Arterial Blood pH Research Articles

Effects of a convertible to-and-fro and circle anesthetic system on cardiopulmonary variables in isoflurane anesthetized horses

Six healthy adult horses two male and four female, mean body weight of 424 + 44.1kg, were anesthetized with xylazine, ketamine/diazepam and isoflurane for 60 minutes using a convertible to-and-fro and circle system. Variables analyzed were arterial blood pH, carbon dioxide partial pressure (PaCO 2 ) and oxygen partial pressure (PaO 2 ), respiratory rate(RR), and blood pressure. The horses were allowed to breath spontaneously, and were positioned in right lateral recumbency. The arterial O 2 values were significantly higher during isoflurane anesthesia when compared to the baseline values, and significantly lower after induction with ketamine/diazepam although arterial hypoxemia were not present. The arterial PCO 2 values were significantly higher from baseline values during isoflurane anesthesia occurring arterial hypercapnia and mild respiratory acidosis. The arterial pH changes paralleled the changes in PaCO 2 . Respiratory rate values were significantly lower during isoflurane anesthesia when compared to baseline values. All values remained within accepted range for lateral recumbent spontaneously breathing anesthetized horses. There were no significant differences between the circle and the to-and-fro system, demonstrating that either system is safe to maintain isoflurane anesthesia in adult horses.

“The Proof is in the Pudding”: Do SGLT2 Inhibitors Cause Diabetic Ketoacidosis?

Abbreviations: DKA diabetic ketoacidosis EuDKA euglycemic diabetic ketoacidosis SGLT2i sodium-glucose cotransporter 2 inhibitors T2DM type 2 diabetes mellitus

Effects of dexmedetomidine combined with commonly administered opioids on clinical variables in dogs.

OBJECTIVE To evaluate cardiopulmonary, sedative, and antinociceptive effects of dexmedetomidine combined with commonly administered opioids in dogs. ANIMALS 8 healthy Beagles. PROCEDURES Dogs were sedated by IM administration of each of 7 treatments. Treatments comprised dexmedetomidine (0.01 mg/kg; Dex) and the same dose of dexmedetomidine plus butorphanol (0.15 mg/kg; Dex-But), meperidine (5 mg/kg; Dex-Mep), methadone (0.5 mg/kg; Dex-Meth), morphine (0.5 mg/kg; Dex-Mor), nalbuphine (0.5 mg/kg; Dex-Nal), or tramadol (5 mg/kg; Dex-Tram). Cardiorespiratory and arterial blood gas variables and sedative and antinociceptive scores were measured before drug injection (time 0; baseline) and at 15-minute intervals for 120 minutes. RESULTS Heart rate was reduced at all time points after injection of Dex-But, Dex-Mep, Dex-Meth, and Dex-Mor treatments. There was a significant reduction of mean arterial blood pressure for Dex-But, Dex-Mep, and Dex-Mor treatments at all time points, compared with baseline. There was a significant decrease in respiratory rate, compared with the baseline value, for Dex, Dex-But, Dex-Meth, and Dex-Tram treatments from 15 to 120 minutes. A significant decrease in arterial blood pH was detected from baseline to 120 minutes for all treatments, with differences among Dex, Dex-Mep, and Dex-Mor. Reduction in Pao2 was greater for the Dex-Mep treatment than for the other treatments. The highest sedation scores were detected for Dex-Mep and Dex-Meth treatments. Antinociceptive effects were superior for Dex-But, Dex-Meth, Dex-Mor, and Dex-Nal treatments. CONCLUSIONS AND CLINICAL RELEVANCE Drug combinations caused similar cardiorespiratory changes, with greater sedative effects for Dex-Mep and Dex-Meth and superior antinociceptive effects for Dex-But, Dex-Meth, Dex-Mor, and Dex-Nal.

Prediction of adverse perinatal outcome by cerebroplacental ratio adjusted for estimated fetal weight

