Importance Information about the severity of Omicron is scarce. Objective To report the respective risk of ICU admission in patients hospitalized with Delta and Omicron variants and to compare the characteristics and disease severity of critically ill patients infected with both variants according to vaccination status. Design Analysis from the APHP database, called Reality, prospectively recording the following information in consecutive patients admitted in the ICU for COVID-19: age, sex, type of variant, immunosuppression, vaccination, pneumonia, need for invasive mechanical ventilation, time between symptom onset and ICU admission, and in-ICU mortality. Retrospective analysis on an administrative database, Systeme Information pour le Suivi des Victimes (SI-VIC), which lists hospitalized COVID-19 patients. Setting 39 hospitals in the Paris area from APHP group. Participants Patients hospitalized from December 1, 2021 to January 18, 2022 for COVID-19. Main outcomes and measures Risk of ICU admission was evaluated in 3761 patients and Omicron cases were compared to Delta cases in the ICU in 888 consecutive patients. Results On January 18, 45% of patients in the ICU and 63.8% of patients in conventional hospital units were infected with the Omicron variant (p < 0.001). The risk of ICU admission with Omicron was reduced by 64% than with Delta (9.3% versus 25.8% of cases, respectively, p < 0.001). In critically ill patients, 400 had the Delta variant, 229 the Omicron variant, 98 had an uninformative variant screening test and 161 did not have information on variant screening test. 747 patients (84.1%) were admitted for pneumonia. Compared to patients infected with Delta, Omicron patients were more vaccinated (p<0.001), even with 3 doses, more immunocompromised (p<0.001), less admitted for pneumonia (p<0.001), especially when vaccinated (62.1% in vaccinated versus 80.7% in unvaccinated, p<0.001), and less invasively ventilated (p=0.02). Similar results were found in the subgroup of pneumonia but Omicron cases were older. Unadjusted in-ICU mortality did not differ between Omicron and Delta cases, neither in the overall population (20.0% versus 27.9%, p = 0.08), nor in patients with pneumonia (31.6% versus 29.7%, respectively) where adjusted in-ICU mortality did not differ according to the variant (HR 1.43 95%CI [0.89;2.29], p=0.14). Conclusion and relevance Compared to the Delta variant, the Omicron variant is less likely to result in ICU admission and less likely to be associated with pneumonia. However, when patients with the Omicron variant are admitted for pneumonia, the severity seems similar to that of patients with the Delta variant, with more immunocompromised and vaccinated patients and no difference in adjusted in-ICU mortality. Further studies are needed to confirm our results.

Background Veno-arterial carbon dioxide tension difference (ΔPCO2) and mixed venous oxygen saturation (SvO2) have been shown to be markers of the adequacy between cardiac output and metabolic needs in critical care patients. However, they have hardly been assessed in trauma patients. We hypothesized that femoral ΔPCO2 (ΔPCO2 fem) and SvO2 (SvO2 fem) could predict the need for red blood cell (RBC) transfusion following severe trauma. Methods We conducted a prospective and observational study in a French level I trauma center. Patients admitted to the trauma room following severe trauma with an Injury Severity Score (ISS) > 15, who had arterial and venous femoral catheters inserted were included. ΔPCO2 fem, SvO2 fem and arterial blood lactate were measured over the first 24 h of admission. Their abilities to predict the transfusion of at least one pack of RBC (pRBCH6) or hemostatic procedure during the first six hours of admission were assessed using receiver operating characteristics curve. Results 59 trauma patients were included in the study. Median ISS was 26 (22–32). 28 patients (47%) received at least one pRBCH6 and 21 patients (35,6%) had a hemostatic procedure performed during the first six hours of admission. At admission, ΔPCO2 fem was 9.1 ± 6.0 mmHg, SvO2 fem 61.5 ± 21.6% and blood lactate was 2.7 ± 1.9 mmol/l. ΔPCO2 fem was significantly higher (11.6 ± 7.1 mmHg vs. 6.8 ± 3.7 mmHg, P = 0.003) and SvO2 fem was significantly lower (50 ± 23 mmHg vs. 71.8 ± 14.1 mmHg, P < 0.001) in patients who were transfused than in those who were not transfused. Best thresholds to predict pRBCH6 were 8.1 mmHg for ΔPCO2 fem and 63% for SvO2 fem. Best thresholds to predict the need for a hemostatic procedure were 5.9 mmHg for ΔPCO2 fem and 63% for SvO2 fem. Blood lactate was not predictive of pRBCH6 or the need for a hemostatic procedure. Conclusion In severe trauma patients, ΔPCO2 fem and SvO2 fem at admission were predictive for the need of RBC transfusion and hemostatic procedures during the first six hours of management while admission lactate was not. ΔPCO2 fem and SvO2 fem appear thus to be more sensitive to blood loss than blood lactate in trauma patients, which might be of importance to early assess the adequation of tissue blood flow with metabolic needs.

Background Following traumatic brain injury (TBI), coagulopathy on hospital admission is reported in 25–35% of patients and associated with increased morbimortality. The respective contributions of intracranial injury and concomitant extracranial lesions to coagulopathy have been poorly investigated. We hypothesized that the occurrence of post-TBI coagulopathy would not only be related to head injury severity, but also and to a greater extent to the presence and severity of the associated extra-cranial injuries.Methods Observational study from a multicenter prospective French trauma registry (Traumabase®). All adult patients directly admitted to one of the participating centers from January 2012 to December 2021 following TBI (AIS (Abbreviated Injury score) head ≥ 1) were included. Post-TBI coagulopathy was defined by at least 1 of the following criteria: prothrombin ratio (Quick %) < 70% or platelet count < 100 G.L− 1 or fibrinogenemia < 1.5 g.L− 1 on hospital admission. Severe associated extracranial lesions were defined by at least 1 of the extra-head AIS scores ≥ 3.Results Among 33875 patients admitted to 22 trauma centers, 9610 patients had TBI and were analyzed. The overall incidence of admission coagulopathy was 28.5%. Coagulopathic patients were significantly more severely injured and especially more severely head-injured, when compared to non-coagulopathic patients. The higher the AIShead, the higher the proportion of patients exhibiting coagulopathy (P < 0.001), whatever the presence of extracranial lesions. When compared to patients with AIShead = 1, the increased incidence of coagulopathy with TBI severity was observed at an earlier stage of TBI severity when severe extracranial lesions were present. In multivariable analysis, severe extracranial injury was independently associated with the risk of post-TBI coagulopathy (OR 2.0 (1.8–2.3), P < 0.001).Conclusions A continuously graded association between the severity of head injury and coagulopathy at hospital admission was observed, and this increased incidence of coagulopathy was observed at an earlier stage of TBI severity when severe extracranial lesions were present. The presence of severe extracranial injuries was one of the most important risk factors for coagulopathy following TBI. Intracranial and extra-cranial injury severity could be used to timely identify TBI patients most likely to present post-traumatic coagulopathy, that could benefit from early specific hemostatic resuscitation.

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