Arterial PaO2 Research Articles

Physiological control of respiration

Respiration involves the inward and outward movement of air into the lungs. This process facilitates gaseous exchange. The rate of respiration therefore regulates the partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) in the blood. Spontaneous respiration occurs as a result of rhythmic discharge of motor neurons innervating respiratory muscles. Nerve impulses from the brain are responsible for this rhythmic discharge. The rhythmic contraction and relaxation of respiratory muscles alternatively fill the lungs during inspiration and empty them in expiration. This rhythmic discharges from the brain are regulated by changes in arterial PaO2, PaCO2 and hydrogen ion (H+) concentration, which is called the chemical control of respiration.

Hyperoxemia and Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage.

Cerebral vasospasm is a major contributor to disability and mortality after aneurysmal subarachnoid hemorrhage. Oxidation of cell-free hemoglobin plays an integral role in neuroinflammation and is a suggested source of tissue injury after aneurysm rupture. This study sought to determine whether patients with subarachnoid hemorrhage and cerebral vasospasm were more likely to have been exposed to early hyperoxemia than those without vasospasm. This single-center retrospective cohort study included adult patients presenting with aneurysmal subarachnoid hemorrhage to Vanderbilt University Medical Center between January 2007 and December 2017. Patients with an ICD-9/10 diagnosis of aneurysmal subarachnoid hemorrhage were initially identified (N = 441) and subsequently excluded if they did not have intracranial imaging, arterial PaO2 values or died within 96h post-rupture (N = 96). The final cohort was 345 subjects. The degree of hyperoxemia was defined by the highest PaO2 measured within 72h after aneurysmal rupture. The primary outcome was development of cerebral vasospasm, which included asymptomatic vasospasm and delayed cerebral ischemia (DCI). Secondary outcomes were mortality and modified Rankin Scale. Three hundred and forty five patients met inclusion criteria; 218 patients (63%) developed vasospasm. Of those that developed vasospasm, 85 were diagnosed with delayed cerebral ischemia (DCI, 39%). The average patient age of the cohort was 55 ± 13years, and 68% were female. Ninety percent presented with Fisher grade 3 or 4 hemorrhage (N = 310), while 42% presented as Hunt-Hess grade 4 or 5 (N = 146). In univariable analysis, patients exposed to higher levels of PaO2 by quintile of exposure had a higher mortality rate and were more likely to develop vasospasm in a dose-dependent fashion (P = 0.015 and P = 0.019, respectively). There were no statistically significant predictors that differentiated asymptomatic vasospasm from DCI and no significant difference in maximum PaO2 between these two groups. In multivariable analysis, early hyperoxemia was independently associated with vasospasm (OR = 1.15 per 50mmHg increase in PaO2 [1.03, 1.28]; P = 0.013), but not mortality (OR = 1.10 [0.97, 1.25]; P = 0.147) following subarachnoid hemorrhage. Hyperoxemia within 72h post-aneurysmal rupture is an independent predictor of cerebral vasospasm, but not mortality in subarachnoid hemorrhage. Hyperoxemia is a variable that can be readily controlled by adjusting the delivered FiO2 and may represent a modifiable risk factor for vasospasm.

How Do We Monitor Oxygenation during the Management of PPHN? Alveolar, Arterial, Mixed Venous Oxygen Tension or Peripheral Saturation?

Oxygen is a pulmonary vasodilator and plays an important role in mediating circulatory transition from fetal to postnatal period. Oxygen tension (PO2) in the alveolus (PAO2) and pulmonary artery (PaO2) are the main factors that influence hypoxic pulmonary vasoconstriction (HPV). Inability to achieve adequate pulmonary vasodilation at birth leads to persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen therapy is the mainstay of PPHN management. However, optimal monitoring and targeting of oxygenation to achieve low pulmonary vascular resistance (PVR) and optimizing oxygen delivery to vital organs remains unknown. Noninvasive pulse oximetry measures peripheral saturations (SpO2) and a target range of 91–95% are recommended during acute PPHN management. However, for a given SpO2, there is wide variability in arterial PaO2, especially with variations in hemoglobin type (HbF or HbA due to transfusions), pH and body temperature. This review evaluates the role of alveolar, preductal, postductal, mixed venous PO2, and SpO2 in the management of PPHN. Translational and clinical studies suggest maintaining a PaO2 of 50–80 mmHg decreases PVR and augments pulmonary vasodilator management. Nevertheless, there are no randomized clinical trials evaluating outcomes in PPHN targeting SpO2 or PO2. Also, most critically ill patients have umbilical arterial catheters and postductal PaO2 may not be an accurate assessment of oxygen delivery to vital organs or factors influencing HPV. The mixed venous oxygen tension from umbilical venous catheter blood gas may assess pulmonary arterial PO2 and potentially predict HPV. It is crucial to conduct randomized controlled studies with different PO2/SpO2 target ranges for the management of PPHN and compare outcomes.

