Biomedical subjects

S Takamoto

Publications and source records attributed to S Takamoto.

At least 73 records · Page 4Linked to original sources

PubMed2000

Predictive risk factors for delayed extubation in patients undergoing coronary artery bypass grafting.

Prolonged mechanical ventilation increases hospitalization costs, airway and lung trauma, and stress. The objective of this study was to elucidate patient characteristics and operative variables that predict delayed extubation in patients undergoing coronary artery bypass grafting (CABG). The records of 167 patients who underwent CABG between 1994 and 1998 were examined retrospectively. The patients were divided into early and delayed extubation groups. Putative factors affecting the duration of intubation were included in a univariate analysis using the t-test and chi-squared test. A logistic regression model was then developed to determine the factors associated with delayed extubation. Forty-four percent of the patients needed prolonged mechanical ventilation (more than 24h). Univariate predictors of delayed extubation (P < 0.05) were emergency surgery, preoperative use of an intra-aortic balloon pump (IABP), the duration of anesthesia, surgery, cardiopulmonary bypass and aortic cross-clamping, the total volume of fentanyl. lowest rectal temperature, glucose level, perioperative transfusion, bleeding, perioperative heart failure, perioperative insertion of IABP, postoperative transfusion, cardiac index, inspired oxygen fraction (FiO2), arterial oxygen tension (PaO2), the PaO2/FiO2 ratio, and the volume of catecholamine. In the delayed extubation group, the intensive care unit stay was significantly longer (P < 0.001) and re-exploration was required more frequently (P = 0.004). Excellent prediction was provided by a model consisting of six variables: age, duration of surgery, perioperative heart failure, glucose level, postoperative transfusion, and the PaO2/FiO2 ratio. These results suggest that decreasing the cardiopulmonary bypass time, maintaining a low glucose level during cardiopulmonary bypass, and ensuring adequate perioperative hemostasis may help to avoid pulmonary dysfunction and delayed extubation. Moreover, the PaO2/FiO2 ratio may be a useful predictor of delayed extubation in patients undergoing CABG.

Aged↗

PubMed2000

Strategies for CABG patients with carotid artery disease and perioperative neurological complications.

Postoperative neurological complications not only increase morbidity and mortality, but also prolong hospital stay and elevate hospital costs. From 1995, carotid artery duplex scanning (CADS) has been performed in our hospital as screening for cerebrovascular disease in patients undergoing nonemergency coronary artery bypass grafting (CABG). This study was designed to evaluate the usefulness of our strategy for preventing stroke during CABG. Between 1995 and 1997, 179 patients underwent isolated CABG. Of the nonemergency CABG patients, 146 underwent preoperative CADS. Three patients underwent a combined carotid endoarterectomy (CEA)/CABG procedure. One hundred and thirteen patients were men (77.3%), and the median age was 64, with a range of 39-82 years. The mean graft number was 2.7 +/- 0.9. Previous neurological events had occurred in 12 patients. Forty-five patients (30.8%) had abnormal CADS findings. Two (1.4%) of these patients had carotid stenosis > or = 90% in area, and five had total occlusion of the carotid artery. When the risk factors were evaluated, age and previous cerebrovascular disease (CVD) were found to be significantly higher in the group with abnormal CADS findings (P = 0.0012 and P = 0.0312). On multivariate analysis, the predictor of abnormal CADS findings were age and previous CVD (P < 0.01 and P < 0.05). Six patients (3.3%) developed postoperative stroke due to emboli (five cases) or perioperative hypoperfusion (one case). Three patients who underwent the combined CEA/CABG procedure did not suffer from any neurological complications. Preoperative screening by CADS is helpful for evaluating the presence of carotid artery disease in patients undergoing CABG. Further investigations to clarify the carotid hemodynamics are important, and synthetic assessment will be required to determine the most appropriate operative strategy.

Adult↗

PubMed2000

Right heart bypass for left circumflex coronary artery bypass grafting.

