The value of umbilical artery blood gas analysis in the rapid diagnosis of fetomaternal hemorrhage.

As a rare obstetric disease, fetomaternal hemorrhage (FMH) often causes severe fetal anemia, edema and even death, easily to be confused with severe neonatal asphyxia. Currently, there are several ways to detect or predict FMH, however, most of them are flawed and time-consuming, as well as unsuitable for rapid diagnosis and timely intervention of FMH. To explore the values of umbilical artery blood gas analysis in the rapid diagnosis of FMH, providing basis for rapid guidance of newborn rescue. Five cases of neonates with FMH from the First Affiliated Hospital of Army Military Medical University (Chongqing Southwest Hospital) from January 2013 to January 2016 were selected as the study group. Another 9 cases of severe asphyxia neonates were chosen into the control group. The difference in Apgar score and umbilical artery blood gas analysis between the 2 groups at birth was compared, and the treatments and clinical outcomes of the 2 groups were analyzed. The PH value of umbilical artery blood gas analysis in the study group was higher than that of the control group, but the difference was not statistically significant (P > .05). In the study group, cases with pH value < 7.0 accounted for 0%, whereas the cases with pH < 7.0 accounted for 66.67% in the control group, and the difference between the 2 groups was statistically significant (P < .05). Compared with the control group, the arterial oxygen partial pressure (PO2), the absolute value of (PCO2), lactic acid (lac) and alkali were not significantly different from those of the control group (P > .05), while the total hemoglobin (tHb) and hematocrit (Hct) were significantly lower than the control group (P < .0001). In the study group, tHb in the umbilical cord blood of 2 newborns with FMH death was significantly lower than 40 g/L. FMH should be highly suspected when there is an expression of severe asphyxia in neonates, indicated by significantly lower tHb levels in umbilical cord blood. It is helpful to improve the neonatal outcome by FMH neonatal resuscitation as soon as possible.

Utility of Skin Tone on Pulse Oximetry in Critically Ill Patients: A Prospective Cohort Study.

OBJECTIVE: Pulse oximetry, a ubiquitous vital sign in modern medicine, has inequitable accuracy that disproportionately affects minority Black and Hispanic patients, with associated increases in mortality, organ dysfunction, and oxygen therapy. Previous retrospective studies used self-reported race or ethnicity as a surrogate for skin tone which is believed to be the root cause of the disparity. Our objective was to determine the utility of skin tone in explaining pulse oximetry discrepancies. DESIGN: Prospective cohort study. SETTING: Patients were eligible if they had pulse oximetry recorded up to 5 minutes before arterial blood gas (ABG) measurements. Skin tone was measured using administered visual scales, reflectance colorimetry, and reflectance spectrophotometry. PARTICIPANTS: Admitted hospital patients at Duke University Hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sao2-Spo2 bias, variation of bias, and accuracy root mean square, comparing pulse oximetry, and ABG measurements. Linear mixed-effects models were fitted to estimate Sao2-Spo2 bias while accounting for clinical confounders.One hundred twenty-eight patients (57 Black, 56 White) with 521 ABG-pulse oximetry pairs were recruited. Skin tone data were prospectively collected using six measurement methods, generating eight measurements. The collected skin tone measurements were shown to yield differences among each other and overlap with self-reported racial groups, suggesting that skin tone could potentially provide information beyond self-reported race. Among the eight skin tone measurements in this study, and compared with self-reported race, the Monk Scale had the best relationship with differences in pulse oximetry bias (point estimate: -2.40%; 95% CI, -4.32% to -0.48%; p = 0.01) when comparing patients with lighter and dark skin tones. CONCLUSIONS: We found clinical performance differences in pulse oximetry, especially in darker skin tones. Additional studies are needed to determine the relative contributions of skin tone measures and other potential factors on pulse oximetry discrepancies.

Analysis of arterial blood gas values when discarding different volumes of blood samples in an arterial heparin blood collector during thoracoscopic surgery.

