Blood Gas Parameters Research Articles

Risk prediction model for 24-hour mortality in preterm infants using lactate and blood gas analysis: A machine learning approach and retrospective cohort study

Background: This study aimed to evaluate the performance of machine learning algorithms using lactate and arterial blood gas parameters to predict the imminent risk of death in extremely low birth weight infants. Methods: A retrospective cohort study analyzing preterm infants with birth weight less than 1000 grams in a single-center tertiary neonatal intensive care unit in São Paulo, Brazil, between 2012 and 2017 was carried out. We included all infants with at least one arterial blood gas analysis with paired serum lactate. To assess 24-hour mortality risk, we conducted three machine learning algorithms (Logistic Regression, Extreme Gradient Boosting, and AutoML Tables). Results: We analyzed 1932 blood gas samples with matched lactate measurements. Our study population had a median gestational age of 27.1 (26 – 29.1) weeks and a median birth weight of 746 (600 – 880) grams. The Extreme Gradient Boosting model with lactate achieved the highest area under the receiver operating characteristic (AUROC) of 0.898. Base excess, lactate, and pH were, in order of importance, the most important features associated with 24-hour mortality. Conclusions: Incorporating lactate and blood gas samples into real-time mortality predictive models may aid to identify those preterm infants with a higher risk of death.

ASSESSMENT OF ARTERIAL BLOOD GAS COMPOSITION DEPENDING ON THE DEGREE OF MORBID OBESITY IN PATIENTS IN BARIATRIC SURGERY

Abstract. The work is devoted to the study of arterial blood gas parameters and comparison of capnographic determination of carbon dioxide at the end of exhalation (EtCO2) and the real pressure of carbon dioxide in arterial blood (paCO2) depending on the degree of morbid obesity in patients who were to undergo surgical bariatric interventions in 2012-2021. The study included 61 patients, whose age ranged from 22 to 69 years, body mass index from 40 to 91 kg/m2. The patients were divided into 3 groups depending on the degree of morbid obesity: group 1 - 20 patients with body mass index ≥ 40 (grade 3); group 2 - 25 patients with body mass index ≥ 50 (grade 4); group 3 - 16 patients with body mass index ≥ 60 (grade 5). Based on the data obtained, it was found that the state of the arterial blood gas composition indicates the presence of respiratory function disorders in patients with morbid obesity, which significantly reduce the compensatory capabilities of the body. Arterial hemoglobin saturation with oxygen (SaO2) tended to decrease, reaching a minimum in patients of the 1st group. The studied parameters of the arterial blood gas composition in patients of group 1 tended to worsen, and in patients of groups 2 and 3 they significantly worsened with an increase in the degree of morbid obesity. The maximum disruption of arterial blood gases was found in patients with a body mass index ≥ 60. The partial pressure of carbon dioxide at the end of exhalation (EtCO2) in patients with morbid obesity does not correspond to the partial pressure of carbon dioxide in arterial blood (paCO2).

Penetrating colon trauma - outcomes related to single versus multiple colonic injuries.

There is no conclusive evidence to guide surgical management in the presence of multiple colonic injuries as opposed to a single colonic injury, and whether multiple colonic suture lines are associated with worse outcomes than single suture lines. We reviewed the outcomes of penetrating colonic trauma in relation to whether patients had single versus multiple colonic suture lines (primary repair or anastomosis) following laparotomy. A retrospective study was conducted at a major trauma centre in South Africa from 2012-2020 for all patients over 18years who had sustained penetrating colon injury. 541 cases were included: 409 with single suture line and 54 with multiple suture lines. There were no differences between groups in terms of mechanism of injury (gunshot vs stab; p = 0.328), Injury Severity Score (p = 0.071), or Penetrating Abdominal Trauma Index (p = 0.396). Admission lactate was worse for multiple suture line patients (p = 0.049), but no other blood gas parameters were different, and there was no higher incidence of damage control surgery (p = 0.558) or ICU admission (p = 0.156) for this group. There was a higher rate of diversion in the multiple suture line group (p < 0.001). Univariable logistic regression did not show an increased risk of gastro-intestinal complications, suture line leak rate, or mortality for multiple suture lines compared to single. It appears that there is no appreciable difference in outcome between patients with a single colonic suture line compared to patients with more than one suture line following trauma laparotomy. In light of this, each injury should be treated on its own merit, in the context of the patient's overall physiological condition, without undue fear of leaving the patient with more than one colonic suture line. However, judicious use of diversion remains advisable.

