Blood Gas Monitoring Research Articles

Respiratory Dysfunction and Abnormal Hypoxic Ventilatory Response in Mild to Moderate Parkinson's Disease.

Respiratory dysfunction is an important contributor to morbidity and mortality in advanced Parkinson's disease (PD), but it is unclear what parameters are sensitive to diagnose and monitor respiratory dysfunction across disease phases. We aimed to characterize respiratory dysfunction in mild to moderate PD. In 20 individuals without cardiopulmonary comorbidity, pulmonary and inspiratory muscle function testing were performed ON-medication. Subsequently, the acute ventilatory response to hypoxia (HVR) was assessed by gradually decreasing FIO2 from 0.209 (room air) to 0.127, which was compared to eight age- and sex-matched healthy controls under arterial blood gas monitoring. Lastly, on different days, the same 20 individuals with PD underwent six blinded exposures to 45-min normobaric hypoxia at FiO2 0.163 and 0.127 or placebo OFF-medication to assess breathing responses. At rest, individuals with greatest PD severity had a lower tidal volume (pairwise comparisons: 0.59 vs. 0.74, P = 0.038-0.050) and tended to have a higher breathing frequency (17.7 vs. 14.4, P = 0.076), despite normal pulmonary function. A 45-min exposure to hypoxia induced a significantly lower acute HVR in individuals with PD compared to controls (-0.0489 vs. 0.133 L.min/%, P = 0.0038). Acute HVR was reduced regardless of disease severity. Subacute HVR in individuals with milder disease tended to be higher compared to those with more advanced disease (P = 0.079). Respiratory dysfunction is present in individuals with PD, including those with relatively mild disease severity, and is characterized by altered breathing patterns at rest, as well as a lower HVR, despite normal pulmonary and inspiratory muscle function testing.

Predictive value of microcirculation for pediatric extracorporeal membrane oxygenation weaning test: Amonocentric prospective observational study.

Extracorporeal membrane oxygenation (ECMO) is widely used for children treated for refractory respiratory failures or refractory cardiogenic shock. Its duration depends on organ functions recovery. Weaning is decided using macro-circulatory tools, but microcirculation is not well evaluated. Sidestream dark-field video imaging is used to assess the perfusion of the sublingual microvascular vessels. The aim of this study was to assess the predictive value of microcirculatory indices in ECMO weaning. This prospective monocentric study examined pediatric patients at Trousseau Hospital between March 2017 and December 2020. The study included all patients from 35 weeks of gestational age to 18 years old who were treated with ECMO. Children were divided into two groups: one with stability after weaning and the other with instability after weaning. We collected clinical and biological data, ventilation parameters, extracorporeal membrane oxygenation parameters, and drugs used at admission and after the weaning test. Microcirculations videos were taken after weaning trials with echocardiography and blood gas monitoring. The study included 30 patients with a median age of 29 days (range: 1-770 days) at admission, including 18 patients who received venoarterial ECMO (60%). There were 19 children in the stability group and 11 in the instability group. Macrocirculatory and microcirculatory indices showed no differences between groups. The microvascular flow index was subnormal in both groups (2.3 (1.8-2.4) and 2.3 (2.3-2.6), respectively; p = 0.24). The microvascular indices were similar between cases of venovenous and venoarterial ECMO and between age groups. Microcirculation monitoring at the weaning phase did not predict the failure of ECMO weaning.

High velocity nasal insufflation versus non-invasive ventilation in acute respiratory failure: a comparative study

