Clinical Implications of Changes in Respiratory Instability Following Transcatheter Aortic Valve Replacement

Background: Respiratory instability, which can be quantified using respiratory stability time (RST), is associated with the severity and prognostic impact of the disease in patients with chronic heart failure. However, its clinical implications in patients with severe aortic stenosis receiving transcatheter aortic valve replacement (TAVR) remain unknown. Methods: Patients who received TAVR and had paired measurements of RST at a baseline and one week following TAVR were prospectively included. Changes in RST following TAVR and its impact on post-TAVR heart failure readmissions were investigated. Results: Seventy-one patients (median age, 86 years old; 35% men) were included. The baseline RST was correlated with the severity of heart failure including elevated levels of plasma B-type natriuretic peptide (p < 0.05 for all). RST improved significantly following TAVR from 34 (26, 37) s to 36 (33, 38) s (p < 0.001). Post-TAVR lower RST (<33 s, n = 18) was associated with a higher 2-year cumulative incidence of heart failure readmission (21% vs. 8%, p = 0.039) with a hazard ratio of 5.47 (95% confidence interval 0.90–33.2). Conclusion: Overall, respiratory instability improved following TAVR. Persistent respiratory instability following TAVR was associated with heart failure recurrence.

Intraoperative Anaphylactic Reaction: Is it the Floseal?

When hemodynamic or respiratory instability occurs intraoperatively, the inciting event must be determined so that a therapeutic plan can be provided to ensure patient safety. Although generally uncommon, one cause of cardiorespiratory instability is anaphylactic reactions. During anesthetic care, these most commonly involve neuromuscular blocking agents, antibiotics, or latex. Floseal is a topical hemostatic agent that is frequently used during orthopedic surgical procedures to augment local coagulation function and limit intraoperative blood loss. As these products are derived from human thrombin, animal collagen, and animal gelatin, allergic phenomenon may occur following their administration. We present 2 pediatric patients undergoing posterior spinal fusion who developed intraoperative hemodynamic and respiratory instability following use of the topical hemostatic agent, Floseal. Previous reports of such reactions are reviewed, and the perioperative care of patients with intraoperative anaphylaxis is discussed.

Abstract 16832: Acute Effects of Adaptive Servo-Ventilation on Diurnal Respiratory Instability Quantified Using Novel Method in Patients With Heart Failure

Introduction: Various types of abnormal breathing including Cheyne-Stokes respiration are frequently observed in patients with heart failure (HF). Although abnormal breathing is recognized as an indicator of poor prognosis, it has not been quantitatively evaluated. Therefore, we proposed a novel method for quantifying respiratory instability during abnormal breathing in patients with HF, and evaluated acute effect of adaptive servo-ventilation (ASV). Methods: Diurnal respiratory waveform during wakefulness was obtained by nasal pressure sensor (SAS-3200, Nihon Kohden) for 15 minutes. Analysis method for respiratory waveform was as follows. The inspiration slope (IS) was calculated as the ratio of the peak inspiratory amplitude over time-interval from peak expiration to peak inspiration, and interquartile ranges (IQR) of all consecutive ISs during 15-min were evaluated (Figure, top). Heart failure patients with abnormal breathing have breath-by-breath change in IS and therefore have high IQR score (e.g., Figure bottom left). Firstly, we compared IQR in five healthy volunteers (age 36 +/- 3) and 16 patients with HF (age 66 +/- 17 years old, NYHA 3.3 +/- 0.6, LVEF 31 +/- 12%). Secondly, we compared IQR in all 16 patients with HF during spontaneous respiration and ASV (e.g., Figure bottom right). Results: IQR in healthy volunteers were significantly lower compared with patients with HF (0.11 +/- 0.05 vs. 0.29 +/- 0.15, p<0.01). In patients with HF, ASV reduced IQR (0.29 +/- 0.15 vs. 0.14 +/- 0.10, p<0.01 vs spontaneous respiration). Conclusions: This novel method effectively quantified respiratory instability in HF patients. This quantitative evaluation method of respiratory instability may become one of the heart failure management tools.