Displacement of the heart to expose the left circumflex artery (LCX) causes hemodynamic disturbance during off-pump coronary artery bypass grafting (CABG). We applied right heart bypass (RHB) using a heparin-coated centrifugal pump without an oxygenator in an attempt to stabilize the hemodynamics. Five mongrel dogs (15.5-20 kg) were used. Hemodynamic parameters were continuously monitored at a fixed rate of 80 beats/min. The LCX was exposed with the use of an Octopus Tissue Stabilizer. After baseline data were obtained, each dog was placed in the Trendelenburg position. Finally, RHB was established with different pump flows. LCX exposure caused a significant decrease in aortic flow (to 33.1% +/- 13.1% of the baseline value) and arterial mean pressure (to 68.3% +/- 8.5%) (P < 0.001). Trendelenburg positioning caused these values to recover to 57.1% +/- 6.7% and 72.5% +/- 7.7%, respectively. RHB with 50% flow significantly improved the hemodynamic values, although 100% flow significantly increased LAP by 134.8% +/- 19.7% (P < 0.01). Tilting of the canine heart to expose the LCX caused significant deterioration of the hemodynamic values. Trendelenburg positioning was moderately effective, and RHB very effective, in improving the hemodynamics. In a limited number of cases, an appropriate flow of RHB may provide safe hemodynamic assistance during off-pump CABG of the LCX.

Animals↗

PubMed2000

New instrumentation for video-assisted anterior spine release.

Endoscopic surgery in the area of orthopedics has been evolving, particularly in spine surgery. We describe the clinical outcome of thoracoscopic anterior spine release using new instruments. A harmonic scalpel (HS) with a 5-mm hook dissector was used to dissect the spine and rib and to coagulate and transect the vascular bundles. A rib dissector and resector were used for excision of the rib to be implanted in the disk spaces. We treated scoliosis in four patients (three male, one female) with a mean age of 19.5 +/- 4.5 years and thoracolumbar kyphosis in a 16-year-old male patient. A mean number of 6.5 +/- 2.5 vertebrae with scoliosis and four vertebrae with kyphosis were released. In all cases, division of the vascular bundle and exposure of the spine were completed using only the HS, and excision of a rib segment was performed via a port incision using only the rib dissector and resector. The mean duration of thoracoscopic anterior release was 92 +/- 28 min. Blood loss was minimal during and after surgery. Thoracoscopic anterior spine release can be facilitated by the new instruments described above.

Adolescent↗

PubMed2000

Ultrasonic coagulator for video-assisted internal mammary artery harvest.

BACKGROUND: The Harmonic Scalpel (HS; Ethicon Endo-Surgery, Cincinnati, OH, USA) is an ultrasonic coagulator that generates less heat than electrocautery. We compared canine internal mammary arteries (IMAs) harvested using the HS or electrocautery and reviewed the early clinical outcome after thoracoscopic IMA takedown with the HS. METHODS: Using HS and bipolar electrocautery (BE), 51 and 49 IMA branches, respectively, in six mongrel dogs were divided. The divided branches were subjected to a pressure tolerance test. The impact of coagulation on the main trunk was investigated microscopically. Thoracoscopic IMA harvesting with the HS was performed in 41 patients. Seven human IMA segments including 10 branches were examined microscopically. Postoperative angiography of 40 IMA grafts (97.6%) was performed. RESULTS: All the IMA branches withstood intraluminal pressures up to 250 mmHg. With BE, coagulation reached the adventitia of the main trunk in six segments (12.2%), but the HS caused no injury. Thoracoscopic IMA harvesting with excellent hemostasis was achieved using only the HS in all 41 patients. The main trunks of the human IMA segments were microscopically intact, and postoperative angiography demonstrated that the IMA grafts were intact. CONCLUSION: The HS appears to be a reliable coagulator for thoracoscopic IMA harvesting with minimal damage.

Animals↗

PubMed2000

Minimal damage during endoscopic latissimus dorsi muscle mobilization with the harmonic scalpel.

BACKGROUND: To reduce wound-related complications, a video-assisted surgical technique has been adopted for the mobilization of the latissimus dorsi muscle. We postulated that thermal damage to the muscle might be minimized by using a Harmonic Scalpel instead of electrocautery during this procedure. METHODS: Canine latissimus dorsi muscles were mobilized through a small incision, assisted by a videoscope. In 6 dogs, dissection with electrocautery was used to mobilize the latissimus dorsi muscle. In 6 other dogs, the Harmonic Scalpel was used. We compared operation times, wound infection rates, histologic changes in the muscles, and ease of handling between these groups. RESULTS: The operation time was significantly shorter in the Harmonic Scalpel group than in the electrocautery group (61.5 versus 106.5 minutes, p = 0.00014). The Harmonic Scalpel caused less histologic damage to the mobilized muscles and produced less vision-obscuring smoke. CONCLUSIONS: The Harmonic Scalpel shortens the operation, minimizes muscle damage, and facilitates the performance of video-assisted latissimus dorsi muscle mobilization.

