Validation of a point-of-care capillary lactate measuring device (Lactate Pro 2).

Background: The measurement of lactate in emergency medical services has the potential for earlier detection of shock and can be performed with a point-of-care handheld device. Validation of a point-of-care handheld device is required for prehospital implementation. Aim: The primary aim was to validate the accuracy of Lactate Pro 2 in healthy volunteers and in haemodynamically compromised intensive care patients. The secondary aim was to evaluate which sample site, fingertip or earlobe, is most accurate compared to arterial lactate. Methods: Arterial, venous and capillary blood samples from fingertips and earlobes were collected from intensive care patients and healthy volunteers. Arterial and venous blood lactate samples were analysed on a stationary hospital blood gas analyser (ABL800 Flex) as the reference device and compared to the Lactate Pro 2. We used the Bland-Altman method to calculate the limits of agreement and used mixed effect models to compare instruments and sample sites. A total of 49 intensive care patients with elevated lactate and 11 healthy volunteers with elevated lactate were included. Results: There was no significant difference in measured lactate between Lactate Pro 2 and the reference method using arterial blood in either the healthy volunteers or the intensive care patients. Capillary lactate measurement in the fingertip and earlobe of intensive care patients was 47% (95% CI (29% to 68%), p<0.001) and 27% (95% CI (11% to 45%), p<0.001) higher, respectively, than the corresponding arterial blood lactate. In the healthy volunteers, we found that capillary blood lactate in the fingertip was 14% higher than arterial blood lactate (95% CI (4% to 24%), p= 0.003) and no significant difference between capillary blood lactate in the earlobe and arterial blood lactate. Conclusion: Our results showed that the handheld Lactate Pro 2 had good agreement with the reference method using arterial blood in both intensive care patients and healthy volunteers. However, we found that the agreement was poorer using venous blood in both groups. Furthermore, the earlobe may be a better sample site than the fingertip in intensive care patients.

Lactate arterial-central venous gradient among COVID-19 patients in ICU: a potential tool in the clinical practice

ABSTRACTObjectiveIn physiological conditions arterial blood lactate concentration is equal or lower than central venous. The aim of this study was to explore if the COVID-19 induced lung cells damage was mirrored by an arterial lactatemia higher than the central venous one; then if the administration of immunosuppressant drugs (i.e. canakinumab) could normalize such abnormal lactate a-cv difference.MethodsProspective cohort study started on March 25th 2020 for a duration of 10 days, enrolling 21 patients affected by severe COVID-19 pneumonia undergoing mechanical ventilation consecutively admitted to the ICU of the Rimini Hospital, Italy.Arterial and central venous blood samples were contemporary collected to calculate the difference between arterial and central venous lactate (Delta a-cv lactate) concentration within 24 h from tracheal intubation (T0), and 24 hours after canakinumab administration (T1).ResultsAt the T0 19/21 (90.5%) patients showed a pathologic Delta a-cv lactate (median 0.22 mmol/L; IQR 0.07–0.36), suggesting severe inflammation. In the 13 patients undergoing canakinumab administration, at the T1 Delta a-cv lactate decreased in 92.3% of cases, being the decrease statistically significant (T0: median 0.15, IQR 0.07–0.25 mmol/L; T1: median −0.01, IQR 0.09–0.04 mmol/L; p=0.002).ConclusionA reversed Delta a-cv lactate is likely to be one of the effects of COVID-19 related cytokine storm, that could reflect a derangement in the lung cells mitochondrial metabolism induced by inflammation or other uncoupling mediators. Delta a-cv lactate decrease may reflect the anti-inflammatory activity of canakinumab. Our preliminary findings need to be confirmed by larger outcome studies.

