High-flow Group Research Articles

Hypocoagulable Coagulation Profile and Endogenous Heparinoids Are Associated with Invasive Ventilation and Mortality in COVID-19

Background & Aims: A procoagulant state with pulmonary micro-thrombosis has been described in COVID-19, which contributes to pathophysiology of respiratory failure along with diffuse alveolar damage. Cytokine storm and systemic inflammation in COVID-19 generates endogenous heparinoids from the endothelium which leads to secondary organ failures. We prospectively studied the dynamic association of the coagulation abnormalities with respiratory failure and mortality in patients with COVID-19.Methods: We did a prospective observational study in adults aged between 18-80 years with COVID 19 pneumonia requiring intensive care (ICU) admissions in a tertiary care hospital in North India. All patients received standard medical therapy based on best available evidence. Patients were categorized based on the oxygen support therapy into low flow, high flow and invasive ventilation groups. In patients considered to be at risk of thromboembolic or bleeding phenomena, paired coagulation tests were performed at days 1 and 3 with, Sonoclot ® (glass beaded and heparinase-treated). All patients were consecutively followed for inflammatory markers, ventilator requirements and survival. Activated clotting time (ACT) 75 units were used as the cut-off for hypercoagulable state. The heparin like effect (HLE) was considered by a correction of ≥ 40 s in hACT (heparinized treated ACT). The trial is registered with ClinicalTrials.gov (NCT04668404).Results: A total of 2324 patients with COVID-19 were screened from August 2020 to November 2020. Two hundred and fifteen patients requiring ICU admission were assessed and 74 patients with a median age of 54(42-67) years were enrolled. A procoagulant profile was seen in 45.5%, 32.4% and 20.7% in low-flow, high-flow, and invasive ventilation. Paired Sonoclot ® assays in 33 patients demonstrated HLE in 17 (51.5%) and 20 (62.5%) at days 1 and 3 respectively. In multivariate analysis, the presence of HLE (HR 1.02; CI 1.08-1.6; p 131 s, clot rate 96.7 mg/l at admission predicted mortality.Conclusions: HLE contributes to hypocoagulable effect, need for invasive ventilation and mortality in patients with COVID-19.Trial Registration: The trial is registered with ClinicalTrials.gov (NCT04668404).Funding Statement: NoneDeclaration of Interests: NoneEthics Approval Statement: Ethical clearance was obtained from the Institutional Review Board (PGI/IEC/2020/000997 dated 24 August 2020)

A Dual-Scaffolding Framework Integrating Peer-Scaffolding and Cognitive-Scaffolding for an Augmented Reality-Based Educational Board Game: An Analysis of Learners’ Collective Flow State and Collaborative Learning Behavioral Patterns

The design and application of educational board games have been emphasized in game-based learning. The integration of educational board games and augmented reality (AR) can help provide extensive cognitive-scaffolding for learners. This study proposed a dual-scaffolding framework that integrated peer-scaffolding and cognitive-scaffolding for an AR educational board game. This study also conducted an empirical analysis to evaluate this framework. Forty-four college students participated in this study. The researchers investigated these learners’ flow, acceptance, and their collaborative learning behavioral patterns with the sequential analysis. Moreover, this study explored the correlation of flow and acceptance and investigated learners’ behavioral pattern differences between high collective flow groups and low collective flow groups (collective flow referred to the mean of flow from group members). The results showed that there was a positive correlation between learners’ flow and acceptance. These learners’ behavioral patterns also showed that both peer-scaffolding and cognitive-scaffolding facilitated their problem-solving process. Moreover, the study found that high collective flow groups had more reflection and analysis behaviors than low collective flow groups in game-based learning.

First-line oxygen therapy with high-flow in bronchiolitis is not cost saving for the health service

BackgroundBronchiolitis is the most common reason for hospital admission in infants. High-flow oxygen therapy has emerged as a new treatment; however, the cost-effectiveness of using it as first-line therapy is...

