Arterial Partial Pressure Of Carbon Dioxide Research Articles

Effects of Butorphanol on Respiration in White Rhinoceros (Ceratotherium simum) Immobilized with Etorphine-Azaperone.

This article reports on respiratory function in white rhinoceros (Ceratotherium simum) immobilized with etorphine-azaperone and the changes induced by butorphanol administration as part of a multifaceted crossover study that also investigated the effects of etorphine or etorphine-butorphanol treatments. Six male white rhinoceros underwent two immobilizations by using 1) etorphine-azaperone and 2) etorphine-azaperone-butorphanol. Starting 10 min after recumbency, arterial blood gases, limb muscle tremors, expired minute ventilation, and respiratory rate were evaluated at 5-min intervals for 25 min. Alveolar to arterial oxygen gradient, expected respiratory minute volume, oxygen consumption, and carbon dioxide production were calculated. Etorphine-azaperone administration resulted in hypoxemia and hypercapnia, with increases in alveolar to arterial oxygen gradient, oxygen consumption, and carbon dioxide production, and a decrease in expired minute ventilation. Muscle tremors were also observed. Intravenous butorphanol administration in etorphine-azaperone-immobilized white rhinoceros resulted in less hypoxemia and hypercapnia; a decrease in oxygen consumption, carbon dioxide production, and expired minute ventilation; and no change in the alveolar to arterial oxygen gradient and rate of breathing. We show that the immobilization of white rhinoceros with etorphine-azaperone results in hypoxemia and hypercapnia and that the subsequent intravenous administration of butorphanol improves both arterial blood oxygen and carbon dioxide partial pressures.

Resuscitating the macro- vs. microcirculation in septic shock.

This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic shock. Current evidence from experimental and clinical observational studies in children and adults with septic shock reveals that the response to treatment and resuscitation is widely variable. Furthermore, there is a loss of hemodynamic coherence, as resuscitation-induced improvement in macrocirculation (systemic hemodynamic parameters) does not necessarily result in a parallel improvement in the microcirculation. Therefore, patient-tailored monitoring is essential in order to adjust treatment requirements during resuscitation in septic shock. Optimal monitoring must integrate macrocirculation (heart rate, blood pressure, cardiac output, and ultrasound images), microcirculation (videomicroscopy parameters and capillary refill time) and cellular metabolism (lactic acid, central venous blood oxygen saturation, and difference of central venous to arterial carbon dioxide partial pressure). There is a dire need for high-quality studies to assess the relationships between macrocirculation, microcirculation and tissue metabolism in children with septic shock. The development of reliable and readily available microcirculation and tissue perfusion biomarkers (other than lactic acid) is also necessary to improve monitoring and treatment adjustment in such patients.

Individualized estimation of arterial carbon dioxide partial pressure using machine learning in children receiving mechanical ventilation

BackgroundMeasuring arterial partial pressure of carbon dioxide (PaCO2) is crucial for proper mechanical ventilation, but the current sampling method is invasive. End-tidal carbon dioxide (EtCO2) has been used as a surrogate, which can be measured non-invasively, but its limited accuracy is due to ventilation-perfusion mismatch. This study aimed to develop a non-invasive PaCO2 estimation model using machine learning.MethodsThis retrospective observational study included pediatric patients (< 18 years) admitted to the pediatric intensive care unit of a tertiary children’s hospital and received mechanical ventilation between January 2021 and June 2022. Clinical information, including mechanical ventilation parameters and laboratory test results, was used for machine learning. Linear regression, multilayer perceptron, and extreme gradient boosting were implemented. The dataset was divided into 7:3 ratios for training and testing. Model performance was assessed using the R2 value.ResultsWe analyzed total 2,427 measurements from 32 patients. The median (interquartile range) age was 16 (12−19.5) months, and 74.1% were female. The PaCO2 and EtCO2 were 63 (50−83) mmHg and 43 (35−54) mmHg, respectively. A significant discrepancy of 19 (12–31) mmHg existed between EtCO2 and the measured PaCO2. The R2 coefficient of determination for the developed models was 0.799 for the linear regression model, 0.851 for the multilayer perceptron model, and 0.877 for the extreme gradient boosting model. The correlations with PaCO2 were higher in all three models compared to EtCO2.ConclusionsWe developed machine learning models to non-invasively estimate PaCO2 in pediatric patients receiving mechanical ventilation, demonstrating acceptable performance. Further research is needed to improve reliability and external validation.

