Blood lactate monitoring in critically ill patients: A systematic health technology assessment *:

Malign asitli over kanserinde sitoredüktif cerrahide perioperatif hemodinamik optimizasyon

Purpose: In this study, we aimed to evaluate the effects of norepinephrine and albumin use in patients with epithelial ovarian cancer with malignant ascite in order to maintain plasma oncotic pressure and intravascular volume, to provide perioperative hemodynamic stabilization and tissue perfusion. In addition, it was aimed to compare in terms of postoperative intensive care admission, hospital stay and complications. Materials and Methods: A total of 66 patients, 38 with ascites and 28 without ascites, who underwent cytoreductive surgery for ovarian cancer were included in this study. PVI and invasive arterial monitoring of the patients were performed after hemodynamic stabilization (after the start of surgery) (T0). T0, 1st hour (T1) and 2nd hour (T2) and postoperative (Tpostop.) Ascites patients were composed of 3 subgroups which the ones received norepinephrine (NE) infusion, norepinephrine + albumin (NEA) infusion or only fluid therapy (FT). From the perioperative hemodynamic and laboratory data of the patients, tissue perfusion was evaluated with lactate, and hemodynamic status was evaluated with pleth variability index (PVI), perfusion index (PI) and mean arterial pressure (MAP). Results: Demographic and clinical findings did not differ significantly between patients with and without ascites. Lactate level in NEA / NE group in Tpostop, PVI level in T1h, T2h and Tpostop time frames were determined higher than the FT group. PI was found to be significantly lower in the T2 time frame. The postoperative ICU admission rate was higher in the NEA and NE groups. The duration of ICU stay in group NEA was shorter than in group NE. Conclusion: We recommend the use of low-dose NE with albumin to provide perioperative hemodynamic optimization, tissue perfusion and plasma oncotic pressure in surgery of ovarian cancer with malignant ascites. Despite high fluid replacement in these patients, the use of norepinephrine and albumin together may have an important role in preventing / reducing major complications in the perioperative period.

Study of Utility of Basic Arterial Blood Gas Parameters and Lactate as Prognostic Markers in Patients With Severe Dengue

Background

The importance of prognostication in critical care cannot be over-emphasized, especially in the context of diseases like dengue, as their presentation may vary from mild fever to critical life-threatening illness. With the help of prognostic markers, it is possible to identify patients at higher risk and thus improve their outcome with timely intervention. Basic arterial blood gas (ABG) parameters, i.e., potential of hydrogen (pH), partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2) and bicarbonate are useful parameters, especially in critical care medicine as they are known to vary with the severity of illness. Hyperlactatemia is often referred to as a “powerful predictor of mortality”. Basic ABG parameters and lactate have been used as an essential prognostic modality in critically ill patients for decades; however, the evidence remains limited for their role as prognostic markers in patients with severe dengue.

Method

We carried out an observational retrospective cohort study comprising 163 patients with severe dengue, admitted between July 2021 and November 2021 at Medical Intensive Care Unit (MICU) of Shri Ram Murti Smarak Institute of Medical Sciences (SRMS IMS), Bareilly, Uttar Pradesh, India. Basic ABG parameters and lactate levels at the time of admission to MICU were compared between survivor and non-survivor groups of patients with severe dengue in order to evaluate their prognostic utility as predictors of mortality.

Results

pH (p<0.0001), PO2 (p=0.01) and bicarbonate (<0.0001) levels were significantly lower, while PCO2 (p=0.002) and lactate (p<0.0001) levels were significantly higher in non-survivor group as compared to survivor group. Lactate was found to be the best prognostic marker with Area Under the Curve (AUC) of 88.7% on Receiver Operating Characteristics (ROC) analysis.

Conclusion

Basic arterial blood gas parameters and lactate can be used as feasible prognostic markers in patients with severe dengue.

Prediction of 6-Month Mortality Using Pre-Extracorporeal Membrane Oxygenation Lactate in Patients with Acute Coronary Syndrome Undergoing Veno-Arterial-Extracorporeal Membrane Oxygenation

Background

The effectiveness of extracorporeal membrane oxygenation (ECMO) for patients with refractory cardiogenic shock or cardiac arrest is being established, and serum lactate is well known as a biomarker of end-organ perfusion. We evaluated the efficacy of pre-ECMO lactate for predicting 6-month survival in patients with acute coronary syndrome (ACS) undergoing ECMO.

Methods

We reviewed the medical records of 148 patients who underwent veno-arterial (VA) ECMO for ACS between January 2015 and June 2020. These patients were divided into survivors and non-survivors based on 6-month survival. All clinical data before and during ECMO were compared between the 2 groups.

Results

Patients’ mean age was 66.0±10.5 years, and 116 (78.4%) were men. The total survival rate was 45.9% (n=68). Cox regression analysis showed that the pre-ECMO lactate level was an independent predictor of 6-month mortality (hazard ratio, 1.210; 95% confidence interval [CI], 1.064–1.376; p=0.004). The area under the receiver operating characteristic curve of pre-ECMO lactate was 0.64 (95% CI, 0.56–0.72; p=0.002; cut-off value=9.8 mmol/L). Kaplan-Meier survival analysis showed that the cumulative survival rate at 6 months was significantly higher among patients with a pre-ECMO lactate level of 9.8 mmol/L or less than among those with a level exceeding 9.8 mmol/L (57.3% vs. 31.8%, p=0.0008).

Conclusion

A pre-ECMO lactate of 9.8 mmol/L or less may predict a favorable outcome at 6 months in ACS patients undergoing VA-ECMO. Further research aiming to improve the accuracy of predictions of reversibility in patients with high pre-ECMO lactate levels is essential.

Composite Hydrogels Containing Bioactive Microreactors for Optical Enzymatic Lactate Sensing

Continuously monitoring specific biomarkers offer a promising method to interrogate disease status and progression. In this work we have demonstrated a composite hydrogel-based sensing platform that may be used for optical detection of lactate. The sensor design consists of microsized enzymatic sensors that are embedded in an outer hydrogel matrix. In these engineered microdomains, encapsulated lactate oxidase serves as the bioactive component, phosphorescent metalloporphyrin acts as the optical transducer, and polyelectrolyte multilayers coated on the enzymatic microsensors control the permeation of lactate into the microsensors. The response of the composite hydrogel-based lactate sensors was characterized by subjecting the sensors to lactate concentration challenges at low physiological oxygen levels. The analytical range and the mean sensitivity were determined to be 9.2 ± 0.83 mg/dL and 11 ± 0.90% dL mg^-1, respectively. Repeated cyclic exposure to high levels of lactate revealed that these sensors were extremely stable, with no significant loss in sensor response after 20 cycles. These preliminary results support the premise that these composite hydrogels are capable of continuous lactate tracking and have the potential for use as fully implantable optical lactate sensors.