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W J Ko

Publications and source records attributed to W J Ko.

At least 73 records · Page 4Linked to original sources
PubMed1999

Unpreconditioned free revascularized dynamic cardiomyoplasty. Is it feasible?

BACKGROUND: Cardiomyoplasty is a new ventricular bioassist device for myocardial failure. But there are some limitations in standard cardiomyoplasty, such as the orientation of the muscle and fiber and the efficiency of the contractile segment of the flap. Free revascularized latissimus dorsi flap may be a good idea for solving these problems. METHODS: We designed a canine free latissimus dorsi flap by revascularizing the flap with the left internal thoracic vessels by micro-surgical technique. Group I (n = 3) as control was performed by standard cardiomyoplasty, and the Group II (n = 10) was performed by the revascularized method. The heart was then wrapped by the revacularized flap. Group II was divided into IIa (n = 6, no pre-treatment before revascularization) and IIb (n = 4, normal saline pre-treatment before revascularization) by the different preservation methods. Hemodynamic data were recorded. RESULTS: Group I all survived the 8-week training period. But Group II, Group IIa and IIb, all died in 3 days, but survived more than 12 hours. The hemodynamic analysis in Group I did not show any significant change except left ventricular end diastolic pressure. It showed elevated left ventricular pressure when the cardiostimulator was ON. CONCLUSIONS: According to the result of this experiment, it seemed impossible to get a satisfactory result of more than 3 days for free revascularized cardiomyoplasty at present. There were a lot of problems waiting to be solved, such as preservation method during ischemia, bulky mass of the flap, and the potential problem of neuromuscular atrophy.

Anastomosis, Surgical↗
PubMed1999

Cardiorespiratory response of heart transplantation recipients to exercise in the early postoperative period.

In this study, we evaluated the cardiorespiratory function of orthotopic heart transplantation (OHT) recipients during exercise. Seventeen male OHT recipients, ranging in age from 22 to 60 years, participated in this study 47 +/- 21 days after surgery. The control group consisted of 17 sedentary healthy men. Breath-by-breath measurement of cardiorespiratory function was obtained during the incremental exercise of leg cycling. At peak exercise, the oxygen (O2) uptake (16.5 +/- 3.3 vs 33.9 +/- 8.2 mL.kg-1.min-1), work rate (82 +/- 19 vs 169 +/- 42 watts), heart rate (HR), O2 pulse, and blood lactate level of the OHT recipients were significantly lower than the respective values of the control group. At the ventilatory threshold, the OHT group also showed a significantly lower O2 uptake (10.7 +/- 1.6 vs 18.3 +/- 5.1 mL.kg-1.min-1), work rate (39 +/- 12 vs 89 +/- 33 watts), HR, O2 pulse, ventilatory equivalent for O2, and ventilatory equivalent for carbon dioxide. The OHT recipients showed a high resting HR (97 +/- 7 beats/min) and a low peak HR (123 +/- 14 beats/min) during exercise, and their HR continued to increase for 1 to 3 minutes after cessation of exercise. Our data revealed a low level of cardiorespiratory endurance in OHT recipients during the early postoperative stage. A multidisciplinary cardiac rehabilitation program should be considered to enhance physical functional capacity and quality of life, and promote return to work.

Adult↗
PubMed1999

Postoperative short-term sedation with propofol in cardiac surgery.

We conducted a randomized double-blind study to assess the safety and effectiveness of short-term sedation with propofol in adult patients immediately after cardiac surgery. Sixty hemodynamically stable adult patients who underwent cardiac surgery were randomly assigned to receive propofol postoperatively or no postoperative sedation. The propofol group (n = 30) received propofol infusion (1 mg.kg-1.hr-1) immediately after they awoke postoperatively. The infusion rates were adjusted to maintain a sedation level (Ramsay score) of 3. Nurses assessed the effectiveness of the sedation according to Ramsay scores; the patients also subjectively evaluated sedation. Postoperative pulmonary oxygenation dysfunction (PaO2/FiO2 < 300 mm Hg) was noted in 10 patients receiving propofol and in eight patients in the control group. The dysfunction was greatly improved after overnight ventilator support, and this improvement was not affected by propofol sedation. The propofol group received an average of 13.6 +/- 5.3 hours of propofol infusion, at an average infusion rate of 0.96 +/- 0.16 mg.kg-1.hr-1. Patients receiving propofol remained well sedated (Ramsay score > or = 2) during 99.3% of the study period, while the control patients remained anxious or agitated (Ramsay score, 1) during 12% of the study period. Patients receiving propofol were successfully extubated 9 +/- 4 minutes after cessation of propofol infusion, without complications. The turnover of intensive care unit beds was not delayed by propofol sedation. Subjective evaluations (scored on an analog scale: 0 = nil, 10 = extreme) revealed that patients receiving propofol felt less pain than those in the control group (2.3 +/- 2.7 vs 4.7 +/- 3.1, p < 0.05), had better sleep quality (7.8 +/- 2.9 vs 5.1 +/- 2.9, p < 0.05), and were more satisfied with the care they received (8.3 +/- 2.2 vs 5.8 +/- 3.9, p < 0.05). These findings suggest that propofol infusion is effective for short-term sedation of cardiac surgery patients postoperatively and that an infusion rate adequate to maintain a Ramsay score of 3 may be ideal. Postoperative sedation should be considered for all cardiac surgery patients, not only those with outward signs of anxiety or agitation.