Respiratory Infection Triggering Severe Acute Exacerbations of Chronic Obstructive Pulmonary Disease.

Data are scarce on respiratory infections during severe acute exacerbation of chronic obstructive pulmonary disease (COPD). This study aimed to investigate respiratory infection patterns in the intensive care unit (ICU) and identify variables associated with infection type and patient outcome. A retrospective, single-centre cohort study. All patients admitted (2015-2021) to our ICU for severe acute exacerbation of COPD were included. Logistic multivariable regression analysis was performed to predict factors associated with infection and assess the association between infection and outcome. We included 473 patients: 288 (60.9%) had respiratory infection and 139 (29.4%) required invasive mechanical ventilation. Eighty-nine (30.9%) had viral, 81 (28.1%) bacterial, 34 (11.8%) mixed, and 84 (29.2%) undocumented infections. Forty-seven (9.9%) patients died in the ICU and 67 (14.2%) in hospital. Factors associated with respiratory infection were temperature (odds ratio [+1°C]=1.43, P=0.008) and blood neutrophils (1.07, P=0.002). Male sex (2.21, P=0.02) and blood neutrophils were associated with bacterial infection (1.06, P=0.04). In a multivariable analysis, pneumonia (cause-specific hazard=1.75, P=0.005), respiratory rate (1.17, P=0.04), arterial partial pressure of carbon-dioxide (1.08, P=0.04), and lactate (1.14, P=0.02) were associated with the need for invasive MV. Age (1.03, P=0.03), immunodeficiency (1.96, P=0.02), and altered performance status (1.78, P=0.002) were associated with hospital mortality. Respiratory infections, 39.9% of which were bacterial, were the main cause of severe acute exacerbation of COPD. Body temperature and blood neutrophils were single markers of infection. Pneumonia was associated with the need for invasive mechanical ventilation but not with hospital mortality, as opposed to age, immunodeficiency, and altered performance status.

Correlations of IL-1β and vitamin D with CAT score in patients with acute exacerbation of chronic obstructive pulmonary disease.

This study was to analyze the correlations of IL-1β and vitamin D (VitD) with chronic obstructive pulmonary disease assessment test (CAT) score in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). For this purpose, a total of 65 patients with chronic obstructive pulmonary disease (COPD) treated in our hospital between June 2020 and June 2022 were enrolled and assigned to a research group, and 40 healthy individuals who underwent physical examination in our hospital over the same time spanning were enrolled into the control group. The 65 COPD patients were further grouped into a stability group (30 cases) and an exacerbation group (35 cases). The two groups were compared in the levels of 25-hydroxyvitamin D (25(OH)D), interleukin-1β (IL-1β) and blood gas indexes (arterial carbon dioxide partial pressure (PaCO2) and arterial partial pressure of oxygen (PaO2). The modified Medical Research Council Dyspnea Scale (mMRC) and the CAT were adopted for evaluation of the stability group and exacerbation group. The correlations of IL-1β and 25(OH)D with mMRC and CAT scores were analyzed. The diagnostic value of IL-1β and VitD in patients in different stages was analyzed through receiver operating characteristic (ROC) curves. Results showed that the control group showed greatly lower IL-1β and PaCO2 levels and higher 25(OH)D and PaO2 levels than the research group (all P<0.05). The stability group got greatly lower mMRC and CAT scores than the exacerbation group (both P<0.05). IL-1β had positive correlations with mMRC and CAT scores, while 25(OH)D had negative correlations with them (P<0.05). According to ROC curve-based analysis, IL-1β and 25(OH)D had areas under the curves of 0.814 and 0.583, respectively, in diagnosing the acute exacerbation period, and had specificities of 56.67% and 43.33%, respectively and sensitivities of 97.14% and 74.29%, respectively. In conclusion, patients with COPD have increased IL-1 β and VitD deficiency, so VitD can be properly supplemented during treatment, and the levels of inflammatory factors should be paid close attention to at all times. IL-1 β and VitD can be regarded as novel ideas for the diagnosis and treatment of COPD, which may further improve the effect of COPD prevention and treatment.