Clinical Value of Intraoperative Flow Measurements of Brachiocephalic Arteriovenous Fistulas for Hemodialysis

BackgroundThe aim of this study was to analyze the clinical outcomes of autogenous brachiocephalic arteriovenous fistulas and to investigate the factors associated with 1-year patency after initiation of hemodialysis.MethodsWe retrospectively reviewed the medical records of 41 patients who underwent surgery to create an autogenous brachiocephalic arteriovenous fistula between January 2015 and December 2017, received hemodialysis at the same hospital for longer than 1 year, and were monitored for their vascular access status. Intraoperative flow was measured using transit-time ultrasonography.ResultsThe 1-year primary and secondary patency rates were 61% (n=25) and 87.8% (n=36), respectively. The functional group (subjects who required no intervention to maintain patency within the first year after hemodialysis initiation) displayed a significantly higher median intraoperative flow rate (450 mL/min) than the non-functional group (subjects who required intervention at least once regardless of 1-year patency) (275 mL/min) (p=0.038). Based on a receiver operating characteristic curve analysis, all patients were additionally subdivided into a high-flow group (>240 mL/min) and a low-flow group (≤240 mL/min). The high-flow group included a significantly greater number of functional brachiocephalic arteriovenous fistulas than the low-flow group (74.2% vs. 20%, respectively; p=0.007).ConclusionTransit-time flow, as measured with intraoperative transit-time ultrasonography, was associated with patency without the need for intervention at 1 year after initiation of hemodialysis.

P1322EFFECTS OF HAEMODIALYSIS ARTERIOVENOUS FISTULA CREATION ON CARDIAC STRUCTURE AND FUNCTION

Abstract Background and Aims Arteriovenous fistula (AVF) is considered the preferred type of access for maintenance haemodialysis. The creation of an AVF may contribute to maladaptive cardiovascular remodelling. We conducted a study to evaluate the effect of AVF creation on cardiac structure and function in patients with end-stage renal disease (ESRD). Method In this prospective cohort study, patients with ESRD listed for AVF creation underwent cardiac magnetic resonance imaging at baseline and at 6 weeks. All participants had ultrasound measurements of AVF blood flow at 6 weeks. The primary outcome was the change in left ventricular (LV) mass. Secondary outcomes included changes in LV volumes, left atrial volume, LV ejection fraction, LV global longitudinal strain, cardiac output/index, and septal thickness. Results A total of 65 patients were enrolled, of whom 40 had an AVF creation and completed both scans. Patients were divided into 2 groups based on AVF blood flows: 22 in the high flow group (≥ 600mL/min) and 18 in the low flow group (< 600mL/min). On the second cardiac magnetic resonance scan, a mean increase of 7.4 g (95% CI, 1.1–13.7, P=0.02) was observed in LV mass; in the high flow group the mean increase was 15.5 g (95% CI, 7.3–23.8) compared with a small decrease of 2.5 g (95% CI, −10.6 to 5.6) in the low flow group (P=0.003). Significant increases in LV end-diastolic volumes, cardiac output, and cardiac index were also seen after AVF creation (P<0.04). No significant changes were observed in LV ejection fraction (P=0.52), LV end-systolic volumes (P=0.12), and LV global longitudinal strain (P=0.21). Conclusion Creation of AVF in adults with ESRD resulted in significant increase of LV myocardial mass early after surgery.

High flow oxygen for dyspnea in hospitalized patients with cancer: A 4x4 crossover randomized clinical trial.

