Arterial Blood Gas Measurements Research Articles

Outcome of ventilation in patients with hypercapnic respiratory failure in IPF patients: A prospective study

Background: Diffuse parenchymal lung disease (DPLD) is the inflammation and fibrosis of lung interstitium, resulting in respiratory failure. The rate of hypoxic respiratory failure is high as the disease progresses. In idiopathic pulmonary fibrosis (IPF) patients, acute deterioration leads to type 2 respiratory failure, etiology and management of which remains to be completely understood. Aims and Objectives: To identify the causes of type 2 respiratory failure and assess the outcome of invasive and non-invasive ventilation in patients with IPF. Materials and Methods: This prospective single center study included >18-year-old 44 patients with IPF. History of patients, complete blood count, chest radiograph, urine routine, spirometry with bronchodilator reversibility, DLCO (diffusing capacity for carbon monoxide) testing, arterial blood gas measurements, and antinuclear antibody (ANA) test were evaluated. Results: Fourteen (31.8%) patients developed type 2 respiratory failure (within 1.5–6 years from the time of onset of illness). Causes of respiratory failure included acute exacerbation of IPF (35.71%), infections (14.29%), heart failure (14.29%), ischemic heart disease (14.29%), pulmonary embolism (21.43%), pneumothorax (7.14%), and surgical lung biopsy (7.14%). Patients were initiated on non-invasive mechanical ventilation (NIV) (64.29%) and invasive mechanical ventilation (IMV) (35.71%). Eight (88.89%) out of 9 patients on NIV survived, whereas all 5 patients (100%) on IMV expired. Conclusion: Considering the higher mortality rate associated with IMV, NIV is a better technique than IMV for improving patient outcome and management. NIV may be effectively implemented for improving the treatment outcome in patients with IPF and avoiding any aggressive therapeutic approaches.

Progranulin and Activin A Concentrations are Elevated in Serum from Patients with Acute Exacerbations of Idiopathic Pulmonary Fibrosis

PurposeIdiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease of unknown cause with a variable course. Acute exacerbations of IPF (AE-IPF) is sudden accelerations of the disease or a superimposed idiopathic acute injury significantly reducing lung function. To examine the serum concentrations of Progranulin (PGRN) and activin A in patients with AE-IPF in a pilot study.MethodsTwenty-one patients with AE-IPF were compared with 23 patients with stable IPF as a control group. Serum PGRN and activin A levels, arterial blood gas measurements, and lung function were determined in these two groups.ResultsPeripheral blood PGRN and activin A levels in patients with AE-IPF were 83.7 + 10.0 and 14.2 ± 1.7 ng/ml (mean + SD), respectively; higher than those in the control group 61.0 + 5.8 and 5.8 + 1.0 (p < 0.001). PGRN and activin A levels were significantly negatively correlated with carbon monoxide diffusion capacity r = − 0.857 (p < 0.001) and r = − 0.757 (p < 0.001).ConclusionProgranulin (PGRN) and activin A may be involved in the pathogenesis of AE-IPF. They may be possible markers of disease activity in AE-IPF.

Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study.

In patients treated with noninvasive ventilation, sleep-related breathing changes can modify patient-ventilator interactions, which could reduce its effectiveness. The aim of this prospective observational study was to determine the impact of sleep/wake state on leaks, upper airway obstructive events, and asynchronies in patients treated by long-term noninvasive ventilation. Stable patients adapted to noninvasive ventilation were considered for nocturnal polysomnography. Unintentional leaks, upper airway obstructive events, and asynchronies were compared between sleep and awake periods. Twenty-eight patients were enrolled. Underlying diagnoses were neuromuscular disease (n = 11), chest wall disease (n = 8), and obesity-hypoventilation (n = 9). Leaks were more frequent in sleep than in awake periods, with a median of 10% (interquartile range [IQR], 0%-75%) vs 1% (IQR, 0%-9%) of time (P < .001), respectively. During sleep, asynchronies with and without associated leak affected 27% of breaths (IQR, 16%-39%) compared with non-leak-related asynchronies that were recorded in 8% (IQR, 3%-25%) of breaths (P < .001). Asynchronies affecting more than 10% of total breaths were more frequent in sleep (25 patients, 89%) than in awake time (8 patients, 29%; P = .25). Eleven patients (39%) presented with 5 or more upper airway obstructive events without reduction in ventilatory drive per hour of sleep. In patients adapted to home noninvasive ventilation, leaks, asynchronies, and upper airway obstructive events are frequent during the night and are concentrated in sleep periods. Asynchronies are often associated with leaks. These findings may have clinical implications considering that in patients with low sleep efficiency respiratory events could be underestimated if sleep is not evaluated. Martí S, Ferré A, Sampol G, etal. Sleep increases leaks and asynchronies during home noninvasive ventilation: a polysomnographic study. J Clin Sleep Med. 2022;18(1):225-233.

