Lactate and combined parameters for triaging sepsis patients into intensive care facilities

Pre and postoperative lactate levels and lactate clearance in predicting in-hospital mortality after surgery for gastrointestinal perforation

Background

This study aimed to compare the prognostic significance of pre and postoperative lactate levels and postoperative lactate clearance in the prediction of in-hospital mortality after surgery for gastrointestinal (GI) perforation.

Methods

Among patients who underwent surgery for GI perforation between 2013 and 2017, only patients whose lactate were measured before and after surgery were included and divided into an in-hospital mortality group and a survival group. Data on demographics, comorbidities, pre and postoperative laboratory test results, and operative findings were collected. Risk factors for in-hospital mortality were identified, and receiver-operating characteristic (ROC) curve analysis was performed for pre and postoperative lactate levels and postoperative lactate clearance.

Results

Of 104 included patients, 17 patients (16.3%) died before discharge. The in-hospital mortality group demonstrated higher preoperative lactate (6.3 ± 5.1 vs. 3.5 ± 3.2, P = 0.013), SOFA score (4.5 ± 1.7 vs. 3.4 ± 2.3, P = 0.004), proportions of patients with lymphoma (23.5% vs. 2.3%, P = 0.006), and rates of contaminated ascites (94.1% vs. 68.2%, P = 0.036) and lower preoperative hemoglobin (10.4 ± 1.6 vs. 11.8 ± 2.4, P = 0.018) compare to the survival group. Multivariate analysis revealed that postoperative lactate (HR 1.259, 95% CI 1.084–1.463, P = 0.003) and preoperative hemoglobin (HR 0.707, 95% CI 0.520–0.959, P = 0.026) affected in-hospital mortality. In the ROC curve analysis, the largest area under the curve (AUC) was shown in the postoperative lactate level (AUC = 0.771, 95% CI 0.678–0.848).

Conclusion

Of perioperative lactate levels in patients underwent surgery for GI perforation, postoperative lactate was the strongest predictor for in-hospital mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01479-1.

Consensus on predictors of clinical deterioration in emergency departments: A Delphi process study

AIM

The study aim was to determine relevance and applicability of generic predictors of clinical deterioration in emergency departments based on consensus among clinicians.

METHODS

Thirty-three predictors of clinical deterioration identified from literature were assessed in a modified two-stage Delphi-process. Sixty-eight clinicians (physicians and nurses) participated in the first round and 48 in the second round; all treating hospitalized patients in Danish emergency departments, some with pre-hospital experience. The panel rated the predictors for relevance (relevant marker of clinical deterioration) and applicability (change in clinical presentation over time, generic in nature and possible to detect bedside). They rated their level of agreement on a 9-point Likert scale and were also invited to propose additional generic predictors between the rounds. New predictors suggested by more than one clinician were included in the second round along with non-consensus predictors from the first round. Final decisions of non-consensus predictors after second round were made by a research group and an impartial physician.

RESULTS

The Delphi-process resulted in 19 clinically relevant and applicable predictors based on vital signs and parameters (respiratory rate, saturation, dyspnoea, systolic blood pressure, pulse rate, abnormal electrocardiogram, altered mental state and temperature), biochemical tests (serum c-reactive protein, serum bicarbonate, serum lactate, serum pH, serum potassium, glucose, leucocyte counts and serum haemoglobin), objective clinical observations (skin conditions) and subjective clinical observations (pain reported as new or escalating, and relatives' concerns).

CONCLUSION

The Delphi-process led to consensus of 19 potential predictors of clinical deterioration widely accepted as relevant and applicable in emergency departments.

Lactate kinetics in ICU patients using a bolus of 13C-labeled lactate

Background

Plasma lactate concentrations and their trends over time are used for clinical prognosis, and to guide treatment, in critically ill patients. Although heavily relied upon for clinical decision-making, lactate kinetics of these patients is sparsely studied.

