Effect of nitrogen (N₂) excretion on expired N₂ concentration from a two compartment lung model.

<p>Expired N₂ is shown with (solid line) and without (dotted line) N₂ excretion for a model representing a healthy adult (A), and a CF adult (B). Washout ends at expired N₂ = 1.975% (1/40^th of the starting concentration). Increase in expired N₂ at the true LCI point as a result of excreted nitrogen is indicated by the arrow.</p

Contribution of excreted nitrogen to expired nitrogen concentration from a child lung model.

<p>Expired nitrogen (N₂) is shown with (solid line) and without (dotted line) N₂ excretion for a two compartment lung model adjusted to represent a child with cystic fibrosis. N₂ excretion has been reduced by a factor of 0.45 (A) to reflect the lower body mass and blood volume, or increased by a factor 1.6 (B) to reflect increased tissue perfusion and relative cardiac output. Washout ends at expired N₂ = 1.975% (1/40^th of the starting concentration). Increase in expired N₂ at the true LCI point as a result of excreted nitrogen is indicated by the arrow.</p

Impact of nitrogen excretion and increasing dead space fraction on lung clearance index.

<p>The impact of increasing deadspace on true LCI is shown by the lower curve (grey diamonds). The impact of nitrogen (N₂) excretion on measured LCI is shown by the open circles, using true FRC. Measured LCI using measured FRC is also shown (black circles). The percent error in the measured LCI using measured FRC is shown by the black diamonds (right axis).</p

Impact of nitrogen excretion and increasing ventilation heterogeneity on lung clearance index.

<p>The impact of increasing X on LCI is shown by the lower curve (grey diamonds). The impact of nitrogen (N₂) excretion on measured LCI is shown by the open circles. The error is partially offset for by the additional error in FRC (black circles). The percentage error in LCI caused by nitrogen excretion is shown by the black diamonds (right axis).</p

Contour map showing combined impact of nitrogen excretion, ventilation heterogeneity and dead space on nitrogen washout.

<p>Impact of increasing ventilation heterogeneity (varying X between 0.5–0.9) and dead space (0.3–0.6) is shown on LCI (A) and the fractional error in LCI caused by nitrogen excretion (B). Numbers on contours represent the resulting LCI (top) or fractional error (bottom). Fractional error of 0.07 (pale grey) represents a 7% error in LCI due to nitrogen excretion.</p

Impact of increasing nitrogen excretion and ventilation heterogeneity on functional residual capacity.

<p>In the absence of nitrogen (N₂) excretion, increasing X did not change the measured FRC (black diamonds). The effect of N₂ excretion on FRC and the percentage error in measured FRC are shown by the grey diamonds and open circles respectively.</p

Comparison of four clinical risk scores in comatose patients after out-of-hospital cardiac arrest

Background and aims: Several different scoring systems for early risk stratification after out-of-hospital cardiac arrest have been developed, but few have been validated in large datasets. The aim of the present study was to compare the well-validated Out-of-hospital Cardiac Arrest (OHCA) and Cardiac Arrest Hospital Prognosis (CAHP)-scores to the less complex MIRACLE2- and Target Temperature Management (TTM)-scores. Methods: This was a post-hoc analysis of the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. Missing data were handled by multiple imputation. The primary outcome was discriminatory performance assessed as the area under the receiver operating characteristics-curve (AUROC), with the outcome of interest being poor functional outcome or death (modified Rankin Scale 4–6) at 6 months after OHCA. Results: Data on functional outcome at 6 months were available for 1829 cases, which constituted the study population. The pooled AUROC for the MIRACLE2-score was 0.810 (95% CI 0.790–0.828), 0.835 (95% CI 0.816–0.852) for the TTM-score, 0.820 (95% CI 0.800–0.839) for the CAHP-score and 0.770 (95% CI 0.748–0.791) for the OHCA-score. At the cut-offs needed to achieve specificities >95%, sensitivities were <40% for all four scoring systems. Conclusions: The TTM-, MIRACLE2- and CAHP-scores are all capable of providing objective risk estimates accurate enough to be used as part of a holistic patient assessment after OHCA of a suspected cardiac origin. Due to its simplicity, the MIRACLE2-score could be a practical solution for both clinical application and risk stratification within trials

Agreement between self‐reported and objectively assessed physical activity among out‐of‐hospital cardiac arrest survivors

