Tetsuya Koyano

A comparative study of the vasodilator effects of prostaglandin E1 in patients with pulmonary hypertension after mitral valve replacement and with adult respiratory distress syndrome

To determine whether the vasodilator effects of prostaglandin E1 (PGE (1)) differ according to the etiology and pathophysiology of pulmonary hypertension, we studied 30 patients with pulmonary hypertension after mitral valve replacement (MVR) (n = 16) or with the adult respiratory distress syndrome (ARDS) (n = 14).PGE (1) was administered to decrease the mean pulmonary artery pressure to below 30 mm Hg in both groups. Cardiac index and oxygen delivery tended to increase, whereas mean systemic artery pressure, mean pulmonary artery pressure, systemic vascular resistance index (SVRI), and pulmonary vascular resistance index (PVRI) significantly decreased in both groups. A vasodilatory index was defined in this study to allow evaluation of vasodilation relative to PGE1 dose: systemic vasodilatory index (VIs) = SVRI change/PGE1 dose; and pulmonary vasodilatory index (VIp) = PVRI change/PGE1 dose. The VIp was similar in both groups, but the VIs was significantly greater in the ARDS group compared with the MVR group (13.3 +/- 7.8 vs 4.8 +/- 5.1, P < 0.01). A good correlation was found between the pretreatment intrapulmonary shunt fraction (Qs/Qt [%]) value and PGE1 extraction rate in the lung (r = 0.60), and between the pretreatment Qs/Qt value and PGE1 concentration in the radial artery (r = 0.65) in an additional 15 patients. We conclude that the vasodilator effects of PGE1 on the pulmonary circulation are similar in the two groups, whereas the vasodilator effects on the systemic circulation are significantly greater in the ARDS group and that significant reduction in VIs in the ARDS group was associated with decreased PGE1 extraction in the lung. Implications: Pulmonary hypertension after mitral valve replacement, or with adult respiratory distress syndrome, is a major medical problem. The authors found that administration of prostaglandin E1 significantly dilated the pulmonary circulation with a concomitant decrease in pulmonary artery pressure. Because the systemic vasodilatory effect was greater in the adult respiratory distress syndrome group, the authors concluded that prostaglandin E1 concentrations in the systemic circulation depend on the severity of lung injury. (Anesth Analg 1997;85:507-13)

Accuracy of carboxyhe-moglobin dilution method for the measurement of circulating blood volume

Purpose: The management of circulating blood volume (BVc) is crucial in intensive care unit (ICU) patients. The purpose of this study was to verify the accuracy and precision of the carbon monoxide-labeled hemoglobin (CO-Hb) dilution method (CO method) by comparing it with the51Cr-labeled erythrocyte dilution method (51Cr method) for the measurement of BVc.Methods: A prospective study was performed in 18 patients who underwent coronary artery bypass grafting (CABG) under mild hypothermic cardiopulmonary bypass (CPB). The BVc was measured by both the CO method and the51Cr method at 24 hr after ICU admission in order to verify the accuracy and precision of the CO method. Paired data were assessed in absolute terms, and percentage errors were calculated by the degree of agreement.Results: Small mean differences and standard deviations between the CO method and the51Cr method (−70.2±184.8 mL) and small percentage errors (−0.49±1.29%) indicated the accuracy and precision of the CO method, and a close correlation was observed (r=0.97).Conclusion: The CO method can measure BVc with a similar degree of accuracy as the51Cr method. It is simple, repeatable and safe without the risk of exposure to radioactivity in the ICU.RésuméObjectif: La gestion du volume du sang circulant (VSc) est cruciale chez les patients des unités de soins intensifs (USI). Nous avons voulu vérfier, pour la détermination du VSc, la justesse et la précision de la méthode de dilution avec oxyde de carbone et hémoglobine marquée (méthode CO) en la comparant à la méthode avec des hématies marquées par le51Cr (méthode51Cr)Méthode: Une étude prospective a été réalisée auprès de 18 patients qui subissaient un pontage aortocoronarien avec circulation extracorporelle (CEC) légèrement hypothermique. Le VSc a été mesuré selon les deux méthodes 24 h après l’admission à l’USI. Les données appariées ont été évaluées en valeur absolue et le pourcentage d’erreur a été calculé par le degré de concordance.Résultats: De faibles différences moyennes et écarts types entre la méthode CO et la méthode51Cr (−70,2±184,8 mL) et de bas pourcentages d’erreur (−0,49±1,29%) ont indiqué la justesse et la précision de la méthode CO, et une corrélation étroite a été observée (r=0,97).Conclusion: La méthode CO peut servir à mesurer le VSc avec un degré d’exactitude semblable à celui de la méthode51Cr. Elle est simple, répétable et sécuritaire, sans risque d’exposition à la radioactivité dans l’USI.