A randomised dose-response study of prophylactic Methoxamine infusion for preventing spinal-induced hypotension during Cesarean delivery

Backgroundα-receptor agonists have been reported to be safe and effective for treating or preventing spinal-induced hypotension during cesarean delivery. As a pure α1 adrenergic agonist, methoxamine has potential advantages of reducing myocardial oxygen consumption and protecting the heart in obstetric patients compared to phenylephrine. The aim of this study was to determine the optimal prophylactic methoxamine infusion dose that would be effective for preventing spinal-induced hypotension in 50% (ED50) and 95% (ED95) of parturients.MethodsEighty parturients with a singleton pregnancy scheduled for elective cesarean delivery were randomly allocated to receive prophylactic methoxamine infusion at one of four different fixed-rates: 1 μg/kg/min (group M1), 2 μg/kg/min (group M2), 3 μg/kg/min (group M3), or 4 μg/kg/min (group M4). An adequate response was defined as absence of hypotension (maternal SBP < 80% of baseline or SBP < 90 mmHg). The values for ED50 and ED95 of prophylactic methoxamine infusion were determined by probit regression model. The outcomes of maternal hemodynamics and fetal status were compared among the groups.ResultsThe calculated ED50 and ED95 (95% confidence interval) of prophylactic methoxamine infusion dose were 2.178 (95% CI 1.564 to 2.680) μg/kg/min and 4.821 (95% CI 3.951 to 7.017) μg/kg/min, respectively. The incidence of hypotension decreased with increasing methoxamine infusion dose (15/20, 11/20, 7/20 and 2/20 in group M1, M2, M3 and M4 respectively, P < 0.001). 1-min Apgar scores and umbilical arterial PaO2 were lower but umbilical arterial PaCO2 was higher in Group M1. No difference was found in the other incidence of adverse effects and neonatal outcomes among groups.ConclusionsUnder the conditions of this study, when prophylactic methoxamine infusion was given at a fixed-rate based on body weight for preventing spinal-induced hypotension in obstetric patients, the values for ED50 and ED95 were 2.178 μg/kg/min and 4.821 μg/kg/min respectively.Clinical trial registrationChinese Clinical Trial Registry (ChiCTR), registry number of clinical trial: ChiCTR-1,800,018,988, date of registration: October 20, 2018.

Pulse Oximetry in Comparison to Arterial Blood Oxygen Saturation in Patients with Respiratory Distress in Neonatal Intensive Care Unit (NICU)

Background: It is essential to monitor the saturation of oxygen in newborns receiving supplemental oxygen to reduce the incidence of exposure to hyperoxemia and their potential hazardous effects of radical oxygen species. The oxygen saturation is measured by pulse oximeter which is a non-invasive tool. Arterial blood gas is used to determine the pH, PaCO2, PaO2 and the bicarbonate level. Aims and Objectives: This study aimed at searching the reliability of non-invasive pulse oximeter in knowing oxygen saturation (SpO2) in comparison with arterial blood PaO2 in neonates with respiratory distress. The primary objective was to correlate the values between partial pressure of oxygen (PaO2) and pulse oxygen saturation by pulse oximeter (SpO2).The secondary objectives were 1) To find out the efficacy of pulse oximeter in diagnosing hypoxia in comparison with PaO2. 2) To find out efficacy of pulse oximeter in diagnosing hyperoxemia in comparison with PaO2. Material and Method: Observational study was conducted on thirty neonates suffering from different causes of respiratory distress in NICU of Krishna Hospital, Karad during December 2017 to September The PaO2 measurements were obtained from the blood analyzer; simultaneous pulse oxygen saturation were recorded. Results: A significant correlation was observed between values of pulse oxygen saturation by pulse oximeter (SpO2) and partial pressure of oxygen (PaO2) by arterial blood sampling (r value -0.73, p<0.01) On ROC curve analysis, sensitivity and specificity of pulse oximetry in prediction of hypoxemia was 87.5% and 85.7% at cut-off of 90% and 91% each. The sensitivity and specificity of pulse oximetry in prediction of hyperoxemia was 100% and 71.4% at cuff-off of 94% while it was 88.9% and 76.2% at cut-off of 95% respectively. Conclusion: Pulse oximetry showed a good correlation with arterial blood PaO2. Oxygen saturation measured by pulse oximetry is a good diagnostic and prognostic tool for detecting hypoxemia and hyperoxemia.