To evaluate the relationship between cerebroplacental ratio (CPR) and estimated fetal weight (EFW) in low- and high-risk singleton pregnancies. Furthermore, we evaluated the role of CPR in the prediction of adverse perinatal outcome and whether CPR measurements adjusted for EFW improve its predictive value. This was a retrospective cohort study including pregnancies in which Doppler investigations of umbilical artery (UA) and fetal middle cerebral artery (MCA) were performed at ≥ 30 weeks' gestation. Pregnancies were allocated to one of three groups according to EFW centile: small-for-gestational age (SGA) with EFW < 10th centile, appropriate-for-gestational age (AGA) and large-for-gestational age (LGA) with EFW > 90th centile. CPR was calculated as the ratio between the UA pulsatility index (PI) and MCA-PI and converted to CPR multiples of the median (MoMs) according to the three EFW groups. Linear regression analysis was performed to evaluate the relationship between CPR-MoMs and EFW centiles in low-risk pregnancies. Furthermore, MoMs of CPR adjusted according to EFW centile (aCPR-MoMs) were calculated. Adverse perinatal outcome was defined as presence of pathological cardiotocography (CTG) trace, arterial cord blood pH < 7.1, 5-min Apgar score < 7 and presence of meconium-stained amniotic fluid (MSAF). A total of 3515 (3016 low risk and 499 high risk) pregnancies, delivered between January 2010 and March 2016, were included. Linear regression analysis revealed a significant positive correlation between EFW centile and CPR-MoM. Receiver-operating characteristics (ROC) curve analysis showed a significant association between CPR-MoM and pathological CTG trace (AUC, 0.539; SD, 0.014; P = 0.005) and low Apgar score (AUC, 0.609; SD, 0.041; P = 0.008), but not with low arterial pH or MSAF. There was a significant association between aCPR-MoM and pathological CTG trace (AUC, 0.540; SD, 0.014; P = 0.003), low arterial cord blood pH (AUC, 0.546; SD, 0.022; P = 0.035) and low Apgar score (AUC, 0.609; SD, 0.044; P = 0.008), but not with MSAF. However, detection rates for adverse perinatal outcomes by CPR-MoM and aCPR-MoM were low, ranging from 6.7% to 28.6% for SGA, 12.1% to 22.2% for AGA and 0% to 33.3% for LGA, for a false-positive rate of 10%. In a subgroup analysis of cases in which ultrasound examination was performed at ≥ 34 weeks of gestation and within 4 weeks of delivery (n = 1439), the ROC curves for aCPR-MoM were significantly associated with all four outcomes evaluated. CPR-MoM values are dependent on EFW centiles; therefore, we suggest that CPR-MoM should be adjusted for EFW centile. However, both CPR- and aCPR-MoM showed a low prediction rate for adverse perinatal outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Immediate and short-term outcome of septoplasty with nasal packing with reference to the effect of arterial blood gases’ concentrations

Objectives To evaluate the outcome of septoplasty and the effect of bilateral anterior nasal packing (NP) on surgical outcome and postoperative (PO) arterial blood gas levels. Patients and methods A total of 90 patients underwent septoplasty: group I included patients who received PO bilateral anterior NP at the end of surgery for 48 h and group II included patients free of NP. Patients were evaluated clinically using the Nasal Obstruction and Septoplasty Effectiveness scale and underwent septoplasty using Cottle’s technique. Arterial blood samples were obtained preoperatively and before NP removal for estimation of arterial blood pH, bicarbonate (HCO3−), partial pressure of O2 (PaO2) and CO2 (PaCO2), and O2 saturation (SaO2) levels. Pain severity was assessed using numeric rating scale at 6 h, D-1, and D-2 PO, and during the first 48 h PO, nasal bleeding in group II was estimated. After NP removal, pack removal-associated pain and amount of bleeding were determined. Results Operations were conducted uneventfully with nonsignificant difference between groups. At 48 h PO, mean PaO2, PaCO2, and SaO2 levels were significantly lower in all patients than preoperative levels, with significantly lower SaO2 and PaCO2 levels in patients of group I than group II. Numeric rating scale pain scores in both groups showed progressive significant decrease till 48 h PO, with significantly lower scores in group II. Removal of NP resulted in pain scored by more than or equal to 4 in 30 patients and induced minimal bleeding, which was significantly lower than bleeding occurred in patients of group II throughout the 48 h PO. All patients enjoyed significant reduction of Nasal Obstruction and Septoplasty Effectiveness score, with nonsignificant difference between both groups. Conclusion NP after septoplasty reduced amount of PO bleeding, but pain associated with NP presence and removal-induced deleterious effect on patients’ satisfaction with deleterious effect on arterial blood O2 and CO2 levels but with nonsignificant effect on arterial blood pH or HCO3 concentration.

