Publications

Introduction: Hyperoxia and hypocapnia have been associated with poor outcome after cardiac arrest (CA). However, definitions of hyperoxia and hypocapnia were based on a limited number of blood gas analyses per patient. Also, no data are available on the combined effects of altered arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) on outcome. Methods: We reviewed all comatose patients admitted after successful resuscitation from CA to a single academic medical center between January 2007 and April 2013. Inclusion criteria were as follows: age ≥18, non-traumatic arrest; and survival ≥24 hours after admission. We analyzed all arterial blood gas data for the first 24 hours after hospital admission. We a priori defined hypocapnia and hypercapnia as at least one PaCO2 ≤30 mmHg and ≥50 mmHg, respectively; we a priori defined hypoxemia and hyperoxemia as at least one PaO2 ≤60 mmHg and ≥300 mmHg, respectively. A CPC score of 3-5 at 3-months was used to define poor neurological outcome. Results: Of 207 patients, 78 (37%) had hypocapnia only, 46 (22%) had hypercapnia only, 42 (20%) had hypocapnia and hypercapnia and 41 (20%) had neither; 78 (23%) patients had hypoxemia only, 44 (21%) had hyperoxemia only, 7 (3%) had hypoxemia and hyperoxemia and 109 (53%) had neither (p<0.001). The median number of blood gas analyses was 10 [8-12] per patient. Among the patients, 139 (67%) had a poor neurological outcome. Patients with hypocapnia and hypercapnia had similar rates of poor neurological outcome (73% and 59%) than those without or with both PaCO2 abnormalities (69% and 64%, p=0.42). Patients with hypoxemia and hyperoxemia also had similar rates of poor neurological outcome (70% and 70%) than those without or with both PaO2 abnormalities (72% and 85%, p=0.85). In patients with hypocapnia and hypercapnia mortality was higher if concomitant hypoxemia or hyperoxemia were present (6/8 and 6/6, respectively) compared to patients without PaO2 abnormalities (12/24; p=0.05). Conclusions: In this retrospective study, PaCO2 abnormalities were more frequent than PaO2 alterations after CA. PaO2 and PaCO2 abnormalities were not associated with poor outcome. Hypoxemia and hyperoxemia increased the risk for poor outcome only among those patients concomitantly exposed to large variations in PaCO2.