Causes, Effects and Methods of Monitoring Gas Exchange Disturbances during Equine General Anaesthesia.

Simple SummaryHorses are considered to be one of the most challenging domestic species to anaesthetize. Because of the compression of the abdominal visceral organs on the lungs when positioned in dorsal or lateral recumbency, general anaesthesia can cause significant changes to pulmonary function, blood circulation and gas exchange. Consequently, post-operative complications and anaesthetic mortality rates are higher for horses than for other commonly anaesthetized companion animals. There is no ideal method for monitoring respiratory gas concentrations during general anaesthesia, so it is important to know the advantages and limitations of individual methods and the factors that affect monitoring devices. The aim of this review is to summarize previously published studies regarding the causes and effects of intraoperative gas exchange disturbances as well as monitoring methods.Horses, due to their unique anatomy and physiology, are particularly prone to intraoperative cardiopulmonary disorders. In dorsally recumbent horses, chest wall movement is restricted and the lungs are compressed by the abdominal organs, leading to the collapse of the alveoli. This results in hypoventilation, leading to hypercapnia and respiratory acidosis as well as impaired tissue oxygen supply (hypoxia). The most common mechanisms disturbing gas exchange are hypoventilation, atelectasis, ventilation–perfusion (V/Q) mismatch and shunt. Gas exchange disturbances are considered to be an important factor contributing to the high anaesthetic mortality rate and numerous post-anaesthetic side effects. Current monitoring methods, such as a pulse oximetry, capnography, arterial blood gas measurements and spirometry, may not be sufficient by themselves, and only in combination with each other can they provide extensive information about the condition of the patient. A new, promising, complementary method is near-infrared spectroscopy (NIRS). The purpose of this article is to review the negative effect of general anaesthesia on the gas exchange in horses and describe the post-operative complications resulting from it. Understanding the changes that occur during general anaesthesia and the factors that affect them, as well as improving gas monitoring techniques, can improve the post-aesthetic survival rate and minimize post-operative complications.

Serum MCP-1 and NGAL Play an Important Role in the Acute Inflammatory Event of Chronic Obstructive Pulmonary Disease

NGAL is mainly secreted by neutrophils which play the core role in AECOPD. MCP-1 is secreted specifically by monocytes and macrophages. Both biomarkers are involved in the core process of acute inflammatory reaction in COPD. So We analyzed serum NGAL and MCP-1levels to explore their potential clinical values in the chronic obstructive pulmonary disease (COPD) .This study enrolled 97 COPD patients and 50 healthy controls. All participants received blood collection and lung function test and arterial blood gas measurements. The expression levels of serum NGAL and MCP-1 were measured by ELISA. The serum NGAL and MCP-1 levels of COPD with community-acquired pneumonia (COPD-CAP) patients were significantly higher than those of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients and healthy adults. The NGAL levels of the GOLD III and IV groups were significantly higher than those of the GOLD II group. Spearman correlation analysis showed a negative correlation between NGAL and FEV1%pred, FVC% pred. ROC curves indicated that NGAL has a high diagnostic value for both AECOPD and COPD-CAP. NGAL has the value of distinguishing GOLD I and II from GOLD III and IV. MCP-1 have moderate diagnostic value for COPD-CAP and can differentiate COPD-CAP from AECOPD. This study shows NGAL has certain diagnostic value for AECOPD and COPD-CAP, but can not distinguish the two. NGAL is closely related to airway remodeling and can be used as a potential indicator to distinguish the higher GOLD degree. MCP-1 can be used as potential indicator for the diagnosis of COPD-CAP.

