Coronary artery bypass surgery in women.

Coronary artery disease remains a predominant cause of morbidity and mortality in women. Some studies indicate that there exists a degree of gender bias in the distribution of surgical therapy for coronary artery disease. Numerous studies have demonstrated that female patients have a higher operative mortality rate when undergoing coronary artery bypass surgery. The reasons for this appear to be many including an increased number of comorbid factors in female patients, instability at the time of surgery, and smaller coronary artery size resulting in more technical difficulties and greater risk of incomplete revascularization. Once past the perioperative time period, however, female patients have survival and functional benefits from surgery equivalent to those of men. Increased awareness of clinical manifestations of coronary artery disease in women and careful selection of patients for surgical therapy is warranted.

Intravenacaval membrane oxygenation and carbon dioxide removal in severe acute respiratory failure.

STUDY OBJECTIVE: To characterize the physiologic response to, and safety of, intravenacaval membrane oxygenation and carbon dioxide removal. DESIGN: Interventional before-after study. SETTING: University teaching hospital ICU. PATIENTS: Twenty-two patients with severe acute respiratory distress syndrome (ARDS). INTERVENTIONS: Implantation of a hollow-fiber membrane oxygenator (IVOX; CardioPulmonics; Salt Lake City, Utah) into the superior and inferior venae cavae by venotomy of the right femoral or right internal jugular vein for a duration of up to 20 days. MEASUREMENTS: Hemodynamic measurements using pulmonary artery and systemic artery catheters, ventilator settings (FIO2, minute ventilation, peak inspiratory pressure, and positive end-expiratory pressure), arterial and mixed venous blood gases (pH, PCO2, PO2, and measured saturation), and clinical laboratory determinations (CBC, fibrinogen, plasma hemoglobin, complement C3 and C5) were obtained. Calculations of PaO2/FIO2 ratio and PaCO2-VE product were used to assess gas exchange efficacy. Microbiologic cultures were obtained from the device and wound following explantation. Survival to ICU discharge and hospital discharge were recorded. RESULTS: Implantation was successful in 20 of 22 patients. Gas exchange rates averaged 50.4 +/- 15.8 mL.min-1 for carbon dioxide and 71.1 +/- 20.2 mL.min-1 for oxygen. A reduction in FIO2 from 0.78 +/- 0.16 to 0.63 +/- 0.21 and in VE from 177 +/- 94 mL.kg-1.min-1 to 127 +/- 58 mL.kg-1.min-1 was possible within 4 h post-implantation. By 12 h, FIO2 was reduced to 0.57 +/- 0.18. Indices of gas exchange improved significantly after implantation, with PaO2/FIO2 ratio increasing from 79 +/- 20 to 112 +/- 47 and PaCO2-VE product decreasing from 7.6 +/- 4.2 to 4.9 +/- 2.5 within 4 h. A significant reduction in peak inspiratory pressure was achieved (45 +/- 10 to 38 +/- 9 cm H2O). Major complications were blood loss during implantation requiring transfusion in 11 patients, a retroperitoneal bleed in 1 patient, and femoral deep venous thrombosis in 4 patients, but there were no long-term sequelae or IVOX-related deaths. The ICU and hospital survival were 10/20 (50%) and 8/20 (40%), respectively. CONCLUSIONS: Intravenacaval membrane oxygen and carbon dioxide removal can provide partial respiratory support during severe respiratory failure and permit reductions in the level of mechanical ventilator support, with an acceptable safety profile.

Current trends and considerations in the surgical treatment of coronary artery disease.

Management of coronary artery disease has changed greatly in the past three decades. Surgical treatment has improved, especially with the introduction of bypass conduits, like the internal mammary artery, which possess a patency rate far superior to that of the saphenous vein. Use of this arterial graft has so encouraged surgeons that other autologous arterial grafts are being tried. Grafts from nonautologous sources are being investigated, but none have yet been found to approach the excellent performance of the internal mammary artery. While the surgical treatment for myocardial ischemia has greatly improved, characteristics of the patient population have not. Patients presently sent for surgery are older, in worse general health, and have poorer cardiac function and coronary disease than their counterparts of several decades ago. Nevertheless, expansion of surgical options, including cardiac transplantation has allowed even the highest risk patients to be considered for surgical intervention.

In vivo gas transfer performance of the intravascular oxygenator in acute respiratory failure.

The intravascular oxygenator (IVOX) has undergone both animal and clinical trials. Data from the animal studies have demonstrated that the device is capable of transferring up to approximately 100 ml/min of oxygen and carbon dioxide. Initial data from the human trials suggest that gas transfer, although approaching these levels, varied widely in patients with respiratory failure. We studied the factors affecting gas exchange in 26 patients with severe acute respiratory failure who underwent intravenacaval support of gas exchange with IVOX. The patients underwent monitoring of IVOX gas transfer rates, hemodynamics, blood gases, and ventilation parameters at scheduled intervals following device insertion. All devices functioned following implantation. The mean value for O2 transfer was 64 +/- 21 SD ml/min (range 15-114 ml/min) and for CO2 transfer was 48 +/- 17 ml.min-1 (range 14-112 ml/min). CO2 transfer correlated positively with device surface area, cardiac output, and mixed venous Pco2 and negatively with duration of implantation. O2 transfer did not correlate with any patient factors probably due to error inherent in the measurement of this variable. Independent measurements of IVOX gas transfer by respiratory gas exchange in a subset of patients with normal values of mixed venous Pco2 were in good agreement with the routine measurements and indicated that the device provided up to 26% of gas exchange requirements in this subset. We conclude that IVOX transfers clinically useful amounts of oxygen and carbon dioxide in vivo. Factors that influence gas transfer include device surface area, PvCO2, cardiac output, and duration of implantation. Optimization of these factors (such as with permissive hypercapnea) could result in enhanced performance in vivo.

Prolonged intracorporeal support of gas exchange with an intravenacaval oxygenator.

Patients with severe respiratory failure undergoing conventional mechanical ventilation typically are exposed to levels of ventilator support that place the patient at risk of barotrauma or oxygen toxicity. In severe cases, gas exchange may be inadequate despite maximal ventilator support. We report two cases of advanced respiratory failure in which augmentation of gas exchange was provided for prolonged periods (18 and 13 days) with an intravenacaval hollow-fiber membrane oxygenator (IVOX). Following implantation, significant reductions in ventilator support were possible with improvement in arterial blood gas values. No significant complications were noted. IVOX can provide clinically useful augmentation of gas exchange in respiratory failure and can be used for prolonged periods.

Group F streptococcal empyema from aspiration of a grass inflorescence.

A previously healthy 15-year-old boy was seen with a loculated right lower lobe empyema. Group F beta-hemolytic streptococci were cultured from the pleural fluid. Surgical intervention was required. An unsuspected aspirated grass inflorescence and a bronchopleural fistula were discovered during a decortication procedure.