BTS guideline for oxygen use in adults in healthcare and emergency settings

Improving ototoxicity monitoring in patients receiving aminoglycosides using a novel digital approach: a quality improvement project

Aminoglycoside antibiotics cause ototoxicity for which baseline audiometric testing is recommended but often not done. Barriers to successful implementation include limited availability of sound-booths and audiologists. An ototoxicity monitoring programme (OMP) was implemented using tablet-based audiometry (TBA) by non-audiologists.A quality improvement project conducted over 1 year (19 April 2021 to 18 April 2022), using Plan Do Study Act (PDSA) cycles, monitored the adherence to the OMP using Shoebox Standard Edition application on iPads. Barriers to adoption were identified to determine potential solutions for improved adherence. Adult respiratory patients (cystic fibrosis (CF), bronchiectasis, non-tuberculosis mycobacteria (NTM) infection) aged 17-82 years receiving >1 day of intravenous aminoglycosides (IVAGs) at a single tertiary-referral hospital were included. Other reported outcomes were patient characteristics, risk factors associated with abnormal hearing and ototoxic shift.73 patients were tested in the OMP (46 received ≥2 hearing tests) giving an overall adherence rate of 69% after 12 months. Patient identification using referral and reporting systems initially improved adherence from 36% to 88% (p=0.03) during PDSA 1. Barriers to successful adherence were staff availability and COVID-19 infection outbreaks (p=0.057). Older age (p<0.001), higher Body Mass Index (p=0.041), non-CF bronchiectasis (p=0.01), non-CF NTM (p=0.028) and higher Hearing Handicap Inventory for Adults scores (p=0.002) were significantly associated with abnormal baseline hearing. 78% with hearing loss were asymptomatic. Ototoxic shift was associated with gentamicin use compared to amikacin/tobramycin (p=0.027). TBA was associated with high usability in patients ≤50 years old.TBA by non-audiologists was feasible and demonstrated good patient usability, permitting screening of patients within 72 hours of starting IVAG and earlier referrals for formal audiometry. Hearing loss and ototoxicity were detected at earlier stages, enabling more rapid decision-making and treatment modification.

Initiative to improve oxygen prescribing and oxygen delivery to patients in the emergency department of a national referral hospital

Oxygen is the most commonly used drug and is used in the treatment of hypoxaemia. Like any other drug, it should be prescribed appropriately with correct dose via correct device and based on individual needs. Unmonitored and unrestricted use of oxygen can be harmful to patients. The British Thoracic Society has set guidelines about the indication of oxygen use, target goals and how we can titrate oxygen according to the needs of the patients. A quality improvement project was undertaken with the aim of improving the oxygen prescription among the health personnel and improving the appropriate delivery of oxygen to the patients in an emergency department at a national referral hospital in Bhutan for a period of 12 weeks. Our team implemented five Plan-Do-Study-Act cycles based on the data analysis of each cycle, following discussions and after reviewing previous quality improvement projects. The intervention of team education and sensitisation and frequent reminders via posters, emails and group messages were effective in improving the compliance and prescription rates. The doctors' prescription improved from 20% to 82% and nurses' oxygen record from 22% to 83%, and patients receiving oxygen consistent with valid prescription improved from 34% to 86%.

Are we giving too much oxygen to patients at risk of hypercapnia? Real world data from a large teaching hospital

INTRODUCTION

Oxygen guidelines recommend a target saturation range (SpO2 range) of 88-92 % for patients at risk of hypercapnia. Saturations <88 % and saturations >92 % whilst using supplemental oxygen are associated with increased mortality.

METHODS

We audited SpO2 observations of all patients with a prescribed target range of 88-92 % at one hospital over a four-year period.

RESULTS

Of 1,045,958 observations from patients with an oxygen prescription, 107,724 (10.3 %) had a target range of 88-92 % (at risk of hypercapnia). 26,668 of these observations (24.8 %) involved oxygen use. 89.6 % of the SpO2 observations with target SpO2 range 88-92 % were satisfactory with SpO2 ≥88 % breathing air or SpO2 88-92 % breathing oxygen. However, 1.2 % of SpO2 observations for these patients were too low (<88 %). This was commoner in observations involving use of supplemental oxygen (2.2 %) compared with observations on air (0.9 %). Of the SpO2 observations with target SpO2 range 88-92 % which were recorded whilst the patient was receiving supplemental oxygen therapy, 9870 had SpO2 >92 % (over-oxygenated). This represented 9.2 % of all observations for patients with a target range of 88-92 % and 37.0 % of the 26,668 observations involving use of oxygen for these patients. Compared with nasal cannulae, SpO2 observations involving use of simple masks, Venturi masks and humidified oxygen were more commonly outside of the target range.

SUMMARY

We found that excessive oxygen administration was much commoner than insufficient oxygen therapy for hospital patients at risk of hypercapnia. Excessive oxygen use implies an increased risk of harm to these patients, increased cost, and potentially delayed discharges.

