Project description:ObjectivesThe manipulation of arterial carbon dioxide tension is associated with differential mortality and neurologic injury in intensive care and cardiac arrest patients; however, few studies have investigated this relationship in patients on venoarterial extracorporeal membrane oxygenation. We investigated the association between the initial arterial carbon dioxide tension and change over 24 hours on mortality and neurologic injury in patients undergoing venoarterial extracorporeal membrane oxygenation for cardiac arrest and refractory cardiogenic shock.DesignRetrospective cohort analysis of adult patients recorded in the international Extracorporeal Life Support Organization Registry.SettingData reported to the Extracorporeal Life Support Organization from all international extracorporeal membrane oxygenation centers during 2003-2016.PatientsAdult patients (≥ 18 yr old) supported with venoarterial extracorporeal membrane oxygenation.InterventionsNone.Measurements and main resultsA total of 7,168 patients had sufficient data for analysis at the initiation of venoarterial extracorporeal membrane oxygenation, 4,918 of these patients had arterial carbon dioxide tension data available at 24 hours on support. The overall in-hospital mortality rate was 59.9%. A U-shaped relationship between arterial carbon dioxide tension tension at extracorporeal membrane oxygenation initiation and in-hospital mortality was observed. Increased mortality was observed with a arterial carbon dioxide tension less than 30 mm Hg (odds ratio, 1.26; 95% CI, 1.08-1.47; p = 0.003) and greater than 60 mm Hg (odds ratio, 1.28; 95% CI, 1.10-1.50; p = 0.002). Large reductions (> 20 mm Hg) in arterial carbon dioxide tension over 24 hours were associated with important neurologic complications: intracranial hemorrhage, ischemic stroke, and/or brain death, as a composite outcome (odds ratio, 1.63; 95% CI, 1.03-2.59; p = 0.04), independent of the initial arterial carbon dioxide tension.ConclusionsInitial arterial carbon dioxide tension tension was independently associated with mortality in this cohort of venoarterial extracorporeal membrane oxygenation patients. Reductions in arterial carbon dioxide tension (> 20 mm Hg) from the initiation of extracorporeal membrane oxygenation were associated with neurologic complications. Further prospective studies testing these associations are warranted.
Project description:Extracorporeal membrane oxygenation (ECMO) is a technique widely used worldwide to improve gas exchange. Changes in ECMO settings affect both oxygen and carbon dioxide. The impact on oxygenation can be followed closely by continuous pulse oximeter. Conversely, carbon dioxide equilibrates much slower and is not usually monitored directly.We investigated the time to stabilization of arterial carbon dioxide partial pressure (PaCO2) following step changes in ECMO settings in 5 apnoeic porcine models under veno-venous ECMO support with polymethylpentene membranes. We collected sequential arterial blood gases at a pre-specified interval of 50 min using a sequence of standardized blood and sweep gas flow combinations.Following the changes in ECMO parameters, the kinetics of carbon dioxide was dependent on sweep gas and ECMO blood flow. With a blood flow of 1500 mL/min, PaCO2 takes longer than 50 min to equilibrate following the changes in sweep gas flow. Furthermore, the sweep gas flow from 3.0 to 10.0 L/min did not significantly affect PaCO2. However, with a blood flow of 3500 mL/min, 50 min was enough for PaCO2 to reach the equilibrium and every increment of sweep gas flow (up to 10.0 L/min) resulted in additional reductions of PaCO2.Fifty minutes was enough to reach the equilibrium of PaCO2 after ECMO initiation or after changes in blood and sweep gas flow with an ECMO blood flow of 3500 ml/min. Longer periods may be necessary with lower ECMO blood flows.
Project description:The primary objective was to investigate the association between partial pressure of carbon dioxide (PaCO2) change after extracorporeal membrane oxygenation (ECMO) initiation and neurologic outcome in neonates treated for respiratory failure. A retrospective analysis of the Extracorporeal Life Support Organization (ELSO) database including newborns supported by ECMO for respiratory indication during 2015-2020. The closest Pre-ECMO (Pre-ECMO PaCO2) and at 24 hours after ECMO initiation (H24 PaCO2) PaCO2 values allowed to calculate the relative change in PaCO2 (Rel Δ PaCO2 = [H24 PaCO2 - Pre-ECMO PaCO2]/Pre-ECMO PaCO2). The primary outcome was the onset of any acute neurologic event (ANE), defined as cerebral bleeding, ischemic stroke, clinical or electrical seizure, or brain death during ECMO. We included 3,583 newborns (median age 1 day [interquartile range {IQR}, 1-3], median weight 3.2 kg [IQR, 2.8-3.6]) from 198 ELSO centers. The median Rel Δ PaCO2 value was -29.9% [IQR, -46.2 to -8.5]. Six hundred nine (17%) of them had ANE (405 cerebral bleedings, 111 ischemic strokes, 225 seizures, and 6 brain deaths). Patients with a decrease of PaCO2 > 50% were more likely to develop ANE than others (odds ratio [OR] 1.78, 95% confidence interval [CI], 1.31-2.42, p < 0.001). This was still observed after adjustment for all clinically relevant confounding factors (adjusted OR 1.94, 95% CI, 1.29-2.92, p = 0.001). A significant decrease in PaCO2 after ECMO start is associated with ANE among neonates requiring ECMO for respiratory failure. Cautious PaCO2 decrease should be considered after start of ECMO therapy.
