Central Venous Oxygen Research Articles

Early warning: End-tidal carbon dioxide is associated with central venous oxygenation under continuous cardiorespiratory monitoring in a porcine model of hemorrhagic shock and resuscitation

BackgroundEnd-tidal carbon dioxide (ETCO2) has previously shown promise as a predictor of shock severity and mortality in trauma. ETCO2 monitoring is non-invasive, real-time, and readily available in prehospital settings, but the temporal relationship of ETCO2 to systemic oxygen transport has not been thoroughly investigated in the context of hemorrhagic shock. MethodsA validated porcine model of hemorrhagic shock and resuscitation was used in male Yorkshire swine (N ​= ​7). Both ETCO2 and central venous oxygenation (SCVO2) were monitored and recorded continuously in addition to other traditional hemodynamic variables. ResultsLinear regression analysis showed that ETCO2 was associated with ScvO2 both throughout the experiment (β ​= ​1.783, 95% confidence interval (CI) [1.552–2.014], p ​< ​0.001) and during the period of most rapid hemorrhage (β ​= ​4.896, 95% CI [2.416–7.377], p ​< ​0.001) when there was a marked decrease in ETCO2. ConclusionsETCO2 and ScvO2 were closely associated during rapid hemorrhage and continued to be temporally associated throughout shock and resuscitation.

#4606 INNOVATIVE METHOD TO EVALUATE MATURATION OF NEWLY CREATED ARTERIO-VENOUS FISTULAS: INSIGHTS FROM A QUALITY IMPROVEMENT PROJECT

Abstract Background and Aims Recently, we introduced central-venous oxygen saturation (ScvO2) and estimated upper-body blood flow (eUBBF) to monitor the maturation of newly created arterio-venous fistulas (AVF) in hemodialysis (HD) patients [1]. The approach was implemented in a clinical quality improvement project (QIP). Method The QIP involved two Renal Research Institute dialysis centers in New York City that use the Crit-Line monitor (CLM, Fresenius Medical Care, Waltham, MA, USA) as part of the standard of care. CLM measures automatically and non-invasively hematocrit and oxygen saturation (i.e., ScvO2 in patients with central venous catheter as vascular access). eUBBF was computed as described previously [1]. Patients with a with a newly created AVF were included, irrespective of their HD vintage. The QIP team comprised a registered nurse per clinic, two research physicians, and two data analysts. The team met weekly to assess the AVF maturation progress based on eUBBF and ScvO2 data that were displayed on a specific dashboard. Successful AVF maturation is typically accompanied by a rise in cardiac output and eUBBF that starts immediately after AVF creation. However, it is unknown what degree of eUBBF increase indicates a subsequently successful AVF maturation. To identify predictive eUBBF thresholds, we correlated eUBBF changes with the progress of AVF maturation in the six weeks following AVF creation. We defined maturation as unsuccessful when the newly created AVF required an intervention (e.g., angioplasty) or was abandoned. Results We studied 39 patients (age 56 ±18 years; 25 males). Twenty-eight of them were incident patients. Two patients had a second AVF created. In 15 patients AVF maturation was unsuccessful. In these patients, eUBBF increased to an average of 119.2% (SD 35.2) compared to pre-AFV creation. In patients with successful AFV maturation (N = 24), eUBBF increased to an average of 153.7% (SD 31.6) (Figure 1). The difference between the groups is 34.4 percentage points (95% CI: 12.4 to 56.4; p = 0.003). Using eUBBF as a diagnostic measure to discriminate successful vs. failed AVF maturation, an area under the receiver operating characteristics curve of 0.824 (95% CI: 0.673 to 0.925; p&amp;lt;0.0001) was obtained. An eUBBF increase of 25% had a sensitivity of 59% and a specificity of 92% to predict AVF maturation outcomes. Conclusion Computation of eUBBF provides a simple and non-invasive means to track AVF maturation and predict its outcomes.

Venous-arterial CO2 to arterial-venous O2 content ratio in different shock types and correlation with hypoxia indicators.