Antimicrobial Coating Prevents Ventilator-Associated Pneumonia in a 72 hour Large Animal Model

BackgroundThe primary goal of this study was to demonstrate that endotracheal tubes coated with antimicrobial lipids plus mucolytic or antimicrobial lipids with antibiotics plus mucolytic would significantly reduce pneumonia in the lungs of pigs after 72 hours of continuous mechanical ventilation compared to uncoated controls. Materials and MethodsEighteen female pigs were mechanically ventilated for up to 72 hours through uncoated endotracheal tubes, endotracheal tubes coated with the antimicrobial lipid, octadecylamine, and the mucolytic, N-acetylcysteine, or tubes coated with octadecylamine, N-acetylcysteine, doxycycline, and levofloxacin (6 pigs per group). No exogenous bacteria were inoculated into the pigs, pneumonia resulted from the pigs’ endogenous oral flora. Vital signs were recorded every 15 minutes and arterial blood gas measurements were obtained for the duration of the experiment. Pigs were sacrificed either after completion of 72 hours of mechanical ventilation or just prior to hypoxic arrest. Lungs, trachea, and endotracheal tubes were harvested for analysis to include bacterial counts of lung, trachea, and endotracheal tubes, lung wet and dry weights, and lung tissue for histology. ResultsPigs ventilated with coated endotracheal tubes were less hypoxic, had less bacterial colonization of the lungs, and survived significantly longer than pigs ventilated with uncoated tubes. Octadecylamine-N-acetylcysteine-doxycycline-levofloxacin coated endotracheal tubes had less bacterial colonization than uncoated or octadecylamine-N-acetylcysteine coated tubes. ConclusionEndotracheal tubes coated with antimicrobial lipids plus mucolytic and antimicrobial lipids with antibiotics plus mucolytic reduced bacterial colonization of pig lungs after prolonged mechanical ventilation and may be an effective strategy to reduce ventilator-associated pneumonia.

THE EFFECT OF STRUCTURED TEACHING PROGRAM ON KNOWLEDGE ABOUT ARTERIAL BLOOD GAS ANALYSIS AMONG THE STAFF NURSES WORKING IN CRITICAL CARE UNIT

Statement:A STUDY TO ASSESS THE EFFECT OF STRUCTURED TEACHING PROGRAM ON KNOWLEDGE ABOUT ARTERIAL BLOOD GAS ANALYSIS AMONG THE STAFF NURSES WORKING IN CRITICAL CARE UNIT OF SELECTED HOSPITAL, LUCKNOW Introduction: Arterial blood gas analysis is a basic and useful laboratory test for the critically ill patients. It is an essential investigation for assessing ventilation, oxygenation and acid base status among critically ill patients. These three are closely interrelated physiological parameters which maintain pH homeostasis. Measurement of arterial blood gas involves analysis of components: pH, partial pressure (PP), Base excess (BE), Bicarbonate (HCO3), Electrolytes, Haemoglobin (Hb) and Glucose.Interpreting an arterial blood gas (ABG) is a crucial skill for physicians, nurses, respiratory therapists, and other health care personnel. Any deviation from a normal value will indicate that the client is experiencing an acid base imbalance. Disorders of acid-base balance can lead to severe complications and occasionally the abnormality may be so severe that it can lead to life threatening condition. Objectives Of The Study: 1. Assess the level of knowledge about Arterial Blood Gas analysis among the staff nurses working in the Critical Care Unit at selected Hospital. 2. Evaluate the effect of Structure Teaching Programme on level of knowledge about Arterial Blood Gas Analysis among the staff nurses working in the Critical Care Unit at selected Hospital. 3. Association between level of knowledge about Arterial Blood Gas analysis among the staff nurses working in the Critical Care Unit with selected demographic variables. Research Methodology:This study was conducted using Quantitative approach at Integral Hospital, Lucknow. Pre-experimental one group pre-test-post-test design was used in the study. The conceptual framework used in this study was Modified Kings Goal Attainment theory. The total sample size was 30 selected by convenience sampling technique. The data was collected by administering Structured Knowledge Questionnaire followed by Structured Teaching Programme about Arterial Blood Gas analysis. After 7 days, post-test was done to assess the effectiveness of STP. Reults:The data obtained are tabulated and analysed using descriptive and inferential statistics. The statistical analysis of the data shows that 86.7% of the staff nurses had moderate knowledge and 13.3% of the staff nurses had inadequate knowledge. The mean pretest knowledge score regarding Arterial Blood Gas analysis was 13.96 with a standard deviation of 3.39. After giving STP the mean score was increased to 23.00 with a standard deviation of 2.36. The Structured Teaching Programme was effective in improving the knowledge as the t value is -12.54 which was highly significant with the degree of freedom 29 p&lt; 0.05. Conclusion: The findings revealed that there was a significant improvement in knowledge of staff nurses in post-test after structured teaching programme. It also showed that there was an association with pre-test knowledge and selected demographic variables like age and association of post-test knowledge and selected demographic variable like qualification.