Project description:Mechanical ventilation (MV) represents a lifesaving treatment for patients with respiratory failure, but it could be harmful through the development of ventilator-induced lung injury (VILI). In patients with acute respiratory distress syndrome (ARDS), protective MV strategies with low tidal volume to minimize VILI have been demonstrated to reduce lung injury and mortality. However, they can be limited by the emergence of uncontrolled hypercapnia. Similarly, in COPD patients, noninvasive MV failure often is associated with a progressive rise in arterial CO2 and need for endotracheal intubation, with higher risk of hospital mortality. Minimally invasive extracorporeal CO2 removal systems (ECCO2R) theoretically can remove the entire amount of the CO2 produced in the body per minute. In ARDS patients, ECCO2R may further reduce the risk of VILI ensuring ultraprotective MV and avoiding hypercapnia. In patients with exacerbation of COPD, ECCO2R may help to avoid intubation or facilitate weaning from invasive MV. In intensive care unit, concomitant renal and respiratory failure with MV is one of the strongest risk factors for hospital mortality. Combining ECCO2R and renal replacement therapy may support respiratory and renal functions and limit the side effects of MV. However, the need for systemic anticoagulation and the related risk of bleeding still represent a concern for a wider application of ECCO2R devices. In conclusion, ECCO2R is an effective support therapy to MV to limit its invasiveness and side effects, but its efficacy and safety must be proven in well-designed clinical trials. Objectives This chapter will:1 Explain the physiology of CO2 removal during extracorporeal support.2 Describe potential clinical applications of extracorporeal CO2 removal systems (ECCO2R) support therapy in patients with acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) as well as in those with acute kidney injury requiring renal replacement therapy.
Project description:Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides temporary cardiac and respiratory support and has emerged as an established salvage intervention for patients with hemodynamic compromise or shock. It is thereby used as a bridge to recovery, bridge to permanent ventricular assist devices, bridge to transplantation, or bridge to decision. However, weaning from VA-ECMO differs between centers, and information about standardized weaning protocols are rare. Given the high mortality of patients undergoing VA-ECMO treatment, it is all the more important to answer the many questions still remaining unresolved in this field Standardized algorithms are recommended to optimize the weaning process and determine whether the VA-ECMO can be safely removed. Successful weaning as a multifactorial process requires sufficient recovery of myocardial and end-organ function. The patient should be considered hemodynamically stable, although left ventricular function often remains impaired during and after weaning. Echocardiographic and invasive hemodynamic monitoring seem to be indispensable when evaluating biventricular recovery and in determining whether the VA-ECMO can be weaned successfully or not, whereas cardiac biomarkers may not be useful in stratifying those who will recover. This review summarizes the strategies of weaning of VA-ECMO and discusses predictors of successful and poor weaning outcome.
Project description:BackgroundAcute brain injury (ABI) remains common after extracorporeal cardiopulmonary resuscitation (ECPR). Using a large international multicenter cohort, we investigated the impact of peri-cannulation arterial oxygen (PaO2) and carbon dioxide (PaCO2) on ABI occurrence.MethodsWe retrospectively analyzed adult (≥18 years old) ECPR patients in the Extracorporeal Life Support Organization registry from 1/2009 through 12/2020. Composite ABI included ischemic stroke, intracranial hemorrhage (ICH), seizures, and brain death. The registry collects 2 blood gas data pre- (6 hours) and post- (24 hours) cannulation. Blood gas parameters were classified as: hypoxia (<60mm Hg), normoxia (60-119mm Hg), and mild (120-199mm Hg), moderate (200-299mm Hg), and severe hyperoxia (≥300mm Hg); hypocarbia (<35mm Hg), normocarbia (35-44mm Hg), mild (45-54mm Hg) and severe hypercarbia (≥55mm Hg). Missing values were handled using multiple imputation. Multivariable logistic regression analysis was used to assess the relationship of PaO2 and PaCO2 with ABI.ResultsOf 3,125 patients with ECPR intervention (median age=58, 69% male), 488 (16%) experienced ABI (7% ischemic stroke; 3% ICH). In multivariable analysis, on-ECMO moderate (aOR=1.42, 95%CI: 1.02-1.97) and severe hyperoxia (aOR=1.59, 95%CI: 1.20-2.10) were associated with composite ABI. Additionally, severe hyperoxia was associated with ischemic stroke (aOR=1.63, 95%CI: 1.11-2.40), ICH (aOR=1.92, 95%CI: 1.08-3.40), and in-hospital mortality (aOR=1.58, 95%CI: 1.21-2.06). Mild hypercarbia pre-ECMO was protective of composite ABI (aOR=0.61, 95%CI: 0.44-0.84) and ischemic stroke (aOR=0.56, 95%CI: 0.35-0.89).ConclusionsEarly severe hyperoxia (≥300mm Hg) on ECMO was a significant risk factor for ABI and mortality. Careful consideration should be given in early oxygen delivery in ECPR patients who are at risk of reperfusion injury.
