Noninvasive Ventilation for Preoxygenation during Emergency Intubation.

BACKGROUND: Among critically ill adults undergoing tracheal intubation, hypoxemia increases the risk of cardiac arrest and death. The effect of preoxygenation with noninvasive ventilation, as compared with preoxygenation with an oxygen mask, on the incidence of hypoxemia during tracheal intubation is uncertain. METHODS: In a multicenter, randomized trial conducted at 24 emergency departments and intensive care units in the United States, we randomly assigned critically ill adults (age, ≥18 years) undergoing tracheal intubation to receive preoxygenation with either noninvasive ventilation or an oxygen mask. The primary outcome was hypoxemia during intubation, defined by an oxygen saturation of less than 85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation. RESULTS: Among the 1301 patients enrolled, hypoxemia occurred in 57 of 624 patients (9.1%) in the noninvasive-ventilation group and in 118 of 637 patients (18.5%) in the oxygen-mask group (difference, -9.4 percentage points; 95% confidence interval [CI], -13.2 to -5.6; P<0.001). Cardiac arrest occurred in 1 patient (0.2%) in the noninvasive-ventilation group and in 7 patients (1.1%) in the oxygen-mask group (difference, -0.9 percentage points; 95% CI, -1.8 to -0.1). Aspiration occurred in 6 patients (0.9%) in the noninvasive-ventilation group and in 9 patients (1.4%) in the oxygen-mask group (difference, -0.4 percentage points; 95% CI, -1.6 to 0.7). CONCLUSIONS: Among critically ill adults undergoing tracheal intubation, preoxygenation with noninvasive ventilation resulted in a lower incidence of hypoxemia during intubation than preoxygenation with an oxygen mask. (Funded by the U.S. Department of Defense; PREOXI ClinicalTrials.gov number, NCT05267652.).

Oxygen-Saturation Targets for Critically Ill Adults Receiving Mechanical Ventilation.

BACKGROUND: Invasive mechanical ventilation in critically ill adults involves adjusting the fraction of inspired oxygen to maintain arterial oxygen saturation. The oxygen-saturation target that will optimize clinical outcomes in this patient population remains unknown. METHODS: In a pragmatic, cluster-randomized, cluster-crossover trial conducted in the emergency department and medical intensive care unit at an academic center, we assigned adults who were receiving mechanical ventilation to a lower target for oxygen saturation as measured by pulse oximetry (Spo2) (90%; goal range, 88 to 92%), an intermediate target (94%; goal range, 92 to 96%), or a higher target (98%; goal range, 96 to 100%). The primary outcome was the number of days alive and free of mechanical ventilation (ventilator-free days) through day 28. The secondary outcome was death by day 28, with data censored at hospital discharge. RESULTS: A total of 2541 patients were included in the primary analysis. The median number of ventilator-free days was 20 (interquartile range, 0 to 25) in the lower-target group, 21 (interquartile range, 0 to 25) in the intermediate-target group, and 21 (interquartile range, 0 to 26) in the higher-target group (P = 0.81). In-hospital death by day 28 occurred in 281 of the 808 patients (34.8%) in the lower-target group, 292 of the 859 patients (34.0%) in the intermediate-target group, and 290 of the 874 patients (33.2%) in the higher-target group. The incidences of cardiac arrest, arrhythmia, myocardial infarction, stroke, and pneumothorax were similar in the three groups. CONCLUSIONS: Among critically ill adults receiving invasive mechanical ventilation, the number of ventilator-free days did not differ among groups in which a lower, intermediate, or higher Spo2 target was used. (Supported by the National Heart, Lung, and Blood Institute and others; PILOT ClinicalTrials.gov number, NCT03537937.).

Oxygen Targets in Comatose Survivors of Cardiac Arrest.