BACKGROUND: Arterial blood gas analysis (ABGA) plays a vital role in emergency and intensive care, which is affected by many factors, such as different instrumentation, temperature, and testing time. However, there are still no relevant reports on the difference in discarding different blood volumes on ABGA values. METHODS: We enrolled 54 patients who underwent thoracoscopic surgery and analysed differences in blood gas analysis results when different blood volumes were discarded from the front line of the arterial heparin blood collector. A paired t test was used to compare the results of the same patient with different volumes of blood discarded from the samples. The difference was corrected by Bonferroni correction. RESULTS: Our results demonstrated that the PaO2, PaCO2, and THbc were more stable in the 4th ml (PaO2 = 231.3600 ± 68.4878 mmHg, PaCO2 = 41.9232 ± 7.4490 mmHg) and 5th ml (PaO2 = 223.7600 ± 12.9895 mmHg, PaCO2 = 42.5679 ± 7.6410 mmHg) blood sample than in the 3rd ml (PaO2 = 234.1000 ± 99.7570 mmHg, PaCO2 = 40.6179 ± 7.2040 mmHg). CONCLUSION: It may be more appropriate to discard the first 3 ml of blood sample in the analysis of blood gas results without wasting blood samples.

Australian and New Zealand Society of Respiratory Science position statement for arterial blood gas sampling.

The assessment of gas exchange under varying ambient and metabolic conditions is an important and fundamental investigation of respiratory function. The gold standard is an arterial blood gas (ABG) sample; however, the procedure is not universally performed by medical scientists, is not standardised, and is typically taught by a subjective Halsted 'see one, do one' approach. The Australian and New Zealand Society of Respiratory Science recognised the need to create an ABG position statement that includes the required pre-requisite education, an evidence-based procedure and the minimum reporting and competency assessment requirements. This position statement aims to minimise patient discomfort, to improve puncture success rate and reduce the potential for sample handling and analysis error. Importantly, this position statement translates to all relevant health professionals, including medical officers, scientists, nursing staff and allied health.

The use of venous blood gas in assessing arterial acid-base and oxygenation status - an analysis of aggregated data from multiple studies evaluating the venous to arterial conversion (v-TAC) method.

BACKGROUND: Several methods exist to reduce the number of arterial blood gases (ABGs). One method, Roche v-TAC, has been evaluated in different patient groups. This paper aggregates data from these studies, in different patient categories using common analysis criteria. RESEARCH DESIGN AND METHODS: We included studies evaluating v-TAC based on paired arterial and peripheral venous blood samples. Bland-Altman analysis compared measured and calculated arterial values of pH, PCO2, and PO2. Subgroup analyses were performed for normal, chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and acute and chronic base deficits. RESULTS: 811 samples from 12 studies were included. Bias and limits of agreement for measured and calculated values: pH 0.001 (-0.029 to 0.031), PCO2 -0.08 (-0.65 to 0.49) kPa, and PO2 0.04 (-1.71 to 1.78) kPa, with similar values for all sub-group analyses. CONCLUSION: These data suggest that v-TAC analysis may have a role in replacing ABGs, avoiding arterial puncture. Substantial data exist in patients with chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and in patients with relatively normal acid-base status, with similar bias and precision across groups and across study data. Limited data exist for patients with acute and chronic base deficits.

Utilization of Multi-Parameter Blood Gas Analysis in Prehospital Emergency Medicine-A Scoping Review.

BACKGROUND: Prehospital blood gas analysis (BGA) is an evolving field that offers the potential for early identification and management of critically ill patients. However, the utility and accuracy of prehospital BGA are subjects of ongoing debate. OBJECTIVES: We aimed to provide a comprehensive summary of the current literature on prehospital BGA, including its indications, methods, and feasibility. METHODS: We performed a scoping review of prehospital BGA. A thorough search of the PubMed, Embase, and Web of Science databases was conducted to identify relevant studies focusing on prehospital BGA in adult patients. RESULTS: Fifteen studies met the inclusion criteria. Prehospital BGA was most frequently performed in patients in out-of-hospital cardiac arrest, followed by traumatic and nontraumatic cases. The parameters most commonly analyzed were pH, pCO2, pO2, and lactate. Various sampling methods, including arterial, venous, and intraosseous, were reported for prehospital BGA. While prehospital BGA shows promise in facilitating early identification of critical patients and guiding resuscitation efforts, logistical challenges are to be considered. The handling of preclinical BGA is described as feasible and useful in most of the included studies. CONCLUSION: Prehospital BGA holds significant potential for enhancing patient care in the prehospital setting, though technical challenges need to be considered. However, further research is required to establish optimal indications and demonstrate the benefits for prehospital BGA in specific clinical contexts.

