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Biomedical subjects

K Kumon

Publications and source records attributed to K Kumon.

At least 37 records · Page 2Linked to original sources
PubMed1998

[A case of central sleep-apnea syndrome accompanied by bilateral paralysis of the diaphragma after pediatric cardiac surgery].

Sleep-apnea syndrome is a serious problem in respiratory care. Considerable attention has been paid to it, because it sometimes produces severe hypoxia and hypercapnia, and can cause death. We present a case of a six-year-old girl who showed sleep-apnea syndrome. She suffered from bilateral paralysis of the diaphragm after cardiac surgery and had to be managed under mechanical ventilation for three months. When weaning was tried from mechanical ventilation, she frequently showed apnea lasting over 15 seconds at night, and she was diagnosed as having sleep apnea. She was medicated with theophylline to stimulate the so-called respiratory center. Next day she was successfully weaned from mechanical ventilation. After she had been weaned from mechanical ventilation, hypoxia, hypercapnia, and tachycardia were detected by respiratory monitor at night. The respiratory monitor enabled us to identify the clinical appearance of sleep-apnea, and theophylline may have contributed to its improvement.

Cardiac Surgical Procedures↗
PubMed1997

Effects of inhaled nitric oxide on postoperative pulmonary circulation in patients with congenital heart disease.

We studied 22 patients with residual pulmonary hypertension or symptoms of postoperative pulmonary hypertensive crisis. They received low-dose inhalation (10 ppm) of nitric oxide (NO), a selective pulmonary vasodilator, after total correction for congenital heart anomalies. Fifteen minutes of NO inhalation improved the pulmonary circulation and lessened the imbalance in the ventilation-perfusion ratio in both groups. Thus, NO inhalation is effective in the treatment of pulmonary hypertension and in the prevention of pulmonary hypertensive crises after total correction for congenital heart anomalies. All patients continued to receive NO therapeutically. The duration of such therapeutic NO inhalation was well correlated with postoperative Qp/Qs (p = 0.014) and Rp/Rs (p = 0.029).

Administration, Inhalation↗
PubMed1997

Long-term sedation with isoflurane in postoperative intensive care in cardiac surgery.

After cardiac surgery, patients often require prolonged mechanical ventilation. We studied the effectiveness and potential toxicity of isoflurane sedation in 40 patients undergoing mechanical ventilation after cardiovascular surgery. All patients who received isoflurane (0.5-1.0 minimum alveolar concentration [MAC] were well sedated by it without significant adverse effects, such as renal, hepatic, or cardiovascular dysfunction. The highest serum inorganic fluoride concentration recorded was 45 mumol/L after 98 MAC h. Patients on isoflurane recovered more rapidly and were weaned from mechanical ventilation sooner than those sedated with intravenous drugs including fentanyl/midazolam. Patients who received intravenous sedatives, but not those on isoflurane, often showed tachyphylaxis in the early stages, and some exhibited an abstinence syndrome involving nonpurposeful movements. Patients sedated with isoflurane did not show these two side effects. In conclusion, isoflurane can provide effective long-term sedation for patients after cardiovascular surgery without significant adverse effects.

Acute Kidney Injury↗
PubMed1997

Helium/oxygen breathing improves hypoxemia after cardiac surgery.

The effects of helium/oxygen (He/O2) on oxygenation (respiratory index [PaO2/FiO2] and intrapulmonary shunt [Qs/Qt]) and on lung parameters (dynamic compliance [Cdyn] and peak inspiratory pressure [PIP]) were studied in 12 patients. After cardiac surgery, they had impairment of oxygenation without physiological findings and with normal chest radiographs despite having a positive end expiratory pressure of up to 10 cm H2O. After 90 min of inhalation of He/O2, oxygenation had improved significantly; that is, PaO2/FidO2 increased significantly (from 113 to 174 mm Hg; mean values are given; p < 0.01), and there was a significant fall in Qs/Qt (from 29 to 19%; p < 0.001) together with an increase in Cdyn (from 60 ml/cm H2O to 64 ml/cm H2O; p < 0.05). These results suggest that He/O2 may have improved oxygenation by recruiting previously obstructed small airways and alveoli.

Administration, Inhalation↗
PubMed1997

Successful treatment of mediastinitis after cardiovascular surgery using electrolyzed strong acid aqueous solution.

Dilute povidone-iodine solution has been widely used as an irrigant for the treatment of mediastinitis. However, its use is not without adverse effects and often causes poor growth of granulation tissues. To avoid the problems seen with the use of povidone-iodine solution, we applied electrolyzed strong acid aqueous solution (ESAAS) to mediastinal irrigation in 4 patients (2 infants and 2 adults) who developed mediastinitis after cardiovascular surgery. According to the "open" method, the mediastinal wound was left open and irrigated with ESAAS 1 to 3 times a day until the infection was eradicated. Satisfactory growth of granulation tissues was observed in all patients treated with no evidence of adverse effects attributable to ESAAS. Delayed primary sternum closure was performed for 2 patients, and musculocutaneous transposition of rectus abdominis for 1. Our experience suggests that irrigation with ESAAS is a safe and effective method of therapy for mediastinitis.

Acids↗
PubMed1997

[Antithymocyte globulin as conditioning regimen for bone marrow transplantation].