Aim

To establish and validate a feasible method to study lactate kinetics in critically ill patients.

Methods

Healthy volunteers (n = 6) received a bolus dose of ¹³C-labeled lactate (20 μmol/kg body weight), and 43 blood samples were drawn over 2 h to determine the decay in labeled lactate. Data was analyzed using non-compartmental modeling calculating rates of appearance (R_a) and clearance of lactate. The area under the curve (AUC) was calculated using a linear-up log-down trapezoidal approach with extrapolation beyond 120 min using the terminal slope to obtain the whole AUC. After evaluation, the same protocol was used in an unselected group of critically ill patients (n = 10).

Results

R_a for healthy volunteers and ICU patients were 12.8 ± 3.9 vs 22.7 ± 11.1 μmol/kg/min and metabolic clearance 1.56 ± 0.39 vs 1.12 ± 0.43 L/min, respectively. ICU patients with normal lactate concentrations showed kinetics very similar to healthy volunteers. Simulations showed that reducing the number of samples from 43 to 14 gave the same results. Our protocol yielded results on lactate kinetics very similar to previously published data using other techniques.

Conclusion

This simple and user-friendly protocol using an isotopically labeled bolus dose of lactate was accurate and feasible for studying lactate kinetics in critically ill ICU patients.

Trial registration

ANZCTR, ACTRN12617000626369, registered 8 March 2017. https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372507&isReview=true

Triage and flow management in sepsis

Background

Sepsis is a major public health problem, with a growing incidence and mortality rates still close to 30% in severe cases. The speed and adequacy of the treatment administered in the first hours of sepsis, particularly access to intensive care, are important to reduce mortality. This study compared the triage strategies and intensive care rationing between septic patients and patients with other indications of intensive care. This study included all patients with signs for intensive care, enrolled in the intensive care management system of a Brazilian tertiary public emergency hospital, from January 1, 2010, to December 31, 2016. The intensivist periodically evaluated the requests, prioritizing them according to a semi-quantitative scale. Demographic data, Charlson Comorbidity Index (CCI), Sequential Organ Failure Assessment (SOFA), and quick SOFA (qSOFA), as well as surgical interventions, were used as possible confounding factors in the construction of incremental logistic regression models for prioritization and admission to intensive care outcomes.

Results

The study analyzed 9195 ICU requests; septic patients accounted for 1076 cases (11.7%), 293 (27.2%) of which were regarded as priority 1. Priority 1 septic patients were more frequently hospitalized in the ICU than nonseptic patients (52.2% vs. 34.9%, p <  0.01). Septic patients waited longer for the vacancy, with a median delay time of 43.9 h (interquartile range 18.2–108.0), whereas nonseptic patients waited 32.5 h (interquartile range 11.5–75.8)—p <  0.01. Overall mortality was significantly higher in the septic group than in the group of patients with other indications for intensive care (72.3% vs. 39.8%, p <  0.01). This trend became more evident after the multivariate analysis, and the mortality odds ratio was almost three times higher in septic patients (2.7, 2.3–3.1).

Conclusion

Septic patients had a lower priority for ICU admission and longer waiting times for an ICU vacancy than patients with other critical conditions. Overall, this implied a 2.7-fold increased risk of mortality in septic patients.

Predicting Prolonged Intensive Care Unit Stay Among Patients With Sepsis-Induced Hypotension

BACKGROUND

Sepsis risk stratification tools typically predict mortality, although stays in the intensive care unit (ICU) of 24 hours or longer may be more clinically relevant for emergency department disposition.

OBJECTIVE

To explore predictors of ICU stay of 24 hours or longer among infected, hypotensive emergency department patients.

METHODS

A secondary analysis of 2 prospective, observational studies of adult patients with severe sepsis or an infection with a systolic blood pressure less than 90 mm Hg in 3 urban, academic emergency departments was performed. Patients with hypotension and infection were included. Patients with emergency department intubation, vasopressor administration, and/or death were excluded. The primary outcome was ICU stay of 24 hours or longer or death in less than 24 hours. Multivariable logistic regression was used to predict ICU stay of 24 hours or longer.

