Tatsusuke Yoshikawa

Sleep apnea in patients with acute myocardial infarction

ObjectiveTo document sleep apnea in the acute phase of myocardial infarction. If apnea occurs in patients with myocardial infarction, hypoxemia induced by apnea might exaggerate insufficiency of oxygen supplied to the damaged myocardium. DesignProspective controlled study. SettingCritical care unit of a teaching hospital. PatientsForty-nine patients, average age 64 yrs (range 49 to 91). Measurements and Main ResultsPatient measurements were recorded on a polygraph using an apnea-monitor, pulse oximeter, pulmonary artery pressure monitor, and an ECG. All of the patients observed showed frequent apneic episodes. The apnea was especially frequent when the cardiac index was low. Capillary oxygen saturation of <90% (suggesting systemic hypoxia) was observed in 21 patients concomitantly with apnea. Occasionally, arrhythmias followed these episodes (premature supraventricular contractions [n = 10], premature ventricular contraction [n = 4], and ventricular tachycardia [n = 2]). ConclusionsThis study suggests that sleep apnea is common in the setting of acute myocardial infarction. It may be a factor predisposing to, or even causing, sudden death in patients in the acute phase of myocardial infarction. (Crit Care Med 1991; 19:938)

The effects of diltiazem on hemodynamics and seizure duration during electroconvulsive therapy.

Electroconvulsive therapy (ECT) is often associated with acute hyperdynamic responses, and we hypothesize that diltiazem can blunt this response. We measured the effect of a 10-mg dose of diltiazem on heart rate and mean arterial pressure during ECT. Furthermore, we assessed seizure duration by using both the cuff method and two-lead electroencephalogram. We studied 18 patients with a randomized, double-blinded, placebo-controlled cross-over study design. Diltiazem significantly reduced heart rate and mean arterial pressure just after medication, and it also significantly reduced the increases in these variables after ECT, as compared with the placebo. The use of diltiazem was, however, associated with a shortened seizure duration, possibly making ECT less effective. Because of the reduction in seizure duration, the routine administration of diltiazem may not be advisable because it can possibly interfere with the psychotherapeutic efficacy of ECT. However, diltiazem medication for ECT is potentially useful for reducing tachycardia and hypertension in high-risk patients.

Intravenous verapamil blunts hyperdynamic responses during electroconvulsive therapy without altering seizure activity.

IMPLICATIONS A dose of 0.1 mg/kg of verapamil, administered immediately before anesthesia, significantly reduces the increase in peak heart rate and mean arterial blood pressure after electroconvulsive therapy. Furthermore, the administration of verapamil does not reduce the duration of the seizure.

Intravenous colforsin daropate, a water-soluble forskolin derivative, prevents thiamylal-fentanyl-induced bronchoconstriction in humans

Objective Forskolin, a direct activator of adenylate cyclase, can relax airway smooth muscle, similar to other agents that increase intracellular cyclic adenine monophosphate. However, the potential usefulness of forskolin in treating bronchospasm is limited by its poor water solubility. Colforsin daropate is a novel and potent water-soluble forskolin derivative. No clinical data have been published on the bronchorelaxant effects of this drug. The aim of this study was to investigate whether intravenous colforsin daropate prevents thiamylal-fentanyl-induced bronchoconstriction. Design Double-blind, prospective, placebo-controlled randomized study. Setting University teaching hospital. Patients Thirty-six patients were allocated randomly to two groups: the control group (n = 18) and colforsin daropate group (n = 18). Interventions Intravenous administration of colforsin daropate or placebo (normal saline). Measurements and Main Results Anesthesia was induced with thiamylal 5 mg/kg and vecuronium 0.3 mg/kg. A 15 mg·kg−1·hr−1 continuous infusion of thiamylal followed anesthetic induction. Controlled ventilation was maintained, delivering 50% nitrous oxide in oxygen. Twenty minutes after the induction of anesthesia, the control group patients started to receive 7.5 mL/hr continuous infusion of normal saline, and the colforsin daropate group patients started to receive 0.75 &mgr;g·kg−1·min−1 (7.5 mL/hr) continuous infusion of colforsin daropate for 60 min. After that, both groups received fentanyl 5 &mgr;g/kg. Systolic and diastolic arterial pressure, heart rate, mean airway resistance (Rawm), expiratory airway resistance (Rawe), and dynamic lung compliance (Cdyn) were measured at the baseline, just before the administration of fentanyl (T30), at three consecutive 6-min intervals after fentanyl injection (T36, T42, and T48) and 30 min after fentanyl injection (T60). At baseline, both groups had comparable Rawm, Rawe, and Cdyn values. In the control group, Rawm increased significantly at T36–60 compared with the baseline, Rawe increased significantly at T36–48 compared with the baseline, and Cdyn decreased significantly at T36–60 compared with the baseline. In the colforsin daropate group, there were no changes in Rawm, Rawe or Cdyn at T36–60. Conclusions These observations suggest that intravenous colforsin daropate has a bronchodilator effect in humans.

