Capillary Lactate Research Articles

Dexmedetomidine versus propofol or midazolam in patients with abdominal sepsis regarding inflammatory response and capillary leak

ABSTRACT Background Abdominal sepsis patients suffer from profound intravascular fluid deficit due to concomitant inflammatory response and capillary leakage. It is reported that anti-inflammatory properties of sedative agents can control inflammatory cascade in many experimental septic conditions. We aimed to investigate the best sedative drug for inflammatory responses and capillary leak in patients with abdominal sepsis. Methods In this prospective randomized study, 60 patients with abdominal sepsis who underwent abdominal surgery and required post-operative sedation and mechanical ventilation were randomized into 3 groups in a 1:1:1 ratio. Group D (sedated with dexmedetomidine), group P (sedated with propofol), and group M (sedated with midazolam). This study was held in intensive care units of Assiut University Hospitals with primary outcome was serum IL-6 and IL-1β. Secondary outcomes were capillary leak index, lactate clearance, vasopressor requirements, total intake, total output, and fluid balance. Results Dexmedetomidine significantly reduced levels of IL-6 and IL-1β through 48 hours compared to both midazolam and propofol. Dexmedetomidine caused a significant decline in capillary leak index (p < 0.05) through 48 hours and significant higher lactate clearance (p = 0.03) in first 24 hours compared to both midazolam and propofol. Dexmedetomidine group had a significantly lower intake in first 24 hours and comparable vasopressor requirements through 48 hours. Dexmedetomidine group had a significantly higher output, lower serum creatinine levels and lower positive fluid balance compared to propofol and midazolam. Conclusions Dexmedetomidine reduced inflammatory response and capillary leak in mechanically ventilated patients with abdominal sepsis with better lactate clearance and less fluid intake.

Glucose and Fructose Supplementation and Their Acute Effects on Anaerobic Endurance and Resistance Exercise Performance in Healthy Individuals: A Double-Blind Randomized Placebo-Controlled Crossover Trial.

The effects of glucose, fructose and a combination of these on physical performance have been subject of investigation, resulting in diverse findings. The aim of this study was to investigate how an individualized amount of glucose, fructose, and a combination of these compared to placebo (sucralose) alter endurance performance on a cycle ergometer, lower and upper body resistance exercise performance at individualized thresholds in healthy young individuals. A total of 16 healthy adults (9 females) with an age of 23.8 ± 1.6 years and a BMI of 22.6 ± 1.8 kg/m2 (body mass (BM) 70.9 ± 10.8 kg, height 1.76 ± 0.08 m) participated in this study. During the screening visit, the lactate turn point 2 (LTP2) was defined and the weights for chest-press and leg-press were determined. Furthermore, 30 min prior to each exercise session, participants received either 1 g/kg BM of glucose (Glu), 1 g/kg BM of fructose (Fru), 0.5 g/kg BM of glucose/fructose (GluFru) (each), or 0.2 g sucralose (placebo), respectively, which were dissolved in 300 mL of water. All exercises were performed until volitional exhaustion. Time until exhaustion (TTE) and cardio-pulmonary variables were determined for all cycling visits; during resistance exercise, repetitions until muscular failure were counted and time was measured. During all visits, capillary blood glucose and blood lactate concentrations as well as venous insulin levels were measured. TTE in cycling was 449 ± 163 s (s) (Glu), 443 ± 156 s (Fru), 429 ± 160 s (GluFru) and 466 ± 162 s (Pla) (p = 0.48). TTE during chest-press sessions was 180 ± 95 s (Glu), 180 ± 92 s (Fru), 172 ± 78 s (GluFru) and 162 ± 66 s (Pla) (p = 0.25), respectively. Pre-exercise supplementation of Glu, Fru and a combination of these did not have an ergogenic effect on high-intensity anaerobic endurance performance and on upper and lower body moderate resistance exercise in comparison to placebo.

Abstract 131: Perceived Exertion And Physical Demand Of Performing 10-minutes Of Compression-only CPR

