BACKGROUND: Functional capacity assessment plays a core role in the preoperative evaluation. The Duke Activity Status Index (DASI) and the 6-minute walk test (6MWT) are 2 methods that have demonstrated the ability to evaluate functional capacity and predict perioperative outcomes. Smartphones offer a novel method to facilitate functional capacity assessment as they can easily administer a survey and accelerometers can track patient activity during a 6MWT. We developed a smartphone application to administer a 6MWT and DASI survey and performed a pilot study to evaluate the accuracy of a smartphone-based functional capacity tool in our Anesthesia and Perioperative Medicine Clinic. METHODS: Using the Apple ResearchKit software platform, we developed an application that administers a DASI survey and 6MWT on an iOS smartphone. The DASI was presented to the patient 1 question on the screen at a time and the application calculated the DASI score and estimated peak oxygen uptake (Vo 2). The 6MWT used the CMPedometer class from Apple’s core motion facility to retrieve accelerometer data collected from the device’s motion coprocessor to estimate steps walked. Smartphone estimated steps were compared to a research-grade pedometer using the intraclass correlation coefficient (ICC). Distance walked was directly measured during the 6MWT and we performed a multivariable linear regression with biometric variables to create a distance estimation algorithm to estimate distance walked from the number of steps recorded by the application. RESULTS: Seventy-eight patients were enrolled in the study and completed the protocol. Steps measured by the smartphone application as compared to the pedometer demonstrated moderate agreement with an ICC (95% CI) of 0.87 (0.79–0.92; P = .0001). The variables in the distance estimation algorithm included (β coefficient [slope], 95% CI) steps walked (0.43, 0.29–0.57; P < .001), stride length (0.38, 0.22–0.53; P < .001), age in years (−1.90, −3.06 to −0.75; P = .002), and body mass index (−2.59, −5.13 to −0.06; P = .045). The overall model fit was R 2 = 0.72, which indicates a moderate level of goodness of fit and explains 72% of the variation of distance walked during a 6MWT. CONCLUSIONS: Our pilot study demonstrated that a smartphone-based functional capacity assessment is feasible using the DASI and 6MWT. The DASI was easily completed by patients and the application clearly presented the results of the DASI to providers. Our application measured steps walked during a 6MWT moderately well in a preoperative patient population; however, future studies are needed to improve the smartphone application’s step-counting accuracy and distance estimation algorithm.

3.

Background Preoperative resting echocardiography is often performed before noncardiac surgery, but indications for preoperative resting echocardiography are limited. This study aimed to investigate appropriateness of preoperative resting echocardiography using the Appropriate Use Criteria for Echocardiography, which encompass indications from the guidelines on perioperative cardiovascular evaluation and management and nonperioperative indications independent of the perioperative period. The authors hypothesized that patients are frequently tested without an appropriate indication. Methods Records of patients in the Truven Health MarketScan Commercial and Medicare Supplemental Databases who underwent a major abdominal surgery from 2005 to 2017 were included. These databases contain de-identified records of health services for more than 250 million patients with primary or Medicare supplemental health insurance coverage through employer-based fee-for-service, point-of-service, or capitated plans. Patients were classified based on the presence of an outpatient claim for resting transthoracic echocardiography within 60 days of surgery. Appropriateness was determined via International Classification of Diseases, Ninth Revision –Clinical Modification, and International Classification of Diseases, Tenth Revision–Clinical Modification principal and secondary diagnosis codes associated with the claims, and classified as “appropriate,” “rarely appropriate,” or “unclassifiable” using the Appropriate Use Criteria for Echocardiography. Results Among 230,535 patients in the authors’ cohort, preoperative resting transthoracic echocardiography was performed in 6.0% (13,936) of patients. There were 12,638 (91%) studies classifiable by the Appropriate Use Criteria for Echocardiography, and 1,298 (9%) were unable to be classified. Among the classifiable studies, 8,959 (71%) were deemed “appropriate,” while 3,679 (29%) were deemed “rarely appropriate.” Surveillance of chronic ischemic heart disease and uncomplicated hypertension accounted for 43% (1,588 of 3,679) of “rarely appropriate” echocardiograms. Conclusions More than one in four preoperative resting echocardiograms were considered “rarely appropriate” according to the Appropriate Use Criteria for Echocardiography. A narrow set of patient characteristics accounts for a large proportion of “rarely appropriate” preoperative resting echocardiograms. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

PDF of the Fall 2015 book

restriction factors are implicated in long-term evolutionary "arms races," in which viral antagonists drive the evolution of host proteins, and vice versa. consequently, restriction factors are remarkably variable, displaying polymorphism within species and divergence between species as a result of positive selection. this paper investigates diversity in the apobec3f (a3f) restriction factors of old world primates in order to determine whether they display evidence of involvement in an evolutionary "arms race." we speculated that genetic variability in a3f could reflect evolutionary conflict with the vif proteins of primate lentiviruses, which are known to enhance viral replication by binding and degrading host a3 proteins. a3fs of several old world primate species were genotyped, and the sequences revealed both intra-species diversity and inter-species divergence. representative rhesus macaque (macaca mulatta) sequences were cloned and tested for sensitivity to vifs from various simian immunodeficiency viruses (sivs). evolution of a3f in the rhesus lineage is not due to selection by sivs, but may reflect antagonism by another retrovirus. 1 The causative agent was soon discovered to be a lentivirus, classified as Human Immunodeficiency Virus Type 1 (HIV-1).2,3 HIV-1 and its close relative HIV Type 2 (HIV-2) arose in human populations as a result of cross-species transmission events from natural simian hosts of the Simian Immunodeficiency Viruses (SIVs). The closest simian relative of HIV-1 is the strain naturally infecting chimpanzees (SIVcpz), 4 while the closest simian relative of HIV-2 is the strain naturally infecting sooty mangabeys (SIVsm).5 Over 40 species-specific SIVs have since been identified in nonhuman primate species. A fraction of these infections result in immunodeficiency in the host species, while most are nonpathogenic in their natural hosts. 6 The SIV of a given primate species cannot readily infect a different species without undergoing numerous adaptations. Part of this adaptation process involves evading host antiviral proteins known as restriction factors. Restriction factors are host proteins that utilize numerous mechanisms to interfere with viral infections as part of the innate immune response. Some interact directly with viral factors, while others make the cellular environment unsuitable for sustained viral replication.7 These defensive genes are subject to relatively rapid evolution under the selective pressure of viral counter-restriction mechanisms, and variants that confer greater fitness to the host during a viral outbreak will become fixed in a population much faster than would normally be expected as a result of genetic drift alone. The virus, in turn, can adapt to infect the host carrying these more fit alleles, creating a new selective pressure on the host. Thus, over evolutionary time, a comparatively large number of non-synonymous, or protein-altering, mutations will be evident in genes that have participated in these virus-host "arms races." 8 Genes can be examined for e...