Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Haemodynamic changes during prone positioning in anaesthetised chronic cervical myelopathy patients

Background and Aims: Anaesthetised patients, when positioned prone, experience hypotension and reduction in cardiac output. Associated autonomic dysfunction in cervical myelopathy patients predisposes them to haemodynamic changes. The combined effect of prone positioning and autonomic dysfunction in anaesthetised patients remains unknown. Methods: Thirty adult chronic cervical myelopathy patients, aged 18-65 years with Nurick grade ≥2 were recruited in this prospective observational study. Heart rate, mean blood pressure, cardiac output, stroke volume, total peripheral resistance and stroke volume variation were measured using NICOM®monitor. Data were collected in supine before anaesthetic induction (baseline), 2 minutes after induction, 2 minutes after intubation, before and after prone positioning and every 5 minutes thereafter until skin incision. Repeated measures analysis of variance (ANOVA) was used to analyse the haemodynamic parameters across the time points. Bivariate Spearman's correlation was used to find factors associated with blood pressure changes. A P value <0.05 was kept significant. Results: Cardiac output during the entire study period remained stable (P = 0.186). Sixty percent of the patients experienced hypotension. At 15 and 20 minutes after prone positioning, mean blood pressure decreased (P = 0.001), stroke volume increased (P = 0.001), and heart rate and total peripheral resistance decreased (P < 0.001, P= 0.001, respectively). These changes were significant when compared to pre-prone position values. Number of levels of spinal cord compression positively correlated with the incidence of hypotension. Conclusion: Cervical myelopathy patients experienced hypotension with preserved cardiac output in prone position due to a reduction in total peripheral resistance. Hypotension correlated with the number of levels of spinal cord compression

Airway management in the presence of cervical spine instability: A cross-sectional survey of the members of the Indian Society of Neuroanaesthesiology and Critical Care

Background and Aims: There is a paucity of clinical practice guidelines for the ideal approach to airway management in patients with cervical spine instability (CSI). The aim of this survey was to evaluate preferences, perceptions and practices regarding airway management in patients with CSI among neuroanaesthesiologists practicing in India. Methods: A 25-item questionnaire was circulated for cross-sectional survey to 378 members of the Indian Society of Neuroanaesthesiology and Critical Care (ISNACC) by E-mail. We sent four reminders and again submitted our survey to non-responders during the 2017 annual ISNACC meeting. Apart from demographic information, the survey captured preferred methods of intubation and airway management for patients with CSI and their justification. Regression analysis was used to identify factors associated with the use of indirect technique for intubation. Results: Only 122 out of the 378 anaesthesiologists responded to our survey. Most respondents were senior consultants, working in training hospitals, and performed ≥25 intubations per year for CSI patients. The majority of neuroanaesthesiologists (78.7%; n = 96) preferred indirect techniques for elective intubation. However, 45 anaesthesiologists (36.9%) preferred indirect techniques for emergency intubation. In an adjusted analysis, preference for patients to be conscious during intubation was significantly associated with the use of indirect techniques (odds ratio = 3.79; confidence interval = 1.52–9.49, P < 0.01). Conclusions: Among ISNACC members, indirect techniques are preferred for elective intubation of patients with CSI, while direct laryngoscopy is preferred for emergency intubation

Radiation Safety for Anesthesiologists and Other Personnel on Simultaneous PET/MRI: Possible Radiation Exposure from Patients While Performing Prolonged Duration Scans

This observational study was conducted owing to the challenges of the positron emission tomography/magnetic resonance imaging (PET/MRI) that requires longer duration scanning of radiopharmaceutical injected patient and added MRI environment. The aim of this study was to assess radiation dose at different distances from the patient and the radiation burden to anesthesiologist and other personnel in performing PET/MRI under general anesthesia or sedation. First, the pre- and postscan whole body radiation exposure (WBE) from the patient were obtained for 45 minutes (n = 109) after injection of the radiopharmaceutical. The WBE was obtained at specific distances from brain (10, 30, and 100 cm) and abdomen (10 and 30cm) of patients undergoing F18 fluorodeoxyglucose PET/MRI brain or whole body studies. Second, WBE of the anesthesiologist and other staff working was separately measured using pocket dosimeters during the whole procedure. In brain scans, the mean absorbed dose rates (ADR) of prescan (45 minutes) and postscan (45 minutes) were 44.4 and 31.1 μSv at 10 cm, 14.9 and 9.7μSv at 30 cm, and 3.5 and 2.8 μSv at 100 cm, respectively, from surface of head. Similarly, it was 54.8 and 30.3 μSv at 10 cm, 23 and 13.6μSv at 30 cm, respectively, from surface of abdomen. In WB scans, the mean ADR was higher than the brain scans. Anesthesiologist exposure overall was found to be 4.84 µSv/patient/scan (112 patients). The anesthesiologist receives a safe mean effective dose in PET/MRI scanning. With good training and adequate planning, it is possible to decrease the radiation exposure to all the concerned personnel including anesthesiologists

