Practical Use of Lactate Levels in the Intensive Care

Association between Serum Lactate and Morbidity and Mortality in Neonates: A Systematic Review and Meta-Analysis

OBJECTIVE

Lactate is a marker of hypoperfusion in critically ill patients. Whether lactate is useful for identifying and stratifying neonates with a higher risk of adverse outcomes remains unknown. This study aimed to investigate the association between lactate and morbidity and mortality in neonates.

METHODS

A meta-analysis was performed to determine the association between blood lactate levels and outcomes in neonates. Ovid MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov were searched from inception to 1 May 2021. A total of 49 observational studies and 14 data accuracy test studies were included. The risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies and the QUADAS-2 tool for data accuracy test studies. The primary outcome was mortality, while the secondary outcomes included acute kidney injury, necessity for renal replacement therapy, neurological outcomes, respiratory morbidities, hemodynamic instability, and retinopathy of prematurity.

RESULTS

Of the 3184 articles screened, 63 studies fulfilled all eligibility criteria, comprising 46,069 neonates. Higher lactate levels are associated with mortality (standard mean difference, -1.09 [95% CI, -1.46 to -0.73]). Using the estimated sensitivity (0.769) and specificity (0.791) and assuming a prevalence of 15% for adverse outcomes (median of prevalence among studies) in a hypothetical cohort of 10,000 neonates, assessing the lactate level alone would miss 346 (3.46%) cases (false negative) and wrongly diagnose 1776 (17.76%) cases (false positive).

CONCLUSIONS

Higher lactate levels are associated with a greater risk of mortality and morbidities in neonates. However, our results do not support the use of lactate as a screening test to identify adverse outcomes in newborns. Research efforts should focus on analyzing serial lactate measurements, rather than a single measurement.

Implementing Pediatric Surviving Sepsis Campaign Guidelines: Improving Compliance With Lactate Measurement in the PICU

The 2020 pediatric Surviving Sepsis Campaign (pSSC) recommends measuring lactate during the first hour of resuscitation for severe sepsis/shock. We aimed to improve compliance with this recommendation for patients who develop severe sepsis/shock while admitted to the PICU.

DESIGN

Structured, quality improvement initiative.

SETTING

Single-center, 26-bed, quaternary-care PICU.

PATIENTS

All patients with PICU-onset severe sepsis/shock from December 2018 to December 2021.

INTERVENTIONS

Creation of a multidisciplinary local sepsis improvement team, education program targeting frontline providers (nurse practitioners, resident physicians), and peer-to-peer nursing education program with feedback to key stakeholders.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure was compliance with obtaining a lactate measurement within 60 minutes of the onset of severe sepsis/shock originating in our PICU using a local Improving Pediatric Sepsis Outcomes database and definitions. The process measure was time to first lactate measurement. Secondary outcomes included number of IV antibiotic days, number of vasoactive days, number of ICU days, and number of ventilator days. A total of 166 unique PICU-onset severe sepsis/shock events and 156 unique patients were included. One year after implementation of our first interventions with subsequent Plan-Do-Study-Act cycles, overall compliance increased from 38% to 47% (24% improvement) and time to first lactate decreased from 175 to 94 minutes (46% improvement). Using a statistical process control I chart, the preshift mean for time to first lactate measurement was noted to be 179 minutes and the postshift mean was noted to be 81 minutes demonstrating a 55% improvement.

CONCLUSIONS

This multidisciplinary approach led to improvement in time to first lactate measurement, an important step toward attaining our target of lactate measurement within 60 minutes of septic shock identification. Improving compliance is necessary for understanding implications of the 2020 pSSC guidelines on sepsis morbidity and mortality.

Risk stratification of patients with acute respiratory distress syndrome complicated with sepsis using lactate trajectories

Background

No consensus has been reached on an optimal blood lactate evaluation system although several approaches have been reported in the literature in recent years. A group-based trajectory modeling (GBTM) method could better stratify patients with acute respiratory distress syndrome (ARDS) complicated with sepsis in the intensive care unit (ICU).

Patients and methods

760 patients from the comprehensive ICU of Tianjin Medical University General Hospital with ARDS complicated with sepsis were eligible for analysis. Serial serum lactate levels were measured within 48 h of admission. In addition to the GBTM lactate groups, the initial lactate, peak lactate level, the area under the curve of serial lactate (lactate AUC), and lactate clearance were also considered for comparison. The short- and long-term outcomes were the 30- and 90-day mortality, respectively.

