Factors associated with fever after cardiac arrest: A post-hoc analysis of the FINNRESUSCI study.

BACKGROUND: Fever after cardiac arrest may impact outcome. We aimed to assess the incidence of fever in post-cardiac arrest patients, factors predicting fever and its association with functional outcome in patients treated without targeted temperature management (TTM). METHODS: The FINNRESUSCI observational cohort study in 2010-2011 included intensive care unit (ICU)-treated out-of-hospital cardiac arrest (OHCA) patients from all five Finnish university hospitals and 14 of 15 central hospitals. This post hoc analysis included those FINNRESUSCI study patients who were not treated with TH. We defined fever as at least one temperature measurement of ≥37.8°C within 72 h of ICU admission. The primary outcome was favourable functional outcome at 12 months, defined as cerebral performance category (CPC) of 1 or 2. Binary logistic regression models including witnessed arrest, bystander cardiopulmonary resuscitation (CPR), initial rhythm and delay of return of spontaneous circulation were used to compare the functional outcomes of the groups. RESULTS: There were 67,428 temperature measurements from 192 patients, of whom 89 (46%) experienced fever. Twelve-month CPC was missing in 7 patients, and 51 (28%) patients had favourable functional outcome at 12 months. The patients with shockable initial rhythms had a lower incidence of fever within 72 h of ICU admission (28% vs. 72%, p < .01), and the patients who experienced fever had a longer median return of spontaneous circulation (ROSC) delay (20 [IQR 10-30] vs. 14 [IQR 9-22] min, p < .01). Only initial non-shockable rhythm (OR 2.99, 95% CI 1.51-5.94) was associated with increased risk of fever within the first 72 h of ICU admission. Neither time in minutes nor area (minutes × degree celsius over threshold) over 37°C, 37.5°C, 38°C, 38.5°C, 39°C, 39.5°C or 40°C were significantly different in those with favourable functional outcome compared to those with unfavourable functional outcome within the first 24, 48 or 72 h from ICU admission. Fever was not associated with favourable functional outcome at 12 months (OR 0.90, 95% CI 0.44-1.84). CONCLUSIONS: Half of OHCA patients not treated with TTM developed fever. We found no association between fever and outcome.

Factors Associated With Rebound Hyperthermia After Targeted Temperature Management in Out-of-Hospital Cardiac Arrest Patients: An Explorative Substudy of the Time-Differentiated Therapeutic Hypothermia in Out-of-Hospital Cardiac Arrest Survivors Trial.

To investigate rebound hyperthermia following targeted temperature management after cardiac arrest and its impact on functional outcome. DESIGN: Post hoc analysis. SETTING: Ten European ICUs. PATIENTS: Patients included in the time-differentiated therapeutic hypothermia in out-of-hospital cardiac arrest survivors trial treated with targeted temperature management at 33°C for 48 or 24 hours. Favorable functional outcome was defined as a Cerebral Performance Category of 1 or 2 at 6 months. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 338 included patients, 103 (30%) experienced rebound hyperthermia defined as a maximum temperature after targeted temperature management and rewarming exceeding 38.5°C. Using multivariate logistic regression analysis, increasing age (odds ratio, 0.97; 95% CI, 0.95-0.99; p = 0.02) and severe acute kidney injury within 72 hours of ICU admission (odds ratio, 0.35; 95% CI, 0.13-0.91; p = 0.03) were associated with less rebound hyperthermia, whereas male gender (odds ratio, 3.94; 95% CI, 1.34-11.57; p = 0.01), highest C-reactive protein value (odds ratio, 1.04; 95% CI, 1.01-1.07; p = 0.02), and use of mechanical chest compression during cardiopulmonary resuscitation (odds ratio, 2.00; 95% CI, 1.10-3.67; p = 0.02) were associated with more rebound hyperthermia. Patients with favorable functional outcome spent less time after rewarming over 38.5°C (2.5% vs 6.3%; p = 0.03), 39°C (0.14% vs 2.7%; p < 0.01), and 39.5°C (0.03% vs 0.71%; p < 0.01) when compared with others. Median time to rebound hyperthermia was longer in the unfavorable functional outcome group (33.2 hr; interquartile range, 14.3-53.0 hr vs 6.5 hr; interquartile range, 2.2-34.1; p < 0.01). In a predefined multivariate binary logistic regression model, rebound hyperthermia was associated with decreased odds of favorable functional outcome (odds ratio, 0.42; 95% CI, 0.22-0.79). CONCLUSIONS: One-third of targeted temperature management patients experience rebound hyperthermia, and it is more common in younger male patients with an aggravated inflammatory response and those treated with a mechanical chest compression device. Later onset of rebound hyperthermia and temperatures exceeding 38.5°C associate with unfavorable outcome.

Does experience in prehospital post-resuscitation critical care affect outcomes? A retrospective cohort study.

