Blood Carbon Dioxide Research Articles

Effects of restrictive fluid resuscitation on the clinical efficacy of treating traumatic hemorrhagic shock combined with traumatic coagulopathy

This study aims to assess the clinical efficacy of limited fluid resuscitation on traumatic hemorrhagic shock combined with traumatic coagulopathy. A cohort of 120 patients with traumatic hemorrhagic shock complicated with traumatic coagulopathy at admission were divided into two groups based on their emergency fluid resuscitation: the study group (received restrictive fluid resuscitation) and the control group (received conventional fluid resuscitation). Then, the incidence of complications, coagulation parameters, blood gas parameters and electrolyte parameters between the two groups were compared. The incidence of complications in the study group was 6.67%, which was significantly lower than the 20.00% observed in the control group (p < 0.05). Before resuscitation, there was no significant difference in coagulation parameters, blood gas parameters and electrolyte parameters between the two groups (p > 0.05), and in both groups, before and after resuscitation, the coagulation parameters after resuscitation were higher than those before resuscitation, blood gas parameters were lower than those before resuscitation, Mg2+, Cl− and Na+ levels were higher than those before resuscitation, K+ was lower than that before resuscitation, and the difference had statistical significance (p < 0.05). After resuscitation, the coagulation parameters in the study group were significantly lower than those in the control group, the BL (Blood Lactic Acid) and PaCO2 (partial pressure of carbon dioxide in arterial blood) levels in the study group were lower than those in the control group, the BE (base excess) and PaO2 levels were higher than those in the control group, and the differences were statistically significant (p < 0.05). However, after resuscitation, we found no significant difference in electrolyte parameters between both groups (p > 0.05). Restrictive fluid resuscitation was found to significantly enhance coagulation and blood gas function, stabilize water and electrolyte balance and reduce complications in traumatic hemorrhagic shock patients complicated with traumatic coagulopathy. These findings hold substantial clinical significance and merit further exploration.

A matter of sex-persistent predictive value of MECKI score prognostic power in men and women with heart failure and reduced ejection fraction: a multicenter study.

A sex-based evaluation of prognosis in heart failure (HF) is lacking. We analyzed the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score registry, which includes HF with reduced ejection fraction (HFrEF) patients. A cross-validation procedure was performed to estimate weights separately for men and women of all MECKI score parameters: left ventricular ejection fraction (LVEF), hemoglobin, kidney function assessed by Modification of Diet in Renal Disease, blood sodium level, ventilation vs. carbon dioxide production slope, and peak oxygen consumption (peakVO2). The primary outcomes were the composite of all-cause mortality, urgent heart transplant, and implant of a left ventricle assist device. The difference in predictive ability between the native and sex recalibrated MECKI (S-MECKI) was calculated using a receiver operating characteristic (ROC) curve at 2 years and a calibration plot. We retrospectively analyzed 7,900 HFrEF patients included in the MECKI score registry (mean age 61 ± 13 years, 6,456 men/1,444 women, mean LVEF 33% ± 10%, mean peakVO2 56.2% ± 17.6% of predicted) with a median follow-up of 4.05 years (range 1.72-7.47). Our results revealed an unadjusted risk of events that was doubled in men compared to women (9.7 vs. 4.1) and a significant difference in weight between the sexes of most of the parameters included in the MECKI score. S-MECKI showed improved risk classification and accuracy (area under the ROC curve: 0.7893 vs. 0.7799, p = 0.02) due to prognostication improvement in the high-risk settings in both sexes (MECKI score >10 in men and >5 in women). S-MECKI, i.e., the recalibrated MECKI according to sex-specific differences, constitutes a further step in the prognostic assessment of patients with severe HFrEF.