Effects of combined spinal-epidural anesthesia on anxiety, labor analgesia and motor blocks in women during natural delivery

BACKGROUND The background of this study was analgesia in natural delivery. The combined spinal-epidural anesthesia has obvious analgesic effect on the parturients in natural labor, and combined spinal-epidural anesthesia has been widely used in anesthesia for various diseases. AIM To study the effects of combined spinal-epidural anesthesia on anxiety, labor analgesia, and motor blocks in parturients during natural delivery. METHODS A total of 120 women who gave birth at Changning District Maternal and Child Health Hospital between December 2021 to December 2022 were included; a random number table approach was employed to divide the women into a control group and a joint group, with each group consisting of 60 women. The control group was given epidural anesthesia, while the joint group was given combined spinal-epidural anesthesia. The visual analog scale (VAS) was used to evaluate the degree of maternal pain. Comparisons were made between the two groups’ conditions of childbirth and the duration of labor. Apgar scores were used to evaluate the status of the newborns at birth; Self-rating Anxiety Scale (SAS) and General Self-Efficacy Scale (GSES) scores, umbilical artery blood gas analysis indices and stress indices were compared between the two groups; and the frequencies of motor block and postpartum complications were analyzed. RESULTS In comparison to the control group, in the joint group, the VAS scores for the first, second, and third stages of labor were lower (P &lt; 0.05). The rates of conversion to cesarean section and postpartum blood loss in the joint group were lower than those in the control group (P &lt; 0.05). No significant differences were observed in the Apgar score, the duration of the first stage of labor, or the total duration of labor between the two groups (P &gt; 0.05). The second and third stages of labor in the joint group were shorter than those in the control group (P &lt; 0.05). When compared to the control group, the postpartum SAS score of the joint group was lower, while the GSES score was greater (P &lt; 0.05). Between the control group and the joint group, the differences observed in pH, arterial carbon dioxide partial pressure, arterial oxygen partial pressure, or arterial hydrogen ion concentration were not significant (P &gt; 0.05). Nitric oxide, cortisol, and adrenaline levels were lower in the joint group than in the control group (P &lt; 0.05). There were no substantial differences in Bromage grade or rate of complications between the two groups (P &gt; 0.05). CONCLUSION For parturients during natural delivery, combined spinal-epidural anesthesia can reduce anxiety, provide labor analgesia, shorten labor time, and reduce postoperative stress levels but did not result in a motor block.

Сognitive impairment in patients with chronic obstructive pulmonary disease

We conducted a systematic review of 23 original studies published from 2010 to 2022, which participated a total of 168 thousand people, including 48 thousand patients with chronic obstructive pulmonary disease (COPD) aged 45 to 93 years.Results. The prevalence of cognitive impairment (CI) in patients with COPD varies from 6 to 63%. COPD patients have a higher risk of developing mild CI (HR from 1.1 to 1.9; OR from 1.4 to 2.4) and dementia (HR from 1.3 to 1.9; OR = 1.2). The risk of cognitive dysfunction increases along with a decrease in the values of forced expiratory volume in one second as a percentage of its expected value (FEV1%) (OR = 1.34), arterial oxygen partial pressure (PaO2) (OR = 5.45), oxygen saturation (SaO2) and an increase in the level of arterial carbon dioxide partial pressure (PaCO2). There is a significant direct relationship between FEV1% and Mini-Mental State Examination (MMSE) (p &lt; 0.0001) and an inverse relationship between COPD severity and MMSE (p &lt; 0.0001). The MMSE score is correlated with FEV1% (r = 0.46, p &lt; 0.01) and PaO2 (r = 0.43, p &lt; 0.05).Conclusion. The available data confirm the association of COPD with an increased risk of occurrence and progression of CI. It is discussed that this is due to the unfavorable course of concomitant vascular and neurodegenerative diseases against the background of chronic hypoxia.