12077 Background: Dyspnea is common in hospitalized cancer patients and highly distressing. High flow oxygen (HFOx) is administered for oxygenation in this setting; however, its effect on dyspnea has not been well examined, particularly among non-hypoxemic patients. In this phase II trial, we assessed the effect of HFOx, high flow air (HFAir), low flow oxygen (LFOx) and low flow air (LFAir) on dyspnea. We hypothesized that HFO and HFA can alleviate dyspnea. Methods: This double-blind, 4x4 crossover clinical trial enrolled hospitalized patients with cancer who were dyspneic (NRS ≥3 at rest) and non-hypoxemic (SpO2>90% on room air). Patients were randomized to 10 minutes of HFOx, HFAir, LFOx and LFAir in different orders. The flow rate was titrated between 20-60 L/min in the high flow groups and 2 L/min in the low flow groups. The primary outcome was dyspnea 0-10 numeric rating scale (NRS) “now”, where 0=none and 10=worst. Secondary outcomes included modified Borg scale dyspnea intensity and unpleasantness, adverse effects, and overall preference. We compared among the interventions with a linear mixed model adjusting for time, treatment effect, period effect and carryover effect. Results: 17 patients completed 55 interventions in a random order. Mean age 51, 58% female, mean baseline dyspnea NRS 6.3 (SD 1.7). The absolute change of dyspnea NRS between 0 and 10 minutes was -1.8 (SD 1.7) for HFOx, -1.8 (2.0) for HFAir, -0.5 (0.8) for LFOx and -0.6 (1.2) for LFAir. In mixed model analysis, HFOx group provided greater dyspnea relief than LFOx (mean difference [95% CI] -0.80 [-1.45, -0.15], P=0.02) and LFAir (-1.24 [-1.90, -0.57], P<0.001). HFAir also provided a significantly greater dyspnea relief than LFOx (-0.95 [-1.61, -0.30], P=0.005) and LFAir (-1.39 [-2.05, -0.73], P<0.001). No difference was found between HFOx and HFAir nor between LFOx and LFAir. There was no significant carryover effect. Dyspnea Borg scale intensity and unpleasantness showed similar changes. Oxygen saturation increased in the HFOx group (97.2% to 99.7%) and LFOx group (95.5% to 98.2%) but not HFAir nor LFAir groups. HFOx was well tolerated. At the end of the study, 7 (54%), 4 (31%), 1 (8%) and 1 (8%) patients blindly preferred HFOx, HFAir, LFOx and LFAir, respectively. Conclusions: For the first time, we found that HFOx and HFAir provided a rapid and clinically significant reduction of dyspnea at rest in hospitalized cancer patients even when they were non-hypoxemic, supporting a role for high flow devices to provide palliation beyond oxygenation. Larger studies are needed to confirm these findings. Clinical trial information: NCT02932332 .

Apnoeic oxygenation and ventilation: go with the flow

Apnoeic oxygenation and ventilation: go with the flow

Comparative study of different epidural infusion sets at maximum speeds for labor analgesia

Abstract Introduction The higher injection pressure obtained with epidural boluses give greater anaesthetic spread, and therefore better sensory block. Therefore, it stands to reason that anaesthetic administered at greater injection pressure and a higher flow rate would spread to a higher sensory level. Objective Our aim was to compare the sensory level reached with the high flow and standard flow set at maximum rates. Material and methods We included 73 primiparous women who requested epidural analgesia for labor using programmed intermittent epidural boluses of 0.1% ropivacaine at a flow rate of 10 ml/h and 2 μg/ml fentanyl plus patient-controlled epidural analgesia. The boluses were administered with a standard (250 ml/h) or high-flow (500 ml/h) infusion set, according to the usual clinical practice of each anaesthesiologist. The primary objective was to evaluate the sensory level reached. Secondary objectives were pain on a visual analogue scale, motor block measured on the modified Bromage scale, and anaesthesia consumption in terms of rescue analgesia (patient-controlled epidural analgesia) and anaesthesiologist-administered boluses. Results The median maximum sensory level reached was T9 in the high flow group and T7 in the standard flow group; this difference was statistically significant (p = 0.0002). There were no significant differences in visual analogue scale, Bromage or rescue analgesia between groups. Conclusion Our results show that the high flow set does not offer benefits. The use of such sets need to be evaluated due to their higher cost.

A change from high-flow to titrated oxygen therapy in the prehospital setting is associated with lower mortality in COPD patients with acute exacerbations: an observational cohort study

Background: The aim of this study was to investigate 30-day mortality for COPD patients treated by ambulances in the period before and after implementation of a pre-hospital oxygen protocol. Methods: Prehospital High-flow oxygen was used from April to September 2012 and titrated oxygen from April to September 2013. Primary outcome was 30-day mortality. Results: 707 patients were included; 209 in the high-flow group and 498 in the titration group. Of these, 56 and 132 arrived with acute exacerbation (AE). Overall 30-day mortality was 11.5% vs. 9.4% (p=0.41), respectively. For patients with AE, it was 19.6% vs. 4.6% (p=0.001). Conclusion: Change of treatment protocol is associated with a lower 30-day mortality for patients registered with acute exacerbation, but not for all COPD patients.