Cardioprotective effects of Lazaroid U-74389G on ischemia-reperfusion injury in canine hearts.

BACKGROUND Lazaroid, an inhibitor of iron-mediated lipid peroxidation, has been shown to reduce free radical-mediated injury after ischemia and reperfusion. The effect of Lazaroid U-74389G was investigated on ischemia-reperfusion injury of the heart through preservation and transplantation (Tx) in dogs. METHODS Eleven pairs of adult mongrel dogs weighing 8.5 to 12 kg formed the recipient-donor combinations. Following electromechanical arrest of the heart using cardioplegia, the coronary vascular beds were washed out with a cold University of Wisconsin solution followed by 12-hour preservation and orthotopic Tx. Experimental animals were divided into 2 groups; 6 pairs formed the control group, and 5 formed the Lazaroid-treated group in which Lazaroid U-74389G at 10 mg/kg was administered intravenously 30 minutes before reperfusion of the heart. The cardiac function including cardiac output, left ventricular (LV) pressure, and LV dp/dt was assessed 2 hours after Tx by comparing it with the recovery rates (%) from cardiac function of donor dogs. Each transplanted heart was harvested for histological study. RESULTS The recovery of cardiac function after Tx was significantly better in the Lazaroid-treated group than in the control group. Histologically, myocardial damage, evaluated by both light and transmission electron microscopy, was less evident in the Lazaroid-treated group than in the control group. CONCLUSION Early cardiac function following Tx was significantly better and histological damage was less in the Lazaroid-treated group than in the control group, suggesting that Lazaroid U-74389G is effective in preventing ischemia-reperfusion injury after preservation and Tx.

PEEP Therapy for Patients With Pleurotomy During Coronary Artery Bypass Grafting

Abstract Severe pulmonary oxygenation impairment resulting from peripheral lung atelectasis occurred in some patients with pleurotomy during the harvest of the internal mammary artery graft followed by coronary artery bypass grafting (CABG). We studied the efficacy of intraoperative positive end‐expiratory airway pressure (PEEP) therapy for the prevention of postoperative pulmonary oxygenation impairment. A total of 66 patients with solitary CABG procedure were included in this study. The pleural cavity was intraoperatively opened in 44 patients and not opened in 22. PEEP therapy was not used in any patient before May 1996 (referred to herein as the former period) and was used more recently in eight patients with pleurotomy (referred to herein as the latter period). PEEP was initiated immediately after pleurotomy during the harvest of the internal mammary artery graft. Without PEEP therapy, values of PaO2, A‐aDO2, and respiratory index (RI) were worse in patients with pleurotomy than in those without pleurotomy. Meanwhile, there were no major differences in these values between patients with or without pleurotomy after the induction of PEEP therapy. Respiratory insufficiency (A‐aDO2 > 400 mmHg and RI > 1.5) was detected in six patients with pleurotomy in the former period. Three of these six patients required over 1 week of long‐term mechanical respiratory support. No respiratory insufficiency occurred in patients of the latter period. In conclusion, PEEP therapy, which is initiated just after pleurotomy, may prevent oxygen impairment and pulmonary atelectasis after extracorporeal circulation (ECC) and is recommended for patients with pleurotomy, especially for patients with preoperative low respiratory function.