Results

Three lactate groups were identified based on GBTM, with group 3 exhibiting the worse short- [hazard ratio (HR) for 30-day mortality: 2.96, 95% confidence interval (CI) 1.79–4.87, P < 0.001] and long term (HR for 90-day mortality: 3.49, 95% CI 2.06–5.89, P < 0.001) outcomes followed by group 2 (HR for 30-day mortality: 2.05, 95% CI 1.48–2.84, P < 0.001 and HR for 90-day mortality: 1.99, 95% CI 1.48–2.67, P < 0.001). GBTM lactate groups exhibited significantly improved diagnostic performance of initial lactate + SOFA scores/APACHE II scores models. Based on the multivariable fractional polynomial interaction (MFPI) approach, GBTM lactate groups could better differentiate high-risk patients than the initial lactate groups in short- and long-term outcomes.

Conclusions

To the best of our knowledge, this is the first report that GBTM-based serial blood lactate evaluations significantly improve the diagnostic capacity of traditional critical care evaluation systems and bring many advantages over previously documented lactate evaluation systems.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02132-6.

Diagnostic Modalities in Critical Care: Point-of-Care Approach

The concept of intensive care units (ICU) has existed for almost 70 years, with outstanding development progress in the last decades. Multidisciplinary care of critically ill patients has become an integral part of every modern health care system, ensuing improved care and reduced mortality. Early recognition of severe medical and surgical illnesses, advanced prehospital care and organized immediate care in trauma centres led to a rise of ICU patients. Due to the underlying disease and its need for complex mechanical support for monitoring and treatment, it is often necessary to facilitate bed-side diagnostics. Immediate diagnostics are essential for a successful treatment of life threatening conditions, early recognition of complications and good quality of care. Management of ICU patients is incomprehensible without continuous and sophisticated monitoring, bedside ultrasonography, diverse radiologic diagnostics, blood gas analysis, coagulation and blood management, laboratory and other point-of-care (POC) diagnostic modalities. Moreover, in the time of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, particular attention is given to the POC diagnostic techniques due to additional concerns related to the risk of infection transmission, patient and healthcare workers safety and potential adverse events due to patient relocation. This review summarizes the most actual information on possible diagnostic modalities in critical care, with a special focus on the importance of point-of-care approach in the laboratory monitoring and imaging procedures.

Modeling Challenge Data to Quantify Endogenous Lactate Production

With the intention of isolating the susceptibility of modeling methodology to influence our investigation of the infusion data, we used three kinetic approaches to our models: a simple approach, a unit approach, and a novel approach. The simple approach used exclusively built-in modeling features of the software in terms of units of the infusion dilution (mmol/L), as well as in terms of the precision of switching the infusion on and off. The unit approach used the same switching mechanism as the simple approach, but the units were modeled in those of the infusion (e.g., mmol/kg). Thirdly with the novel approach, we used an automated approach to controlling the infusion, in the sense that as the modeling mechanism sensed the slowdown of the infusion, it was gradually turned off. The units of the analysis for the novel approach were exactly the same as those deployed in the unit approach. Our objective here was to see if common pharmacokinetic parameters were seriously impacted by the particular modeling method.

Pre-Hospital Lactatemia Predicts 30-Day Mortality in Patients with Septic Shock-Preliminary Results from the LAPHSUS Study

Background: Assessment of disease severity in patients with septic shock (SS) is crucial in determining optimal level of care. In both pre- and in-hospital settings, the clinical picture alone is not sufficient for assessing disease severity and outcomes. Because blood lactate level is included in the clinical criteria of SS it should be considered to improve the assessment of its severity. This study aims to investigate the relationship between pre-hospital blood lactate level and 30-day mortality in patients with SS. Methods: From 15 April 2017 to 15 April 2019, patients with SS requiring pre-hospital Mobile Intensive Care Unit intervention (MICU) were prospectively included in the LAPHSUS study, an observational, non-randomized controlled study. Pre-hospital blood lactate levels were measured at the time of first contact between the patients and the MICU. Results: Among the 183 patients with septic shock requiring action by the MICU drawn at random from LAPHSUS study patients, six (3%) were lost to follow-up on the 30th day and thus 177 (97%) were analyzed for blood lactate levels (mean age 70 ± 14 years). Pulmonary, urinary and digestive infections were probably the cause of the SS in respectively 58%, 21% and 11% of the cases. The 30-day overall mortality was 32%. Mean pre-hospital lactatemia was significantly different between patients who died and those who survived (respectively 7.1 ± 4.0 mmol/L vs. 5.9 ± 3.5 mmol/L, p < 10⁻³). Using Cox regression analysis adjusted for potential confounders we showed that a pre-hospital blood lactate level ≥ 4 mmol/L significantly predicted 30-day mortality in patients with SS (adjusted hazard ratio = 2.37, 95%CI (1.01–5.57), p = 0.04). Conclusion: In this study, we showed that pre-hospital lactatemia predicts 30-day mortality in patients with septic shock handled by the MICU. Further studies will be needed to evaluate if pre-hospital lactatemia alone or combined with clinical scores could affect the triage decision-making process for those patients.