Effects of lithotomy and prone positions on hemodynamic parameters, respiratory mechanics, and arterial oxygenation in percutaneous nephrolithotomy performed under general anesthesia.

The position of the body during surgery may affect the patient's body functions, especially the hemodynamic parameters. We aimed to comparatively analyze the effects of lithotomy and prone position on respiratory mechanics, arterial oxygenation, and hemodynamic parameters in patients who underwent percutaneous nephrolithotomy (PNL).

The Effect of Mometasone Furoate Nasal Spray on Blood Oxygenation in Allergic Rhinitis Patients

Allergic rhinitis (AR) is a disease that presents with symptoms like nasal discharge, blockage, and itchiness, which impair the quality of life of most patients depending on its severity. The most common symptom in AR patients is a persistent bilateral nasal blockage, which may indirectly and potentially affect the airflow into the lung. However, the symptoms can be controlled using intranasal steroid spray (INS). This study investigated the role of nasal obstruction in lowering blood oxygenation and how INS improved blood oxygenation. This study included 33 patients with AR. Subjects with moderate-to-severe nasal obstruction were recruited based on the Visual Analogue Scale (VAS), and mometasone furoate nasal spray (MFNS) – two puffs twice a day for two weeks was given. Pre- and post-medication parameters compared included nasal obstruction VAS, partial oxygen arterial pressure (PaO2), partial arterial carbon dioxide pressure (PaCO2), and oxygen saturation (O2 saturation). All parameters were substantially different between pre- and post-medication. VAS, PaO2, PaCO2, and O2 saturation were significantly different before and after medicine (p&lt;0.01). A comprehensive treatment of nasal obstruction using MFNS helps improve blood oxygenation and nasal obstruction in AR patients.

Elevated methemoglobin levels in patients treated with high-dose hydroxocobalamin.

The aim of this study was to assess the impact of hydroxocobalamin (OHCbl) infusion on arterial blood gas and oximetry values in patients with vasoplegic syndrome. Blood samples collected from 95 patients receiving OHCbl infusion were assayed using the ABL90 FLEX Plus blood gas analyzer for the concentration of methemoglobin (MetHb), total hemoglobin (tHb), carboxyhemoglobin (COHb), arterial oxygen saturation (SaO2), arterial oxygen partial pressure (PaO2), and arterial carbon dioxide partial pressure (PaCO2). Interference of OHCbl on these variables was evaluated using the measured difference between the preinfusion and postinfusion samples. Blood MetHb (%) measured after the infusion of OHCbl (5g) were significantly higher than the baseline levels, with a median of 4.8 (IQR, 3.0-6.5) versus 1.0 (IQR, 1.0-1.2) (P < .001). Blood COHb (%) increased from a median of 1.3 (IQR, 1.0-1.8) to 1.7 (IQR, 1.3-2.2) (P < .001) following the OHCbl infusion. No differences were seen in median levels of tHb, PaO2, PaCO2, and SaO2 between pre- and post-OHCbl treatment. The presence of OHCbl in blood clearly interfered with the oximetry measurements of the hemoglobin component fractions by falsely increasing the levels of MetHb and COHb. Blood levels of MetHb and COHb cannot be reliably determined by the co-oximetry when OHCbl is known or suspected.

Comparison of Hemodynamic Effects of Dobutamine and Ephedrine Infusions in Isoflurane-Anesthetized Horses.

