (n = 8; 0-1000 microg/kg) and aminophylline (n = 8; 0-50 mg/kg) were compared. The bronchial cross-sectional areas were assessed before and 30 min after methacholine infusion began and 5 min after each dose of olprinone or aminophylline. We then determined whether propranolol (0.4 mg/kg) reversed the relaxation induced by olprinone (1000 microg/kg) and aminophylline (50 mg/kg). Olprinone and aminophylline dose-dependently antagonized bronchoconstriction by 56.2% +/- 21.3% (SD) and 68.0% +/- 30.3% with -log 50% effective dose (mean) of 4.80 +/- 0.38 (15.8) microg/kg and 1.96 +/- 0.42 (10.9) mg/kg, respectively. Aminophylline 50 mg/kg significantly increased plasma epinephrine, whereas olprinone did not. In addition, propranolol significantly reduced aminophylline-induced relaxation, but not olprinone-induced relaxation. Therefore, the relaxant effects of olprinone are independent of plasma epinephrine, whereas aminophylline effects may partially result from increased circulating concentrations of epinephrine. IMPLICATIONS: We compared the relaxant effects of olprinone and aminophylline on methacholine-induced bronchoconstriction in dogs. The relaxant effects of olprinone are independent of plasma epinephrine, whereas the aminophylline effects may be partly caused by an increase in plasma epinephrine.

Aminophylline↗
PubMed2001

The relationship between pneumatic tourniquet time and the amount of pulmonary emboli in patients undergoing knee arthroscopic surgeries.

Near-fatal pulmonary embolism can occur immediately after tourniquet release after orthopedic surgeries. In this study, we determined the relationship between tourniquet time and the occurrence of pulmonary emboli in 30 patients undergoing arthroscopic knee surgeries, by using transesophageal echocardiography. The right atrium (RA) was continuously monitored by transesophageal echocardiography, and the number of emboli present was assessed with the following formula: Amount of emboli = 100 x [(total embolic area in the RA after tourniquet release) - (total area of emboli or artifact in the RA before tourniquet release)]/(RA area). The area was assessed 0-300 s after tourniquet release by using image-analysis software. The peak amount of emboli appeared approximately 50 s after tourniquet release. In addition, there was a significant correlation between amount of emboli (Ae [%]) and tourniquet time (Ttq [min]): (Ae = 0.1 x Ttq - 1.0, r = 0.795, P < 0.01). This study suggests that acute pulmonary embolism may occur within 1 min of tourniquet release and that the number of emboli is dependent on Ttq.

Adult↗
PubMed2001

Density detection in dependent left lung region using transesophageal echocardiography.

BACKGROUND: Densities in dependent lung regions worsen oxygenation in patients with acute respiratory distress syndrome. Identification of these densities requires examination using computed tomography (CT). In this study, the authors evaluated the use of transesophageal echocardiography (TEE) to estimate densities in the dependent lung. METHODS: Forty consecutive patients with acute lung injury or acute respiratory distress syndrome who underwent CT and TEE examination were included in this study. Densities in the lower left lung area were detected through the descending aorta by TEE. Density areas observed by TEE were compared with those obtained by CT. The effect of positive end-expiratory pressure (PEEP) application on density area was also evaluated. RESULTS: Density areas in the dependent lung region measured by TEE were 12.0+/-6.1 cm2 (mean +/- SD) at mid esophageal position. Density areas evaluated using TEE in the left lung correlated significantly with those estimated with CT in the left and right lungs (P < 0.01 in both lungs). In addition, the authors observed a significant correlation between PaO2/FIO2 and density areas estimated using TEE (P < 0.05). During positive end-expiratory pressure application, the area of density estimated with TEE decreased and PaO2 improved. CONCLUSIONS: The authors clearly demonstrated that it is possible to estimate the density area of the dependent left lung regions in patients with acute lung injury or acute respiratory distress syndrome using TEE. It is also possible to observe the changes of density areas during application of positive end-expiratory pressure.

Adult↗
PubMed2001

Recovery of intraoperative microbicidal and inflammatory functions of alveolar immune cells after a tobacco smoke-free period.

