Introduction: Extracorporeal membrane oxygenation (ECMO) is used in critically ill patients presenting acute cardiac and/or pulmonary dysfunctions, who are at high risk of developing acute kidney injury and fluid overload. Continuous renal replacement therapy (CRRT) is commonly used in intensive care units (ICU) to provide renal replacement and fluid management. We conducted a review to assess the feasibility, efficacy and safety of the combination of ECMO and CRRT and to illustrate the indications and methodology of providing renal replacement therapy during the ECMO procedure. Method: We searched for all published reports of a randomized controlled trial (RCT), quasi-RCT, or other comparative study design, conducted in patients undergoing ECMO plus CRRT. Two reviewers independently selected potential studies and extracted data. We used the modified Jadad scale and the Newcastle-Ottawa for quality assessment of RCTs and non-RCTs, respectively. Statistical analyses were performed using RevMan 5.2. Results: We identified 19 studies meeting the eligibility criteria (seven cohort, six case control, one historically controlled trial and five studies of technical aspects). There are three major methods for performing CRRT during ECMO: ‘independent CRRT access’, ‘introduction of a hemofiltration filter into the ECMO circuit (in-line hemofilter)’ and ‘introduction of a CRRT device into the ECMO circuit’. We conducted a review with limited data synthesis rather than a formal meta-analysis because there could be greater heterogeneity in a systematic review of non-randomized studies than that of randomized trials. For ECMO survivors receiving CRRT, overall fluid balance was less than that in non-CRRT survivors. There was a higher mortality and a longer ECMO duration when CRRT was added, which may reflect a relatively higher severity of illness in patients who received ECMO plus CRRT. Conclusions: The combination of ECMO and CRRT in a variety of methods appears to be a safe and effective technique that improves fluid balance and electrolyte disturbances. Prospective studies would be beneficial in determining the potential of this technique to improve the outcome in critically ill patients.

Measurement of optic nerve sheath diameter (ONSD) is a fast and non-invasive method in detecting elevated intracranial pressure. However, the reported normal range of ONSD was inconsistent. The objective of the study was to determine the normal range of ONSD in healthy Chinese adults. Eyeball transverse diameter (ETD), optic nerve diameter (OND), and ONSD were measured by ultrasound examination in healthy adult volunteers. The OND and ONSD were assessed 3 mm behind the globe. The section showing maximal transverse diameter of the eyeball was frozen and the diameter was measured. Each ETD, OND and ONSD was examined twice and the mean value was calculated. A total of 519 healthy volunteers were included in the study. The median (interquartile range) of ETD, OND and ONSD were 22.3 (21.6 to 23.1) mm, 3.2 (2.9 to 3.4) mm, and 5.1 (4.7 to 5.4) mm, respectively. The 95 % percentile of ONSD was 5.9 mm. There was no significant difference in ETD, OND or ONSD between male and female, or between left and right eye. ONSD was significantly correlated with OND (r = 0.62, P < 0.001), and the median OND/ONSD ratio (interquartile range) was 0.63 (0.59 to 0.67). The median and the 95 % percentile of sonographic measurement of ONSD are 5.1 mm and 5.9 mm in healthy Chinese adults. The ONSD is correlated with OND, while independent of gender, age, height, weight and ETD. The median OND/ONSD ratio is 0.63 and this parameter warrants further investigation in patients with brain injury.

Background: An index of dynamic lactate change that incorporates both the magnitude of change and the time interval of such change, termed “normalized lactate load,” may reflect the hypoxic burden of septic shock. We aimed to evaluate the association between normalized lactate load and 28-day mortality in adult septic shock patients. Methods: Patients with septic shock were identified from the Medical Information Mart for Intensive Care (MIMIC)-III database. Lactate load was defined as the sum of the area under the curve (AUC) of serial lactate levels using the trapezoidal rule, and normalized lactate load was defined as the lactate load divided by time. Receiver-operating characteristic curves were constructed to determine the performance of initial lactate, maximum lactate and normalized lactate load in predicting 28-day mortality. Results: A total of 1371 septic shock patients were included, and the 28-day mortality was 39.8%. Non-survivors had significantly higher initial lactate (means ± standard deviations: 3.9 ± 2.9 vs. 2.8 ± 1.7 mmol/L), maximum lactate (5.8 ± 3.8 vs. 4.3 ± 2.2 mmol/L), lactate load (94.3 ± 71.8 vs. 61.1 ± 36.4 mmol·hr./L) and normalized lactate load (3.9 ± 3.0 vs. 2.5 ± 1.5 mmol/L, all p < 0.001). The AUCs of initial lactate, maximum lactate and normalized lactate load were 0.623 (95% confidence interval: 0.596–0.648, with a cut-off value of 4.4 mmol/L), 0.606 (0.580–0.632, with a cut-off value of 2.6 mmol/L) and 0.681 (0.656–0.706, with a cut-off value of 2.6 mmol/L), respectively. The AUC of normalized lactate load was significantly greater than both initial lactate and maximum lactate (all p < 0.001). In the multivariate logistic regression model, normalized lactate load was identified as an independent risk factor for 28-day mortality. Conclusions: Normalized lactate load is an independent risk factor for 28-day mortality in adult septic shock patients. Normalized lactate load had better accuracy than both initial and maximum lactate in determining the prognosis of septic shock patients.