Hypoxemia Index Associated with Prehospital Intubation in COVID-19 Patients

BACKGROUND

There exists a need for prognostic tools for the early identification of COVID-19 patients requiring prehospital intubation. Here we investigated the association between a prehospital Hypoxemia Index (HI) and the need for intubation among COVID-19 patients in the prehospital setting.

METHODS

We retrospectively analyzed COVID-19 patients initially cared for by a Paris Fire Brigade advanced life support (ALS) team in the prehospital setting between 8th March and 18th April of 2020. We assessed the association between HI and prehospital intubation using receiver operating characteristic (ROC) curve analysis and logistic regression model analysis after propensity score matching. Results are expressed as odds ratio (OR) and 95% confidence interval (CI).

RESULTS

We analyzed 300 consecutive COVID-19 patients (166 males (55%); mean age, 64 ± 18 years). Among these patients, 45 (15%) were deceased on the scene, 34 (11%) had an active care restriction, and 18 (6%) were intubated in the prehospital setting. The mean HI value was 3.4 ± 1.9. HI was significantly associated with prehospital intubation (OR, 0.24; 95% CI: 0.12-0.41, p < 10^-3) with a corresponding area under curve (AUC) of 0.91 (95% CI: 0.85-0.98). HI significantly differed between patients with and without prehospital intubation (1.0 ± 1.0 vs. 3.6 ± 1.8, respectively; p < 10^-3). ROC curve analysis defined the optimal HI threshold as 1.3. Bivariate analysis revealed that HI <1.3 was significantly, positively associated with prehospital intubation (OR, 38.38; 95% CI: 11.57-146.54; p < 10^-3). Multivariate logistic regression analysis demonstrated that prehospital intubation was significantly associated with HI (adjusted odds ratio (ORa), 0.20; 95% CI: 0.06-0.45; p < 10^-3) and HI <3 (ORa, 51.08; 95% CI: 7.83-645.06; p < 10^-3). After adjustment for confounders, the ORa between HI <1.3 and prehospital intubation was 3.6 (95% CI: 1.95-5.08; p < 10^-3).

CONCLUSION

An HI of <1.3 was associated with a 3-fold increase in prehospital intubation among COVID-19 patients. HI may be a useful tool to facilitate decision-making regarding prehospital intubation of COVID-19 patients initially cared for by a Paris Fire Brigade ALS team. Further prospective studies are needed to confirm these preliminary results.

The Added Value of Lactate and Lactate Clearance in Prediction of In-Hospital Mortality in Critically Ill Patients With Sepsis

Supplemental Digital Content is available in the text.

We investigated the added predictive value of lactate and lactate clearance to the Acute Physiology and Chronic Health Evaluation IV model for predicting in-hospital mortality in critically ill patients with sepsis.

Real-world clinical experience with the percutaneous extracorporeal life support system: Results from the German Lifebridge® Registry

BACKGROUND

The concept of percutaneous extracorporeal life support (ECLS) is based on immediate cardiovascular stabilization allowing for sufficient end-organ perfusion, thus improving the outcome in patients with circulatory arrest. Lifebridge^® (Zoll Medical GmbH, Germany) is a portable ECLS device designed for rapid application due to its automated set-up.

METHODS

A total of 60 tertiary cardiovascular centers were interrogated with regard to application and short-term results after use of Lifebridge ECLS system. Detailed data were collected by standardized case report forms in all centers consented to participate in the study. Demographic and clinical baseline characteristics of the patient population, procedural and follow-up data were recorded and analyzed.

RESULTS

In total, 444 patients were analyzed regarding mortality. The detailed study cohort consisted of 112 patients. A total of 80% of the study subjects represented patients post cardiopulmonary resuscitation, 43% were in cardiogenic shock and 50% suffered from acute myocardial infarction. The survival rates were 36% immediately after device implementation and 16% after 30 days. Multivariable analysis revealed that only serum lactate concentration at admission could be proven as independent predictor of patients' outcome. Patients with lactate concentrations above 10 mmol/L exhibited > 95% mortality (p < 0.05 versus below 10 mmol/L).

CONCLUSION

The present study provides real-world clinical data of patients treated with a transportable automated ECLS system. In conclusion, Lifebridge is a safely applicable cardiorespiratory stabilization tool associated with acceptable complication rates. Nevertheless, mortality rates were high in these critically ill patients, especially in those showing high lactate concentrations at admission.