BACKGROUND: The appropriate oxygenation target for mechanical ventilation in comatose survivors of out-of-hospital cardiac arrest is unknown. METHODS: In this randomized trial with a 2-by-2 factorial design, we randomly assigned comatose adults with out-of-hospital cardiac arrest in a 1:1 ratio to either a restrictive oxygen target of a partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa (68 to 75 mm Hg) or a liberal oxygen target of a Pao2 of 13 to 14 kPa (98 to 105 mm Hg); patients were also assigned to one of two blood-pressure targets (reported separately). The primary outcome was a composite of death from any cause or hospital discharge with severe disability or coma (Cerebral Performance Category [CPC] of 3 or 4; categories range from 1 to 5, with higher values indicating more severe disability), whichever occurred first within 90 days after randomization. Secondary outcomes were neuron-specific enolase levels at 48 hours, death from any cause, the score on the Montreal Cognitive Assessment (ranging from 0 to 30, with higher scores indicating better cognitive ability), the score on the modified Rankin scale (ranging from 0 to 6, with higher scores indicating greater disability), and the CPC at 90 days. RESULTS: A total of 789 patients underwent randomization. A primary-outcome event occurred in 126 of 394 patients (32.0%) in the restrictive-target group and in 134 of 395 patients (33.9%) in the liberal-target group (hazard ratio, 0.95; 95% confidence interval, 0.75 to 1.21; P = 0.69). At 90 days, death had occurred in 113 patients (28.7%) in the restrictive-target group and in 123 (31.1%) in the liberal-target group. On the CPC, the median category was 1 in the two groups; on the modified Rankin scale, the median score was 2 in the restrictive-target group and 1 in the liberal-target group; and on the Montreal Cognitive Assessment, the median score was 27 in the two groups. At 48 hours, the median neuron-specific enolase level was 17 µg per liter in the restrictive-target group and 18 µg per liter in the liberal-target group. The incidence of adverse events was similar in the two groups. CONCLUSIONS: Targeting of a restrictive or liberal oxygenation strategy in comatose patients after resuscitation for cardiac arrest resulted in a similar incidence of death or severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Lower or Higher Oxygenation Targets for Acute Hypoxemic Respiratory Failure.

BACKGROUND: Patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are treated with supplemental oxygen, but the benefits and harms of different oxygenation targets are unclear. We hypothesized that using a lower target for partial pressure of arterial oxygen (Pao2) would result in lower mortality than using a higher target. METHODS: In this multicenter trial, we randomly assigned 2928 adult patients who had recently been admitted to the ICU (≤12 hours before randomization) and who were receiving at least 10 liters of oxygen per minute in an open system or had a fraction of inspired oxygen of at least 0.50 in a closed system to receive oxygen therapy targeting a Pao2 of either 60 mm Hg (lower-oxygenation group) or 90 mm Hg (higher-oxygenation group) for a maximum of 90 days. The primary outcome was death within 90 days. RESULTS: At 90 days, 618 of 1441 patients (42.9%) in the lower-oxygenation group and 613 of 1447 patients (42.4%) in the higher-oxygenation group had died (adjusted risk ratio, 1.02; 95% confidence interval, 0.94 to 1.11; P = 0.64). At 90 days, there was no significant between-group difference in the percentage of days that patients were alive without life support or in the percentage of days they were alive after hospital discharge. The percentages of patients who had new episodes of shock, myocardial ischemia, ischemic stroke, or intestinal ischemia were similar in the two groups (P = 0.24). CONCLUSIONS: Among adult patients with acute hypoxemic respiratory failure in the ICU, a lower oxygenation target did not result in lower mortality than a higher target at 90 days. (Funded by the Innovation Fund Denmark and others; HOT-ICU ClinicalTrials.gov number, NCT03174002.).

Determinants and Practice Variability of Oxygen Administration during Surgery in the United States: A Retrospective Cohort Study.

BACKGROUND: The best approaches to supplemental oxygen administration during surgery remain unclear, which may contribute to variation in practice. This study aimed to assess determinants of oxygen administration and its variability during surgery. METHODS: Using multivariable linear mixed-effects regression, the study measured the associations between intraoperative fraction of inspired oxygen and patient, procedure, medical center, anesthesiologist, and in-room anesthesia provider factors in surgical cases of 120 min or longer in adult patients who received general anesthesia with tracheal intubation and were admitted to the hospital after surgery between January 2016 and January 2019 at 42 medical centers across the United States participating in the Multicenter Perioperative Outcomes Group data registry. RESULTS: The sample included 367,841 cases (median [25th, 75th] age, 59 [47, 69] yr; 51.1% women; 26.1% treated with nitrous oxide) managed by 3,836 anesthesiologists and 15,381 in-room anesthesia providers. Median (25th, 75th) fraction of inspired oxygen was 0.55 (0.48, 0.61), with 6.9% of cases less than 0.40 and 8.7% greater than 0.90. Numerous patient and procedure factors were statistically associated with increased inspired oxygen, notably advanced American Society of Anesthesiologists classification, heart disease, emergency surgery, and cardiac surgery, but most factors had little clinical significance (less than 1% inspired oxygen change). Overall, patient factors only explained 3.5% (95% CI, 3.5 to 3.5%) of the variability in oxygen administration, and procedure factors 4.4% (95% CI, 4.2 to 4.6%). Anesthesiologist explained 7.7% (95% CI, 7.2 to 8.2%) of the variability in oxygen administration, in-room anesthesia provider 8.1% (95% CI, 7.8 to 8.4%), medical center 23.3% (95% CI, 22.4 to 24.2%), and 53.0% (95% CI, 52.4 to 53.6%) was unexplained. CONCLUSIONS: Among adults undergoing surgery with anesthesia and tracheal intubation, supplemental oxygen administration was variable and appeared arbitrary. Most patient and procedure factors had statistical but minor clinical associations with oxygen administration. Medical center and anesthesia provider explained significantly more variability in oxygen administration than patient or procedure factors.