Analysis of mixed rhythm and its dynamics in closed-loop respiratory control system driven by electromagnetic induction

The pre-Bötzinger complex is a crucial region for generating respiratory rhythms in mammals. Peripheral chemoreceptors have a significant influence on respiratory rhythm by monitoring changes in blood oxygen concentration and carbon dioxide concentration. This study introduces a closed-loop respiratory control model, which is driven by electromagnetic induction and based on the activation of pre-Bötzinger complex neurons. The model incorporates various factors including the motor pool, lung volume, lung oxygen, blood oxygen, and chemoreceptors. The response of the system subjected to the same hypoxic perturbation under different electromagnetic induction is studied, and the control effect of magnetic flux feedback coefficient on the recovery of mixed rhythms is investigated. Using bifurcation analysis and numerical simulations, it is found that the magnetic flux feedback coefficient has a significant influence on the ability to recover respiratory rhythm. The dynamic mechanism of the magnetic flux feedback coefficient on different hypoxic responses in closed-loop systems are revealed. Dynamic analysis indicates that under certain electromagnetic induction, the mixed bursting rhythm in the closed-loop system can autoresuscitate if the bifurcation structure before and after applying hypoxia perturbation are completely identical. However, when the bifurcation structure before and after applying hypoxia perturbation are different, the mixed bursting rhythm in the system cannot autoresuscitate. In addition, for the cases where automatic recovery is not achieved under mild electromagnetic induction, increasing the magnetic flux feedback coefficient appropriately can lead the system to autoresuscitate, which is closely related to the Hopf bifurcation and fold bifurcation of limit cycle. This study contributes to understanding the influence of the interaction between the central respiratory and peripheral chemoreceptive feedback on respiratory rhythm, as well as the control effect of external induction on the hypoxic response.

Effectiveness of Structured Teaching Programme on Knowledge Regarding Arterial Blood Gas Analysis among Nursing Students in Chitwan, Nepal A Pre-experimental One Group Pretest Post-test Design

Background: Arterial blood gas (ABG) analysis measures blood pH, oxygen (O2), and carbon dioxide (CO2) levels. Normal pH is 7.35-7.45, PaO2 ranges from 70-100 mm Hg, PaCO2 is 35-45 mm Hg, and SaO2 is 93-98%. HCO3 normal value is 22-26 meq/l. This study assesses the effectiveness of a structured teaching program on arterial blood gas analysis knowledge among nursing students. Methods: A pre-experimental study with a one-group pretest-posttest design evaluated the effectiveness of a structured teaching program on Arterial Blood Gas analysis knowledge among nursing students from two Purbanchal University-affiliated colleges. Narayani Samudayik Nursing College was chosen using a probability-based simple random sampling lottery method. Enumerative sampling was employed to select respondents for the study. Results: The study found that 87% of respondents initially had an average knowledge level of arterial blood gas analysis, with 13% having adequate knowledge. After intervention, 82.6% demonstrated adequate knowledge, and 17.4% maintained an average level. Mean knowledge scores significantly increased from 67.15 to 87.7 in pretest and posttest, respectively (p<0.001). The results affirm the intervention's effectiveness in improving participants' understanding of arterial blood gas analysis..Conclusion: Most respondents had average knowledge of ABG analysis. Following the structured teaching program, the majority achieved adequate knowledge, demonstrating its significant positive impact in enhancing nursing students' unde standing of ABG analysis.

Characterization of a Waveguide with 45 Degrees Reflectors for the Detection of Carbon Dioxide

This paper investigates the characteristics of the angle of incidence of a waveguide with 45 degrees reflectors. Non-dispersive infrared (NDIR) gas sensors consist of an infrared source, a waveguide, and an infrared detector. The waveguide especially plays a part in an infrared path and gas cell. According to the Beer-Lambert law, the NDIR sensor with longer ray traveling path shows a higher response to the target gas. Also of particular interest is that the normal incidence ratio toward an infrared detector enhances the NDIR sensor selectivity for the target gases as well as the sensitivity. While there has been significant research on the effect on sensitivity by designing waveguide structures or ray traveling distance, this paper focuses on understanding the incidence of light toward the infrared detector by the waveguide with 45 degrees reflector and how this affects the selectivity of the sensor. A Ray tracing simulation is adopted to analyze the effect of the number of 45 degrees reflectors on the distribution of the incidence. Furthermore, a non-dispersive infrared gas sensor is applied to measure how the number of the reflectors affect to the selectivity for the target gas. The results reveal the enhancement of the selectivity by the reflectors.AcknowledgementsThis work was supported by the Korea Innovation Foundation(INNOPOLIS) grant funded by the Korea government(MSIT) (2020-DD-UP-0348). This study has been conducted with the support of the Korea Institute of Industrial Technology as "Development and commercialization for clean hydrogen production/storage and CO2 monitoring system in the field of industrial complex" (Kitech EH-23-0012) This work was supported by the Technology Innovation Program (155736, Development of Miniaturized Sensor Module Technology for Non-invasive Arterial Blood Carbon Dioxide Real-time Monitoring) funded By the Ministry of Trade, Industry & Energy(MOTIE, Korea). Figure 1