Shock is a generalized form of acute circulatory failure characterized by low tissue perfusion. If not recognized early, it highly increases patient morbidity and mortality. Central venous-arterial CO2 (Carbon dioxide) to arterial-central venous O2 (Oxygen) content ratio (Pcv-aCO2/Ca-cvO2) has been used for the early prediction of anaerobic metabolism in septic shock patients. However, knowledge about the usability of this ratio in cardiogenic shock is scarce. We retrospectively collected the data of patients admitted to our 18-bed intensive care unit (Haga Hospital, Department of Intensive Care, The Hague, The Netherlands) with a diagnosis of septic shock or cardiogenic shock in 2018. All patients who had undergone Swan-Ganz or Pulse index Continuous Cardiac Output device insertion were included in the study. The hemodynamic variables were recorded both at ICU admission and during catheterization. Forty-six (n= 46) patients with a mean age of 62 ± 13 years and 52% female gender were enrolled in the study. The Acute Physiology and Chronic Health Evaluation IV (APACHE IV) score was 96 ± 39. Twenty-four patients had septic shock, and twenty-two were diagnosed with cardiogenic shock. Although Pcv-aCO2 (Central venous-arterial CO2) and ScvO2 (Central venous oxygen) were not found different between the cardiogenic and septic shock groups, the Pcv-aCO2/Ca-cvO2 ratio was significantly lower in patients with cardiogenic shock (p= 0.035). The Pcv-aCO2/Ca-cvO2 ratio had a weak correlation with ScvO2 (r= 0.21, p= 0.040). Pcv-aCO2 and ScvO2 showed negative lower moderate correlation (r= -0.40, p= 0.030). Twenty patients [nine (19%) with cardiogenic shock, and eleven (23%) with septic shock] died during their ICU or hospital stay. Although Ca-cvO2, Pcv-aCO2, and ScvO2 were not associated with mortality, a higher Pcv-aCO2/Ca-cvO2 ratio was associated with increased mortality (p= 0.035). The Pcv-aCO2/Ca-cvO2 ratio is a valuable hypoxia indicator in states of shock. However, cutoff levels should be identified for different shock types.

Correlation of central venous-to-arterial carbon dioxide difference to arterial-central venous oxygen difference ratio to lactate clearance and prognosis in patients with septic shock: A prospective observational cohort study.

To assess the relationship between the ratio of difference of venoarterial CO2 tension (P (v-a) CO2) and difference of arterio-venous oxygen content (C (a-cv) O2), i.e., ΔPCO2/ΔCaO2 with lactate clearance (LC) at 8 and 24 h, to define a cutoff for the ratio to identify LC >10% and >20% at 8 and 24 h, respectively, and its association with prognosis in septic shock. Adult patients with septic shock were included in this prospective, observational cohort study. Blood samples for arterial lactate, arterial, and central venous oxygen and carbon dioxide were drawn simultaneously at time zero (T0), 8 h (T8), and 24 h (T24). At T8, patients were divided into Group 8A (LC ≥10%) and Group 8B (LC <10%). At T24, patients were divided into Group 24A (LC ≥20%) and Group 24B (LC <20%). Ninty-eight patients were included. The area under the curve of ΔPCO2/ΔCaO2 at T8 (0.596) and T24 (0.823) was the highest when compared to P(v-a) CO2 and C(a-v) O2. The best cutoff of P(v-a) CO2/C (a-v) O2 as predictor of LC >10% was 1.31 (sensitivity 70.6% and specificity 53.3%) and for LC >20% was 1.37 (sensitivity 100% and specificity 50%). At both T8 and T24, P(v-a) CO2/C (a-v) O2 showed a significant negative correlation with LC. Groups 8A and 24A showed lower intensive care unit mortality than 8B and 24B, respectively. Values of P(v-a) CO2/C (a-v) O2 at T8 were comparable, but at T24, there was a significant difference between the survivors and nonsurvivors (P < 0.001). ΔPCO2/ΔCaO2 predicts lactate clearance, and its 24 h value appears superior to the 8-h value in predicting LC and mortality in septic shock patients.

Physiologic effects of stress dose corticosteroids in in-hospital cardiac arrest (CORTICA): A randomized clinical trial