Effectiveness of preoxygenation strategies: a systematic review and network meta-analysis.

BACKGROUND: Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia. METHODS: We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations. RESULTS: We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position. CONCLUSIONS: Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42022326046.

Occurrence of hyperoxia during iNO treatment for persistent pulmonary hypertension of the newborn: a cohort study.

High concentrations of oxygen are often needed to optimize oxygenation in infants with persistent pulmonary hypertension (PPHN), but this can also increase the risk of hyperoxemia. We determined the occurrence of hyperoxemia in infants treated for PPHN. Medical records of infants ≥ 34 + 0 weeks gestational age (GA) who received inhaled nitric oxide (iNO) were retrospectively reviewed for oxygenation parameters during iNO therapy. Oxygen was manually titrated to target arterial oxygen tension (PaO2) 10-13 kPa and peripheral oxygen saturation (SpO2) 92-98%. The main study outcomes were the incidence and duration of hyperoxemia and hypoxemia and the fraction of inspired oxygen (FiO2). A total of 181 infants were included. The median FiO2 was 0.43 (IQR 0.34-0.56) and the maximum FiO2 was 1.0 in 156/181 (86%) infants, resulting in at least one PaO2 > 13 kPa in 149/181 (82%) infants, of which 46/149 (31%) infants had minimal one PaO2 > 30 kPa. SpO2 was > 98% in 179/181 (99%) infants for 17.7% (8.2-35.6%) of the iNO time. PaO2 < 10 kPa occurred in 160/181 (88%) infants, of which 81/160 (51%) infants had minimal one PaO2 < 6.7 kPa. SpO2 was < 92% in 169/181 (93%) infants for 1.6% (0.5-4.3%) of the iNO time.    Conclusion: While treatment of PPHN is focused on preventing and reversing hypoxemia, hyperoxemia occurs inadvertently in most patients. What is Known: • High concentrations of oxygen are often needed to prevent hypoxemia-induced deterioration of PPHN, but this can also increase the risk of hyperoxemia. • Infants with persistent pulmonary hypertension may be particularly vulnerable to the toxic effects of oxygen, and hyperoxemia could further induce pulmonary vasoconstriction, potentially worsening the condition. What is New: • Hyperoxemia occurs in the majority of infants with PPHN during treatment with iNO. • Infants with PPHN spent a considerably longer period with saturations above the target range compared to saturations below the target range.

Enhancing exercise tolerance in interstitial lung disease with high-flow nasal cannula oxygen therapy: A randomized crossover trial.

BACKGROUND AND OBJECTIVE: Interstitial lung disease (ILD) is characterized by dyspnoea on exertion and exercise-induced hypoxaemia. High-flow nasal cannula (HFNC) therapy reduces the respiratory workload through higher gas flow and oxygen supplementation, which may affect exercise tolerance. This study aimed to examine the effects of oxygen and gas flow rates through HFNC therapy on exercise tolerance in ILD patients. METHODS: We conducted three-treatment crossover study. All ILD patients performed the exercises on room air (ROOM AIR setting: flow, 0 L/min; fraction of inspired oxygen [FiO2], 0.21), HFNC (FLOW setting: flow 40 L/min, FiO2 0.21), and HFNC with oxygen supplementation (FLOW + OXYGEN setting: flow 40 L/min, FiO2 0.6). The primary endpoint was the endurance time, measured using constant-load cycle ergometry exercise testing at a peak work rate of 80%. RESULTS: Twenty-five participants (10 men, 71.2 ± 6.7 years) were enrolled. The increase in exercise duration between the ROOM AIR and FLOW was 46.3 s (95% CI, -6.1 to 98.7; p = 0.083), and the FLOW and FLOW + OXYGEN was 91.5 s (39.1-143.9; p < 0.001). The percutaneous oxygen saturation (SpO2) at rest was significantly higher with the FLOW + OXYGEN setting than with the ROOM AIR and FLOW settings, and the difference persisted during exercise. At equivalent time points during exercise, the SpO2 with the FLOW setting was significantly higher than that with the ROOM AIR setting. CONCLUSION: Oxygen supplementation in HFNC therapy improved exercise tolerance and SpO2. We found that gas flow alone did not improve exercise tolerance, but improved SpO2 during exercise.