Comparison of the anesthetic effects of 2,2,2-tribromoethanol on ICR mice derived from three different sources

This study was conducted to compare the anesthetic effects of 2,2,2-tribromoethanol (TBE, Avertin®) in ICR mice obtained from three different sources. TBE (2.5%) was intraperitoneally injected at three doses: high-dose group (500 mg/kg), intermediate-dose group (250 mg/kg), and low-dose group (125 mg/kg). Anesthesia time, recovery time, end-tidal peak CO2 (ETCO2), mean arterial blood pressure, heart rate, oxygen saturation (SpO2), body temperature, pH, PCO2, and PO2 of the arterial blood were measured. Stable anesthesia was induced by all doses of TBE and the anesthesia time was maintained exhibited dose dependency. No significant differences in anesthetic duration were found among the three different strains. However, the anesthesia time was longer in female than in male mice, and the duration of anesthesia was significantly longer in female than in male mice in the high-dose group. The recovery time was significantly longer for female than male mice in the intermediate- and high-dose groups. In the ICR strains tested, there were no significant differences in the mean arterial blood pressure, SPO2, arterial blood PCO2, and PO2, which decreased after TBE anesthesia, or in heart rate and ETCO2, which increased after TBE anesthesia. In addition, body temperature, blood biochemical markers, and histopathological changes of the liver, kidney, and lung were not significantly changed by TBE anesthesia. These results suggested that ICR mice from different sources exhibited similar overall responses to a single exposure to TBE anesthesia. In conclusion, TBE is a useful drug that can induce similar anesthetic effects in three different strains of ICR mice.

The Assessment of Association between Uterine Artery Pulsatility Index at 30-34 Week's Gestation and Adverse Perinatal Outcome.

Background:Given the high prevalence of adverse perinatal outcome in the developing countries and the association between uterine artery (UtA) blood flow and fetal status in the uterine, in the current study, we assess the association between UtA pulsatility index (UtA-PI) at 30–34 week's gestation and adverse perinatal outcome.Materials and Methods:This cohort study included 100 pregnant women at 30–34 weeks’ gestation. At baseline, UtA-PI was evaluated with color Doppler through abdominal ultrasound. Then, adverse perinatal outcomes including preterm labor, intrauterine fetal death, preeclampsia, low 5-min Apgar score (<7), low umbilical arterial cord blood pH, admitted to Intensive Care Unit in the first 3 days of birth, low birth weight, infant with low weight, death of newborns, cesarean section for respiratory distress, and meconial amniotic fluid were recorded. Ultimately, the collected data were analyzed using SPSS, version 20.Results:The presence of small-for-gestational-age fetuses indicated the highest prevalent adverse prenatal outcome with the incidence of 13.3% and 58.5%, respectively, among pregnancies with normal UtA-PI as well as those with high UtA-PI (P < 0.001). Overall, given that sensitivity and specificity of high UtA-PI were 37.5% and 73.3%, respectively, it could not properly predict adverse perinatal outcome (P = 0.360).Conclusion:According to the results, although the incidence of some of adverse perinatal outcomes in pregnant women with high UtA-PI was higher compared to those with normal UtA-PI, this factor alone cannot predict adverse perinatal outcome well. Therefore, this factor may predict these outcomes well, in the subgroups with high-risk pregnancies or with some blood factors or with pregnancy complications.

Acid-base regulation in the air-breathing swamp eel (Monopterus albus) at different temperatures.

Vertebrates reduce arterial blood pH (pHa) when body temperature increases. In water breathers, this response occurs primarily by reducing plasma HCO3- levels with small changes in the partial pressure of CO2 (PCO2 ). In contrast, air breathers mediate the decrease in pHa by increasing arterial PCO2 (PaCO2 ) at constant plasma HCO3- by reducing lung ventilation relative to metabolic CO2 production. Much less is known about bimodal breathers, which utilize both water and air. Here, we characterized the influence of temperature on arterial acid-base balance and intracellular pH (pHi) in the bimodal-breathing swamp eel, Monopterus albus This teleost uses the buccopharyngeal cavity for gas exchange and has very reduced gills. When exposed to ecologically relevant temperatures (20, 25, 30 and 35°C) for 24 and 48 h, pHa decreased by -0.025 pH units (U)°C-1 in association with an increase in PaCO2 , but without changes in plasma [HCO3-]. pHi was also reduced with increased temperature. The slope of pHi of liver and muscle was -0.014 and -0.019 U °C-1, while the heart muscle showed a smaller reduction (-0.008 U °C-1). When exposed to hypercapnia (7 or 14 mmHg) at either 25 or 35°C, M. albus elevated plasma [HCO3-] and therefore seemed to defend the new pHa set-point, demonstrating an adjusted control of acid-base balance with temperature. Overall, the effects of temperature on acid-base balance in M. albus resemble those in air-breathing amniotes, and we discuss the possibility that this pattern of acid-base balance results from a progressive transition in CO2 excretion from water to air as temperature rises.