Background: Low level of physical activity is a risk factor for new cardiac events in out‐of‐hospital cardiac arrest (OHCA) survivors. Physical activity can be assessed by self‐reporting or objectively by accelerometery.Aim: To investigate the agreement between self‐reported and objectively assessed physical activity among OHCA survivorsHypothesisSelf‐reported levels of physical activity will show moderate agreement with objectively assessed levels of physical activity.MethodCross‐sectional study including OHCA survivors in Sweden, Denmark, and the United Kingdom. Two questions about moderate and vigorous intensity physical activity during the last week were used as self‐reports. Moderate and vigorous intensity physical activity were objectively assessed with accelerometers (ActiGraph GT3X‐BT) worn upon the right hip for 7 consecutive days.Results: Forty‐nine of 106 OHCA survivors answered the two questions for self‐reporting and had 7 valid days of accelerometer assessment. More physically active days were registered by self‐report compared with accelerometery for both moderate intensity (median 5 [3:7] vs. 3 [0:5] days; p < 0.001) and vigorous intensity (1 [0:3] vs. 0 [0:0] days; p < 0.001). Correlations between self‐reported and accelerometer assessed physical activity were sufficient (moderate intensity: rs = 0.336, p = 0.018; vigorous intensity: rs = 0.375, p = 0.008), and agreements were fair and none to slight (moderate intensity: k = 0.269, p = 0.001; vigorous intensity: k = 0.148, p = 0.015). The categorization of self‐reported versus objectively assessed physical activity showed that 26% versus 65% had a low level of physical activity.Conclusion: OHCA survivors reported more physically active days compared with the results of the accelerometer assessment and correlated sufficiently and agreed fairly and none to slightly.</p

Neuropsychological outcome after cardiac arrest: results from a sub-study of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial

Abstract Background Cognitive impairment is common following out-of-hospital cardiac arrest (OHCA), but the nature of the impairment is poorly understood. Our objective was to describe cognitive impairment in OHCA survivors, with the hypothesis that OHCA survivors would perform significantly worse on neuropsychological tests of cognition than controls with acute myocardial infarction (MI). Another aim was to investigate the relationship between cognitive performance and the associated factors of emotional problems, fatigue, insomnia, and cardiovascular risk factors following OHCA. Methods This was a prospective case–control sub-study of The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial. Eight of 61 TTM2-sites in Sweden, Denmark, and the United Kingdom included adults with OHCA of presumed cardiac or unknown cause. A matched non-arrest control group with acute MI was recruited. At approximately 7 months post-event, we administered an extensive neuropsychological test battery and questionnaires on anxiety, depression, fatigue, and insomnia, and collected information on the cardiovascular risk factors hypertension and diabetes. Results Of 184 eligible OHCA survivors, 108 were included, with 92 MI controls enrolled. Amongst OHCA survivors, 29% performed z-score ≤ − 1 (at least borderline–mild impairment) in ≥ 2 cognitive domains, 14% performed z-score ≤ − 2 (major impairment) in ≥ 1 cognitive domain while 54% performed without impairment in any domain. Impairment was most pronounced in episodic memory, executive functions, and processing speed. OHCA survivors performed significantly worse than MI controls in episodic memory (mean difference, MD = − 0.37, 95% confidence intervals [− 0.61, − 0.12]), verbal (MD = − 0.34 [− 0.62, − 0.07]), and visual/constructive functions (MD = − 0.26 [− 0.47, − 0.04]) on linear regressions adjusted for educational attainment and sex. When additionally adjusting for anxiety, depression, fatigue, insomnia, hypertension, and diabetes, executive functions (MD = − 0.44 [− 0.82, − 0.06]) were also worse following OHCA. Diabetes, symptoms of anxiety, depression, and fatigue were significantly associated with worse cognitive performance. Conclusions In our study population, cognitive impairment was generally mild following OHCA. OHCA survivors performed worse than MI controls in 3 of 6 domains. These results support current guidelines that a post-OHCA follow-up service should screen for cognitive impairment, emotional problems, and fatigue. Trial registration ClinicalTrials.gov, NCT03543371. Registered 1 June 2018

Patient inclusion.

<p>Displaying the total Targeted Temperature Management (TTM) population, Intention-To-Treat (ITT) population and outcomes by the Cerebral Performance Category (CPC) scale.</p