The association between post-cardiac arrest cerebral oxygenation and survival with favorable neurological outcomes: A multicenter study

ObjectiveCerebral oximetry is a non-invasive system that uses near infrared spectroscopy to measure regional cerebral oxygenation (rSO2) in the frontal lobe of the brain. Post-cardiac arrest rSO2 may be associated with survival and neurological outcomes in out-of-hospital cardiac arrest patients; however, no studies have examined relationships between rSO2 and neurological outcomes following in-hospital cardiac arrest (IHCA). We tested the hypothesis that rSO2 following IHCA is associated with survival and favorable neurological outcomes. DesignProspective study from nine acute care hospital in the United States and United Kingdom. PatientsConvenience sample of IHCA patients admitted to the intensive care unit with post-cardiac arrest syndrome. InterventionsCerebral oximetry monitoring (Equanox 7600, Nonin Medical, MN, USA) during the first 48 h after IHCA. Measurements and Main ResultsSubject’s rSO2 was calculated as the mean of collected data at different time intervals: hourly between 1−6 h, 6−12 h, 12−18 h, 18−24 h and 24−48 h. Demographic data pertaining to possible confounding variables for rSO2 and primary outcome were collected. The primary outcome was survival with favorable neurological outcomes (cerebral performance scale [CPC] 1−2) vs severe neurological injury or death (CPC 3−5) at hospital discharge. Univariate and multivariate statistical analyses were performed to correlate cerebral oximetry values and other variables with the primary outcome. Among 87 studied patients, 26 (29.9%) achieved CPC 1−2. A significant difference in mean rSO2 was observed during hours 1−2 after IHCA in CPC 1−2 vs CPC 3−5 (73.08 vs. 66.59, p = 0.031) but not at other time intervals. There were no differences in age, Charlson comorbidity index, APACHE II scores, CPR duration, mean arterial pressure, PaO2, PaCO2, and hemoglobin levels between two groups. ConclusionsThere may be a significant physiological difference in rSO2 in the first two hours after ROSC in IHCA patients who achieve favorable neurological outcomes, however, this difference may not be clinically significant.

Volume-associated hemodynamic variables for prediction of cardiac surgery-associated acute kidney injury

Delayed diagnosis of acute kidney injury (AKI) is common because the changes in renal function markers often lag injury. We aimed to find optimal non-invasive hemodynamic variables for the prediction of postoperative AKI and AKI renal replacement therapy (RRT). The data were collected from 1,180 patients who underwent cardiac surgery in our hospital between March 2015 and Feb 2016. Postoperative central venous pressure (CVP), mean arterial pressure (MAP), heart rate, PaO2, and PaCO2 on ICU admission and daily fluid input and output (calculated as 24 h PFO) were monitored and compared between AKI vs. non-AKI and RRT vs non-RRT cases. The AKI and AKI-RRT incidences were 36.7% (n = 433) and 1.2% (n = 14). Low cardiac output syndromes (LCOSs) occurred significantly more in AKI and RRT than in non-AKI or non-RRT groups (13.2% vs. 3.9%, P < 0.01; 42.9% vs. 7.1%, P < 0.01). CVP on ICU admission was significantly higher in AKI and RRT than in non-AKI and non-RRT groups (11.5 vs. 9.0 mmHg, P < 0.01; 13.3 vs. 9.9 mmHg, P < 0.01). 24 h PFO in AKI and RRT cases were significantly higher than in non-AKI or non-RRT patients (1.6% vs. 0.9%, P < 0.01; 3.9% vs. 0.8%, P < 0.01). The areas under the ROC curves to predict postoperative AKI by CVP on ICU admission (> 11 mmHg) + LCOS + 24 h PFO (> 5%) and to predict AKI-RRT by CVP on ICU admission (> 13 mmHg) + LCOS + 24 h PFO (> 5%) were 0.763 and 0.886, respectively. The volume-associated hemodynamic variables, including CVP on ICU admission, LCOS, and 24 h PFO after surgery could predict postoperative AKI and AKI-RRT.

Extracorporeal Life Support Organization (ELSO): Guidelines for Neonatal Respiratory Failure.

Extracorporeal Life Support Organization (ELSO): Guidelines for Neonatal Respiratory Failure.