Effect of Transcutaneous Acupoint Electrical Stimulation on Hemodynamic Fluctuation Caused by Loosing Tourniquet in Elderly Patients Undergoing Knee Joint Replacement

To observe the effect of transcutaneous acupoint electrical stimulation (TAES) on hemodynamic fluctuation caused by loosing tourniquet in the elderly patients undergoing knee joint replacement. A total of 60 ASA (America Society Anesthesiologist) I or II elderly patients for elective knee joint replacement surgery were randomly divided into control group (30 cases) and TAES group (30 cases). Patients of both groups were treated by intravenous anesthesia, and monitored with bispectral index (BIS, between 45－60) for anesthesia depth, stroke volume variation (SVV) for fluid management, mean arterial pressure (MAP) and cardiac index (CI) for hemodynamic fluctuation evaluation, and with analgesia nociception index (ANI, between 50－70) for remifentanil dosage adjustment. TAES (2 Hz/100 Hz, 8－20 mA) was applied to bilateral Xinshu (BL 15), Feishu (BL 13), Neiguan (PC 6) and Hegu (LI 4) acupoints for 30 min first (followed by anesthesia induction and operation), and given continuously until 15 min after tourniquet loosing. Patients of the control group were only given with electrodes attachment without electrical stimulation. The levels of MAP, CI, and arterial blood pH, PaCO2, PaO2, base excess (BE) and lactic acid (Lac) 1 min before, and 5 and 15 min after tourniquet loosing, and the dosages of remifentanil and ephedrine after tourniquet loosing were recorded. The changed levels of MAP, CI and blood Lac at 5 min after tourniquet loosing (relevant to the baseline levels), and blood Lac content at 15 min after tourniquet loosing (relevant to 5 min after tourniquet loosing) were significantly lower in the TAES group than in the control group (P<0.05), but the levels of MAP and CI at 15 min after tourniquet loosing (relevant to 5 min following tourniquet loosing) were significantly higher in the TAES group than in the control group (P<0.05), suggesting an improvement of blood pressure, cardiac function and substance metabolism after TAES. Moreover, the dosages of remifentanil and ephedrine after tourniquet loosing were considerably lower in the TAES group than in the control group (P<0.05), suggesting a better stabilization of hemodynamics after TAES. No significant differences were found between the two groups in the levels of blood pH, PaCO2, PaO2 and BE at 5 and 15 min after tourniquet loosing (P>0.05). TAES has a positive effect on hemodynamics fluctuation caused by loosing tourniquet in the aged patients undergoing knee joint replacement.

Clinical Outcome of Urgent Thoracotomy in Patients with Penetrating and Blunt Chest Trauma: A Retrospective Survey.

In contrast to an emergency department of thoracotomy (EDT), an urgent thoracotomy (UT) is defined as a surgical thoracic intervention performed in the operating room within the first 48 hours of the patient's intensive care unit (ICU) stay. The factors affecting survival after UT are not fully understood. In this study, we retrospectively analyzed the clinical data and outcome of patients with blunt and penetrating chest injuries who underwent UT. All adult patients who had blunt or penetrating chest trauma and who underwent UT, were included in the study. All data were collected from the patients' hospital and ICU records. Forty-five patients with thoracic injuries who underwent UT during the first 48 hours of ICU stay were analyzed. Of these, 25 had penetrating chest injuries, and 20 had blunt thoracic injuries. Of the penetrating injuries, 16 were stab wounds, and 9 were gunshot wounds. Overall ICU mortality was 29% (n = 13) and was significantly higher in the blunt chest trauma group than in the penetrating trauma group (45% vs 16%; p = 0.04). Lung parenchyma injuries (lacerations and contusions) were the most common intraoperative findings in both groups. The following independent predictors of in-hospital mortality were found: an Injury Severity Score (ISS) of >40; an Acute Physiology and Chronic Evaluation II (APACHE II) score of >30; prolonged duration of UT; low body temperature on admission to the ED; abnormal arterial blood lactate, bicarbonate, and pH at the end of UT; and use of vasopressors during the first 24 hours of ICU stay. Mortality after UT was higher in patients with blunt chest trauma. The UT should be performed in both penetrating and blunt chest trauma as quickly as possible and should be limited to damage control. It also emerges that acidosis and hypothermia in chest trauma patients need to be treated extremely aggressively before, during, and after UT.