Blood Lactate Is a Useful Indicator for the Medical Emergency Team

Lactate has been thoroughly studied and found useful for stratification of patients with sepsis, in the Intensive Care Unit, and trauma care. However, little is known about lactate as a risk-stratification marker in the Medical Emergency Team- (MET-) call setting. We aimed to determine whether the arterial blood lactate level at the time of a MET-call is associated with increased 30-day mortality. This is an observational study on a prospectively gathered cohort at a regional secondary referral hospital. All MET-calls during the two-year study period were eligible. Beside blood lactate, age and vital signs were registered at the call. Among the 211 calls included, there were 64 deaths (30.3%). Median lactate concentration at the time of the MET-call was 1.82 mmol/L (IQR 1.16–2.7). We found differences between survivors and nonsurvivors for lactate and oxygen saturation, a trend for age, but no significant correlations between mortality and systolic blood pressure, respiratory rate, and heart rate. As compared to normal lactate (<2.44 mmol/L), OR for 30-day mortality was 3.54 (p<0.0006) for lactate 2.44–5.0 mmol/L and 4.45 (p<0.0016) for lactate > 5.0 mmol/L. The present results support that immediate measurement of blood lactate in MET call patients is a useful tool in the judgment of illness severity.

High serum lactate level may predict death within 24 hours

Background: Unexpected death within 24 hours of admission is a real challenge for the clinician in the emergency room. How to diagnose these patients and the right approach to prevent sudden death with 24 hours is still an enigma. The aims of our study were to find the independent factors that may affect the clinical outcome in the first 24 hours of admission to the hospital.Methods: We performed a retrospective study defining unexpected death within 24 hours of admission in our Department of Medicine in the last 6 years. We found 43 patients who died within 24 hours of admission, and compared their clinical and biochemical characteristics to 6055 consecutive patients who were admitted in that period of time and did not die within the first 24 hours of admission. The parameters that were used include gender, age, temperature, clinical and laboratory criteria for SIRS, arterial blood lactate, and arterial blood pH.Results: Most of the patients who died within 24 hours had sepsis with SIRS. These patients were older (78.6±14.7 vs. 65.2±20.2 years [p<.0001]), had higher lactate levels (8.0±4.8 vs. 2.1±1.8mmol/L[p<.0001]), and lower pH (7.2±0.2 vs. 7.4±0.1 [p<.0001]). Logistic regression analysis found that lactate was the strongest independent parameter to predict death within 24 hours of admission (OR1.366 [95% CI 1.235-1.512]), followed by old age (OR 1.048 [95% CI 1.048-1.075] and low arterial blood pH (OR 0.007 [CI <0.001-0.147]). When gender was analyzed, pH was not an independent variable in females (only in males).Conclusions: The significant independent variable that predicted death within 24 hours of admission was arterial blood lactate level on admission. Older age was also an independent variable; low pH affected only males, but was a less dominant variable. We suggest use of arterial blood lactate level on admission as a bio-marker in patients with suspected sepsis admitted to the hospital for risk assessment and prediction of death within 24 hours of admission.

Abstract 339: Capillary Transmitted Light Intensity for the Monitoring of Tissue Perfusion: CLIP Study

Background: We developed a new device for quantifying capillary refill time (CRT) by applying the pulse oximeter principle, and reported the excellent correlation between quantitative CRT (Q-CRT) and tissue hypoperfusion status as represented by arterial blood lactate levels in critically ill patients in the pilot study. Methods: Diagnostic accuracy study was undergone in ICU of a tertiary emergency medical center. While the pulse oxygen saturation sensor was placed on the finger of the patients, transmitted light intensity was measured with a pulse oximeter (OLV-3100, Nihon Kohden Corp., Japan) before start and during compression of the finger. Correlation between delta Ab, defined as the absorbance of light intensity of infra-red (A-ir) minus that of red (A-r), and arterial blood lactate level was analyzed. Results: The delta Ab was analyzed a total of 69 waveforms in 23 patients. The sensitivity, specificity, positive predictive value, and negative predictive value of the delta Ab less than 0.06 for predicting a lactate level more than 2.0 mmol/l were 100%, 93%, 89%, 100%, respectively. Conclusions: The delta Ab was well correlated to high level of blood lactate level in critically ill patients. Further study will confirm to place the delta Ab as one of non-invasive predictors of tissue perfusion status.