Low versus high peripheral oxygen saturation directed oxygen therapy in critically ill patients: a multicenter randomized controlled trial

Whether low peripheral oxygen saturation (SpO2) directed oxygen therapy is associated with lower mortality in critically ill patients needs further exploration. Adult critically ill patients from 11 intensive care units in China were screened. Participants were randomly assigned to the low SpO2 (90%-95%) group or the high SpO2 (≥96%) -group. The primary outcome was 28-day all-cause mortality. The secondary outcomes were hours free from ventilators and from renal replacement therapy (RRT) within 14 days. Note that 857 patients in the low SpO2 group and 849 in the high SpO2 group were included. In the low SpO2 group versus the high SpO2 group, the time-weighted average of the fraction of inspired oxygen (FiO2) was significantly lower (33.5 ± 9.7% vs. 39.6 ± 9.3%, p < 0.001), and so was the time-weighted average of SpO2 (95.9 ± 1.8% vs. 98.0 ± 1.9%, p < 0.001). Within 28 days after randomization, 172 (20.1%) in the low SpO2 group and 193 (22.7%) in the high SpO2 group died (p = 0.180). Ventilator-free time and RRT-free time were not significantly different within 14 days. In critically ill patients, low SpO2directed oxygen therapy did not decrease 28-day mortality, 14-day ventilator-free time, or 14-day RRT-free time.

Perioperative oxygen administration for adults undergoing major noncardiac surgery: a narrative review

Perioperative oxygen administration, a topic under continuous research and debate in anesthesiology, strives to optimize tissue oxygenation while minimizing the risks associated with hyperoxia and hypoxia. This review provides a thorough overview of the current evidence on the application of perioperative oxygen in adult patients undergoing major noncardiac surgery. The review begins by describing the physiological reasoning for supplemental oxygen during the perioperative period and its potential benefits while also focusing on potential hyperoxia risks. This review critically appraises the existing literature on perioperative oxygen administration, encompassing recent clinical trials and meta-analyses, to elucidate its effect on postoperative results. Future research should concentrate on illuminating the optimal oxygen administration strategies to improve patient outcomes and fine-tune perioperative care protocols for adults undergoing major noncardiac surgery. By compiling and analyzing available evidence, this review aims to provide clinicians and researchers with comprehensive knowledge on the role of perioperative oxygen administration in major noncardiac surgery, ultimately guiding clinical practice and future research endeavors.

Individual FiO2 guided by SPO2 prevents hyperoxia and reduces postoperative atelectasis in colorectal surgery: A randomized controlled trial

STUDY OBJECTIVE

To determine whether individualized fraction of inspired oxygen (iFiO2) improves pulmonary atelectasis after elective laparoscopic colorectal surgery relative to 60 % FiO2.

DESIGN

This was a single-center, prospective, randomized study.

SETTING

This study was conducted in a single tertiary care hospital in China.

PATIENTS

A total of 84 eligible inpatients who underwent elective laparoscopic colorectal surgery between August 2021 and May 2022 were included in the study.

INTERVENTIONS

The patients were randomly assigned to receive either a fixed fraction of inspiration oxygen (fFiO2 group) or individualized FiO2 based on physiological SpO2 (iFiO2 group).

MEASUREMENTS

The primary outcome was the lung ultrasound score (LUS) at 30 min after extubation. Secondary outcomes included the length of hospital stay, admission to the intensive care unit, the length of post-anesthetic care unit stay, the ratio of lung capacity on the third day after surgery compared with before surgery, the incidence of nausea and vomiting, and surgical site infections after surgery. Additionally, the airway plate pressure, airway peak pressure, pulmonary dynamic compliance, PaO2, oxygenation index, alveolar-arterial oxygen tension gradient (A-aDO2), and pulmonary shunt fraction (Qs/Qt) were considered.

MAIN RESULTS

The LUS was significantly lowered in the iFiO2 group (5 [4, 7]) compared with the fFiO2 group (8 [4, 10]) (P = 0.03). Based on the criterion for determining atelectasis, 25 patients (62.5 %) in the fFiO2 group experienced significant atelectasis compared with 15 patients (37.5 %) in the iFiO2 group (P = 0.025). At the end of surgery, PaO2, A-aDO2, and Qs/Qt were significantly reduced in patients in the iFiO2 group compared with those in the fFiO2 group.

CONCLUSIONS

The use of iFiO2 during operation significantly reduces the LUS and pulmonary atelectasis in patients undergoing laparoscopic colorectal surgery under general anesthesia.

CLINICAL TRIAL REGISTRATION

ChiCTRT2100049615.