Postoperative brain complications following retrograde cerebral perfusion

This study was undertaken to investigate the neurological risk factors associated with the retrograde cerebral perfusion (RCP) technique, by examining the relationship between intraoperative parameters and postoperative brain complications. A total of 12 patients who underwent surgery for thoracic aortic aneurysms using the RCP technique were included in this study. Profound hypothermia was induced through cardiopulmonary bypass which was established with a femoral arterial cannula and bicaval return. During RCP, a venous drainage cannula from the superior vena cava (SVC) was switched over to the arterial return circuit, and oxygenated blood was retrogradely infused through the SVC. The perfusion flow rate was maintained at 273 ± 113 ml/min and the SVC pressure was maintained at 15 ± 6mmHg. The RCP time was 68 ± 27 min with a range of 27–130 min, and the lowest rectal temperature was 16 ± 1°C. The total elapsed time until emergence from anesthesia after the operation was 12 ± 6h. The operation time correlated with the awakening time (r=0.729,P=0.0088). Longer RCP times of up to 101 and 130min tended to result in postoperative brain damage. The lowest rectal temperature also correlated with the awakening time (r=0.697,P=0.0149), and an inverse correlation between the SVC pressure and the awakening time was observed (r=−0.727,P=0.0091). These findings demonstrate the importance of reducing both the RCP and operation times to decrease the incidence of brain damage. If carried out under optimal conditions, including perfusion pressure and brain temperature, RCP could be marginally prolonged safely without causing major neurological complications.

Postoperative infections related to pacing wires, pulmonary Arterial catheters, and drainage tubes temporarily Inserted during open-heart surgery

Bacterial examinations of temporary pacing wires (P-wires), pulmonary arterial (P-A) catheters, and drainage tubes temporarily inserted during open-heart surgery were performed in 213 patients. Bacteria were detected in 19 (2.8%) of 672 specimens gathered from the subject patients, with coagulase-negative Staphylococcus (CNS) being most frequently observed. P-wires accounted for 17 out of 19 of the culture-positive specimens, and 7 of the P-wires remained in place for more than two weeks. The frequency of infection with the P-wires was significantly higher than with the P-A catheters or drainage tubes. The period of time that the P-wire was left in place significantly longer than for P-A catheter or drainage tube. There was, however, no statistically significant difference between the culture-positive and negative groups in respect to age, detention periods, operation times, CPB times, or length of ICU stay. As a result of these findings, we have concluded that P-wires should be removed as soon as possible following surgery, and in any case, a meticulous care should be taken to prevent transcutaneous infection.

What influences the results in critical patients after cardiovascular surgery

The predictive factors of surgical outcome were evaluated in compromised patients following cardiovascular surgery. Of 608 patients undergoing cardiovascular surgery between 1991 and 1999, 55 stayed in the intensive care unit for 2 weeks or longer. The mean age of these 55 patients was 56 years. There were 35 survivors and 20 nonsurvivors. Postoperative respiratory failure and gastrointestinal complications were significantly more frequent in those who died. The survival rate was significantly higher in patients who had enteral feeding compared to those who did not (88% versus 43%). Serum cholinesterase and total cholesterol concentrations were higher in the survivors. It was concluded that postoperative respiratory and gastrointestinal conditions influenced the surgical outcome, and serum cholinesterase and total cholesterol concentrations were valuable predictors of survival.

Changes in gastric intramucosal pH and circulating blood volume following coronary artery bypass grafting

