Blood Gas Profile Research Articles

Cardiovascular responses to heat and cold exposure are altered by preterm birth in guinea pigs.

Adversity early in life can modify the trajectory for disease risk extending decades beyond the event. Preterm birth produces persistent cardiovascular alterations that may appear maladaptive in adulthood. We have previously hypothesized that those born preterm may exhibit cardiovascular vulnerability in the climate change context. Further, this vulnerability may be present as early as childhood. We aimed to identify the early signs of cardiovascular dysfunction at childhood-equivalent age using our animal model of preterm birth. Using a whole-body thermal stress test, guinea pigs aged 35-d and 38-d (equivalent to 8-10-year-old children) and born at term or preterm gestations were exposed to progressive hyper- (TC = 41.5°C) and hypo-thermia (TC = 34°C; normothermia TC = 39°C). Comprehensive cardiovascular monitoring included ECG, blood pressure, microvascular perfusion, blood gas, and catecholamine profile, as well as skin and core body temperature. Preterm-born animals exhibited attenuated vascular responses to hyperthermic stress, and a significant elevation in systolic blood pressure in response to hypothermic stress. Such responses are similar to those observed in elderly populations and indicate the presence of cardiovascular dysfunction. This is the first study to demonstrate the impact of preterm birth on the cardiovascular response to both heat and cold stress. Further, this dysfunction has been observed at an earlier age than that achievable using traditional stress testing techniques. The present findings warrant further investigation.

Effects of a blend of acidifiers added continuously to the drinking water of nursery piglets

Context Adding organic and inorganic acids to the drinking water is a potential alternative to improve production results in nursery piglets, and a strategy for reducing the use of antimicrobials. Aims To assess the effects of adding a blend of organic and inorganic acids to drinking water on the oxireduction potential (ORP) of water, and growth performance, biochemical, antioxidant and blood gas profiles, intestinal morphometry, biometry of organs, and intestinal microbiome of nursery piglets. Methods Experiment involved 1080 female piglets assessed over 30 days (Landrace × Large White, weaned at 26 days of age, weighing 6.8 ± 0.29 kg), randomly assigned to the following three treatments: (1) piglets received drinking water of natural pH of 7.39 (pH7.39), (2) piglets received drinking water of pH of 5.31 (pH5.31), and (3) piglets received drinking water of pH of 3.40 (pH3.40), with eight replicates and 45 piglets/stall. Piglets had ad libitum access to diet and water throughout the experiment, and received different diets in each phase. Key results Receiving drinking water of pH3.40 promoted a higher ORP, and a lower total water consumption was observed in Starter II piglets with pH5.31. There was no treatment effect on the performance, but mortality was lower in starter piglets in the pH3.40 treatment. Animals in the pH3.40 treatment had lower blood alanine aminotransferase and aspartate aminotransferase activities, differing from the result obtained for total cholesterol concentrations. Animals in the pH3.40 treatment showed a lower concentration of total protein than did piglets in the pH7.39 treatment. Piglets in the pH3.40 treatment had higher weights of empty stomach, spleen, and liver with gallbladder than did those in the pH7.39 treatment. Animals in the pH3.40 treatment showed a lower relative abundance of the Escherichia–Shigella genus and bacteria of Enterobacteriaceae family than did those in the pH5.31 treatment. Conclusions Acidification of drinking water to pH3.40 for nursery piglets can be used to partially increase the ORP of the water, and promote a greater weight of organs with metabolic and immune functions, while decreasing mortality. In addition, acidification of drinking water does not compromise performance or intestinal histology, but improves the profile of the intestinal microbiome in piglets. Implications This research has provided new information on the effects of acidifiers in the drinking water for nursery piglets and has shown their potential use for bolstering general health.