Diagnosis and Management of Acute Pancreatitis

Acute pancreatitis is an inflammatory condition of the exocrine pancreas that is a common indication for hospital admission and has had an increasing incidence in the last few decades. The diagnosis of acute pancreatitis requires the satisfaction of two out of three criteria: (1) abdominal pain radiating to the back, (2) serum lipase or amylase levels three or more times the upper limit of the normal level, and (3) findings indicating pancreatitis obtained via a computed tomography (CT) scan or magnetic resonance imaging (MRI). The different etiologies include gallstones, autoimmune disorders, alcohol abuse, smoking, hypertriglyceridemia, obesity, drugs, and post-endoscope retrograde cholangiopancreatography (ERCP). The initial investigation includes serum amylase and lipase analysis, a lipid panel including triglycerides, analysis of immunoglobulins, a full blood count, electrolyte analysis, a hemoglobin A1c test, a complete metabolic panel, and transabdominal ultrasound. The initial therapy includes oxygen supplementation, the provision of intravenous fluids, pain control, and a nutrition regime. Early oral feeding is encouraged if tolerated; if not, liquid supplement provision or enteral tube feeding within 48 h of admission has shown better outcomes. Some complications of acute pancreatitis are necrosis, infection, insulin resistance leading to diabetes mellitus, and pancreatic exocrine insufficiency requiring enzyme supplementation. Patients need to attend regular follow-ups and abstain from alcohol and smoking (if warranted) to prevent the recurrence of acute pancreatitis. The mortality rate of acute pancreatitis has decreased in the past few decades because of better management skills, but the recent rise in acute pancreatitis episodes is concerning. Sustained endeavors through clinical trials are required to establish a broad variety of drugs that can be used for acute pancreatitis episodes.

Investigation of the Acute Effects of Two Different Preoxygenation Methods on Neurodegenerative Biomarkers in Laparoscopic Cholecystectomy Surgery

Background and Objectives: Oxygen is essential for all living organisms and plays a critical role in anesthesia and intensive care practices. However, the notion that unlimited oxygen therapy is harmless is a misconception. Our study investigates the acute effects of different preoxygenation methods on hemodynamic parameters and neurodegenerative biomarkers in patients undergoing laparoscopic cholecystectomy surgery. Materials and Methods: This prospective, randomized, controlled study included 52 patients undergoing elective laparoscopic cholecystectomy under general anesthesia. Patients were divided into two groups: Group I received standard preoxygenation (100% FiO2 for 3 min), while Group II underwent rapid preoxygenation (eight deep breaths over 30 s to 1 min). Hemodynamic parameters (SAP, DAP, MAP, and SpO2) and neurodegenerative biomarkers (pTau, S100B, NSE, NfL, GFAP) were measured after preoxygenation, after intubation, and at the end of surgery. Results: Group I exhibited a significant increase in levels of pTau, S100B, NSE, and GFAP, indicating higher neuronal and glial cell stress compared to Group II (p < 0.001). No significant increase in NfL levels was observed in either group. Hemodynamic parameters (HR, SAP, DAP, MAP) were significantly higher during and after preoxygenation in Group I, suggesting an increased stress response. Group II showed lower levels of acute neurotoxicity and oxidative stress. Conclusions: Our findings indicate that preoxygenation with 100% FiO2 induces stress in neuronal cells, axons, and glial cells, leading to an increase in neurodegenerative biomarkers. Optimizing preoxygenation strategies is crucial to reduce oxidative stress and improve neurological outcomes for surgical patients.

Bystander cardiopulmonary resuscitation and outcomes of mass cardiac arrests caused by a crowd crush

INTRODUCTION

A crowd crush can lead to respiratory arrest and result in multiple mass cardiac arrests (MCAs), which are often classified as Black Tag in disaster triage. Recently, many laypersons have been commonly trained in compression-only cardiopulmonary resuscitation (CPR) without ventilation support in various communities. This study aims to describe the characteristics of bystander CPR administered and the outcomes of MCAs during the Itaewon crowd crush incident.

METHODS

An observational study was conducted on the CPR characteristics of MCAs during the Halloween Festival in 2022, utilizing two databases: (1) MCAs registered in the Korea Out-of-Hospital Cardiac Arrest Registry (KOHCAR) and (2) MCAs uploaded on social media platforms (Instagram and YouTube), identified through relevant keyword searches. Video clips with a minimum streaming time of 10 s and a clear view of bystander CPR were analyzed. General demographic findings were analyzed using the KOHCAR, while the type of bystander CPR (compression-only CPR with or without rescue breathing) was compared using the social media data.

RESULTS

Of the 218 patients attended by EMS, 119 MCAs were registered in KOHCAR. The mean age of the victims was 24.5 years, with 10 (8.4%) being non-Korean. The median ambulance response time was 59 min. Among the victims, 22 (18.5%) received CPR (19 bybystanders, 2 by first responders, and 1 by a disaster medical assistant team), followed by EMS resuscitation, while 7 (5.9%) received CPR first by the EMS team. The remaining 90 victims (75.6%) were pronounced deceased by EMS providers. Three victims (2.5%) achieved return of spontaneous circulation (ROSC) in the field, and one (0.8%) survived to hospital discharge. From the social media database, 26 video clips containing CPR were identified (14 from 251 clips on Instagram and 12 from 187 on YouTube), excluding duplicates and non-CPR cases. In the 26 video clips containing CPR, a total of 228 bystander CPR cases were identified in the video clips. Of these, 217 (95.2%) involved compression-only CPR, while 11 cases (4.8%) included CPR with rescue breathing.