AimPostresuscitation hemodynamics are associated with hospital mortality/functional outcome. We sought to determine whether low-dose steroids started during and continued after cardiopulmonary resuscitation (CPR) affect postresuscitation hemodynamics and other physiological variables in vasopressor-requiring, in-hospital cardiac arrest. MethodsWe conducted a two-center, randomized, double-blind trial of patients with adrenaline (epinephrine)-requiring cardiac arrest. Patients were randomized to receive either methylprednisolone 40 mg (steroids group) or normal saline-placebo (control group) during the first CPR cycle post-enrollment. Postresuscitation shock was treated with hydrocortisone 240 mg daily for 7 days maximum and gradual taper (steroids group), or saline-placebo (control group). Primary outcomes were arterial pressure and central-venous oxygen saturation (ScvO2) within 72 hours post-ROSC. ResultsEighty nine of 98 controls and 80 of 86 steroids group patients with ROSC were treated as randomized. Primary outcome data were collected from 100 patients with ROSC (control, n = 54; steroids, n = 46). In intention-to-treat mixed-model analyses, there was no significant effect of group on arterial pressure, marginal mean (95% confidence interval) for mean arterial pressure, steroids vs. control: 74 (68–80) vs. 72 (66–79) mmHg] and ScvO2 [71 (68–75)% vs. 69 (65–73)%], cardiac index [2.8 (2.5–3.1) vs. 2.9 (2.5–3.2) L/min/m2], and serum cytokine concentrations [e.g. interleukin-6, 89.1 (42.8–133.9) vs. 75.7 (52.1–152.3) pg/mL] determined within 72 hours post-ROSC (P = 0.12–0.86). There was no between-group difference in body temperature, echocardiographic variables, prefrontal blood flow index/cerebral autoregulation, organ failure-free days, and hazard for poor in-hospital/functional outcome, and adverse events (P = 0.08–>0.99). ConclusionsOur results do not support the use of low-dose corticosteroids in in-hospital cardiac arrest.Trial Registration:ClinicalTrials.gov number: NCT02790788 (https://www.clinicaltrials.gov).

MO786: Monitoring of Arterio-Venous Fistula Maturation using Central-Venous Oxygen Saturation and Estimated Upper-Body Blood Flow: Impact on Catheter Residence Time

Abstract BACKGROUND AND AIMS In hemodialysis patients, assessment of arterio-venous fistula (AVF) maturation is key to reduce the residence time of central venous catheters (CVC). We have introduced the use of central-venous oxygen saturation (ScvO2) and estimated upper-body blood flow (eUBBF) as means to monitor AVF maturation [1]. We now report CVC residence time in patients with and without ScvO2-based AVF maturation monitoring. METHOD We studied hemodialysis patients in who ScvO2-based AVF maturation monitoring was implemented within the framework of a clinical quality improvement project (QIP). ScvO2 and hematocrit were measured with Crit-Line (Fresenius Medical Care, Waltham, MA). eUBBF was computed as described previously [1]. We used time-to-event analysis to compare the CVC residence time post-AVF creation between patients who participated in the QIP (intervention group) and non-QIP patients (control group). Both groups were dialyzed in the same geography. Patients were censored at the time of death, change of dialytic modality, transplantation, lost to follow up, recovery of kidney function and end of the observation period (15 November 2021). RESULTS The intervention group comprised 44 patients [age 57 ± 17 years; 27 (61%) males]. In five patients, two AVF were created; in 34 (69%) CVC were removed. The control group comprised of 378 patients (age 59 ± 15 years, 61% males). CVC was removed in 199 (53%) control patients. In the intervention group, CVC were removed 125 days [95% confidence interval (95% CI): 102–171] after AVF creation. In the control group, this time was 236 days (95% CI: 173–404) (P &amp;lt; 0.0003; log rank test; Figure). CONCLUSION Compared to controls, the CVC residence time post AVF-creation was shortened significantly— by about 3.6 months—in patients who participated in a QIP that used ScvO2-baseed assessment of AVF maturation. Measurement of ScvO2 and computation of eUBBF are simple, non-invasive means to track AVF maturation, trigger timely interventions and AVF cannulation and shorten CVC residence time.

Can central-venous oxygen saturation be estimated from tissue oxygen saturation during a venous occlusion test?

ObjectiveTo test whether tissue oxygen saturation (StO2) after a venous occlusion test estimates central venous oxygen saturation (ScvO2).MethodsObservational study in intensive care unit patients. Tissue oxygen saturation was monitored (InSpectra Tissue Spectrometer Model 650, Hutchinson Technology Inc., MN, USA) with a multiprobe (15/25mm) in the thenar position. A venous occlusion test in volunteers was applied in the upper arm to test the tolerability and pattern of StO2 changes during the venous occlusion test. A sphygmomanometer cuff was inflated to a pressure 30mmHg above diastolic pressure until StO2 reached a plateau and deflated to 0mmHg. Tissue oxygen saturation parameters were divided into resting StO2 (r-StO2) and minimal StO2 (m-StO2) at the end of the venous occlusion test. In patients, the cuff was inflated to a pressure 30mmHg above diastolic pressure for 5 min (volunteers’ time derived) or until a StO2 plateau was reached. Tissue oxygen saturation parameters were divided into r-StO2, m-StO2, and the mean time that StO2 reached ScvO2. The StO2 value at the mean time was compared to ScvO2.ResultsAll 9 volunteers tolerated the venous occlusion test. The time for tolerability or the StO2 plateau was 7 ± 1 minutes. We studied 22 patients. The mean time for StO2 equalized ScvO2 was 100 sec and 95 sec (15/25mm probes). The StO2 value at 100 sec ([100-StO2] 15mm: 74 ± 7%; 25mm: 74 ± 6%) was then compared with ScvO2 (75 ± 6%). The StO2 value at 100 sec correlated with ScvO2 (15 mm: R2 = 0.63, 25mm: R2 = 0.67, p < 0.01) without discrepancy (Bland Altman).ConclusionCentral venous oxygen saturation can be estimated from StO2 during a venous occlusion test.