Cardiac Surgical Procedures↗
PubMed1999

Heart transplantation with marginal recipients and donors.

With improvements in surgical techniques and management of postoperative complications, heart transplantation can now be performed with donors and recipients who were previously considered unsuitable. In this study, we report the results of heart transplantation with marginal donors and recipients in our hospital. From June 1993 through June 1998, we performed 79 heart transplantations. Marginal recipients were defined as those with high pulmonary vascular resistance (> 6 Wood units), severe renal impairment (serum creatinine > 2 mg/dL and creatinine clearance < 50 mL/min), or severe hepatic dysfunction (ALT and AST > 100 IU/L or serum bilirubin > 2.5 mg/dL). Marginal donors were those with any of the following conditions: old age (> 40 years), size mismatch (donor/recipient body weight ratio < 0.8), history of chronic alcohol use, previous cardiopulmonary resuscitation and hypotension, hepatitis B or C virus positivity, coronary artery disease, high-dose dopamine (> 10 micrograms.kg-1.min-1), or prolonged allograft ischemic time (> 4 hours). Of the 79 transplantations performed, 45 (58%) involved marginal recipients or donors. The 30-day mortality rate was 5%, and the 1-year and 5-year survival rates were 87% and 83%, respectively. The survival rates did not differ significantly between cases involving marginal donors or recipients and those involving nonmarginal donors and recipients. There were 27 marginal recipients (34%), only one of whom died during surgery. Five of six recipients with severe renal impairment needed short-term hemodialysis after transplantation. Recipients with high pulmonary vascular resistance had a higher incidence of early acute rejection (5/10 vs 22/69). Thirty-three (42%) of the patients received transplants from marginal donors, four of whom died during surgery; two died of acute vascular rejection, one of allograft failure caused by prolonged ischemic time, and one of bleeding secondary to preoperative sepsis and coagulopathy. These results show that heart transplantation may be performed in marginal recipients and donors, with acceptable operative mortality.

Adolescent↗
PubMed1998

Postpartum myocardial infarction rescued with an intraaortic balloon pump and extracorporeal membrane oxygenator.

A 37-year-old woman had postpartum myocardial infarction complicated with cardiogenic shock. The infarction was attributed to diffuse coronary artery spasm caused by methylergonovine, which had been used to treat the postpartum haemorrhage due to placenta increta. The haemodynamics could not be maintained with catecholamine infusion and intraaortic balloon counterpulsation. At last, an extracorporeal membrane oxygenator was used to save her life, and the patient was successfully weaned from the machine 100 h later; she made an uneventful recovery thereafter.

Adult↗
PubMed1998

Stress-reducing effect of physician's tape-recorded support on cardiac surgical patients in the intensive care unit.

Staying in an intensive care unit (ICU) is very stressful for patients after heart surgery. Although it is a general belief that support from doctors is important to reduce patients' tension, no quantitative data are available. We investigated the stress-reducing effects of a tape-recorded message from the physician which provided information regarding the surgery and emotional support for heart surgery patients postoperatively in the ICU. Sixty patients who underwent cardiac surgery were randomly allocated to two equal groups. The patients in the experimental group listened to a tape-recorded message from their attending surgeon soon after they recovered from anesthesia, while the control group rested during the study period. The effectiveness of the tape-recorded support program was evaluated by the influence on heart rate, blood pressure, and finger skin temperature, as well as the degree of subjective pain, tension, anxiety, depression, and anger. The pain and tension levels of the patients were measured using a visual analogue scale, while the severity of anxiety, depression, and anger was evaluated using the Brief Symptom Rating Scale. Patients' evaluation of the usefulness of the program was also assessed. After listening to the physician's recorded message, the mean increase in the skin finger temperature in the experimental group was higher than in the control group (0.44 degree C vs 0.25 degree C, p = 0.0513). The experimental group had significant decreases in their mean scores of pain (-1.11 vs 0.36, p = 0.0043), tension (-2.26 vs -0.25, p = 0.0001), anxiety (-1.3 vs -0.57, p = 0.0473), and depression (-2.24 vs -0.37, p = 0.0253). The patients showed a high need for this support program (mean need score 8.4). These findings show that a physician's tape-recorded message providing information and emotional support can reduce stress in heart surgery patients in the ICU postoperatively.