Accuracy of pulse oximetry in preterm and term infants is insufficient to determine arterial oxygen saturation and tension.

Oxygen saturation is frequently monitored with pulse oximetry to assess vital signs in critically ill patients. Optimally, pulse oximetry closely tracks arterial oxygen tension (PaO2 ), which provides guidance in oxygen titration. We investigated whether monitoring peripheral oxygen saturation (SpO2 ) could accurately guide oxygen titration in newborn infants. Twenty seven thousand two hundred thirty seven SpO2 readings were retrospectively paired with arterial oxygen saturation (SaO2 ) and PaO2 results from blood gas analyses performed in infants with arterial catheters in place. SpO2 overestimated SaO2 readings by 2.9±5.8%. When pulse oximetry readings were within the defined oxygen saturation target range, 7809 (20.9%) SaO2 values were below and 2830 (7.6%) exceeded the target range. In 57% of patients, PaO2 levels<6kPa was diagnosed while SpO2 readings were>90%. PaO2 >11kPa was recorded in 19% of cases, when SpO2 readings were<95%. Infants treated with supplemental oxygen showed a threefold increased risk of hypoxaemia compared to infants breathing room air. Sensitivity and specificity for detecting upper and lower target range limits were fair to good. For SpO2 values below 91%, ISO quality criteria were no longer fulfilled. Based on arterial blood gas analyses as reference, pulse oximetry readings did not fulfil the performance requirements for titrating oxygen in neonatal patients.

Effect of Intravenous Interferon β-1a on Death and Days Free From Mechanical Ventilation Among Patients With Moderate to Severe Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is associated with high mortality. Interferon (IFN) β-1a may prevent the underlying event of vascular leakage. To determine the efficacy and adverse events of IFN-β-1a in patients with moderate to severe ARDS. Multicenter, randomized, double-blind, parallel-group trial conducted at 74 intensive care units in 8 European countries (December 2015-December 2017) that included 301 adults with moderate to severe ARDS according to the Berlin definition. The radiological and partial pressure of oxygen, arterial (Pao2)/fraction of inspired oxygen (Fio2) criteria for ARDS had to be met within a 24-hour period, and the administration of the first dose of the study drug had to occur within 48 hours of the diagnosis of ARDS. The last patient visit was on March 6, 2018. Patients were randomized to receive an intravenous injection of 10 μg of IFN-β-1a (144 patients) or placebo (152 patients) once daily for 6 days. The primary outcome was a score combining death and number of ventilator-free days at day 28 (score ranged from -1 for death to 27 if the patient was off ventilator on the first day). There were 16 secondary outcomes, including 28-day mortality, which were tested hierarchically to control type I error. Among 301 patients who were randomized (mean age, 58 years; 103 women [34.2%]), 296 (98.3%) completed the trial and were included in the primary analysis. At 28 days, the median composite score of death and number of ventilator-free days at day 28 was 10 days (interquartile range, -1 to 20) in the IFN-β-1a group and 8.5 days (interquartile range, 0 to 20) in the placebo group (P = .82). There was no significant difference in 28-day mortality between the IFN-β-1a vs placebo groups (26.4% vs 23.0%; difference, 3.4% [95% CI, -8.1% to 14.8%]; P = .53). Seventy-four patients (25.0%) experienced adverse events considered to be related to treatment during the study (41 patients [28.5%] in the IFN-β-1a group and 33 [21.7%] in the placebo group). Among adults with moderate or severe ARDS, intravenous IFN-β-1a administered for 6 days, compared with placebo, resulted in no significant difference in a composite score that included death and number of ventilator-free days over 28 days. These results do not support the use of IFN-β-1a in the management of ARDS. ClinicalTrials.gov Identifier: NCT02622724.

Prevalence of Sensorineural Hearing Loss in Children with Palliated or Repaired Congenital Heart Disease.