The comparison of umbilical cord arterial blood lactate and pH values for predicting short-term neonatal outcomes

ObjectiveCurrent clinical practice of assessing neonatal condition is based on evaluation of umbilical cord arterial blood pH value rather than lactate. However, evidence shows that lactate is direct and more predictive measurement than pH or at least of equal importance. This study is to assess and compare umbilical cord arterial lactate and pH values for predicting short-term neonatal outcomes. Materials and methodsA retrospective cohort study was conducted at the tertiary level hospital, were arterial umbilical cord blood sampling was collected according to the standard procedures. Neonatal morbidity was registered if at least one of the following conditions was noted: Apgar score at 1 min after delivery was 6 or lower, resuscitation performed, including assisted ventilation and requirement of admission to neonatal intensive care unit. Mothers–newborns pairs were allocated into two groups: newborns exposed to perinatal hypoxia (group 1) and observed as healthy newborns (group 2). Receiver operating characteristics curves (ROC) were generated to assess the predictive ability of pH and lactate for the short-term neonatal outcomes. Results901 neonates born at ≥37 weeks of gestation were included. Newborns exposed to perinatal hypoxia (group 1) encompassed 39 (4.3%) patients, and observed as healthy (group 2) – 862 (95.7%). Arterial umbilical cord blood pH in group 1 was 7.160 ± 0.126 as compared to 7.314 ± 0.083 in group 2; p < 0.001. Mean arterial lactate was significantly higher in group 1 than group 2 (6.423 ± 2.335 as compared to 3.600 ± 1.833; p < 0.001). The difference between areas under ROC curves representing pH and lactate was not significant (0.848 and 0.831 respectively; p = 0.6132). ConclusionUmbilical cord arterial lactate and pH predicted short-term neonatal outcomes with similar efficacies.

The physiology of the Tambaqui (Colossoma macropomum) at pH 8.0.

The Tambaqui is a model neotropical teleost which is of great economic and cultural importance in artisanal fisheries and commercial aquaculture. It thrives in ion-poor, often acidic Amazonian waters and exhibits excellent regulation of physiology down to water pH 4.0. Curiously, however, it is reported to perform poorly in aquaculture at pH 8.0, an only slightly alkaline pH which would be benign for most freshwater fish. In initial experiments with Tambaqui of intermediate size (30-50g), we found that ammonia excretion rate was unchanged at pH 4, 5, 6, and 7, but elevated after 20-24h at pH 8, exactly opposite the pattern seen in most teleosts. Subsequent experiments with large Tambaqui (150-300g) demonstrated that only ammonia, and not urea excretion was increased at pH 8.0, and that the elevation was proportional to a general increase in MO2. There was an accompanying elevation in net acidic equivalent excretion and/or basic equivalent uptake which occurred mainly at the gills. Net Na+ balance was little affected while Cl- balance became negative, implicating a disturbance of Cl- versus base exchange rather than Na+ versus acid exchange. Arterial blood pH increased by 0.2 units at pH 8.0, reflecting combined metabolic and respiratory alkaloses. Most parameters recovered to control levels by 18-24h after return to pH 6.0. With respect to large Tambaqui, we conclude that a physiology adapted to acidic pH performs inappropriately at moderately alkaline pH. In small Tambaqui (4-15g), the responses were very different, with an initial inhibition of ammonia excretion rate at pH 8.0 followed by a subsequent restoration of control levels. Elevated ammonia excretion rate occurred only after return to pH 6.0. Furthermore, MO2, plasma cortisol, and branchial vH+ATPase activities all declined during pH 8.0 exposure in small Tambaqui, in contrast to the responses in larger fish. Overall, small Tambaqui appear to cope better at pH 8.0, a difference that may correlate with their natural history in the wild.

Comparison of the effect of two different ways of cardiopulmonary resuscitation during cardiac arrest

Objective To compare the effect of two different types of cardiopulmonary resuscitation(CPR) in cardiac arrest. Methods 150 patients with cardiac arrest were selected.The patients were divided into two groups according to the random number table method, each group in 75cases.The patients in the control group were treated with CPR.The patients in the observation group were treated with CPR machine.The body temperature, hemoglobin concentration, hematocrit, arterial blood gas analysis and resuscitation were compared between the two groups after 10min and 30min. Results There were no statistically significant differences in body temperature, hemoglobin and hematocrit between the control group and the observation group at 10min and 30min after CPR (t10min=1.44, 2.01, 1.23, t30min=1.69, 1.81, 1.02, all P>0.05). There were no statistically significant differences in PaCO2 between the two groups at 10 min and 30 min after resuscitation (t=1.54, 1.02, all P>0.05). The arterial blood pH[(7.02±0.14)], PaO2[(16.29±4.38)kPa], HCO3- [(5.66±1.73)kPa]and SaO2[(0.84±0.05)%]of the control group recovered 30 min were significantly lower than recovered 10 min (t=7.14, 6.55, 6.20, 7.03, all P<0.05). The arterial blood pH[(7.11±0.1)], PaO2[(18.36±4.55)kPa], HCO3- [(6.34±2.15)kPa], SaO2[(0.86±0.04)%]of the observation group recovered 30 min were significantly lower than recovered 10 min (t=6.75, 6.21, 6.01, 6.60, all P<0.05). The arterial blood pH, PaO2, HCO3- and SaO2 of the observation group were significantly higher than those in the control group at 10 min and 30 min, the differences were statistically significant (t10min=6.03, 7.34, 7.88, 6.10, t30min=6.21, 8.20, 7.10, 6.11, all P<0.05). The effective rate of CPR in the observation group was 69.33%, which was significantly higher than 46.67% in the control group, the difference was statistically significant (χ2=9.34, P<0.05). Conclusion Compared with artificial heart and lung resuscitation, CPR machine is more effective for patients with heartbeat respiratory arrest.It is more effective in cycling support and can improve the efficacy of CPR and is worthy of clinical application. Key words: Heartbeat respiratory arrest; Cardiopulmonary resuscitation; Cardiopulmonary resuscitation machine