Silicone dressing combined with topical oxygen therapy alleviates incontinence-associated dermatitis via NF-κB p65/STAT1 signaling pathway.

BACKGROUND: Incontinence-associated dermatitis (IAD) is a tough problem in clinical settings, not only increasing the risk of complications like catheter-related urinary tract infections and pressure ulcers in elderly and critically ill patients, but also prolonging hospital stays, raising hospital costs, and possibly leading to medical disputes. This study is aimed to evaluate the therapeutic effect of silicone dressing combined with topical oxygen therapy on IAD in a rat model. METHODS: An IAD rat model induced by synthetic urine with trypsin was established. Hematoxylin & eosin staining was carried out to examine skin histology. Using immunofluorescence, the microvessel density in the affected skin tissues was determined. ELISA was performed to measure the concentrations of inflammatory cytokines and angiogenic factors in serum. The mRNA expression of EGF, PDGF, and VEGF was detected via qRT-PCR. Western blotting was employed to determine NF-κB p65/STAT1 pathway-related protein levels. RESULTS: Compared to single therapy, silicone dressing combined with topical oxygen therapy could significantly reduce the severity of IAD, improve skin histology, inhibit inflammation, and promote angiogenesis in IAD rat models. Additionally, the results showed that relatively speaking, the combined therapy suppressed the NF-κB p65/STAT1 signaling pathway more effectively. CONCLUSION: These findings indicated that silicone dressing combined with topical oxygen therapy can alleviate IAD through promoting wound healing and inhibiting inflammation via NF-κB p65/STAT1 signaling pathway in a rat model, which provided a theoretical basis for the prevention and treatment of IAD in clinic.

The effect of high-flow nasal oxygen flow rate on gas exchange in apnoeic patients: a randomised controlled trial.

High-flow nasal oxygen can be administered at induction of anaesthesia for the purposes of pre-oxygenation and apnoeic oxygenation. This intervention is claimed to enhance carbon dioxide elimination during apnoea, but the extent to which this occurs remains poorly quantified. The optimal nasal oxygen flow rate for gas exchange is also unknown. In this study, 114 patients received pre-oxygenation with high-flow nasal oxygen at 50 l.min-1. At the onset of apnoea, patients were allocated randomly to receive one of three nasal oxygen flow rates: 0 l.min-1; 70 l.min-1; or 120 l.min-1. After 4 minutes of apnoea, all oxygen delivery was ceased, tracheal intubation was performed, and oxygen delivery was recommenced when SpO2 was 92%. Mean (SD) PaCO2 rise during the first minute of apnoea was 1.39 (0.39) kPa, 1.41 (0.29) kPa, and 1.26 (0.38) kPa in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, respectively; p = 0.16. During the second, third and fourth minutes of apnoea, mean (SD) rates of rise in PaCO2 were 0.34 (0.08) kPa.min-1, 0.36 (0.06) kPa.min-1 and 0.37 (0.07) kPa.min-1 in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, respectively; p = 0.17. After 4 minutes of apnoea, median (IQR [range]) arterial oxygen partial pressures in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups were 24.5 (18.6-31.4 [12.3-48.3]) kPa; 36.6 (28.1-43.8 [9.8-56.9]) kPa; and 37.6 (26.5-45.4 [11.0-56.6]) kPa, respectively; p < 0.001. Median (IQR [range]) times to desaturate to 92% after the onset of apnoea in the 0 l.min-1, 70 l.min-1 and 120 l.min-1 groups, were 412 (347-509 [190-796]) s; 533 (467-641 [192-958]) s; and 531 (462-681 [326-1007]) s, respectively; p < 0.001. In conclusion, the rate of carbon dioxide accumulation in arterial blood did not differ significantly between apnoeic patients who received high-flow nasal oxygen and those who did not.

Combination of transbronchoscopic oxygen insufflation and a digital chest drainage system in endobronchial occlusion: a hybrid technique for localization of fistula in intractable pneumothorax.