Time to Try Something New: Establishing Rat Models of Lung Transplantation Under ECMO Support

<h3>Purpose</h3> Extracorporeal membrane oxygenation (ECMO) has emerged as an important preoperative, perioperative, and postoperative life-support requisite in lung transplantation. Therefore, we aimed to develop rat models of lung transplantation under veno-arterial (VA) and veno-venous (VV) ECMO support. <h3>Methods</h3> Adult male Sprague-Dawley rats weighing 400-450g (recipients, n=10; donors, n=10) were used. The ECMO circuits were initiated by venous drainage from the femoral vein with extracorporeal oxygen exchange and returned to the blood circulation through the right carotid artery (VA-ECMO) or external jugular vein (VV-ECMO). Before ECMO implantation, 5ml heparinized blood from the donor rat was drawn into tubes. Simultaneously, donor lungs were obtained after pulmonary arterial perfusion with low potassium dextran lung preservation solution. ECMO-supported orthotopic left lung transplantation was performed by using cuff technique. Arterial blood gases were measured at designated intervals throughout the experiments. <h3>Results</h3> We found that VA- and VV-ECMO provided sufficient oxygenation to support a smooth left single lung transplantation procedure. The intraoperative hemodynamic and blood gas parameters were maintained stable. <h3>Conclusion</h3> In this study, we first established rat models of lung transplantation under VA and VV ECMO support. This model provides an efficient, economical, and feasible platform for studying lung transplantation with ECMO. This model can be preclinically applied to unravel significant insights in support of further translational models in large animal and human lung transplantation.

Impact of Face Masks on Exercise Capacity and Lactate Thresholds in Healthy Young Adults.

Although many countries have introduced strict guidelines regarding mouth and nose coverage in public to contain infection rates during the SARS-CoV-2 pandemic, more information is needed regarding the impact of wearing face masks on lactate thresholds (LT) and performance parameters during exercise. Ten healthy male and 10 healthy female subjects (age = 33.4 [10.26]y, body mass index = 23.52 [2.36]kg/m2) performed 3 incremental performance tests, wearing no mask (NM), surgical mask (SM), and filtering face piece mask class 2 (FFP2), with a cycle ergometer. The authors analyzed changes in the LT, in blood gas parameters, and in the rating of perceived exertion (RPE). Performance at LT remained unchanged in subjects wearing SM or FFP2 in comparison with NM (162.5 [50.6] vs 167.2 [58.9] vs 162.2 [58.4]W with NM, SM, and FFP2, respectively, P = .24). However, the peak performance was significantly reduced wearing FFP2 compared with NM (213.8 [71.3] vs 230.5 [77.27]W, FFP2 vs NM, respectively, P < .001). Capillary pCO2 was increased while wearing SM as well as FFP2 compared with NM (29 [3.1] vs 33.3 [4] vs 35.8 [4.9]mmHg with NM, SM, and FFP2, respectively; P < .001), and pO2 decreased under maximum performance (84 [6.7] vs 79.1 [7.5] vs 77.3 [8.2]mmHg with NM, SM, and FFP2, P < .01). Importantly, rating of perceived exertion was significantly increased by wearing FFP2 compared with NM at LT according to Mader (16.7 [2.7] vs 15.3 [1.8] FFP2 vs NM, respectively, P < .01). Wearing face masks during exercise showed no effect on LT, limited maximum performance, and induced discrete changes in capillary pCO2 and pO2 within the physiologic range while increasing RPE at LT.

Multidimensional assessment and cluster analysis for OSA phenotyping.