Changes of retinal oxygen saturation during treatment of diabetic macular edema with a pre-defined regimen of aflibercept: a prospective study

PurposeTo study the effect of anti-VEGF therapy for diabetic macular edema (DME) on retinal oxygen saturation (O2S) and its correlation with functional and anatomical changes of retinal tissue.MethodsAn interventional prospective single group study. Included were 10 eyes of 10 patients with visually significant DME which received a fixed regimen of intravitreal aflibercept every 4 weeks for 5 months, followed by 3 injections every 8 weeks, and were controlled monthly. Visual acuity (VA), central retinal thickness (CRT), arterial (aO2S), venous (vO2S) and arterio-venous difference (AVdO2S) retinal oxygen saturation were noted monthly. Changes after 5th (V6) injection and on last follow-up (V12) were studied. Correlations of different parameters were analyzed.ResultsThe aO2S did not change whereas vO2S decreased (62.2 ± 9.4 pre-op to 57.2 ± 10.5 on V6, p = 0.03). This remained unchanged at 59.4 ± 13.2 on V12 (p = 0.2) and was accompanied by an increase of AVdO2S (40.8 ± 8.3 pre-op to 44.8 ± 10.6, p = 0.03 on V6) which was followed by a non-significant decrease to 41.8 ± 11.3 on V12 (p = 0.06). We found no correlation between BCVA and aO2S. However, mild correlation between BCVA and both vO2S and AVdO2S (r = −0.2 p = 0.035 and r = 0.185 p = 0.05 respectively) was found. No correlation was found between CRT and aO2S, vO2S, or AVdO2S.ConclusionsDuring DME treatment with fixed regimen of intravitreal aflibercept over 11 months, we observed a reduction of vO2S and increase of AVdO2S which correlated with BCVA but not CRT. This could be explained by increasing consumption of O2S in the central retina and, possibly, by re-perfusion process.

A comparison of high thoracic epidural anaesthesia versus conventional intravenous opioids in pediatric patients undergoing corrective open heart surgery for ventricular septal defect

Background: We compared high thoracic epidural anaesthesia with a combination of morphine and bupivacaine versus IV fentanyl as an alternative for perioperative pain management.Methods: Group-E: Injection Morphine 75-100 mcg/kg and Injection 0.25 % Bupivacaine 0.5 ml/kg was given via epidural catheter at insertion, Injection 0.25% Bupivacaine 0.5 ml/kg just before skin incision, and continuous infusion of Injection 0.125% Bupivacaine at 0.2 ml/kg/hr intra-operatively. Post-operative 0.1 ml/kg/hr infusion. Group F- intravenous fentanyl 2-3 mcg/Kg IV bolus given just before skin incision, followed by 1-2 mcg/Kg/hr IV fentanyl started after weaning from cardiopulmonary bypass.Results: The mean ScvO2 was comparable between the two groups during induction period but became higher in group E during bypass and post bypass period intraoperatively, and the difference in rise in ScvO2 is statistically significant with a p&lt;0.05. The mean rSo2- C was comparable between the two groups in the first postoperative hour but group F shows higher rSo2-C postoperatively which was statistically significant. The postoperative pain was significantly lower in group E in the postoperative period (except for 4,5,6 and 40 and 48th hour).Conclusions: HTEA to paediatric patients prior to sternotomy for cardiac surgeries resulted in a much better control of haemodynamic parameters. Produces better central venous and regional tissue oxygenation during bypass and post bypass intraoperatively as compared to the patients that received only intravenous fentanyl. There was lower amount of postoperative bleeding in the HTEA group with significant reduction in requirement of post-operative ventilation and time to extubation after surgery, better post-operative pain control and overall outcome.