Case Studies in Physiology: Untangling the cause of hypoxemia in a patient with obesity with acute leukemia.

Diagnosing the cause of hypoxemia and dyspnea can be complicated in complex patients with multiple comorbidities. This "Case Study in Physiology" describes an man with obesity admitted to the hospital for relapse of acute lymphoblastic leukemia, who experienced progressive hypoxemia, shortness of breath, and dyspnea on exertion during his hospitalization. After initial empirical treatment with diuresis and antibiotics failed to improve his symptoms and because an arterial blood gas measurement was not readily available, we applied a novel, recently described physiological method to estimate the arterial partial pressure of oxygen from the peripheral saturation measurement and calculate the alveolar-arterial oxygen difference to discern the source of his hypoxemia and dyspnea. Using basic physiological principles, we describe how hypoventilation, anemia, and the use of a β blocker and furosemide, collaborated to create a "perfect storm" in this patient that impaired oxygen delivery and limited utilization. This case illustrates the application of innovative physiology methodology in medicine and provides a strong rationale for continuing to integrate physiology education in medical education.NEW & NOTEWORTHY Discerning the cause of dyspnea and hypoxemia in complex patients can be difficult. We describe the "real world" application of an innovative methodology to untangle the underlying physiology in a patient with multiple comorbidities. This case further demonstrates the importance of applying physiology to interrogate the underlying cause of a patient's symptoms when treatment based on probability fails.

Arterial blood gas measurements during deep open-water breath-hold dives.

Arterial blood gas (ABG) measurements at both maximum depth and at resurfacing prior to breathing have not previously been measured during free dives conducted to extreme depth in cold open-water conditions. An elite free diver was instrumented with a left radial arterial cannula connected to two sampling syringes through a low-volume splitting device. He performed two open-water dives to a depth of 60 m (197', 7 atmospheres absolute pressure) in the constant weight with fins competition format. ABG samples were drawn at 60 m (by a mixed-gas scuba diver) and again on resurfacing before breathing. An immersed surface static apnea, of identical length to the dives and with ABG sampling at identical times, was also performed. Both dives lasted approximately 2 min. Arterial partial pressure of oxygen ([Formula: see text]) increased during descent from an indicative baseline of 15.8 kPa (after hyperventilation and glossopharyngeal insufflation) to 42.8 and 33.3 kPa (dives 1 and 2) and decreased precipitously (to 8.2 and 8.6 kPa) during ascent. Arterial partial pressure of carbon dioxide ([Formula: see text]) also increased from a low indicative baseline of 2.8 kPa to 6.3 and 5.1 kPa on dives 1 and 2; an increase not explained by metabolic production of CO2 alone since [Formula: see text] actually decreased during ascent (to 5.2 and 4.5 kPa). Surface static apnea caused a steady decrease in [Formula: see text] and increase in [Formula: see text] without the inflections provoked by depth changes. Lung compression and expansion provoke significant changes in both [Formula: see text] and [Formula: see text] during rapid descent and ascent on a deep free dive. These changes generally support predictive hypotheses and previous findings in less extreme settings.NEW & NOTEWORTHY Arterial blood gas measurements at both maximum depth and the surface before breathing on the same dive have not previously been obtained during deep breath-hold dives in cold open-water conditions and competition dive format. Such measurements were obtained in two dives to 60 m (197') of 2 min duration. Changes in arterial oxygen and carbon dioxide (an increase during descent, and a decrease during ascent) support previous observations in less extreme dives and environments.