Project description:Extracorporeal membrane oxygenation (ECMO) has gained renewed interest in the treatment of respiratory failure since the advent of the modern polymethylpentene membranes. Limited information exists, however, on the performance of these membranes in terms of gas transfers during multiple organ failure (MOF). We investigated determinants of oxygen and carbon dioxide transfer as well as biochemical alterations after the circulation of blood through the circuit in a pig model under ECMO support before and after induction of MOF. A predefined sequence of blood and sweep flows was tested before and after the induction of MOF with fecal peritonitis and saline lavage lung injury. In the multivariate analysis, oxygen transfer had a positive association with blood flow (slope?=?66, P<0.001) and a negative association with pre-membrane PaCO(2) (slope?=?-0.96, P?=?0.001) and SatO(2) (slope?=?-1.7, P<0.001). Carbon dioxide transfer had a positive association with blood flow (slope?=?17, P<0.001), gas flow (slope?=?33, P<0.001), pre-membrane PaCO(2) (slope?=?1.2, P<0.001) and a negative association with the hemoglobin (slope?=?-3.478, P?=?0.042). We found an increase in pH in the baseline from 7.50[7.46,7.54] to 7.60[7.55,7.65] (P<0.001), and during the MOF from 7.19[6.92,7.32] to 7.41[7.13,7.5] (P<0.001). Likewise, the PCO(2) fell in the baseline from 35 [32,39] to 25 [22,27] mmHg (P<0.001), and during the MOF from 59 [47,91] to 34 [28,45] mmHg (P<0.001). In conclusion, both oxygen and carbon dioxide transfers were significantly determined by blood flow. Oxygen transfer was modulated by the pre-membrane SatO(2) and CO(2), while carbon dioxide transfer was affected by the gas flow, pre-membrane CO(2) and hemoglobin.
Project description:In the past, the only treatment of acute exacerbations of obstructive diseases with hypercapnic respiratory failure refractory to medical treatment was invasive mechanical ventilation (IMV). Considerable technical improvements transformed extracorporeal techniques for carbon dioxide removal in an attractive option to avoid worsening respiratory failure and respiratory acidosis, and to potentially prevent or shorten the duration of IMV in patients with exacerbation of COPD and asthma. In this review, we will present a summary of the pathophysiological rationale and evidence of ECCO2R in patients with severe exacerbations of these pathologies.
Project description:BackgroundEEG-based prognostication studies in intensive care units often rely on a standard 21-electrode montage (stdEEG) requiring substantial human, technical, and financial resources. We here evaluate whether a simplified 4-frontal electrode montage (4-frontEEG) can detect EEG patterns associated with poor outcomes in adult patients under veno-arterial extracorporeal membrane oxygenation (VA-ECMO).MethodsWe conducted a reanalysis of EEG data from a prospective cohort on 118 adult patients under VA-ECMO, in whom EEG was performed on admission to intensive care. EEG patterns of interest included background rhythm, discontinuity, reactivity, and the Synek's score. They were all reassessed by an intensivist on a 4-frontEEG montage, whose analysis was then compared to an expert's interpretation made on stdEEG recordings. The main outcome measure was the degree of correlation between 4-frontEEG and stdEEG montages to identify EEG patterns of interest. The performance of the Synek scores calculated on 4-frontEEG and stdEEG montage to predict outcomes (i.e., 28-day mortality and 90-day Rankin score [Formula: see text]) was investigated in a secondary exploratory analysis.ResultsThe detection of EEG patterns using 4-frontEEG was statistically similar to that of stdEEG for background rhythm (Spearman rank test, ρ = 0.66, p < 0.001), discontinuity (Cohen's kappa, [Formula: see text] = 0.955), reactivity ([Formula: see text] = 0.739) and the Synek's score (ρ = 0.794, p < 0.001). Using the Synek classification, we found similar performances between 4-frontEEG and stdEEG montages in predicting 28-day mortality (AUC 4-frontEEG 0.71, AUC stdEEG 0.68) and for 90-day poor neurologic outcome (AUC 4-frontEEG 0.71, AUC stdEEG 0.66). An exploratory analysis confirmed that the Synek scores determined by 4 or 21 electrodes were independently associated with 28-day mortality and poor 90-day functional outcome.ConclusionIn adult patients under VA-ECMO, a simplified 4-frontal electrode EEG montage interpreted by an intensivist, detected common EEG patterns associated with poor outcomes, with a performance similar to that of a standard EEG montage interpreted by expert neurophysiologists. This simplified montage could be implemented as part of a multimodal evaluation for bedside prognostication.