Self-calibrating dual-sensing electrochemical sensors for accurate detection of carbon dioxide in blood.

A paper-based electrochemical dual-function biosensor capable of determining pH and TCO2 was synthesized for the first time using an iridium oxide pH electrode and an all-solid-state ion electrode (ASIE). In the study, to obtain highly reliable results, the biosensor was equipped with a real-time pH correction function before TCO2 measurements. Compared to traditional liquid-filling carbon dioxide detection sensors, the utilization of ferrocene endows our novel sensor with abundant positive sites, and thus greatly improves its performance. Conversely, the introduction of MXene with conductivity close to that of metals reduces electrode resistance, which is beneficial for accelerating the electrochemical reaction of the sensor and reducing LOD. After optimization, the detection range of TCO2 is 0.095 nM-0.66 M, with a detection limit of as low as 0.023 nM. In addition, the sensor was used in real serum sample-spiked recovery experiments and comparison experiments with existing clinical blood gas analyzers, which confirmed the effectiveness of its clinical application. This study provides a method for the rational design of paper-based electrochemical biosensors and a new approach for the clinical detection of blood carbon dioxide.

Acid-Sensing Ion Channels' Immunoreactivity in Nerve Profiles and Glomus Cells of the Human Carotid Body.

The carotid body is a major peripheral chemoreceptor that senses changes in arterial blood oxygen, carbon dioxide, and pH, which is important for the regulation of breathing and cardiovascular function. The mechanisms by which the carotid body senses O2 and CO2 are well known; conversely, the mechanisms by which it senses pH variations are almost unknown. Here, we used immunohistochemistry to investigate how the human carotid body contributes to the detection of acidosis, analyzing whether it expresses acid-sensing ion channels (ASICs) and determining whether these channels are in the chemosensory glomic cells or in the afferent nerves. In ASIC1, ASIC2, and ASIC3, and to a much lesser extent ASIC4, immunoreactivity was detected in subpopulations of type I glomus cells, as well as in the nerves of the carotid body. In addition, immunoreactivity was found for all ASIC subunits in the neurons of the petrosal and superior cervical sympathetic ganglia, where afferent and efferent neurons are located, respectively, innervating the carotid body. This study reports for the first time the occurrence of ASIC proteins in the human carotid body, demonstrating that they are present in glomus chemosensory cells (ASIC1 < ASIC2 > ASIC3 > ASIC4) and nerves, presumably in both the afferent and efferent neurons supplying the organ. These results suggest that the detection of acidosis by the carotid body can be mediated via the ASIC ion channels present in the type I glomus cells or directly via sensory nerve fibers.