Cardiopulmonary resuscitation (CPR) is physically demanding and must also be performed under emotional distress. Most cardiac arrests (CA) occur at home, making it likely that only one rescuer is available to perform CPR until emergency medical services (EMS) or other lay rescuers arrive. We performed a study to quantify the physical exertion required of lay-providers performing compression-only CPR for 10 minutes both with (WFB) and without (WOFB) real-time CPR quality feedback. We recruited healthy, CPR certified lay individuals to perform 10-minute rounds of CPR on two occasions: once WFB and once WOFB. We collected heart rate (HR), oxygen consumption (VO 2 ), and rating of perceived exertion (RPE) at baseline and throughout each round of CPR and collected capillary lactate and blood pressures pre- and post-CPR. We used Kruskal Wallis, Wilcoxon signed rank and rank sum tests to compare changes in measures during CPR. Participants were 15 females and 11 males, age 25 (IQR 22-37). All measures except for diastolic blood pressure, significantly changed over time. Systolic blood pressure increased both WFB (mean difference (MD) 8mmHg; 95% CI 12-5) and WOFB (MD 8mmHg; 95% CI 12-3). VO 2 and HR increased over time, but peak VO 2 and HR did not differ by group. RPE significantly increased WFB and WOFB (WFB MD 8; 95% CI 10-7; WOFB MD 8; 95% CI 9-7) WFB and WOFB, with females reporting a higher RPE immediately post-CPR WFB than males (MD 2; 95% CI 5-1). Lactate increased from baseline immediately post (WFB MD 2.3mmol/L; 95% CI 0.9-3.7; WOFB MD 1.8mmol/L; 95%CI 2.6-1) and 5-minutes post CPR (WFB MD 0.8mmol/L; 95% CI 2.3-0.7; WOFB MD2.1 mmol/L; 95% CI 0.9-3.3). CPR produces subjective and objective signs of strenuous exertion in both men and women. The presence of feedback does not alter physiologic response to prolonged CPR. However, females reported higher RPEs when performing CPR WFB, despite no significant difference in physiologic response.

High Dose of Acute Normobaric Hypoxia Does Not Adversely Affect Sprint Interval Training, Cognitive Performance and Heart Rate Variability in Males and Females.

Simple SummarySprint interval training (SIT) is a feasible and time-efficient alternative to classical endurance training that has gained popularity among athletes because of its ability to elicit physiological and cardiorespiratory adaptations in a shorter amount of time than traditional endurance training. Further, popular altitude/hypoxic training techniques include intermittent hypoxic training, in which athletes exercise at submaximal levels under simulated hypoxia while living at sea level (normoxia). Hypoxic exercise is likely a more potent stimulant to upregulate muscle factors (e.g., mitochondrial biogenesis, oxidative, and glycolytic enzymes) than similar normoxic exercise. However, SIT in hypoxia may disturb acute performance indices during sprint intervals. Hypoxia may also impair cognitive function. Acute hypoxia may decrease cognitive performance in areas such as memory and executive functioning. Moreover, males and females may have distinct athletic performance responses to SIT and hypoxia. However, to date, there is no study that has investigated the effects of different doses of acute normobaric hypoxia on SIT and cognitive performance, nor has there been research investigating potential sex-based differences.Although preliminary studies suggested sex-related differences in physiological responses to hypoxia, the effects of sex on sprint interval training (SIT) performance in different degrees of hypoxia are largely lacking. The aim of this study was to examine the acute effect of different doses of normobaric hypoxia on SIT performance as well as heart rate variability (HRV) and cognitive performance (CP) in amateur-trained team sport players by comparing potential sex differences. In a randomized, double-blind, crossover design, 26 (13 females) amateur team-sport (football, basketball, handball, rugby) players completed acute SIT (6 × 15 s all-out sprints, separated with 2 min active recovery, against a load equivalent to 9% of body weight) on a cycle ergometer, in one of four conditions: (I) normoxia without a mask (FiO2: 20.9%) (CON); (II) normoxia with a mask (FiO2: 20.9%) (NOR); (III) moderate hypoxia (FiO2: 15.4%) with mask (MHYP); and (IV) high hypoxia (FiO2: 13.4%) with mask (HHYP). Peak (PPO) and mean power output (MPO), HRV, heart rate (HR), CP, capillary lactate (BLa), and ratings of perceived exertion (RPE) pre- and post-SIT were compared between CON, NOR, MHYP and HHYP. There were no significant differences found between trials for PPO (p = 0.55), MPO (p = 0.44), RPE (p = 0.39), HR (p = 0.49), HRV (p > 0.05) and CP (response accuracy: p = 0.92; reaction time: p = 0.24). The changes in MP, PP, RPE, HR, CP and HRV were similar between men and women (all p > 0.05). While BLa was similar (p = 0.10) between MHYP and HHYP trials, it was greater compared to CON (p = 0.01) and NOR (p = 0.01), without a sex-effect. In conclusion, compared to normoxia, hypoxia, and wearing a mask, have no effect on SIT acute responses (other than lactate), including PP, MP, RPE, CP, HR, and cardiac autonomic modulation either in men or women.