Background In order to treat respiratory failure, thermo-humidified nasal high flow oxygen (NHFO) therapy is being used more and more. In several clinical scenarios, NHFO has recently gained popularity as alternative noninvasive respiratory ventilation. Aim The aim is to assess the role of high velocity nasal insufflation (HVNI) versus noninvasive ventilation (NIV) in acute respiratory failure. Patients and methods This is a prospective randomized clinical study conducted on 60 patients admitted to the Chest Department at Menoufia University Hospital with acute respiratory failure. Patients were randomized to receive either noninvasive positive pressure ventilation using an oronasal mask or high-velocity nasal insufflation (initial flow was at 30-40 l/min; temperature was adjusted to 37°C; fraction of inspired oxygen 1.0) with clinical monitoring and arterial blood gas (ABG) monitoring after 2, 6, 12, and 24 h. Results The therapeutic impact of both, HVNI and NIV, on pressure of arterial carbon dioxide (PaCO2), hydrogen ion concentration, arterial oxygen saturation and pressure of arterial oxygen (PaO2) over time was almost similar. There was an improvement in dyspnea and a decrease in respiratory rate over time when compared with baseline results in both groups. There was no statistical difference between both groups. The failure rate in type I respiratory failure (RF) was 33.3% in the HVNI group and 28.6% in the NIV group (P-value 0.7). The failure rate in type II RF was 41.7% in the HVNI group and 25% in the NIV group (P-value 0.3). HVNI was more comfortable for patients and provided better communication and oral intake. Conclusion This study demonstrates that the HVNI was comparable to the NIV in the management of hypoxemic respiratory failure and could be used as a noninvasive method of ventilation alternative to the BiPAP in hypercapnic RF, with more comfortability and better communication in the HVNI group.

Challenges Encountered during Anaesthetic Management of a Patient with Congenital Methaemoglobinemia Posted for Laproscopic Inguinal Hernia Repair: A Case Report

Methaemoglobinemia is a rarely encountered haematological condition that can be congenital or acquired. Methaemoglobin is an abnormal type of haemoglobin that is oxidised and incapable of delivering oxygen to tissues. This can lead to cyanosis, hypoxia, acidosis, arrhythmias, and more, depending on the methaemoglobin concentration, and can be fatal. A thorough understanding of the disease process is essential to develop a suitable anaesthesia plan and prevent complications. Ensuring adequate tissue oxygenation, assessing oxygenation using appropriate monitoring tools, and avoiding trigger agents are the cornerstones of anaesthetic management. A co-oximeter is the gold standard for monitoring, as it detects and quantifies methaemoglobin levels. Methylene blue acts as an antidote, functioning as an oxidising agent that converts itself to leukomethylene blue, which reduces methaemoglobin back to haemoglobin. In the present case of a 60-year-old male, the authors present the anaesthetic management and challenges in a diagnosed case of congenital methaemoglobinemia undergoing laparoscopic inguinal hernia repair surgery. Methylene blue was administered prophylactically preoperatively. An arterial line was established before anaesthesia induction for close haemodynamic monitoring and quick blood gas and oxyhaemoglobin sampling, as a co-oximeter was not available. Adequate oxygenation during induction and emergence was ensured to prevent hypoxia, given the lower amount of normal haemoglobin in these patients. All potential trigger agents, such as nitrous oxide, local anaesthetics, nitrates, and metoclopramide, were avoided. The patient had an uneventful intraoperative and postoperative course and was discharged after one day.

Literature Review : Perbandingan Nilai PetCO2 dan PaCO2 Pada Pasien Kritis Terpasang Ventilasi Mekanik

Monitoring carbon dioxide in patients on mechanical ventilation is crucial for critical care nurses. Monitoring the value of arterial carbon dioxide pressure involves invasive arterial blood gas analysis. Monitoring end-tidal carbon dioxide pressure using capnography is a non-invasive method. This study aims to compare end-tidal carbon dioxide values with arterial carbon dioxide pressure in mechanically ventilated patients. The research design is a literature review. Searches were conducted through Scopus, ScienceDirect, ProQuest, and PubMed from 2018 to 2023. The Preferred Reporting Items for Systematic Review and Meta-Analyses flowchart method was used to select articles. The Critical Appraisal Skills Programme was used to assess article quality. Out of 79 articles, nine articles met the criteria. The procedures for collecting end-tidal carbon dioxide pressure and arterial carbon dioxide pressure data varied in terms of instrument types used and the subjects studied. There was no significant difference in carbon dioxide values between the end-tidal carbon dioxide and arterial carbon dioxide pressure methods. The agreement in comparing carbon dioxide values was acceptable. Measuring end-tidal carbon dioxide pressure has the potential to monitor mechanically ventilated patients, reducing the need for invasive monitoring, high costs, and repetitive arterial blood gas analysis.