MO821OXYGEN EXTRACTION RATIO AND MORTALITY RISK IN HAEMODIALYSIS PATIENT: A MULTICENTRE STUDY

Abstract Background and Aims Patients on haemodialysis (HD) suffer a very high rate of cardiovascular mortality with some evidence suggesting a possible association with decreasing blood oxygen saturation (SO2) during sessions. The ratio between arterial SO2 (SaO2) and central venous SO2 (ScvO2) or Oxygen Extraction Ratio (OER), which represents an estimate of the amount of oxygen claimed by peripheral tissues and of the haemodialysis related hypoxic stress, might represent a new prognostic factor. Method We evaluate the relationship between OER values and mortality risks in HD patients in a prospective multicentre observational study. We enrolled chronic HD patients with permanent central venous catheter (CVC) and no fistula, in whom ScvO2 measurement is at hand and SaO2 is available with a peripheral oxymeter. OER ([(SaO2−ScvO2)/SaO2]×100) was measured before and after HD at enrolment (HD OER sessions) in each patients, and a one-year follow-up was planned to record the number of deaths. Results In 101 patients (age 71.5 ± 14 years on dialysis for 47 ± 38 months), during 9 ± 6 months of follow up, we recorded 35 deaths. Patients were then divided into two groups, above or below the median value of pre-HD OER, which was 30%. In these groups, the average incidence of deaths was 12% (24 deaths) and 5,5% (11 deaths) respectively (p&amp;lt;0.05), with significantly different survival curves (Kaplan-Meier log rank test = 0.04, fig). No difference in mortality was evident if we divided patients according to the median intradialytic change in OER value. Conclusion Patients with pre-HD OER &amp;gt; 30% have a higher mortality risk, most probably secondary to reduced capability to respond to HD related oxygen requirements. OER is novel biomarker to identify patients at greatest clinical risk.

Oxygen extraction ratio to identify patients at increased risk of intradialytic hypotension

Intradialytic hypotension (IDH) is a hemodynamic phenomenon recently associated with decreased blood oxygen saturation (SO2). The ratio between peripheral oxygen saturation (SpO2) and central venous SO2 (ScvO2) or Oxygen Extraction Ratio (OER), which represents a roughly estimate of the amount of oxygen claimed by peripheral tissues, might be used to estimate haemodialysis (HD) related hypoxic stress. Aim of this pilot study was to evaluate the relationship between OER increments during dialysis sessions (ΔOER) and episodes of IDH. We enrolled chronic HD patients with permanent central venous catheter (CVC) and no fistula, in whom ScvO2 measurement is at hand. OER ([(SpO2 − ScvO2)/SpO2] × 100) was measured in three consecutive HD sessions (HD OER sessions) before HD, after 15′, 30′ and 60′ min and at the end of HD. Then, a one-year follow-up was planned to record the number of IDH episodes. In the 28 enrolled patients (age 74 ± 2.6 years), during 12 ± 1.2 months of follow up, incidence of IDH was 3.6%. We divided patients into two groups, above or below the median value of ΔOER at the end of HD, which was 36%. In these groups, the average incidence of IDH was 7% and 2% respectively (p < 0.01), while OER values before HD were not different. Notably, in the high ΔOER group the OER increment was evident since after 15′ and was significantly higher than in the low ∆OER group (∆OER-15′ = 19 ± 3.0% vs. 9.0 ± 3.0%; p < 0.05). By comparison, blood volume changes overlapped in the two groups (average change − 9 ± 0.8%). Values of ∆OER > 19% after only 15′ of HD treatment or > 36% at the end of the session characterize patients with higher rates of hypotension. Intradialytic ∆OER, a parameter of tissue hypoxic stress, identifies more fragile patients at greater risk of IDH.

Efficacy of beta-blockers in the treatment of sepsis

This meta-analysis is to systematically evaluate the efficacy and safety of beta-blockers in the treatment of sepsis. A total of 17 articles that met the inclusion criteria were included, and 10,385 cases were obtained. The meta-analysis results showed that patients with sepsis with beta-blocker usage had a significantly lower 28-day mortality. The heart rate decreased over time in patients with sepsis using beta-blocker. Moreover, central venous blood oxygen saturation increased after 24, 48, 72 hours of treatment; lactic acid and cardiac troponin I decreased after 48, 72 hours of treatment; and tumor necrosis factor-α, interleukin-1β levels decreased significantly after 12, 24, 48, 72 hours of treatment (p&lt;0.05). In conclusion, beta-blockers reduce 28-day mortality and heart rate.