Impaired hypoxic ventilatory drive induced by diabetic autonomic neuropathy, a cause of misdiagnosed severe cardiac events: brief report of two cases

BackgroundSudden cardiac deaths are twice more frequent in diabetic patients with cardiac autonomic neuropathy. Sudden cardiac death etiologies remain unclear and no recommendations are made to identify factors associated with cardiorespiratory arrest in diabetic patients. We hypothesized, from two clinical cases, that impaired hypoxic ventilatory drive, induced by diabetic autonomic neuropathy, is a cause of misdiagnosed severe cardiac events.Case presentationWe describe the cases of two patients with isolated low blood saturation on pulse oximeter during the systematic nurse check-up (77% and 85% respectively) contrasting with the absence of any complaint such as dyspnea, polypnea or other respiratory insufficiency signs observed during the clinical examination. Arterial blood gas measurements subsequently confirmed that blood oxygen saturation was low and both patients were indeed hypoxemic. Patient 1 suffered from vascular overload complicated by cardiac arrest caused by hypoxemia in light of the quick recovery observed after ventilation. Pulmonary edema was diagnosed in patient 2. The common denominator of these 2 cases described in this brief report is the absence of respiratory failure clinical signs contrasting with the presence of confirmed hypoxemia. Also, in both cases, such absence of precursory signs seems to be induced by an impaired ventilatory drive to hypoxemia. This appears to be related to the autonomic diabetic neuropathy encountered in those 2 patients.ConclusionsTherefore, we describe, in this brief report, cardiac autonomic neuropathy as a cause of impaired hypoxic ventilatory drive involved in severe acute cardiorespiratory events in two type 1 diabetic patients. We assume that altered response to hypoxemia due to cardiac autonomic neuropathy and non-functional central neurological breathing command could play a key role in sudden deaths among diabetic patients. An important point is that hypoxemia can be easily missed since no clinical signs of respiratory failure are reported in these two clinical cases. Systematic screening of cardiac autonomic neuropathy in diabetic patients and proactive detection of impaired hypoxic ventilatory drive for early management (e.g. treatment of hypoxemia) should be systematically undertaken in diabetic patients to prevent its dramatic consequences such as cardiorespiratory arrest and death.

Assessment of the SpO2/FiO2 ratio as a tool for hypoxemia screening in the emergency department.

ObjectiveWe assessed the performance of the ratio of peripheral arterial oxygen saturation to the inspired fraction of oxygen (SpO2/FiO2) to predict the ratio of partial pressure arterial oxygen to the fraction of inspired oxygen (PaO2/FiO2) among patients admitted to our emergency department (ED) during the SARS-CoV-2 outbreak.MethodsWe retrospectively studied patients admitted to an academic-level ED in France who were undergoing a joint measurement of SpO2 and arterial blood gas. We compared SpO2 with SaO2 and evaluated performance of the SpO2/FiO2 ratio for the prediction of 300 and 400 mmHg PaO2/FiO2 cut-off values in COVID-19 positive and negative subgroups using receiver-operating characteristic (ROC) curves.ResultsDuring the study period from February to April 2020, a total of 430 arterial samples were analyzed and collected from 395 patients. The area under the ROC curves of the SpO2/FiO2 ratio was 0.918 (CI 95% 0.885–0.950) and 0.901 (CI 95% 0.872–0.930) for PaO2/FiO2 thresholds of 300 and 400 mmHg, respectively. The positive predictive value (PPV) of an SpO2/FiO2 threshold of 350 for PaO2/FiO2 inferior to 300 mmHg was 0.88 (CI95% 0.84–0.91), whereas the negative predictive value (NPV) of the SpO2/FiO2 threshold of 470 for PaO2/FiO2 inferior to 400 mmHg was 0.89 (CI95% 0.75–0.96). No significant differences were found between the subgroups.ConclusionsThe SpO2/FiO2 ratio may be a reliable tool for hypoxemia screening among patients admitted to the ED, particularly during the SARS-CoV-2 outbreak.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Pediatric Extracorporeal Cardiopulmonary Resuscitation ELSO Guidelines.

Repeated unconsciousness due to chronic carbon monoxide poisoning in an older patient: a case report.

