Shubjeet Kaur

Reduction of bleeding after heart operations through the prophylactic use of epsilon-aminocaproic acid

UNLABELLED Excessive postoperative bleeding after heart operations continues to be a source of morbidity. This prospective double-blind study evaluated epsilon-aminocaproic acid as an agent to reduce postoperative bleeding and investigated its mode of action. One hundred three patients were randomly assigned to receive either 30 gm epsilon-aminocaproic acid (51 patients) or an equivalent volume of placebo (52 patients). In a subset of these patients (14 epsilon-aminocaproic acid, 12 placebo), tests of platelet function and fibrinolysis were performed. RESULTS By multivariate analysis, three factors were associated with decreased blood loss in the first 24 hours after operation: epsilon-aminocaproic acid versus placebo (647 ml versus 839 ml, p = 0.004), surgeon 1 versus all other surgeons (582 ml versus 978 ml, p = 0.002), and no intraaortic balloon versus intraaortic balloon pump use (664 ml versus 1410 ml, p = 0.02). No significant differences in platelet function could be demonstrated between the two groups. Inhibited fibrinolysis, as reflected by less depression of the euglobulin clot lysis and no rise in D-dimer levels, was significant in the epsilon-aminocaproic acid group compared with the placebo group. CONCLUSION The intraoperative use of epsilon-aminocaproic acid reduces postoperative cardiac surgical bleeding.

Investigation of noninvasive in vivo blood hematocrit measurement using NIR reflectance spectroscopy and partial least-squares regression

Hematocrit (Hct), the volume percent of red cells in blood, is monitored routinely for blood donors, surgical patients, and trauma victims and requires blood to be removed from the patient. An accurate, noninvasive method for directly measuring hematocrit on patients is desired for these applications. The feasibility of noninvasive hematocrit measurement by using near-infrared (NIR) spectroscopy and partial least-squares (PLS) techniques was investigated, and methods of in vivo calibration were examined. Twenty Caucasian patients undergoing cardiac surgery on cardiopulmonary bypass were randomly selected to form two study groups. A fiber-optic probe was attached to the patients forearm, and NIR spectra were continuously collected during surgery. Blood samples were simultaneously collected and reference Hct measurements were made with the spun capillary method. PLS multivariate calibration techniques were applied to investigate the relationship between spectral and Hct changes. Single patient calibration models were developed with good cross-validated estimation of accuracy (∼ 1 Hct%) and trending capability for most patients. Time-dependent system drift, patient temperature, and venous oxygen saturation were not correlated with the hematocrit measurements. Multi-subject models were developed for prediction of independent subjects. These models demonstrated a significant patient-specific offset that was shown to be partially related to spectrometer drift. The remaining offset is attributed to the large spectral variability of patient tissue, and a significantly larger set of patients would be required to adequately model this variability. After the removal of the offset, the cross-validated estimation of accuracy is 2 Hct%.

Catheter-Related Infection

Intravascular catheters are an inherent part of medical practice and may be inserted for a wide variety of indications from the basic (administration of medications or fluids) to the complex (e.g., hemodynamic monitoring of critically ill patients). One significant risk associated with the use of these catheters is infection. The infection may be local (suppuration at the site of insertion), thereby resulting in patient discomfort and the inconvenience of changing the site, or systemic, resulting in bacteremia, osteomyelitis, or endocarditis. The annual incidence of catheter-related bloodstream infections (CRBSI) caused by central venous catheters in the intensive care unit is approximately 80,000 (1). Contrary to earlier studies, recent data suggest that when patients are stratified according to severity of illness, the mortality due to CRBSI is not increased. However, hospital length of stay and costs (

Self‐Reported Function More Informative than Frailty Phenotype in Predicting Adverse Postoperative Course in Older Adults

3,700 –

Intraoperative echocardiographic images of right ventricular outflow tract sarcoma.

34,000 per episode) associated with treating the bacteremia are substantially increased (1,2). This chapter focuses on the pathogenesis, prevention, and treatment of catheter-related infections.

Development of an in-vivo PLS calibration model for the noninvasive measurement of blood, hematocrit using NIR spectroscopy

Current preoperative assessment tools such as the American College of Surgeons Surgical Risk Calculator (ACS Calculator) are suboptimal for evaluating older adults. The objective was to evaluate and compare the performance of the ACS Calculator for predicting risk of serious postoperative complications with the addition of self‐reported physical function versus a frailty score.

Improved myocardial protection in minimally invasive aortic valve surgery with the assistance of port-access technology

relatively new treatment. In recent years, TAVI procedures have become a valid option in high-risk patients who are not candidates for surgical valve replacement. TAVI can be applied via the transapical, transfemoral, and transaxillary approaches. While the transapical and the transaxillary approaches require general anesthesia, the transfemoral approach can be performed safely under local anesthesia. Monitored anesthetic care with local anesthesia of the groin plus sedation is suitable for the transfemoral approach. In the current study, computed tomography (CT) measurements were done in awake patients while the measurements for RT 3D TEE were done in anesthetized patients. The authors indicated this issue in the study limitations. They could carry out RT 3D TEE before surgery using regional anesthesia when the CT study was performed. Further studies are needed to reveal whether RT 3D TEE can be used as an alternative imaging technique for measuring the coronary ostia distances from the aortic annulus in patients undergoing TAVI.

APPLICATION OF NEAR INFRARED SPECTROSCOPY FOR THE NONINVASIVE MEASUREMENT OF HEMATOCRIT ON SURGICAL PATIENTS

Near infrared spectra and hematocrit reference measurements were collected from 37 cardiac and vascular surgery patients and calibration models developed using partial least squares analysis. Factors which influence the development of accurate models are discussed.