Respiratory system elastance (ERS) is an important determinant of the responsiveness of intracranial pressure (ICP) to positive end-expiratory pressure (PEEP). However, lung elastance (EL) and chest wall elastance (ECW) were not differentiated in previous studies. We tested the hypothesis that patients with high ECW or a high ECW/ERS ratio have greater ICP responsiveness to PEEP. An esophageal balloon catheter was placed to measure esophageal pressure. PEEP was increased from 5 to 15 cmH2O. Airway pressure and esophageal pressure were measured and EL, ECW and ERS were calculated at the two PEEP levels. Patients were classified into either an ICP responder group or a non-responder group based on whether the change of ICP after PEEP adjustment was greater than or less than the median of the overall study population. The magnitude of the increase in esophageal pressure (median [interquartile range]) at end-expiratory occlusion was significantly increased in the responder group compared with that in the non-responder group (4.1 [2.7–4.1] versus 2.7 [0.0–2.7] cmH2O, p = 0.033) after PEEP adjustment. ECW and the ECW/ERS ratio were significantly higher in ICP responders than in non-responders at both low PEEP (p = 0.021 and 0.017) and high PEEP (p = 0.011 and 0.025) levels. No significant differences in ERS and EL were noted between the two groups at both PEEP levels. Patients with greater ICP responsiveness to increased PEEP exhibit higher ECW and a higher ECW/ERS ratio, suggesting the importance of ECW monitoring.

Background: The present study aimed to evaluate the association between normalized lactate load, an index that incorporates the magnitude of change and the time interval of such evolution of lactate, and 28-day mortality in sepsis and non-sepsis patients. We also compared the accuracy of normalized lactate load in predicting mortality between these two populations. Methods: Data were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database. We defined lactate load as the sum of the area under the lactate concentration curve; we also defined normalized lactate load as the lactate load divided by time. The performance of maximum lactate, mean lactate and normalized lactate load in predicting 28-day mortality in sepsis and non-sepsis patients were compared by receiver-operating characteristic curves analysis. Results: A total of 21,333 patients were included (4219 sepsis and 17,114 non-sepsis patients). Non-survivors had significantly higher normalized lactate load than survivors in sepsis and non-sepsis patients. The maximum lactate, mean lactate, and normalized lactate load AUCs were significantly greater in sepsis patients than in non-sepsis patients. Normalized lactate load had the greatest AUCs in predicting 28-day mortality in both sepsis and non-sepsis patients. Sensitivity analysis showed that the AUC of normalized lactate load increased in non-sepsis patients when more lactate measurement was obtained, but it was not improved in sepsis patients. Conclusions: Normalized lactate load has the strongest predictive power compared with maximum or mean lactate in both sepsis and non-sepsis patients. The accuracy of normalized lactate load in predicting mortality is better in sepsis patients than in non-sepsis patients.

Background: Inflammatory response is activated during cardiopulmonary bypass (CPB), which may lead to acute respiratory distress syndrome (ARDS) and procalcitonin (PCT) increases during this inflammatory response. The objective of the study was to validate whether patients with higher serum PCT concentrations have a higher incidence of ARDS.Methods: The study was a prospective, single-center, observational cohort study. All patients who received cardiac surgery with CPB were screened for study eligibility. Patients were assigned to the PCT-elevated cohort or the control cohort according to serum PCT concentration on the first postoperative day with a cut-off value of 7.0 ng/mL. Patients were followed up until the 7th postoperative day. The primary endpoint was the incidence of ARDS, which was diagnosed according to the Berlin definition.Results: A total of 296 patients were enrolled, 64 patients were assigned to the PCT-elevated cohort and 232 patients were assigned to the control cohort. PCT concentration was 16.23 ± 5.9 ng/mL in the PCT-elevated cohort, and 2.70 ± 1.43 ng/mL in the control cohort (p < 0.001). The incidence of ARDS was significantly higher in the PCT-elevated cohort than in the control cohort (21.9% versus 5.6%,p < 0.001). The incidence of moderate-to-severe ARDS was also significantly higher in the PCT-elevated cohort than in the control cohort (10.9% versus 0.4%,p < 0.001). The hazard ratio of ARDS at 7 days in the PCT-elevated cohort, as compared with the control cohort, was 6.8 (95% confidence interval 2.7 to 17.4). The hazard ratio of moderate-to-severe ARDS in the PCT-elevated cohort was 57.3 (95% confidence interval 10.4 to 316.3). The positive predictive value of PCT for ARDS and moderate-to-severe ARDS were 0.242 and 0.121, respectively; the negative predictive value of PCT for ARDS and moderate-to-severe ARDS were 0.952 and 1.0, respectively.Conclusion: Cardiac surgical patients with elevated PCT concentration have a higher incidence of ARDS. Elevated PCT may serve as a warning signal of postoperative ARDS in patients undergoing cardiac surgery with CPB.Study registrationChinese Clinical Trial Registry (ChiCTR-OCH-14005076)