Individualized use of levosimendan in cardiac surgery

Levosimendan is acardiac inotrope that augments myocardial contractility without increasing myocyte oxygen consumption. Additionally, levosimendan has been shown to exhibit anti-inflammatory, antioxidative, and other cardioprotective properties and is approved for treatment of heart failure. Recent studies indicated that these beneficial effects can be achieved with doses lower than the standard dose of 12.5 mg. Patients with preoperatively diagnosed left ventricular ejection fraction (LVEF) ≤40% received 1.25 mg levosimendan after induction of anesthesia. After surgery, administration of low-dose levosimendan was repeated until cardiovascular stability was achieved. This study aimed to evaluate if pharmacological preconditioning with 1.25 mg levosimendan in patients with LVEF ≤40% altered the postoperative need for inotropic agents, the incidence of newly occurring atrial fibrillation, renal replacement therapy, mechanical circulatory support and 30-day mortality. The cumulative dosage of levosimendan was recorded to assess the required dosage in the context of individualized treatment. This retrospective study included patients with preoperatively diagnosed LVEF ≤40% who underwent cardiac surgery at this institution between January 2015 and December 2018 and who received 1.25 mg levosimendan after induction of anesthesia to prevent postoperative low cardiac output syndrome. Based on echocardiography results, invasive hemodynamic monitoring, and central venous or mixed venous oxygen saturation and lactate clearance, repetitive doses of levosimendan in 1.25 mg increments could be postoperatively administered until cardiovascular stability was achieved. The results were compared to the current literature. We identified 183patients with LVEF <40% who received pharmacological preconditioning with 1.25 mg levosimendan. Maximum doses of epinephrine, incidence of atrial fibrillation, need for renal replacement therapy and 30-day mortality were found to be below the published rates of comparable patient collectives. In 73.2% of patients, acumulative dosage of 5 mg levosimendan or less was considered sufficient. The presented concept of pharmacological preconditioning with 1.25 mg levosimendan followed by individualized additional dosing in cardiac surgery patients with preoperative LVEF ≤40% suggests that this concept is safe, with possible advantages regarding the need of inotropic agents, renal replacement therapy, and 30-day mortality, compared to the current literature. Individualized treatment with levosimendan to support hemodynamics and atimely reduction of inotropic agents needs further confirmation in randomized trials.

P1305CARDIAC OUTPUT AND ESTIMATED UPPER BODY BLOOD FLOW

Abstract Background and Aims Cardiopulmonary monitoring during hemodialysis has the potential to improve dialysis adequacy, prevent adverse events, improve quality of dialysis patients’ lives and reduce mortality risks. Under stable conditions the knowledge of upper body oxygen consumption, the difference between arterial and venous oxygen saturation (ScvO2) and hemoglobin concentrations allow the calculation of estimated UBBF (eUBBF; Rosales 2019). We studied the association between eUBBF and cardiac output during hemodialysis. Method In patients with a central venous catheter as the vascular access, we simultaneously measured intradialytic central-venous oxygen saturation and hemoglobin levels once per minute using the Crit-Line Monitor (Fresenius Medical Care North America, Waltham, USA). Concomitantly we measured cardiac output (CO) using the Task Force Monitor (CNSystems, Graz, Austria). We depicted CO and eUBBF as box-whiskers in 5 minute periods from 20 to 180 minutes, tested the minute-level time series for stationarity using the Dickey-Fuller test, employed differencing to make the time series stationary, and tested for linear associations using cross-correlations and determined if the CO time series was useful to predict the eUBBF time series using the Granger Causality test. Results We studied 13 patients (59±14 years, 5 (38%) male, 93±22 kg pre-dialysis weight 170±7 cm tall) during 34 hemodialyses. CO and UBBF was 4.7±1.0 and 1.3±0.4 L/min, and showed a small trend downward for CO during hemodialysis. Cross-correlations showed no remarkable correlations for all treatments, Granger causality index was less than 20% in 8 treatments however without clearly discernible patterns. Conclusion Despite variability in the CO the eUBBF remains stable, a dynamic which pathophysiologically appears plausible. While testing for linear associations yielded no significant relationships, based on the Granger causality test there nevertheless appears to be some form of a relationship which requires some further investigation which will need to also include aspects such as fluid overload, body temperature and total peripheral resistance. Based on this data, cardiopulmonary monitoring appears possible and yields a reliable continuous overview of the hemodynamic status of a patient.