Objective: Although much is known about acute carbon monoxide (CO) poisoning, little is known about chronic CO poisoning. Chronic CO poisoning is often diagnosed based on the patient’s living environment and medical history. Herein, we report the case of an older patient who presented with repeated unconsciousness due to chronic CO poisoning.Case presentation: A 90-year-old man was brought to the emergency department after being found at home with a disturbance of consciousness. Arterial blood gas measurements in room air revealed a carboxyhemoglobin level of 18.0%. Impaired consciousness was caused by chronic CO poisoning. The patient received high-flow oxygen therapy, which promptly improved his condition. According to his family, briquette kotatsu was the cause of chronic CO poisoning.Conclusion: Although high-flow oxygen therapy has been said to be less effective than hyperbaric oxygen therapy in CO poisoning treatment, recent studies have demonstrated that high-flow oxygen has similar effects and benefits. Thus, in institutions that do not have hyperbaric oxygen, high-flow oxygen may be sufficient to treat patients with CO poisoning, as seen in the present case. It should be noted that briquette kotatsu can lead to CO poisoning. This case highlights the need for clinicians to consider patients’ living conditions.

Arterial Blood Gases as an Indicator of Early ICU Admission in Chest Trauma Patients

Background: Trauma is injury to living tissue caused by an extrinsic agent. Trauma is a Greek word which means body injury. Blunt chest trauma causes 25% of traumatic deaths. It is commonly associated with multiple organ damage which leads to catastrophic patient outcome. Blunt chest trauma is more common than penetrating chest trauma. Arterial blood gas (ABG) studies report the degrees of acidemia, hypercarbia, and hypoxemia, which depend on cardiopulmonary status at the time of collection. Objective: To determine the value of ABG measurements in patients with blunt chest trauma and its role in prognosis of different outcomes. Patients and Methods: This study included 100 patients arrived to Emergency Department (ED) in Emergency Hospital-Mansoura University during the period from 1-8-2019 to 1-8-2020. Patients were divided to subtypes according to ward or ICU admissions and presence or absence of lung injury. Length of hospital stay as outcome was also reported. Results: ABG and combined ABG measurements are strongly reflecting the clinical situation of chest trauma patients. It can predict longer length of hospital stay. PCO2 is more sensitive than HCO3- in prediction of ICU admission in chest trauma patients. SaO2, combined ABG analysis had higher sensitivity in prediction of ICU admission in chest trauma patients. HCO3- level and combined ABG were statistically significant in prediction of lung injury among studied patients with high specificity. Conclusion: ABG values and combined ABG values seemed to have a promising role in determination of patients admitted to ward versus others admitted in ICU.

Inhaled Molgramostim Therapy in Autoimmune Pulmonary Alveolar Proteinosis

BackgroundAutoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease characterized by progressive surfactant accumulation and hypoxemia. It is caused by disruption of granulocyte–macrophage colony-stimulating factor (GM-CSF) signaling, which pulmonary alveolar macrophages require to clear surfactant. Recently, inhaled GM-CSF was shown to improve the partial pressure of arterial oxygen in patients with aPAP.MethodsIn a double-blind, placebo-controlled, three-group trial, we randomly assigned patients with aPAP to receive the recombinant GM-CSF molgramostim (300 μg once daily by inhalation), either continuously or intermittently (every other week), or matching placebo. The 24-week intervention period was followed by an open-label treatment-extension period. The primary end point was the change from baseline in the alveolar–arterial difference in oxygen concentration (A-aDo2) at week 24.ResultsIn total, 138 patients underwent randomization; 46 were assigned to receive continuous molgramostim, 45 to receive intermittent molgramostim, and 47 to receive placebo. Invalid A-aDo2 data for 4 patients (1 in each molgramostim group and 2 in the placebo group) who received nasal oxygen therapy during arterial blood gas measurement were replaced by means of imputation. For the primary end point — the change from baseline in the A-aDo2 at week 24 — improvement was greater among patients receiving continuous molgramostim than among those receiving placebo (−12.8 mm Hg vs. −6.6 mm Hg; estimated treatment difference, −6.2 mm Hg; P=0.03 by comparison of least-squares means). Patients receiving continuous molgramostim also had greater improvement than those receiving placebo for secondary end points, including the change from baseline in the St. George’s Respiratory Questionnaire total score at week 24 (−12.4 points vs. −5.1 points; estimated treatment difference, −7.4 points; P=0.01 by comparison of least-squares means). For multiple end points, improvement was greater with continuous molgramostim than with intermittent molgramostim. The percentages of patients with adverse events and serious adverse events were similar in the three groups, except for the percentage of patients with chest pain, which was higher in the continuous-molgramostim group.ConclusionsIn patients with aPAP, daily administration of inhaled molgramostim resulted in greater improvements in pulmonary gas transfer and functional health status than placebo, with similar rates of adverse events. (Funded by Savara Pharmaceuticals; IMPALA ClinicalTrials.gov number, NCT02702180.)