CONCLUSION

Most MCAs were pronounced deceased, likely due to their classification as Black Tag or delayed response times. Only a small percentage (4.8%) of bystander CPR cases included rescue breathing. An optimized resuscitation protocol for MCAs in crowd crush scenarios should be developed.

Implementation of an advanced practice role for oxygen prescription by physiotherapists in pulmonary rehabilitation: an explanatory sequential mixed-method quality evaluation

BACKGROUND

Physiotherapists play a key role in the administration of supplemental oxygen during physical activity in pulmonary rehabilitation. However, supplemental oxygen requires a medical prescription making processes cumbersome for physiotherapists. This study aimed to implement and evaluate an advanced practice role for physiotherapists (APO2) allowing them to prescribe oxygen during physical activity.

METHODS

Training and certification process for respiratory physiotherapists employed in an inpatient rehabilitation clinic was implemented. A mixed-method approach for retrospective evaluation was used. Quantitative analysis included routine clinical data from oxygen prescriptions, titrations, and exercise capacity. Additionally, healthcare professionals' experiences and perceptions of the new APO2 role was explored using a survey. Qualitative data included interprofessional interviews, survey comments, and data from the critical incidence reporting system.

RESULTS

In 15% of patients during the evaluation period, certified APO2 were involved in oxygen prescription. These patients had more frequent titrations (median 8 [interquartile 6, 10] vs. 5 [4, 8]), prescription adjustments (3 [2, 4] vs. 1 [1, 2]), and narrower oxygen dosage ranges prescribed (2 [1, 3] vs. 4 [3, 4]). No significant difference in exercise capacity was observed and no adverse events reported. Survey data from 19 healthcare professionals and interviews indicated that the specialised expertise of APO2 positively impacts interprofessional collaboration and workflow efficiency.

CONCLUSIONS

Physiotherapy-led oxygen prescription during physical activity in pulmonary rehabilitation is feasible, safe, and perceived as beneficial for the workflow and interprofessional collaboration across healthcare professions.

TRIAL REGISTRATION

According to Swiss law (Human Research Act, Art. 2), ethics approval for the study and informed consent were not required and were waived off. All methods were in accordance with the regulations and guidelines of the Swiss Human Research Act and Swiss ethics law.

Regimen comprising clarithromycin, clofazimine and bedaquiline is more efficacious than monotherapy in a mouse model of chronic Mycobacterium avium lung infection

Mycobacterium avium, a leading non-tuberculous mycobacterium (NTM) pathogen, causes chronic pulmonary infections, particularly in individuals with underlying lung conditions or immunosuppression. Current treatments involve prolonged multi-drug regimens with poor outcomes and significant side effects, highlighting the urgent need for improved therapies. Using a BALB/c mouse model of chronic M. avium pulmonary disease, we evaluated the efficacy of individual antibiotics-clarithromycin, clofazimine, and rifabutin-and combination regimens including clarithromycin+bedaquiline and clarithromycin+clofazimine+bedaquiline. Clarithromycin demonstrated potent bactericidal activity, reducing lung bacterial burden by 2.2 log10 CFU, while clofazimine transitioned from bacteriostatic to bactericidal, achieving a 1.7 log10 CFU reduction. Rifabutin was bacteriostatic against M. avium MAC 101 but ineffective against MAC 104. The triple-drug regimen of clarithromycin+clofazimine+bedaquiline was the most effective, achieving a 3.3 log10 CFU reduction in bacterial load, with 98% clearance within the first week and continued efficacy over eight weeks. Gross pathology confirmed these results, with granulomatous lesions observed only in untreated or rifabutin-treated mice. Combination therapy demonstrated enhanced efficacy compared to monotherapy. The findings underscore the potential of oral clarithromycin+clofazimine+bedaquiline or clarithromycin+clofazimine regimen as a promising therapeutic strategy for M. avium pulmonary disease.

Severe lactic acidosis associated with oral linezolid

We present the case of a patient with cystic fibrosis on long-term oral linezolid treatment for Mycobacteria abscessus lung infection who developed severe linezolid-induced lactic acidosis (LILA) resulting in deranged clotting and pancytopenia. The lactic acidosis was resistant to treatment with intravenous fluid but resolved within 20 hours of initiating continuous veno-venous haemofiltration. An unintended consequence of haemofiltration was that vascular access interfered with effective chest physiotherapy, resulting in worsened lung consolidation requiring prolonged intravenous antibiotic therapy for coexisting Pseudomonas aeruginosa infection. Given the potential mortality and morbidity of LILA, monitoring lactate levels may be clinically important but the optimum timing of monitoring is currently unclear.

Inverse linear association between blood haemoglobin and oxygen saturation accuracy measured by pulse oximetry: a cross-sectional analysis in individuals with COVID-19 infection

BACKGROUND

Pulse oximetry measures oxygen saturation non-invasively by using differential absorption of infrared signals which are dependent on the oxyhaemoglobin:deoxyhaemoglobin ratio. We tested the hypothesis that pulse oximetry error in measurements of blood oxygen saturations may be associated with blood haemoglobin levels.