Experimental evaluation of laparoscopic laser speckle contrast imaging to visualize perfusion deficits during intestinal surgery

BackgroundIschemia at the site of an intestinal anastomosis is one of the most important risk factors for anastomotic leakage (AL). Consequently, adequate intestinal microperfusion is essential for optimal tissue oxygenation and anastomotic healing. As visual inspection of tissue viability does not guarantee an adequate objective evaluation of intestinal microperfusion, surgeons are in dire need of supportive tools to decrease anastomotic leakage after colorectal surgery.MethodsIn this feasibility study, laparoscopic laser speckle contrast imaging (LSCI) was used to evaluate intestinal microperfusion in an experimental ischemic bowel loop model. Both large and small ischemic loops were created from the small intestine of a pig; each loop was divided into 5 regions of interest (ROI) with varying levels of ischemia. Speckle contrast and local capillary lactate (LCL) was measured in all ROIs.ResultsBoth real-time visualization of intestinal microperfusion and induced perfusion deficits was achieved in all bowel loops. As a result, the emergence of regions of intestinal ischemia could be predicted directly after iatrogenic perfusion limitation, whereas without LSCI signs of decreased intestinal viability could only be seen after 30 minutes. Additionally, a significant relation was found between LCL and LSCI.ConclusionIn conclusion, LSCI can achieve real-time intraoperative visualization of intestinal microperfusion deficits, allowing for accurate prediction of long-term postoperative ischemic complications. With this revealing capacity, LSCI could potentially facilitate surgical decision-making when constructing intestinal anastomoses in order to mitigate ischemia-related complications such as AL.

Adequate exercise response at artificial altitude in Fontan patients

PurposeFor Fontan-palliated patients, altitude exposure is still a part of discussion since the extent of hypoxic pulmonary vasoconstriction potentially resulting in decreasing cardiac output (Qc), especially during physical exercise, is still unclear. We investigated the effects of normobaric hypoxia (15.2% O2) simulating 2,500 m above sea level on cardiopulmonary and metabolic parameters and the benefit of daily physical activity (PA) on hypoxic exercise capacity.MethodsA total of 21 Fontan patients (14–31 years) and 20 healthy controls performed cardiopulmonary exercise tests on a bicycle ergometer in normoxia and hypoxia until subjective exhaustion, measuring capillary lactate (cLa) every 2 min. In between, participants underwent an activity tracking over 5 days with a triaxial accelerometer.ResultsHypoxic exercise was well tolerated by Fontan patients, and no adverse clinical events were observed. Fontan patients showed reduced physical capacity under both conditions compared to controls (63% normoxia, 62% hypoxia), but the relative impairment due to hypoxia was similar for both (≈10%). Up to workloads of 2 W/kg oxygen uptake (O2) and heart rate (HR) developed similarly in patients and controls. cLa increased faster in relation to workload in Fontan patients, but remained significantly lower at peak workload (normoxia 3.88 ± 1.19 mmol/l vs. 7.05 ± 2.1 mmol/l; hypoxia 4.01 ± 1.12 mmol/l vs. 7.56 ± 1.82 mmol/l). Qc was diminished but could be increased similar to controls. Fontan patients with higher PA levels showed a higher O2peak in hypoxia.ConclusionExercise during short-time artificial altitude exposure seems to be safe for young Fontan patients. Further studies are needed to validate longer exposure under real conditions. O2, HR, and Qc might not be a limiting factor for exercise until workloads of 2 W/kg. Higher daily PA levels might improve physical capacity under altitude conditions.

Impact of probiotic supplementation on exercise endurance among non-elite athletes: study protocol for a randomized, placebo-controlled, double-blind, clinical trial

BackgroundSome probiotics appear to improve athletic performance, endurance, and recovery after intense exercise. Other formulations may provide performance-related benefits via immune and gastrointestinal functions in athletic individuals. However, few formulations have been studied for both types of effects among non-elite athletes. The primary objective of this study is to assess the ergogenic effects of a probiotic on high-intensity endurance running performance in non-elite runners. Secondary objectives include assessment of perceived exertion, blood chemistry, immune and stress biomarkers, cold and flu symptoms, and gastrointestinal health after the probiotic intervention.MethodsThis 9-week randomized, placebo-controlled, double-blind, parallel trial will assess the ergogenic effects of a probiotic (5 billion colony-forming units/day, for 6 weeks) in healthy, non-elite runners (N=32; 18–45 years). Participants will be monitored via daily and weekly questionnaires during the 2-week pre-baseline, 6-week intervention, and 1-week washout. Questionnaires will inquire about activity, muscle soreness, gastrointestinal symptoms, cold and flu symptoms, stool form and frequency, and adverse events. During the pre-baseline visit, maximal oxygen uptake (V̇O2 max) is assessed to set appropriate individualized workload settings for the treadmill time-to-exhaustion endurance tests. These time-to-exhaustion endurance running tests will be completed at an intensity of 85% VO2max at baseline and final visits. During these tests, self-perceived exercise effort will be rated via the Borg Rating of Perceived Exertion scale and finger sticks assessing capillary blood glucose and lactate concentrations will be collected every 3 min. Additional questionnaires will assess diet and motivation to exercise. Body composition will be assessed using air displacement plethysmography at the baseline and final visits. Hypotheses will be tested using two-sided tests, and a linear model and with a type I error rate of α=0.05. Primary and secondary outcomes will be tested by comparing results between the intervention groups, adjusting for baseline values.DiscussionThese results will build evidence documenting the role of probiotics on running endurance performance and physiological responses to exercise in non-elite athletes. Understanding the potential mechanisms of probiotic effects and how they mitigate the intestinal or immune discomforts caused by running could provide additional strategy means to help runners improve their performance.Trial registration numberClinicalTrials.govNCT04588142. Posted on October 19, 2020.Protocol version: July 2, 2021, version 1.2