Evaluation of the classifications of severity in acute respiratory distress syndrome in childhood by the Berlin Consensus and the Pediatric Acute Lung Injury Consensus Conference.

OBJECTIVE: To compare two methods for defining and classifying the severity of pediatric acute respiratory distress syndrome: the Berlin classification, which uses the relationship between the partial pressure of oxygen and the fraction of inspired oxygen, and the classification of the Pediatric Acute Lung Injury Consensus Conference, which uses the oxygenation index. METHODS: This was a prospective study of patients aged 0 - 18 years with a diagnosis of acute respiratory distress syndrome who were invasively mechanically ventilated and provided one to three arterial blood gas samples, totaling 140 valid measurements. These measures were evaluated for correlation using the Spearman test and agreement using the kappa coefficient between the two classifications, initially using the general population of the study and then subdividing it into patients with and without bronchospasm and those with and without the use of neuromuscular blockers. The effect of these two factors (bronchospasm and neuromuscular blocking agent) separately and together on both classifications was also assessed using two-way analysis of variance. RESULTS: In the general population, who were 54 patients aged 0 - 18 years a strong negative correlation was found by Spearman's test (ρ -0.91; p < 0.001), and strong agreement was found by the kappa coefficient (0.62; p < 0.001) in the comparison between Berlin and Pediatric Acute Lung Injury Consensus Conference. In the populations with and without bronchospasm and who did and did not use neuromuscular blockers, the correlation coefficients were similar to those of the general population, though among patients not using neuromuscular blockers, there was greater agreement between the classifications than for patients using neuromuscular blockers (kappa 0.67 versus 0.56, p < 0.001 for both). Neuromuscular blockers had a significant effect on the relationship between the partial pressure of oxygen and the fraction of inspired oxygen (analysis of variance; F: 12.9; p < 0.001) and the oxygenation index (analysis of variance; F: 8.3; p = 0.004). CONCLUSION: There was a strong correlation and agreement between the two classifications in the general population and in the subgroups studied. Use of neuromuscular blockers had a significant effect on the severity of acute respiratory distress syndrome.

Feasibility Analysis of ECG-Based pH Estimation for Asphyxia Detection in Neonates.

Birth asphyxia is a potential cause of death that is also associated with acute and chronic morbidities. The traditional and immediate approach for monitoring birth asphyxia (i.e., arterial blood gas analysis) is highly invasive and intermittent. Additionally, alternative noninvasive approaches such as pulse oximeters can be problematic, due to the possibility of false and erroneous measurements. Therefore, further research is needed to explore alternative noninvasive and accurate monitoring methods for asphyxiated neonates. This study aims to investigate the prominent ECG features based on pH estimation that could potentially be used to explore the noninvasive, accurate, and continuous monitoring of asphyxiated neonates. The dataset used contained 274 segments of ECG and pH values recorded simultaneously. After preprocessing the data, principal component analysis and the Pan-Tompkins algorithm were used for each segment to determine the most significant ECG cycle and to compute the ECG features. Descriptive statistics were performed to describe the main properties of the processed dataset. A Kruskal-Wallis nonparametric test was then used to analyze differences between the asphyxiated and non-asphyxiated groups. Finally, a Dunn-Sidák post hoc test was used for individual comparison among the mean ranks of all groups. The findings of this study showed that ECG features (T/QRS, T Amplitude, Tslope, Tslope/T, Tslope/|T|, HR, QT, and QTc) based on pH estimation differed significantly (p < 0.05) in asphyxiated neonates. All these key ECG features were also found to be significantly different between the two groups.

Evaluation of agreement between a noninvasive method for real-time measurement of critical blood values with a standard point-of-care device.

