Process Improvement Initiative for the Perioperative Management of Patients With a Cardiovascular Implantable Electronic Device.

BACKGROUND: Economic, personnel, and procedural challenges often complicate and interfere with efficient and safe perioperative care of patients with cardiovascular implantable electronic devices (CIEDs). In the context of a process improvement initiative, we created and implemented a comprehensive anesthesiologist-run perioperative CIED service to respond to all routine requests for perioperative CIED consultations at a large academic medical center. This study was designed to determine whether this new care model was associated with improved operating room efficiency, reduced institutional cost, and adequate patient safety. METHODS: We included patients with a CIED and a concurrent cohort of patients with the same eligibility criteria but without a CIED who underwent first-case-of-the-day surgery during the periods between February 1, 2008, and August 17, 2010 (preintervention) and between March 4, 2012, and August 1, 2014 (postintervention). The primary end point was delay in first-case-of-the day start time. We used multiple linear regression to compare delays in start times during the preintervention and postintervention periods and to adjust for potential confounders. A patient safety database was queried for CIED-related complications. Cost analysis was based on labor minutes saved and was calculated using nationally published administrative estimates. RESULTS: A total of 18,148 first-case surgical procedures were performed in 15,100 patients (preintervention period-7293 patients and postintervention period-7807 patients). Of those, 151 (2.1%) patients had a CIED in the preintervention period, and 146 (1.9%) had a CIED in the postintervention period. After adjustment for imbalances in baseline characteristics (age, American Society of Anesthesiologists physical status, and surgical specialty), the difference in mean first-case start delay between the postintervention and preintervention periods in the cohort of patients with a CIED was -16.7 minutes (95% confidence interval [CI], -26.1 to -7.2). The difference in mean delay between the postintervention and preintervention periods in the cohort without a CIED was -4.7 minutes (95% CI, -5.4 to -3.9). There were 3 CIED-related adverse events during the preintervention period and none during the postintervention period. Based on reduction in first-case start delay, the intervention was associated with cost savings (estimated institutional savings $14,102 annually, or $94.06 per CIED patient), with a return on investment ratio of 2.18 over the course of the postintervention period. CONCLUSIONS: Based on our experience, specially trained anesthesiologists can provide efficient and safe perioperative care for patients with CIEDs. Other centers may consider implementing a similar strategy as our specialty adopts the perioperative surgical home model.

Intra-tumoral heterogeneity of gemcitabine delivery and mass transport in human pancreatic cancer.

There is substantial heterogeneity in the clinical behavior of pancreatic cancer and in its response to therapy. Some of this variation may be due to differences in delivery of cytotoxic therapies between patients and within individual tumors. Indeed, in 12 patients with resectable pancreatic cancer, we previously demonstrated wide inter-patient variability in the delivery of gemcitabine as well as in the mass transport properties of tumors as measured by computed tomography (CT) scans. However, the variability of drug delivery and transport properties within pancreatic tumors is currently unknown. Here, we analyzed regional measurements of gemcitabine DNA incorporation in the tumors of the same 12 patients to understand the degree of intra-tumoral heterogeneity of drug delivery. We also developed a volumetric segmentation approach to measure mass transport properties from the CT scans of these patients and tested inter-observer agreement with this new methodology. Our results demonstrate significant heterogeneity of gemcitabine delivery within individual pancreatic tumors and across the patient cohort, with gemcitabine DNA incorporation in the inner portion of the tumors ranging from 38 to 74% of the total. Similarly, the CT-derived mass transport properties of the tumors had a high degree of heterogeneity, ranging from minimal difference to almost 200% difference between inner and outer portions of the tumor. Our quantitative method to derive transport properties from CT scans demonstrated less than 5% difference in gemcitabine prediction at the average CT-derived transport value across observers. These data illustrate significant inter-patient and intra-tumoral heterogeneity in the delivery of gemcitabine, and highlight how this variability can be reproducibly accounted for using principles of mass transport. With further validation as a biophysical marker, transport properties of tumors may be useful in patient selection for therapy and prediction of therapeutic outcome.

Rationale for the fundamental use of surgical Energy™ (FUSE) curriculum assessment: focus on safety.