Modeling and Evaluation of a Rate-Based Transcutaneous Blood Gas Monitor.

Current methods for transcutaneous blood gas monitoring (TBM) - a common health monitoring method in neonatal care - comes with a suite of challenges like limited attachment opportunities, and risks of infections from burning and tearing of the skin, which limits its use. This study presents a novel system and method for rate-based transcutaneous CO2 measurements with a soft, unheated skin-interface that can address many of these problems. Additionally, a theoretical model for the gas transport from the blood to the system's sensor is derived. By simulating CO2 advection and diffusion through the cutaneous microvasculature and epidermis to the system's skin interface, the effect of a wide range of physiological properties on the measurement has been modeled. Following these simulations, a theoretical model for the relationship between the measured CO2 concentration and that in the blood was derived and compared to empirical data. Applying the model on measured blood gas levels, even when the theory was based solely on the simulations, produced blood CO2 concentrations within ∼35% of empirical measurements from a state-of-the-art device. Further calibration of the framework, also using the empirical data, yielded an output with a Pearson correlation of 0.84 between the two methods. Compared to the state-of-the-art device the proposed system measured the partial CO2 pressure in the blood with an average deviation of 0.04 kPa and 1.97σ of ±1.1 kPa. However, the model indicated that this performance could be hampered by different skin properties. Given its soft and gentle skin interface and lack of heating, the proposed system could significantly decrease health risks like, burns, tears, and pain, currently associated with TBM on premature neonates.

Anesthetic management of a case of pulmonary alveolar proteinosis for whole lung lavage

Abstract Pulmonary Alveolar Proteinosis (PAP) is a rare disease of the lungs characterized by deposition of lipo-proteinaceous material in the alveoli. This leads to reduced lung compliance and V/Q mismatch, causing respiratory failure. Patients with PAP may be posted for Whole Lung Lavage (WLL) under anesthesia, which is a challenging case for anesthetists. Preexisting respiratory failure is complicated by requirement of single lung ventilation with the help of double lumen tube during the procedure. Intraoperative ventilation is difficult and is managed with blood gas and airway pressure monitoring. Some degree of hypoxemia and hypercapnia may have to be tolerated. Large volumes of fluid are instilled into the lung which may cause hypothermia, hypervolemia, and electrolyte disturbances. These patients frequently require elective ventilation and intensive care admission in the postoperative period. We report the case of a young woman with PAP, posted for unilateral WLL under anesthesia. We wish to highlight the possible challenges posed by this case and how to conduct a safe anesthesia for this patient.

Critical Care Length of Stay and Support Requirements for Patients Postpancreas Transplant.

Introduction: Pancreas transplant is one of the UK's less commonly done solid abdominal organ transplants. The transplant is reputed for its high-risk postsurgical complications due to multiple patients, procedures, and immunological factors. For this reason, patients are habitually admitted to the intensive care unit for postlaparotomy care, physiological support, and graft function monitoring during their immediate postoperative course. Project Aim: This program evaluation analyzed the trend in critical care length of stay and organ support requirements for patients following whole pancreas transplantation. The aim was to use these baseline data as performance metrics to enable a safer transition and Plan-Do-Study-Act (PDSA) cycles in improving the delivery of enhanced recovery service. Design: A retrospective chart review was performed using records from Phillips IntelliSpace Critical Care and Anaesthesia system to evaluate the institutional outcomes of patients < 18 years admitted to intensive care following pancreas transplantation between January 1, 2018, and December 31, 2021. Islet-cell transplant recipients were excluded as there is a different postoperative recovery. Results: The data suggested that although patients require a higher level of observations, blood pressure management, blood gas, and glucose monitoring during their first week of transplant, these patients did not routinely require the full range of critical care support. Conclusion: The present evaluation reported the organ support requirements for these transplant recipients. The results will generate further interest in enhanced recovery and service evaluation projects to streamline the postoperative care of these patients from the operating theatre back to the transplant wards.