RESULTS

Of 233 patients, 108 (46.4%) had ICU stays of 24 hours or longer. History of heart failure (odds ratio, 3.6; 95% CI, 1.5-8.3), bicarbonate level less than 20 mEq/L (odds ratio, 2.0; 95% CI, 1.1-3.8), respiratory rate greater than 20/min (odds ratio, 2.0; 95% CI, 1.1-3.7), and creatinine level greater than 2.0 mg/dL (odds ratio, 3.6; 95% CI, 1.9-6.7) were independent predictors of ICU stay of 24 hours or longer (area under curve, 0.74). The presence of 1 of these factors predicted ICU stay of 24 hours or longer (area under curve, 0.74) with 82.4% sensitivity and 49.6% specificity.

CONCLUSIONS

These exploratory results show that heart failure, bicarbonate level of less than 20 mEq/L, tachypnea, or creatinine level greater than 2.0 mg/dL increases the likelihood of an ICU stay of 24 hours or longer among infected, hypotensive emergency department patients.

Association of Clinical Hypoperfusion Variables With Lactate Clearance and Hospital Mortality

BACKGROUND

Lactate has shown utility in assessing the prognosis of patients admitted to the hospital with confirmed or suspected shock. Some findings of the physical examination may replace it as screening tool. We have determined the correlation and association between clinical perfusion parameters and lactate at the time of admission; the correlation between the change in clinical parameters and lactate clearance after 6 and 24 h of resuscitation; and the association between clinical parameters, lactate, and mortality.

METHODS

Prospective cohort study of adult patients hospitalized in the emergency room with infection, polytrauma, or other causes of hypotension. We measured serum lactate, capillary refill time, shock index, and pulse pressure at 0, 6, and 24 h after admission. A Spearman's correlation was performed between clinical variables and lactate levels, as well as between changes in clinical parameters and lactate clearance. The operative characteristics of these variables were determined by area under the receiver operating characteristic curve analysis and the association between lactate, clinical variables, and mortality through logistic regression.

RESULTS

A total of 1,320 patients met the inclusion criteria, 66.7% (n = 880) confirmed infection, 19% (n = 251) polytrauma, and 14.3% (n = 189) another etiology. No significant correlation was found between any clinical variable and lactate values (r < 0.28). None of the variable had an adequate discriminatory capacity to detect hyperlactatemia (AUC < 0.62). In the multivariate model, lactate value at admission was the only variable independently associated with mortality (OR 1.2; 95% CI = 1.1-1.1).

CONCLUSIONS

Among patients with hypoperfusion risk or shock, no correlation was found between clinical variables and lactate. Of the set of parameters collected, lactate at admission was the only independent marker of mortality.

Lactate on emergency department arrival as a predictor of in-hospital mortality in necrotizing fasciitis: a retrospective study

Background

Hyperlactatemia is known to be associated with adverse outcome in critical illness. In this study, we attempted to identify if hyperlactatemia on emergency department (ED) arrival is a reliable predictor for in-hospital mortality in necrotizing fasciitis (NF) patients.

Method

A prospective cohort study of hospitalized patients with NF was conducted in two tertiary teaching hospitals in Taiwan between March 2010 and March 2018. Blood samples were collected in the ED upon arrival, and the lactate levels were determined. Sequential organ failure assessment (SOFA) scores were calculated during the first 24 h after admission. All collected data were statistically analyzed.