Exercise Oximetry Correlates Better With Exercise-Induced Lactate Increase, than Ankle Brachial Index or Walking Time, in Vascular Claudicants.

In claudication, the correlation between walking-induced biomarkers and indices of clinical severity (e.g., walking distance or ankle brachial index (ABI)), is fair. We hypothesized that a correlation would be observed between the clinical estimation of ischemia severity with exercise transcutaneous oximetry (Ex-TcpO2) and lactate increase. A prospective study was performed among 377 patients with arterial claudication. We recorded age, sex, ABI, body mass index (BMI), systolic arterial blood pressure (SBP), and glycemia. Capillary blood lactate was measured at rest and 3min after a constant load treadmill test. We recorded maximum walking time (MWT), heart rate (HRmax), the sum of minimal decrease from oxygen values for buttocks, thighs and calves Ex-TcpO2 (DROPmin), as well as the amplitude of chest-TcpO2 decrease. A multilinear regression model was used to assess the variables associated with lactate increase. BMI, SBP, HRmax, the amplitude of decrease in chest-TcpO2 and DROPmin, but not age, sex, ABI, MWT, diabetes mellitus nor glycemia, were significantly associated to lactate increase in the model. Because it accounts for the severity and diffusion of lower-limb exercise-induced ischemia and detects exercise induced hypoxemia, TcpO2 may be preferable to ABI or MWT to estimate the metabolic consequences of walking in claudicants.

Determination of Second Lactate Threshold Using Near-infrared Spectroscopy in Elite Cyclists.

The use of near-infrared spectroscopy could be an interesting alternative to other invasive or expensive methods to estimate the second lactate threshold. Our objective was to compare the intensities of the muscle oxygen saturation breakpoint obtained with the Humon Hex and the second lactate threshold in elite cyclists. Ninety cyclists performed a maximal graded exercise test. Blood capillary lactate was obtained at the end of steps and muscle oxygenation was continuously monitored. There were no differences (p>0.05) between muscle oxygen oxygenation breakpoint and second lactate threshold neither in power nor in heart rate, nor when these values were relativized as a percentage of maximal aerobic power or maximum heart rate. There were also no differences when men and women were studied separately. Both methods showed a highly correlation in power (r=0.914), percentage of maximal aerobic power (r=0.752), heart rate (r=0.955), and percentage of maximum heart rate (r=0.903). Bland-Altman resulted in a mean difference of 0.05±0.27 W·kg-1, 0.91±4.93%, 0.63±3.25 bpm, and 0.32±1.69% for power, percentage of maximal aerobic power, heart rate and percentage of maximum heart rate respectively. These findings suggest that Humon may be a non-invasive and low-cost alternative to estimate the second lactate threshold intensity in elite cyclists.

Prehospital capillary lactate in children differentiates epileptic seizure from febrile seizure, syncope, and psychogenic nonepileptic seizure

PurposeThe aim of the study was to examine prehospital capillary lactate in children as a diagnostic biomarker to differentiate epileptic seizures from febrile seizures, syncope, and psychogenic nonepileptic seizures (PNES). MethodsCapillary lactate concentrations taken in a pediatric prehospital setting within 2 h of the paroxysmal event were compared retrospectively between patients with epileptic seizure, febrile seizure, syncope, and PNES, based on the final diagnosis from the hospitalization report. ResultsOne hundred and two patients were included, 53 (52%) with epileptic seizures, 41 (40%) with febrile seizures, and 8 (8%) with syncope or PNES. Capillary lactate in patients with a final diagnosis of epileptic seizure was significantly increased in comparison to the concentrations in patients with febrile seizure (p < 0.0007) and in comparison to the concentrations in patients with syncope or PNES (p < 0.0204). The area under the ROC-curve was 0.71 (95% CI 0.61–0.80). For a cutoff concentration of prehospital capillary lactate >3.9 mmol/l (Youden index), the sensitivity was 49% and the specificity 92%. ConclusionPrehospital capillary lactate concentrations are a useful tool for differentiating the nature of a paroxysmal event in children.

