Carboxyhemoglobin predicts oxygenator performance and imminent oxygenator change in extracorporeal membrane oxygenation.

BACKGROUND: The continuous exposure of blood to a non-biological surface during extracorporeal membrane oxygenation (ECMO) may lead to progressive thrombus formation in the oxygenator, hemolysis and consequently impaired gas exchange. In most centers oxygenator performance is monitored only on a once daily basis. Carboxyhemoglobin (COHb) is generated upon red cell lysis and is routinely measured with any co-oximetry performed to surveille gas exchange and acid-base homeostasis every couple of hours. This retrospective cohort study aims to evaluate COHb in the arterial blood gas as a novel marker of oxygenator dysfunction and its predictive value for imminent oxygenator change. RESULTS: Out of the 484 screened patients on ECMO 89, cumulatively requiring 116 oxygenator changes within 1833 patient days, including 19,692 arterial COHb measurements were analyzed. Higher COHb levels were associated with lower post-oxygenator pO2 (estimate for log(COHb): - 2.176 [95% CI - 2.927, - 1.427], p < 0.0001) and with a shorter time to oxygenator change (estimate for log(COHb): - 67.895 [95% CI - 74.209, - 61.542] hours, p < 0.0001). COHb was predictive of oxygenator change within 6 h (estimate for log(COHb): 5.027 [95% CI 1.670, 15.126], p = 0.004). CONCLUSION: COHb correlates with oxygenator performance and can be predictive of imminent oxygenator change. Therefore, longitudinal measurements of COHb in clinical routine might be a cheap and more granular candidate for ECMO surveillance that should be further analyzed in a controlled prospective trial design.

[OCT, Triple H or anything else?] / OCT, Triple H oder doch etwas anderes?

Hyperammonemia is a life-threatening condition, the prognosis of which depends on a rapid reduction of ammonia. If a hepatic cause is excluded, the differential diagnosis is broad and even in adulthood includes hereditary metabolic diseases. Here, the case of a 25-year-old female patient with severe hyperammonemia refractory to standard therapy is described and the relevance of extracorporeal elimination of ammonia emphasized.

Metabolic disturbances potentially attributable to clogging during continuous renal replacement therapy.

BACKGROUND: Clogging is characterized by a progressive impairment of transmembrane patency in renal replacement devices and occurs due to obstruction of pores by unknown molecules. If citrate-based anti-coagulation is used, clogging can manifest as a metabolic alkalosis accompanied by hypernatremia and hypercalcemia, primarily a consequence of Na3Citrate infusion. An increased incidence of clogging has been observed during the COVID-19 pandemic. However, precise factors contributing to the formation remain uncertain. This investigation aimed to analyze its incidence and assessed time-varying trajectories of associated factors in critically ill patients on continuous renal replacement therapy (CRRT). METHODS: In this retrospective, single-center data analysis, we evaluated COVID-19 patients undergoing CRRT and admitted to critical care between March 2020 and December 2021. We assessed the proportional incidence of clogging surrogates in the overall population and subgroups based on the specific CRRT devices employed at our institution, including multiFiltrate (Fresenius Medical Care) and Prismaflex System (Baxter). Moderate and severe clogging were defined as Na > 145 or ≥ 150 mmol/l and HCO3- > 28.0 or ≥ 30 mmol/l, respectively, with a total albumin-corrected calcium > 2.54 mmol/l. A mixed effect model was introduced to investigate factors associated with development of clogging. RESULTS: Fifty-three patients with 240 CRRT runs were analyzed. Moderate and severe clogging occurred in 15% (8/53) and 19% (10/53) of patients, respectively. Twenty-seven percent (37/136) of CRRTs conducted with a multiFiltrate device met the criteria for clogging, whereas no clogging could be observed in patients dialyzed with the Prismaflex System. Occurrence of clogging was associated with elevated triglyceride plasma levels at filter start (p = 0.013), amount of enteral nutrition (p = 0.002) and an increasing white blood cell count over time (p = 0.002). CONCLUSIONS: Clogging seems to be a frequently observed phenomenon in critically ill COVID-19 patients. The presence of hypertriglyceridemia, combined with systemic inflammation, may facilitate the development of an impermeable secondary membrane within filters, thereby contributing to compromised membrane patency.

Older Adult Woman in a Coma After Acute Laryngitis.