The objective of this study was to compare the hemodynamic effects of dobutamine and ephedrine during the management of anesthesia-related hypotension in healthy horses. Thirteen horses underwent general anesthesia with isoflurane and were randomly divided into two different groups, one of which received a dobutamine constant rate infusion (CRI) (1 µg/kg bwt/min) and the other received an ephedrine CRI (20 µg/kg bwt/min) when hypotension (<60 mmHg) was identified, following up to 15 min after the blood pressure reached 70 mmHg. All horses were equipped with a pulmonary artery catheter and a peripheral artery catheter, and multiparameter monitoring commenced as soon as they were under mechanical ventilation. Hemodynamic parameters were recorded, while tissue perfusion markers (peripheral oxygen saturation, arterial oxygen partial pressure, arterial carbon dioxide partial pressure, arterial pH, arterial plasma bicarbonate concentration, arterial oxygen saturation, mixed venous oxygen saturation, mixed venous oxygen content, arterial oxygen content, arteriovenous oxygen difference, oxygen delivery index, oxygen consumption index, and oxygen extraction ratio), serum lactate concentration, and troponin I concentrations were analyzed before the start of infusions (T0), when the blood pressure reached 70 mmHg (T1), and 15 min after T1 (T2). The time to restore the arterial pressure was similar in both groups (p > 0.05); however, the heart rate was higher in the ephedrine group (p = 0.0098), and sinus bradyarrhythmia occurred in the dobutamine group. Furthermore, both experimental protocols increased cardiac output (p = 0.0012), cardiac index (p = 0.0013), systemic vascular resistance (p = 0.008), systemic vascular resistance index (p < 0.001), and ameliorated perfusion markers. In the dobutamine group, the pulmonary artery wedge pressure (p < 0.001) and systolic index (p = 0.003) were elevated, while the arteriovenous oxygen difference was reduced in the ephedrine group (p = 0.02). Troponin I was used as a myocardial injury indicator, and did not differ between moments or between groups (p > 0.05). We concluded that both drugs were effective and safe to treat anesthetic hypotension under the conditions of this study.

Relationship between Initial Lactate Level with Mortality in Children with Sepsis and Septic Shock: A Comparison with the PRISM-3 Score

Abstract Objective Sepsis and septic shock are leading causes of mortality and morbidity in intensive care units. Our study aimed to compare the pediatric risk of mortality (PRISM-3) score, which is used for predicting mortality risk among critically ill patients in pediatric intensive care units, with laboratory parameters, particularly lactate parameters. Methods This study included 38 patients aged 1 month to 18 years who were managed for sepsis and septic shock in a pediatric intensive care unit. Lactate, D-dimer, troponin T, and N-terminal prohormone of brain natriuretic peptide levels were measured at the 0th and 24th hours. The patients were divided into survivors and nonsurvivors and those with septic shock and those without. Results There were a total of 38 patients with a median age of 12 months, of whom 17 (44.7%) were males and 21 (55.3%) were females. Six (15.8%) patients died within 7 days after the diagnosis. Nonsurvivors had significantly higher median values of PRISM-3 (p = 0.002), C-reactive protein (p = 0.046), and partial arterial carbon dioxide pressure (p = 0.041). PRISM-3 showed a good discriminatory power (area under the curve [AUROC] = 0.878; p &lt; 0.0001) and baseline lactate level showed a moderate level of discriminatory power (AUROC = 0.734 p = 0.0254) for early mortality within 7 days. Conclusion PRISM-3 and baseline lactate predict early mortality in children with sepsis and septic shock. We suggest that adding lactate, which is not included in the PRISM-3 score, to the score may increase the score's predictive ability for mortality. We believe, however, that randomized, controlled, multicenter studies with larger sample sizes should be conducted to test this hypothesis.

High-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy but not to non-invasive mechanical ventilation in reducing intubation rate in hypoxia and dyspnea due to acute heart failure: a systematic review and meta-analysis.

High-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy but not to non-invasive mechanical ventilation in reducing intubation rate in hypoxia and dyspnea due to acute heart failure: a systematic review and meta-analysis.