BACKGROUND: The management of intractable secondary pneumothorax poses a considerable challenge as it is often not indicated for surgery owing to the presence of underlying disease and poor general condition. While endobronchial occlusion has been employed as a non-surgical treatment for intractable secondary pneumothorax, its effectiveness is limited by the difficulty of locating the bronchus leading to the fistula using conventional techniques. This report details a case treated with endobronchial occlusion where the combined use of transbronchoscopic oxygen insufflation and a digital chest drainage system enabled location of the bronchus responsible for a prolonged air leak, leading to the successful treatment of intractable secondary pneumothorax. CASE PRESENTATION: An 83-year-old male, previously diagnosed with chronic hypersensitivity pneumonitis and treated with long-term oxygen therapy and oral corticosteroid, was admitted due to a pneumothorax emergency. Owing to a prolonged air leak after thoracic drainage, the patient was deemed at risk of developing an intractable secondary pneumothorax. Due to his poor respiratory condition, endobronchial occlusion with silicone spigots was performed instead of surgery. The location of the bronchus leading to the fistula was unclear on CT imaging. When the bronchoscope was wedged into each subsegmental bronchus and low-flow oxygen was insufflated, a digital chest drainage system detected a significant increase of the air leak only in B5a and B5b, thus identifying the specific location of the bronchus leading to the fistula. With the occlusion of those bronchi using silicone spigots, the air leakage decreased from 200 mL/min to 20 mL/min, and the addition of an autologous blood patch enabled successful removal of the drainage tube. CONCLUSION: The combination of transbronchoscopic oxygen insufflation with a digital chest drainage system can enhance the therapeutic efficacy of endobronchial occlusion by addressing the problems encountered in conventional techniques, where the ability to identify the leaking bronchus is dependent on factors such as the amount of escaping air and the location of the fistula.

High-flow nasal cannula oxygen reduced hypoxemia in patients undergoing gastroscopy under general anesthesia at ultra-high altitude: a randomized controlled trial.

BACKGROUND: Hypoxemia can occur in people at ultra-high altitude (above 3500 m) even at rest, and patients undergoing gastroscopy under general anesthesia have higher risk of hypoxemia. Supplementary oxygen via standard nasal cannula (SNC) is the standard of care for most patients who undergo gastroscopy under general anesthesia, which provides oxygen flow up to 15 L/min. High-flow nasal cannula (HFNC) could deliver oxygen at a rate up to 60 L/min, which is recommended by the American Society of Anesthesiologists Practice Guidelines. We speculated that the benefit with HFNC is more prominent in high-altitude areas, and aimed to compare the incidence of hypoxemia during gastroscopy under general anesthesia at ultra-high altitude with oxygen supply via either HFNC or SNC. METHODS: The trial was registered at at Chinese Clinical Trial Registry (ChiCTR2100045513; date of registration on 18/04/2021). Adult patients undergoing gastroscopy with anesthesia (estimated duration of anesthesia at ≥ 15 min) were randomized at a 1:1 ratio to receive HFNC oxygen or SNC oxygen. The primary outcome was hypoxemia (SpO2 < 90% for any duration). Secondary outcomes included severe hypoxemia (SpO2 < 75% for any duration or SpO2 < 90% but ≥ 75% for ≥ 60 s) and hypotension, as defined by reduction of mean arterial blood pressure by ≥ 25% from the baseline. RESULTS: A total of 262 patients were enrolled: 129 in the HFNC group and 133 in the SNC group. All patients received the designated intervention. Student's t-test, Mann-Whitney U test and χ2 test were employed in the study. The rate of hypoxemia was 9.3% (12/129) in the HFNC group versus 36.8% (49/133) in the SNC group [risk ratio (95% confidence interval): 0.25(0.14-0.45); P < 0.001). The HFNC group also had lower rate of severe hypoxemia [0.0% (0/129) versus 11.3% (15/133); risk ratio (95% confidence interval): 0.03(0.00-0.55); P < 0.001, respectively]. The rate of hypotension did not differ between the 2 groups [22.5% (29/129) in HFNC group versus 21.1% (28/133) in SNC group; risk ratio (95% confidence interval): 1.07(0.67-1.69) ; P = 0.779]. CONCLUSION: HFNC oxygen reduced the incidence of hypoxemia during anesthesia in adult patients undergoing gastroscopy at ultra-high altitude.

Evaluation of oxygen administration in cesarean section under spinal anesthesia via lung ultrasound and the oxygen reserve index.

