Perfusion imaging heterogeneity during NO inhalation distinguishes pulmonary arterial hypertension (PAH) from healthy subjects and has potential as an imaging biomarker.

BACKGROUND: Without aggressive treatment, pulmonary arterial hypertension (PAH) has a 5-year mortality of approximately 40%. A patient's response to vasodilators at diagnosis impacts the therapeutic options and prognosis. We hypothesized that analyzing perfusion images acquired before and during vasodilation could identify characteristic differences between PAH and control subjects. METHODS: We studied 5 controls and 4 subjects with PAH using HRCT and 13NN PET imaging of pulmonary perfusion and ventilation. The total spatial heterogeneity of perfusion (CV2Qtotal) and its components in the vertical (CV2Qvgrad) and cranio-caudal (CV2Qzgrad) directions, and the residual heterogeneity (CV2Qr), were assessed at baseline and while breathing oxygen and nitric oxide (O2 + iNO). The length scale spectrum of CV2Qr was determined from 10 to 110 mm, and the response of regional perfusion to O2 + iNO was calculated as the mean of absolute differences. Vertical gradients in perfusion (Qvgrad) were derived from perfusion images, and ventilation-perfusion distributions from images of 13NN washout kinetics. RESULTS: O2 + iNO significantly enhanced perfusion distribution differences between PAH and controls, allowing differentiation of PAH subjects from controls. During O2 + iNO, CV2Qvgrad was significantly higher in controls than in PAH (0.08 (0.055-0.10) vs. 6.7 × 10-3 (2 × 10-4-0.02), p < 0.001) with a considerable gap between groups. Qvgrad and CV2Qtotal showed smaller differences: - 7.3 vs. - 2.5, p = 0.002, and 0.12 vs. 0.06, p = 0.01. CV2Qvgrad had the largest effect size among the primary parameters during O2 + iNO. CV2Qr, and its length scale spectrum were similar in PAH and controls. Ventilation-perfusion distributions showed a trend towards a difference between PAH and controls at baseline, but it was not statistically significant. CONCLUSIONS: Perfusion imaging during O2 + iNO showed a significant difference in the heterogeneity associated with the vertical gradient in perfusion, distinguishing in this small cohort study PAH subjects from controls.

Impact of a Resident-Centered Interprofessional Quality Improvement Intervention on Acute Care Length of Stay.

Competency in interprofessional quality improvement and performance measurement is required by the Accreditation Council for Graduate Medical Education. We implemented an interprofessional quality improvement project to support trainee involvement in systems-level improvement to reduce hospital length of stay and engage trainees in efforts to improve the validity and reliability of clinical documentation contributing to risk-adjusted performance measures. The intervention had three components: daily interprofessional disposition huddles to discuss discharge needs, medical documentation curriculum to improve clinical data accuracy, and scheduled coding huddles to provide real-time feedback on documentation. Outcome measures included an unadjusted and risk-adjusted measure of hospital length of stay. Case severity index (CSI) served as a process measure. Statistical process control charts were used to measure change over time. The mean unadjusted length of stay decreased from 5.84 to 4.98 days. Both the unadjusted and the risk-adjusted length of stay measures exceeded the lower control limit of the statistical control chart. The CSI increased and exceeded the upper control limit of the statistical control chart. Improvements were sustained in the year following implementation. The intervention offers a model for academic institutions to satisfy new Common Program Requirements by engaging trainees in performance measurement and interprofessional improvement efforts.