The purpose of this work was to investigate the degree of agreement between two distinct approaches for measuring a set of blood values and to compare comfort levels reported by participants when utilizing these two disparate measurement methods. Radial arterial blood was collected for the comparator analysis using the Abbott i-STAT® POCT device. In contrast, the non-invasive proprietary DBC methodology is used to calculate sodium, potassium, chloride, ionized calcium, total carbon dioxide, pH, bicarbonate, and oxygen saturation using four input parameters (temperature, hemoglobin, pO2, and pCO2). Agreement between the measurement for a set of blood values obtained using i-STAT and DBC methodology was compared using intraclass correlation coefficients, Passing and Bablok regression analyses, and Bland Altman plots. A p-value of <0.05 was considered statistically significant. A total of 37 participants were included in this study. The mean age of the participants was 42.4 ± 13 years, most were male (65%), predominantly Caucasian/White (75%), and of Hispanic ethnicity (40%). The Intraclass Correlation Coefficients (ICC) analyses indicated agreement levels ranging from poor to moderate between i-STAT and the DBC's algorithm for Hb, pCO2, HCO3, TCO2, and Na, and weak agreement for pO2, HSO2, pH, K, Ca, and Cl. The Passing and Bablok regression analyses demonstrated that values for Hb, pO2, pCO2, TCO2, Cl, and Na obtained from the i-STAT did not differ significantly from that of the DBC's algorithm suggesting good agreement. The values for Hb, K, and Na measured by the DBC algorithm were slightly higher than those obtained by the i-STAT, indicating some systematic differences between these two methods on Bland Altman Plots. The non-invasive DBC methodology was found to be reliable and robust for most of the measured blood values compared to invasive POCT i-STAT device in healthy participants. These findings need further validation in larger samples and among individuals afflicted with various medical conditions.

Changes in oxygen supply-demand balance during induction of general anesthesia: an exploratory study using remimazolam.

PURPOSE: This study was performed to evaluate the changes in oxygen supply-demand balance during induction of general anesthesia using an indirect calorimeter capable of measuring oxygen consumption (VO2) and carbon dioxide production (VCO2). METHODS: This study included patients scheduled for surgery in whom remimazolam was administered as a general anesthetic. VO2 and VCO2 were measured at different intervals: upon awakening (T1), 15 min after tracheal intubation (T2), and 1 h after T2 (T3). Oxygen delivery (DO2) was calculated simultaneously with these measurements. VO2 was ascertained using an indirect calorimeter and further calculated using vital signs, among other factors. DO2 was derived from cardiac output and arterial blood gas analysis performed with an arterial pressure-based cardiac output measurement system. RESULTS: VO2, VCO2, and DO2 decreased significantly from T1 to T2 and T3 [VO2/body surface area (BSA) (ml/min/m2): T1, 130 (122-146); T2, 107 (83-139); T3, 97 (93-121); p = 0.011], [VCO2/BSA (ml/min/m2): T1, 115 (105-129); T2, 90 (71-107); T3, 81 (69-101); p = 0.011], [DO2/BSA (ml/min/m2): T1, 467 (395-582); T2, 347 (286-392); T3, 382 (238-414); p = 0.0020]. Among the study subjects, a subset exhibited minimal reduction in VCO2. Although the respiratory frequency was titrated on the basis of end-tidal CO2 levels, there was no significant difference between the groups. CONCLUSION: General anesthetic induction with remimazolam decreased VO2, VCO2, and DO2.

Screening Strategies for Sleep-Disordered Breathing in Patients With Spinal Cord Injury in a Tertiary Care Rehabilitation Center.