Study on the effect of mechanical compression and manual compression during cardiopulmonary resuscitation for cardiac arrest patients

Objective To analyze the effect of mechanical press and manual press in cardiopulmonary resuscitation. Methods A prospective randomized controlled study was performed. A total of 95 cases who needed cardiopulmonary resuscitation were collected, according to the inclusion criteria, which including mechanical compression group (n= 48), and the manual compression group (n=47). Demographic, clinical course of two groups were collected. Arterial and venous blood gas analysis in the recovery after the start of 5 minutes, 15 minutes, 30 minutes, the end of recovery were also collected and the pH value, partial pressure of oxygen, extracellular base remaining, actual bicarbonate, lactic acid, calcium and central venous oxygen saturation (ScvO2) and other data were mainly analyzed. All data collation and statistical analysis were used Microsoft excel, SAS 9.4. The enumeration data were expressed by the frequency and percentage, and chi square test was used. The measurement data were expressed by mean and standard deviation, and t test was used. Multiple Logistic regression analysis was performed to analysis of the effect of various factors. Results There were no statistically differences in age and pathogenic factors between the mechanical compression group and manual compression group (P>0.05). The press time, success rate of resuscitation and hospitalization days were respectively (22±14) minutes, 81%, (37±16) days in the mechanical compression group and (27±19) minutes, 54%, (41±20) days in the manual compression group, with no statistically significant differences (all P>0.05). Mechanical compression group and manual compression group were cured in 17 cases, 10 cases, survived in 21 cases, 9 cases, deaded in 10 cases, 28 cases, with statistically significant differences between 2 groups (P<0.05). The troponin Ⅰ and creatine kinase MB were respectively (4.1±2.0) ng/ml, (31±15) U/L in the manual compression group and (5.6±1.9) ng/ml, (43±22) U/L in the mechanical compression group, with statistically significant differences between 2 groups (P<0.05). The defibrillation energy and defibrillation times in manual group were significantly higher than that of mechanical compression group (P<0.05). Multivariate logistic regression analysis showed that the central venous oxygen saturation at the first 5 minutes after the start of compression (χ2=65.0538, P<0.0001), the arterial blood pH at the end of compression (χ2=21.5779, P<0.0001), and the 5% sodium bicarbonate was significantly correlated with the prognosis of survival after resuscitation, mechanical compression group was better than the manual compression group (χ2=3.1421, P=0.0463). Conclusions The effect of cardiopulmonary resuscitation machine is better than that of manual compression, which can effectively improve the clinical treatment effect. The result recommends the use of cardiopulmonary resuscitation machine for patients with cardiac arrest. Key words: Cardiopulmonary resuscitation; Prognosis; Automatic cardiopulmonary resuscitation machine; Mechanical compression; Manual compression; Cardiac arrest

A new method for noninvasive measurement of pulmonary gas exchange using expired gas

Measurement of the gas exchange efficiency of the lung is often required in the practice of pulmonary medicine and in other settings. The traditional standard is the values of the PO2, PCO2, and pH of arterial blood. However arterial puncture requires technical expertise, is invasive, uncomfortable for the patient, and expensive. Here we describe how the composition of expired gas can be used in conjunction with pulse oximetry to obtain useful measures of gas exchange efficiency. The new procedure is noninvasive, well tolerated by the patient, and takes only a few minutes. It could be particularly useful when repeated measurements of pulmonary gas exchange are required. One product of the procedure is the difference between the PO2 of end-tidal alveolar gas and the calculated PO2 of arterial blood. This measurement is related to the classical alveolar-arterial PO2 difference based on ideal alveolar gas. However that traditional index is heavily influenced by lung units with low ventilation-perfusion ratios, whereas the new index has a broader physiological basis because it includes contributions from the whole lung.