Lower Bispectral index values in psychiatric patients: A prospective, observational study

Background: Bispectral index score (BIS) is a processed electroencephalographic parameter used to measure level of sedation in anaesthetised patients. In few studies of psychiatric patients undergoing electroconvulsive therapy (ECT), it was observed that the BIS values were lower at baseline. It is not clear from those studies whether the BIS values are really low. Also, it is not clear whether the lower values are related to the primary psychiatric illness or the due to the effect of ECT. Therefore, we studied the BIS values in psychiatric illnesses and compared them with the normal controls. Materials and Methods: BIS index was recorded in 237 patients with various psychiatric illness (Group P) and 40 control patients without any psychiatric illness undergoing spinal surgery (Group C). BIS values were recorded in supine position before breakfast and before the morning doses of antipsychotic/benzodiazepine medications. It was recorded during resting state in all the subjects. Results: BIS values were lower in group P compared to control group (a mean of 89.8 ± 7.8 vs 95.7 ± 2.4, P < 0.0001). In the group P, the patients with psychosis and bipolar disorder had significantly lower BIS values than the patients with depression ( P= 0.04). Conclusions: BIS values in psychiatric patients are lower than those in the control group. Psychotic and bipolar disorders are associated with significantly lower BIS values than the depression

Immunocompromised patients with acute respiratory distress syndrome: Secondary analysis of the LUNG SAFE database

Background: The aim of this study was to describe data on epidemiology, ventilatory management, and outcome of acute respiratory distress syndrome (ARDS) in immunocompromised patients. Methods: We performed a post hoc analysis on the cohort of immunocompromised patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) study. The LUNG SAFE study was an international, prospective study including hypoxemic patients in 459 ICUs from 50 countries across 5 continents. Results: Of 2813 patients with ARDS, 584 (20.8%) were immunocompromised, 38.9% of whom had an unspecified cause. Pneumonia, nonpulmonary sepsis, and noncardiogenic shock were their most common risk factors for ARDS. Hospital mortality was higher in immunocompromised than in immunocompetent patients (52.4% vs 36.2%; p &lt; 0.0001), despite similar severity of ARDS. Decisions regarding limiting life-sustaining measures were significantly more frequent in immunocompromised patients (27.1% vs 18.6%; p &lt; 0.0001). Use of noninvasive ventilation (NIV) as first-line treatment was higher in immunocompromised patients (20.9% vs 15.9%; p = 0.0048), and immunodeficiency remained independently associated with the use of NIV after adjustment for confounders. Forty-eight percent of the patients treated with NIV were intubated, and their mortality was not different from that of the patients invasively ventilated ab initio. Conclusions: Immunosuppression is frequent in patients with ARDS, and infections are the main risk factors for ARDS in these immunocompromised patients. Their management differs from that of immunocompetent patients, particularly the greater use of NIV as first-line ventilation strategy. Compared with immunocompetent subjects, they have higher mortality regardless of ARDS severity as well as a higher frequency of limitation of life-sustaining measures. Nonetheless, nearly half of these patients survive to hospital discharge. Trial registration: ClinicalTrials.gov, NCT02010073. Registered on 12 December 2013

Immunocompromised patients with acute respiratory distress syndrome : Secondary analysis of the LUNG SAFE database

The aim of this study was to describe data on epidemiology, ventilatory management, and outcome of acute respiratory distress syndrome (ARDS) in immunocompromised patients. Methods: We performed a post hoc analysis on the cohort of immunocompromised patients enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) study. The LUNG SAFE study was an international, prospective study including hypoxemic patients in 459 ICUs from 50 countries across 5 continents. Results: Of 2813 patients with ARDS, 584 (20.8%) were immunocompromised, 38.9% of whom had an unspecified cause. Pneumonia, nonpulmonary sepsis, and noncardiogenic shock were their most common risk factors for ARDS. Hospital mortality was higher in immunocompromised than in immunocompetent patients (52.4% vs 36.2%; p < 0.0001), despite similar severity of ARDS. Decisions regarding limiting life-sustaining measures were significantly more frequent in immunocompromised patients (27.1% vs 18.6%; p < 0.0001). Use of noninvasive ventilation (NIV) as first-line treatment was higher in immunocompromised patients (20.9% vs 15.9%; p = 0.0048), and immunodeficiency remained independently associated with the use of NIV after adjustment for confounders. Forty-eight percent of the patients treated with NIV were intubated, and their mortality was not different from that of the patients invasively ventilated ab initio. Conclusions: Immunosuppression is frequent in patients with ARDS, and infections are the main risk factors for ARDS in these immunocompromised patients. Their management differs from that of immunocompetent patients, particularly the greater use of NIV as first-line ventilation strategy. Compared with immunocompetent subjects, they have higher mortality regardless of ARDS severity as well as a higher frequency of limitation of life-sustaining measures. Nonetheless, nearly half of these patients survive to hospital discharge. Trial registration: ClinicalTrials.gov, NCT02010073. Registered on 12 December 2013