CASE PRESENTATION: A 72-year-old woman with a history of adenocarcinoma of the lung, for which she was receiving tyrosine kinase inhibitor therapy with osimertinib, was admitted to the ED because of clinical deterioration with extreme fatigue and fever. She was already receiving antibiotic therapy initiated by her general practitioner because of symptoms of an upper respiratory tract infection. She was febrile (38.5 °C) with normal laboratory values except for leukocytosis and elevated C-reactive protein. She was hospitalized because of profound general malaise. On the basis of the physician's working hypothesis of severe viral laryngitis, the antibiotic therapy was stopped, and only supportive measures were taken. Over the next 3 days, her condition deteriorated, and she developed respiratory symptoms with a right-sided pleural effusion demonstrated by ultrasound examination. Over time, the patient became increasingly confused and drowsy. There was preserved urinary output and a stable glomerular filtration rate of 57 mL/min. Further on, bilirubin levels as well as coagulation were normal, indicating the absence of any relevant underlying chronic liver condition. Clinically, there were no signs of meningitis. No sedative medications that would explain her confusion were given except for low-dose opioid analgesics. On day 4 after hospitalization, she was transferred to the shock room for immediate stabilization and diagnostics because of profound encephalopathy and increasing oxygen requirements.

The Angiopoietin-2/Angiopoietin-1 ratio increases early in burn patients and predicts mortality.

BACKGROUND: Angiopoietin-2 (Angpt-2) is involved in the pathogenesis of the capillary leak syndrome in sepsis and has been shown to be associated with worse outcomes in diverse critical illnesses. It is however unclear whether Angpt-2 plays a similar role in severely burned patients during the early phase characterized by massive capillary leakage. Our aim was to analyze the Angiopoietin-2/Angiopoietin-1 ratio (Angpt-2/Angpt-1 ratio) over the first two days in critically ill burn patients and examine its association with survival and further clinical parameters. METHODS: Adult burn patients with a total burn surface area (TBSA) ≥ 20% treated in the burn intensive care unit (ICU) of the University Hospital of Zurich, Switzerland, were included. Serum samples were collected prospectively and serum Angpt-1 and Angpt-2 were measured by enzyme-linked immunosorbent assay (ELISA) over the first two days after burn insult and stratified according to survival status, TBSA and the abbreviated burn severity index (ABSI). Due to hemodilution in the initial resuscitation phase, the Angpt-2/Angpt-1 ratio was normalized to albumin. RESULTS: Fifty-six patients were included with a median age of 51.5 years. Overall mortality was 14.3% (8/56 patients). The total amount of infused crystalloids was 12́902 ml (IQR 9́362-16́770 ml) at 24 h and 18́461 ml (IQR 13́024-23́766 ml) at 48 h. The amount of substituted albumin was 20 g (IQR 10-50 g) at 24 h and 50 g (IQR 20-60 g) at 48 h. The albumin-corrected Angpt-2/Angpt-1 ratios increased over the first 48 h after the burn insult (d0: 0.5 pg*l/ml*g [IQR 0.24 - 0.80 pg*l/ml*g]; d1: 0.83 pg*l/ml*g [IQR 0.29 - 1.98 pg*l/ml*g]; d2: 1.76 pg*l/ml*g [IQR 0.70 - 3.23 pg*l/ml*g]; p < 0.001) and were significantly higher in eventual ICU non-survivors (p = 0.005), in patients with a higher TBSA (p = 0.001) and in patients with a higher ABSI (p = 0.001). CONCLUSIONS: In analogy to the pathological host response in sepsis, the Angpt-2/Angpt-1 ratio steadily increases in the first two days in critically ill burn patients, suggesting a putative involvement in the pathogenesis of capillary leakage in burns. A higher Angpt-2/Angpt-1 ratio is associated with mortality, total burn surface area and burn scores.

Donor-derived fulminant herpes simplex virus hepatitis after liver transplantation: Two cases and review of literature.

BACKGROUND: Fulminant herpetic hepatitis due to herpes simplex virus (HSV), serotype 1 or 2, is a rare but often fatal complication after solid organ transplantation (SOT). HSV hepatitis in SOT recipients can occur either due to primary infection acquired post transplantation, viral reactivation in a seropositive patient, or as donor-derived infection. Cases of fatal hepatitis have been reported in the liver as well as in other SOT recipients. The fatal outcome is mostly due to delayed diagnosis and treatment, which is explained by the lack of clinical specificity of HSV hepatitis. METHODS: We report two cases of fatal donor-derived HSV hepatitis in liver-transplanted recipients. We reviewed all published cases of donor-derived HSV infections after SOT with an evaluation of the presence of prophylaxis and outcome. RESULTS: In both liver recipients, the retrospective determination of HSV serostatus was negative, and both cases occurred in the absence of cytomegalovirus or HSV prophylaxis. A review of the literature showed a significant series of cases of severe hepatitis, mostly fatal, as well as the absence of specific preventive therapy guidelines in cases of HSV serology mismatch. CONCLUSIONS: The occurrence of two fatal donor-derived hepatitis made the Swiss Transplant Infectious Diseases working group modify its national recommendations regarding pretransplant serostatus determination and HSV prophylaxis after liver transplantation. Further studies are needed to assess this approach.