BACKGROUND: Sleep-disordered breathing (SDB) is frequent in patients with spinal-cord injury (SCI). However, SDB is frequently underdiagnosed due to limited access to diagnostic testing and knowledge about the condition. Moreover, SDB heterogeneity (sleep apnea, obstructive sleep apnea or central sleep apnea and nocturnal alveolar hypoventilation) implies complex evaluation of both nocturnal respiratory effort and hypercapnia. The aim of this study was to compare different screening strategies for an SDB diagnosis in patients with SCI. METHODS: This was a retrospective analysis of data from subjects with SCI followed up in a tertiary-care rehabilitation center with a specialized sleep unit. Subjective (questionnaires) and objective data (polysomnography [PSG]), [Formula: see text] extracted from the PSG, morning blood gases, and nocturnal transcutaneous CO2 (PtcCO2 ) were collected and analyzed. A retrospective comparison of different strategies for SDB screening was carried out. Each strategy was compared (alone and in combination) with the standard of care for sleep apnea (PSG) and nocturnal alveolar hypoventilation (PtcCO2 ) diagnosis. The performance of the usual cutoff and visual analysis was studied. RESULTS: Among 190 subjects with SCI who underwent a full night's PSG, data were available for 104 questionnaires and 162 with oximetry. Nocturnal alveolar hypoventilation was screened by PtcCO2 and blood gases in 52 subjects with SCI. Questionnaires (the modified Screening for Obstructive Sleep Apnea in Tetraplegia and the Epworth Sleepiness Scale) had poor performance for identifying sleep apnea and did not identify nocturnal alveolar hypoventilation. [Formula: see text] (oxygen desaturation index score ≥ 13) and visual analysis of [Formula: see text] were good at identifying sleep apnea but insufficient to identify nocturnal alveolar hypoventilation. Diurnal blood gases were poor predictors of nocturnal alveolar hypoventilation. CONCLUSIONS: Questionnaires were of limited use in subjects with SCI, but the oxygen desaturation index derived from oximetry performed well for sleep apnea screening. Both diurnal blood gases and oximetry visual analysis were insufficient for nocturnal alveolar hypoventilation screening. PtcCO2 monitoring should be mandatory and ideally combined with PSG given the heterogeneity of SDB phenotypes and associated sleep comorbidities of patients with SCI.

The relation of lactate level and carbon dioxide pressure discrepancies between transcutaneous and arterial measurements.

Introduction: Partial carbondioxide pressure of the arterial blood (PaCO2) is used to evaluate alveolar ventilation. Transcutaneous carbon dioxide pressure (TcCO2) monitoring has been developed as a non-invasive (NIV) alternative to arterial blood gas analysis (ABG). Studies have shown that decreased tissue perfusion leads to increased carbondioxide (CO2). The use of transcutaneous capnometry may be unreliable in patients with perfusion abnormalities. In this study, we aimed to evaluate the relation between TcCO2-PaCO2 and lactate level which is recognized as a marker of hypoperfusion. Materials and Methods: In this prospective cohort study in critical care patients with hypercapnic respiratory failure (PaCO2 ≥45 mmHg) who received NIV between April 2019 and January 2020 in the intensive care unit were enrolled in the study. Patients' simultaneously measured TcCO2 and PaCO2 values of hypercapnic patients were recorded. Each paired measurement was categorized into two groups; normal lactate (<2 mmol/L) and increased lactate (≥2 mmol/L). Result: A total of 116 paired TcCO2 and PaCO2 measurements of 29 patients were recorded. Bland-Altman analysis showed the mean bias between the TcCO2 and PaCO2 and 95% limits of agreement (LOA) in all measurements (1.75 mmHg 95% LOA -3.67 to 7.17); in the normal lactate group (0.66 mmHg 95% LOA -1.71 to 3.03); and in the increased lactate group (5.17 mmHg 95% LOA -1.63 to 11.97). The analysis showed a correlation between lactate level and the difference between TcCO2 and PaCO2 (r= 0.79, p< 0.001) and a negative correlation between mean blood pressure and the difference between TcCO2 and PaCO2 (r= -0.54, p= 0.001). Multiple regression analysis results showed that lactate level was independently associated with increased differences between TcCO2 and PaCO2 (Beta= 0.875, p< 0.001). Conclusions: TcCO2 monitoring may not be reliable in patients with increased lactate levels. TcCO2 levels should be checked by ABG analysis in these patients.

Arterial blood gas analysis or venous blood gas analysis for adult hospitalised patients with respiratory presentations: a systematic review.