Anesthesia for lung transplantation in children under 12 years of age: a single center experience of China

PurposeThis study aims to provide a comprehensive overview of anesthesia management strategies employed in pediatric lung transplantation.MethodsA retrospective analysis was conducted on data from 14 pediatric patients who underwent lung transplantation at the Wuxi Center between September 2019 and November 2022. Patient demographics, surgical particulars, airway management, utilization of extracorporeal support, fluid administration, blood gas and electrolyte profiles, and postoperative outcomes were systematically documented and subsequently summarized.ResultsOf the 14 patients, 7 received extracorporeal membrane oxygenation (ECMO) and 1 received cardiopulmonary bypass (CPB). The average operation time was 303 ± 53 min, with the median extubation time of 26 h. The entirety of pediatric lung transplant procedures was executed successfully, resulting in the discharge of thirteen patients postoperatively. Regrettably, one patient died due to infectious shock on the fourth postoperative day.ConclusionThe achievement of successful pediatric lung transplantation necessitates effective perioperative anesthesia management, with a focal emphasis on circulatory control. Real-time measurements serve as the cornerstone for decision-making. Proactive administration of vasoactive agents is integral to sustaining hemodynamic stability. The judicious assessment of ECMO necessity is paramount, favoring central ECMO during the surgical intervention.

Ambulatory 7-day mechanical circulatory support in sheep model of pulmonary hypertension and right heart failure

Right heart failure is the major cause of death in pulmonary hypertension. Lung transplantation is the only long-term treatment option for patients who fail medical therapy. Due to the scarcity of donor lungs, there is a critical need to develop durable mechanical support for the failing right heart. A major design goal for durable support is to reduce the size and complexity of devices to facilitate ambulation. Toward this end, we sought to deploy wearable mechanical support technology in a sheep disease model of chronic right heart failure. In 6 sheep with chronic right heart failure, a mechanical support system consisting of an extracorporeal blood pump coupled with a gas exchange unit was attached in a right atrium-to-left atrium configuration for up to 7days. Circuit performance, hematologic parameters, and animal hemodynamics were analyzed. Six subjects underwent the chronic disease model for 56 to 71days. Three of the subjects survived to the 7-day end-point for circulatory support. The circuit provided 2.8 (0.5) liter/min of flow compared to the native pulmonary blood flow of 3.5 (1.1) liter/min. The animals maintained physiologically balanced blood gas profile with a sweep flow of 1.2 (1.0) liter/min. Two animals freely ambulated while wearing the circuit. Our novel mechanical support system provided physiologic support for a large animal model of pulmonary hypertension with right heart failure. The small footprint of the circuit and the low sweep requirement demonstrate the feasibility of this technology to enable mobile ambulatory applications.

Physiological effects of N95 respirators on rescuers during cardiopulmonary resuscitation

ObjectivesThere is a lack of evidence in the medical literature reporting the physiological stress imposed by the wearing of N95 respirators during cardiopulmonary resuscitation (CPR) in healthcare providers. The aim of this study is to monitor the changes in hemodynamics and blood gas profiles in rescuers during the performance of CPR while wearing N95 respirators. MethodsThirty-two healthy healthcare workers performed standard CPR on manikins, each participant conducted 2 min of chest compression followed by 2 min of rest for 3 cycles. A non-invasive blood gas measuring device via a fingertip detector was used to collect arterial blood gas and hemodynamic data. Student t-test was used for comparison of various physiologic parameters before and after each session of chest compression. ResultsThere were no significant differences in arterial blood gas profiles including partial pressure of arterial carbon dioxide and partial pressure of arterial oxygen before and after each session of chest compression (p > 0.05 for all). Heart rate and cardiac output were significantly higher after CPR (p < 0.05 for all), but no significant changes were found on blood pressure. ConclusionsOur data suggest that healthcare providers wearing N95 respirators during provision of CPR in a short period of time does not cause any significant abnormalities in blood gas profiles and blood pressure. This may provide evidence to reassure the safe use of N95 respirator during performance of CPR.

