Kaoru Koyama

Effects of Sevoflurane, Isoflurane, Enflurane, and Halothane on Left Ventricular Diastolic Performance in Dogs

The effects of volatile anesthetics on active (ventricular relaxation) and passive (chamber stiffness) indices of diastolic function and on left ventricular filling rates in dogs were studied to determine how these agents affect left ventricular diastolic performance. Thirty-five mongrel dogs were randomly assigned to receive sevoflurane, isoflurane, enflurane, or halothane. Left ventricular pressure waveforms, phonocardiograms, and echocardiograms were recorded after administering the anesthetics at concentrations of 0% (control), 1%, 2%, and 3%. Ventricular relaxation was defined as the time constant of the decline in left ventricular pressure. Chamber stiffness was derived from the ventricular pressure-volume relationship during passive filling. Rapid filling rate, slow filling rate, and atrial filling rate were obtained from echocardiograms and phonocardiograms. No change in the time constant or in chamber stiffness was observed at any concentration of sevoflurane or isoflurane. However, the highest studied concentration of enflurane and halothane produced a significant increase in the time constant and in chamber stiffness. Rapid filling rate as well as atrial filling rate decreased significantly with the volatile anesthetics, especially with enflurane and halothane. Sevoflurane and isoflurane did not alter ventricular relaxation or chamber stiffness, but did affect diastolic function as manifested by their alteration of filling rates. In contrast, enflurane and halothane each prolonged ventricular relaxation and increased chamber stiffness. With the administration of the volatile anesthetics, the rapid filling rate decreased with the deterioration of diastolic function; in addition, atrial filling rates decreased and did not compensate for the reduction in early ventricular filling.

Determination of the standard value of circulating blood volume during anesthesia using pulse dye-densitometry: a multicenter study in Japan.

PurposeThe standard value for circulating blood volume (BV) during anesthesia was determined by a multicenter study in Japan. The significance of BV on the reduction of blood pressure after the induction of anesthesia was also examined.MethodsThe study included 184 patients from eight university hospitals. After the induction of anesthesia, pulse dye-densitometry was performed according to a uniform protocol. Factors contributing to reduced blood pressure after induction of anesthesia were examined by multiple logistic regression analysis.ResultsThe mean and standard deviation of BV was 80.0 ± 13.9 ml·kg−1; for females and 84.2 ± 15.3 ml·kg−1 for males (P > 0.05). There was no age difference in terms of BV. After adjusting for the effects of height, weight, and age, the factors predisposing to a reduction in blood pressure of >20 mmHg after induction of anesthesia were found to be age (P < 0.01) and BV (ml·kg−1) ( P < 0.001).ConclusionWe determined the BV of anesthetized patients before surgery in Japan using pulse dye-densitometry. It is suggested that age is not a factor regarding BV, and that blood pressure tends to be reduced in hypovolemic patients after induction of anesthesia.

Tension pneumothorax resulting in cardiac arrest during emergency tracheotomy under transtracheal jet ventilation.

A 48-year-old man was admitted because of severe dyspnea. The patient was in a healthy condition until one week before, when he noticed dyspnea on exertion. He had a history of thyroid papillary adenocarcinoma for which he had undergone right thyroid lobectomy 10 years ago. After that, tumorectomy for local recurrence has been performed for three times. On admission, he was severely dyspneic with peripheral cyanosis and remarkable stridor. Arterial blood gas analysis in room air showed compensated respiratory acidosis with pH of 7.41, Pao2 of 54 mmHg, and Paco2 of 57 mmHg. His hemoglobin was 14.9 g·dl1 . Chest X-ray revealed severe tracheal stenosis

Anesthetic management of a neonate with Dandy-Walker syndrome.

Dandy-Walker syndrome is a congenital disease characterized by absence of cerebellar vermis and cyst development in the posterior fossa which is connected with the fourth ventricle; it results in enlargement of the posterior fossa and hydrocephalus [1]. We reported the anesthetic management of a neonate with Dandy-Walker syndrome who underwent neurosurgery twice and had prolonged convulsive episodes.