Electrocardiographic findings of methanol toxicity: a cross-sectional study of 356 cases in Iran

BackgroundMethanol is widely used in industry; however, methanol poisoning is not common. In this regard, a number of outbreaks have been recently reported due to inappropriate processing of alcoholic beverages. Shiraz, a city located in the southern part of Iran, faced one of such outbreaks in 2020 during COVID-19 pandemic. There is no sufficient literature on the electrocardiographic findings in methanol toxicity. This study aimed to address this gap in the literature.MethodA total of 356 cases with methanol toxicity referred to Shiraz University of Medical Science Tertiary Hospitals (Faghihi and Namazi) in March and April, 2020. The clinical findings of blindness and impaired level of consciousness, lab data such as arterial blood gas, electrolytes, and creatinine, and the most common findings from ECGs were collected.ResultsThe most common ECG findings were J point elevation (68.8%), presence of U wave (59.2%), QTc prolongation (53.2% in males and 28.6% in females), and fragmented QRS (33.7%). An outstanding finding in this study was the presence of myocardial infarction in 5.3% of the cases. This finding, to the best of our knowledge, has only been reported in a few case reports. Brugada pattern (8.1%) and Osborn wave (3.7%) were the other interesting findings.In multivariate analysis, when confounding factors were adjusted, myocardial infarction, atrioventricular conduction disturbances, sinus tachycardia, and the prolonged QTC > 500 msecond were four independent factors correlated with methanol toxicity severity measured with arterial blood PH on arterial blood gas measurements, with odds ratios of 12.82, 4.46, 2.32 and 3.15 (P < 0.05 for all), respectively.ConclusionElectrocardiographic variations during methanol intoxication are remarkable and well-correlated with poisoning severity. Myocardial infarction was an egregious and yet a common concerning finding in this sample, which need to be ruled out in methanol toxicity.

Hypocapnia, ischemic lesions, and outcomes after intracerebral hemorrhage

BackgroundAn association between spontaneous hyperventilation, delayed cerebral ischemia, and poor clinical outcomes has been reported in subarachnoid hemorrhage. We evaluated the relationship between early pCO2 changes, ischemic lesions and outcomes in patients with intracerebral hemorrhage (ICH). MethodsConsecutive patients with spontaneous ICH were enrolled in an observational cohort study conducted between 2006 and 2019. Patient characteristics and discharge outcome were prospectively recorded. Arterial blood gas (ABG) measurements and mechanical ventilation settings in the first 72 h of admission were retrospectively collected. MRI images were adjudicated for diffusion-restricted lesions consistent with ischemia and distant from the hematoma. We examined the associations between pCO2 changes, ischemic lesions, and discharge outcomes by univariate and adjusted analyses. ResultsABG data were available for 220 patients. Hyperventilation occurred in 52 (28%) cases and was not associated with clinical severity. Lower initial pCO2 was associated with greater risk of in-hospital death (OR 0.94 per mmHg, 95%CI [0.89, 0.996], p = 0.042) after adjustment for ICH Score, pneumonia and mechanical ventilation requirements. MRI data were available for 33 patients. Lower pCO2 was associated with a higher risk of ischemic lesions, except in patients with low initial systolic blood pressure (p < 0.05 for main and blood pressure interaction effects), after adjustment for other predictors. ConclusionsIn ICH patients with spontaneous ventilation, lower pCO2 was independently associated with greater risk of in-hospital death. In patients with elevated initial blood pressure, who undergo blood pressure reduction per guideline recommendations, lower pCO2 was associated with increased risk to develop ischemic lesions.