Systemic Arterial Oxygen Levels Differentiate Pre- and Post-capillary Predominant Hemodynamic Abnormalities During Exercise in Undifferentiated Dyspnea on Exertion

Whether systemic oxygen levels (SaO2) during exercise can provide a window into invasively derived exercise hemodynamic profiles in patients with undifferentiated dyspnea on exertion is unknown. We performed cardiopulmonary exercise testing with invasive hemodynamic monitoring and arterial blood gas sampling in individuals referred for dyspnea on exertion. Receiver operator analysis was performed to distinguish heart failure with preserved ejection fraction from pulmonary arterial hypertension. Among 253 patients (mean ± SD, age 63 ± 14 years, 55% female, arterial O2 [PaO2] 87 ± 14 mmHg, SaO2 96% ± 4%, resting pulmonary capillary wedge pressure [PCWP] 18 ± 4mmHg, and pulmonary vascular resistance [PVR] 2.7 ± 1.2 Wood units), there was no exercise PCWP threshold, measured up to 49 mmHg, above which hypoxemia was consistently observed. Exercise PaO2 was not correlated with exercise PCWP (rho = 0.04; P = 0.51) but did relate to exercise PVR (rho = -0.46; P < 0.001). Exercise PaO2 and SaO2 levels distinguished left-heart-predominant dysfunction from pulmonary-vascular-predominant dysfunction with an area under the curve of 0.89 and 0.89, respectively. Systemic O2 levels during exercise distinguish relative pre- and post-capillary pulmonary hemodynamic abnormalities in patients with undifferentiated dyspnea. Hypoxemia during upright exercise should not be attributed to isolated elevation in left heart filling pressures and should prompt consideration of pulmonary vascular dysfunction.

PDMS-polyimide transcutaneous blood gas collector with self-folding out-of-plane heater elements

This paper introduces and evaluates a novel, highly scalable fabrication technique for folding flexible printed circuit board (PCB) features into polydimethylsiloxane (PDMS). The technique is then used to create fast and effective skin-heaters in a prototype gas collector for transcutaneous blood gas monitoring (TBM), a well-established technique to non-invasively measure the amount of CO2 and O2 in a patient’s blood. Previous studies have shown that TBM can be made safer by heating the patient’s skin with short pulses rather than continuously. Hence, the effects of incorporating a resistive heater with folded heating elements into a PDMS gas collector was investigated and compared to a heater with surface mounted heating elements. The results show that the fabrication technique provides consistent, controllable folding angles using only the surface and viscous forces of the flexible PCB and PDMS. With the investigated design- and material parameters a maximum folding angle of 30° was achieved, resulting in a 2000% increase in initial surface heating compared to an un-folded reference. For the intended application, this corresponds to reducing the time needed to heat the skin of a patient to less than half. The presented fabrication technique is, however, not limited to the application investigated in this paper, but rather offers the possibility to quickly and automatically fold complex structures and circuits into the bulk of the PDMS without introducing any time overhead as the number of features and folds grow.

Improving the Clinical Interpretation of Transcutaneous Carbon Dioxide and Oxygen Measurements in the Neonatal Intensive Care Unit