Noninvasive carbon dioxide monitoring in pediatric patients undergoing laparoscopic surgery: transcutaneous vs. end-tidal techniques

PurposeThe present study aimed to investigate the correlation between transcutaneous carbon dioxide partial pressure (PtcCO2) and arterial carbon dioxide pressure (PaCO2) and the accuracy of PtcCO2 in predicting PaCO2 during laparoscopic surgery in pediatric patients.MethodsChildren aged 2–8 years with American Society of Anesthesiologists (ASA) class I or II who underwent laparoscopic surgery under general anesthesia were selected. After anesthesia induction and tracheal intubation, PtcCO2 was monitored, and radial arterial catheterization was performed for continuous pressure measurement. PaCO2, PtcCO2, and end-tidal carbon dioxide partial pressure (PetCO2) were measured before pneumoperitoneum, and 30, 60, and 90 min after pneumoperitoneum, respectively. The correlation and agreement between PtcCO2 and PaCO2, PetCO2, and PaCO2 were evaluated.ResultsA total of 32 patients were eventually enrolled in this study, resulting in 128 datasets. The linear regression equations were: PtcCO2 = 7.89 + 0.82 × PaCO2 (r2 = 0.70, P < 0.01); PetCO2 = 9.87 + 0.64 × PaCO2 (r2 = 0.69, P < 0.01). The 95% limits of agreement (LOA) of PtcCO2 – PaCO2 average was 0.66 ± 4.92 mmHg, and the 95% LOA of PetCO2 – PaCO2 average was –4.4 ± 4.86 mmHg. A difference of ≤ 5 mmHg was noted between PtcCO2 and PaCO2 in 122/128 samples and between PetCO2 and PaCO2 in 81/128 samples (P < 0.01).ConclusionIn pediatric laparoscopic surgery, a close correlation was established between PtcCO2 and PaCO2. Compared to PetCO2, PtcCO2 can estimate PaCO2 accurately and could be used as an auxiliary monitoring indicator to optimize anesthesia management for laparoscopic surgery in children; however, it is not a substitute for PetCO2.Registration number of Chinese Clinical Trial RegistryChiCTR2100043636.

Clinical characteristics and early prediction of mortality risk in patients with acute organophosphate poisoning-induced shock.

To further get insights of clinical characteristics of acute organophosphate poisoning-induced shock, investigate the relationship between shock and prognosis, and screen risk indicators for prognosis. A total of 73 patients with acute organophosphate poisoning admitted to our hospital between January 2014 and December 2021 were enrolled in this retrospective study. Patients were divided into the shock group and the non-shock group. The pH value of blood, arterial blood carbon dioxide partial pressure (PaCO2), arterial partial pressure of oxygen (PaO2), base excess (BE), lactic acid (Lac), serum albumin (ALB), total bilirubin (TBIL), alanine aminotransferase (ALT), serum creatinine (Cr), serum potassium (K), serum calcium (Ca), serum sodium (Na), blood chloride (Cl), serum troponin I (cTNI), brain natriuretic peptide (BNP), white blood cell count (WBC), hemoglobin (HGB), platelet count (PLT), and other clinical indicators of patients were recorded. Incidence of shock, time of shock onset, and outcomes of patients were also recorded. Cox proportional hazards regression models were performed for analysis. The incidence of organophosphate poisoning-induced shock was 30.1% (22/73), and 72.7% of shock patients developed shock blood pressure within 6 h. The levels of blood lactate, ALT, Cr, cTNI, BNP, and Cl in the shock group were significantly higher than those in the non-shock group, while the level of Ca and pH value was significantly lower than that in the non-shock group (all p < 0.05). Moreover, compared with patients without shock (2.0%), the mortality rate was significantly increased in patients with shock (36.4%), which was supported by the results from adjusted Cox proportional hazards regression model. We found that shock and elevated serum creatinine were associated with increased risk of death in patients with organophosphate poisoning (shock: HR, 10.9; 95% CI 1.2-96.3; elevated serum creatinine: HR, 1.0, 95% CI 1.0-1.0). This study indicated the association between elevated serum creatinine and increased mortality rates in patients with organophosphate poisoning, highlighting the importance of the comprehensive management of shock, especially the control of renal function, in these poisoning patients.