Obstructive sleep apnea (OSA) is a heterogeneous disease with varying phenotype. A cluster analysis based on multidimensional disease characteristics, including symptoms, anthropometry, polysomnography, and craniofacial morphology, in combination with auto-continuous positive airway pressure titration response and comorbidity profiles, was conducted within a well-characterized cohort of patients with OSA, with the aim to refine the current phenotypic expressions of OSA with clinical implications. Two hundred ninety-one patients with a new diagnosis of moderate to severe OSA referred for auto-continuous positive airway pressure titration to the sleep center were included for analysis. In-laboratory polysomnography and craniofacial computed tomography scanning were performed, followed by an auto-continuous positive airway pressure titration. The symptom of excessive daytime sleepiness was assessed using the Epworth Sleepiness Scale. Three patient phenotypes-normal weight, nonsleepy, moderate OSA; obese, nonsleepy, severe OSA; and obese, sleepy, very severe OSA with craniofacial limitation-were identified. Among the polysomnography parameters, only percentage of N3 time of total sleep time (N3%) and mean pulse oxygen saturation were found to be associated with the Epworth Sleepiness Scale score, and they only explained a small fraction of the variation (R2 = .136). Neck circumference and craniofacial limitation were associated with the more severe phenotype, which had a higher prevalence of hypertension and metabolic syndrome, greater diurnal blood gas abnormalities, and worse positive airway pressure titration response. Three OSA phenotypes were identified according to multiple aspects of clinical features in patients with moderate to severe OSA, who differed in their prevalence of hypertension, metabolic syndrome, diurnal blood gas parameters, and continuous positive airway pressure titration response. Self-reported excessive daytime sleepiness was not related with the severity of sleep breathing disturbance, and craniofacial limitation was associated with the more severe phenotype. These findings highlight the necessity of integrating multiple disease characteristics into phenotyping to achieve a better understanding of the clinical features of OSA. Zhang XL, Zhang L, Li YM, etal. Multidimensional assessment and cluster analysis for OSA phenotyping. J Clin Sleep Med. 2022;18(7):1779-1788.

Lung and chest wall mechanical properties in metformin-treated and untreated models of type 2 diabetes

The adverse respiratory consequences of type 2 diabetes mellitus (T2DM) may reflect compromised lung function and/or alterations of the chest wall because of skeletal muscle stiffening. We assessed the separate contributions of these compartments to respiratory complications in diabetes and explored the effects of metformin on respiratory abnormalities. Experiments were performed in untreated rats (control, n = 7), high-fat diet-fed rats receiving streptozotocin (T2DM, n = 7), and metformin-treated diabetic rats (MET, n = 6). Newtonian resistance, tissue damping, and elastance were separately assessed for lung and chest wall components by measuring the esophageal pressure during forced oscillations at low (0 cmH2O), medium (3 cmH2O), and high positive end-expiratory pressure (PEEP) (6 cmH2O). Tissue hysteresivity was calculated as damping/elastance. Blood gas parameters were used to assess gas exchange, and lung histology was performed to characterize collagen expression. T2DM at low PEEP compromised airway and lung tissue mechanics in association with gas-exchange defects and collagen overexpression. Abnormal chest wall mechanics in T2DM was indicated only by decreased tissue hysteresivity. No difference in lung or chest wall mechanics, gas exchange, or lung histology was observed between the MET and control groups. These findings suggest the primary involvement of the pulmonary system in the respiratory consequences of T2DM, with chest wall properties only disturbed by a shift toward the dominance of elastic forces at low PEEP. The adequacy of metformin to treat the adverse respiratory consequences of diabetes was also revealed, in addition to its well-established beneficial effects on other organs.NEW & NOTEWORTHY The present study examined the contributions of the lungs and chest wall to respiratory complications in a rat model of diabetes and clarified the effects of metformin on these changes. At low positive end-expiratory pressure, type 2 diabetes was linked to dysfunctional airway and lung tissue mechanics in relation with gas-exchange defects and collagen overexpression, whereas decreased tissue hysteresivity was manifested in the chest wall abnormalities. Metformin treated all adverse respiratory consequences of diabetes.

How Important Are Arterial Blood Gas Parameters for Severe Head Trauma in Children?

Aim: Our aim in this study is to consider the relationship between arterial blood gas (ABG) parameters and prognosis in severe head trauma in children.&#x0D; Material and Methods: Patients younger than 17 years of age with a Glasgow Coma Scale (GCS) of 8 and below with a history of head trauma were retrospectively analyzed. The relation of ABG parameters taken at the time of admission with mortality was examined. Independent sample T-test was used for pH, PCO2 and base extract (BE) parameters in ABG, and Mann Whitney U test was used for PO2 and lactate parameters.&#x0D; Results: 48 patients were included in the study. Gender, age, admission blood pressure arterial values, GCS and Abbreviated Injury Scale (AIS) scores, length of stay in intensive care, and the surgical application did not differ statistically between the patient groups who died and survived (p&gt; 0.05). Ph and PO2 values were lower, PCO2, lactate and BE values were found to be higher in the deceased patient group compared to the living patient group (p˂0.05). The presence of acidosis, hypercapnia, or hyperlactatemia according to ABG values in the patient group who died was statistically significantly higher (p˂0.05).&#x0D; Conclusion: In our study, we found that the presence of acidosis, hypercapnia, and hyperlactatemia in patients according to ABG values increased mortality. In addition, according to the results of ROC analysis, we found that high PCO2 and lactate values could be specific indicators indicating poor prognosis. We think that PCO2 and lactate measured in arterial blood may be biomarkers that can determine the prognosis.