BACKGROUND: Tobacco smoking inhibits alveolar macrophage function, but cessation of smoking markedly reduces the risk of postoperative pulmonary complications. The authors therefore evaluated the effect of nonsmoking duration on both antimicrobial and inflammatory functions of alveolar macrophages during anesthesia and surgery. METHODS: The authors studied 15 patients who had never smoked, 15 current smokers, and 41 former smokers, all of whom underwent general anesthesia. Former smokers were further allocated to one of three groups depending on their smoke-free periods: 2 months (n = 13), 3-5 months (n = 13), and 6-12 months (n = 15). Alveolar immune cells were collected by bronchoalveolar lavage immediately after induction of anesthesia, at 2 and 4 h after induction of anesthesia, and at the end of surgery. Opsonized and nonopsonized phagocytosis were measured. Microbicidal activity was determined as the ability of the macrophages to kill Listeria monocytogenes directly. Finally, we determined the expression of proinflammatory cytokines, including interleukin 1beta, interleukin 8, interferon gamma, and tumor necrosis factor alpha, and of antiinflammatory cytokines (interleukin 4 and 10) by semiquantitative polymerase chain reaction. RESULTS: Nonopsonized and opsonized phagocytosis and microbicidal activity of alveolar macrophages (antimicrobial functions) decreased 20-50%, and the expression of genes for all proinflammatory and antiinflammatory cytokines increased 3-30-fold over time in all groups. Starting 4 h after induction of anesthesia, the decreases in antimicrobial functions were 1.5-3 times greater in current and former smokers (2 months' abstinence) than in patients who had never smoked. Starting 4 h after anesthesia, the increase in expression of all cytokines, except interleukin 8, was twofold to fivefold less in current and former smokers (2-6 months' abstinence) than in patients who had never smoked. CONCLUSION: Our data suggest that former smokers may have a limited ability to mount effective pulmonary immune defenses for long as 6 months after stopping cigarette use.

Adult↗
PubMed2001

Preoperative intradermal acupuncture reduces postoperative pain, nausea and vomiting, analgesic requirement, and sympathoadrenal responses.

BACKGROUND: In a controlled and double-blind study, the authors tested the hypothesis that preoperative insertion of intradermal needles at acupoints 2.5 cm from the spinal vertebrae (bladder meridian) provide satisfactory postoperative analgesia. METHODS: The authors enrolled patients scheduled for elective upper and lower abdominal surgery. Before anesthesia, patients undergoing each type of surgery were randomly assigned to one of two groups: acupuncture (n = 50 and n = 39 for upper and lower abdominal surgery, respectively) or control (n = 48 and n = 38 for upper and lower abdominal surgery, respectively). In the acupuncture group, intradermal needles were inserted to the left and right of bladder meridian 18-24 and 20-26 in upper and lower abdominal surgery before induction of anesthesia, respectively. Postoperative analgesia was maintained with epidural morphine and bolus doses of intravenous morphine. Consumption of intravenous morphine was recorded. Incisional pain at rest and during coughing and deep visceral pain were recorded during recovery and for 4 days thereafter on a four-point verbal rating scale. We also evaluated time-dependent changes in plasma concentrations of cortisol and catecholamines. RESULTS: Starting from the recovery room, intradermal acupuncture increased the fraction of patients with good pain relief as compared with the control (P < 0.05). Consumption of supplemental intravenous morphine was reduced 50%, and the incidence of postoperative nausea was reduced 20-30% in the acupuncture patients who had undergone either upper or lower abdominal surgery (P < 0.01). Plasma cortisol and epinephrine concentrations were reduced 30-50% in the acupuncture group during recovery and on the first postoperative day (P < 0.01). CONCLUSION: Preoperative insertion of intradermal needles reduces postoperative pain, the analgesic requirement, and opioid-related side effects after both upper and lower abdominal surgery. Acupuncture analgesia also reduces the activation of the sympathoadrenal system that normally accompanies surgery.

Abdomen↗
PubMed2001

Unventilated airway is time-dependently constricted in paralyzed dogs.