BACKGROUND: Identification of hypoxaemia and hypercapnia is essential for the diagnosis and treatment of acute respiratory failure. While arterial blood gas (ABG) analysis is standard for PO2 and PCO2 measurement, venous blood gas (VBG) analysis is increasingly used as an alternative. Previous systematic reviews established that VBG reporting of PO2 and PCO2 is less accurate, but the impacts on clinical management and patient outcomes are unknown. AIMS: This study aimed to systematically review available evidence of the clinical impacts of using ABGs or VBGs and examine the arteriovenous difference in blood gas parameters. METHODS: A comprehensive search of the MEDLINE, Embase and Cochrane Library databases since inception was conducted. Included studies were prospective or cross-sectional studies comparing peripheral ABG to peripheral VBG in adult non-critical care inpatients presenting with respiratory symptoms. RESULTS: Of 15 119 articles screened, 15 were included. No studies were found that examined clinical impacts resulting from using VBG compared to ABG. Included studies focused on the agreement between ABG and VBG measurements of pH, PO2, PCO2 and HCO3 -. Due to the heterogeneity of the included studies, qualitative evidence synthesis was performed. While the arteriovenous difference in pH and HCO3 - was generally predictable, the difference in PO2 and PCO2 was more significant and less predictable. CONCLUSIONS: Our study reinforces the notion that VBG is not comparable to ABG for physiological measurements. However, a key revelation from our research is the significant lack of data regarding the clinical implications of using VBG instead of ABG, a common scenario in clinical practice. This highlights a critical knowledge gap.

A portent of catastrophic carbon dioxide embolism in laparoscopic hepatectomy: A case report.

INTRODUCTION: Laparoscopic hepatectomy (LH) poses a high risk of carbon dioxide embolism due to extensive hepatic transection, long surgery duration, and dissection of the large hepatic veins or vena cava. PATIENT CONCERNS: A 65-year-old man was scheduled to undergo LH. Following intraperitoneal carbon dioxide (CO2) insufflation and hepatic portal occlusion, the patient developed severe hemodynamic collapse accompanied by a decrease in the pulse oxygen saturation (SpO2). DIAGNOSIS: Although a decrease in end-tidal carbon dioxide (ETCO2) was not observed, CO2 embolism was still suspected because of the symptoms. INTERVENTIONS AND OUTCOMES: The patient was successfully resuscitated after the immediate discontinuation of CO2 insufflation and inotrope administration. CO2 embolism must always be suspected during laparoscopic surgery whenever sudden hemodynamic collapse associated with decreased pulse oxygen saturation occurs, regardless of whether ETCO2 changes. Instant arterial blood gas analysis is imperative, and a significant difference between PaCO2 and ETCO2 is indicative of carbon dioxide embolism. CONCLUSION: Instant arterial blood gas analysis is imperative, and a significant difference between PaCO2 and ETCO2 is indicative of carbon dioxide embolism.

Comparison of Apgar scores and cord blood gas parameters in fetuses with isolated congenital heart disease and healthy controls.

OBJECTIVE: This retrospective study aimed to investigate how congenital heart disease (CHD) affects early neonatal outcomes by comparing Apgar scores and umbilical cord blood gas parameters between fetuses with structural cardiac anomalies and healthy controls. Additionally, within the CHD group, the study explored the relationship between these parameters and mortality within six months. METHODS: Data from 68 cases of prenatally diagnosed CHD were collected from electronic medical records, excluding cases with missing data or additional comorbidities. Only patients delivered by elective cesarean section, without any attempt at labor, were analyzed to avoid potential confounding factors. A control group of 147 healthy newborns was matched for delivery route, maternal age, and gestational week. Apgar scores at 1, 5, and 10 minutes, as well as umbilical cord blood pH, base deficit, and lactate levels, were recorded. RESULTS: Maternal age, gestational week at delivery, and birth weight were similar between the CHD and control groups. While Apgar score distribution was significantly lower at 1st, 5th, and 10th minutes in the CHD group, umbilical cord blood gas parameters did not show significant differences between groups. Within the CHD group, lower umbilical cord blood pH and larger base deficit were associated with mortality within six months. CONCLUSION: Newborns with CHD exhibit lower Apgar scores compared to healthy controls, suggesting potential early neonatal challenges. Furthermore, umbilical cord blood pH and base deficit may serve as predictors of mortality within six months in CHD cases. Prospective studies are warranted to validate these findings and integrate them into clinical practice, acknowledging the study's retrospective design and limitations.