Using time-course as an essential factor to accurately predict sepsis-associated mortality among patients with suspected sepsis

BackgroundBiomarker dynamics in different time-courses might be the primary reason why a static measurement of a single biomarker cannot accurately predict sepsis outcomes. Therefore, we conducted this prospective hospital-based cohort study to simultaneously evaluate the performance of several conventional and novel biomarkers of sepsis in predicting sepsis-associated mortality on different days of illness among patients with suspected sepsis. MethodsWe evaluated the performance of 15 novel biomarkers including angiopoietin-2, pentraxin 3, sTREM-1, ICAM-1, VCAM-1, sCD14 and 163, E-selectin, P-selectin, TNF-alpha, interferon-gamma, CD64, IL-6, 8, and 10, along with few conventional markers for predicting sepsis-associated mortality. Patients were grouped into quartiles according to the number of days since symptom onset. Receiver operating characteristic curve (ROC) analysis was used to evaluate the biomarker performance. ResultsFrom 2014 to 2017, 1483 patients were enrolled, of which 78% fulfilled the systemic inflammatory response syndrome criteria, 62% fulfilled the sepsis-3 criteria, 32% had septic shock, and 3.3% developed sepsis-associated mortality. IL-6, pentraxin 3, sCD163, and the blood gas profile demonstrated better performance in the early days of illness, both before and after adjusting for potential confounders (adjusted area under ROC curve [AUROC]:0.81–0.88). Notably, the Sequential Organ Failure Assessment (SOFA) score was relatively consistent throughout the course of illness (adjusted AUROC:0.70–0.91). ConclusionIL-6, pentraxin 3, sCD163, and the blood gas profile showed excellent predictive accuracy in the early days of illness. The SOFA score was consistently predictive of sepsis-associated mortality throughout the course of illness, with an acceptable performance.

Blood Gas, Acid-Base and Electrolyte Analysis in Healthy Dromedary Camel Calves up to 21 Days of Life.

The importance of prompt evaluation and care of the newborn is essential for reducing neonatal mortality, which represents a major cause of loss in camelids. This study investigated the blood gases, acid-base and electrolyte profiles in healthy dromedary calves during the first 3 weeks of life, assessing possible associations with age. Twenty-one dromedary camel calves aged 1 to 21 days were sampled, and venous whole blood analyzed through a VETSTAT® analyzer. The following parameters were measured: sodium (Na+), potassium (K+), chloride (Cl-), hydrogen ion concentration (pH), partial pressure carbon dioxide (pCO2), partial pressure oxygen (pO2), total hemoglobin concentration (tHb), hemoglobin oxygen saturation (sO2), total carbon dioxide (tCO2), bicarbonate (HCO3-), base excess (BE) and anion gap (AG). Calves were divided in two groups; younger calves (1-10 d), and older calves (11-21 d). Statistical analysis showed an effect of age, with lower K+ (p < 0.001) and higher Na+ and Cl- (p < 0.05) mean concentrations in the younger calves compared to the older ones, and higher pCO2 and lower sO2 mean concentrations in the older group. These preliminary results firstly described the blood gas, acid-base and electrolyte profiles in the healthy dromedary calf during the first 3 weeks of age, suggesting an effect of age on some parameters.

Multiple-Vessel-Based Blood Gas Profiles Analysis Revealed the Potential of Blood Oxygen in Mammary Vein as Indicator of Mammary Gland Health Risk of High-Yielding Dairy Cows.

Simple SummaryThe objective of the study was to realize the function of blood gas parameter in relation to the health of high-yielding dairy cows. The study showed that most blood gas parameters differ across the three vessels (coccygeal artery, coccygeal vein, and mammary vein). The associations of oxygen-related variables in the mammary vein are negatively correlated with the levels of malondialdehyde, lactate dehydrogenase, and plasmin in the milk. In the present study, we used blood gas profile to identify the mammary gland health condition in lactating dairy cows.The blood gas profile is a routine method in the rapid disease diagnosis of farm animals, yet its potential in evaluating mammary health status of dairy cows remains to be investigated. This study was conducted to learn the potential of the blood gas parameter regarding the mammary gland health status in lactating dairy cows. Twenty animals were divided into two groups, the H-SCC group (milk SCC > 122 k/mL) and L-SCC group (milk SCC < 73.8 k/mL), to compare blood gas profiles from different blood vessels and to identify the key parameters associated with milk somatic cell count. H-SCC cows are higher in malondialdehyde content, but lower in SOD and T-AOC activities in the milk, compared to the L-SCC group. In terms of blood gas parameters, most differ across the three vessels, including K+, CO2 pressure, O2 pressure, HCO3−, base excess in the extracellular fluid compartment, and saturation of O2. The Pearson correlation analysis showed that oxygen-related variables in the mammary vein, including oxygen concentrations, O2 pressure, and saturation of O2, are negatively correlated with levels of malondialdehyde, lactate dehydrogenase, and plasmin in the milk. Our study revealed that oxygen-related variables in the mammary vein can be a marker in suggesting mammary-gland health status in high-yielding cows.