BACKGROUND: Apnea has been reported to produce bronchoconstriction and to cause hypoxia, hypercapnia, and modulation of vagal afferent nerves, which also change airway tone. In this study, the authors determined the mechanism of apnea-induced bronchoconstriction. METHODS: Twenty-eight dogs anesthetized and paralyzed were assigned to four groups (n = 7 each): apnea after artificial ventilation with 50% and 100% O2 groups (apnea-50% O2 and apnea-100% O2 groups, respectively), an apnea plus vagotomy group (fraction of inspired oxygen [FiO2] = 1.0), and a one-lung ventilation group (FiO2 = 1.0). The trachea was intubated with a single- or double-lumen tube in the three apnea groups or the one-lung ventilation group, respectively. The bronchial cross-sectional area (BCA) was assessed by the authors' bronchoscopic method. In the apnea-100% O2 and apnea plus vagotomy groups, a respirator was turned off for 5 min to produce apnea. In the apnea-50% O2 group, apnea was produced for 3 min. In the one-lung ventilation group, the right lumen was blocked for 5 min, and 15 min later, the left lumen was blocked for 5 min. BCA, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) were assessed every minute. RESULTS: The BCA in intact dogs time-dependently decreased by approximately 20% and 40% at 3 and 5 min after apnea started, respectively, whereas they did not in vagotomized dogs. In the apnea-50% O2 and apnea-100% O2 groups, bronchoconstriction could occur without hypoxemia, although hypercapnia was observed in all dogs. In the one-lung ventilation group, despite the fact that PaCO2 increased by only 2 mmHg without hypoxemia, unventilated BCA time-dependently decreased by 33.6 +/- 10.3%, whereas ventilated BCA did not. CONCLUSION: The current study suggests that the unventilated airway may constrict spontaneously. In addition, the airway constriction could be vagally mediated but not due to hypoxia and hypercapnia.

Animals↗
PubMed2001

Bronchoconstrictive and relaxant effects of lidocaine on the airway in dogs.

OBJECTIVE: Intravenous lidocaine commonly is used to treat ventricular arrhythmias and to attenuate reflex airway constriction and intracranial pressure elevation during airway manipulation in intensive care units. There is much controversy as to the actions of lidocaine on the airway, so the aim of this study was to compare, in detail, the actions of lidocaine with those of bupivacaine and procaine on airway caliber and the associated changes in plasma catecholamine concentrations in the dog. DESIGN: Prospective, randomized, controlled experimental in vivo and in vitro study. SETTING: A university research laboratory. SUBJECTS: Mongrel dogs. INTERVENTIONS: In the first experiment, we evaluated the effects of intravenous local anesthetics--lidocaine 0-10 mg/kg (n = 7), bupivacaine 0-2.5 mg/kg (n = 7), or procaine 0-20 mg/kg (n = 7)--on basal airway tone. In second experiment, histamine (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 6), serotonin (10 microg/kg + 500 microg x kg(-1) x hr(-1), n = 7), and methacholine (0.5 microg/kg + 300 microg x kg(-1) x hr(-1), n = 7) were infused to determine the effects of lidocaine (0-10 mg/kg) on agonist-induced bronchoconstriction. In addition, the actions of lidocaine on vagal nerve stimulation were examined (n = 7). MEASUREMENTS AND MAIN RESULTS: Bronchial cross-sectional area at the third bronchial bifurcation of dogs was monitored continuously through a fiberoptic bronchoscope. In the first experiment, all local anesthetics produced a dose-dependent decrease in basal bronchial cross-sectional area. In the second experiment, lidocaine significantly potentiated histamine and serotonin-induced bronchoconstriction. In contrast, lidocaine antagonized methacholine- and vagal nerve stimulation-induced bronchoconstriction. CONCLUSION: We have clearly demonstrated that lidocaine may produce direct bronchoconstriction and worsen some agonist-induced bronchoconstriction, but it prevents reflex airway constriction. Therefore, we suggest that this agent be used with caution in asthmatics.

Anesthetics, Local↗