Introduction: Transcutaneous blood gas monitoring allows for continuous non-invasive evaluation of carbon dioxide and oxygen levels. Its use is limited as its accuracy is dependent on several factors. We aimed to identify the most influential factors to increase usability and aid in the interpretation of transcutaneous blood gas monitoring. Methods: In this retrospective cohort study, transcutaneous blood gas measurements were paired to arterial blood gas withdrawals in neonates admitted to the neonatal intensive care unit. The effects of patient-related, microcirculatory, macrocirculatory, respiratory, and sensor-related factors on the difference between transcutaneously and arterially measured carbon dioxide and oxygen values (ΔPCO₂ and ΔPO₂) were evaluated using marginal models. Results: A total of 1,578 measurement pairs from 204 infants with a median [interquartile range] gestational age of 27³/₇ [26¹/₇–31³/₇] weeks were included. ΔPCO₂ was significantly associated with the postnatal age, arterial systolic blood pressure, body temperature, arterial partial pressure of oxygen (PaO₂), and sensor temperature. ΔPO₂ was, with the exception of PaO₂, additionally associated with gestational age, birth weight Z-score, heating power, arterial partial pressure of carbon dioxide, and interactions between sepsis and body temperature and sepsis and the fraction of inspired oxygen. Conclusion: The reliability of transcutaneous blood gas measurements is affected by several clinical factors. Caution is recommended when interpreting transcutaneous blood gas values with an increasing postnatal age due to skin maturation, lower arterial systolic blood pressures, and for transcutaneously measured oxygen values in the case of critical illness.

Kedilerde Butorfanol, Medetomidin ve Ketamin Kombinasyon Anestezisi ile Yapılan Ovaryohisterektomi Sırasında Kan Gazı Parametrelerindeki Değişikliklerin Değerlendirilmesi

The aim of this study was to determine the effect of anesthesia with a combination of butorphanol, medetomidine and ketamine on blood gas parameters during ovariohysterectomy in queens. Nineteen queens of different breeds, between 6 and 72 months of age, which were neutered, were used in the study. Before anesthesia, 1 mL of blood was taken from Vena cephalica antebrachi to a heparinized syringe and blood gas parameters were evaluated. Queens determined to be healthy as a result of clinical examination and laboratory analyzes were taken under general anesthesia for ovariohysterectomy. Butorphanol (0.01 mg/kg, IV) was administered for anesthesia induction, medetomidine (0.08 mL/kg, IV) was administered 5 minutes after following the induction and ketamine (5-7.5 mg/kg, IV) was administered intravenously 10 minutes later. At the 10th minute of ketamine administration, blood samples were taken from the queens again. Blood gas parameters such as pH, pCO2, pO2, sO2, Na, Ca, K, Cl, Glu, Lac, BE and HCO3 were evaluated in blood samples taken before and during anesthesia. It was determined that pH, pO2, sO2, BE and HCO3 levels were lower and pCO2 and lactate concentrations were higher in anesthesia-induced queens compared to pre-anesthesia. As a result, it was thought that monitoring blood gas parameters in queens undergoing ovariohysterectomy may be useful to prevent complications that may occur before and after the operation.

Вопросы ранней диагностики и своевременной коррекции дыхательных нарушений при боковом амиотрофическом склерозе (обзор литературы)

Amyotrophic lateral sclerosis (ALS) is a rare severe progressive neurodegenerative disease with upper and lower motor neuron lesions, manifested by weakness of somatic muscle tissue with disorder of vital functions and leading to early disability and fatal outcome of patients. Regardless of the disease form, patients with ALS experience breathing and swallowing disorders. Hypercapnic respiratory failure (HRF) most commonly develop in patients as a consequence of respiratory muscle weakness. Instrumental diagnostic methods are currently used along with the assessment of the HRF clinical picture in ALS. Pulse oximetry and spirometry are the basic means of assessing the respiratory system function. Cardio-respiratory monitoring and arterial blood gas test play an auxiliary role in the diagnosis. To correct respiratory disorders, respiratory support is used with the help of artificial ventilation devices connected through various masks (non-invasive) or through a tracheostomy (invasive). In recent years, it has been proven that early diagnosis and correction of respiratory disorders contribute to prolonging the life of patients with ALS and improving its quality. The review presents the main development mechanisms of respiratory disorders in ALS, clinical and instrumental methods of their diagnosis, methods of correction, as well as criteria for the start of respiratory support. KEYWORDS: amyotrophic lateral sclerosis, respiratory disorders, lung ventilation, pulmonary support, neurodegeneration, NIV, ALV. FOR CITATION: Ermilov E.A., Isaeva N.V. Issues concerning early diagnosis and timely correction of respiratory disorders in amyotrophic lateral sclerosis (literature review). Russian Medical Inquiry. 2023;7(8). (in Russ.). DOI: 10.32364/2587-6821-2023-7-8-4.