METHODS

The study design was an observational study of all adult patients admitted to a large teaching hospital with suspected or confirmed COVID-19 infection from February 2020 to December 2021 who had arterial blood gases (ABG) drawn. The pulse oximetry reading was compared with the arterial saturation on the ABG and the measurement error was determined according to the ABG haemoglobin. A secondary analysis was performed among a subset of patients with venous haemoglobins drawn within 24 hours, comparing measurement error between ABG arterial saturation and pulse oximetry readings between those with normal (150 g/L) and low (70 g/L) haemoglobins.

RESULTS

The analysis used 5922 paired oxygen saturations from 3994 patients with contemporaneous haemoglobin measurements by ABG. A 1 g/L decrease in blood haemoglobin was associated with an 0.021% (95% CI: +0.008% to +0.033%) increase in the measurement error (in the direction of a falsely elevated reading.). In the 1086 patients who had had a venous haemoglobin there was a 0.055% (95% CI: +0.020% to +0.090%) increase in the measurement error of oxygen saturation per 1 g/L decrease in blood haemoglobin. The measurement error was thus greater in those with anaemia than in those with normal haemoglobin.

CONCLUSION

As blood haemoglobin decreases, the oxygen saturation measurement derived from a pulse oximeter reads erroneously higher than the true value measured by ABG. While this study was confined to patients with COVID-19, physicians should be aware of this potential discrepancy among all patients with haemorrhage or known anaemia.

Chest compression quality decreases in hypoxic conditions simulating an airliner cabin at cruising altitude: a randomized, controlled, double-blind Manikin Study

Air traveler numbers are predicted to reach 4.0 billion in 2024. Between 1/15,000-50,000 passengers will experience acute medical problems inflight with cardiac arrests requiring cardiopulmonary resuscitation (CPR) accounting for 0.3% of medical emergencies. Hypoxia in airplane cabins could impair oxygenation and physical performance of caregivers. We conducted a randomized controlled, double-blind study to test the hypothesis that hypoxia decreases the effectiveness in performing CPR. We randomized 24 healthcare professionals to two different study arms, each consisting of two conditions: arm (1) 'hypoxia (FiO2 15%, equivalent to 2400 m altitude)' versus 'normoxia'; arm (2) 'hypoxia + supplemental oxygen' versus 'normoxia + supplemental oxygen'. The order of conditions was counterbalanced and a minimum wash-out period of 24 h was granted between conditions. In each condition participants performed a 5-min cardiac compression only CPR (CCO-CPR) using a full-body manikin after one, three and six hours in an altitude chamber. Mixed ANOVAs with post-hoc false-discovery-rate adjusted pairwise comparisons indicated that although compression frequency was maintained, the number of compressions with correct depth was decreased at all times during hypoxia compared to normoxia (all p < 0.002). After 6 h hypoxia exposure, mean compression depth was below the recommended compression depth defined by ERC/AHA guidelines and reduced compared to normoxia (42.4 ± 12.6 mm vs. 54.6 ± 4.3 mm, p < 0.0001). Supplemental oxygen during CCO-CPR in hypoxia prevented the decrease of compression-depth (55.3 ± 3 mm). Extended hypoxia exposure akin to conditions in airplane cabins can reduce quality of chest compressions during CPR. Supplemental oxygen for healthcare providers is an effective countermeasure.

Oxygen therapy and noninvasive respiratory supports in acute hypoxemic respiratory failure: a narrative review

BACKGROUND

This narrative review was written by an expert panel to the members of the jury to help in the development of clinical practice guidelines on oxygen therapy.

RESULTS

According to the expert panel, acute hypoxemic respiratory failure was defined as PaO2 < 60 mm Hg or SpO2 < 90% on room air, or PaO2/FiO2 ≤ 300 mm Hg. Supplemental oxygen should be administered according to the monitoring of SpO2, with the aim at maintaining SpO2 above 92% and below 98%. Noninvasive respiratory supports are generally reserved for the most hypoxemic patients with the aim of relieving dyspnea. High-flow nasal cannula oxygen (HFNC) seems superior to conventional oxygen therapy (COT) as a means of avoiding intubation and may therefore be should probably be used as a first-line noninvasive respiratory support in patients requiring more than 6 L/min of oxygen or PaO2/FiO2 ≤ 200 mm Hg and a respiratory rate above 25 breaths/minute or clinical signs of respiratory distress, but with no benefits on mortality. Continuous positive airway pressure (CPAP) cannot currently be recommended as a first-line noninvasive respiratory support, since its beneficial effects on intubation remain uncertain. Despite older studies favoring noninvasive ventilation (NIV) over COT, recent clinical trials fail to show beneficial effects with NIV compared to HFNC. Therefore, there is no evidence to support the use of NIV or CPAP as first-line treatment if HFNC is available. Clinical trials do not support the hypothesis that noninvasive respiratory supports may lead to late intubation. The potential benefits of awake prone positioning on the risk of intubation in patients with COVID-19 cannot be extrapolated to patients with another etiology.

