Objective
To assess the efficacy and safety of high-flow nasal cannula oxygen therapy
in treating moderate hypercapnic respiratory failure in patients who cannot
tolerate or have contraindications to noninvasive mechanical
ventilation.
Methods
A prospective observational 13-month study involving subjects admitted to an
intensive care unit with or developing moderate hypercapnic respiratory
failure. Clinical and gas exchange parameters were recorded at regular
intervals during the first 24 hours. The endpoints were a oxygen saturation
between 88 and 92% along with a reduction in breathing effort (respiratory
rate) and pH normalization (≥ 7.35). Subjects were considered
nonresponders if they required ventilatory support.
Results
Thirty subjects were treated with high-flow nasal cannula oxygen therapy.
They consisted of a mixed population with chronic obstructive pulmonary
disease exacerbation, acute cardiogenic pulmonary edema, and postoperative
and postextubation respiratory failure. A nonsignificant improvement was
observed in respiratory rate (28.0 ± 0.9
versus
24.3
± 1.5, p = 0.22), which was apparent in the first four hours of
treatment. The pH improved, although normal levels were only reached after
24 hours on high-flow nasal cannula therapy (7.28 ± 0.02
versus
7.37 ± 0.01, p = 0.02). The rate of
nonresponders was 13.3% (4 subjects), of whom one needed and accepted
noninvasive mechanical ventilation and three required intubation. Intensive
care unit mortality was 3.3% (1 subject), and a patient died after discharge
to the ward (hospital mortality of 6.6%).
Conclusion
High-flow nasal cannula oxygen therapy is effective for moderate hypercapnic
respiratory failure as it helps normalize clinical and gas exchange levels
with an acceptable rate of nonresponders who require ventilatory
support.
Background
The HeartLogic algorithm measures data from multiple implantable cardioverter-defibrillator-based (ICD) sensors and combines them into a single index. The associated alert has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation.
Objective
To analyze the association between HeartLogic alerts and clinical events and to describe the implementation in clinical practice of the algorithm for remote management of HF patients.
Methods
The association between HeartLogic alerts and clinical events has been analyzed in the blinded study Phase 1 (from ICD implantation to HeartLogic alert activation) and in the following unblinded Phase 2 and 3 (after HeartLogic activation). During Phase 1, patients were managed according to the standard clinical practice and physicians were blinded to the alert status. During Phase 2 physicians reacted to alerts according to their clinical practice, while during Phase 3 they followed a standardized protocol in response to alerts.
Results
We enrolled 288 patients who received HeartLogic-enabled ICD or CRT-D at 15 centers. 101 patients contributed to Phase 1. During a median observation period of 10 [95% CI: 5 – 19] months, the HeartLogic index crossed the alert-threshold value 73 times (0.72 alerts/patient-year) in 39 patients. 8 HF hospitalizations and 2 emergency room admissions occurred in 9 patients (0.10 events/patient-year) during HeartLogic IN alert state. Other 10 minor events (HF in-office visits and non-HF hospitalization) were associated with HeartLogic alerts. During the active phases 267 patients were observed for a median follow-up of 16 [95% CI: 15 – 22] months. 277 HeartLogic alerts (0.89 alerts/patient-year) occurred in 136 patients. Thirty-three HeartLogic alerts were associated with hospitalizations for HF or with HF death (n=6), and 46 alerts were associated with unplanned in-office visits for HF. In 78 cases, HeartLogic alerts were associated with other clinically relevant events. The rate of unexplained alerts was low (0.39 alerts/patient-year). During the active phases, one HF hospitalization and one unplanned in-office visit for HF occurred when patients were in OUT of alert state. Patient phone contacts or in-person assessments were performed more frequently in Phase 3 (85%) than in Phase 2 (73%; p=0.047), while alert-triggered actions were similar in the two phases. Most alerts in both Phases (82% in 2 and 81% in 3; p=0.861) were managed remotely. The total number of patient phone contacts performed during Phase 2 was 35 (0.65 contacts/patient-year) and during Phase 3 was 287 (1.12 contacts/patient-year; p=0.002).
Conclusions
HeartLogic index was frequently associated with HF-related clinical events, with a low rate of unexplained events. The HeartLogic alert and a standardize protocol of actions allowed to remotely detect impending decompensation events and to implement clinical actions with a low workload for the centers.
Funding Acknowledgement
Type of funding sources: None.
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