Comprehensive Evaluation and Determinant of Second Lactate Threshold in Homozygous Sickle Cell Disease

Following respiratory, cardiac and peripheral vascular impairments, Sickle Cell Disease (SCD) patients can experience early second lactate threshold (S2) during low intensity exercise. Through a comprehensive evaluation of exercise parameters we want to assess and find factors associated with an early reached of S2. Homozygous SCD patients were prospectively included in this study. They performed physical exercise with a standardized protocol. Gaz exchange, capillary lactate concentration measurements and echocardiography were performed at baseline and throughout the exercise until S2 was reached. Baseline and exercise data of the bottom and top half of patients in terms of %predicted VO2 at S2 were compared to investigate the determinant of an early S2, adjusted over age, sex and body mass index (BMI). Thirty patients were included (42 ± 12 years old, 50% of female). Bottom half group reached 34,5% ± 5,2 predicted VO2 at S2 (mean %predicted Watt = 32% ± 5,9) while top half group reached 46,2% ± 6,8 predicted VO2 at S2 (mean %predicted Watt = 42,8% ± 9,6) ( Fig. 1 ). Plasmatic hemoglobin concentration was the only baseline parameter associated with a lower %predicted VO2 at S2 (8.1 ± 1 vs. 9.2 ± 1 g/dl, P = 0.007). None of the baseline echocardiographic parameters were associated with a lower %predicted VO2 at S2. Diastolic adaptation through exercise was associated with a better power and VO2 at S2 (ratio S2/baseline of E’lateral wave and E/E’, respectively 1,39 vs. 1,63, P = 0,039 and 1,2 vs. 0,99, P = 0,004) SCD patients with lower hemoglobin and impaired diastolic adaptation through exercise displayed earlier S2, independently of age, sex and BMI. This highlights the great vulnerability of these patients to low metabolic stress. They should benefit from low intensity physical therapy programs.

Is Rating of Perceived Exertion a Valuable Tool for Monitoring Exercise Intensity During Steady-State Conditions in Elite Endurance Athletes?

Rating of perceived exertion (RPE) is a widely used tool to assess subjective perception of effort during exercise. The authors investigated between-subject variation and effect of exercise mode and sex on Borg RPE (6-20) in relation to heart rate (HR), oxygen uptake (VO2), and capillary blood lactate concentrations. A total of 160 elite endurance athletes performed a submaximal and maximal test protocol either during cycling (n = 84, 37 women) or running (n = 76, 32 women). The submaximal test consisted of 4 to 7 progressive 5-minute steps within ∼50% to 85% of maximal VO2. For each step, steady-state HR, VO2, and capillary blood lactate concentrations were assessed and RPE reported. An incremental protocol to exhaustion was used to determine maximal VO2 and peak HR to provide relative (%) HR and VO2 values at submaximal work rates. A strong relationship was found between RPE and %HR, %VO2, and capillary blood lactate concentrations (r = .80-.82, all Ps < .05). The between-subject coefficient of variation (SD/mean) for %HR and %VO2 decreased linearly with increased RPE, from ∼10% to 15% at RPE 8 to ∼5% at RPE 17. Compared with cycling, running induced a systematically higher %HR and %VO2 (∼2% and 5%, respectively, P < .05) with these differences being greater at lower intensities (RPE < 13). At the same RPE, women showed a trivial, but significantly higher %HR and %VO2 than men (<1%, P < .05). Among elite endurance athletes, exercise mode influenced RPE at a given %HR and %VO2, with greater differences at lower exercise intensities. Athletes should manage different tools to evaluate training based on intensity and duration of workouts.

Hydrogen inhalation in rehabilitation program of the medical staff recovered from COVID-19