Postoperative cognitive dysfunction after robot-assisted radical cystectomy (RARC) with cerebral oxygen monitoring an observational prospective cohort pilot study

BackgroundThe incidence and risk factors of postoperative cognitive dysfunction (POCD) during robot-assisted radical cystectomy (RARC) in extreme Trendelenburg positioning and pneumoperitoneum are still controversial. The aim of this prospective observational study was to find the incidence rate as well as possible risk factors of POCD in RARC with cerebral oxygen monitoring.MethodsPatients who underwent RARC and open abdominal surgery in horizontal positioning were included. Preoperative and postoperative arterial blood gas (ABG), S-100β, C-reactive protein (CRP), and cognitive dysfunction scales were tested. Also, we used Z score to analyze and comprehensively evaluate POCD. Measurements of heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), end-tidal CO2 (etCO2), and cerebral oxygen were immediately obtained after different time points during the surgery.ResultsHere, 24 and 23 patients were included in the RARC group and in the control group, respectively. The incidence of POCD didn’t have significant difference in RARC group (45.8%), in contrast to the control group (26.1%). The laboratory tests of s100β and CRP between two groups didn’t contain significant difference as well. As duration of Trendelenburg and pneumoperitoneum prolonged, the cerebral oxygen saturation in the RARC group increased, which didn’t cause excessive perfusion nevertheless (rSO2<75%). We compared laboratory tests, age, education status, blood loss, and fluid input between POCD and non-POCD patients. A significant difference was found in the serum concentrations of CRP (72.59 ± 42.09 vs. 48.50 ± 26.53, P = 0.025) and age (69.20 ± 7.033 vs. 65.34 ± 5.228, P = 0.041).ConclusionRARC in extreme Trendelenburg positioning and pneumoperitoneum did not significantly increase the incidence of POCD and didn’t cause excessive perfusion. The inflammation marker CRP and age might be independent risk factors of POCD.Trial registrationClinicaltrials.gov with registration number NCT03372135. Registered 1 November 2017 (retrospectively registered).

Central venous oxygen saturation/lactate ratio: a novel predictor of outcome following emergency open laparotomy.

Emergency laparotomy is associated with high rates of morbidity and mortality. The need for highly sensitive readily prognostic biomarkers is necessary to improve the outcome. We investigated the usefulness of post-operative arterial lactate and ScvO2/lactate ratio as predictors of outcome after post-operative emergency open laparotomy. To the best of our knowledge, the novel ScvO2/lactate ratio was not investigated before in emergency open laparotomy patients. It is a prospective observational cohort study. We investigated the usefulness of post-operative arterial lactate and ScvO2/lactate ratio as predictors of early mortality in 40 patients following emergency open laparotomy admitted to the ICU. Admission and 24h lactate levels were predictor of mortality with cut-off point > 3.95mmol/L, sensitivity 100%, and specificity 93.3%, and cut-off > 3.5mmol/L, sensitivity 100%, and specificity 96.7%, respectively. In this study, ScvO2/lactate ratio on admission was predictor of at day 7 with cut-off point < 13.95, sensitivity 100%, and specificity 96.7% p < 0.0001. Lactate at 12 and 24h was also predictor of survival p < 0.0001. Serial arterial lactate was highly correlated to ICU length of stay; admission APACHE II and day 1; and 2 MODS and SOFA scores (p < 0.001). Serial blood lactate as well as the novel ScvO2/lactate ratio can be useful for early predictors of mortality at 7days. Serial lactate levels correlate to admission ICU scores APACHE II; MODS and SOFA in post-operative emergency open laparotomy patients.

Correlation Between External Jugular Venous and Central Venous Blood Oxygen Saturation in Patient Under General Anesthesia

Correlation Between External Jugular Venous and Central Venous Blood Oxygen Saturation in Patient Under General Anesthesia

Predictive value of airway closure pressure and change rate of the saturation of the central venous oxygen in weaning patients underwent mechanical ventilation

目的 探讨口腔闭合压(P0.1)和中心静脉血氧饱和度变化率(△SCVO2)对机械通气患者撤机的预测价值。 方法 选取2016年4月至2018年4月苍南县第二人民医院重症监护病房(ICU)收治的机械通气患者50例作为研究对象，对患者实施P0.1和△SCVO2等的检测，并根据患者撤机是否成功分为拔管不成功(EF)组和拔管成功(ES)组，比较两者的撤机参数。 结果 50例接受机械通气的患者中，ES组36例，EF组14例，两组患者改良吸吸机撤机指数[(23.75±2.31)分比(22.10±2.74)分，t＝2.152，P＝0.051]、自主呼吸试验(SBT)前[(72.17±10.23)%比(73.20±6.54)%，t＝0.349，P＝0.733]及SBT 30 min[(74.23±9.67)%比(68.09±7.23)%，t＝2.148，P＝0.051]SCVO2差异无统计学意义，ES组的P0.1[(4.21±0.87)%比(6.71±1.21)%，t＝8.150，P＝0.000]和△SCVO2[(2.85±0.13)%比(6.98±0.12)%，t＝102.948，P＝0.000]明显低于EF组。P0.1与拔管成功呈负相关关系(r＝－0.517，P＝0.037)，△SCVO2与拔管成功呈正相关(r＝0.621，P＝0.021)关系。P0.1＝4.60 cmH2O为预测机械通气患者能否成功撤机临界参考阈值，灵敏度为92.7%，特异度为76.0%。△SCVO2＝4.80%为临界参考阈值，敏感度为94.3%，特异度为91.4%。 结论 机械通气患者的撤机中，P0.1为4.60 cmH2O和△SCVO2为4.80%是EF的可靠预测指标。