BackgroundChildren with congenital heart disease (CHD) are at increased risk of neurodevelopmental deficits, and the presence of sensorineural hearing loss (SNHL) may further lead to poor language skills acquisition and speech delays. Prevalence of SNHL in the general pediatric population is estimated to be 0.2% at birth to 0.35% during adolescence. Very few studies have attempted to estimate SNHL prevalence in children who have undergone congenital heart surgery.MethodsThis retrospective study aimed to estimate SNHL prevalence in children who underwent congenital heart surgery in our institution and were followed up in our high-risk pediatric cardiology clinics for four years from 2009 to 2013. Data were collected on demographics, preoperative variables, surgical variables, and post-operative variables.ResultsSNHL prevalence in asymptomatic, palliated/repaired CHD patients followed in our high-risk clinics and undergoing routine surveillance was 11.6% (20 of 172 patients with hearing impairment). SNHL prevalence was not statistically higher in single-ventricle patients (17.2%) compared to biventricular patients (14.7%). Inotropic score in the first 24 hours of postoperative period (p=0.05), lowest arterial PaO2 (p=0.003), duration of Lasix drip (p=0), and bolus dose in days (p=0.03) were all found to be statistically significant in the hearing-impaired group. However, using logistic regression, we identified no statistically significant predictors for hearing loss.ConclusionThe results suggest the need for routine audiology screening of all patients with complex CHD, especially those who have undergone neonatal cardiac repair/palliation at less than one year of age, irrespective of risk factors.

Azaperone and xylazine: A pharmacological combination to facilitate captive deer management for red brocket deer (Mazama americana).

The care and management of deer in captivity is challenging, especially in the case of red brocket deer (Mazama americana), whose routine management using physical restraint is difficult. Our study evaluated the effects of azaperone and xylazine combination for immobilizing red brocket deer and allow for the standard capture and handling protocols (e.g., biological material, horn cutting, and trimming) to be conducted safely. Six adult, captive, red brocket deer received an intramuscular injection of either 1 mg/kg azaperone and 0.5 mg/kg xylazine (AX0.5) or 1 mg/kg azaperone and 1 mg/kg xylazine (AX1.0). Sedation latency, sternal recumbency, safe handling, and quality of the sedation were evaluated to provide an overview of how the immobilizing drugs affected managing the species in captivity. Additionally, heart rate, respiratory rate, mean arterial pressure, rectal temperature, pH, PaO2, PaCO2, SaO2, HCO3-, BE, Na+, K+ and serum lactate were also measured. The latency period of the animals in the AX0.5 group was greater than that of the animals in the AX1.0 group (7 ± 6.6 min vs. 5 ± 2.0 min), as was the time for them to assume sternal recumbency (12 ± 9.7 min vs. 6 ± 3.1 min). However, the time after the initial dose at which the animals could safely be handled (14 ± 4.5 min vs. 12 ± 5.2 min), and the time until the end of the safe handling period (75 ± 12.3 min vs. 85 ± 6.8 min) were similar for both groups. Animals in both groups showed physiological stability during all evaluations, but hypoxemia was observed in one animal in each group. We conclude that both drug combinations are safe and effective at sedating red brocket deer in captivity and suggest that the procedure be performed with oxygen supplementation to reduce the potential for hypoxia.

Comparison of three natural surfactants according to lung ultrasonography scores in newborns with respiratory distress syndrome

Introduction Lung ultrasonography (LUS) is a noninvasive bed-side test and increasingly used by clinicians in the management and follow-up of respiratory distress syndrome (RDS) in premature infants. Objective To compare the results of three natural surfactants according to LUS scores in premature infants with RDS. Methods This was a prospective study on 62 preterm infants (25–34 weeks) with RDS and receiving surfactant according to 2016 European guidelines. All patients underwent a clinical evaluation and chest X-ray at three study points; at the first hours of life (presurfactant), and at 6–12th hour (early postsurfactant) and 24th hour (late postsurfactant) of surfactant. Simultaneously fractional inspired oxygen (FiO2) need, arterial PaO2 values, Downes and LUS scores were noted. The patients were randomized into three groups; Group 1 (n = 23), poractant alpha; Group 2 (n = 20), beractant; and Group 3 (n = 19), calfactant. The groups were compared according to clinical, laboratory and radiological variables as well as LUS scores. Results Gestational age (p = .05), birthweight (p = .07), and SNAPPE-II scores (p = .57) were similar in three groups. Repeated dose need was the highest in Group 3 (p = .04). FiO2 need (p = .04) was the highest and PaO2 values (p = .03) were the lowest at late postsurfactant point in the same group. LUS scores were also the highest in Group 3 at this period (p = .02). Downes scores were similar in groups at all points (p > .05). NICU stay were similar in groups (p = .53). The durations of total oxygen supplementation, mechanical ventilation, and hospital stay were the same in groups (p > .05). Conclusions In newborns with RDS, poractant alpha and beractant have similarly reduced oxygen need in accordance to the LUS findings. However, they seem to be superior compared to calfactant.