Animals↗

PubMed2000

Aortobronchial fistula late after transverse arch replacement.

We report an unusual case of aortobronchial fistula late after transverse arch replacement caused by the remnant of a temporary bypass near the ascending aorta. In reconstructive surgery of the ascending aorta, antegrade perfusion is preferably performed through a side branch after completion of the distal anastomosis by some surgeons. This report suggests possible risk of a serious late complication unless the side branch is placed and tailored properly.

Aged↗

PubMed2000

Three-dimensional computed tomography for reoperative minimally invasive coronary artery bypass.

We have been using three-dimensional computed tomography (3-D CT) in reoperative coronary artery bypass grafting performed by using a minimally invasive approach. Preoperative 3-D CT scanning can provide beneficial anatomical information about old patent grafts as well as the internal thoracic artery. Thus a mini-thoracotomy can be created at an optimal site, leaving the old graft untouched, and the length of the harvested internal thoracic artery, necessary for the bypass, can be assessed using this new modality.

Coronary Artery Bypass↗

PubMed2000

Minimally invasive limited pericardiectomy: the hybrid approach.

This communication describes our clinical experience with the hybrid method, a video-assisted anterior minithoracotomy approach developed for minimally invasive limited pericardiectomy to treat 8 patients with massive pericardial effusion. The average operating time was 37.2 minutes, and there was no procedure-related morbidity or mortality. The mean follow-up period was 5.6 months, and there have been no recurrences. The hybrid approach can be accomplished irrespective of pleural adhesions. It eliminates the need for hemipulmonary collapse, making it more advantageous than the totally port-access thoracoscopic approach.

Aged↗

PubMed2000

Myocardial tactile stiffness during acute reduction of coronary blood flow.

BACKGROUND: Evaluation of regional myocardial contractile function is of clinical importance. We have developed a new tactile sensor system for accurate measurement of myocardial stiffness in situ. We found that the myocardial stiffness measured by this sensor, which we call tactile stiffness, can be a very useful index for accurate quantification of regional myocardial function. In this study, we used a coronary stenosis model to investigate regional myocardial tactile stiffness under conditions of reduced coronary blood flow. METHODS: The myocardial tactile stiffness, coronary blood flow, and ventricular pressure and volume, of five open chest mongrel dogs weighing 15 to 17 kg, were measured. After measuring the baseline myocardial stiffness, coronary arterial stenosis was induced with a balloon occluder. RESULTS: Reducing the coronary flow to 50% and 25% of the baseline level reduced the end-systolic tactile stiffness significantly from 2.20+/-0.16 g/mm2 to 2.05+/-0.20 g/mm2 (p<0.05) and from 2.21+/-0.16 g/mm2 to 1.96+/-0.18 g/mm2 (p<0.01), respectively. Reducing the flow, to 50% and 25%, increased the end-diastolic stiffness significantly from 1.29+/-0.15 g/mm2 to 1.39+/-0.14 g/mm2 (p<0.01) and from 1.30+/-0.16 g/mm2 to 1.46+/-0.14 g/mm2 (p<0.05), respectively. CONCLUSIONS: We consider that the regional myocardial tactile stiffness will be a useful index sensitive enough to detect changes in regional contractile function under conditions of reduced coronary blood flow.

Acoustics↗

PubMed2000

Systemic-to-pulmonary shunt in a patient with isolation of the subclavian artery.

A surgical procedure is described that was carried out to treat an 18-month-old boy with tetralogy of Fallot, right aortic arch, and isolation of the left subclavian artery. The patient underwent a descending aorta-right pulmonary artery shunt using a polytetrafluoroethylene graft, as a systemic-pulmonary shunt. The effectiveness of this procedure in patients with some special conditions is discussed.

Abnormalities, Multiple↗

PubMed2000