Gas Exchange and Ventilatory Efficiency During Exercise in Pulmonary Vascular Diseases

Background and ObjectiveVentilatory inefficiency (high V′E/V′CO2) and resting hypocapnia are common in pulmonary vascular disease and are associated with poor prognosis. Low resting PaCO2 suggests increased chemosensitivity or an altered PaCO2 set-point. We aimed to determine the relationships between exercise gas exchange variables reflecting the PaCO2 set-point, exercise capacity, hemodynamics and V′E/V′CO2. MethodsPulmonary arterial hypertension (n=34), chronic thromboembolic pulmonary hypertension (CTEPH, n=19) and pulmonary veno-occlusive disease (PVOD, n=6) patients underwent rest and peak exercise arterial blood gas measurements during cardiopulmonary exercise testing. Patients were grouped according to resting PaCO2: hypocapnic (PaCO2 ≤34mmHg) or normocapnic (PaCO2 35–45mmHg). The PaCO2 set-point was estimated by the maximal value of end-tidal PCO2 (maximal PETCO2) between the anaerobic threshold and respiratory compensation point. ResultsThe hypocapnic group (n=39) had lower resting cardiac index (3.1±0.8 vs. 3.7±0.7L/min/m2, p<0.01), lower peak V′O2 (15.8±3.5 vs. 20.7±4.3mL/kg/min, p<0.01), and higher V′E/V′CO2 slope (60.6±17.6 vs. 38.2±8.0, p<0.01). At peak exercise, hypocapic patients had lower PaO2, higher VD/VT and higher P(a-ET)CO2. Maximal PETCO2 (r=0.59) and VD/VT (r=−0.59) were more related to cardiac index than PaO2 or PaCO2 at rest or peak exercise. Maximal PETCO2 was the strongest correlate of V′E/V′CO2 slope (r=−0.86), peak V′O2 (r=0.64) and peak work rate (r=0.49). ConclusionsResting hypocapnia is associated with worse cardiac function, more ventilatory inefficiency and reduced exercise capacity. This could be explained by elevated chemosensitivity and lower PaCO2 set-point. Maximal PETCO2 may be a useful non-invasive marker of PaCO2 setpoint and disease severity even with submaximal effort.

Serum bicarbonate level improves specificity of Berlin Sleep Questionnaire for obstructive sleep apnea

Several questionnaires have been developed to assist the diagnostic process in obstructive sleep apnea syndrome (OSAS). Berlin Sleep Questionnaire (BSQ) represents a validated screening tool for OSAS. Totally 450 patients admitted to the Sleep Center at Dicle University Medical Faculty were included prospectively. A risk analysis was performed for presence of OSAS using the BSQ. Arterial blood gas measurements were performed including bicarbonate (HCO3) level. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of BSQ for presence of OSAS and severe OSAS were determined. In patients with arterial HCO3 >24.94 mEq/L; sensitivity, specificity, PPV and NPV, of the BSQ were 93.04, 57.1, 98.3, and 23.5%, respectively. The addition of arterial HCO3 value increased the sensitivity of the BSQ in detecting OSAS patients. Although the cost of sleep studies is high for false positives from the BSQ plus arterial HCO3 level, this cost should be compared with the loss of work efficiency and severe healthcare costs of undiagnosed cases in the future. Therefore, finding possible OSAS cases in primary care health centers is important and adding serum HCO3 value to BSQ questionnaire may contribute to this topic.

Effect of dexmedetomidine as a sedative in sub-dural hematoma evacuation surgeries

Background &amp; objective: We studied the safety and effectiveness of combination of dexmedetomidine and fentanyl for chronic sub-dural hematoma (CSDH) evacuation. Main objectives of the study was to register the effects on the combination on the cardio-respiratory and analgesic outcome.&#x0D; Methodology: 56 patients with CSDH were divided into two group. Patients of Group A received dexmedetomidine 1 µg/kg over a period of 10 min with fentanyl 1 µg/kg, followed by an infusion of dexmedetomidine 0.3 µg/kg/min. Group B received fentanyl 1 µg/kg and midazolam 0.03 mg/kg IV. Sedation scores, hemodynamic changes and serial arterial blood gas (ABG) measurements were compared between the two groups.&#x0D; Results: Heart rate and diastolic blood pressure were significantly lower in Group A compared to Group B throughout the observation period after premedication. Systolic blood pressure readings was significantly lower in Group A compared to Group B from 10 min onwards till the end. ABG analysis showed that Group A had significantly lower PCO2 levels during and at the end of surgery and significantly higher PO2 at the end of procedure.&#x0D; Conclusion: The use of dexmedetomidine is associated with significantly higher PO2 at the end of the surgical procedure. It results in lower heart rate, systolic and diastolic blood pressures and PCO2 levels during and at the end of the subdural hematoma evacuation, but the fall remains within the physiological range.