[Blood gas analysis in the intensive cardiac care unit]. / La rapida lettura dell'emogasanalisi in unità di terapia intensiva cardiologica.

Arterial blood gas (ABG) analysis is a simple and quick test that can provide multiple respiratory and metabolic parameters. The interpretation of ABG analysis and acid-base disorders represents one of the most complex chapters of clinical medicine. In this brief review, the authors propose a rational approach that sequentially analyzes the information offered by the ABG to allow a rapid classification of the respiratory, metabolic or mixed disorder. The patient's history and clinical-instrumental assessment are the framework in which to insert the information derived from the ABG analysis in order to characterize the critical heart patient.

Monitoring lung recruitment.

PURPOSE OF REVIEW: This review explores lung recruitment monitoring, covering techniques, challenges, and future perspectives. RECENT FINDINGS: Various methodologies, including respiratory system mechanics evaluation, arterial bold gases (ABGs) analysis, lung imaging, and esophageal pressure (Pes) measurement are employed to assess lung recruitment. In support to ABGs analysis, the assessment of respiratory mechanics with hysteresis and recruitment-to-inflation ratio has the potential to evaluate lung recruitment and enhance mechanical ventilation setting. Lung imaging tools, such as computed tomography scanning, lung ultrasound, and electrical impedance tomography (EIT) confirm their utility in following lung recruitment with the advantage of radiation-free and repeatable application at the bedside for sonography and EIT. Pes enables the assessment of dorsal lung tendency to collapse through end-expiratory transpulmonary pressure. Despite their value, these methodologies may require an elevated expertise in their application and data interpretation. However, the information obtained by these methods may be conveyed to build machine learning and artificial intelligence algorithms aimed at improving the clinical decision-making process. SUMMARY: Monitoring lung recruitment is a crucial component of managing patients with severe lung conditions, within the framework of a personalized ventilatory strategy. Although challenges persist, emerging technologies offer promise for a personalized approach to care in the future.

Use of the combination of spirometry, arterial blood gas analysis and overnight oximetry to predict the outcomes of patients affected by motor neuron disease: The Milan-Torin respiratory score (Mi-To-RS).

BACKGROUND AND PURPOSE: The use of multiple tests, including spirometry, arterial blood gas (ABG) analysis and overnight oximetry (OvOx), is highly recommended to monitor the respiratory function of patients with motor neuron disease (MND). In this study, we propose a composite score to simplify the respiratory management of MND patients and better stratify their prognosis. MATERIALS AND METHODS: We screened the clinical charts of 471 non-ventilated MND patients referred to the Neuro-rehabilitation Unit of the San Raffaele Scientific Institute of Milan (January 2001-December 2019), collecting spirometric, ABG and OvOx parameters. To evaluate the prognostic role of each measurement, univariate Cox regression for death/tracheostomy was performed, and the variables associated with survival were selected to design a scoring system. Univariate and multivariate Cox regression analyses were then carried out to evaluate the prognostic role of the score. Finally, results were replicated in an independent cohort from the Turin ALS Center. RESULTS: The study population included 450 patients. Six measurements were found to be significantly associated with survival and were selected to design a scoring system (maximum score = 8 points). Kaplan-Meier analysis showed significant stratification of survival and time to non-invasive mechanical ventilation adaptation according to score values, and multivariate analysis confirmed the independent effect of the respiratory score on survival of each cohort. CONCLUSION: Forced vital capacity, ABG and OvOx parameters provide complementary information for the respiratory management and prognosis of MND patients and the combination of these parameters into a single score might help neurologists predict prognosis and guide decisions on the timing of the implementation of different diagnostic or therapeutic approaches.

The association of arterial partial oxygen pressure with mortality in critically ill sepsis patients: a nationwide observational cohort study.