Neurogenic Regulation of Cerebral Blood Flow

The brain has a well-developed vascular network, which allows it to consume up to 15% of the cardiac output with a low mass relative to the whole-body weight. Normally, the metabolic demands of the brain depend considerably on the intensity of functioning of its different departments, which requires constant regulation of the local blood flow level. On the other hand, the state of systemic hemodynamics can have a significant impact on the organ blood flow. Complex and multilevel mechanisms of the regulation of organ cerebral blood flow are aimed at minimizing the possible adverse effects of systemic hemodynamics impairment. The importance of precise and prompt regulation of cerebral blood flow is reinforced by the absence of energy reserves or substrates for its autonomous production in the nervous tissue. The main mechanisms of cerebral blood flow regulation include: myogenic regulation, influence of local humoral influences and vasoactive substances (hormones, metabolites) of systemic blood flow, changes in blood gas composition (increase or decrease in blood oxygen or carbon dioxide tension). In addition, endothelium-dependent mechanisms of regulation are distinguished. Finally, one more level of cerebral arterial tone regulation is represented by the effect of neurotransmitters released from vasomotor fibers terminals of sympathetic and parasympathetic sections of autonomic nervous system, as well as from subcortical neurons and cortical interneurons terminals. In the present review, the principles of neurogenic regulation of cerebral blood flow are considered. The neurogenic regulation of vascular tone is the most complex regulatory circuit. The autonomic innervation of cerebral vessels has significant features that distinguish it from that in most other organs of the great circulatory circle. In addition to the autonomic innervation proper, the vessels of the brain receive sensory innervation, and the small intracerebral arterioles are also innervated -directly by subcortical neurons and cortical interneurons. In this connection, a deeper understanding of the molecular mechanisms of the neurogenic regulation of cerebral blood flow may serve as a basis for the development of new methods of treatment of severe brain diseases based on neuromodulation in the long term.

Death by Neurologic Criteria in Children Undergoing Extracorporeal Cardiopulmonary Resuscitation: Retrospective Extracorporeal Life Support Organization Registry Study, 2017-2021.

To determine factors associated with brain death in children treated with extracorporeal cardiopulmonary resuscitation (E-cardiopulmonary resuscitation). Retrospective database study. Data reported to the Extracorporeal Life Support Organization (ELSO), 2017-2021. Children supported with venoarterial extracorporeal membrane oxygenation (ECMO) for E-cardiopulmonary resuscitation. None. Data from the ELSO Registry included patient characteristics, blood gas values, support therapies, and complications. The primary outcome was brain death (i.e., death by neurologic criteria [DNC]). There were 2,209 children (≥ 29 d to < 18 yr of age) included. The reason for ECMO discontinuation was DNC in 138 patients (6%), and other criteria for death occurred in 886 patients (40%). Recovery occurred in 1,109 patients (50%), and the remaining 76 patients (4%) underwent transplantation. Fine and Gray proportional subdistribution hazards' regression analyses were used to examine the association between variables of interest and DNC. Age greater than 1 year ( p < 0.001), arterial blood carbon dioxide tension (Pa co2 ) greater than 82 mm Hg ( p = 0.022), baseline lactate greater than 15 mmol/L ( p = 0.034), and lactate 24 hours after cannulation greater than 3.8 mmol/L ( p < 0.001) were independently associated with greater hazard of subsequent DNC. In contrast, the presence of cardiac disease was associated with a lower hazard of subsequent DNC (subdistribution hazard ratio 0.57 [95% CI, 0.39-0.83] p = 0.004). In children undergoing E-cardiopulmonary resuscitation, older age, pre-event hypercarbia, higher before and during ECMO lactate levels are associated with DNC. Given the association of DNC with hypercarbia following cardiac arrest, the role of Pa co2 management in E-cardiopulmonary resuscitation warrants further studies.

Observer‐based non‐fragile event‐triggered control of extra‐corporeal blood circulation process in finite‐time interval

AbstractAn observer‐based event‐triggered non‐fragile control problem for regulating the levels of oxygen and carbon dioxide (O and CO) in patients blood during the extra‐corporeal blood circulation (ECC) process with random communication packet losses is explored in this work. The main intention of this work is to design an observer‐based event‐triggered and non‐fragile controller for ensuring the finite‐time boundedness criterion for the resulting system with mixed and passivity performance index over a finite interval of time. In addition to the limited bandwidth of the channels, such random packet losses might occur simultaneously between the sensors and the controllers, and between the controllers and the actuators. Unlike most studies in the literature, we have found that, since the controller‐actuator link has packet dropouts, the observer's control input differs from that of the plant. The sufficient conditions derived are presented in a linear matrix inequalities frame work. Finally, simulation results are used to validate the efficacy of the proposed control method. The results show that the proposed observer‐based event‐triggered non‐fragile controller keeps the blood gases within physiological limits during a stable ECC process.