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.

Evaluation of the effect of birth type on blood gas and Apgar scores in newborn kids

The present study was conducted to investigate the effect of eutocia and dystocia on blood gas and Apgar scores in Aleppo goat kids. A total of 40 kids were used in the study. Kids were divided into 2 groups according to the type of birth. The first group of the study (Group 1, n=20) consisted of kids born as a result of eutocia, and the second group of the study (Group 2, n=20) was formed as a result of dystocia. Apgar scores (appearance, pulse, grimace, attitude, respiration) were evaluated at 0, 5, and 15 minutes postpartum from kids in both study groups, and blood samples were taken from blood gas injectors and blood gas profiles (pH, pCO2, pO2, HCO3) were obtained. The obtained data were analyzed with Mann-Whitney-U and Friedman post-hoc bonferroni. Spearman correlation coefficients were calculated to determine the relationships between measurements. A statistically significant difference was observed between the groups in the Apgar score at 0, 5 and 15 minutes and in the blood gas measurements of pH, pO2, pCO2, and HCO3 at 0, 5 and 15 minutes (p

Voluntary daily fluctuation in dry matter intake is associated to feedlot performance, feeding behavior and rumen morphometrics in beef cattle

• Cattle from low-DMI fluctuation group improved feedlot performance. • High-DMI fluctuation pens took longer to eat and ruminate a kg of both DM and NDF. • High-DMI fluctuation negatively impacted blood gas profile and rumenitis scores. The degree of day-to-day fluctuation in voluntary DMI may influence feeding and rumination behavior, with potential impacts on feedlot performance. The purpose of this study was to evaluate the effect of voluntary fluctuation of DMI by pens of cattle given free-choice access to feed. These responses were measured in a dataset compiled from ten feedlot studies from 2006 to 2015. The data set included a total of 956 16-mo-old Bos indicus bulls (343.60 ± 44.15 kg) randomly allocated to a total of 238 pens (4 bulls per pen); cattle were fed high concentrate feedlot diets for an average of 106-d (minimum: 84-d; maximum: 140-d), and slaughtered at a commercial abattoir. To balance statistically for differences in animal background, type, and condition, for each year within treatments, pens were allocated into one of two groups: below or above the mean DMI fluctuation. The low- and the high- DMI fluctuation groups had day-to-day fluctuation in DMI of 5.18% and 6.22%, respectively ( P < 0.01) or 0.45 vs. 0.55 kg/day (P < 0.01). Data were analyzed using a generalized linear mixed model procedure with the statistical software R. Cattle within the low-DMI fluctuation group had 4.2% greater (1.48 vs. 1.42 kg/d; P < 0.01) ADG and 3.7% greater (2.26 vs. 2.18 kg/d; P < 0.001) DMI expressed as a percentage of mean BW; but no significant effect was detected for G:F ratio ( P = 0.91). Animals from the low-DMI fluctuation group had greater ( P ≤ 0.01) daily increase in LM area and 12 th rib fat as well as heavier HCW (266 vs. 263 kg; P = 0.04). Cattle from low-DMI fluctuation group consumed more DMI per meal ( P < 0.001) and had greater NDF intake ( P = 0.01) than cattle from the high-DMI fluctuation group. In addition, animals from high-DMI fluctuation pens took longer to consume and ruminate each kg of diet DM ( P < 0.01) and NDF ( P < 0.01) compared to cattle from low-DMI fluctuation group. A effect ( P = 0.04) was detected for blood base excess (BEB) with low-DMI fluctuation pens having a greater concentration of BEB. Moreover, the low-DMI fluctuation group tended to have ( P = 0.07) lower rumenitis scores. Although causal effects cannot be differentiated from casual relationships in this study, the fact that reduced daily DMI fluctuation was related to greater ADG and carcass weight makes this measurement relevant as an index of performance, and efforts to reduce DMI variability are warranted. Reducing day-to-day fluctuations in DMI should improve cattle health and performance.