Correlation of venous to arterial carbon dioxide partial pressure difference with other cardiac output indices in patients undergoing intracardiac repair for tetralogy of fallot.

Clearance of tissue carbon dioxide by circulation is measured by venous to arterial carbon dioxide partial pressure difference (AVCO2) and is correlated with cardiac output (CO) in critically ill adult patients. This study aimed to correlate AVCO2 with other CO indices like arteriovenous oxygen saturation difference (AVO2), central venous oxygen saturation (ScVO2), and serum lactate in pediatric patients undergoing intracardiac repair (ICR) for tetralogy of Fallot (TOF). We conducted a prospective observational study in 50 patients, of age 5 months to 5 years, undergoing ICR for TOF and analyzed AVO2, AVCO2, ScVO2, and lactate from arterial and venous blood gas pairs obtained at different time intervals from admission to pediatric intensive care unit (PICU) (T0), at 6 h (T1), 12 h (T2), 24 h (T3), and 48 h (T4) postoperatively. Bivariate correlations were analyzed using Pearson for parametric variables. Admission AVCO2 was not correlated with AVO2 (R2 = 0.166, P = 0.246), ScVO2 (R2 = -2.2, P = 0.124), and lactate (R2 = -0.07, P = 0.624). At T1, AVCO2 was correlated with AVO2 (R2 = 0.283, P = 0.0464) but not with ScVO2 (R2 = - 0.25, P = 0.079) and lactate (R2 = -0.07, P = 0.623). At T2, T3 and T4, AVCO2 was correlated with AVO2 (R2 = 0.338,0.440 & 0.318, P = 0.0162, 0.0013, and 0.024), ScVO2 (R2 = - 0.344, - 0.488, and -0.366; P = 0.0143, <0.0001, and 0.017), and lactate (R2 = 0.305, 0.467 and 0.607; P = 0.0314, 0.00062 and <0.0001). AVCO2 was negatively correlated with ScVO2. No correlation observed between admission AVCO2 and mechanical ventilation duration. Two nonsurvivors had higher value of admission AVCO2 compared to survivors. AVCO2 is correlated with other CO surrogates like AVO2, ScVO2, and lactate in pediatric patients undergoing ICR for TOF.

The Development of the Acoustic Capnometer

We developed an acoustic capnometer to estimate the partial pressures of arterial carbon dioxide from expired air in the pulmonary rehabilitation devices for patients with respiratory failure. Because partial pressures of carbon dioxide reduce the velocity of sound propagating through expired air, we developed an acoustic capnometer. The present study proposes a unique method based on the measurement of acoustic velocity in expired air, thus eliminating the use of a specific carbon dioxide sensor. The current method can fabricate the capnometer at an appreciably low cost, enabling the device to be used for various rehabilitation purposes. The acoustic capnometer comprises a cylindrical small sample cavity, an ultrasonic transmitter-receiver system, electronic circuits for velocity determination, and a microprocessor for data processing. To validate the device, 12 patients with pulmonary disease were enrolled, and end-tidal partial pressures of carbon dioxide obtained from the current device were compared to the carbon dioxide tension measured by conventional arterial blood gas analysis. The results show a linear relationship in the region of interest (40–60 torr). Therefore, the proposed device facilitates the estimation arterial carbon dioxide partial pressures without sampling blood.

Changes of blood gas analysis in moderate-to-severe acute respiratory distress syndrome patients during long-term prone position ventilation: a retrospective cohort study.