Abstract Abstract 4729 Sepsis and its sequelae remain leading causes of death in critically ill patients. Early identification and subsequently prompt treatment of sepsis can have a major impact on the outcome of septic patients. White Blood Cell (WBC) count, neutrophils count or percentage and percentage of band and immature neutrophils have been included in the diagnostic criteria of sepsis d. Previous studies have shown that morphological changes of leukocytes during sepsis can be quantified using Volume, Conductivity and Scatter (VCS) technology by some hematology analyzers. DxH800 (Beckman Coulter, Fullerton, CA) has the potential to report, in addition to Volume and Conductivity, five extra-laser diffraction angles for each cellular event. The aim of the study was to evaluate the diagnostic accuracy of VCS parameters of leukocytes in detecting sepsis in critically ill adult patients. This prospective observational study involved all consecutive adult patients admitted to a 31-bed medico-surgical department of intensive care (ICU) for more than 4 hours in a 3.5-month period. Diagnosis of sepsis was based on standard definitions. Blood samples were run by DxH800. Complete blood count (CBC) and WBC differential, but not VCS parameters were reported to attending physicians. Of a total of 722 patients admitted during the observation period 422 had WBC differential (and thus VCS parameters) determined at admission, of whom 125 had sepsis Septic and non-septic patients had a median age (upper and lower quartile) of 60 (51-71) and 58 (45-72) years and APACHE II scores of 19 (14-25) and 11 (7-16). VCS parameters had higher Areas Under the Receiver Operating Characteristic Curve (AUC) than WBC or percentage of neutrophils for diagnosis of sepsis at admission (Table 1.).Table 1.DxH800 VCS parameters. Results as median values (upper and lower quartile)VCS parametersSepsis N=125No Sepsis N=317p valueAUC95%CI of AUCMean Volume of Neutrophils (MNVNE)153 (146–163)144 (140–148)&lt;0.0010.780.72–0.83SD of Volume of Neutrophils (SDVNE)20 (18–23)17 (16–18)&lt;0.0010.810.77–0.86Mean Axial Light loss of Neutrophils (MNAL2NE)155 (150–160)148 (144–151)&lt;0.0010.780.73–0.84SD of Axial Light loss of Neutrophils (SDAL2NE)13 (12–16)11 (10–12)&lt;0.0010.800.75–0.84Mean Volume of Monocytes (MNVMO)179 (169–189)163 (159–167)&lt;0.0010.880.84–0.91SD of Volume of Monocytes (SDVMO)24 (21–28)18 (16–20)&lt;0.0010.880.84–0.91SD of Axial Light loss of Monocytes (SDAL2MO)16 (15–20)13 (12–14)&lt;0.0010.850.81–0.89WBC, 103/ml10.9 (7.3–15.3)10.5 (7.8–14.2)NS0.510.44–0.57Percent of Neutrophils, %85 (76–91)80 (68–88)&lt;0.0010.610.55–0.67 On ICU admission, MNVMO had the highest discriminant values in detecting sepsis with sensitivity (Se) of 84%, specificity (Sp) 76%, positive predictive value (PPV)58%, negative predictive value (NPV) 92% and odds ratio (OR) 17 for a cutoff of 168. MNVMO&lt;168 (59% of patients) gave reasonable evidence against sepsis (likelihood ratio (LR) of 0.21, pre- and post-test probability, 0.28 and 0.076,) and MNVMO≥175 (25% of patients) gave reasonable evidence for sepsis (LR of 6.85, pre- and post-test probability, 0.28 and 0.73, respectively). Only 16% of patients, in the intermediate range, had a rather uninformative test result (LR of 1.32). Combining monocyte or neutrophil VCS parameters with CRP slightly increases AUC to 0.91. During the ICU stay, VCS parameters were obtained in 316 initially non-septic patients, of whom 20 became septic. MNVMO &lt; 174 excluded ICU-acquired infection with NPV of 99% and MNVMO &gt; 174 predicted ICU-acquired infection 1.7 days earlier than clinical diagnosis (Se: 85%, Sp 68%, OR 12 and AUC=0.78, 95% CI: 66–90). CONCLUSIONS: This large prospective study in unselected critically ill adult patients demonstrates the diagnostic utility of VCS parameters, especially MNVMO, in detecting and, more importantly, excluding sepsis at admission and during ICU stay. VCS parameters are obtained automatically, routinely, within minutes, requiring neither additional sampling nor additional cost to that of complete blood count thus making their prospects very promising. Disclosures: Pradier: Beckman Coulter: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Microcirculatory reactivity is decreased in patients with circulatory shock and has prognostic value. This simple, noninvasive test could help in monitoring the peripheral microcirculation in acutely ill patients.

The hemodynamic response to controlled oxygen administration was investigated in 35 patients who presented with acute decompensation of chronic obstructive pulmonary disease. Gasometric and hemodynamic data were successively measured under inspiratory fractions in oxygen of 0.21 (room air) and 0.28. Response to oxygen therapy was characterized by a decrease in cardiac output and an increase in oxygen delivery because of a sharp increase in arterial oxygen content. The coefficient of oxygen delivery (oxygen delivery/oxygen consumption) increased in each patient. All these changes were highly significant (p < 0.001). Somewhat unexpectedly, there was no change in pulmonary artery pressures, so that pulmonary arteriolar resistance even increased (p < 0.05). Further analysis individualized 2 types of hemodynamic response to oxygen therapy. In 15 patients who presented with severe hypoxemia, oxygen therapy resulted in a significant increase in oxygen delivery without change in cardiac output. By contrast, in 20...