ASSESSMENT OF INFERIOR VENA CAVA DIAMETER MEASURED BY ULTRA-SONOGRAPHY IN CORRELATION WITH CENTRAL VENOUS PRESSURE VALUE IN PATIENTS WITH SEPSIS

Background: Bedside ultrasound is potentially a useful noninvasive adjunct to estimate the intravascular volume status in sepsis. Aim of the work: Evaluating the correlation between inferior vena cava diameter measured non-invasively with ultrasonography versus central venous pressure in assessment of intravascular volume status in patients with sepsis.Patients and methods: The study was conducted on sixty patients with sepsis (30 ventilated and 30 non-ventilated) in the Respiratory Intensive Care Unit at Abbassia Chest Hospital from January 2018 to September 2018. For all included patients demographic data were collected Recording vital sings, mean arterial pressure and Pao2/ Fio2were done. Laboratory investigation including complete blood count, serum lactic acid, arterial blood gas, quantitative C-reactiveprotein were also done. Sequential Organ Failure Assessment score (SOFA), Qsofa and Acute Physiology And Chronic Health Evaluation II score (APACHE II) were recorded. Finally measurement of IVC, CVP and intra-abdominal pressure were done Results: Males represent 75%while female were 25%withmean age of (47.40±14.49) years. The mean CVP was 12.48±3.78 cmH2O with an IVC maximum diameter of 17.95±3.28 mm and collapsibility index of 50.55±11.83 %. There was statistically significant positive correlation between CVP and IVC dmax and statistically significant negativecorrelation between CVP and IVC CI (%)in both ventilated and non ventilated groups. Also, CVP and IVC dmax were significantly correlated with outcome in both ventilated and non ventilated patients. The higher values of CVP and IVC dmax and the lower the value of IVC CI, the higher rates of mortality. Conclusion: US assessment of IVC diameter and caval index are simple and non invasive methods to assess intravascular volume status.

Intensivists Performed Percutaneous Bicaval Double-Lumen Echo-Guided Extracorporeal Membrane Oxygenation Cannulation at Bedside in Newborns and Children: A Retrospective Analysis.

To describe a single institution experience on echo-guided percutaneous bicaval double lumen extracorporeal membrane oxygenation cannulation performed at the bedside by intensivists. Retrospective observational study. Extracorporeal membrane oxygenation team of a tertiary care children's hospital. All patients 0-14 years old undergoing venovenous extracorporeal membrane oxygenation from January 1, 2013, to January 1, 2018. None. Thirty children underwent 32 extracorporeal membrane oxygenation runs. Median age at enrollment was 2 months (interquartile range, 0-20.5 mo), 65.6% of the runs (21 patients) were performed in newborns (n = 13, 40.6%) or infants (n = 8, 25%). Median preextracorporeal membrane oxygenation index was 66.9 (interquartile range, 50-85.6). Major comorbidities were present in 50% of patients. All patients were cannulated percutaneously. In two cases cannulation occurred from the left internal jugular vein. Extracorporeal membrane oxygenation was effective in increasing pH, arterial oxygen saturation, PaO2, and lowering PaCO2. The overall differences in pre and postextracorporeal membrane oxygenation values were statistically significant, while stratifying patients according to the cannula diameter (mm)/major diameter of the cannulated internal jugular vein (mm) ratio (> 0.67 or ≤ 0.67), statistical significance was reached only for the highest ratio. Complications were observed in three runs: two cannula tip dislocations in the right atrium and one limited flow in the only case in which an Avalon cannula was not used. In 20 cases (62.5% of 32 runs), the cannulated vessel was patent at follow-up or autopsy. A ratio less than or equal to 0.67 or greater than 0.67 did not influence the occurrence rate of complications, nonpatency of the internal jugular vein, death for intracranial bleeding and death at 30 days from extracorporeal membrane oxygenation discontinuation. Overall cumulative survival at 30 days from extracorporeal membrane oxygenation discontinuation was 60% (95% CI, 40-75), with a survival advantage in the case of ratio greater than 0.67 (65%; 95% CI, 44-80 vs 25%; 95% CI, 0-60). The described technique proved to be feasible, safe, and effective. Further investigation is needed.