Prone position ventilation (PPV) has been recommended for patients with acute respiratory distress syndrome (ARDS) to improve oxygenation. However, whether prolonged prone ventilation will aggravate hyperoxia and whether abdominal compression will aggravate permissive hypercapnia acidosis are topics of concern. We carried out a retrospective analysis to investigate the issues above. Clinical data were collected from 97 moderate-to-severe ARDS patients who received PPV as part of their treatment in the intensive care unit (ICU) of the First Affiliated Hospital of Guangzhou Medical University from November 2015 to May 2021. We collected arterial blood gas of patients according to the 3 periods: supine position ventilation (SPV), PPV early stage (within 4 hours), and PPV middle and late stage (6 hours or later). We established a linear mixed-effects models with "body position changes, times of PPV, gender, age, baseline SOFA, and baseline APACHE II" as fixed effects, and individual and the number of prone positions as random intercept and random slope to investigate the effect of body position changes on blood gas analysis. Among the 97 patients received PPV included, 51 were ICU survivors. Arterial partial pressure of oxygen (PaO2) and PaO2/fraction of inspired oxygen (FiO2) ratio were significantly higher at the early, middle and late stages of PPV than those in SPV [PFR (mmHg): 158 (118.00, 203.00) vs. 161 (129.00, 202.75) vs. 123 (91.75, 163.00), P<0.05]. Despite the synchronized reduction of FiO2, the incidence of hyperoxia in the prone position was still significantly higher than that in the supine position [hyperoxia (%):33.33 vs. 33.56 vs. 12.42, P<0.05]; there was no significant change in arterial carbon dioxide partial pressure (PaCO2) at each stage of PPV, but there was a significant increase in PH at PPV middle and late stages than those at early stage [PH: 7.39 (7.34, 7.42) vs. 7.37 (7.31, 7.41), P<0.05]. Although PPV improves the patients' oxygenation, the associated incidence of hyperoxia exceeds 33%. Down-regulate FiO2 more sharply after PPV is necessary, if oxygenation conditions permit. PPV may alleviate the acidosis associated with permissive hypercapnia in ARDS patients treated with lung protective ventilation strategy (LPVS).

Comparison of mainstream (Capnostat 5) and a low-flow sidestream capnometer (Capnostream) in mechanically-ventilated rabbits anesthetized with a Bain coaxial breathing system.

Introduction: Measurement of end-tidal carbon dioxide (PE'CO2) provides continuous non-invasive estimation of arterial carbon dioxide partial pressure (PaCO2). Agreement can be affected by the high respiratory rates and shallow tidal volumes of rabbits, especially when anesthetizing with a non-rebreathing system and high fresh gas flows. Capnometer function may be improved by increasing tidal volume and decreasing respiratory rate with mechanical lung ventilation.

Effects of Thoracic Paravertebral Block on Postoperative Analgesia in Infants and Small Children undergoing Ultra-Fast Track Cardiac Anesthesia: A Randomized Controlled Trial

To assess whether a preoperative bilateral thoracic paravertebral block (TPVB) would improve postoperative analgesia in infants and small children undergoing open cardiac surgery in the protocol of an ultra-fast track cardiac anesthesia (UFTCA). A single-center, prospective, randomized, controlled study. At a tertiary children's medical center. A total of 180 children undergoing cardiac surgery, aged 1 month to 3 years. Patients are allocated randomly to TPVB and parent- and/or nurse-controlled intravenous analgesia (PNCA) group (Group T) or PNCA group (Group P). The primary outcome is the postoperative pain scores. The secondary outcome are intraoperative consumption of sufentanil, time to extubation, using of neostigmine, cumulative total and invalid PCA attempts in 24 and 48 hours after surgery, hospitalization characteristics, perioperative blood glucose, postoperative arterial oxygen partial pressure, arterial carbon dioxide partial pressure (PaCO2) and brain natriuretic peptide (BNP). The postoperative pain scores within 24 hours, intraoperative consumption of sufentanil, total, and invalid PCA attempts in 24 and 48 hours, perioperative blood glucose and BNP on the seventh day in Group T were all significantly lower than those in Group P (p < 0.001). The time to extubation, the use of neostigmine, and PaCO2 on the sixth hour, postoperatively, were significantly smaller in Group T than those in Group P (p < 0.05). There were no significant differences in the hospitalizations between the 2 groups. A combination of bilateral single dose TPVB and PNCA pain management is superior to a PNCA pain management alone in infants and small children undergoing open cardiac surgery and contributes to a rapid recovery with preferable perioperative outcomes in the protocol of UFTCA.