Prone Positioning as a Bridge to Recovery From Refractory Hypoxemia After Oversized Lung Transplant

BackgroundSize matching is an important challenge in lung transplantation. Although the survival rate after lung transplantation with an oversized allograft was improved, it is associated with substantial immediate postoperative morbidity and mortality. Prone positioning is a rescue therapy showing improved outcomes in acute respiratory distress syndrome. We present a case of immediate postoperative refractory hypoxemia after oversized lung transplantation treated by prone positioning. MethodsA 62-year-old man was transferred to our hospital by our extracorporeal membrane oxygenation (ECMO) transport team because of acute exacerbation of idiopathic pulmonary fibrosis. He underwent bilateral lung transplantation through bilateral anterior thoracotomy. For size matching between donor and recipient, multiple wedge resection and lingular segmentectomy were performed, but an oversized lung was implanted. On the immediate postoperative day, chest radiography revealed haziness in the left lower quadrant and the patient had an increased O2 requirement; he could not be weaned from venovenous (VV) ECMO. Chest computed tomography revealed left lower lobar atelectasis and primary graft dysfunction. To revert the atelectatic portion, improve ventilation/perfusion mismatch, and avoid high ventilation pressure, we performed the recruitment maneuver. Despite this, his blood gas profile did not improve. Therefore, we applied prone positioning with VV ECMO. After conversion to the prone positioning, the hypoxia corrected and the tidal volume increased. After 20 hours, he was changed to the supine position. Thereafter, arterial blood gas analyses were stable and he could be weaned from ECMO. He was discharged on postoperative day 57 and maintained good respiratory function. ConclusionsThis case demonstrated the safety and feasibility of prone positioning during the immediate postoperative period after lung transplant by bilateral anterior thoracotomy. Prone positioning successfully reversed postoperative atelectasis and improved primary graft dysfunction after oversized lung transplant.

The impact of fibropapillomatosis on clinical characteristics, blood gas, plasma biochemistry, and hematological profiles in juvenile green turtles ( Chelonia mydas)

Fibropapillomatosis (FP) is a tumor- forming disease that afflicts all marine turtles and is the most common in green turtles (Chelonia mydas). In this study, the morphometric characteristics, blood gas, biochemistry, and hematological profiles of 28 (6 FP-positive and 22 FP-negative) green turtles from the coast of Taiwan were investigated. The results indicated that body weight ( P &lt; 0.001) and curved carapace length (CCL; P &lt; 0.001) in green turtles with FP were significantly higher than in turtles without FP. Furthermore, green turtles with FP had a significantly lower value of hemoglobin (HB; P = 0.010) and packed cell volume (PCV; P = 0.005) than turtles without FP. Blood cell counts of white blood cells (WBC; P = 0.008) and lymphocytes ( P = 0.022) were observed with significant difference; green turtles with FP had lower counts than turtles without FP. In addition, turtles with FP had significantly higher pH ( P = 0.036), base excess in extracellular fluid (BEecf; P = 0.012), bicarbonate (HCO3– ; P = 0.008), and total carbon dioxide (TCO2 ; P = 0.025) values than turtles without FP. The findings of this study provide valuable clinical parameters for the medical care of the species in sea turtle rehabilitation centers and help us to understand the physiological response of green turtles to different tumor-forming conditions.