BACKGROUND: Respiratory functions may be impaired in cesarean section (C/S) delivery performed under spinal anesthesia (SA) and oxygen supplementation may be required. Therefore, we conducted a randomized controlled study aimed to evaluate the effects of different oxygen administrations in pregnant women on the lungs during C/S under SA using ultrasound and oxygen reserve index (ORI). METHODS: We conducted a randomized, controlled, single-center study from May 1, 2021, to March 31, 2022. A total of 90 patients scheduled for C/S under SA were randomly divided into 3 groups. Following the SA, patients in group 0 were treated with room air, in Group 3 were administered 3 L/min O2 with a nasal cannula (NC), in Group 6 were administered 6 L/min O2 with a simple face mask. In addition to routine monitoring, ORI values were measured. Lung aeration was evaluated through the modified lung ultrasound score (LUS) before the procedure (T0), at minute 0 (T1), 20 (T2), and hour 6 (T3) after the procedure, and ∆LUS values were recorded. RESULTS: After SA, the ORI values of Group 3 were higher than Group 0 at all times (p < 0.05), while the intraoperative 1st minute and the 10th, 25th and 40th minutes after delivery (p = 0.001, p = 0.027, p = 0.001, p = 0.019) was higher than Group 6. When the LUS values of each group were compared with the T0 values a decrease was observed in Group 3 and Group 6 (p < 0.001, p = 0.016). While ∆LUS values were always higher in Group 3 than in Group 0, they were higher only in T1 and T2 in Group 6. CONCLUSION: We determined that it would be appropriate to prefer 3 L/min supplemental oxygen therapy with NC in C/S to be performed under SA.

Feasibility of continuous non-invasive delivery of oxygen monitoring in cardiac surgical patients: a proof-of-concept preliminary study.

PURPOSE: Oxygen delivery (DO2) and its monitoring are highlighted to aid postoperative goal directed therapy (GDT) to improve perioperative outcomes such as acute kidney injury (AKI) after high-risk cardiac surgeries associated with multiple morbidities and mortality. However, DO2 monitoring is neither routine nor done postoperatively, and current methods are invasive and only produce intermittent DO2 trends. Hence, we proposed a novel algorithm that simultaneously integrates cardiac output (CO), hemoglobin (Hb) and oxygen saturation (SpO2) from the Edwards Life Sciences ClearSight System® and Masimo SET Pulse CO-Oximetry® to produce a continuous, real-time DO2 trend. METHODS: Our algorithm was built systematically with 4 components - machine interface to draw data with PuTTY, data extraction with parsing, data synchronization, and real-time DO2 presentation using a graphic-user interface. Hb readings were validated. RESULTS: Our algorithm was implemented successfully in 93% (n = 57 out of 61) of our recruited cardiac surgical patients. DO2 trends and AKI were studied. CONCLUSION: We demonstrated a novel proof-of-concept and feasibility of continuous, real-time, non-invasive DO2 monitoring, with each patient serving as their own control. Our study also lays the foundation for future investigations aimed at identifying personalized critical DO2 thresholds and optimizing DO2 as an integral part of GDT to enhance outcomes in perioperative cardiac surgery.

Comparative analysis of neonatal umbilical cord blood gases across various delivery modes at a referral center.

BACKGROUND: This study aimed to address the increasing prevalence of cesarean section and the importance of evaluating newborn health through arterial blood gas analysis. Its primary objective was to compare the umbilical cord blood gas levels in newborns delivered through different delivery methods. METHOD: This retrospective descriptive cross-sectional study included singleton pregnancies with a gestational age between 37 and 42 weeks and infants weighing between 2500 and 4000 g. Newborns with an Apgar score of 7 or higher at 1 and 5 min were included. Umbilical cord blood samples were collected from each newborn for blood gas analysis within 60 min after birth. RESULT: The study included 340 neonates, with 170 born via caesarean section and 170 born through vaginal delivery. No significant differences were observed in Apgar scores between two groups. ABG analysis showed that vaginally born neonates had lower pH (7.24 ± 0.08 vs. 7.27 ± 0.07, P < 0.001), PCO2 (P = 0.015), and HCO3 (P < 0.001). Cesarean section neonates had higher oxygen saturation (P = 0.007) and pressure of oxygen (P < 0.001), and less negative base excess (P < 0.001). In the subgroup analysis, neonates whose mothers received epidural anesthesia had lower pH (7.23 ± 0.07 vs. 7.25 ± 0.08, P = 0.021) and more negative base excess (P = 0.026). Other parameters of ABG did not differ significantly between the groups (P > 0.05). CONCLUSION: It has been proven that the mode of delivery, whether it is vaginal or cesarean, as well as the administration of epidural anesthesia during vaginal delivery, have a significant impact on newborns at birth. Newborns delivered vaginally exhibit metabolic acidosis compared to those delivered via cesarean section. Although these differences are statistically significant, they do not have a notable clinical significance, as the average values of the evaluated parameters in both groups fall within the normal range.

Comparison of preoxygenation using a tight facemask, humidified high-flow nasal oxygen and a standard nasal cannula - a volunteer, randomised, crossover study.