BACKGROUND: Almost all surgical procedures involve the use of devices that apply energy to tissue. Adverse events can occur if the devices are not used appropriately. The SAGES' Fundamental Use of Surgical Energy™ (FUSE) program will include a curriculum and certification examination to address this safety issue. The aim of this study was to determine the self-perceived knowledge of practicing surgeons related to energy-based devices and identify areas to emphasize in the assessment component of FUSE. METHODS: Psychometric experts led the test development process. During a 2-day retreat, a multidisciplinary group defined 63 test objectives assessing the knowledge and skills required to use energy-based surgical instruments safely (job task analysis). A survey was sent to a sample of 103 SAGES leaders and others in the test target audience to determine the number of items to use for the certification examination. Participants rated each objective for frequency, relevance, and importance on a 1-7 scale with the means used to create a weighted scale. The survey also included five self-assessment questions. RESULTS: Fifty surveys were completed; only 28 % of respondents considered themselves "experts." The most common source of knowledge was "industry sales representative or course" (42 %). The highest weighted topic was "Prevention of Adverse Events with Electrosurgery." The highest-rated objectives (>6 out of 7) were "Identify various mechanisms whereby electrosurgical injuries may occur," "Identify patient protection measures for setup and settings for the electrosurgical unit," and "Identify circumstances, mechanisms, and prevention of dispersive electrodes-related injury." CONCLUSIONS: Although basic and advanced energy-based devices are commonly used, training has been largely dependent upon industry representatives or industry-sponsored courses. Few surgeons consider themselves experts in the mechanisms of action and the appropriate and safe use of energy-based surgical devices. Competencies that emphasize electrosurgical safety were viewed as most important for the FUSE certification examination.

Case report: use caution when applying magnets to pacemakers or defibrillators for surgery.

The application of a magnet to a pacemaker (intended to cause asynchronous pacing) or implanted cardioverter defibrillator (intended to prevent shocks) during surgery without a clear understanding of actual magnet function(s) or precautions can have unexpected, untoward, or harmful consequences. In this report, we present 3 cases in which inadequate assessment of cardiac implanted electronic device (CIED) function, coupled with magnet application, contributed to or resulted in inappropriate antitachycardia pacing or shocks, CIED damage, or patient injury. Although these cases might be rare, they reinforce the need for a timely, detailed preoperative review of CIED function and programming as recommended by the American Society of Anesthesiologists and the Heart Rhythm Society.

Radiography of pacemakers and implantable cardioverter defibrillators.

OBJECTIVE: The purpose of this article is to review the normal and abnormal radiographic appearances of cardiac pacemaker and implantable cardioverter defibrillator systems. CONCLUSION: Chest radiographs showing pacemakers and implantable cardioverter defibrillators contain identifying and clinically relevant information, such as MRI compatibility and possible malfunction. Accurate and timely reporting of these features provides important information that can improve patient care.

Proton dose perturbations caused by high-voltage leads from implanted cardioverter defibrillators.

An increasing number of patients undergoing proton radiotherapy have cardiac implantable electrical devices (CIEDs). We recently encountered a situation in which a high-voltage coil on a lead from an implanted cardiac defibrillator was located within the clinical treatment volume for a patient receiving proton radiotherapy for esophageal cancer. To study the effects of the lead on the dose delivery, we placed a high-Z CIED lead at both the center and the distal edge of a clinical spread-out Bragg peak (SOBP) in a water phantom, in both a stationary position and with the lead moving in a periodic pattern to simulate cardiorespiratory movement. We then calculated planned doses using a commercial proton treatment planning system (TPS), and compared them with the doses delivered in the phantom, measured using radiographic film. Dose profiles from TPS-calculated and measured dose distributions showed large pertubrations in the delivered proton dose in the vicinity of the CIED lead when it was not moving. The TPS predicted perturbations up to 20% and measurements revealed perturbations up to 35%. However, the perturbations were less than 3% when the lead was moving. Greater dose perturbations were seen when the lead was placed at the distal edge of the SOBP than when it was placed in the center of the SOBP. We conclude that although cardiorespiratory motion of the lead mitigates some of the perturbations, the effects of the leads should be considered and steps taken to reduce these effects during the treatment planning process.

Preoperative evaluation of the oncology patient.

This review focuses on the unique perioperative concerns of patients with cancer undergoing surgery. Importantly, not all surgical procedures are intended as cures: some patients who have cancer also undergo surgery for noncancer issues. Also, many of these patients have undergone prior chemotherapy and/or radiation therapy that can introduce perioperative concerns. These previous treatments, unique to patients with cancer, can adversely affect their cardiovascular, pulmonary, gastrointestinal, renal, and endocrine systems. This article also summarizes many important effects of a wide variety of chemotherapy agents in use today.

