Outcome in refractory out-of-hospital cardiac arrest before and after implementation of an ECPR protocol.

AIM: To compare the outcomes in patients with refractory out-of-hospital cardiac arrest (OHCA) fulfilling the criteria for extracorporeal cardiopulmonary resuscitation (ECPR) before and after implementation of an ECPR protocol, whether the patient received ECPR or not. METHODS: We compared cardiac arrest registry data before (2014-2015) and after (2016-2019) implementation of the ECPR protocol. The ECPR criteria were presumed cardiac origin, witnessed arrest with ventricular fibrillation, bystander CPR, age 18-65, advanced life support (ALS) within 15 min and ALS > 10 min without return of spontaneous circulation (ROSC). The primary outcome was 30-day survival; the secondary outcomes were sustained ROSC, neurological outcome and the proportion of patients transported with ongoing ALS. RESULTS: There were 1086 and 3135 patients in the pre- and post-implementation sample; 48 (4%) and 100 (3%) met the ECPR criteria, respectively. Of these, 21 (44%) vs. 37 (37%) were alive after 30 days, p = 0.4, and 30 (63%) vs. 50 (50%) achieved sustained ROSC, p = 0.2. All survivors in the pre-implementation sample had cerebral performance category 1-2 vs. 30 (81%) in the post-implementation sample, p = 0.03. Of the patients fulfilling the ECPR criteria, 7 (15%) and 26 (26%), p = 0.1, were transported with ongoing ALS in the pre- and post-implementation sample, respectively. CONCLUSIONS: There were no differences in 30-day survival or prehospital ROSC in patients with refractory OHCA before and after initiation of an ECPR protocol.

Correction: Associations between changes in precerebral blood flow and cerebral oximetry in the lower body negative pressure model of hypovolemia in healthy volunteers.

[This corrects the article DOI: 10.1371/journal.pone.0219154.].

Associations between changes in precerebral blood flow and cerebral oximetry in the lower body negative pressure model of hypovolemia in healthy volunteers.

Reductions in cerebral oxygen saturation (ScO2) measured by near infra-red spectroscopy have been found during compensated hypovolemia in the lower body negative pressure (LBNP)-model, which may reflect reduced cerebral blood flow. However, ScO2 may also be contaminated from extracranial (scalp) tissues, mainly supplied by the external carotid artery (ECA), and it is possible that a ScO2 reduction during hypovolemia is caused by reduced scalp, and not cerebral, blood flow. The aim of the present study was to explore the associations between blood flow in precerebral arteries and ScO2 during LBNP-induced hypovolemia. Twenty healthy volunteers were exposed to LBNP 20, 40, 60 and 80 mmHg. Blood flow in the internal carotid artery (ICA), ECA and vertebral artery (VA) was measured by Doppler ultrasound. Stroke volume for calculating cardiac output was measured by suprasternal Doppler. Associations of changes within subjects were examined using linear mixed-effects regression models. LBNP reduced cardiac output, ScO2 and ICA and ECA blood flow. Changes in flow in both ICA and ECA were associated with changes in ScO2 and cardiac output. Flow in the VA did not change during LBNP and changes in VA flow were not associated with changes in ScO2 or cardiac output. During experimental compensated hypovolemia in healthy, conscious subjects, a reduced ScO2 may thus reflect a reduction in both cerebral and extracranial blood flow.

Impact of Norepinephrine on Regional Cerebral Oxygenation During Cardiopulmonary Bypass.

OBJECTIVES: Norepinephrine is used to increase mean arterial pressure during cardiopulmonary bypass. However, it has been suggested that norepinephrine could constrict cerebral arteries, reducing cerebral blood flow. The aim of this study, therefore, was to explore whether there was an association between doses of norepinephrine to maintain mean arterial pressure at ≈80 mmHg during cardiopulmonary bypass and cerebral oxygen saturation measured using near-infrared spectroscopy. DESIGN: Observational study. SETTING: University hospital. PARTICIPANTS: Patients undergoing cardiac surgery (n = 45) using cardiopulmonary bypass. INTERVENTIONS: Norepinephrine was administered to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: From initiation of cardiopulmonary bypass to removal of the aortic cross-clamp, norepinephrine dose, mean arterial pressure, partial pressure of arterial carbon dioxide, partial pressure of arterial oxygen, hemoglobin, and pump flow values were averaged over 1 minute, giving a total of 3,460 data points entered as covariates in a linear mixed model for repeated measurements, with cerebral oxygen saturation measured using near-infrared spectroscopy as outcome. There was no statistically significant association between norepinephrine dose to maintain mean arterial pressure and cerebral oxygen saturation (p = 0.46) in this model. CONCLUSIONS: Administration of norepinephrine to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass was not associated with statistically significant changes in cerebral oxygen saturation. These results indicated that norepinephrine could be used to increase mean arterial pressure during cardiopulmonary bypass without reducing cerebral oxygen saturation.

Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device.

Respiratory variations in the photoplethysmographic waveform amplitude predict fluid responsiveness under certain conditions. Processing of the photoplethysmographic signal may vary between different devices, and may affect respiratory amplitude variations calculated by the standard formula. The aim of the present analysis was to explore agreement between respiratory amplitude variations calculated using photoplethysmographic waveforms available from two different pulse oximeters. Analysis of registrations before and after fluid loads performed before and after open-heart surgery (aortic valve replacement and/or coronary artery bypass grafting) with patients on controlled mechanical ventilation. Photoplethysmographic (Nellcor and Masimo pulse oximeters) and arterial pressure waveforms were recorded. Amplitude variations induced by ventilation were calculated and averaged over ten respiratory cycles. Agreements for absolute values are presented in scatterplots (with least median square regression through the origin, LMSO) and Bland-Altman plots. Agreement for trending presented in a four-quadrant plot. Agreement between respiratory photoplethysmographic amplitude variations from the two pulse oximeters was poor with LMSO ΔPOPNellc = 1.5 × ΔPOPMas and bias ± limits of agreement 7.4 ± 23 %. Concordance rate with a fluid load was 91 %. Agreement between respiratory variations in the photoplethysmographic waveform amplitude calculated from the available signals output by two different pulse oximeters was poor, both evaluated by LMSO and Bland-Altman plot. Respiratory amplitude variations from the available signals output by these two pulse oximeters are not interchangeable.

Agreement between stroke volume measured by oesophageal Doppler and uncalibrated pulse contour analysis during fluid loads in severe aortic stenosis.

The purpose of this analysis was to study agreement and trending of stroke volume measured by oesophageal Doppler and 3rd generation Vigileo during fluid loads in patients with severe aortic stenosis. Observational study in 32 patients (30 analyzed) scheduled for aortic valve replacement due to severe aortic stenosis. After induction of anesthesia and before start of surgery, hemodynamic registrations for 1 min were obtained before and after a fluid load. Agreement between stroke volume measured by oesophageal Doppler (SVOD) and Vigileo (SVVig) was evaluated in Bland-Altman plot and trending in four-quadrant and polar plots. Bias ± limits of agreement (LOA) between SVOD and SVVig was 24 ± 37 ml (percentage error 45%). Concordance of the two methods from before to after a fluid load was 100%. Angular bias ± LOA was 12° ± 28°. Absolute values of SVOD and SVVig agreed poorly, but changes were highly concordant during fluid loads in aortic stenosis patients. The angular agreement indicated acceptable trending. The two measurement methods are not interchangeable in patients with aortic stenosis.