A comparison of continuous blood gas monitors during cardiopulmonary bypass LivaNova B-Capta, Terumo CDI 500, spectrum medical M4.

Accurate and precise management of blood gas parameters during cardiopulmonary bypass (CPB) is crucial to patient care and outcome. This study compares the data provided by Livanova B-Capta, Terumo CDI500, and Spectrum Medical M4 with the results from a gold standard blood gas analyzer to test accuracy. All three continuous blood gas monitoring (CBGM) devices were used simultaneously during CPB on one dedicated HLM. Arterial and venous blood samples of 40 adult patients who underwent elective cardiac surgery with CPB were taken from the CPB circuit. Pre- and post-alignment deviation in percentages are compared with CLIA guidelines. B-Capta data reveals that the deviation pre-alignment is small and within the CLIA threshold for all parameters. Pre-alignment data for CDI 500 is within CLIA threshold for SvO2 and PaO2. The pre-alignment data for the M4 exceeds the CLIA thresholds for all parameters. Post-alignment data for B-Capta and CDI 500 reveals an accurate agreement for Hb and Hct and strong agreement for PaO2. All values for B-Capta and CDI 500 are within CLIA threshold values except for SvO2. Post-alignment the M4 exceeded the CLIA threshold value only for PaO2. B-Capta is the only CBGM device that operates within the CLIA guidelines and is in agreement with laboratory values prior to alignment.

Identification of data elements for blood gas analysis dataset: a base for developing registries and artificial intelligence-based systems

BackgroundOne of the challenging decision-making tasks in healthcare centers is the interpretation of blood gas tests. One of the most effective assisting approaches for the interpretation of blood gas analysis (BGA) can be artificial intelligence (AI)-based decision support systems. A primary step to develop intelligent systems is to determine information requirements and automated data input for the secondary analyses. Datasets can help the automated data input from dispersed information systems. Therefore, the current study aimed to identify the data elements required for supporting BGA as a dataset.Materials and methodsThis cross-sectional descriptive study was conducted in Nemazee Hospital, Shiraz, Iran. A combination of literature review, experts’ consensus, and the Delphi technique was used to develop the dataset. A review of the literature was performed on electronic databases to find the dataset for BGA. An expert panel was formed to discuss on, add, or remove the data elements extracted through searching the literature. Delphi technique was used to reach consensus and validate the draft dataset.ResultsThe data elements of the BGA dataset were categorized into ten categories, namely personal information, admission details, present illnesses, past medical history, social status, physical examination, paraclinical investigation, blood gas parameter, sequential organ failure assessment (SOFA) score, and sampling technique errors. Overall, 313 data elements, including 172 mandatory and 141 optional data elements were confirmed by the experts for being included in the dataset.ConclusionsWe proposed a dataset as a base for registries and AI-based systems to assist BGA. It helps the storage of accurate and comprehensive data, as well as integrating them with other information systems. As a result, high-quality care is provided and clinical decision-making is improved.

Comparison between pulse oximetry and venous blood gas analyses to assess lamb asphyxia at parturition

Early detection of fetal distress at lambing is essential to reduce mortality. Practicality and accuracy of pulse oximetry to assess oxygenation status in newborn lambs under field conditions was evaluated. Oximetry was compared with blood gas analyses and included assessment of vitality (Apgar test) and vigour (attempt to and successful standing and suckling) of 135 Finnish by Polwarth lambs. Sampling of data was obtained immediately after fetal expulsion; percentage of oxygen saturation (satO2) was measured using a pulse oximeter clamped to an ear, and was compared with gas analyses variables measured from a jugular vein sample (Gas Analyser: Siemens-Rapidlab 248®). Correlations between satO2 measured by pulse oximetry and venous blood gas parameters either directly (partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2) and pH) or estimated (bicarbonate concentration, extracellular fluid base excess, and oxygen saturation) were studied. Considering pH as a good indicator of hypoxia at parturition, data was grouped as: G1 = pH < 7.1; G2 = 7.1 ≤ pH < 7.2; G3 = 7.2 ≤ pH < 7.3 and G4 = pH ≥ 7.3. Saturation of oxygen measured by pulse oximetry correlated significantly with pCO2 (r = −0.50; P < 0.001), pH (r = 0.36; P < 0.001) and pO2 (r = 0.2, P = 0.04) measured by blood gas analyses. Lambs with low pH values (G1 = pH ≤ 7.1, acidosis) showed the lowest percentage to attempt and success to stand and suck, lowest Apgar score (G1 = 6.7, G2 = 8.6, G3 = 8.6, G4 = 8.5, P = 0.025), lowest percentage of satO2 measured by oximetry (G1 = 78.8%, G2 = 87.5%, G3 = 87.7%, G4 = 92.1%, P = 0.011) and highest pCO2 (G1 = 78.5, G2 = 73.8, G3 = 65.8, G4 = 53.8 mmHg, P < 0.001). Pulse oximetry appears an accurate method to evaluate lamb birth asphyxia, helping to identify oxygenation constraints during labour, facilitating priority of perinatal handling, and thus improving lamb survival.