Estudio comparativo de diferentes sets de infusión epidural a velocidades máximas para analgesia del parto

IntroductionThe higher injection pressure obtained with epidural boluses give greater anaesthetic spread, and therefore better sensory block.Therefore, it stands to reason that anaesthetic administered at greater injection pressure and a higher flow rate would spread to a higher sensory level. ObjectiveOur aim was to compare the sensory level reached with the high flow. and standard flow set at maximum rates. Material and methodsWe included 73 primiparous women who requested epidural analgesia for labour using programmed intermittent epidural boluses of 0.1% ropivacaine at a flow rate of 10ml/h and 2 ug/ml fentanyl plus patient-controlled epidural analgesia. The boluses were administered with a standard (250ml/h) or high-flow (500ml/h) infusion set, according to the usual clinical practice of each anaesthesiologist. The primary objective was to evaluate the sensory level reached. Secondary objectives were pain on a visual analogue scale, motor block measured on the modified Bromage scale, and anaesthesia consumption in terms of rescue analgesia (patient-controlled epidural analgesia) and anaesthesiologist-administered boluses. ResultsThe median maximum sensory level reached was T9 in the high flow group and T7 in the standard flow group; this difference was statistically significant (p=.0002). There were no significant differences in visual analogue scale, Bromage or rescue analgesia between groups. ConclusionOur results show that the high flow set does not offer benefits. The use of such sets need to be evaluated due to their higher cost.

Desfluranın Aynı Konsantrasyonda Fakat Farklı Akımlarda Kullanılması Oksidatif Stresi Değiştiştirir mi? Hayvan Deneyi

It is known that inhalation anesthetics are effective in the formation of oxidative stress and free radicals. The purpose of this study is to investigate these effects of desflurane and to detect changes in different flows. The rats were divided into three groups (10 mice/group). The first group was the control group. In the second group, mice were sedated with ketamine and given desflurane at a concentration of 6% in a 100% oxygen flow at a flow rate of 8 lt / min in a glass box for 20 minutes. The third group was comprised of ketamine-sedated mice that were given desflurane at a concentration of 6% in a 100% oxygen flow at a flow rate of 2 lt/min in a glass box for 20 minutes. Biochemical parameters were measured using commercial kits. Serum, brain, liver tissue MDA and SOD levels were significantly higher in the high flow group than in the control and low flow group. Serum GPx levels were significantly lower in the high flow group compared to both groups. ADMA levels in the serum, liver, and brain tissue were significantly higher in the high flow group. There was no significant difference in serum 8-OHdG levels between all three groups. Brain and liver tissue 8-OHDG levels were higher in both groups than control group. It has been observed that the use of low flow fresh gas even in the same concentrations of desflurane anesthesia models decreases oxidative stress whereas the use of high flow increases oxidative stress.

High-Flow Nasal Oxygen Improves Safe Apnea Time in Morbidly Obese Patients Undergoing General Anesthesia: A Randomized Controlled Trial.