BACKGROUND: Although several trials were conducted to optimize the oxygenation range in intensive care unit (ICU) patients, no studies have yet reached a universal recommendation on the optimal a partial pressure of oxygen in arterial blood (PaO2) range in patients with sepsis. Our aim was to evaluate whether a relatively high arterial oxygen tension is associated with longer survival in sepsis patients compared with conservative arterial oxygen tension. METHODS: From the Korean Sepsis Alliance nationwide registry, patients treated with liberal PaO2 (PaO2 ≥ 80 mm Hg) were 1:1 matched with those treated with conservative PaO2 (PaO2 < 80 mm Hg) over the first three days after ICU admission according to the propensity score. The primary outcome was 28-day mortality. RESULTS: The median values of PaO2 over the first three ICU days in 1211 liberal and 1211 conservative PaO2 groups were, respectively, 107.2 (92.0-134.0) and 84.4 (71.2-112.0) in day 1110.0 (93.4-132.0) and 80.0 (71.0-100.0) in day 2, and 106.0 (91.9-127.4) and 78.0 (69.0-94.5) in day 3 (all p-values < 0.001). The liberal PaO2 group showed a lower likelihood of death at day 28 (14.9%; hazard ratio [HR], 0.79; 95% confidence interval [CI] 0.65-0.96; p-value = 0.017). ICU (HR, 0.80; 95% CI 0.67-0.96; p-value = 0.019) and hospital mortalities (HR, 0.84; 95% CI 0.73-0.97; p-value = 0.020) were lower in the liberal PaO2 group. On ICU days 2 (p-value = 0.007) and 3 (p-value < 0.001), but not ICU day 1, hyperoxia was associated with better prognosis compared with conservative oxygenation., with the lowest 28-day mortality, especially at PaO2 of around 100 mm Hg. CONCLUSIONS: In critically ill patients with sepsis, higher PaO2 (≥ 80 mm Hg) during the first three ICU days was associated with a lower 28-day mortality compared with conservative PaO2.

[Research progress of diagnostic and therapeutic value of carbon dioxide-derived indicators in patients with sepsis].

Effectively assessing oxygen delivery and demand is one of the key targets for fluid resuscitation in sepsis. Clinical signs and symptoms, blood lactic acid levels, and mixed venous oxygen saturation (SvO2) or central venous oxygen saturation (ScvO2) all have their limitations. In recent years, these limitations have been overcome through the use of derived indicators from carbon dioxide (CO2) such as mixed veno-arterial carbon dioxide partial pressure difference (Pv-aCO2, PCO2 gap, or ΔPCO2), the ratio of mixed veno-arterial carbon dioxide partial pressure difference to arterial-mixed venous oxygen content difference (Pv-aCO2/Ca-vO2). Pv-aCO2, PCO2 gap or ΔPCO2 is not a purely anaerobic metabolism indicator as it is influenced by oxygen consumption. However, it reliably indicates whether blood flow is sufficient to carry CO2 from peripheral tissues to the lungs for clearance, thus reflecting the adequacy of cardiac output and metabolism. The Pv-aCO2/Ca-vO2 may serve as a marker of hypoxia. SvO2 and ScvO2 represent venous oxygen saturation, reflecting tissue oxygen utilization. When oxygen delivery decreases but tissues still require more oxygen, oxygen extraction rate usually increases to meet tissue demands, resulting in decreased SvO2 and ScvO2. But in some cases, even if the oxygen delivery rate and tissue utilization rate of oxygen are reduced, it may still lead to a decrease in SvO2 and ScvO2. Sepsis is a classic example where tissue oxygen utilization decreases due to factors such as microcirculatory dysfunction, even when oxygen delivery is sufficient, leading to decrease in SvO2 and ScvO2. Additionally, the solubility of CO2 in plasma is approximately 20 times that of oxygen. Therefore, during sepsis or septic shock, derived variables of CO2 may serve as sensitive markers for monitoring tissue perfusion and microcirculatory hemodynamics. Its main advantage over blood lactic acid is its ability to rapidly change and provide real-time monitoring of tissue hypoxia. This review aims to demonstrate the principles of CO2-derived variables in sepsis, assess the available techniques for evaluating CO2-derived variables during the sepsis process, and discuss their clinical relevance.