BACKGROUND: Preoxygenation before anaesthesia induction is routinely performed via a tight-fitting facemask or humidified high-flow nasal oxygen. We hypothesised that effective preoxygenation, assessed by end-tidal oxygen (EtO 2 ) levels, can also be performed via a standard nasal cannula. OBJECTIVE: This study compared the efficacy of preoxygenation between a traditional facemask, humidified high-flow nasal oxygen and a standard nasal cannula. DESIGN: A volunteer, randomised, crossover study. SETTING: Karolinska University Hospital, Stockholm. The study was conducted between 2 May and 31 May 2023. PARTICIPANTS: Twenty cardiopulmonary healthy volunteers aged 25-65 years with a BMI <30. INTERVENTIONS: Preoxygenation using a traditional facemask, humidified high-flow nasal oxygen and standard nasal cannula. Volunteers were preoxygenated with all three methods, at various flow rates (10-50 l min -1 ), with open and closed mouths and during vital capacity manoeuvres. MAIN OUTCOME MEASURES: The study's primary outcome compared the efficacy after 3 min of preoxygenation, assessed by EtO 2 levels, between the three methods and various flow rates of preoxygenation. RESULTS: Three methods generated higher EtO 2 levels than others: (i) facemask preoxygenation using normal breathing, (ii) humidified high-flow nasal oxygen, closed-mouth breathing, at 50 l min -1 and (iii) standard nasal cannula, closed-mouth breathing, at 50 l min -1 , and expressed as means (SD): 90% (3), 90% (6) and 88% (5), respectively. Preoxygenation efficacy was greater via the bi-nasal cannulae using closed vs. open mouth breathing as well as with 3 min of normal breathing vs. eight vital capacity breaths. Preoxygenation with a facemask and humidified high-flow nasal oxygen was more comfortable than a standard nasal cannula. CONCLUSION: The efficacy of preoxygenation using a standard nasal cannula at high flow rates is no different to clinically used methods today. The standard nasal cannula provides less comfort but is highly effective and could be an option when alternative methods are unavailable. TRIAL REGISTRATION: Clinicaltrials.gov, NCT05839665.

Effect of nitric oxide delivery via cardiopulmonary bypass circuit on postoperative oxygenation in adults undergoing cardiac surgery (NOCARD trial): a randomised controlled trial.

BACKGROUND: Cardiac surgery involving cardiopulmonary bypass induces a significant systemic inflammatory response, contributing to various postoperative complications, including pulmonary dysfunction, myocardial and kidney injuries. OBJECTIVE: To investigate the effect of Nitric Oxide delivery via the cardiopulmonary bypass circuit on various postoperative outcomes. DESIGN: A prospective, single-centre, double-blinded, randomised controlled trial. SETTING: Rabin Medical Centre, Beilinson Hospital, Israel. PATIENTS: Adult patients scheduled for elective cardiac surgery were randomly allocated to one of the study groups. INTERVENTIONS: For the treatment group, 40 ppm of nitric oxide was delivered via the cardiopulmonary bypass circuit. For the control group, nitric oxide was not delivered. OUTCOME MEASURES: The primary outcome was the incidence of hypoxaemia, defined as a p a O2 /FiO 2 ratio less than 300 within 24 h postoperatively. The secondary outcomes were the incidences of low cardiac output syndrome and acute kidney injury within 72 h postoperatively. RESULTS: Ninety-eight patients were included in the final analysis, with 47 patients allocated to the control group and 51 to the Nitric Oxide group. The Nitric Oxide group exhibited significantly lower hypoxaemia rates at admission to the cardiothoracic intensive care unit (47.1 vs. 68.1%), P  = 0.043. This effect, however, varied in patients with or without baseline hypoxaemia. Patients with baseline hypoxaemia who received nitric oxide exhibited significantly lower hypoxaemia rates (61.1 vs. 93.8%), P  = 0.042, and higher p a O2 /FiO 2 ratios at all time points, F (1,30) = 6.08, P  = 0.019. Conversely, this benefit was not observed in patients without baseline hypoxaemia. No significant differences were observed in the incidence of low cardiac output syndrome or acute kidney injury. No substantial safety concerns were noted, and toxic methaemoglobin levels were not observed. CONCLUSIONS: Patients with baseline hypoxaemia undergoing cardiac surgery and receiving nitric oxide exhibited lower hypoxaemia rates and higher p a O2 /FiO 2 ratios. No significant differences were found regarding postoperative pulmonary complications and overall outcomes. TRIAL REGISTRATION: NCT04807413.

Oxygen concentration titration guided by oxygen reserve index during pediatric laryngeal surgery with high-flow nasal cannula oxygen: a randomized controlled trial.