CONCLUSIONS

Whereas oxygen supplementation should be initiated for patients with acute hypoxemic respiratory failure defined as PaO2 below 60 mm Hg or SpO2 < 90% on room air, HFNC should be the first-line noninvasive respiratory support in patients with PaO2/FiO2 ≤ 200 mm Hg with increased respiratory rate. Further studies are needed to assess the potential benefits of CPAP, NIV through a helmet and awake prone position in patients with acute hypoxemic respiratory failure not related to COVID-19.

An Innovative Study Focused on Reducing Unnecessary Oxygen Exposure in Pediatric Patients

PURPOSE

In the perioperative period, fractional-inspired oxygen is used at values up to 80% to stay within the safe range, even for a short time. A clear value for the safe range has not been specified, and therefore, clinicians prefer a high oxygen value. This study aims to reduce unnecessary oxygen exposure in pediatrice patients and to provide the optimum fractional inspired oxygen value.

DESIGN

The study was designed as a prospective randomized controlled study, including 139 patients aged 1 to 8 years without comorbidity.

METHODS

Three groups were formed by adjusting the fractional inspired oxygen to 30%, 50%, or 80% intraoperatively. In the intraoperative period, a strict inspired oxygen protocol (hypoxemia threshold was SpO2 < 90) and oxygen reserve index, fractional expired oxygen value, and peripheral oxygen saturation were used to maintain the balance of hypoxemia and hyperoxemia.

FINDINGS

One hundred and nine children were included. The mean oxygen reserve index was significantly lower in the 30% group than in the other groups (0.09 ± 0.05, P < .0001). The mean arterial pressure in the 30% group was significantly lower than the 80% group but within the normal range (78 ± 6 mmHg, P < .003). There was no significant difference between the groups regarding delirium and pain in the recovery unit.

CONCLUSIONS

Due to the known and unknown harmful effects of unnecessary oxygen exposure, it may be time to use optimal oxygen and to fear unnecessary oxygen, not less oxygen. As the next step, we think studies should be conducted with patient groups with lower oxygen concentrations (eg, %21 vs %24 vs %30), more patients, and arterial blood gas monitoring.

Improving Compliance With Valid Oxygen Prescriptions for Surgical Inpatients in a District General Hospital: A Single-Centre Quality Improvement Study

Introduction Medical oxygen is a drug and, as such, must be correctly prescribed according to British Thoracic Society (BTS) guidelines. These guidelines state that a valid prescription must include a target oxygen saturation range, and that all inpatients should have a valid oxygen prescription. A 2008 BTS audit revealed only 32% of patients receiving oxygen had valid prescriptions, and a 2015 re-audit showed improvement to 57.5%, still below the national 95% target. Unregulated oxygen administration can lead to complications such as hypoxia, hyperoxia, and increased healthcare costs. Our quality improvement project (QIP) aimed to improve adherence to BTS guidelines on two general surgical wards at Royal Blackburn Teaching Hospital, aiming for complete adherence. Methods A quality improvement study was conducted using electronic patient records (EPRs). In the baseline audit, data was collected on patients over a one-week period. Thirty-three patients were included, with information on age, oxygen prescriptions, and Chronic Obstructive Pulmonary Disease (COPD) status recorded. Four interventions were then implemented: the addition of reminders to handover sheets, visual prompts around the ward, announcements during nursing huddles, and WhatsApp reminders to the ward doctors. A re-audit was conducted after the interventions, including 31 patients, and data was compared using the Chi-squared test. Results In the baseline audit, 18% of patients had oxygen prescribed. Following the interventions, this rose to 54.8% (χ²(1, N=64) = 9.3, p < 0.01), and as such, was statistically significant. Among patients requiring oxygen, compliance improved from 0% to 90.9%.  Discussion The interventions significantly improved oxygen prescription compliance, demonstrating the effectiveness of simple, targeted measures. The inclusion of the multidisciplinary team (MDT) was crucial, as both nurses and doctors play essential roles in oxygen delivery. However, compliance remained below the BTS target of 100%. Limitations include not assessing the impact of individual interventions and analyzing only two points in time. Future audits should focus on targeting prescribers early in admissions and integrate electronic systems for automated prescription prompts. Spot audits could help ensure long-term success. Conclusion This QIP improved compliance with BTS oxygen prescribing guidelines at Royal Blackburn Teaching Hospital, from 18% to 54.8%. Engaging the MDT and using reminders increased compliance, but further efforts are needed to achieve the 100% target. Future interventions should focus on EPR integration, ongoing education, and further audit cycles for sustained improvement.