AIMS OF THE STUDY: Helicopter Emergency Medical Services (HEMS) often provide post-resuscitation care. Our aims were to investigate whether physicians' frequent exposure to prehospital post-resuscitation care is associated with differences in (1) medical management, (2) achieving treatment targets recommended by resuscitation guidelines, (3) survival. METHODS: We conducted a retrospective cohort study using data from a national HEMS quality register. We included patients between January 1st, 2012 and September 9th, 2019 who received post-resuscitation care by a HEMS physician. We excluded patients <16 years old. For each patient we determined the number of post-resuscitation cases the physician had attended in the previous 12 months. Patients were divided in to three groups: low (0-5), intermediate (6-11) and high exposure (≥12 cases). Medical management and proportions within treatment targets were compared. Survival at 30-days and 1-year was analysed by multivariate logistic regression analysis, controlling for known prognostic factors. RESULTS: 2272 patients were analysed. Patients in the high exposure group had mechanical ventilation and vasoactive medications initiated more often (P < 0.001 and P = 0.008, respectively) and on-scene times were longer (P < 0.001). The target for blood pressure was achieved more often in this group (P = 0.026), but targets for oxygenation and ventilation were not. We did not see an association between survival and physicians' exposure to post-resuscitation care (odds ratio 0.96, 95% confidence interval 0.70-1.33 for low and 0.78, 0.56-1.08 for intermediate, compared to high exposure). CONCLUSIONS: Physicians with more, frequent exposure take a more active approach to post-resuscitation care, but this does not seem to improve survival.

Cold fluids for induction of targeted temperature management: A sub-study of the TTH48 trial.

BACKGROUND: Pre-intensive care unit (ICU) induction of targeted temperature management (TTM) with cold intravenous (i.v.) fluids does not appear to improve outcomes after in out-of-hospital cardiac arrest (OHCA). We hypothesized that this may be due to ineffective cooling and side effects. METHODS: A post hoc analysis of a sub-group of patients (n = 352) in the TTH48 trial (NCT01689077) who received or did not receive pre-ICU cooling using cold i.v. fluids. Data collection included patient characteristics, cardiac arrest factors, cooling methods, side effects and continuous core temperature measurements. The primary endpoint was the time to target temperature (TTT, <34 °C), and the secondary endpoints included the incidence of circulatory side effects, abnormal electrolyte levels and hypoxia within the first 24 h of ICU care. A difference of 1 h in the TTT was determined as clinically significant a priori. RESULTS: Of 352 patients included in the present analysis, 110 received pre-ICU cold fluids. The median time to the return of spontaneous circulation (ROSC) and TTT in the pre-ICU cold fluids group was longer than that of the group that did not receive pre-ICU cold fluids (318 vs. 281 min, p < 0.01). In a linear regression model including the treatment centre, body mass index (BMI), chronic heart failure, diabetes mellitus and time to ROSC, the use of pre-ICU cold i.v. fluids was not associated with a shorter time to the target temperature (standardized beta coefficient: 0.06, 95% CI for B -49 and 16, p  =  0.32). According to the receipt or not of pre-ICU cold i.v. fluids, there was no difference in the proportion of patients with hypoxia on ICU admission (1.8% vs. 3.3%, p =  0.43) or the proportion of patients with electrolyte abnormalities (hyponatremia: 1.8% vs. 2.9% p = 0.54; hypokalaemia: 1.8% vs. 4.5%, p =  0.20). Furthermore, there was no difference in hospital mortality between the groups. CONCLUSIONS: The initiation of TTM with cold i.v. fluids before ICU arrival did not decrease the TTT. We detected no significant between-group difference in mortality or the incidence of side effects according to the administration or not of pre-ICU cold i.v fluids.

Hatching asynchrony and brood reduction in Tengmalm's owl Aegolius funereus: the role of temporal and spatial variation in food abundance.

Hatching asynchrony is the consequence of birds initiating incubation before clutch completion. It has been suggested that variation in hatching asynchrony in owls is extensive, and therefore they should be excellent objects to study the effects of spatio-temporal variation in food abundance on this phenomenon. We examined how abundance and predictability of food affected hatching asynchrony in Tengmalm's owl Aegolius funereus (Linnaeus), which mainly feeds on voles which fluctuate in 3- to 4-year cycles in northern Europe. Hatching span averaged 6-7 days (range 0-13 days) and increased with clutch size. Food supply did not directly influence levels of hatching asynchrony but it influenced indirectly via marked among-year changes in clutch size. During the decrease phase of the vole cycle the proportion of hatchlings producing fledglings decreased with asynchrony, suggesting that chick mortality was most common among asynchronous broods when food became scarce. This finding is consistent with Lack's brood reduction hypothesis, i.e. that if food becomes scarce during the nestling period the youngest nestlings would die first without endangering the survival of the whole brood.