Comparison of Antera 3D® and TcPO2 for Evaluation of Blood Flow in Skin.

There is a need for quick skin blood flow tests that can be performed in the wound healing field. Antera 3D® is a compact scanner using multispectral imaging. It can perform quick assessment of skin conditions. The purpose of the present study was to investigate the ability of the Antera 3D® to assess skin blood flow in comparison with transcutaneous partial pressure of oxygen (TcPO2) measurements. This study was conducted on 13 patients with a history of lower extremity ulcers. Measurements of hemoglobin average level (hereafter, Hb score) measured by Antera 3D® and TcPO2 measured by a transcutaneous blood gas monitor were obtained at the same sites on the dorsal foot and lower leg. Differences in Hb score and TcPO2 were analyzed by t-test for each measurement site and for the presence of peripheral arterial disease (PAD). The correlation between TcPO2 and Hb score was analyzed by Pearson's correlation coefficient. Twenty-four limbs were tested. Hb score was higher (P < 0.001) and TcPO2 was lower (P = 0.056) in the dorsal foot compared to the lower leg. In the dorsal foot, Hb score was higher (P = 0.023) and TcPO2 was lower (P = 0.046) in patients with PAD compared to those without PAD. A significant negative correlation (r = -0.68; 95% confidence interval -0.85 to -0.38, P < 0.001) between TcPO2 and Hb score was observed in the dorsal foot. The negative correlation between TcPO2 and Hb score may reflect compensatory peripheral vasodilation due to occlusion or stenosis of central arteries. This study showed that Hb score measured by Antera 3D® may be related to skin blood flow.

349: EVALUATING CONCORDANCE BETWEEN LAB HEMOGLOBIN/HEMATOCRIT AND POINT-OF-CARE TESTS IN PEDIATRIC ECMO

Introduction: Accuracy of point-of-care (POC) hemoglobin (Hgb) and hematocrit (Hct) testing in critically ill patients on extracorporeal membrane oxygenation (ECMO) support is unknown. Advantages of POC testing include immediate results and smaller blood volume, however inaccurate results can lead to repeat testing and could contribute to increased blood transfusion. The objectives of this study were to quantify agreement between lab-based and POC tests for Hgb and Hct in critically ill pediatric patients on ECMO. Methods: A single center retrospective study from January 1, 2013 to December 31, 2021. Lab and POC results were recorded if obtained within 5 minutes of each other. A single set of values was recorded per day, using the values closest to 4AM if multiple sets were obtained, and up to 10 days of an individual ECMO course were included. POC measures included in-line hematocrit monitor and bedside blood gas analyzer. Discordance was a priori defined as > 0.5g/dL (Hgb) or > 1.5% (Hct) discrepancy. Exclusion criteria were: > 18 years of age, cannulated at outside hospital, converted to other mechanical circulatory support, ECMO support during OR only, and subsequent ECMO courses during the study. Results: 136 patients were included with an average age of 2 months. 51% were female. 66% VA ECMO and 34% VV ECMO. Diagnoses included sepsis (8.1%), trauma (2.9%), cardiac s/p CPB (29%), cardiac non-CPB (15%), congenital diaphragmatic hernia (CDH) (12%), and non-CDH respiratory (31%). The average ECMO duration included in analyses was 7 days. 279 values compared lab-based to in-line, of which 27% were discordant for Hgb and 24% for Hct. 59 values compared lab-based to blood gas analyzer, of which 32% were discordant for Hgb and 36% for Hct. All discordant results had a lower POC value. Conclusions: Lab-based hemoglobin and hematocrit values compared to both blood gas analyzer and in-line hematocrit monitor were often discordant. In all cases, POC measures were lower, raising concerns that use of POC to guide transfusions could increase transfusion burden. Further study is needed to evaluate factors predictive of discordance and to determine effects of POC hemoglobin/hematocrit measures on transfusion burden in pediatric ECMO patients.