Efficacy of different respiratory supports to prevent hypoxia during flexible bronchoscopy in patients of COPD: a triple-arm, randomised controlled trial

BackgroundPatients with chronic-obstructive-pulmonary-disease (COPD) undergo bronchoscopy for various reasons, and are at relatively higher risk of complications. This study evaluated the efficacy of non-invasive ventilation (NIV) and high-flow-oxygen-therapy (HFOT) compared...

Prehospital Advanced Airway Management and Ventilation for Out-of-Hospital Cardiac Arrest with Prehospital Return of Spontaneous Circulation: A Prospective Observational Cohort Study in Japan

Background The relationship among advanced airway management (AAM), ventilation, and oxygenation in patients with out-of-hospital cardiac arrest (OHCA) who achieve prehospital return of spontaneous circulation (ROSC) has not been validated. This study was designed to evaluate ventilation and oxygenation for each AAM technique (supraglottic devices [SGA] or endotracheal intubation [ETI]) using arterial blood gas (ABG) results immediately after hospital arrival. Methods This observational cohort study, using data from the Japanese Association for Acute Medicine OHCA Registry, included patients with OHCA with prehospital and hospital arrival ROSC between July 1, 2014, and December 31, 2019. The primary outcomes were the partial pressure of carbon dioxide in the arterial blood (PaCO2) and partial pressure of oxygen in the arterial blood (PaO2) in the initial ABG at the hospital for each AAM technique (SGA or ETI) performed by paramedics. The secondary outcome was favorable neurological outcome (cerebral performance category [CPC] 1 or 2) for specific PaCO2 levels, which were defined as good ventilation (PaCO2 ≤45 mmHg) and insufficient ventilation (PaCO2 >45 mmHg). Results This study included 1,527 patients. Regarding AAM, 1,114 and 413 patients were ventilated using SGA and ETI, respectively. The median PaCO2 and PaO2 levels were 74.50 mmHg and 151.35 mmHg in the SGA group, while 66.30 mmHg and 173.50 mmHg in the ETI group. PaCO2 was significantly lower in the ETI group than in the SGA group (12.55 mmHg; 95% CI 15.27 to 8.20, P-value < 0.001), while no significant difference was found in PaO2 by multivariate linear regression analysis. After stabilizing inverse probability of weighting (IPW), the adjusted odds ratio for favorable neurological outcome at 1 month was significant in the good ventilation group compared to the insufficient ventilation cohort (adjusted odds ratio = 2.12, 95%CI: 1.40 to 3.19, P value < 0.001). Conclusion The study showed that in OHCA patients with prehospital ROSC, the PaCO2 levels in the initial ABG were lower in the group with AAM by ETI than in the SGA group. Furthermore, patients with prehospital ROSC and PaCO2 ≤45 mmHg on arrival had an increased odds of favorable neurological outcome after stabilized IPW adjustment.

Arterial blood analysis of healthy residents in Huamachuco, Peru (3,164 m): a cross-sectional study.

Background: Given that arterial blood gas is affected by altitude and ethnicity, establishing reliable reference standards for these values requires analysis of arterial blood at different elevations and locations. Our objective was to measure the arterial blood gases of healthy young volunteers in Huamachuco, Peru, at 3,164 m above sea level. This is likely the first study of arterial blood gas analysis of healthy Northern Peruvians living at high altitude. Methods: Healthy residents of Huamachuco were recruited for this cross-sectional convenience sample study and arterial blood was drawn by standard procedures. People with obesity, diabetes, high levels of physical activity and a history of using selected substances were excluded. The samples were analyzed on-site in less than 15 minutes using a Stat Profile Prime CCS analyzer (Nova Biomedical). Results: Data from 46 participants (17 male, 29 female) were included in the study. The median values for arterial blood pH, oxygen, carbon dioxide, ionized calcium, glucose, lactate, hematocrit, oxygen saturation, and bicarbonate were 7.42, 9.3 kPa (70 mmHg), 4.5 kPa (33.5 mmHg), 1.04 mM, 5.19 mM, 1.8 mM, 50 %, 94 %, and 21.6 mM, respectively. We also found a lower prevalence of diabetes among highlanders compared to the Peruvian population. Conclusions: The results determined here were comparable to other results determined at different altitudes in the Americas, although arterial blood oxygen was slightly higher than predicted. These results indicate that Northern Peruvians have an Andean-style adaptation to high altitude.