Characterization of Chronic Obstructive Pulmonary Disease Patients with a Long Length of Stay: A Retrospective Observational Cohort Study.

Chronic obstructive pulmonary disease (COPD) exacerbation is one of the most common reasons for hospital admission. Patients with COPD with a long length of stay (LoS) occupy a disproportionately high fraction of hospital bed-days. The objective of this study was to identify associations of long LoS in patients admitted with COPD exacerbation. From December 2012 until June 2013, 499 patients were admitted to Queens Hospital, Romford, UK, with COPD exacerbation. Mean LoS was 7 days, with a median of 5 days, and a 90th percentile of 14 days. In this retrospective observational cohort study, 64 patients with a short LoS were compared with 62 patients with a long LoS. Relative to the short LoS, patients with long LoS had significantly lower arterial blood pH, higher arterial PaCO2 and HCO3, higher white cell count, higher globulin and more frequent chest X-ray changes, lower albumin levels, and lower Barthel and Braden scores. They were less likely to have seen the hospital COPD specialist nurse, more likely to require escalation of social care on discharge, and more likely to die during admission. Nearly 66% of the long LoS patients remained in hospital beyond the time of being medically fit for discharge. Commonly cited reasons for delayed discharge were the wait for therapy and social services assessments and the wait for commencement of community social care. Meticulous targeting of features peculiar to long LoS patients has the potential to reduce future hospital bed-days for patients with COPD in our and other hospitals.

Outcome of vaginal birth after cesarean section in women with advanced maternal age

Objective: To explore the perinatal outcome of vaginal birth after cesarean (VBAC) in women with advanced age. Methods: Totally 2 587 women delivered after one or two prior cesarean sections (gestational age≥28 weeks) in the First Affiliated Hospital of Kunming Medical University from July 2013 to February 2017. 909 trial of labor after cesarean(TOLAC) cases of singleton pregnancy with one prior cesarean section were studied retrospectively. According to the age, of the 909 TOLAC cases, 237 were the advanced age group, and 672 cases were the low age group. The maternal and neonatal outcomes between the two groups were compared. Results: The percentage of TOLAC in women with advanced age was 32.4% (237/731), and VBAC rate was 88.2% (209/237). The percentage of TOLAC in younger women was 36.2% (672/1 856), and VBAC rate was 82.4% (554/672). The difference of the TOLAC rate between the two groups was not significant (P>0.05), and the VBAC rate of the advanced age group was higher than the low age group (P<0.05). In the comparison of the two groups, the proportion of bachelor degree or above(55.7%,132/237), the prepregnancy BMI (22.4±3.0) kg/m(2), pregnant interval time (68.5±38.3) months, the proportion of gestational hypertension (8.4%,20/237), the proportion of gestational diabetes(34.6%,82/237) and the rate of the neonatal ICU admission (18.1%,43/237) in the advanced age group were higher than those of the low age group (P<0.05), respectively. And there were no significant differences in the rate of postpartum hemorrhage, the rate of postpartum hemorrhage≥1 500 ml, the rate of postpartum transfusion, puerperal morbidity, neonatal birth weight, neonatal 5 min Apgar score<7 score, umbilical artery blood pH<7.0, neonatal tracheal intubation and respiratory distress syndrome (all P>0.05). In all TOLAC cases, the rate of uterine rupture was 0.11%(1/909) and there was no maternal and neonatal death. Conclusion: VBAC is a safe and feasible way of delivery for singleton pregnancy after one prior cesarean section in women with advanced age.

Association Between Acidosis Soon After Reperfusion and Contrast-Induced Nephropathy in Patients With a First-Time ST-Segment Elevation Myocardial Infarction.