Oral tizanidine, an α2-Adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane in human adults

UNLABELLED Tizanidine, an alpha2-adrenoceptor agonist, has an antinociceptive effect in animals. In humans premedicated with oral tizanidine, the increase in blood pressure associated with laryngoscopy and intubation was attenuated, and the amount of midazolam required for loss of consciousness was significantly reduced. We speculated that the oral administration of tizanidine might reduce the minimum alveolar anesthetic concentration (MAC) of sevoflurane. Fifty-two ASA physical status I-II patients, aged 24-56 yr, were randomly allocated into two groups: a Control group (n = 26) and a Tizanidine group (n = 26). As premedication, the Control group received a placebo, and the Tizanidine group received 4 mg of oral tizanidine 90 min before surgical skin incision. Anesthesia was induced in all patients by using vital capacity rapid inhaled induction with sevoflurane (5%). Loss of consciousness was defined as both the loss of the eyelid reflex and the lack of a response to a verbal command. MAC was determined by a technique adapted from the conventional up-down method for quantal responses. The MAC of sevoflurane was 2.2% +/- 0.2% in the Control group and 1.8% +/- 0.2% in the Tizanidine group (P = 0.0004). The time to loss of consciousness in the Tizanidine group (60.2 +/- 22.5 s) was significantly shorter than that in the Control group (73.7 +/- 26.3 s) (P = 0.03). The oral administration of tizanidine 4 mg successfully reduced the MAC of sevoflurane by 18% in human adults. IMPLICATIONS Oral tizanidine (4 mg), an alpha2-adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane by 18%.

Changes in hemodynamic variables and catecholamine levels after rapid increase in sevoflurane or isoflurane concentration with or without nitrous oxide under endotracheal intubation

AbstractPurpose. Rapid increases in concentrations of isoflurane and desflurane in oxygen have been shown to increase sympathetic activity. The aim of this study was to determine whether concomitant administration of nitrous oxide would reduce these sympathomimetic effects of volatile anesthetics. Methods. Eighty healthy patients in whom the trachea was intubated and mechanically ventilated were given 15 min of anesthesia with either N2O (67%)-O2-sevoflurane (GOS), O2-sevoflurane (OS), N2O (67%)-O2-isoflurane (GOI), or O2-isoflurane (OI) (n = 20 per group). The inspired concen-tration of sevoflurane was 0.85% (0.5 minimum alveolar concentration [MAC]), and that of isoflurane was 0.6% (0.5 MAC). Fifteen minutes after endotracheal intubation, baseline and arterial blood sample data were obtained. Immediately after that, a sudden administration of 2.9 MAC volatile anesthetics was performed. Systolic and diastolic arterial pressures, heart rate, and end-tidal carbon dioxide concentration were obtained at 0.5, 1, 1.5, 2, 3, 4, and 5 min after that. To measure catecholamine levels, arterial blood samples were obtained 2 and 5 min after the trial started. Results. Except for the OI group, systolic and diastolic arterial pressure progressively decreased after the abrupt increase in the concentration of volatile anesthetics. Except for the OS group, the heart rate increased after the abrupt increase in the concentration of volatile anesthetics. In the OI group, the end-tidal concentration of carbon dioxide increased at 0.5 and 1 min, suggesting that a slight hyperdynamic state occurred. However, it decreased progressively after the abrupt increase in volatile anesthetic concentration in the other groups. Plasma norepinephrine levels increased progressively in all groups. Conclusion. Even if nitrous oxide was added to isoflurane or sevoflurane, the increase in heart rate could not be avoided. Contrary to previous reports, severe hyperdynamic circulation was not observed after a rapid increase in isoflurane concentration.