Effects of Oxygenation Targets on Mortality in Critically Ill Patients in Intensive Care Units: A Systematic Review and Meta-Analysis

BACKGROUND

The effects of oxygenation targets (partial pressure of arterial oxygen [Pa o2 ], arterial oxygen saturation [Sa o2 ]/peripheral oxygen saturation [Sp o2 ], or inspiratory oxygen concentration [Fi o2 ] on clinical outcomes in critically ill patients remains controversial. We reviewed the existing literature to assess the effects of lower and higher oxygenation targets on the mortality rates of critically ill intensive care unit (ICU) patients.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched from their dates of inception to December 31, 2022, for randomized controlled trials (RCTs) comparing lower and higher oxygenation targets for critically ill patients ≥18 years of age undergoing mechanical ventilation, nasal cannula, oxygen mask, or high-flow oxygen therapy in the ICU. Data extraction was conducted independently, and RoB 2.0 software was used to evaluate the quality of each RCT. A random-effects model was used for the meta-analysis to calculate the relative risk (RR). We used the I 2 statistic as a measure of statistical heterogeneity. Certainty of evidence was assessed according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines.

RESULTS

We included 12 studies with a total of 7416 patients participating in RCTs. Oxygenation targets were extremely heterogeneous between studies. The meta-analysis found no differences in mortality between lower and higher oxygenation targets for critically ill ICU patients (relative risk [RR], 1.00; 95% confidence interval [CI], 0.93-1.09; moderate certainty). The incidence of serious adverse events (RR, 0.93; 95% CI, 0.85-1.00; high certainty), mechanical ventilation-free days through day 28 (mean difference [MD], -0.05; 95%CI, -1.23 to 1.13; low certainty), the number of patients requiring renal replacement therapy (RRT) (RR, 0.96; 95% CI, 0.84-1.10; low certainty), and ICU length of stay (MD, 1.05; 95% CI, -0.04 to 2.13; very low certainty) also did not differ among patients with lower or higher oxygenation targets.

CONCLUSIONS

Critically ill ICU patients ≥18 years of age managed with lower and higher oxygenation targets did not differ in terms of mortality, RRT need, mechanical ventilation-free days through day 28, or ICU length of stay. However, due to considerable heterogeneity between specific targets in individual studies, no conclusion can be drawn regarding the effect of oxygenation targets on ICU outcomes.

Implementing Oxygen Therapy in Medical Wards-A Scoping Review to Understand Health Services Protocols and Procedures

Background/Objectives: Conventional oxygen therapy (COT) is the cornerstone of management for hypoxaemia associated with acute respiratory failure (ARF) in wards. COT implementation guidance is provided in local health guidance documents (LHGDs). This study aimed to identify ward-delivered adult COT implementation LHGDs in Australian health services and assess their content and accuracy. Methods: A scoping review was conducted on 1 May 2022 and updated on 19 December 2023 to identify public health services COT LHGDs. Data were extracted and analysed regarding COT initiation, monitoring, maintenance and weaning, and management of clinical deterioration. Results: Thirty-seven included LHGDs, and eleven referenced the Australian COT guidelines. A definition in the LHGDs for hypoxaemia is that any oxygen saturation (SpO2) or arterial blood gas (ABG) is rare. None required ABG prior to COT initiation. Twenty-nine provided target SpO2 aims for initiation and maintenance. Fifteen did not specify the criteria for clinical review. Nine LHGDs provided guidance on weaning. Conclusions: There was considerable variation in the structure and content of COT LHGDs in Australian health services. Variations and limited guideline concordance of LHGDs may impact the quality and safety of health care. Considerations for future research include the development and implementation of standardised core LHGD recommendations for COT, as well as conducting a national oxygen audit to better measure and benchmark the safety and quality of care.

Effects of moderate alcohol consumption and hypobaric hypoxia: implications for passengers' sleep, oxygen saturation and heart rate on long-haul flights

BACKGROUND

Passengers on long-haul flights frequently consume alcohol. Inflight sleep exacerbates the fall in blood oxygen saturation (SpO2) caused by the decreased oxygen partial pressure in the cabin. We investigated the combined influence of alcohol and hypobaric hypoxia on sleep, SpO2 and heart rate.

METHODS

Two groups of healthy individuals spent either two nights with a 4-hour sleep opportunity (00:00-04:00 hours) in the sleep laboratory (n=23; 53 m above sea level) or in the altitude chamber (n=17; 753 hPa corresponding to 2438 m above sea level, hypobaric condition). Participants consumed alcohol before one of the nights (mean±SE blood alcohol concentration 0.043±0.003%). The order of the nights was counterbalanced. Two 8-hour recovery nights (23:00-07:00 hours) were scheduled between conditions. Polysomnography, SpO2 and heart rate were recorded.

RESULTS

The combined exposure to alcohol and hypobaric condition decreased SpO2 to a median (25th/75th percentile) of 85.32% (82.86/85.93) and increased heart rate to a median (25th/75th percentile) of 87.73 bpm (85.89/93.86) during sleep compared with 88.07% (86.50/88.49) and 72.90 bpm (70.90/78.17), respectively, in the non-alcohol hypobaric condition, 94.97% (94.59/95.33) and 76.97 bpm (65.17/79.52), respectively, in the alcohol condition and 95.88% (95.72/96.36) and 63.74 bpm (55.55/70.98), respectively, in the non-alcohol condition of the sleep laboratory group (all p<0.0001). Under the combined exposure SpO2 was 201.18 min (188.08/214.42) below the clinical hypoxia threshold of 90% SpO2 compared with 173.28 min (133.25/199.03) in the hypobaric condition and 0 min (0/0) in both sleep laboratory conditions. Deep sleep (N3) was reduced to 46.50 min (39.00/57.00) under the combined exposure compared with both sleep laboratory conditions (alcohol: 84.00 min (62.25/92.75); non-alcohol: 67.50 min (58.50/87.75); both p<0.003).