Cardiorespiratory Events Associated With Ophthalmic Surgery: A Single-Center, Retrospective Records Review of 130 775 Patients, 1999-2015.

Purpose: The most recent study of ophthalmic surgery morbidity and mortality was published in 1995, with a patient study population from 1977 to 1988. The present study reports surgical outcomes from a single-center, retrospective analysis of patient records from 1999 to 2015. Methods: Three International Classification of Diseases-9-CM codes for cardiorespiratory events were searched in the discharge diagnoses in an eye hospital over a 16-year period. The overall mortality and preoperative risk factors were analyzed, including the type of anesthetic, type of surgery, medical comorbidities, and bradycardia preceding the cardiac events. Results: Between February 1, 1999 and October 1, 2015, a total of 130 775 patients presented for ophthalmic surgery. Fifty-nine patients (0.45 per 1000) experienced a cardiorespiratory event. Of the 59 patients, 14 patients had a cardiorespiratory arrest, 9 of whom died during the perioperative period. Of the remaining 45 patients, 29 had significant adverse events needing some form of advanced monitoring, evaluation, and/or intervention. There was a significantly greater prevalence of diabetes among patients who had a cardiorespiratory event (P < .001). Conclusions: The major risk factor associated with ophthalmic surgery morbidity and mortality was diabetes with its associated complications of autonomic neuropathy, nephropathy, and retinopathy. Of the 9 patients who died, 8 were diabetic with proliferative diabetic retinopathy and renal insufficiency/failure. The ninth mortality was secondary to a venous air embolism during ocular air infusion. The adage that "the eye is the window to our overall health" seems to be correct.

Radiotherapy-Induced Malfunction in Contemporary Cardiovascular Implantable Electronic Devices: Clinical Incidence and Predictors.

IMPORTANCE: Risk stratification and management paradigms for patients with cardiovascular implantable electronic devices (CIEDs) requiring radiotherapy (RT) vary widely and are based on limited clinical data. OBJECTIVE: To identify the incidence and predictors of CIED malfunction and describe associated clinical consequences in a large cohort of patients treated with photon- and electron-based RT. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of all patients with a functioning CIED who underwent RT between August 2005 and January 2014 with CIED interrogation data following RT at an academic cancer center. We identified 249 courses of photon- and electron-based RT in 215 patients (123 pacemakers [57%]; 92 implantable cardioverter-defibrillators [43%]). Substantial neutron production was generated in 71 courses (29%). EXPOSURE: Implantation of CIED with subsequent therapeutic radiation treatment (neutron producing with 15- or 18-MV photons and non-neutron producing with electrons, GammaKnife, or 6-MV photons). MAIN OUTCOMES AND MEASURES: Malfunction of CIED, characterized as single-event upset (data loss, parameter resets, unrecoverable resets), and delayed effects including signal interference, pacing threshold changes, and premature battery depletion. RESULTS: Malfunction of CIED attributable to RT occurred during 18 courses (7%), with 15 CIEDs experiencing single-event upsets, and 3, transient signal interference. All single-event upsets occurred during neutron-producing RT, at a rate of 21%, 10%, and 34% per neutron-producing course for CIEDs, pacemakers, and implantable cardioverter-defibrillators, respectively. No single-event upsets were found among 178 courses of non-neutron-producing RT. Incident CIED dose did not correlate with device malfunction. Patients treated to the abdomen and pelvis region were more likely to undergo a single-event upset (hazard ratio, 5.2 [95% CI, 1.2-22.6]; P = .03). Six patients with a CIED parameter reset developed clinical symptoms: 3 experienced hypotension and/or bradycardia, 2 experienced abnormal chest ticking consistent with pacemaker syndrome, and 1 developed congestive heart failure. The 3 episodes of signal interference did not result in clinical effects. No delayed malfunctions were directly attributed to RT. CONCLUSIONS AND RELEVANCE: In a cohort of contemporary CIEDs, all cases of single-event upset malfunction occurred in the setting of notable neutron production, at a rate of 21% for neutron-producing RT and 0% for non-neutron-producing RT. Where clinically feasible, the use of non-neutron-producing RT is recommended. Given the lack of correlation between CIED malfunction and incident dose observed up to 5.4 Gy, invasive CIED relocation procedures in these settings can be minimized.

Peripheral nerve stimulators can inhibit monitor display of pacemaker pulses.