Intravenous nicorandil prevents thiamylal-fentanyl-induced bronchoconstriction in humans.

ObjectiveNicorandil has a hybrid property between nitrates and potassium channel openers and has been reported to cause a concentration-dependent relaxation of isolated guinea pig trachealis. Experimental asthma in a guinea pig model was also inhibited by nicorandil. However, no clinical data on the bronchorelaxant effects of this drug have been published. The aim of this study was to investigate whether intravenous nicorandil prevents thiamylal-fentanyl–induced bronchoconstriction. DesignDouble-blind, prospective, placebo-controlled, randomized study. PatientsA total of 36 patients were randomly allocated to two groups: a control group (n = 18) and a nicorandil group (n = 18). InterventionsIntravenous administration of nicorandil or a placebo (normal saline). Measurements and Main ResultsAnesthesia was induced with 5 mg/kg thiamylal and 0.3 mg/kg vecuronium. A continuous infusion of 15 mg·kg−1·hr−1 thiamylal was then used to maintain the anesthesia. Controlled ventilation was maintained, delivering 50% nitrous oxide in oxygen. At 20 mins after the induction of anesthesia, the control group patients were given a 6 mL/hr continuous infusion of normal saline and the nicorandil group patients were given a 6 mg·hr−1 (6 mL/hr) continuous infusion of nicorandil for 60 mins. At 30 mins after the start of the study, both groups received a 5-&mgr;g/kg dose of fentanyl. Systolic and diastolic arterial pressure, heart rate, mean airway resistance, expiratory airway resistance, and dynamic lung compliance were measured for the baseline condition, just before the administration of fentanyl (T30), at three consecutive 6-min intervals after the fentanyl injection (T36, T42, and T48) and 30 mins after the fentanyl injection (T60). Both groups had comparable baseline values for mean airway resistance, expiratory airway resistance, and dynamic lung compliance. In the control group, both mean airway resistance and expiratory airway resistance increased significantly at T36–60, compared with the baseline values, and dynamic lung compliance decreased significantly at T36–60, compared with the baseline value. In the nicorandil group, no changes in mean airway resistance, expiratory airway resistance, or dynamic lung compliance occurred at T36–60. ConclusionsOur observations suggest that the intravenous administration of nicorandil has a bronchodilator effect in humans.

Effect of Prophylactic Bronchodilator Treatment with Intravenous Colforsin Daropate, a Water-soluble Forskolin Derivative, on Airway Resistance after Tracheal Intubation

Background After induction of anesthesia, lung resistance increases. The authors hypothesized that prophylactic bronchodilator treatment with intravenous colforsin daropate, a water-soluble forskolin derivative, before tracheal intubation would result in decreased lung resistance and increased lung compliance after tracheal intubation when compared with placebo medication. Methods Forty-six adult patients were randomized to placebo or colforsin daropate treatment. Patients in the control group received normal saline; patients in the colforsin group received 0.75 &mgr;g · kg−1 · min−1 colforsin daropate intravenously until the study ended. Thirty minutes after the study began, the authors administered 5 mg/kg thiamylal and 5 &mgr;g/kg fentanyl for induction of general anesthesia and 0.3 mg/kg vecuronium for muscle relaxation. A 15-mg · kg−1 · h−1 continuous infusion of thiamylal followed anesthetic induction. Four, 8, 12, and 16 min after tracheal intubation, mean airway resistance (Rawm), expiratory airway resistance (Rawe), and dynamic lung compliance (Cdyn) were measured. Results Patients in the colforsin group had significantly lower Rawm and Rawe and higher Cdyn after intubation than those in the control group. Differences in Rawm, Rawe, and Cdyn between the two groups persisted through the final measurement at 16 min. At 4 min after intubation, smokers had a higher Rawm and a lower Cdyn than nonsmokers in the control group. After treatment by intravenous colforsin daropate, Rawm, Rawe, and Cdyn values were similar for smokers and nonsmokers after tracheal intubation. Conclusions Prophylactic treatment with colforsin daropate produced lower Rawm and Rawe and higher Cdyn after tracheal intubation when compared with placebo medication. Pretreatment before intubation may be beneficial and advantageous for middle-aged smokers.