Modified Bain's Circuit as an Alternate to Non-invasive Ventilation in COVID 19.

IntroductionCOVID-19 is a pandemic that severely affects the lungs. Symptomatically affected individuals often become severely hypoxic, requiring non-invasive ventilation. The scarcity of resources in resource-compromised countries like India led to the adoption of novel strategies like using Bain’s circuit for assisting spontaneous ventilation. This study compares the outcome when a standard circuit is replaced with a shortened Bain’s circuit.Aims and objectivesTo compare shortened Bain’s circuit and bilevel positive airway pressure (BiPAP) in spontaneously ventilated COVID 19 patients with regards to effects on hemodynamic stability and efficacy of ventilation using blood gas analysis.MethodologyTwenty-four COVID patients aged between 35-70 years, requiring non-invasive ventilation but not tolerating BiPAP or not improving on BiPAP were enrolled in the study. Baseline heart rate and arterial blood gases (ABG) were recorded. Patients were then ventilated using shortened Bain’s circuit. Heart rate and ABG were then recorded two hours after ventilation.ResultsHemodynamic and blood gas parameters were comparable between the two groups at baseline and on BiPAP. Group A showed better hemodynamic and blood gas profiles compared to group B, but the difference was not statistically significant because of small sample size.ConclusionShortened Bain’s circuit may be a viable alternative to non-invasive ventilation in spontaneously breathing hypoxic patients with efficacy comparable to a standard Bain’s circuit and reduced chances of carbon dioxide retention. Studies with a larger sample size are needed to further validate the conclusion.

Arterial Blood Gas and Rotational Thromboelastometry Parameters in Healthy Rescuers Incidentally Exposed to Nitroglycerin, Nitrogen Compounds, and Combustion Products.

Acute exposure to nitrogen compounds combined with a massive inhalation of air pollutants can influence respiratory and cardiovascular symptoms and coagulation abnormalities in accidentally exposed healthy adults during cave detonation operations. Italian alpine and cave rescuers widened a cave in the Abisso Luca Kralj in Trieste, Italy. Volunteers inside the cave were accidentally exposed to the fumes from an uncontrolled detonation of blasting gelatin microcharges. We performed a retrospective cohort study on the clinical data, arterial blood gas analysis, and rotational thromboelastometry parameters from the rescuers involved in the accident. Ninety-three healthy rescuers were involved in the uncontrolled detonation: 47 volunteers handled a mixture of nitrogen compounds (blaster group), and 46 volunteers did not (nonblaster group). After the accident, statistically significant differences (P<0.05) in arterial blood gas values were observed between the groups, with a pattern of mild respiratory acidosis with hypercapnia in the nonblaster group and severe mixed acid-base disorder with hypoxia and hypercapnia in the blaster group. Mild hyperfibrinolysis was observed in 44 volunteers in the blaster group, as were associated bleeding symptoms in 34 volunteers; no significant coagulation modifications were recorded in the nonblaster group. Respiratory acidosis with hypoxia, hypercapnia, a compensatory metabolic response, and mild hyperfibrinolysis were probably related to the combined effect of nitrogen compounds and the inhaled toxic products of detonation. Therefore, each element exerts a determinant effect on promoting the biological toxicity of the others.