Morbidly obese patients undergoing general anesthesia are at risk of hypoxemia during anesthesia induction. High-flow nasal oxygenation use during anesthesia induction prolongs safe apnea time in nonobese surgical patients. The primary objective of our study was to compare safe apnea time, between patients given high-flow nasal oxygenation or conventional facemask oxygenation during anesthesia induction, in morbidly obese surgical patients. Research ethics board approval was obtained. Elective surgical patients ≥18 years with body mass index ≥40 kg·m were included. Patients with severe comorbidity, gastric reflux disease, known difficult airway, or nasal obstruction were excluded. After obtaining informed consent patients were randomized. In the intervention (high-flow nasal oxygenation) group, preoxygenation was provided by 100% nasal oxygen for 3 minutes at 40 L·minute; in the control group, preoxygenation was delivered using a facemask with 100% oxygen, targeting end-tidal O2 >85%. Anesthesia was induced with propofol, remifentanil, and rocuronium. Bag-mask ventilation was not performed. At 2 minutes after rocuronium, videolaryngoscopy was performed. If the laryngoscopy grade was I or II, laryngoscope was left in place and the study was continued; if grade III or IV was observed, the patient was excluded from the study. During the apnea period, high-flow nasal oxygenation patients received nasal oxygen at 60 L·minute; control group patients received no supplemental oxygen. The primary outcome, safe apnea time, was reached when oxygen saturation measured by pulse oximetry (SpO2) fell to 95% or maximum 6 minutes of apnea. The patient was then intubated. T tests and χ analyses were used to compare groups. P < .05 was considered significant. Forty patients completed the study. Baseline parameters were comparable between groups. Safe apnea time was significantly longer (261.4 ± 77.7 vs 185.5 ± 52.9 seconds; mean difference [95% CI], 75.9 [33.3-118.5]; P = .001) and the minimum peri-intubation SpO2 was higher (91.0 ± 3.5 vs 88.0 ± 4.8; mean difference [95% CI], 3.1 [0.4-5.7]; P = .026) in the high-flow nasal oxygenation group compared to the control group. High-flow nasal oxygenation, compared to conventional oxygenation, provided a longer safe apnea time by 76 seconds (40%) and higher minimum SpO2 in morbidly obese patients during anesthesia induction. High-flow oxygenation use should be considered in morbidly obese surgical patients.

Visual impairment in high flow and low flow carotid cavernous fistula

Our aim is to study the varied posterior segment manifestations, level of visual impairment (VI) and its causes in carotid cavernous fistula (CCF) patients. A retrospective study was done, wherein data was obtained from 48 digital subtraction angiogram (DSA) proven CCF patients. CCF was classified according to Barrow et al., based on DSA into type A (high flow) and types B, C and D (low flow). High flow CCF was present in 8 (16.7%) and low flow CCF was present in 42 (83.3%). Compared to low flow group, patients in high flow group were younger and had a history of trauma (p < 0.05). Posterior segment findings ranged from familiar stasis retinopathy and optic neuropathy (both, glaucomatous and ischemic) to uncommon findings of central retinal artery occlusion, Terson syndrome and combined retinal and choroidal detachment. Retinal vein dilatation was the most common finding in both groups. The high flow CCF group had 6 (75%) patients that had VI. This was acute in 4 (50%) patients and delayed in 2 (25%). In the low flow group 10 (23.8%) of patients had delayed VI. The identification of “3 point sign” is a novel finding of this study, not described before. While none of three findings (disc hyperaemia, retinal vein dilatation and intra-retinal haemorrhage) in isolation were predictive of visual loss, but when present together results in visual loss. Posterior segment changes were varied, some are uncommon and can occur in various combinations. “3 point sign” must be identified at the earliest to prevent visual impairment. The incidence of VI in CCF patients is high.

High-Flow Oxygen Therapy to Speed Weaning From Mechanical Ventilation: A Prospective Randomized Study.

High-flow oxygen therapy has been widely adopted, but its use for weaning patients from mechanical ventilation has not been reported. To evaluate whether high-flow oxygen therapy improves the efficiency of weaning patients from mechanical ventilation. In a single-center, prospective study, patients receiving mechanical ventilation were randomly assigned to 1 of 3 groups (T-tube, pressure support ventilation, or high-flow oxygen) during 2-hour spontaneous breathing trials in a 14-day study. Participants were followed up until hospital discharge or death. Of 268 patients included, 90 were assigned to the T-tube group, 96 to the pressure support ventilation group, and 82 to the high-flow oxygen group. The first-day 2-hour spontaneous breathing trial passing rates were higher in the pressure support ventilation and high-flow oxygen groups than in the T-tube group (P < .05). The time needed to pass the spontaneous breathing trial was less in the pressure support ventilation and high-flow oxygen groups than in the T-tube group (P < .05). The reintubation rate was lower and the successful weaning rate on the first day was higher in the high-flow oxygen group than in the T-tube and pressure support ventilation groups (P < .05). During the 14-day study period, the weaning time was less in the high-flow oxygen group than in the T-tube and pressure support ventilation groups (P < .05). High-flow oxygen therapy can reduce the time needed to wean patients from mechanical ventilation by shortening the time needed to pass a spontaneous breathing trial and by decreasing the reintubation rate.