Effectiveness of triple inhalation therapy and non-invasive ventilation in the treatment of acute exacerbated chronic obstructive pulmonary disease

Purpose : To determine the clinical effectiveness of combining triple inhalation therapy with noninvasive ventilation in treating acute exacerbated chronic obstructive pulmonary disease (AECOPD). Methods : A total of 128 AECOPD patients admitted in the Department of Respiratory Medicine of our Hospital were involved in the study. Two groups of patients were used (64 patients per group). The study group was given triple inhalation therapy and non-invasive ventilation, while only non-invasive ventilation was given to the control group. The curative effects of the two treatments and their effects on arterial Pa CO2 (partial pressure of carbon dioxide), pH and Pa O2 (partial pressure of oxygen) were determined. Results : The study group showed significantly higher treatment effectiveness than the control group (p < 0.05). Post-treatment Pa CO2 , pH, Pa O2 , respiratory rate and heart rate differed significantly between the two groups (p < 0.05). Improvements in the five indices were more in the study group than in the control group (p < 0.05). Conclusion : Combining triple inhalation therapy with non-invasive ventilation in the treatment of AECOPD enhances therapeutic effect, improves pulmonary ventilation, and reduces side effects. Keywords : Chronic obstructive pulmonary disease, Acute exacerbation, Triple inhalation, Non-invasive ventilation

Safety of apnea testing for the diagnosis of brain death: a comprehensive study on neuromonitoring data and blood gas analysis.

Here, we studied the safety of apnea testing (AT) for the determination of brain death with regard to intracranial pressure (ICP), cerebral perfusion and arterial blood gas parameters. We hypothesized that ICP only increases when cerebral perfusion pressure (CPP) remains positive during AT. A total of 34 patients who fulfilled brain death criteria were identified by chart review (2009-2017). We analysed ICP, CPP and mean arterial pressure (MAP) prior to AT, during AT and after AT, as well as arterial pH, paCO2 , paO2 and arterial O2 saturation at the start and end of AT. Intracranial pressure was 87.9±17.7mmHg (mean±SD) prior to AT, 89.9±17.2mmHg during AT and 86.4±15.2mmHg after AT (P=0.9). CPP was -6.9±12.8mmHg prior to AT, -7.1±13.7mmHg during AT and -8.6±13.0mmHg after AT (P=0.98), respectively. MAP was 82.9±14.6mmHg prior to AT, 84.7±13.9mmHg during AT and 79.7±9.6mmHg after AT (P=0.57), respectively. A total of 10 patients had positive CPP (8.6±4.3mmHg), but ICP did not increase during AT. Arterial pH decreased from 7.43±0.06 to 7.22±0.06 (P<0.05), paCO2 increased from 38.6±4.2 to 69.6±8.0mmHg (P<0.05), paO2 decreased from 416.3±113.4 to 289.2±146.5mmHg (P<0.05), and O2 saturation was stable at 99.8±0.4% and 98.2±3.2% (P=0.39). Apnea testing had no detrimental effect on ICP, CPP, MAP or oxygenation, regardless of the presence of an initially positive CPP. The lack of further ICP elevations is presumably explained by critical closing pressures above individual CPP levels during AT.

Protective effect of diallyl trisulfide on acute lung injury in rats

Objective Observing the protective effect of diallyl trisulfide (DATS) on acute lung injury induced by cecal ligation and puncture (CLP). Methods The animal model of acute lung injury was induced by CLP. The 30 male SD rats were fasted 16 h before surgery, then was anesthetized by intraperitoneal injection of 10% chloral hydrate (4 ml/kg). Then all rats were randomly divided into 3 groups (n=10), sham group (group Ⅰ), CLP+normal saline (NS) group (groupⅡ) and CLP+DATS group (group Ⅲ). Rats in groupⅠ and group Ⅱ were injected with saline 10 ml/kg through caudal vein, but group Ⅲ were injected with DATS 10 mg/kg. The arterial cannulation was used in carotid artery of the rat to measure the blood gas after the surgery at 0 h (T0), 6 h (T6) and 12 h (T12). All male SD rats were subcutaneously injected with normal saline 0.05 ml/g. Subsequently, the male SD rats were sacrificed at 12 h after operation by the blooding and collected samples of lung tissue. The lung tissue wet/dry weight ratio (W/D), myeloperoxidase (MPO) activity, malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) levels, expression of nuclear factor-κB(NF-κB) P65 and IκB-α in the cytoplasm of lung tissue, expression of NF-κB P65 in the nucleus of lung tissue were measured. Pathological changes of lung tissue was observed under light microscope. Another 30 male SD rats were grouped randomly and received the same experiment methods. The survival rate at 24 h was observed. Results Compared with group Ⅰ, the arterial partial pressure of oxygen (PaO2) and activity of SOD were significantly decreased (P<0.05), but the arterial partial pressure of carbon dioxide (PaCO2), lung tissue W/D, activity of MPO, concentration of MDA and NO in the group Ⅱ and group Ⅲ at T6 and T12 were significantly increased (P<0.05). Inflammatory reaction was significantly increased under light microscope in the group Ⅱ. The expression of cytoplasmic NF-κB P65 and IκB-α was decreased (P<0.05), but the expression of nucleus NF-κB P65 was increased in the group Ⅱ(P<0.05). The survival rate of the group Ⅱ in 24 h was lower than the rate in group Ⅰ (P<0.05). Compared with group Ⅱ, the arterial PaO2 and activity of SOD was increased (P<0.05), but the arterial PaCO2, lung tissue W/D, activity of MPO, concentration of MDA and NO were decreased in the group Ⅲ at T6 and T12(P<0.05). Inflammatory reaction was significantly decreased under light microscope in group Ⅲ. The expression of cytoplasmic NF-κB P65 and IκB-α were increased (P<0.05), but the expression of nucleus NF-κB P65 were decreased in group Ⅲ (P<0.05). The survival rate of the group Ⅲ in 24 h was improved (P<0.05). Conclusions DATS has a protective effect on acute lung injury in SD rats. Key words: Diallyl trisulfide; Cecum; Perforation of intestine; Acute lung injury

