Prothrombin Time and Activated Partial Thromboplastin Time Testing: A Comparative Effectiveness Study in a Million-Patient Sample.

BACKGROUND: A substantial fraction of all American healthcare expenditures are potentially wasted, and practices that are not evidence-based could contribute to such waste. We sought to characterize whether Prothrombin Time (PT) and activated Partial Thromboplastin Time (aPTT) tests of preoperative patients are used in a way unsupported by evidence and potentially wasteful. METHODS AND FINDINGS: We evaluated prospectively-collected patient data from 19 major teaching hospitals and 8 hospital-affiliated surgical centers in 7 states (Delaware, Florida, Maryland, Massachusetts, New Jersey, New York, Pennsylvania) and the District of Columbia. A total of 1,053,472 consecutive patients represented every patient admitted for elective surgery from 2009 to 2012 at all 27 settings. A subset of 682,049 patients (64.7%) had one or both tests done and history and physical (H&P) records available for analysis. Unnecessary tests for bleeding risk were defined as: PT tests done on patients with no history of abnormal bleeding, warfarin therapy, vitamin K-dependent clotting factor deficiency, or liver disease; or aPTT tests done on patients with no history of heparin treatment, hemophilia, lupus anticoagulant antibodies, or von Willebrand disease. We assessed the proportion of patients who received PT or aPTT tests who lacked evidence-based reasons for testing. CONCLUSIONS: This study sought to bring the availability of big data together with applied comparative effectiveness research. Among preoperative patients, 26.2% received PT tests, and 94.3% of tests were unnecessary, given the absence of findings on H&P. Similarly, 23.3% of preoperative patients received aPTT tests, of which 99.9% were unnecessary. Among patients with no H&P findings suggestive of bleeding risk, 6.6% of PT tests and 7.1% of aPTT tests were either a false positive or a true positive (i.e. indicative of a previously-undiagnosed potential bleeding risk). Both PT and aPTT, designed as diagnostic tests, are apparently used as screening tests. Use of unnecessary screening tests raises concerns for the costs of such testing and the consequences of false positive results.

Cardiovascular pharmacotherapeutic considerations in patients undergoing anesthesia.

Demographic shifts toward an increasingly older population have resulted in a high prevalence of persons taking cardiovascular medication. Many patients on cardiovascular medications will require surgical intervention for conditions often unrelated to their cardiovascular pathology. Cardiologists and anesthesiologists alike must be knowledgeable about the potential interactions between cardiovascular drugs and anesthetics agents or adjuvant therapies administered perioperatively. Current recommendations suggest that beta blockers, calcium channel blockers, amiodarone, and alpha2 agonists should be continued throughout the perioperative period, whereas angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and diuretics should be discontinued on the morning of surgery and resumed in the immediate postoperative period, unless contraindicated.

The influence of physical and social contexts of eating on lunch-time food intake among southern Ontario, Canada, middle school students.

BACKGROUND: Among students, little is known about the physical and social context of eating lunch. The objective of this study was to determine if food intake (including the type of food and beverages and portion sizes) was associated with specific aspects of the physical and social lunch environment (location, with whom lunch was consumed, who prepared the food, and where the food was originally purchased). METHODS: A total of 1236 participants (males = 659, females = 566) in grades 6 (n = 359), 7 (n = 409), and 8 (n = 463) from southern Ontario, Canada, completed the Food Behavior Questionnaire during the 2005-2006 academic year. RESULTS: A total of 8159 foods and 2200 beverages were consumed during the lunch meal, which contributed to 552 kcal (SD = 429) or 30% (SD = 16) of total daily energy intake (kcal/day). Higher amounts of energy, meats and alternatives, other foods, fried foods, and pizza were consumed when participants ate in between places or at a restaurant/fast food outlet (compared with at home or school, p < 0.05) and/or when prepared by friends or others (compared with themselves or family members, p < 0.05). A large number of participants (46%) reported consuming sugar-sweetened beverages during lunch, despite a school board-level policy restricting the sales of "junk food," which appears to be brought from home. CONCLUSIONS: Our findings support schools in policy efforts that restrict fast food access (by leaving school grounds, preventing fast food companies from coming onto school grounds, or restricting sugar-sweetened beverage sales in vending machines) and that eating in between places should be discouraged.

Perioperative management of a patient with hereditary angioedema during off-pump coronary artery bypass graft surgery.

The case of a patient with hereditary angioedema (HAE), a rare, life-threatening disorder caused by reduced activity of the C1 esterase inhibitor, and requiring off-pump coronary artery bypass graft (OP-CABG) surgery, is presented. Perioperative management of patients with HAE who undergo complex cardiac surgical procedures are discussed, including an OP-CABG surgical approach to decrease complement activation, fresh-frozen plasma administration to increase C1 esterase inhibitor activity, and administration of reduced doses of heparin and protamine to minimize heparin-protamine complex formation.

Right ventricular systolic function is not depressed in morbid obesity.

BACKGROUND: The increased pulmonary blood volume associated with the increased total blood volume in morbidly obese patients increases pulmonary artery pressure and pulmonary vascular resistance, resulting in increased right ventricular (RV) afterload. Thus, the morbidly obese may develop RV dysfunction owing to the increased RV afterload. We examined this possibility by assessing RV contractile function in morbidly obese patients, using RV end-systolic pressure-volume relationship and RV systolic time intervals. METHODS: Included were 25 morbidly obese patients undergoing gastric bypass surgery under general anesthesia. Pulmonary artery pressure and RV end-systolic volume were measured with a thermodilution pulmonary artery catheter. Pulmonary arterial dicrotic notch pressure was used as an estimate of RV end-systolic pressure. Two data points were used to define RV end-systolic pressure-volume relationship. RV systolic time intervals were determined by simultaneous graphic display of the electrocardiograph, phonocardiograph, and pulmonary artery pressure curve, and were expressed as a pre-ejection period/RV ejection time ratio. RESULTS: The mean slope of right ventricular end-systolic pressure-volume relationship line was 0.54 +/- 0.13 and mean pulmonary vascular resistance 274 +/- 80 dyne.sec.cm(-5).m(-2). The mean pre-ejection period/RV ejection time ratio was 0.4 +/- 0.11. There was an inverse correlation between the pre-ejection/RV ejection time ratio and the slope of RV end-systolic pressure-volume relationship line (R(2)=0.658, P<0.0001). CONCLUSION: Our data indicate that RV function is not depressed in morbid obesity despite increased RV afterload.

General anesthesia for ophthalmic surgery.

Skillful anesthetic management is integral to optimal outcomes after ophthalmic surgery. Although the majority of ophthalmic operations in the United States are performed with local anesthetic techniques, nonetheless general anesthesia may be either necessary or advisable in several challenging circumstances. Ophthalmic patients are often at the extremes of age, and not uncommonly have extensive associated systemic or metabolic diseases. Because the complications of ophthalmic anesthesia can be vision threatening or life threatening, it is imperative that the ophthalmologist and the anesthesiologist understand the complex and dynamic interaction among patient diseases, anesthetic agents, ophthalmic drugs, and surgical manipulation. Effective communication and planning among all involved are essential to safe and efficient perioperative care.