Nasal High-Flow Therapy for Newborn Infants in Special Care Nurseries

BackgroundNasal high-flow therapy is an alternative to nasal continuous positive airway pressure (CPAP) as a means of respiratory support for newborn infants. The efficacy of high-flow therapy in nontertiary special care nurseries is unknown.MethodsWe performed a multicenter, randomized, noninferiority trial involving newborn infants (<24 hours of age; gestational age, ≥31 weeks) in special care nurseries in Australia. Newborn infants with respiratory distress and a birth weight of at least 1200 g were assigned to treatment with either high-flow therapy or CPAP. The primary outcome was treatment failure within 72 hours after randomization. Infants in whom high-flow therapy failed could receive CPAP. Noninferiority was determined by calculating the absolute difference in the risk of the primary outcome, with a noninferiority margin of 10 percentage points.ResultsA total of 754 infants (mean gestational age, 36.9 weeks, and mean birth weight, 2909 g) were included in the primary intention-to-treat analysis. Treatment failure occurred in 78 of 381 infants (20.5%) in the high-flow group and in 38 of 373 infants (10.2%) in the CPAP group (risk difference, 10.3 percentage points; 95% confidence interval [CI], 5.2 to 15.4). In a secondary per-protocol analysis, treatment failure occurred in 49 of 339 infants (14.5%) in the high-flow group and in 27 of 338 infants (8.0%) in the CPAP group (risk difference, 6.5 percentage points; 95% CI, 1.7 to 11.2). The incidences of mechanical ventilation, transfer to a tertiary neonatal intensive care unit, and adverse events did not differ significantly between the groups.ConclusionsNasal high-flow therapy was not shown to be noninferior to CPAP and resulted in a significantly higher incidence of treatment failure than CPAP when used in nontertiary special care nurseries as early respiratory support for newborn infants with respiratory distress. (Funded by the Australian National Health and Medical Research Council and Monash University; HUNTER Australian and New Zealand Clinical Trials Registry number, ACTRN12614001203640.)

Does Universal Bypass before Carotid Artery Occlusion Obviate the Need for Balloon Test Occlusion: Personal Experience with Extracranial-Intracranial Bypass in 23 Patients.

Aim:Carotid artery ligation carries a potential risk of ischemic complications even in patients with good collaterals and adequate cross-circulation. Preoperative assessment through balloon test occlusion (BTO) is technically challenging and not feasible in all patients. We analyze our experience with universal bypass without performing detailed cerebrovascular reserve (CVR) studies in 23 patients before carotid artery ligation.Patients and Methods:This was a retrospective analysis of the case records of 23 patients who underwent cervical carotid artery ligation for various indications since January 2009.Results:The study included 21 patients with cavernous carotid aneurysms, one patient with a large fusiform petrous carotid aneurysm, and one patient with recurrent glomus jugulare encasing the cervical internal carotid artery. The initial 12 patients underwent preoperative BTO with hypotensive challenge. All patients underwent a bypass procedure followed by carotid artery ligation irrespective of the BTO findings. Patients who successfully completed a BTO underwent a low-flow superficial temporal artery to middle cerebral artery bypass. A high-flow extracranial–intracranial bypass using a saphenous vein graft from external carotid artery to middle cerebral artery was done in all patients who either failed the BTO or did not undergo BTO. We had two operative mortalities and one poor outcome. All the other patients had a good recovery with a Glasgow outcome score of 5 at the last follow-up. Graft patency rates were 81.1% in both the low-flow and high-flow groups.Conclusion:Universal high-flow bypass is safe, effective, and should be preferred in all patients before carotid artery ligation. It obviates the need for detailed CVR assessment, especially in centers with limited resources.