Result

Of the 707 NF patients, 40 (5.66%) died in the hospital. The median (interquartile range) blood lactate level in all NF patients was 3.6 mmol/l (2.2–4.8). The blood lactate level upon ED arrival was significantly associated with mortality (odds ratio [OR] = 1.35; 95% confidence interval [CI], 1.30–1.46; P < 0.001), even after adjustment for age and SOFA score (OR = 1.27; P < 0.001). Multivariate regression analysis showed that a high blood lactate level (OR = 1.17; 95% CI, 1.07–1.29; P = 0.001) and a high SOFA score (OR = 1.15; 95% CI, 1.11–1.20; P < 0.001) were independent risk factors for in-hospital mortality in NF. Blood lactate achieved an area under-the-receiver-operating-characteristic curve (AUC) of 0.79 (P < 0.001) for predicting mortality that was similar to that of SOFA score (AUC = 0.82; P < 0.001). Blood lactate displayed a sensitivity of 62% and a specificity of 86% in predicting mortality at the optimal cutoff value of 5.80 mmol/l.

Conclusion

In necrotizing fasciitis patients, hyperlactatemia on ED arrival is independently associated with in-hospital mortality. NF patients with hyperlactatemia on ED arrival should be closely monitored for signs of deterioration and consider early and aggressive intervention to prevent mortality.

Early Lactate Dynamics in Critically Ill Non-Traumatic Patients in a Resuscitation Room of a German Emergency Department (OBSERvE-Lactate-Study)

BACKGROUND

Management of critically ill non-trauma patients in the resuscitation room of an emergency department (ED) is very challenging, and it is difficult to identify patients with a higher risk of death. Previous studies have shown that lactate indices can predict survival for selected diseases and syndromes.

OBJECTIVE

As reported for other patient populations, we set out to determine whether admission lactate or lactate dynamics (LD) within 24 h can predict 30-day mortality in unselected critically ill non-traumatic patients.

METHODS

In this retrospective study over a 1-year period, admission lactate, time weighted average lactate (Lac_TW) and LD of all critically ill adult patients admitted from ED to intensive care unit were analyzed. A linear regression model was implemented to estimate lactate data 1 h after admission.

RESULTS

The admission lactate, Lac_TW, and LD within 24 h were analyzed from 392 critically ill patients. The overall 30-day mortality rate was around 29%. Admission lactate (4.1 ± 4.0 mmol/L vs. 6.6 ± 6.1 mmol/L; p < 0.01) and Lac_TW (1.8 ± 1.7 mmol/L vs. 4.1 ± 4.8 mmol/L; p < 0.01) were different between survivors and non-survivors. LD between survivors and non-survivors did not differ at 1 h, 6 h, 12 h, or 24 h. After excluding patients with out-of-hospital or in-hospital cardiac arrest during resuscitation room management, admission lactate and LD between survivors and non-survivors did not differ at 1 h, 12 h, and 24 h. LD at 6 h (44% ± 42% vs. 33% ± 58%; p = 0.042) and Lac_TW (1.7 ± 1.6 mmol/L vs. 2.6 ± 3.0 mmol/L; p < 0.01) did differ.

CONCLUSIONS

In critically ill ED patients initially requiring treatment in a resuscitation room setting, LD at 6 h and Lac_TW may predict their survival beyond 30 days. These findings need to be confirmed in a prospective study design.

The role of temperature in the detection and diagnosis of neutropenic sepsis in adult solid tumour cancer patients receiving chemotherapy

PURPOSE

The primary aim of this study was to examine the value of temperature as a diagnostic and prognostic indicator of infection and sepsis in neutropenic patients. A secondary aim was to gain insight into the presenting symptoms reported by these patients at home or on their initial admission assessment.

METHODS

A cohort study was carried out using a case note review of 220 emergency admissions to a regional cancer centre. All participants were neutropenic and were diagnosed with infection on admission. The main outcome measures were relationships between Early Warning Scores and temperature values at home, on admission and during the hospital stay.

RESULTS

22% of patients who became acutely unwell did not have a fever. Pearson correlations showed only small associations between highest temperature value at any time point and highest early warning scores (r(202) = 0.176, P = .012). Temperature at home (B = 0.156, P = .336) and temperature on admission (B = 0.200, P = .052) did not predict highest Early Warning Scores.