Feedlot performance and rumen morphometrics of Nellore cattle adapted to high-concentrate diets over periods of 6, 9, 14 and 21 days

The energy content of finishing diets offered to feedlot cattle may vary across countries. We assumed that the lower is the energy content of the finishing diet, the shorter can be the adaptation period to high-concentrate diets without negatively impacting rumen health while still improving feedlot performance. This study was designed to determine the effects of adaptation periods of 6, 9, 14 and 21 days on feedlot performance, feeding behaviour, blood gas profile, carcass characteristics and rumen morphometrics of Nellore cattle. The experiment was designed as a completely randomised block, replicated 6 times, in which 96 20-month-old yearling Nellore bulls (391.1 ± 30.9 kg) were fed in 24 pens (4 animals/pen) according to the adaptation period adopted: 6, 9, 14 or 21 days. The adaptation diets contained 70%, 75% and 80.5% concentrate, and the finishing diet contained 86% concentrate. After adaptation, one animal per pen was slaughtered (n = 24) for rumen morphometric evaluations and the remaining 72 animals were harvested after 88 days on feed. Orthogonal contrasts were used to assess linear, quadratic and cubic relationships between days of adaptation and the dependent variable. Overall, as days of adaptation increased, final BW (P = 0.06), average daily gain (ADG) (P = 0.07), hot carcass weight (P = 0.04) and gain to feed ratio (G : F) (P = 0.07) were affected quadratically, in which yearling bulls adapted by 14 days presented greater final BW, ADG, hot carcass weight and improved G : F. No significant (P > 0.10) days of adaptation effect was observed for any of feeding behaviour variables. As days of adaptation increased, the absorptive surface area of the rumen was affected cubically, where yearling bulls adapted by 14 days presented greater absorptive surface area (P = 0.03). Thus, Nellore yearling bulls should be adapted by 14 days because it led to improved feedlot performance and greater development of rumen epithelium without increasing rumenitis scores.

Different combinations of sodium monensin and virginiamycin during feedlot finishing of Nellore cattle

Context The use of two feed additives, to maximise rumen fermentation, in finishing diets offered to feedlot cattle may positively impact performance. Aims This study, conducted at the São Paulo State University feedlot, Botucatu campus, Brazil, was designed to evaluate the effects of the combined use of monensin (MON; 30 mg/kg of dry matter; (DM)) and virginiamycin (VM; 25 mg/kg of DM) in high-concentrate diets during the adaptation and finishing periods on feedlot performance, carcass traits, feeding behaviour, blood gas profile, rumen morphometrics and apparent total tract digestibility of nutrients of Nellore cattle. Methods The experiment was designed as a completely randomised block, replicated six times (3 bulls/pen), in which 72 20 months of age yearling Nellore bulls (388.0 ± 31.1 kg) were fed in 24 pens for 90 days according to the treatments: (1) MON during the entire feeding period (T1), (2) MON + VM during adaptation and only VM during the finishing period (T2), (3) MON + VM during the entire feeding period (T3), and (4) VM during the adaptation and MON + VM during the finishing period (T4). The adaptation program consisted of ad libitum feeding of three diets over the adaptation period of 19 days with concentrate level increasing from 69% to 84% of diet DM. Key results Overall, bulls fed on T2 had a greater DM intake (P &amp;lt; 0.01), final bodyweight (P = 0.04), average daily gain (P = 0.03), hot carcass weight (P &amp;lt; 0.01), final Longissimus muscle area (P = 0.05), Longissimus muscle area daily gain (P = 0.01), improved carcass G:F (P &amp;lt; 0.01) and increased dressing percentage (P &amp;lt; 0.01). Similarly, bulls fed on T2 were faster to consume 1 kg of either DM (P &amp;lt; 0.01) or neutral detergent fibre (P &amp;lt; 0.01) after 60 days on feed. Furthermore, bulls fed on T2 presented a greater (P = 0.05) cell proliferation index in the rumen papillae. Conclusions According to the results, Nellore yearling bulls should be fed high-concentrate diets containing MON and VM during adaptation, and only VM during the finishing period to improve overall feedlot performance. Implications The use of both MON and VM proved to be helpful only during the adaptation period.

