Harry L. McCarthy

Developing a blood conservation program in cardiac surgery

The beneficial effects of blood transfusions have been described and widely accepted. Multiple factors, including shortages, costs, infectious risks, immunologic risks, and the risk/benefit ratio to the patient, have made the medical community reassess the guidelines for transfusion. Cardiac surgery presents a unique subset of patients, because intervention at multiple stages in the care of these patients is possible to decrease the need for transfusion. An algorithm for a cardiac surgery program was developed and a reassessment performed. Once it was seen that no detrimental effect on patient care occurred, the program was expanded, was enhanced, and subsequently has been offered to the rest of the health care system. This program has resulted in a decrease in cost while maintaining patient outcomes. The success of the program is believed to be a result of the multidisciplinary approach taken, with a commitment from all members of the blood reduction team being the key component of this success.

Human Factors Analysis of a Near-Miss Event: Oxygen Supply Failure During Cardiopulmonary Bypass

HUMAN ERROR (HE) CAUSES up to 100,000 deaths per year in medicine in the United States. The Centers for Disease Control estimates that an equal number or more patients succumb to hospital acquired infections each year (preventable deaths, HE). Reducing preventable medical injuries is a compelling urgent goal of the healthcare industry and government alike. Cardiovascular operative care is a highly complex, teamworkdependent endeavor requiring trust, training, and clear structured communication. The authors know from other high reliability/ high complexity industries (aviation/ nuclear power) that although individuals always will make errors, teams can be flawless. Crew resource management (CRM), an example of a method to reduce error because of human factors, has made its greatest improvements through empowerment of all team members to speak up, and reducing hierarchies in favor of valuing experience/wisdom. Near-miss events should be analyzed as early warnings to teams (the entire cardiac industry) so that they reduce the possibility that an individual error will go unchecked. Human Factors Analysis and Classification System (HFACs, Fig 1) was developed for use by the U.S. Navy/ Marine Corps to investigate and reduce aircraft accidents. HFACS identifies latent HE. It has been used in civil aviation, aviation maintenance, air traffic control, railroad and marine safety, and medicine. HFACS has yet to be applied systematically to cardiac surgery but will be through the following program/s.

A Comparison of a New Ultrasound-Based Whole Blood Viscoelastic Test (SEER Sonorheometry) Versus Thromboelastography in Cardiac Surgery.

BACKGROUND:Viscoelastic thromboelastography tests such as TEG™ are now routine for assessing the coagulation status of cardiac surgery patients. We compared TEG™ with a new technology, sonic estimation of elasticity via resonance (SEER) sonorheometry, to compare measures of coagulation dynamics of whole blood and assess its potential for rapid, near-point-of-care monitoring of hemostasis during cardiac surgery. METHODS:Whole blood coagulation assessment of a prospective cohort of 50 cardiac surgery patients was performed using SEER sonorheometry and blood samples collected at 4 time points during cardiac surgery: baseline before anesthetic induction, during cardiopulmonary bypass on rewarming, 10 minutes after heparin reversal by protamine, and on patient transfer to the intensive care unit. Clot strength trajectories (G, measured by TEG™; and clot stiffness measured by SEER sonorheometry) and clot times were assessed by repeated-measures mixed models. Strength of association between the 2 methods (clot stiffness and clot times) was assessed using a modified Bland-Altman method for repeated measures; Deming (orthogonal) regression was used to quantify method concordance (constant and proportional bias). RESULTS:Clot strength/stiffness and clot time measures for both techniques showed similar tracking of trajectories. Strength of association between methods was acceptable (correlations, 0.8–0.9); however, Deming regression detected substantial deviation (bias) between techniques. SEER clot stiffness values averaged approximately 10 hPa higher than corresponding G at all time points. Reaction time (TEG™) was 1 to 2.5 minutes longer than corresponding clot times (SEER). Laboratory times (from sample drop-off to results) were substantially less for SEER sonorheometry (median time, 11–17 minutes) compared with nonautomated kaolin TEG™ (median time, 42 minutes). CONCLUSIONS:Currently, no viscoelastic hemostatic analyzer system can be considered the “gold standard”; therefore, differences observed between TEG™ and SEER are of importance only because they show that the methods are not perfectly substitutable. Measurements of clot stiffness determined by the 2 methods were correlated but not interchangeable. Reasons for discrepancies include the substantial difference in the physical methods of inducing coagulation activation in samples and the mathematical assumptions underlying calculations of G. Future studies will be required to evaluate SEER sonorheometry’s abilities to identify bleeding diatheses (sensitivity/specificity) or to develop treatment algorithms based on the new tests.

Transapical Arterial Cannulation for Salvage Cardiopulmonary Bypass in Transcatheter Aortic Valve Replacement

Hemodynamic instability during transcatheter aortic valve replacement procedures may require transient cardiopulmonary bypass for support. In patients with severe atherosclerosis, peripheral cannulation may not be possible. This method of direct left ventricle cannulation during transapical TAVR is a facile means to provide arterial inflow.