Effect of cerebral oxygen saturation monitoring in patients undergoing superficial temporal anterior-middle cerebral artery anastomosis for ischemic Moyamoya disease: a prospective cohort study.

Regional cerebral oxygen saturation (rSO2) is linked with blood pressure. This study evaluated the influence of perioperative rSO2 monitoring on the prognosis of ischemic Moyamoya disease (MMD) patients undergoing anastomosis surgery. In this prospective cohort, patients with unilateral ischemic MMD of Suzuki stage ≥3 were included. The decision of rSO2 was made by the clinician and the patient. The rSO2 group maintained intraoperative rSO2 levels through the modulation of blood pressure, inhaled oxygen concentration, carbon dioxide in arterial blood, and red blood cell transfusion. The non-rSO2 group used conventional anesthesia practices. Perioperative mean arterial pressure (MAP), rSO2 values, neurological complications, and postoperative results were assessed. A total of 75 eligible patients were categorized into a rSO2 monitoring group (n = 30) and a non-rSO2 monitoring group (n = 45). For the rSO2 group, the preoperative rSO2 was significantly lower on the affected side (P < 0.05). After anastomosis, this value notably increased (P = 0.01). A moderate relationship was observed between perioperative rSO2 and MAP before, during, and after surgery, with correlation coefficients (r) of 0.536, 0.502, and 0.592 (P < 0.05). Post-surgery MAP levels differed between the groups, with the rSO2 group showing decreased levels compared to pre-surgery and the non-rOS2 group displaying elevated levels. Notably, the rSO2 group reported shorter hospitalizations and decreased neurological complications. Patients with a hypertension history found postoperative MAP influencing hospital stay duration. Perioperative rSO2 surveillance enhanced cerebral perfusion and minimized postoperative complications in ischemic MMD patients. Thus, rSO2 monitoring is advocated for MMD patients undergoing vascular anastomosis.

Risk factors analysis of protein energy wasting in children with chronic kidney disease

Objective: To analyze the clinical characteristics and risk factors of protein energy wasting (PEW) in children with chronic kidney disease (CKD). Methods: Clinical data of 231 children with chronic kidney disease hospitalized in Beijing Children's Hospital affiliated to Capital Medical University from January 2018 to January 2023 were retrospectively analyzed to explore the incidence of PEW. According to the diagnostic criteria of CKDPEW, they were divided into a CKDPEW group and a non PEW group. The comparison between the groups was performed by independent-sample t test and Chi-squared test, and the risk factors were analyzed by multivariate Logistic regression. Results: Among the 231 children, there were 138 males and 93 females, with a visiting age of 9.9 (7.9, 16.0) years; 6 cases were in stage 1, 14 cases in stage 2, 51 cases in stage 3, 36 cases in stage 4, and 124 cases in stage 5. A total of 30 children (13.0%) with CKD PEW were diagnosed at the age of 7. 1 (3.8, 13.2) years, including 1 case in stage 1, 1 case in stage 2, 5 cases in stage 3, 5 cases in stage 4, and 18 cases in stage 5. There were a total of 201 cases (87.0%) in the non PEW group, diagnosed at the age of 11.8 (8.5, 12.2) years, including 5 cases in stage 1, 13 cases in stage 2, 46 cases in stage 3, 31 cases in stage 4, and 106 cases in stage 5. The Chi-squared test and t test showed that the systolic blood pressure, diastolic blood pressure, birth weight and carbon dioxide binding capacity of the CKD PEW group were lower than those of the non PEW group ((109±22) vs. (120±20) mmHg (1 mmHg=0.133 kPa), (72±19) vs. (79±16) mmHg, (2.9±0.5) vs. (3.2±0.6) kg, (17±4) vs. (19±4) mmol/L,t=2.85, 2.14, 0.67, 2.63, all P<0.05). Multivariate logistic regression analysis showed that carbon dioxide binding capacity and birth weight were independent protective factors of CKDPEW in children (OR=0.81 and 0.36, 95%CI=0.73-0.90 and 0.17-0.77, respectively; both P<0.01); the risk of PEW in CKD children decreased by 0.187 times for every 1 mmol/L increment in carbon dioxide binding capacity, and 0.638 times for every 1 kg increment in birth weight. Conclusions: The incidence of protein energy expenditure in children with chronic kidney disease is lower than that in the previous researches. PEW can appear in CKD 1-2 stage, and attention should be paid to it in the early stage of CKD in clinical practice. Low birth weight CKD children are susceptible to PEW, and actively correcting metabolic acidosis can reduce the risk of CKDPEW.