Association between preoperative hypokalemia and postoperative complications in elderly patients: a retrospective study

BackgroundHypokalemia is a common form of electrolyte disorder, which has a higher incidence in hospitalized patients and is closely related to perioperative complications and prognosis. Due to decreased skeletal muscle mass which causes total body potassium reduction, and increased comorbidities, the elderly are more susceptible to hypokalemia.ObjectiveTo investigate preoperative hypokalemia in elderly patients and its effect on postoperative complications.MethodsData were retrospectively collected from the elderly patients who underwent elective surgery from April 2018 to March 2019 and had preoperative blood gas data available. Patients, with age 60 to 100 years, were divided into hypokalemia group (potassium level < 3.5 mmol/L) and normokalemia group (potassium level between 3.5 and 5.5 mmol/L) according to preoperative blood gas analysis. Hypokalemia can be divided into mild (potassium level 3.0 to 3.5 mmol/L), moderate (potassium level 2.5 to 3.0 mmol/L) and severe (potassium level < 2.5 mmol/L), respectively. The risk factors of preoperative hypokalemia and its impact on postoperative complications and prognosis were primary outcomes. Secondary outcomes included postanesthesia care unit (PACU) stay time and hospital length of stay (LOS).ResultsOf 987 participants, 436 (44.17%) developed preoperative hypokalemia, among them 357 (81.88%) mild, 87 (16.74%) moderate and 6 (1.38%) severe. Multivariate logistic regression showed that female gender (OR, 1.851; 95% CI, 1.415–2.421), pre-existing hypokalemia at admission (OR, 4.498; 95% CI, 2.506–8.071), and oral laxative twice or more (OR, 1.823; 95% CI, 1.266–2.624) are risk factors of preoperative hypokalemia. Gynecological and biliopancreatic surgery were more common in hypokalemia group than normokalemia group (P < 0.001, P < 0.05). There was no significant difference in postoperative complications, PACU stay time, LOS, and 30-day mortality between the two groups (all P > 0.05).ConclusionsFemale gender, pre-existing hypokalemia at admission, and oral laxative twice or more are independent risk factors for preoperative hypokalemia in elderly patients. However, postoperative complications and 30-day mortality were not increased, which may be related to monitoring blood gas analysis and prompt correction of potassium levels during surgery.

Application value of monitoring of percutaneous partial pressure of carbon dioxide/oxygen for patients in ICU after general anesthesia

For patients in ICU under mechanical ventilation, monitoring of percutaneous partial pressure of CO2 and O2 after general anesthesia is crucial as excessive or insufficient ventilation may prove to be fatal. However, the correlation between percutaneous monitoring and arterial blood gas analysis still remains unclear. Here, we studied the application value of monitoring of PtcCO2/PtcO2 for patients in ICU after general anesthesia for better management of patients in ICU on ventilation. A total of 195 eligible patients were selected. After transfer, when PtcCO2 and PtcO2 were stable (10-15 min), they were recorded as transfer-in values. Partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), lactate, PtcO2 and PtcCO2 were recorded. Vital signs and hemodynamics data were also recorded. There were significant positive correlations between PtcCO2 and PtcO2 (r = 0.876), and between PtcO2 and PaCO2 (r = 0.817) (P &lt;0.01). PaO2 was higher than PtcO2 (P &lt;0.01). There were significant positive correlations between PtcCO2/PtcO2 and PaCO2/PaO2 at different time points (T0: upon transfer-in; T1: before extubation; T2: upon transfer-out, P &lt;0.01). At different oxygen inhalation concentrations (21, 40 and 50%), PtcCO2 and PtcO2 were all well linearly correlated. The overall PtcO2/PaO2 was (0.75±0.12). When FIO2 values were 21, 40 and 50%, PtcO2/PaO2 values were similar (P &gt;0.05). PtcCO2 and PtcO2 or PtcO2 and PaCO2 are significantly positively correlated, without significant differences between different time periods or oxygen concentrations. PtcCO2 and PtcO2 can predict the changes of PtcO2 and PaCO2, which is of great significance to the early observation of oxygenation changes, adjustment of ventilator parameters and improvement of prognosis. PtcCO2/PaO2 values are similar at different oxygen concentrations, as an eligible index for the postoperative evaluation of tissue perfusion status and hemodynamic level.