The operating room monitors that are currently available use digital signal processing techniques to acquire and display electrocardiograms (ECGs). As a result, pacemaker impulses are interpreted as noise and thus filtered from the final display. For these signals to be displayed, the monitor must be manually reconfigured away from the default state. However, the displaying of the pacemaker impulse remains a digital process, and the monitor "paints" this signal (and other noise) back into the displayed ECG as a pacemaker impulse. Two surgical cases are reported that demonstrate monitor malfunction in systems with digitally processed ECGs during application of nerve stimulator signals to the patient. In one case, application of a 100-Hz tetany signal completely abolished the displayed pacemaker pulses. In the second case, application of a 50-Hz tetany signal abolished appropriate display but caused the monitor to display artifactual pacemaker pulses. Knowledge of undesirable monitor behavior can reduce inappropriate therapy in the operating room.

Effect of radiofrequency energy emitted from monopolar "Bovie" instruments on cardiac implantable electronic devices.

BACKGROUND: The monopolar "Bovie" instrument emits radiofrequency energy that can disrupt the function of other implanted electronic devices through a phenomenon termed electromagnetic interference. The purpose of this study was to quantify the electromagnetic interference occurring on cardiac implantable devices (CIEDs) resulting from monopolar instrument use in common, modifiable clinical scenarios. STUDY DESIGN: Three anesthetized pigs underwent CIED placement (1 pacemaker and 2 defibrillators). Electromagnetic interference was quantified when changing the monopolar instrument parameters of generator power, generator mode, surgical technique, orientation of active electrode cord, pathway of current vector, and proximity of active electrode to the CIED. RESULTS: Monopolar instrument parameters that decreased the electromagnetic interference occurring on the CIED included decreasing generator power from 60 W to 30 W (p < 0.001), using cut mode rather than coag mode (p < 0.001), using desiccation technique rather than fulguration technique (p < 0.001), orienting the active electrode cord from the feet rather than across the chest wall (p < 0.001), and avoiding the current vector from crossing the CIED system (p < 0.001). Increasing the distance between the active electrode tool and the CIED system decreased electromagnetic interference occurring on the CIED in a dose-response fashion up to a distance of 10 cm (ANOVA, p < 0.001), after which the magnitude of electromagnetic interference remained constant. CONCLUSIONS: Electromagnetic interference occurring on CIEDs resulting from monopolar instruments is minimized by decreasing generator power, using cut mode, using desiccation technique, orienting the active electrode cord from the feet, avoiding the current vector for crossing the CIED system, and increasing the distance between the active electrode and the CIED. Surgeons and operating room staff can minimize electromagnetic interference on CIEDs during monopolar instrument use by accounting for these modifiable clinical factors.

Transport properties of pancreatic cancer describe gemcitabine delivery and response.

BACKGROUND: The therapeutic resistance of pancreatic ductal adenocarcinoma (PDAC) is partly ascribed to ineffective delivery of chemotherapy to cancer cells. We hypothesized that physical properties at vascular, extracellular, and cellular scales influence delivery of and response to gemcitabine-based therapy. METHODS: We developed a method to measure mass transport properties during routine contrast-enhanced CT scans of individual human PDAC tumors. Additionally, we evaluated gemcitabine infusion during PDAC resection in 12 patients, measuring gemcitabine incorporation into tumor DNA and correlating its uptake with human equilibrative nucleoside transporter (hENT1) levels, stromal reaction, and CT-derived mass transport properties. We also studied associations between CT-derived transport properties and clinical outcomes in patients who received preoperative gemcitabine-based chemoradiotherapy for resectable PDAC. RESULTS: Transport modeling of 176 CT scans illustrated striking differences in transport properties between normal pancreas and tumor, with a wide array of enhancement profiles. Reflecting the interpatient differences in contrast enhancement, resected tumors exhibited dramatic differences in gemcitabine DNA incorporation, despite similar intravascular pharmacokinetics. Gemcitabine incorporation into tumor DNA was inversely related to CT-derived transport parameters and PDAC stromal score, after accounting for hENT1 levels. Moreover, stromal score directly correlated with CT-derived parameters. Among 110 patients who received preoperative gemcitabine-based chemoradiotherapy, CT-derived parameters correlated with pathological response and survival. CONCLUSION: Gemcitabine incorporation into tumor DNA is highly variable and correlates with multiscale transport properties that can be derived from routine CT scans. Furthermore, pretherapy CT-derived properties correlate with clinically relevant endpoints. TRIAL REGISTRATION: Clinicaltrials.gov NCT01276613. FUNDING: Lustgarten Foundation (989161), Department of Defense (W81XWH-09-1-0212), NIH (U54CA151668, KCA088084).