Intraoperative Blood Pressure and Carbon Dioxide Values during Aneurysmal Repair and the Outcomes after Aneurysmal Subarachnoid Hemorrhage.

Cerebral autoregulation impairment is a critical aspect of subarachnoid hemorrhage (SAH)-induced secondary brain injury and is also shown to be an independent predictor of delayed cerebral ischemia (DCI) and poor neurologic outcomes. Interestingly, intraoperative hemodynamic and ventilatory parameters were shown to influence patient outcomes after SAH. The aim of the current study was to evaluate the association of intraoperative hypotension and hypocapnia with the occurrence of angiographic vasospasm, DCI, and neurologic outcomes at discharge. Intraoperative data were collected for 390 patients with aneurysmal SAH who underwent general anesthesia for aneurysm clipping or coiling between January 2010 and May 2018. We measured the mean intraoperative blood pressure and end-tidal carbon dioxide (ETCO2), as well as the area under the curve (AUC) for the burden of hypotension: SBP below 100 or MBP below 65 and hypocapnia (ETCO2 < 30), during the intraoperative period. The outcome measures were angiographic vasospasm, DCI, and the neurologic outcomes at discharge as measured by the modified Rankin scale score (an mRS of 0-2 is a good outcome, and 3-6 is a poor outcome). Univariate and logistic regression analyses were performed to evaluate whether blood pressure (BP) and ETCO2 variables were independently associated with outcome measures. Out of 390 patients, 132 (34%) developed moderate-to-severe vasospasm, 114 (29%) developed DCI, and 46% (169) had good neurologic outcomes at discharge. None of the measured intraoperative BP and ETCO2 variables were associated with angiographic vasospasm, DCI, or poor neurologic outcomes. Our study did not identify an independent association between the degree of intraoperative hypotension or hypocapnia in relation to angiographic vasospasm, DCI, or the neurologic outcomes at discharge in SAH patients.

Assessing the impact of draught load pulling on welfare in equids.

About 112 million working equids are the source of income for 600 million people globally. Many equids are used for pulling loads (up to 15,000 kg per day) to transport goods. Most of them are associated with brick kilns, mining, and agriculture industries in developing countries. They may suffer from welfare issues such as overloading, being beaten, and being forced to work for long periods. These issues may occur due to a poor understanding of load-pulling equids. Understanding their capabilities and the elements that influence them is critical for efficient performance and welfare. The measurement of stride characteristics and gait kinematics can reveal loading adaptations and help identify loading limitations. It is known that both loading and fatigue change the locomotor patterns of load-pulling horses. Heart rate is a stress quantifying metric and an important representative of the speed of work and draught force. Heart rate variability is a regularly used statistic to quantify a physiological response to stresses, but it has never been used for load-pulling equids. Changes in blood lactate, nitrogen, oxygen, and carbon dioxide contents are reliable biochemical indicators of the effects of load pulling. Changes in plasma cortisol levels reflect the intensity of exercise and stress levels in horses while pulling a load. However, eye blink rate is a cheap, simple, and immediate indicator of acute equine stress, and we suggest it may be used to aid in load-pulling equine welfare assessment. However, further research is needed for a standardized and evidence-based draught load pulling capacity of working horses, mules, and donkeys.