Outcomes of patients with acute respiratory failure on veno-venous extracorporeal membrane oxygenation requiring additional circulatory support by veno-venoarterial extracorporeal membrane oxygenation.

Objective: Veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) is increasingly used to support patients with severe acute respiratory distress syndrome (ARDS). In case of additional cardio-circulatory failure, some experienced centers upgrade the V-V ECMO with an additional arterial return cannula (termed V-VA ECMO). Here we analyzed short- and long-term outcome together with potential predictors of mortality. Design: Multicenter, retrospective analysis between January 2008 and September 2021. Setting: Three tertiary care ECMO centers in Germany (Hannover, Bonn) and Switzerland (Zurich). Patients: Seventy-three V-V ECMO patients with ARDS and additional acute cardio-circulatory deterioration required an upgrade to V-VA ECMO were included in this study. Measurements and main results: Fifty-three patients required an upgrade from V-V to V-VA and 20 patients were directly triple cannulated. Median (Interquartile Range) age was 49 (28-57) years and SOFA score was 14 (12-17) at V-VA ECMO upgrade. Vasoactive-inotropic score decreased from 53 (12-123) at V-VA ECMO upgrade to 9 (3-37) after 24 h of V-VA ECMO support. Weaning from V-VA and V-V ECMO was successful in 47 (64%) and 40 (55%) patients, respectively. Duration of ECMO support was 12 (6-22) days and ICU length of stay was 32 (16-46) days. Overall ICU mortality was 48% and hospital mortality 51%. Two additional patients died after hospital discharge while the remaining patients survived up to two years (with six patients being lost to follow-up). The vast majority of patients was free from higher degree persistent organ dysfunction at follow-up. A SOFA score > 14 and higher lactate concentrations at the day of V-VA upgrade were independent predictors of mortality in the multivariate regression analysis. Conclusion: In this analysis, the use of V-VA ECMO in patients with ARDS and concomitant cardiocirculatory failure was associated with a hospital survival of about 50%, and most of these patients survived up to 2 years. A SOFA score > 14 and elevated lactate levels at the day of V-VA upgrade predict unfavorable outcome.

Elimination of Herpes Simplex Virus-2 and Epstein-Barr Virus With Seraph 100 Microbind Affinity Blood Filter and Therapeutic Plasma Exchange: An Explorative Study in a Patient With Acute Liver Failure.

Herpes simplex virus (HSV)-2 is a rare cause of hepatitis that can lead to acute liver failure (ALF) and often death. The earlier the initiation of acyclovir treatment the better the survival. With regard to ALF, controlled randomized data support the use of therapeutic plasma exchange (TPE) both as bridge to recovery or transplantation-possibly by modulating the systemic inflammatory response and by replacing coagulation factors. Seraph 100 Microbind Affinity Blood Filter (Seraph; Ex Thera Medical, Martinez, CA), a novel extracorporeal adsorption device, removes living pathogens by binding to a heparin-coated surface was shown to efficiently clear HSV-2 particles in vitro. Here, we tested the combination of Seraph with TPE to reduce a massive HSV-2 viral load to reach a situation in that liver transplantation would be feasible. DESIGN: Explorative study. SETTING: Academic tertiary care transplant center. PATIENT: Single patient with HSV-2-induced ALF. INTERVENTIONS: TPE + Seraph 100 Microbind Affinity Blood Filter. MEASUREMENTS AND MAIN RESULTS: We report Seraph clearance data of HSV-2 and of Epstein-Barr virus (EBV) in vivo as well as total viral elimination by TPE. Genome copies/mL of HSV-2 and EBV in EDTA plasma were measured by polymerase chain reaction every 60 minutes over 6 hours after starting Seraph both systemically and post adsorber. Also, HSV-2 and EBV were quantified before and after TPE and in the removed apheresis plasma. We found a total elimination of 1.81 × e11 HSV-2 copies and 2.11 × e6 EBV copies with a single TPE (exchange volume of 5L; 1.5× calculated plasma volume). Whole blood clearance of HSV-2 in the first 6 hours of treatment was 6.64 mL/min (4.98-12.92 mL/min). Despite much lower baseline viremia, clearance of EBV was higher 36.62 mL/min (22.67-53.48 mL/min). CONCLUSIONS: TPE was able to remove circulating HSV-2 copies by 25% and EBV copies by 40% from the blood. On the other hand, clearance of HSV-2 by Seraph was clinically irrelevant, but Seraph seemed to be far more effective of removing EBV, implicating a possible use in EBV-associated pathologies, but this requires further study.