Active hydrogen inhalation (H(H2O)m) has powerful antioxidant and antiapoptotic effects. In recent years, it has been used in a number of experimental and clinical studies.Aim. To study the safety and effectiveness of inhalation of the “active form of hydrogen” (AFV;(H(H2O)m)) in the rehabilitation program of coronavirus disease 2019 (COVID-19) survivors during the recovery period.Material and methods. This randomized controlled parallel prospective study included 60 COVID-19 survivors with post-COVID-19 syndrome (ICD-10: U09.9) during the recovery period, with clinical manifestations of chronic fatigue syndrome (CFS), who received standard therapy in accordance with the management protocol of patients with CFS (ICD-10: G93.3): physiotherapy and medication therapy with drugs containing magnesium, B vitamins and L-carnitine. The patients were divided into 2 groups. The experimental group (n=30) included patients who received hydrogen inhalation for 90 minutes every day during 10 days (SUISONIA hydrogen inhalation device, Japan). The control group (n=30) consisted of patients who received standard therapy. In both groups, patients were comparable in sex and mean age: in the experimental group — 53 (22; 70) years, in the control group — 51 (25; 70) years. Biological markers of systemic inflammation, oxygen transport, lactate metabolism, intrapulmonary shunting, 6-minute walk test, and vascular endothelial function were determined in all patients on the 1st and 10th days of follow-up.Results. In the experimental group, a decrease in following parameters was revealed: stiffness index (SI), from 8,8±1,8 to 6,8±1,5 (p&lt;0,0001); ALT, from 24,0±12,7 to 20,22±10,61 U/L (p&lt;0,001); venous blood lactate, from 2,5±0,8 to 1,5±1,0 mmol/L (p&lt;0,001); capillary blood lactate, from 2,9±0,8 to 2,0±0,8 mmol/L (p&lt;0,0001); estimated pulmonary shunt fraction (Qs/Qt, Berggren equation, 1942) from 8,98±5,7 to 5,34±3,2 (p&lt;0,01); white blood cells, from 6,64±1,57 to 5,92±1,32 109/L. In addition, we revealed an increase in the refractive index (RI) from 46,67±13,26% to 63,32±13,44% (p&lt;0,0001), minimum blood oxygen saturation (SpO2) from 92,25±2,9 to 94,25±1, 56% (p&lt;0,05), direct bilirubin from 2,99±1,41 to 3,39±1,34 pmol/L (p&lt;0,01), partial oxygen tension (PvO2) from 26,9±5,0 to 34,8±5,6 mm Hg (p&lt;0,0001), venous oxygen saturation (SvO2) from 51,8±020,6 to 61,1±018,1% (p&lt;0,05), partial capillary oxygen tension (PcO2) from 48,7±15,4 to 63,8±21,2 mm Hg (p&lt;0,01), capillary oxygen saturation (ScO2) from 82,2±4,2 to 86,2±4,8% (p&lt;0,01), distance in 6 minute walk test from 429±45,0 to 569±60 m.Conclusion. Inhalation therapy with H(H2O)m in the rehabilitation program of COVID-19 survivors during the recovery period is a safe and highly effective method. Manifestations of silent hypoxemia and endothelial dysfunction decreased, while exercise tolerance increased. As for laboratory tests, a decrease in the white blood cell count, estimated pulmonary shunt fraction and lactate content parameters was revealed.

Blood Lactate AUC Is a Sensitive Test for Evaluating the Effect of Exercise Training on Functional Work Capacity in Patients with Chronic Heart Failure.

Purpose Exercise training is an essential treatment option for patients with chronic heart failure (CHF). However, it remains controversial, which surrogate measures of functional work capacity are most reliable. The purpose of this paper was to compare functional capacity work measured as capillary lactate concentrations area under the curve (AUC) with standard cardiopulmonary exercise testing (CPET) with VO2peak and the 6-minute walk test (6 MWT). Methods Twenty-three patients in New York Heart Association (NYHA) class II/III with left ventricular ejection fraction (LVEF) <35% were randomised to home-based recommendation of regular exercise (RRE) (controls), moderate continuous training (MCT) or aerobic interval training (AIT). The MCT and AIT groups underwent 12 weeks of supervised exercise training. Exercise testing was performed as standard CPET treadmill test with analysis of VO2peak, the 6 MWT and a novel 30-minute submaximal treadmill test with capillary lactate AUC. Results All patients had statistically significant improvements in VO2peak, 6 MWT and lactate AUC after 12 weeks of exercise training: 6 MWT (p =0.035), VO2peak (p =0.049) and lactate AUC (p =0.002). Lactate AUC (p =0.046) and 6MWT (p =0.035), but not VO2peak revealed difference between the exercise modalities regarding functional work capacity. Conclusion 6-MWT and lactate AUC, but not VO2peak, were able to reveal a statistically significant improvement in functional capacity between different exercise modalities.

Automatic Liver Viability Scoring with Deep Learning and Hyperspectral Imaging.