Bone marrow transplantation was performed with a conditioning regimen including antithymocyte globulin (ATG) for 8 patients with HLA-compatible unrelated donors or HLA mismatched donor. Administration of ATG was halted due to side effects in only 1 case, but the other cases were had no adverse reaction. During administration of ATG, platelet counts did not decrease rapidly, but platelet infusion was not effective in some cases. As compared between patients with conventional allogeneic BMT, autologous BMT or peripheral blood stem cell transplantation and those with ATG administration, no obvious difference was seen between the two groups in lymphocyte counts, CD3, CD4, CD8 and CD20 positive cells. No patient with ATG saffered graft failure or acute GVHD. However, cytomegalovirus infection was observed more frequently than in patients without ATG. In hematological malignancy, relapse was more frequent than in patients without ATG.

Adolescent↗
PubMed1996

[Transesophageal echocardiography (Part 2): Basic concepts in Doppler techniques].

Cardiac Doppler techniques provide information on blood flow dynamics by applying Doppler frequency shift analysis to echo signals from moving red blood cells. Velocity and direction of blood flow can be determined and instantaneously displayed on a monitor screen. These techniques include pulsed-wave Doppler (PWD), continuous wave Doppler (CWD) and color Doppler imaging (CDI). In PWD, short bursts of ultrasound waves are emitted at a pulse-repetition frequency (PRF), and velocity and direction of blood flow can be measured at specific locations in the heart. This technique enables measurement with high spatial resolution. By its nature as a sampling system, however, PWD can not accurately measure Doppler shift frequency exceeding the Nyquist limit (PRF/2). In CWD, ultrasound pulses are continuously emitted and received by two separate transducers. Precise localization of a sampling volume is impossible in this technique, but CWD can determine higher flow velocity without ambiguity than that detected by PWD. CWD is useful to evaluate high-velocity blood flows such as those seen with valvular diseases or shunt lesions. CDI displays two-dimensional patterns of blood flow in colors, superimposed on the two-dimensional images of the heart structures. Thus, the velocity, direction and location of blood flows can be visualized in real-time. This technique facilitates detection of abnormal blood flows in the heart and major blood vessels, and it is also utilized to evaluate the severity of valvular regurgitation.

Blood Flow Velocity↗
PubMed1996

[Transesophageal echocardiography (Part 1): Basic concepts in two-dimensional imaging and M-mode].

Transesophageal echocardiography has features suitable for intraoperative use. It enables intraoperative evaluation of cardiac or thoracic aortic lesions before and after surgical intervention. It also provides real-time information on cardiac performance throughout the operation without interfering with surgical procedures. Anatomical relationship of the esophagus and the heart allows the use of high frequency ultrasound, which is advantageous to increase the resolution of echo images. An ultrasound beam emitted by a transducer is absorbed, reflected and scattered as it progresses in inhomogeneous living tissues. The reflected ultrasound waves reach the transducer, and their mechanical vibrations are converted to electronic signals. These signals are further processed by the ultrasound imaging system, and echo images are displayed on a video screen. Ultrasound imaging techniques include M-mode, two-dimensional imaging and Doppler techniques. M-mode is the most basic technique, which displays a scroll of the echo signals along a single ultrasound beam on a video screen. It has higher temporal resolution than other modes, and is therefore useful for precise timing of events and quantitative measurements of size or distance within the cardiac cycle. Two-dimensional mode produces a real-time cross-sectional view of cardiac structures, which can be easily interpreted. It is suited to visualization of anatomic structures.

Aorta, Thoracic↗
PubMed1996

[Transesophageal echocardiography (Part 3): Clinical application Part 1].

Intraoperative transesophageal echocardiography (TEE) has a wide range of applications including monitoring of left ventricular (LV) function, evaluation of natural and prosthetic valves, detection of intracardiac thrombus, mass and vegetation, assessment of surgical repair of cardiac disease, visualization of intracardiac air, positioning of an intraaortic balloon and a coronary sinus catheter, evaluation of thoracic aortic lesions, and so on. Complications are very rare with TEE, but damage of the esophagus or stomach can occur. Gentle manipulation of the TEE probe is always required. Patients should be carefully examined prior to TEE to exclude potential esophageal or gastric lesions. Monitoring of global and regional LV function is the major application of intraoperative TEE. Fractional shortening, fractional area change, and ejection fraction are widely used estimates of global LV systolic function, but these measurements may not accurately estimate overall ventricular performance when regional wall motion abnormalities (RWMAs) exist. Regional wall motion is highly sensitive to myocardial ischemia, and a decrease or cessation of regional contraction is indicative of impaired myocardial perfusion. Assessment of RWMAs is thus very useful for diagnosis of ischemia. Although RWMAs are not always caused by acute ischemia, a new onset of RWMAs, as seen during surgery, almost certainly indicates myocardial ischemia. TEE also allows evaluation of LV diastolic function by analyzing the transmittal flow velocity.

Echocardiography, Transesophageal↗
PubMed1996

[Transesophageal echocardiography (Part 4): clinical application. Part 2].

Transesophageal echocardiography (TEE) is extremely useful in evaluating native and prosthetic valves. TEE can reveal valvular lesions that may not be demonstrated by transthoracic approach. Nonetheless significant findings could be overlooked or misinterpreted even with TEE, since three-dimensional structures, motions, or flows are assessed through two-dimensional images. In addition, changes in the imaging conditions can considerably affect echo images, and thereby their interpretation. These inherent limitations of the technique must be kept in mind, and diagnosis should be based not only on echographic findings but on hemodynamic conditions and clinical observations. Other applications of intraoperative TEE include detection of intracardiac thrombi, tumors and vegetations, visualization of air bubbles, positioning of an intraaortic balloon and a coronary sinus catheter, evaluation of thoracic aortic lesions and pleural effusion, etc. In particular, TEE exhibits excellent sensitivity and specificity in diagnosing aortic dissection, and is indicated as a first-line examination when urgent evaluation is required for acute aortic dissection.

Aortic Dissection↗