Purpose: To determine the changes in gastric intramucosal pH (pHi) following coronary artery bypass grafting (CABG) in comparison with systemic hemodynamic variables and circulating blood volume (BVc).Methods: Twenty patients who underwent CABG under mild hypothermic cardiopulmonary bypass (CPB) were included. Hemodynamic variables and the values of pHi were obtained at 3, 6, 12 and 24 hr after admission to the intensive care unit (ICU). The pHi was measured by gastric tonometric catheter. The BVc was measured by carbon monoxide (CO)-labeled hemoglobin (CO-Hb) dilution method (CO method) at 6 and 24 hr after ICU admission.Results: Systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) decreased with time. Systemic oxygen delivery index (DO2I) and systemic oxygen consumption index (VO2I) showed a gradual increase during the study period. By contrast, pHi decreased to the lowest value (7.26±0.05) at six hours and returned to normal levels (7.34±0.04) at 24 hr after ICU admission. Changes in BVc between six and 24 hr ranged from −242 ml to 978 ml (mean, 334±338 ml). The pHi increased in patients whose BVc increased by >300 ml. Mean fluid balance was negative in this period (−386±667 ml; range, −1786− + 423 ml).Conclusion: The pHi showed the lowest value at six hours and returned to normal at 24 hr after ICU admission. The pHi increased with the decrease in vascular resistance and with the increases in BVc in this period. The improvement of pHi, an indicator of splanchnic perfusion, appears to be related to systemic vasodilatation and an increase in BVc.RésuméObjectif: Déterminer les changements de pH gastrique intramuqueux (pHi) qui suivent un pontage aortocoronarien, comparés aux variables hémodynamiques générales et au volume sanguin circulant (VSc).Méthode: Vingt patients qui ont subi un pontage aortocoronarien sous circulation extracorporelle (CEC) légèrement hypothermique ont participé à l’étude. Les variables hémodynamiques et le pHi ont été mesurés à 3, 6, 12 et 24 h après l’admission à l’unité des soins intensifs (USI). La mesure du pHi a été faite avec un cathéter gastrique tonométrique. Le VSc a été mesuré par la méthode de dilution de l’hémoglobine marquée à l’oxyde de carbone (CO-Hb), à 6 et à 24 h après l’admission à l’USI.Résultats: L’indice de résistance vasculaire générale (IRVG) et l’indice de résistance vasculaire pulmonaire (IRVP) ont baissé en fonction du temps. L’indice de distribution d’oxygène générale (DO2I) et l’indice de consommation d’oxygène générale (VO2I) ont affiché une augmentation graduelle pendant l’étude. Par ailleurs, le pHi a présenté sa plus basse valeur (7,26±0,05) à six heures et est revenu à la normale (7,34±0,04) à 24 h après l’admission à l’USI. Le VSc s’est modifié entre 6 et 24 h, de −242 ml à 978 ml (moyenne, 334±338 ml). Le pHi s’est élevé chez les patients dont le VSc a augmenté de > 300 ml. Le bilan hydrique moyen a été négatif pendant cette période (−386±667 ml; limites, −1786− +423 ml).Conclusion: Le pHi le plus bas a été noté à 6 h et est revenu à la normale à 24 h après l’admission à l’USI. Le pHi a augmenté selon la baisse de résistance vasculaire et l’augmentation du VSc pendant ce temps. L’amélioration du pHi, un indicateur de perfusion splanchnique, semble relié à une vasodilatation générale et à une augmentation du VSc.

Spontaneous innominate and left common carotid artery dissection with bovine aortic arch

We describe a case of a 63-year-old woman who presented with spontaneous dissection of the innominate and left common carotid arteries arising from a common trunk, so-called “bovine aortic arch.” The entry tear was seen in the common trunk at the origin of the innominate artery with no dissection extending into the aortic arch or the ascending aorta. The dissection was resected and total arch replacement was performed considering the aortic wall fragility complicated by the dissection.

Long-Survival Case of Thymic Carcinoma With Superior Vena Cava Tumor Thrombus

Sarcomatoid carcinoma of the thymus is rare and responds poorly to treatment. Invasion of great vessels and metastasis are significant predictors for poor prognosis. Thymic tumors commonly cause superior vena cava (SVC) obstruction by extrinsic compression or invasion, but intraluminal permeation is the most uncommon cause. We report a rare, long-surviving case of sarcomatoid carcinoma with SVC syndrome developed by tumor thrombus. She underwent SVC replacement and extended thymectomy. The resection indicated intracaval extension without direct invasion of thymic tumor, histologically diagnosed as sarcomatoid carcinoma. After adjuvant chemotherapy, she continues to show no apparent recurrence for five years.