Effect of later cord clamping on umbilical cord blood gas in term neonates of diabetic mothers: a randomized clinical trial

ObjectiveTo evaluate the effect of later cord clamping (LCC) on umbilical arterial blood gas in neonates of diabetic mothers.MethodsThis prospective study included a group of 160 diabetic mothers (DM) whose neonates were randomized to immediate cord clamping (ICC) (≤ 15 s after birth) or LCC (≥ 30 s after birth), and a group of 208 non-diabetic mothers (NDM) whose neonates were randomized to ICC or LCC as a reference. Cord arterial pH, base excess (BE), bicarbonate (HCO3−), partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), lactate, hemoglobin, hematocrit and glucose were compared among groups.ResultsIn neonates of DM, there was no significant difference in cord arterial pH between the ICC and LCC group. LCC of ≥ 30 s decreased umbilical arterial HCO3− and BE and increased lactate (ICC versus LCC, HCO3−: 24.3 (22.7, 25.8) versus 23.7 (22.3, 24.7) mmol/L, P = 0.01; BE: -2.70 (-4.80, -1.50) versus − 3.72 (-5.66, -2.36) mmol/L, P = 0.006; lactate: 2.1 (1.6, 3.7) versus 2.7 (2.1, 4.3) mmol/L, P = 0.005), without the alterations of pCO2, pO2, hemoglobin, hematocrit and glucose. Similar results were found in neonates of NDM (ICC versus LCC, HCO3−: 24.3 (23.1, 25.7) versus 23.5 (22.3, 24.8) mmol/L, P = 0.01; BE: -2.39 (-3.73, -1.51) versus − 3.40 (-4.73, -1.91) mmol/L, P = 0.001; lactate: 2.2 (1.9, 3.3) versus 2.5 (2.0, 4.3) mmol/L, P = 0.01), except for the higher level of hemoglobin in the LCC group. The majority of diabetic mothers (ICC: 92.0%; LCC: 91.8%) had good blood glucose control. No differences were observed in acid-base status and glucose between neonates of DM and neonates of NDM in both ICC and LCC, but hemoglobin and hematocrit were elevated after ICC in neonates of DM compared to neonates of NDM.ConclusionsLater cord clamping of ≥ 30 s resulted in a tendency towards metabolic acidosis of umbilical arterial blood in neonates of DM and NDM. Umbilical arterial blood gas parameters at birth were similar in neonates of DM and NDM.Trial registrationClinicalTrials.gov: NCT04369313; date of registration: 30/04/2020 (retrospectively registered).

The activation of SIRT3 by dexmedetomidine mitigates limb ischemia-reperfusion-induced lung injury.

BackgroundThe lung is one of the most sensitive organs, and is vulnerable to injury caused by limb ischemia-reperfusion (LIR). Dexmedetomidine, an anesthetic adjunct, has been shown to have therapeutic effects on lung injury secondary to LIR. This study aimed to investigate the role of dexmedetomidine in ameliorating LIR-induced lung injury in a mouse model of bilateral hind LIR.MethodsIn this study, 75 mice were randomly divided into 5 groups to prepare the LIR model. After the model was established, arterial blood was extracted for blood gas analysis. The pathological changes of lung tissue, lung wet/dry weight ratio, arterial blood gas analysis, detection of myeloperoxidase (MPO) activity, the content of reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in oxidative stress indexes, mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) content and cytochrome c content were measured, and the relative protein expression levels of sirtuin-3 (SIRT3) and apoptosis factor Bcl-2 related X protein (Bax), B-cell Lymphoma 2 (Bcl-2), cleaved caspase 3, and nuclear factor erythroid 2-related factor 2 (Nrf2) and cytoplasmic heme oxygenase-1 (HO-1).ResultsPretreatment with dexmedetomidine dramatically ameliorated LIR-induced lung injury, the wet/dry weight ratio, the arterial blood gas parameters, and enhanced SIRT3 expression. Moreover, dexmedetomidine significantly inhibits ROS and MDA level and restores antioxidant enzyme activities (SOD, GSH-Px). Of note, dexmedetomidine suppressed LIR-induced lung tissue apoptosis by modulating apoptosis-associated protein such as Bax, Bcl-2, and cleaved caspase 3. Moreover, dexmedetomidine inhibited the LIR-induced decreases in MMP, ATP levels, and the release of cytochrome c of LIR to maintain mitochondrial function. Latest study has shown that activating Nrf2 could promote SIRT3 expression to alleviate IR injury. Intriguingly, dexmedetomidine could facilitate nuclear Nrf2 and cytoplasmic HO-1 expression.ConclusionsOur findings suggest that dexmedetomidine protects against LIR-induced lung injury by inhibiting the oxidative response, mitochondrial dysfunction and apoptosis. The mechanism appears to be at least partly mediated through the upregulation of SIRT3 expression.