Serum Bicarbonate as a Surrogate for pH in Hemodialysis: A Pilot Study

Rationale & ObjectiveExcess morbidity and mortality are associated with both high and low serum bicarbonate levels in epidemiologic studies of patients with end-stage kidney disease (ESKD) receiving hemodialysis. The Kidney Disease Outcomes Quality Initiative (KDOQI) recommends modifying dialysate bicarbonate concentration to achieve a predialysis serum bicarbonate level ≥ 22 mmol/L, measured as total carbon dioxide (CO2). This practice assumes that total CO2 is an adequate surrogate for acid-base status, yet its surrogacy performance is unknown in ESKD. We determined acid-base status at the beginning and end of hemodialysis using total CO2 and pH and tested whether total CO2 is an appropriate surrogate for acid-base status.Study DesignPilot study.Setting & Participants25 veterans with ESKD receiving outpatient hemodialysis.Tests ComparedpH, calculated bicarbonate level, and total CO2.OutcomesThe proportion of paired samples for which total CO2 misclassified acid-base status according to pH was determined. Bias of total CO2 was evaluated using Bland-Altman plots, comparing it to calculated bicarbonate.ResultsAmong 71 samples, mean pH was 7.41 ± 0.03 predialysis and 7.48 ± 0.05 postdialysis. Compared with interpretation of full blood gas profiles, 9 of 25 (36%) participants were misclassified as acidemic using predialysis total CO2 measures alone (total CO2 < 22 mmol/L but pH ≥ 7.38); 1 (4%) participant was misclassified as alkalemic (total CO2 > 26 mmol/L but pH ≤ 7.42). Among paired samples in which predialysis total CO2 was < 22 mmol/L, the corresponding pH was acidemic (< 7.38) in just 3 of 13 (23%) instances.LimitationsSmall, single-center, entirely male cohort.ConclusionsA majority of participants became alkalemic during routine hemodialysis despite arriving with normal pH. 10 of 25 (40%) participants’ acid-base status was misclassified using total CO2 measurements alone; the majority of predialysis total CO2 values that would trigger therapeutic modification according to practice guidelines did not have acidemia when assessed using pH. Efforts to improve dialysis prescription require recognition that total CO2 may not be reliable for interpreting acid-base status in hemodialysis patients.

Shorter defibrillation interval promotes successful defibrillation and resuscitation outcomes

AimCurrent cardiopulmonary resuscitation guidelines recommend performing defibrillation every 2 min during resuscitation. This study aimed to compare the rate of successful defibrillation using 1- and 2-min defibrillation intervals. MethodsTwenty-six pigs were randomly assigned to 1- or 2-min interval groups. After inducing ventricular fibrillation (VF), we observed pigs for 2 min. Thereafter, basic life support was initiated with a 30:2 compression-to-ventilation ratio for 8 min. Defibrillation was performed with an energy of 2 J/kg at 10 min after VF and was repeated every 1 or 2 min according to randomization. Advanced cardiac life support, including continuous chest compression with ventilation every 6 s and intravenous injection of 1 mg epinephrine every 3 min, was performed until the return of spontaneous circulation (ROSC) or until 20 min after VF induction. Haemodynamic parameters and baseline arterial blood gas profiles were compared between groups. ROSC, 24 -h survival, and the neurologic deficit score (NDS) were evaluated at 24 h. ResultsHaemodynamic parameters during resuscitation and baseline arterial blood gas profiles did not differ between groups. ROSC was more frequently observed in the 1-min interval group (p = 0.047). Time to ROSC was not different between groups (p = 0.054). The 24 -h survival was higher (p = 0.047) and NDS at 24 h was lower (92 ± 175) in the 1-min interval group than in the 2-min interval group (272 ± 190) (p = 0.028). ConclusionsDefibrillation success and resuscitation outcomes were superior when using a 1-min defibrillation interval in animal models of cardiac arrest.

Restricted versus step-up dietary adaptation in Nellore bulls: Effects over periods of 9 and 14 days on feedlot performance, feeding behavior and rumen morphometrics