BackgroundContrast‐induced nephropathy (CIN) is associated with poor outcomes in patients with acute myocardial infarction. However, the predictors of CIN have yet to be fully elucidated.Methods and ResultsThe study included 273 consecutive patients with a first‐time ST‐segment elevation myocardial infarction who underwent reperfusion within 12 hours of symptom onset. The exclusion criteria were hemodialysis, mechanical ventilation, or previous coronary artery bypass grafting. All patients underwent arterial blood gas analysis soon after reperfusion. CIN was defined as an increase of 0.5 mg/dL in serum creatinine or a 25% increase from baseline between 48 and 72 hours after contrast medium exposure. Acidosis was defined as an arterial blood pH <7.35. CIN was observed in 35 patients (12.8%). Multivariable logistic regression analysis with forward stepwise algorithm revealed a significant association between CIN and the following: reperfusion time, the prevalence of hypertension, peak creatine kinase‐MB, high‐sensitivity C‐reactive protein on admission, and the incidence of acidosis (P<0.05). Multivariable logistic regression analysis revealed that the incidence of acidosis was associated with CIN when adjusted for age, male sex, body mass index, amount of contrast medium used, estimated glomerular filtration rate on admission, glucose level on admission, high‐sensitivity C‐reactive protein on admission, and left ventricular ejection fraction (P<0.05). Moreover, the incidence of acidosis was associated with CIN when adjusted for the Mehran CIN risk score (odds ratio: 2.229, P=0.049).ConclusionsThe incidence of acidosis soon after reperfusion was associated with CIN in patients with a first‐time ST‐segment elevation myocardial infarction.

Lethal avian influenza A (H5N1) virus induces ataxic breathing in mice with apoptosis of pre-Botzinger complex neurons expressing neurokinin-1 receptor.

Lethal influenza A (H5N1) induces respiratory failure in humans. Although it also causes death at 7 days postinfection (dpi) in mice, the development of the respiratory failure and the viral impact on pre-Botzinger complex (PBC) neurons expressing neurokinin 1 receptor (NK1R), which is the respiratory rhythm generator, have not been explored. Body temperature, weight, ventilation, and arterial blood pH and gases were measured at 0, 2, 4, and 6 dpi in control, lethal HK483, and nonlethal HK486 viral-infected mice. Immunoreactivities (IR) of PBC NK1R, H5N1 viral nucleoprotein (NP), and active caspase-3 (CASP3; a marker for apoptosis) were detected at 6 dpi. HK483, but not HK486, mice showed the following abnormalities: 1) gradual body weight loss and hypothermia; 2) tachypnea at 2-4 dpi and ataxic breathing with long-lasting apneas and hypercapnic hypoxemia at 6 dpi; and 3) viral replication in PBC NK1R neurons with NK1R-IR reduced by 75% and CASP3-IR colabeled at 6 dpi. Lethal H5N1 viral infection causes tachypnea at the early stage and ataxic breathing and apneas (hypercapnic hypoxemia) leading to death at the late stage. Its replication in the PBC induces apoptosis of local NK1R neurons, contributing to ataxic breathing and respiratory failure.

Intermittent versus continuous renal replacement therapy in acute methanol poisoning: comparison of clinical effectiveness in mass poisoning outbreaks

BackgroundIntermittent hemodialysis (IHD) is the modality of choice in the extracorporeal treatment (ECTR) of acute methanol poisoning. However, the comparative clinical effectiveness of intermittent versus continuous modalities (CRRT) is unknown. During an outbreak of mass methanol poisoning, we therefore studied the effect of IHD versus CRRT on mortality and the prevalence of visual/central nervous system (CNS) sequelae in survivors.MethodsThe study was designed as prospective observational cohort study. Patients hospitalized with a diagnosis of acute methanol poisoning were identified for the study. Exploratory factor analysis and multivariate logistic regression were applied to determine the effect of ECTR modality on the outcome.ResultsData were obtained from 41 patients treated with IHD and 40 patients with CRRT. The follow-up time in survivors was two years. Both groups of patients were comparable by age, time to presentation, laboratory data, clinical features, and other treatment applied. The CRRT group was more acidemic (arterial blood pH 6.96 ± 0.08 vs. 7.17 ± 0.07; p < 0.001) and more severely poisoned (25/40 vs. 9/41 patients with Glasgow Coma Scale (GCS) ≤ 8; p < 0.001). The median intensive care unit length of stay (4 (range 1–16) days vs. 4 (1–22) days; p = 0.703) and the number of patients with complications during the treatment (11/41 vs. 13/40 patients; p = 0.576) did not differ between the groups. The mortality was higher in the CRRT group (15/40 vs. 5/41; p = 0.008). The number of survivors without sequelae of poisoning was higher in the IHD group (23/41 vs. 10/40; p = 0.004). There was a significant association of ECTR modality with both mortality and the number of survivors with visual and CNS sequelae of poisoning, but this association was not present after adjustment for arterial blood pH and GCS on admission (all p > 0.05).ConclusionsIn spite of the faster correction of the acidosis and the quicker removal of the toxic metabolite in intermittent dialysis, we did not find significant differences in the treatment outcomes between the two groups after adjusting for the degree of acidemia and the severity of poisoning on admission. These findings support the strategy of “use what you have” in situations with large outbreaks and limited dialysis capacity.