Cardiac Surgical Procedures↗
PubMed1998

Extracorporeal membrane oxygenation support for single lung transplantation in a patient with primary pulmonary hypertension.

Left single lung transplantation was performed under perioperative extracorporeal membrane oxygenation (ECMO) support for a patient of primary pulmonary hypertension. Continuous ECMO in this patient for one day after the transplantation decreased the pulmonary blood flow and probably served to minimize the potential complication of reperfusion edema of the graft. During this period, the ECMO was gradually weaned so that the grafted lung could adapt itself to the gradually increased blood flow through it. The patient was extubated without difficulty 2 days alter the removal of ECMO and made a smooth recovery.

Adult↗
PubMed1998

Extracorporeal membrane oxygenation in treatment of cardiogenic shock caused by acute myocarditis.

We report a 31-year-old woman with acute myocarditis who was transferred to our hospital because of rapidly progressive cardiogenic shock unresponsive to infusion of high doses of inotropic agents and intraaortic balloon pump support. Upon arrival at our hospital, extracorporeal membrane oxygenation (ECMO) was immediately established through a right femoral venoarterial route by percutaneous cannulation; the blood flow of ECMO was maintained at around 2,100 mL/min. Shock-induced rhabdomyolysis complicated with acute renal failure occurred. During treatment with ECMO and hemodialysis, the patient gradually recovered cardiac and renal function. The patient was maintained on ECMO for 90 hours then successfully weaned from the machine without major complications. Our experience suggests that ECMO can be used for temporary mechanical circulatory support in patients with cardiogenic shock due to acute myocarditis.

Acute Disease↗
PubMed1997

Extracorporeal membrane oxygenation in the perioperative period of heart transplantation.

Mechanical circulatory support is occasionally needed in the perioperative period of heart transplantation. Between February and May 1995, three recipients of cardiac transplant at the National Taiwan University Hospital required the use of extracorporeal membrane oxygenation (ECMO) for temporary mechanical circulatory support in the perioperative period of heart transplantation. All three patients received ECMO through the percutaneous femoral veno-arterial route. The ECMO device has a heparin-bound Carmeda Bioactive surface and centrifugal pump. Patient 1 needed ECMO for treatment of a postoperative pulmonary hypertensive crisis. Patient 2 needed ECMO for early cardiac allograft failure, possibly due to ischemia. Patient 3 needed ECMO as a bridge to his first heart transplant after acute myocardial infarction complicated with cardiogenic shock, and again as a bridge to retransplantation because of acute failure of the first cardiac transplant and finally for a temporary circulatory support during rescue treatment for acute vascular rejection of the second cardiac transplant. All three patients were successfully treated with ECMO without major complications. In conclusion, ECMO provides excellent mechanical circulatory support for some situations in the perioperative period of heart transplantation.

Aged↗
PubMed1996

Extracorporeal membrane oxygenation support for postcardiotomy cardiogenic shock.

Extracorporeal membrane oxygenation (ECMO) has had promising results in life-threatening respiratory failure and postcardiotomy cardiogenic failure. From October 1994 to October 1995, 18 patients received 19 ECMOs at National Taiwan University Hospital for severe cardiogenic shock after cardiac surgery. They included patients receiving cardiac massage or repeated bolus injections of norepinephrine to maintain blood pressure (n = 10), patients who could not be weaned off cardiopulmonary bypass after several attempts despite intraaortic balloon pumping and maximal doses of catecholamine (n = 7), and patients with progressive intractable cardiogenic shock after cardiac surgery. Venoarterial ECMO was set up via femoral artery (17 or 19 Fr cannula) and vein (19 or 21 Fr) in all patients except 2 infants. No left heart drainage was performed in any of the patients. The heparin-coated circuit (with Carmeda Bio-active Surface) was used in the last 13 patients to reduce bleeding. Ten (52.6%) of the 19 cases could be smoothly weaned off ECMO, and 6 (33.3%) of the 18 patients were discharged from the hospital in good condition. Four (80%) of the 5 patients after valvular surgery and all 3 heart transplant patients could be weaned off ECMO successfully with the survival rate being 60% and 67%, respectively. Complications included leg ischemia (n = 3), bleeding (n = 4), renal failure (n = 3), and tube rupture (n = 1). The inability to wean off ECMO was caused by multiple organ failure (n = 5), sepsis (n = 2), tube rupture (n = 1), and dysfunction of the ECMO system (n = 1). The major cause of multiple organ failure was hesitation to set up ECMO. Our preliminary results confirmed the effect of ECMO in postoperative cardiogenic shock.

Adult↗