Hemoglobin-albumin clusters as an artificial O2 carrier: Physicochemical properties and resuscitation from hemorrhagic shock in rats.

A bovine hemoglobin (HbBv) or human adult hemoglobin (HbA) wrapped covalently by human serum albumins (HSAs), hemoglobin-albumin clusters (HbBv-HSA3 and HbA-HSA3 ), are artificial O2 carriers used as a red blood cell substitute. This article describes the physicochemical properties of the HbBv-HSA3 and HbA-HSA3 solutions, and their abilities to restore the systemic condition after resuscitation from hemorrhagic shock in anesthetized rats. The HbBv-HSA3 and HbA-HSA3 , which have high colloid osmotic activity, showed equivalent solution characteristics and O2 binding parameters. Shock was induced by 50% blood withdrawal. Rats exhibited hypotension and significant metabolic acidosis. After 15 min, the rats were administered shed autologous blood (SAB), HbBv-HSA3 , HbA-HSA3 , or Ringer's lactate (RL) solution. Survival rates, circulation parameters, hematological parameters, and blood gas parameters were monitored during the hemorrhagic shock and for 6h after administration. All rats in the SAB, HbBv-HSA3 , and HbA-HSA3 groups survived for 6h. The HbBv-HSA3 and HbA-HSA3 groups restored mean arterial pressure after the resuscitation. No remarkable difference was observed in the time courses of blood gas parameters in any resuscitated group except for the RL group. Serum biochemical tests showed increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HbBv-HSA3 and HbA-HSA3 groups compared to the SAB group. Therefore, we observed other rats awakened after resuscitation with HbA-HSA3 for 7 days. The blood cell count, AST, and ALT recovered to the baseline values by 7 days. All the results implied that HbBv-HSA3 and HbA-HSA3 clusters provide restoration from hemorrhagic shock as an alternative material for SAB transfusion.

Effect of post-operative goal-directed fluid therapy (GDFT) on organ function after orthotopic liver transplantation: Secondary outcome analysis of the COLT randomised control trial

BackgroundGoal-directed fluid therapy (GDFT) has been shown to reduce the complications following a variety of major surgical procedures, possibly mediated by improved organ perfusion and function. We have shown that it is feasible to randomise patients to GDFT or standard fluid management following liver transplant in the cardiac-output optimisation following liver transplantation (COLT) trial. The current study compares end organ function in patients from the COLT trial who received GDFT in comparison to those receiving standard care (SC) following liver transplant. MethodsAdult patients with liver cirrhosis undergoing liver transplantation were randomised to GDFT or SC for the first 12 h following surgery as detailed in a published trial protocol. GDFT protocol was based on stroke volume (SV) optimisation using 250 ml crystalloid boluses. Total fluid administration and time to extubation were recorded. Hourly SV and cardiac output (CO) readings were recorded from the non-invasive cardiac output monitoring (NICOM) device in both groups. Pulmonary function was assessed by arterial blood gas (ABG) and ventilatory parameters. Lung injury was assessed using PaO2:FiO2 ratios and calculated pulmonary compliance. The KDIGO score was used for determining acute kidney injury. Renal and liver graft function were assessed during the post-operative period and at 3 months and 1-year. Results60 patients were randomised to GDFT (n = 30) or SC (n = 30). All patients completed the 12 h intervention period. GDFT group received a significantly higher total volume of fluid during the 12 h trial intervention period (GDFT 5317 (2335) vs. SC 3807 (1345) ml, p = 0.003); in particular crystalloids (GDFT 3968 (2073) vs. SC 2510 (1027) ml, p = 0.002). There was no evidence of significant difference between the groups in SV or CO during the assessment periods. Time to extubation, PaO2: FIO2 ratios, pulmonary compliance, ventilatory or blood gas measurements were similar in both groups. There was a significant rise in serum creatinine from baseline (77 μmol/L) compared to first (87 μmol/L, p = 0.039) and second (107 μmol/L, p = 0.001) post-operative days. There was no difference between GDFT and SC in the highest KDIGO scores for the first 7 days post-LT. At 1-year follow-up, there was no difference in need for renal replacement therapy or graft function. ConclusionsIn this randomised trial of fluid therapy post liver transplant, GDFT was associated with an increased volume of crystalloids administered but did not alter early post-operative pulmonary or renal function when compared with standard care.

