Yasuo Hironaka

Landiolol attenuates tachycardia in response to endotracheal intubation without affecting blood pressure

PURPOSE Beta-adrenergic receptor antagonists (beta-antagonists) have long been used to control perioperative tachyarrhythmias. The effects of a beta(1)-antagonist, landiolol, on perioperative hemodynamics are unknown. We aimed to determine the appropriate dosage of landiolol for the treatment of hemodynamic changes in response to endotracheal intubation. METHODS Sixty-four patients without heart disease or hypertension, were assigned to receive saline (group C) or landiolol (0.1 or 0.3 mg.kg(-1); groups L1 and L3). Anesthesia was induced with propofol (2 mg.kg(-1) iv) followed by saline or landiolol iv. After ventilation with facemask using 2% sevoflurane in 100% oxygen for 90 sec, endotracheal intubation was performed. After intubation, anesthesia was maintained using 1% sevoflurane in combination with 50% nitrous oxide. Values of heart rate and mean arterial blood pressure were recorded before induction to five minutes after intubation. RESULTS In group C, heart rate and mean blood pressure increased simultaneously after tracheal intubation, compared with baseline values. Heart rate values were attenuated immediately before as well as after intubation in group L3, compared with groups C and L1. Heart rate did not increase after tracheal intubation in group L1, compared with baseline. In contrast, mean arterial blood pressure values did not differ among groups. CONCLUSIONS The newly developed beta(1)-antagonist landiolol (0.1 and 0.3 mg.kg(-1)) may help prevent tachycardia without affecting blood pressure during the induction of anesthesia.PurposeBeta-adrenergic receptor antagonists (ß-antagonists) have long been used to control perioperative tachyarrhythmias. The effects of a ß1-antagonist, landiolol, on perioperative hemodynamics are unknown. We aimed to determine the appropriate dosage of landiolol for the treatment of hemodynamic changes in response to endotracheal intubation.MethodsSixty-four patients without heart disease or hypertension, were assigned to receive saline (group C) or landiolol (0.1 or 0.3 mg kg-1; groups L1 andL3). Anesthesia was induced with propofol (2 mg kg-1iv) followed by saline or landiololiv. After ventilation with facemask using 2% sevoflurane in 100% oxygen for 90 sec, endotracheal intubation was performed. After intubation, anesthesia was maintained using 1 % sevoflurane in combination with 50% nitrous oxide. Values of heart rate and mean arterial blood pressure were recorded before induction to five minutes after intubation.ResultsIn group C, heart rate and mean blood pressure increased simultaneously after tracheal intubation, compared with baseline values. Heart rate values were attenuated immediately before as well as after intubation in groupL3, compared with groups C and L1. Heart rate did not increase after tracheal intubation in group L1, compared with baseline. In contrast, mean arterial blood pressure values did not differ among groups.ConclusionsThe newly developed ß1-antagonist landiolol (0.1 and 0.3 mg·kg-1) may help prevent tachycardia without affecting blood pressure during the induction of anesthesia.RésuméObjectifLes antagonistes des récepteurs bêta-adrénergiques (ßantagonistes) ont été longtemps utilisés pour contrôler les tachyarythmies périopératoires. Les effets d’un ß 1-antagoniste, le landiolol, sur ïhémodynamique périopératoire sont inconnus. Nous voulions déterminer le dosage approprié de landiolol pour traiter les changements hémodynamiques provoqués par l’intubation endotrachéale.MéthodeSoixante-quatre patients sans cardiopathie, ni hypertension, ont reçu une solution saline (group C) ou du landiolol (0,1 ou 0,3 mg·kg-1; groupes L1 et L3). L’anesthésie a été induite avec du propofol (2 mg·kg-1 iv) suivi de la solution saline ou du landiolol iv. Après ventilation au masque, avec du sévoflurane à 2 % dans de l’oxygène à 100 pendant 90 s, l’intubation endotrachéale a été réalisée. Puis, l’anesthésie a été maintenue avec du sévoflurane à 1 % combiné à du protoxyde d’azote à 50 %. La fréquence cardiaque et la tension artérielle moyenne ont été enregistrées avant l’induction et jusqu’à cinq minutes après l’intubation.RésultatsDans le groupe C, la fréquence cardiaque et la tension artérielle moyenne ont augmenté simultanément après l’intubation endotrachéale, par rapport aux valeurs de base. La fréquence cardiaque a baissé immédiatement avant et après l’intubation dans le groupe L3 comparé aux groupes C et L1. La fréquence cardiaque n’a pas augmenté, sur les mesures de base, après l’intubation endotrachéale dans le groupe L1. Les valeurs de la tension artérielle moyenne étaient comparables entre les groupes. as]Conclusion p ]Le nouveau ß 1-antagoniste landiolol (0,1 et 0,3 mg·kg-1) peut aider à prévenir la tachycardie sans affecter la tension artérielle pendant l’induction de l’anesthésie.

Effects of isoflurane and sevoflurane anesthesia on arteriovenous shunt flow in the lower limb of diabetic patients without autonomic neuropathy.

Background:Failure of sympathetic nerve control caused by diabetic neuropathy results in vasodilation of arteriovenous shunts. The aim of this study was to test the hypothesis that the function of arteriovenous anastomoses was disordered in mild diabetic patients without apparent neuropathy, and that volatile anesthetics opened arteriovenous shunts more greatly in nondiabetic patients than diabetic patients. Methods:Autonomic system function was assessed by cardiovascular reflex tests. Arterial–venous oxygen content difference (A-V&Dgr;O2) and partial oxygen pressure index (Pvo2/Pao2, the ratio of oxygen tension in femoral vein blood to that in femoral artery blood) were measured before and during isoflurane or sevoflurane anesthesia in 16 diabetic and 22 nondiabetic patients. Skin temperatures of the foot and leg were measured in 14 diabetic and 15 nondiabetic patients using thermography before and during anesthesia. Results:Pvo2/Pao2 before anesthesia was significantly higher in diabetic patients. In nondiabetics, venous oxygen content significantly increased and A-V&Dgr;O2 markedly decreased during anesthesia, but these parameters were unchanged in diabetics. Foot temperatures were higher in diabetics before anesthesia, and increased gradually and significantly in both groups during anesthesia, but with a greater increase in nondiabetic patients. Induction of anesthesia caused a larger decrease in leg temperature in diabetics than in nondiabetics. Conclusions:Diabetic patients have a higher Pvo2/Pao2 and a small core-to-peripheral temperature gradient before anesthesia, suggesting latent dysfunction of the autonomic nerve system, even in the absence of autonomic neuropathy. Volatile anesthesia opens the arteriovenous shunt in nondiabetics to a greater extent than in diabetic patients.

A long endotracheal tube to facilitate intubation via the Fastrach™ laryngeal mask airway

We appreciate Chawla et al.’s interest in our article. Succinylcholine may be associated with an increase in heart rate, corresponding with elevation of plasma norepinephrine.1 Indeed, in the control group in our study, heart rate was significantly elevated one minute after intubation.2 Therefore, it is unlikely that succinylcholine augmented the negative chronotropic response observed in the landiolol groups. However, since we administered vecuronium immediately after intubation, we cannot exclude the possibility that this drug may have attenuated catecholamine release after succinylcholine, resulting in smaller changes in heart rate and blood pressure.1, 2 We recognize that perioperative β–blocker administration to obtain perioperative hemodynamic optimization must be done selectively. The use of short-acting β–blockers including landiolol, may confer specific benefits in the setting of brief, but intense periods of autonomic stimulation in patients with coronary artery disease.