LOW-FLOW ANESTHESIA TECHNIQUE REDUCES EMERGENCE AGITATION IN PEDIATRIC PATIENTS UNDERWENT GENERAL ANESTHESIA

Objectives: This study was designed to see the risk factors that contribute to emergence agitation (EA) and also to know the effectiveness of low-flow (LF) anesthesia technique in EA in pediatric patients.&#x0D; Methods: A total of 200 pediatric patients aged 6 months–6 years underwent surgery with general anesthesia were divided into two groups. The high-flow (HF) group was maintained with 5 l fresh gas flow (FGF), and the LF group was maintained with 500 ml FGF. The outcome was measured after the surgery was completed on Face, Legs, Activity, Cry, and Consolability and pediatric anesthesia emergence delirium (PAED) scores. Agitation defined in PAED score ≥10, and no agitation defined in PAED score &lt;10.&#x0D; Results: EA incidence in the HF group was higher compared to the LF group (59.5 vs. 4.7%, p&lt;0.001). HF anesthesia technique was a single risk factor for agitation event, whereas LF anesthesia may prevent EA incidence until up to 92.7%.&#x0D; Conclusion: LF anesthesia reduced agitation incidences. The effectiveness of LF was 92.7% in reducing the incidence of agitation. HF anesthesia was the main risk factor for agitation incidences.

Non-invasive ventilation versus high-flow nasal cannula oxygen therapy with apnoeic oxygenation for preoxygenation before intubation of patients with acute hypoxaemic respiratory failure: a randomised, multicentre, open-label trial

Non-invasive ventilation has never been compared with high-flow oxygen to determine whether it reduces the risk of severe hypoxaemia during intubation. We aimed to determine if preoxygenation with non-invasive ventilation was more efficient than high-flow oxygen in reducing the risk of severe hypoxaemia during intubation. The FLORALI-2 multicentre, open-label trial was done in 28 intensive care units in France. Adult patients undergoing tracheal intubation for acute hypoxaemic respiratory failure (a partial pressure of arterial oxygen [PaO2] to fraction of inspired oxygen [FiO2] ratio of ≤300 mm Hg) were randomly assigned (1:1; block size, four participants) to non-invasive ventilation or high-flow oxygen during preoxygenation, with stratification by PaO2/FiO2 ratio (≤200 mm Hg vs >200 mm Hg). Key exclusion criteria were intubation for cardiac arrest, altered consciousness (defined as a Glasgow coma score of less than eight points), other contraindications to non-invasive ventilation (recent laryngeal, oesophageal, or gastric surgery, and substantial facial fractures), pulse oximetry not available, pregnant or breastfeeding women, and refusal to participate. The primary outcome was the occurrence of severe hypoxaemia (pulse oximetry <80%) during the procedure, assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02668458. Between April 15, 2016, and Jan 8, 2017, 2079 patients were intubated in the 28 participating units, and 322 were enrolled. We excluded five patients with no recorded data, two who withdrew consent or were under legal protection, one who was not intubated, and one who had a cardiac arrest. Of the 313 patients included in the intention-to-treat analysis, 142 were assigned to non-invasive ventilation and 171 to high-flow oxygen therapy. Severe hypoxaemia occurred in 33 (23%) of 142 patients after preoxygenation with non-invasive ventilation and 47 (27%) of 171 with high-flow oxygen (absolute difference -4·2%, 95% CI -13·7 to 5·5; p=0·39). In the 242 patients with moderate-to-severe hypoxaemia (PaO2/FiO2 ≤200 mm Hg), severe hypoxaemia occurred less frequently after preoxygenation with non-invasive ventilation than with high-flow oxygen (28 [24%] of 117 patients vs 44 [35%] of 125; adjusted odds ratio 0·56, 0·32 to 0·99, p=0·0459). Serious adverse events did not differ between treatment groups, with the most common immediate complications being systolic arterial hypotension (70 [49%] patients in the non-invasive ventilation group vs 86 [50%] patients in the high-flow oxygen group) and chest infiltrate on x-ray (28 [20%] vs 33 [19%]), and the most common late complications being death at day 28 (53 [37%] vs 58 [34%]) and ventilator-associated pneumonia during ICU stay (31 [22%] vs 35 [20%]). In patients with acute hypoxaemic respiratory failure, preoxygenation with non-invasive ventilation or high-flow oxygen therapy did not change the risk of severe hypoxaemia. Future research should explore the effect of preoxygenation method in patients with moderate-to-severe hypoxaemia at baseline. French Ministry of Health.

