The rise, fall, and future direction of computer-assisted personalized sedation.

PURPOSE OF REVIEW: The first computer-assisted personalized sedation (CAPS) device was developed to address the growing demand for routine endoscopy procedures in the United States in the early 2000s. This review will describe the environment that gave rise to CAPS and summarize the design of that first device. It will then discuss the market forces that led to the fall of CAPS, with sales of the device ending 2 years after commercialization. RECENT FINDINGS: CAPS was initially conceived as a means to enable proceduralists to administer conscious sedation with propofol safely. In the nearly 20 years since its conception, the expectations of patients and proceduralists for endoscopy sedation, have evolved from conscious sedation to deep. Due to the increased risk inherent in deep sedation, future CAPS devices should be tools for anesthesiologists, not proceduralists. SUMMARY: Over $2 billion are spent annually for anesthesia services in routine endoscopic procedures for low-risk patients; a spending rate that is not sustainable. CAPS, in an 'anesthesia oversight' model similar to medical supervision, has a future as a cost-efficient means for anesthesia services to provide sedation in endoscopy and other nonoperating room venues. Anesthesiologists should work with medical device companies and payers to develop a CAPS 'anesthesia oversight' model.

Biomechanical assessment of myocardial infarction using optical coherence elastography.

Myocardial infarction (MI) leads to cardiomyocyte loss, impaired cardiac function, and heart failure. Molecular genetic analyses of myocardium in mouse models of ischemic heart disease have provided great insight into the mechanisms of heart regeneration, which is promising for novel therapies after MI. Although biomechanical factors are considered an important aspect in cardiomyocyte proliferation, there are limited methods for mechanical assessment of the heart in the mouse MI model. This prevents further understanding the role of tissue biomechanics in cardiac regeneration. Here we report optical coherence elastography (OCE) of the mouse heart after MI. Surgical ligation of the left anterior descending coronary artery was performed to induce an infarction in the heart. Two OCE methods with assessment of the direction-dependent elastic wave propagation and the spatially resolved displacement damping provide complementary analyses of the left ventricle. In comparison with sham, the infarcted heart features a fibrotic scar region with reduced elastic wave velocity, decreased natural frequency, and less mechanical anisotropy at the tissue level at the sixth week post-MI, suggesting lower and more isotropic stiffness. Our results indicate that OCE can be utilized for nondestructive biomechanical characterization of MI in the mouse model, which could serve as a useful tool in the study of heart repair.

A novel index of hypoxemia for assessment of risk during procedural sedation.

BACKGROUND: Procedural sedation is essential for many procedures. Sedation has an excellent safety profile; however, it is not without risks. Assessment of risk using clinical outcomes in clinical studies is difficult due to their rare occurrence. Therefore, surrogate end points are frequently used in a clinical study in lieu of clinical outcomes. As a clinician integrates multiple aspects of a physiological variable to determine potential risk, a surrogate end point should consider a similar approach. In this study, we identified and tested the appropriateness of a new surrogate end point that may be used in clinical studies, area under the curve of oxygen desaturation (AUCDesat). A review of patient sedation records by anesthesiologists was conducted to assess its relationship to the anesthesia professional perception of risk. METHODS: This study was a post hoc analysis and assessment of perceived risk by anesthesiologists. It consisted of 13 U.S.-trained board-certified anesthesiologists ranking physiological variables as indicators of risk and then reviewing 204 records from 3 completed sedation studies involving the SEDASYS System. After review, each anesthesiologist assigned a Likert score based on his or her perception of risk for oversedation-related sequelae in each record. These scores were analyzed to determine their relationship to desaturation presence/absence, duration, depth, number of events, and AUCDesat that incorporates each component. RESULTS: Anesthesiologists ranked arterial oxygenation to be the most important factor in assessing risk post hoc (mean rank of 4.69 of 5, P = 0.0007 compared with next highest ranked factor-respiratory rate, N = 13). AUCDesat was better correlated to the Likert scores (rs = 0.85) when compared with the individual elements of AUCDesat, binary assessment of desaturation (rs = 0.73), desaturation depth (rs = -0.70), desaturation duration (rs = 0.70), and incidence of desaturations (rs = 0.55) (all 4 comparisons versus rs = 0.85, P < 0.0001). CONCLUSIONS: Anesthesiologists determined arterial oxygenation to be the most important physiological variable in assessing sedation risk and the potential for adverse clinical outcomes. AUCDesat, a composite index that incorporates duration, incidence, and depth of oxygen desaturation, was better correlated to the Likert scores. AUCDesat, given that it is a single numerical variable, is an ideal end point for assessment of risk of adverse clinical outcomes in clinical sedation studies. Future studies using AUCDesat and actual physiological outcomes may be useful in further defining this end point.

An assessment of computer-assisted personalized sedation: a sedation delivery system to administer propofol for gastrointestinal endoscopy.

BACKGROUND: Demand for colonoscopy and EGD procedures is increasing. Impediments to performing these examinations persist. Patients perceive these procedures as unpleasant and painful. The use of suboptimal sedatives results in inefficiency in endoscopy practices. Improving sedation methods utilizing precise control of preferred sedatives may increase patient satisfaction and practice efficiency. OBJECTIVE: Our purpose was to demonstrate the feasibility of computer-assisted personalized sedation (CAPS) for facilitating the precise administration of propofol by endoscopist/nurse teams, achieving minimal to moderate sedation in subjects undergoing routine endoscopies. DESIGN: Open label, single-center studies. SETTING: Endoscopy clinics in Charlottesville, Virginia, and Gent, Belgium. SUBJECTS: Twenty-four adults per center; 12 colonoscopies, 12 EGDs. INTERVENTIONS: Propofol sedation with CAPS by endoscopist/registered nurse care teams. MAIN OUTCOME MEASUREMENTS: Sedation level measured by modified observer's assessment of alertness/sedation (MOAA/S), recovery time measured from endoscope removal until Aldrete >/= 12, dosage of propofol, oxygen saturation, and safety assessments. RESULTS: Subjects responded to mild tactile and verbal stimuli MOAA/S = 5, 4, 3, or 2) 99% of the time. Mean propofol doses in the United States and Belgium were 65.4 and 72.1 mg, respectively. Mean recovery times were 29 and 10 seconds, respectively. Oxygen desaturation occurred in only 6% of subjects. No device-related adverse events occurred. LIMITATION: Open-label design. CONCLUSIONS: Using CAPS, the endoscopist/nurse teams precisely controlled the administration of propofol achieving minimal to moderate sedation in subjects undergoing colonoscopy and EGD procedures. Mean propofol dosage was low and post-procedure recovery times were rapid. The device performed well when operated by the endoscopist/nurse team, with no device-related adverse events.