Blood Gas Transport: Carriage of Oxygen and Carbon Dioxide in Blood.

The ways in which oxygen (O2) and carbon dioxide (CO2) are carried in the blood are well known and well understood, with a plethora of textbooks, both general and lung specific, all presenting the topic in a very similar manner. This first of two companion chapters similarly summarizes this information. First, carriage of gases by physical solution is described, followed by discussion of O2, carbon monoxide, and CO2 transport in that order. However, what available texts have not emphasized is why knowing how gases are carried in blood matters, and the second, companion, chapter specifically addresses that critical aspect of gas exchange physiology. In fact, each of the chapters in this volume describes physiological behavior that depends more or less directly on the dissociation curves of O2 and CO2.

Arterial blood analysis of healthy residents in Huamachuco, Peru (3,164 m): a cross-sectional study

Background: Given that arterial blood gas is affected by altitude and ethnicity, establishing reliable reference standards for these values requires analysis of arterial blood at different elevations and locations. Our objective was to measure the arterial blood gases of healthy young volunteers in Huamachuco, Peru, at 3,164 m above sea level. This is likely the first study of arterial blood gas analysis of healthy Northern Peruvians living at high altitude. Methods: Healthy residents of Huamachuco were recruited for this cross-sectional convenience sample study and arterial blood was drawn by standard procedures. People with obesity, diabetes, high levels of physical activity and a history of using selected substances were excluded. The samples were analyzed on-site in less than 15 minutes using a Stat Profile Prime CCS analyzer (Nova Biomedical). Results: Data from 46 participants (17 male, 29 female) were included in the study. The median values for arterial blood pH, oxygen, carbon dioxide, ionized calcium, glucose, lactate, hematocrit, oxygen saturation, and bicarbonate were 7.42, 9.3 kPa (70 mmHg), 4.5 kPa (33.5 mmHg), 1.04 mM, 5.19 mM, 1.8 mM, 50 %, 94 %, and 21.6 mM, respectively. We also found a lower prevalence of diabetes among highlanders compared to the Peruvian population. Conclusions: The results determined here were comparable to other results determined at different altitudes in the Americas, although arterial blood oxygen was slightly higher than predicted. These results indicate that Northern Peruvians have an Andean-style adaptation to high altitude.

Cardiorespiratory Effects and Desflurane Requirement in Dogs Undergoing Ovariectomy after Administration Maropitant or Methadone.

General anesthesia for ovariectomy in dogs is based on a balanced anesthesia protocol such as using analgesics along with an inhalant agent. While opioids such as fentanyl and methadone are commonly used for their analgesic potency, other drugs can also have analgesic effects. Maropitant, an antiemetic for dogs and cats, has also been shown to exert analgesic effects, especially on visceral pain. The aim of this study was to compare the cardiorespiratory effects and analgesic properties of maropitant and methadone combined with desflurane in dogs undergoing ovariectomy. Two groups of 20 healthy mixed-breeds bitches undergoing elective ovariectomy received intravenous either maropitant at antiemetic dose of 1 mg kg-1 or methadone at the dose of 0.3 mg kg-1. Cardiorespiratory variables were collected before premedication, 10 min after sedation and during surgery. Recovery quality and postoperative pain were evaluated 15, 30, 60, 120, 240 and 360 min postoperatively. Results showed that maropitant produced analgesia and reduced the requirement of desflurane in amounts similar to those determined by methadone (5.39 ± 0.20% and 4.91 ± 0.26%, respectively) without significant difference, while maintaining heart rate, arterial blood pressure, respiratory rate and carbon dioxide end-tidal partial pressure even at a more satisfactory level. Therefore, maropitant may be recommended as an analgesic drug for abdominal surgery not only in healthy dogs but also in those with reduced cardiorespiratory compensatory capacities or at risk of hypotension, especially when combined with a sedative such as dexmedetomidine.