Assessment of Regional Perfusion and Organ Function: Less and Non-invasive Techniques.

Sufficient organ perfusion essentially depends on preserved macro- and micro-circulation. The last two decades brought substantial progress in the development of less and non-invasive monitoring of macro-hemodynamics. However, several recent studies suggest a frequent incoherence of macro- and micro-circulation. Therefore, this review reports on interactions of macro- and micro-circulation as well as on specific regional and micro-circulation. Regarding global micro-circulation the last two decades brought advances in a more systematic approach of clinical examination including capillary refill time, a graded assessment of mottling of the skin and accurate measurement of body surface temperatures. As a kind of link between macro- and microcirculation, a number of biochemical markers can easily be obtained. Among those are central-venous oxygen saturation (ScvO2), plasma lactate and the difference between central-venous and arterial CO2 (cv-a-pCO2-gap). These inexpensive markers have become part of clinical routine and guideline recommendations. While their potential to replace parameters of macro-circulation such as cardiac output (CO) is limited, they facilitate the interpretation of the adequacy of CO and other macro-circulatory markers. Furthermore, they give additional hints on micro-circulatory impairment. In addition, a number of more sophisticated technical approaches to quantify and visualize micro-circulation including video-microscopy, laser flowmetry, near-infrared spectroscopy (NIRS), and partial oxygen pressure measurement have been introduced within the last 20 years. These technologies have been extensively used for scientific purposes. Moreover, they have been successfully used for educational purposes and to visualize micro-circulatory disturbances during sepsis and other causes of shock. Despite several studies demonstrating the association of these techniques and parameters with outcome, their practical application still is limited. However, future improvements in automated and “online” diagnosis will help to make these technologies more applicable in clinical routine. This approach is promising with regard to several studies which demonstrated the potential to guide therapy in different types of shock. Finally several organs have specific patterns of circulation related to their special anatomy (liver) or their auto-regulatory capacities (brain, kidney). Therefore, this review also discusses specific issues of monitoring liver, brain, and kidney circulation and function.

Tracking Arteriovenous Fistula Maturation: A Novel Approach

Background: The time between the creation of an arteriovenous fistula (AVF) and its successful use is significantly longer in hemodialysis (HD) patients in the United States compared to those in other countries, and there is an urgent need to reduce the residence time of central-venous catheters (CVC). Methods: Successful AVF creation and maturation results in typical hemodynamic changes, such as an increase in cardiac output and upper body blood flow (UBBF). In patients with CVC as vascular access, we measured once per minute intradialytic central-venous oxygen saturation (ScvO₂) and hemoglobin levels simultaneously using the Crit-Line Monitor. Under conditions of stable upper body oxygen consumption and arterial oxygen saturation, ScvO₂ and hemoglobin concentration allows the calculation of estimated UBBF (eUBBF). In a quality improvement project, we used ScvO₂ and eUBBF to track the hemodynamic changes accompanying AVF maturation. Results: Out of 11 patients (9 incident to HD, 1 female, age 61 ± 13 years), AVF maturation was successful in 9. In 1 patient, the AVF did not mature. One patient died from sudden cardiac death with a maturing AVF. In the 9 patients with successful AVF maturation, ScvO₂ increased from 60.9 ± 2.7% prior to AVF creation to 73.4 ± 3.6% a week after AVF creation (19.6 ± 6.3% increase). eUBBF increased from 1.3 ± 0.3 to 2.2 ± 0.6 L/min (62.7 ± 37.5% increase); no material ScvO₂ or eUBBF changes occurred in the other 2 patients. Conclusion: Our results indicate the potential utility of ScvO₂ and eUBBF to track the hemodynamic response to AVF maturation. To what extent these insights translate into shortening of the time between AVF creation and successful cannulation warrants further investigations.