Transcutaneous blood gas monitoring and tissue perfusion during common femoral thromboendarterectomy

Background Improving tissue perfusion can improve clinical outcomes in surgical patients, where monitoring may aid clinicians in detecting adverse conditions and guide interventions. Transcutaneous monitoring (TCM) of oxygen (tcpO2) and carbon dioxide (tcpCO2) is a well-proven technology and could potentially serve as a measure of local circulation, perfusion and metabolism, but the clinical use is not thoroughly explored. The purpose of this proof-of-concept study was to investigate whether TCM of blood gasses could detect changes in perfusion during major vascular surgery. Methods Ten patients with peripheral arterial disease scheduled for lower limb major arterial revascularization under general anaesthesia were consecutively included. TcpO2 and tcpCO2 were continuously recorded from anaesthesia induction until skin closure with a TCM monitor placed on both legs and the thorax. Peripheral oxygen saturation was kept ≥94% and mean arterial blood pressure ≥65 mmHg. The primary outcomes were changes in tcpO2 and tcpCO2 related to arterial clamping and declamping during the procedure and analyzed by paired statistics. Results Femoral artery clamping resulted in a significant decrease in tcpO2 (−2.1 kPa, IQR-4.2; −0.8), p=.017)), followed by a significant increase in response to arterial declamping (5.5 kPa, IQR 0–7.3), p=.017)). Arterial clamping resulted in a statistically significant increase in tcpCO2 (0.9 kPa, IQR 0.3–5.4), p=.008)) and a significant decrease following declamping (−0.7 kPa, IQR −2.6; −0.2), p=.011)). Conclusion Transcutaneous monitoring of oxygen and carbon dioxide is a feasible method for detection of extreme changes in tissue perfusion during arterial clamping and declamping, and its use for improving patient outcomes should be explored. Clinical Trials identifier: NCT04040478. Registered on July 31, 2019.

Procedural and Methodological Quality in Preclinical Stroke Research-A Cohort Analysis of the Rat MCAO Model Comparing Periods Before and After the Publication of STAIR/ARRIVE.

The translation of preclinical stroke research into successful human clinical trials remains a challenging task. The first Stroke Therapy Academic Industry Roundtable (STAIR) recommendations for preclinical research and several other guidelines were published to address these challenges. Most guidelines recommend the use of physiological monitoring to detect the occurrence of undesired pathologies such as subarachnoid hemorrhage and to limit the variability of the infarct volume and–therefore-homogenize the experimental result for complete reporting particularly with respect to transparency and methodological rigor. From the years 2009 and 2019, 100 published articles each using a rat stroke model were analyzed to quantify parameters related to anesthesia, physiological monitoring, stroke model type, ischemia verification, and overall study quality over time. No significant difference in the frequency of cerebral blood flow (CBF) measurements over time (28/34% for 2009/2019) was found. Notably, significantly fewer studies reported temperature, blood pressure, and blood gas monitoring data in 2019 compared to 2009. On the other hand, an increase in general study quality parameters (e.g., randomization, reporting of approval) was seen. In conclusion, the frequency of periinterventional monitoring has decreased over time. Some general methodological quality aspects, however, partially have increased. CBF measurement–the gold standard for ischemia verification-was applied rarely. Despite the growing recognition of current guidelines such as STAIR and ARRIVE (both widely approved in 2019) reporting, methods and procedures mostly do not follow these guidelines. These deficits may contribute to the translational failure of preclinical stroke research in search for neuroprotective therapies.

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.