Previous studies have shown that beef cattle can be adapted for 14 days to high-energy diets; however, the effects of adaptation periods less than 14 days on feedlot performance have not been documented in the literature. In the present study, the effects of restricted intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in concentrate content (step-up) over periods of 9 days and 14 days on feedlot performance, feeding behavior, blood gas profile rumen morphometrics, nutrients digestibility and carcass characteristics of Nellore cattle were evaluated. One-hundred twenty 24 month-old Nellore bulls (361 ± 30 kg) were randomly allocated in 24 pens and fed for 84 days in a completely randomized block design with a 2 × 2 factorial arrangement of treatments: adaptation using both 9-day and 14-day step-up protocol, and 9-day and 14-day restriction protocol. Each treatment was replicated 6 times. One bull per pen was slaughtered at the end of adaptation period for ruminal evaluations. Overall, no main effect of protocols or adaptation length was observed for any of feedlot performance or carcass traits variables evaluated, with the exception of gain to feed ratio (G:F). Bulls on restriction protocol had improved G:F (P = 0.04) when compared to cattle adapted by step-up protocol. Regarding rumenitis score, there was no main effect of protocols and adaptation length (P > 0.05). For rumen morphometrics, an interaction between the effect of adaptation length and period was observed (P = 0.02) for absorptive surface area (ASA), where at the end of the adaptation period, Nellore bulls adapted for 14 days presented larger ASA than the ones adapted for 9 days; however, at the end of the finishing period, ASA from animals adapted for 14 days was similar to the ones adapted for 9 days. Thus, Nellore yearling bulls should be adapted in 14 days regardless of the protocol adopted (step-up or restriction).

Development of Clinical Criteria for Functional Assessment to Predict Primary Nonfunction of High-Risk Livers Using Normothermic Machine Perfusion.

Increased use of high‐risk allografts is critical to meet the demand for liver transplantation. We aimed to identify criteria predicting viability of organs, currently declined for clinical transplantation, using functional assessment during normothermic machine perfusion (NMP). Twelve discarded human livers were subjected to NMP following static cold storage. Livers were perfused with a packed red cell–based fluid at 37°C for 6 hours. Multilevel statistical models for repeated measures were employed to investigate the trend of perfusate blood gas profiles and vascular flow characteristics over time and the effect of lactate‐clearing (LC) and non‐lactate‐clearing (non‐LC) ability of the livers. The relationship of lactate clearance capability with bile production and histological and molecular findings were also examined. After 2 hours of perfusion, median lactate concentrations were 3.0 and 14.6 mmol/L in the LC and non‐LC groups, respectively. LC livers produced more bile and maintained a stable perfusate pH and vascular flow >150 and 500 mL/minute through the hepatic artery and portal vein, respectively. Histology revealed discrepancies between subjectively discarded livers compared with objective findings. There were minimal morphological changes in the LC group, whereas non‐LC livers often showed hepatocellular injury and reduced glycogen deposition. Adenosine triphosphate levels in the LC group increased compared with the non‐LC livers. We propose composite viability criteria consisting of lactate clearance, pH maintenance, bile production, vascular flow patterns, and liver macroscopic appearance. These have been tested successfully in clinical transplantation. In conclusion, NMP allows an objective assessment of liver function that may reduce the risk and permit use of currently unused high‐risk livers.

Establishing blood gas ranges in healthy bovine neonates differentiated by age, sex, and breed type

Calf mortality and morbidity commonly occurs within the first month of life postpartum. Standard health ranges are invaluable aids in diagnostic veterinary medicine to confirm normal or the degree and nature of abnormal parameters in (sub)clinically ill animals. Extensive research has indicated significant differences between the physiologies of neonate and adult cattle, particularly for blood parameters such as pH, base excess, anion gap, and bicarbonate (HCO3-). The objective of this research was to determine the influence of age, sex, and breed type, in addition to environmental factors, on the normal blood gas profiles of neonatal calves, and thus develop a scientifically validated reference range accounting for any significant factors. The study was conducted on healthy neonatal calves (n = 288), and completed over a 2-yr period. Individual calf blood gas analysis was conducted for parameters of pH, base excess, Na+, K+, Ca2+, Cl-, glucose, total hemoglobin, HCO3-, pCO2, anion gap, strong ion difference, and hematocrit levels. Regression procedures examined the combined effect of year, farm, age, breed type, sex, and hours postfeeding on each variable. Significant effects were observed for age, sex, and breed type on several of the blood gas variables. Furthermore, year, farm, and hours postfeeding appeared to have less of an influence on neonatal bovine blood gas profiles. Consequently, specific ranges based on the neonate's age, sex, and breed type will allow for more detailed and accurate diagnosis of health and ill health in neonatal calves.