PURPOSE: The objective of this study was to evaluate whether adjusting the oxygen concentration guided by the Oxygen Reserve Index (ORI) during pediatric laryngeal surgery with High Flow Nasal Cannula Oxygen (HFNO) could achieve postoperative PaO2 close to physiological levels while ensuring adequate oxygenation in surgery. METHODS: Sixty pediatric patients undergoing laryngeal surgery or examination were randomly assigned to two groups. The ORI group received oxygen concentration adjustments every 5 min to maintain a target ORI value of 0.21, whereas the control group did not undergo any adjustments. Postoperative PaO2, time weighted average fraction of inspired oxygen (FiO2), and mean Peripheral Oxygen Saturation (SpO2) were compared between groups. Finally, some analyses were conducted to examine the relationship of ORI with PaO2. RESULTS: In general, the postoperative PaO2 was 164.9 ± 48.8 mmHg in ORI group and 323.0 ± 87.7 mmHg in control group (P < 0.01). The time weighted average FiO2 in the ORI group was 85.9 [81.8-92.7] %. There was no significant difference in mean SpO2 between the two groups (ORI vs. control: 98.4 [97.7-99.2] vs. 98.8 [97.7-99.5]; P = 0.36). According to the analyses, the optimal cut value for ORI was determined to be 0.195 when PaO2 was 150 mmHg. CONCLUSIONS: In pediatric laryngeal surgery with HFNO, reducing oxygen concentration guided by ORI helped achieve postoperative PaO2 levels closer to physiological norms without compromising intra-operative oxygenation.

Addition of Mask to High-flow Nasal Oxygen: A Strategy to Improve Oxygenation in Hypoxemic Respiratory Failure Secondary to COVID-19.

PURPOSE: High-flow nasal cannula (HFNO) reduces the need for invasive mechanical ventilation in COVID-19 patients with hypoxemic-respiratory failure. During HFNO entrainment of room air dilutes the delivered fractional inspiratory oxygen (FiO2), thereby preventing improvement in oxygenation. The placement of a mask over HFNO to improve oxygenation has provided conflicting results. We aimed to determine and compare the effect of placing various mask types over HFNO on oxygen saturation (SPO2). MATERIALS AND METHODS: In this prospective physiological study 40 patients with COVID-19-associated hypoxemic respiratory failure on HFNO with O2 concentration <92% were included. The effect of placing different masks over HFNO on oxygenation, respiratory rate, heart rate, blood pressure, patient comfort, and partial pressure of carbon dioxide level (pCO2) was recorded after a prespecified time interval. RESULTS: We observed a significantly higher mean SPO2 and lower mean respiratory rate on using various study masks over HFNO compared to HFNO alone. On comparing various mask types, the use of N95 masks and nonrebreather (NRB) masks with O2 showed a significant increase in O2 concentration and reduction in respiratory rate compared to surgical mask (SM) and NRB without O2. The proportion of patients who achieved SPO2 of >92% was higher with the use of N95 masks (47.5%) or NRB with O2 (45%) over HFNO compared to SM (35%) and NRB without O2 (35%). No significant change was observed in heart rate, blood pressure, and CO2 level with the use of any mask over HFNO. CONCLUSION: This study demonstrates improvement in oxygenation and reduction in respiratory rate with the use of various masks over HFNO in patients of COVID-19-related hypoxemic-respiratory-failure. Significantly greater benefit was achieved with the use of N95 or NRB with O2 compared to SM or NRB without O2.

Place of high-flow nasal oxygen in nonoperating room anesthesia.

PURPOSE OF REVIEW: This article aims to assess the utility of high-flow nasal oxygen (HFNO) therapy in nonoperating room anesthesia (NORA) settings. RECENT FINDINGS: The number of procedural interventions under deep sedation in NORA is still increasing. Administration of oxygen is recommended to prevent hypoxemia and is usually delivered with standard oxygen through nasal cannula or a face mask. HFNO is a simple alternative with a high warmed humidified flow (ranging from 30 to 70 l/min) with a precise fraction inspired of oxygen (ranging from 21 to 100%). Compared to standard oxygen, HFNO has demonstrated efficacy in reducing the incidence of hypoxemia and the need for airway maneuvers. Research on HFNO has primarily focused on its application in gastrointestinal endoscopy procedures. Yet, it has also shown promising results in various other procedural interventions including bronchoscopy, cardiology, and endovascular procedures. However, the adoption of HFNO prompted considerations regarding cost-effectiveness and environmental impact. SUMMARY: HFNO emerges as a compelling alternative to conventional oxygen delivery methods for preventing hypoxemia during procedural interventions in NORA. However, its utilization should be reserved for patients at moderate-to-high risk to mitigate the impact of cost and environmental factors.