Renal Tubular Acidosis in Pregnant Critically Ill COVID-19 Patients: A Secondary Analysis of a Prospective Cohort.

BACKGROUND: Renal tubular acidosis (RTA) is an extremely rare cause of metabolic acidosis (10 in 100,000). RTA has been linked neither to pregnancy nor to severe coronavirus disease 2019 (COVID-19). The purpose of this study was to analyze the prevalence and clinical course of normal anion gap metabolic acidosis in critically ill pregnant COVID-19 patients and to compare them to an age-matched nonpregnant female patient cohort. METHODS: Secondary analysis was conducted on a prospective observational cohort of critically ill patients suffering from COVID-19 consecutively admitted to a tertiary intensive care unit (ICU) between February 2020 and April 2021. RESULTS: A total of 321 COVID-19 patients required admission to the ICU; 95 (30%) were female, and 18 (19%) were of childbearing age. Seven of eight (88%) pregnant women (all in the last trimester) required advanced respiratory support due to COVID-19. The estimated glomerular filtration rate was 135 (123-158) mL/min/m2 body surface area, and six pregnant women (86%) were diagnosed with a normal, respiratory compensated, anion gap metabolic acidosis (pHmin 7.3 (7.18-7.31), HCO3-min 14.8 (12.8-18.6) mmol/L, and paCO2 3.4 (3.3-4.5) kPa). Three (43%) acidotic pregnant women fulfilled diagnostic criteria for RTA. All women recovered spontaneously within less 7 days. CONCLUSIONS: Metabolic acidosis seems to be very common (85%) in pregnant critically ill COVID-19 patients, and the prevalence of RTA might be higher than normal. It remains to be demonstrated if this observation is an indirect epiphenomenon or due to a direct viral effect on the tubular epithelium.

Long-term ketamine infusion-induced cholestatic liver injury in COVID-19-associated acute respiratory distress syndrome.

BACKGROUND: A higher-than-usual resistance to standard sedation regimens in COVID-19 patients suffering from acute respiratory distress syndrome (ARDS) has led to the frequent use of the second-line anaesthetic agent ketamine. Simultaneously, an increased incidence of cholangiopathies in mechanically ventilated patients receiving prolonged infusion of high-dose ketamine has been noted. Therefore, the objective of this study was to investigate a potential dose-response relationship between ketamine and bilirubin levels. METHODS: Post hoc analysis of a prospective observational cohort of patients suffering from COVID-19-associated ARDS between March 2020 and August 2021. A time-varying, multivariable adjusted, cumulative weighted exposure mixed-effects model was employed to analyse the exposure-effect relationship between ketamine infusion and total bilirubin levels. RESULTS: Two-hundred forty-three critically ill patients were included into the analysis. Ketamine was infused to 170 (70%) patients at a rate of 1.4 [0.9-2.0] mg/kg/h for 9 [4-18] days. The mixed-effects model revealed a positively correlated infusion duration-effect as well as dose-effect relationship between ketamine infusion and rising bilirubin levels (p < 0.0001). In comparison, long-term infusion of propofol and sufentanil, even at high doses, was not associated with increasing bilirubin levels (p = 0.421, p = 0.258). Patients having received ketamine infusion had a multivariable adjusted competing risk hazard of developing a cholestatic liver injury during their ICU stay of 3.2 [95% confidence interval, 1.3-7.8] (p = 0.01). CONCLUSIONS: A causally plausible, dose-effect relationship between long-term infusion of ketamine and rising total bilirubin levels, as well as an augmented, ketamine-associated, hazard of cholestatic liver injury in critically ill COVID-19 patients could be shown. High-dose ketamine should be refrained from whenever possible for the long-term analgosedation of mechanically ventilated COVID-19 patients.