Thoracoscopic lung biopsy in a patient with pulmonary lymphangiomyomatosis.

PurposeWe describe the anesthetic management of a patient with pulmonary lymphangiomyomatosis (LAM) during thoracoscopic lung biopsy (TSLB).Clinical featuresLAM is a rare idiopathic disease characterised by progressive deterioration in respiratory function, occurring almost exclusively in women. In establishing the diagnosis, an open lung biopsy (OLB) has been employed in patients with relatively normal lung function. However, TSLB rather than OLB is less invasive. A 38 yr old woman developed aclinical course of cough, shortness of breath and sputum production, Chest Xray findings,99mTc-MAA scintigraphy and thin-sliced high resolution CT, typical of LAM, TSLB was scheduled to establish the diagnosis. General anesthesia, employing differential lung ventilation and high frequency jet ventilation combined with epidural anesthesia and continuous intravenous propofol was performed successfully. High frequency ventilation was applied to the non-dependent lung and intermittent positive pressure ventilation (IPPV) to the dependent lung with lower tidal volume and respiratory rate, allowing permissive hypercapnia. In the postoperative period, although synchronized intermittent mandatory ventilation was applied, pressure support ventilation or continuous positive airway pressure (CPAP) would have been a better selection. Postoperative sedation was performed satisfactorily using propofol.ConclusionsWe recommend general anesthesia using differential lung ventilation combined with epidural anesthesia and intravenous propofol during TSLB for LAM. Postoperative ventilation should be pressure support ventilation or CPAP to keep peak inspiratory pressure low and allow permissive hypercapnia.RésuméObjectifDécrire la démarche anesthésique entreprise pendant une biopsie pulmonaire pleuroscopique (BPPS) chez une patiente atteinte de lymphangiomyomatose pulmonaire (LAM).Eléments cliniquesLa LAM est une affection idiopathique rare caractérisée par une détérioration progressive de la fonction respiratoire et qui survient presque exclusivement chez les femmes. Pour poser le diagnostic, une biopsie pulmonaire ouverte (BPO) a été utilisée chez des patients dont la fonction pulmonaire était relativement normale. Cependant, la BPPS est moins effractive que la BPO. Une femme de 38 ans a connu une évolution clinique de toux, d’essoufflement et de production de crachat suivis de constatations radiographiques thoraciques typiques d’une LAM lors d’une scintigraphie99mTc-MAA et d’une tomodensitométrie à haute résolution en couche mince. Une BPPS a été prévue pour confirmer le diagnostic. L’anesthésie réussie, comprenant une ventilation pulmonaire différentielle et une ventilation à haute fréquence combinées à une anesthésie péridurale et à l’administration intraveineuse de propofol. La ventilation à haute fréquence a été appliquée au poumon non déclive et la ventilation à pression positive intermittente (VPPI) au poumon déclive avec un volume courant et une fréquence respiratoire plus faibles, ce qui permettait une hypercapnie permissive. Après l’opération, même si une ventilation imposée intermittente synchrone a été appliquée, la ventilation spontanée avec aide inspiratoire ou avec une pression expiratoire positive (VSPEP) auraient constitué de meilleurs choix. La sédation postopératoire avec propofol s’est révélée satisfaisante.ConclusionNous recommandons une anesthésie générale avec une ventilation pulmonaire différentielle combinée à une analgésie épidurale et au propofol intraveineux pendant la BPPS pour la LAM. La ventilation postopératoire devrait être une ventilation spontanée avec aide inspiratoire ou avec une pression expiratoire positive pour conserver une pression inspiratoire maximale basse et accepter une hypercapnie permissive.