CONCLUSIONS

Body temperature is not a consistently reliable diagnostic or prognostic indicator for outcomes in patients with neutropenia and symptoms of infection. It can assist with early presentation and recognition of infection in many neutropenic patients. However, over-reliance on temperature risks missing the opportunity for early detection and treatment.

Reconsidering lactate as a sepsis risk biomarker

Objectives

There has been renewed interest in lactate as a risk biomarker in sepsis and septic shock. However, the ability of the odds ratio (OR) and change in the area under the receiver operator characteristic curve (AUC-ROC) to assess biomarker added-value has been questioned.

Design, setting and participants

A sepsis cohort was identified from the ICU database of an Australian tertiary referral hospital using APACHE III diagnostic codes. Demographic information, APACHE III scores, 24-hour post-admission patient lactate levels, and hospital mortality were accessed.

Measurements and main results

Hospital mortality was modelled using a base predictive logistic regression model and sequential addition of admission lactate, lactate clearance ([lactate^admission—lactate^final]/lactate^admission), and area under the lactate-time curve (LTC). Added-value was assessed using lactate index OR; AUC-ROC difference (base-model versus lactate index addition); net (mortality) reclassification index (NRI; range -2 to +2); and net benefit (NB), the number of true positives per patient adjusted for the number of false positives. The data set comprised 717 patients with mean(SD) age and APACHE III score 61.1(16.5) years and 68.3(28.2) respectively; 59.2% were male. Admission lactate was 2.3(2.5) mmol/l; with lactate of ≥ 4 mmol/L (37% hospital mortality) in 17% and patients with lactate < 4 mmol/L having 18% hospital mortality. The admission base-model had an AUC-ROC = 0.81 with admission lactate OR = 1.127 (95%CI: 1.038, 1.224), AUC-ROC difference of 0.0032 (-0.0037, 0.01615; P = 0.61), and NRI 0.240(0.030, 0.464). The over-time model had an AUC-ROC = 0.86 with (i) clearance OR = 0.771, 95%CI: 0.578, 1.030; P = 0.08; AUC-ROC difference 0.001 (-0.003, 0.014; P = 0.78), and NRI 0.109(-0.193, 0.425) and (ii) LTC OR = 0.997, 95%CI: 0.989, 1.005, P = 0.49; AUC-ROC difference 0.004 (-0.002, 0.004; P = 0.34), and NRI 0.111(-0.222, 0.403). NB was not incremented by any lactate index.

Conclusions

Lactate added-value assessment is dependent upon the performance of the underlying predictive model and should incorporate risk reclassification and net benefit measures.

Diagnosing sepsis - The role of laboratory medicine

Sepsis is the host response to microbial pathogens resulting in significant morbidity and mortality. An accurate and timely diagnosis of sepsis allows prompt and appropriate treatment. This review discusses laboratory testing for sepsis because differentiating systemic inflammation from infection is challenging. Procalcitonin (PCT) is currently an FDA approved test to aid in the diagnosis of sepsis but with questionable efficacy. However, studies support the use of PCT for antibiotic de-escalation. Serial lactate measurements have been recommended for monitoring treatment efficacy as part of sepsis bundles. The 2016 sepsis consensus definitions include lactate concentrations >2mmol/L (>18mg/dL) as part of the definition of septic shock. Also included in the 2016 definitions are measuring bilirubin and creatinine to determine progression of organ failure indicating worse prognosis. Hematologic parameters, including a simple white blood cell count and differential, are frequently part of the initial sepsis diagnostic protocols. Several new biomarkers have been proposed to diagnose sepsis or to predict mortality, but they currently lack sufficient sensitivity and specificity to be considered as stand-alone testing. If sepsis is suspected, new technologies and microbiologic assays allow rapid and specific identification of pathogens. In 2016 there is no single laboratory test that accurately diagnoses sepsis.