Hyperspectral imaging (HSI) is a non-invasive imaging modality already applied to evaluate hepatic oxygenation and to discriminate different models of hepatic ischemia. Nevertheless, the ability of HSI to detect and predict the reperfusion damage intraoperatively was not yet assessed. Hypoxia caused by hepatic artery occlusion (HAO) in the liver brings about dreadful vascular complications known as ischemia-reperfusion injury (IRI). Here, we show the evaluation of liver viability in an HAO model with an artificial intelligence-based analysis of HSI. We have combined the potential of HSI to extract quantitative optical tissue properties with a deep learning-based model using convolutional neural networks. The artificial intelligence (AI) score of liver viability showed a significant correlation with capillary lactate from the liver surface (r = −0.78, p = 0.0320) and Suzuki’s score (r = −0.96, p = 0.0012). CD31 immunostaining confirmed the microvascular damage accordingly with the AI score. Our results ultimately show the potential of an HSI-AI-based analysis to predict liver viability, thereby prompting for intraoperative tool development to explore its application in a clinical setting.

Effects of Exercise Intensity on Pedal Force Asymmetry during Cycling

The purpose of the current investigation was to examine the effects of exercise intensity and a participant’s cycling experience on asymmetry in pedal forces during cycling. Participants were classified as cycling experienced (CE) or non-cycling experienced (NCE) based on self-reported training history. Participants completed an incremental cycling test via a cycle ergometer with inspired and expired gases, capillary blood lactate and pedaling forces collected throughout the test. Group X exercise intensity comparisons were analyzed at workloads corresponding to 2 mmol/L and 4 mmol/L for the blood lactate accumulation and peak power output, respectively. No Group X exercise intensity interactions for any variables (p &gt; 0.05) were observed. The main effect on the exercise intensity was observed for absolute (p = 0.000, η2 = 0.836) and relative (p = 0.000, η2 = 0.752) power outputs and pedal force effectiveness (PFE) (p = 0.000, η2 = 0.728). The main effect for the group was observed for absolute (p = 0.007, η2 = 0.326) and relative (p = 0.001, η2 = 0.433) power outputs, the absolute difference between the lower limbs in power production (p = 0.047, η2 = 0.191), the peak crank torque asymmetry index (p = 0.031, η2 = 0.222) and the PFE (p = 0.014, η2 = 0.280). The exercise intensity was observed to have no impact on asymmetry in pedaling forces during cycling.

Heart Rate and Muscle Oxygenation Kinetics During Dynamic Constant Load Intermittent Breath-Holds.

Introduction: Acute apnea evokes bradycardia and peripheral vasoconstriction in order to conserve oxygen, which is more pronounced with face immersion. This response is contrary to the tachycardia and increased blood flow to muscle tissue related to the higher oxygen consumption during exercise. The aim of this study was to investigate cardiovascular and metabolic responses of dynamic dry apnea (DRA) and face immersed apnea (FIA).Methods: Ten female volunteers (17.1 ± 0.6 years old) naive to breath-hold-related sports, performed a series of seven dynamic 30 s breath-holds while cycling at 25% of their peak power output. This was performed in two separate conditions in a randomized order: FIA (15°C) and DRA. Heart rate and muscle tissue oxygenation through near-infrared spectroscopy were continuously measured to determine oxygenated (m[O2Hb]) and deoxygenated hemoglobin concentration (m[HHb]) and tissue oxygenation index (mTOI). Capillary blood lactate was measured 1 min after the first, third, fifth, and seventh breath-hold.Results: Average duration of the seven breath-holds did not differ between conditions (25.3 s ± 1.4 s, p = 0.231). The apnea-induced bradycardia was stronger with FIA (from 134 ± 4 to 85 ± 3 bpm) than DRA (from 134 ± 4 to 100 ± 5 bpm, p < 0.001). mTOI decreased significantly from 69.9 ± 0.9% to 63.0 ± 1.3% (p < 0.001) which is reflected in a steady decrease in m[O2Hb] (p < 0.001) and concomitant increase in m[HHb] (p = 0.001). However, this was similar in both conditions (0.121 < p < 0.542). Lactate was lower after the first apnea with FIA compared to DRA (p = 0.038), while no differences were observed in the other breath-holds.Conclusion: Our data show strong decreases in heart rate and muscle tissue oxygenation during dynamic apneas. A stronger bradycardia was observed in FIA, while muscle oxygenation was not different, suggesting that FIA did not influence muscle oxygenation. An order of mechanisms was observed in which, after an initial tachycardia, heart rate starts to decrease after muscle tissue deoxygenation occurs, suggesting a role of peripheral vasoconstriction in the apnea-induced bradycardia. The apnea-induced increase in lactate was lower in FIA during the first apnea, probably caused by the stronger bradycardia.

Agreement between Arterial and Capillary pH, pCO2, and Lactate in Patients in the Emergency Department.