Relationship between seizures and metabolic acidosis: a prospective observational study

Objective: To assess changes in blood gas parameters, such as pH, partial carbon dioxide pressure (PaCO2), bicarbonate (HCO3), base deficit, and lactate values, in patients who present to the emergency care unit after a seizure. Methods: This is a prospective study on patients who suffered a generalized tonic-clonic seizure. The demographic and biochemical data of the patients and their blood gas parameters were recorded both at the time of presentation to the emergency department and during the follow-up examination. Results: A total of 68 patients were included in the study. Among the patients, 60.3% (41) were male. The median age of the patients was 43 years (IQR: 29-65.25). The median initial lactate value was 5.7 mmol/L (25th and 75th percentiles: 3.5–8.5 mmol/L). The median follow-up lactate value was 1.8 mmol/L (25th and 75th percentiles: 1.1–2.8 mmol/L). The statistical analysis of the blood gas parameters revealed a statistically significant difference in the pH, PaCO2, base deficit, and lactate values between the initial and follow-up evaluations (P&lt;0.001). Conclusion: The results of our study suggest that metabolic acidosis with high anion gap may develop due to the increase in the lactate levels as a result of a tonic-clonic seizure.

Accounting for arterial and capillary blood gases for calculation of cerebral blood flow in preterm infants

One of the most feared neurological complications of premature birth is intraventricular hemorrhage, frequently triggered by fluctuations in cerebral blood flow (CBF). Although several techniques for CBF measurement have been developed, they are not part of clinical routine in neonatal intensive care. A promising tool for monitoring of CBF is its numerical assessment using standard clinical parameters such as mean arterial pressure, carbon dioxide partial pressure (pCO2) and oxygen partial pressure (pO2). A standard blood gas analysis is performed on arterial blood. In neonates, capillary blood is widely used for analysis of blood gas parameters. The purpose of this study was the assessment of differences between arterial and capillary analysis of blood gases and adjustment of the mathematical model for CBF calculation to capillary values. The statistical analysis of pCO2 and pO2 values collected from 254 preterm infants with a gestational age of 23–30 weeks revealed no significant differences between arterial and capillary pCO2 and significantly lower values for capillary pO2. The estimated mean differences between arterial and capillary pO2 of 15.15 mmHg (2.02 kPa) resulted in a significantly higher CBF calculated for capillary pO2 compared to CBF calculated for arterial pO2. Two methods for correction of capillary pO2 were proposed and compared, one based on the mean difference and another one based on a regression model.Conclusion: Capillary blood gas analysis with correction for pO2 as proposed in the present work is an acceptable alternative to arterial sampling for the assessment of CBF.What is Known:• Arterial blood analysis is the gold standard in clinical practice. However, capillary blood is widely used for estimating blood gas parameters.• There is no significant difference between the arterial and capillary pCO2values, but the capillary pO2differs significantly from the arterial one.What is New:• The lower capillary pO2values yield significantly higher values of calculated CBF compared to CBF computed from arterial pO2measurements.• Two correction methods for the adjustment of capillary pO2 to arterial pO2that made the difference in the calculated CBF insignificant have been proposed.

Hemolysis and blood gas analysis: it’s time for a change!

Modern blood gas analyzers are not able to identify hemolysis, lipemia and icterus; therefore, the aim of this study was to assess the influence of hemolysis on blood gas samples. Blood gas analysis represents an essential part in the diagnosis and treatment of critically ill patients, including those affected by the pandemic coronavirus disease 2019 (COVID-19). Hemolysis, lipemia, and icterus, are causes of clinical misinterpretation of laboratory tests. A total of 1244 blood gas specimens were collected over a one-week period from different clinical wards, including the Emergency Department, and were assessed for serum indices on Cobas C6000 CE (Roche Diagnostics, Mannheim, Germany). The prevalence of hemolysis, lipemia, and icterus were 5%, 12%, and 14%, respectively. Sample storage at room temperature, delivery to central laboratory using pneumatic tube system, as well as small sample size, strongly affected blood gas parameters (p < .01). Hemolysis led to an increase in analytical bias for pH, pO2, and potassium, and a significant decrease for pCO2, HCO3 −, sodium, and Ca2+ (p <.01). Currently, hemolysis detection systems are not yet widespread, and a rapid centrifugation of samples after blood gas analysis along with the assessment of serum indices represent the only prompt approach to identify unsuitable results, avoiding pitfalls in clinical decision-making, although it cannot be applied to the Emergency Department routine. Blood gas analyzers manufacturers and suppliers should implement automated built-in serum indices detection systems.