Early nasal high-flow versus Venturi mask oxygen therapy after lung resection: a randomized trial

BackgroundData on high-flow nasal oxygen after thoracic surgery are limited and confined to the comparison with low-flow oxygen. Different from low-flow oxygen, Venturi masks provide higher gas flow at a predetermined fraction of inspired oxygen (FiO2). We conducted a randomized trial to determine whether preemptive high-flow nasal oxygen reduces the incidence of postoperative hypoxemia after lung resection, as compared to Venturi mask oxygen therapy.MethodsIn this single-center, randomized trial conducted in a teaching hospital in Italy, consecutive adult patients undergoing thoracotomic lung resection, who were not on long-term oxygen therapy, were randomly assigned to receive high-flow nasal or Venturi mask oxygen after extubation continuously for two postoperative days. The primary outcome was the incidence of postoperative hypoxemia (i.e., ratio of the partial pressure of arterial oxygen to FiO2 (PaO2/FiO2) lower than 300 mmHg) within four postoperative days.ResultsBetween September 2015 and April 2018, 96 patients were enrolled; 95 patients were analyzed (47 in high-flow group and 48 in Venturi mask group). In both groups, 38 patients (81% in the high-flow group and 79% in the Venturi mask group) developed postoperative hypoxemia, with an unadjusted odds ratio (OR) for the high-flow group of 1.11 [95% confidence interval (CI) 0.41–3] (p = 0.84). No inter-group differences were found in the degree of dyspnea nor in the proportion of patients needing oxygen therapy after treatment discontinuation (OR 1.34 [95% CI 0.60–3]), experiencing pulmonary complications (OR 1.29 [95% CI 0.51–3.25]) or requiring ventilatory support (OR 0.67 [95% CI 0.11–4.18]). Post hoc analyses revealed that PaO2/FiO2 during the study was not different between groups (p = 0.92), but patients receiving high-flow nasal oxygen had lower arterial pressure of carbon dioxide, with a mean inter-group difference of 2 mmHg [95% CI 0.5–3.4] (p = 0.009), and were burdened by a lower risk of postoperative hypercapnia (adjusted OR 0.18 [95% CI 0.06–0.54], p = 0.002).ConclusionsWhen compared to Venturi mask after thoracotomic lung resection, preemptive high-flow nasal oxygen did not reduce the incidence of postoperative hypoxemia nor improved other analyzed outcomes. Further adequately powered investigations in this setting are warranted to establish whether high-flow nasal oxygen may yield clinical benefit on carbon dioxide clearance.Trial registrationClinicalTrials.gov, NCT02544477. Registered 9 September 2015.

Comparison of the Effects of Minimal and High-Flow Anaesthesia on Cerebral Perfusion During Septorhinoplasty.

The aim of this study was to analyse the effects of minimal-and high-flow anaesthesia on cerebral oxygenation during septorhinoplasty with controlled hypotension using near-infrared spectroscopy. Eighty patients scheduled for septorhinoplasty under general anaesthesia with controlled hypotension were randomised into two groups: minimal-flow (MF) or high-flow (HF). Both groups received desflurane anaesthesia to maintain bispectral index values at 40%-50% and 0.25-0.5 μg kg-1 min-1 i.v. remifentanyl infusion to maintain mean arterial blood pressure between 55 and 65 mmHg. The MF group received 5 L min-1 of fresh gas flow for the first 10 mins then the gas flow was reduced 0.4 L min-1. The HF group received 2 L min-1 of fresh gas flow throughout. Haemodynamic parameters and cerebral oxygen saturation were measured. There were no statistical differences in demographic variables, duration of anaesthesia and surgery, time to extubation and proceeding to an Aldrete score of 9. There were no statistical differences in haemodynamic parameters, end-tidal CO2 and cerebral oxygen saturation. The amount of desflurane used in the MF group was significantly lower than that used in the HF group (30.5±9.8 mL vs. 48.5±12.1 mL; p<0.05). MF and HF anaesthesia did not lead to any difference in cerebral oxygen saturation in patients undergoing septorhinoplasty with controlled hypotension. MF anaesthesia may thus be used as safely as HF anaesthesia is.