Analysis of risk factors for perioperative mortality in elderly patients with intertrochanteric fracture.

To investigate risk factors for perioperative death in elderly patients with intertrochanteric fracture. Clinical data from 1051 cases with intertrochanteric fracture from March 2005 to March 2015 were reviewed and analyzed, and causes of death during the perioperative period were statistically analyzed. Various indicators were compared byttest and χ2 test. Multivariateanalysiswas performed usingnon-conditionallogistic regression analysis. Chronic diseases of major organs (heart, brain, and lung), postoperative complications, and various indicators within 24h after admission (albumin, hemoglobin, brain natriuretic peptide [BNP], glucose, creatinine, arterial blood pH, PaO2, and APACHE II) were statistically significantly different between patients who survived and those who died. Logistic regression analysis indicated that postoperative complications, APACHE II score, BNP, and chronic diseases of major organs were the risk factors for perioperative mortality in elderly patients with intertrochanteric fracture. BNP and APACHE II score could be used as important reference indexes for predicting possible perioperative mortality in elderly patients with intertrochanteric fracture and chronic diseases of major organs. Complications after fracture may be also risk factors.

High-Frequency Percussive Ventilation Rescue Therapy in Morbidly Obese Patients Failing Conventional Mechanical Ventilation.

Morbidly obese patients with respiratory failure who do not improve on conventional mechanical ventilation (CMV) often undergo rescue therapy with extracorporeal membrane oxygenation (ECMO). We describe our experience with high-frequency percussive ventilation (HFPV) as a rescue modality. In a retrospective analysis from 2009 to 2016, 12 morbidly obese patients underwent HFPV after failing to wean from CMV. Data were collected regarding demographics, cause of respiratory failure, ventilation settings, and hospital course outcomes. Our end point data were pre- and post-HFPV partial pressure of arterial oxygen and PaO2 to fraction of inspired oxygen (PF) ratios measured at initiation, 2, and 24 hours. Twelve morbidly obese patients required HFPV for respiratory failure. Causes of respiratory failure overlapped and included cardiogenic pulmonary edema (n = 8), pneumonia (n = 5), septic shock (n = 5), and asthma (n = 1). After HFPV initiation, mean fraction of inspired oxygen FiO2 was tapered from 98% to 82% and 66% at 2 and 24 hours, respectively. Mean PaO2 increased from 60.9 mm Hg before HFPV to 175.1 mm Hg (P < .05) at initiation of HFPV, then sustained at 129.5 mm Hg (P < .05) and 88.1 mm Hg (P < .005) at 2 and 24 hours, respectively. Mean PF ratio improved from 66.1 before HFPV to 180.3 (P < .05), 181.0 (P < .05) and 148.9 (P < .0005) at initiation, 2, and 24 hours, respectively. The improvement in mean PaO2 and PF ratios was durable at 24 hours whether or not the patient was returned to CMV (n = 10) or remained on HFPV (n = 2). Survival to discharge was 66.7%. In our cohort of morbidly obese patients, HFPV was successfully utilized as a rescue therapy precluding the need for ECMO. Despite our small sample size, HFPV should be considered as a rescue therapy in morbidly obese patients failing CMV prior to the initiation of ECMO. Our retrospective analysis supports consideration for HFPV as another form of rescue therapy for obese patients with refractory hypoxemia and respiratory failure who are not improving with CMV.