Background Blood gas analysis (BGA) is a frequent painful procedure in emergency departments. The primary objective of the study was a quantitative analysis to assess the mean difference and 95% confidence interval of the difference between capillary and arterial BGA for pH, pCO2, and lactate. Secondary objective was to measure the sensitivity and specificity of capillary samples to detect altered pH, hypercarbia, and lactic acidosis. Adults admitted to the ED were screened for inclusion. We studied the agreement between the two methods for pH, pCO2, and lactate with Bland-Altman bias plot analysis and receiver operating characteristic curves. Results One hundred ninety-seven paired analyses were included. Mean difference for pH between arterial and capillary BGA was 0.0095, and 95% limits of agreement (LOA) were −0.048 to 0.067. For pCO2, mean difference was −0.3 mmHg, and 95% LOA were −8.5 to 7.9 mmHg. Lactate mean difference was −0.93 mmol/L, and 95% LOA were −2.7 to 0.8 mmol/L. At a threshold of 7.34, capillary pH had 98% sensitivity and 97% specificity to detect acidemia; at 45.9 mmHg, capillary pCO2 had 89% sensitivity and 96% specificity to detect hypercarbia. At a threshold of 3.5 mmol/L, capillary lactate had 66% sensitivity to detect lactic acidosis. Conclusion Capillary BGA cannot replace arterial BGA despite high concordance between the two methods for pH and pCO2 and moderate concordance for lactate. Capillary measures had good accuracy when used as a screening tool to detect altered pH and hypercarbia but insufficient sensitivity and specificity when screening for lactic acidosis.

A survey of emergency and critical care veterinarians regarding IV fluid bolus therapy and monitoring practices in small animals.

To determine how veterinary emergency and critical care clinicians define IV fluid bolus therapy (FBT) and what constitutes a positive response to a fluid bolus. Online survey of 222 emergency and critical care veterinarians between December 17, 2018, and March 1, 2019. An online survey was provided to diplomates of the American College of Veterinary Emergency and Critical Care (ACVECC), residents of ACVECC-approved training programs, as well as house officers and emergency clinicians of a corporate multicenter emergency and specialty care veterinary hospital. The survey investigated the administration of various crystalloid, colloid, and blood products for FBT, as well as expected physiological responses. The majority of respondents considered balanced isotonic crystalloids appropriate for FBT (220/222 [99.1%]). Respondents showed greater variability in acceptance of 0.9% sodium chloride (105/222 [47.30%]), hypertonic (3-7%) sodium chloride (131/222 [59.01%]), and hydroxyethyl starch solutions (90/222 [40.54%]). Most respondents did not consider physiological plasma (44/222 [19.82%]) an appropriate choice. The most commonly used parameters for monitoring FBT responses were heart rate (220/222 [99.10%]), blood pressure (217/222 [97.75%]), capillary refill time (192/222 [86.49%]), lactate (181/222 [81.53%]), pulse pressure (151/222 [68.02%]), and rectal temperature (145/222 [65.32%]). The majority of respondents perceived that 0-20% (165/222 [74.32%]) of hypotensive patients are nonresponsive to FBT. Small animal emergency and critical care clinicians favored balanced isotonic electrolyte solutions and hypertonic sodium chloride solutions for FBT over other options. When monitoring responses to FBT, heart rate, blood pressure, capillary refill time, and plasma lactate were among the most commonly monitored parameters, and there was a lack of familiarity with others. Despite the widespread use of FBT, these findings outline the need for further prospective clinical trials regarding the ideal fluid type and rate, as well as the appropriate responses to FBT.

Muscle Recovery after a Single Bout of Functional Fitness Training.

Background: Functional fitness training (FFT) is a new exercise modality that targets functional multi-joint actions via both muscle-strengthening exercises and aerobic training intervals. The aim of the study was to examine muscle recovery over a 20 min period after an FFT workout in trained adults. Materials and methods: Participants were 28 healthy trained subjects. In a single session, a countermovement jump (CMJ) was performed to determine several mechanical variables (jump height, maximum velocity, power) before (preFFT) and 4, 10, and 20 min after the FFT workout (postFFT). In parallel, capillary blood lactate concentrations were measured pre- and 3 min postFFT. Heart rate was also measured before and after the workout, and perceived exertion was measured postFFT. Results: Significant differences between the time points preFFT and 4 min and 10 min postFFT, respectively, were produced in jump height (p = 0.022, p = 0.034), maximum velocity (p = 0.016, p = 0.005), average power relative (p = 0.018, p = 0.049), and average power total (p = 0.025, p = 0.049). No differences were observed in any of the variables recorded preFFT and 20 min postFFT. Conclusions: While mechanical variables indicating muscle fatigue were reduced 4 and 10 min postFFT, pre-exercise jump ability only really started to recover 20 min after FFT although not reaching pre-exercise levels. This means that ideally intervals of around 20 min of rest should be implemented between training bouts.