CONCLUSIONS

The combination of alcohol and inflight hypobaric hypoxia reduced sleep quality, challenged the cardiovascular system and led to extended duration of hypoxaemia (SpO2 <90%).

Oxygen therapy in acute hypoxemic respiratory failure: guidelines from the SRLF-SFMU consensus conference

INTRODUCTION

Although largely used, the place of oxygen therapy and its devices in patients with acute hypoxemic respiratory failure (ARF) deserves to be clarified. The French Intensive Care Society (Société de Réanimation de Langue Française, SRLF) and the French Emergency Medicine Society (Société Française de Médecine d'Urgence, SFMU) organized a consensus conference on oxygen therapy in ARF (excluding acute cardiogenic pulmonary oedema and hypercapnic exacerbation of chronic obstructive diseases) in December 2023.

METHODS

A committee without any conflict of interest (CoI) with the subject defined 7 generic questions and drew up a list of sub questions according to the population, intervention, comparison and outcomes (PICO) model. An independent work group reviewed the literature using predefined keywords. The quality of the data was assessed using the GRADE methodology. Fifteen experts in the field from both societies proposed their own answers in a public session and answered questions from the jury (a panel of 16 critical-care and emergency medicine physicians, nurses and physiotherapists without any CoI) and the public. The jury then met alone for 48 h to write its recommendations.

RESULTS

The jury provided 22 statements answering 11 questions: in patients with ARF (1) What are the criteria for initiating oxygen therapy? (2) What are the targets of oxygen saturation? (3) What is the role of blood gas analysis? (4) When should an arterial catheter be inserted? (5) Should standard oxygen therapy, high-flow nasal cannula oxygen therapy (HFNC) or continuous positive airway pressure (CPAP) be preferred? (6) What are the indications for non-invasive ventilation (NIV)? (7) What are the indications for invasive mechanical ventilation? (8) Should awake prone position be used? (9) What is the role of physiotherapy? (10) Which criteria necessarily lead to ICU admission? (11) Which oxygenation device should be preferred for patients for whom a do-not-intubate decision has been made?

CONCLUSION

These recommendations should optimize the use of oxygen during ARF.

Cyclosporin A as an Add-On Therapy to a Corticosteroid-Based Background Treatment in Patients with COVID-19: A Multicenter, Randomized Clinical Trial

Background: In susceptible hosts, SARS-CoV2-induced hyperinflammation accounts for an increased mortality. The search of adjuvant immunomodulatory therapies has been ongoing ever since the pandemic outbreak. Aim: Our purpose was to evaluate the efficacy of cyclosporin A (CsA) as an add-on therapy to the standard of care (SoC) in patients with severe COVID-19 pneumonia. Methods: We conducted a randomized clinical trial in patients admitted to eight Spanish tertiary hospitals. Patients were stratified into two severity categories and randomized in a 1:1 ratio to receive a corticosteroid-based standard therapy with or without CsA. The primary endpoint was FiO2 recovery by Day 12 without relapses. Results: 109 patients were included and randomized, and 98 of them considered for the mITT population (51 assigned to the CsA + SoC group and 47 to the SoC group). A total of 35 (68.6%) patients from the CsA + SoC group and 32 (71.1%) patients from the SoC group reached the primary endpoint in the mITT analysis. No differences were found after stratification into age groups, in the severity level at admission, or in a combination of both. Overall, the time to FiO2 normalization was 7.4 days vs. 7.9 days in the experimental and control groups, respectively. Global mortality was 8.2%. Severe adverse events were uncommon and equally distributed between arms. Conclusion: The addition of CsA did not show differences over a corticosteroid-based treatment in the clinical course of the included patients. A better identification of candidates who will benefit from receiving immunomodulatory drugs is necessary in future studies.

Predictors of high-flow nasal cannula failure in COVID-19 patients in a northern Peruvian hospital

OBJECTIVES

To determine predictors of high-flow nasal cannula (HFNC) failure in COVID-19 patients in a hospital in northern Peru.

METHODOLOGY

A retrospective cohort study was conducted during the months of March and May 2021. Data collection was based on a follow-up of 156 hospitalized patients with a diagnosis of COVID-19 who were users of HFNC. Epidemiological factors and clinical outcomes of treatment were analyzed from medical records. Epidemiological, analytical, and HFNC use-related characteristics were described using measures of absolute and relative frequencies, measures of central tendency, and dispersion. A multivariate Poisson regression analysis with robust variance and a 95% confidence interval was performed.

RESULTS

We found that age, SpO2/FiO2, work of breathing (WOB scale) at admission, degree of involvement, type of infiltrate on CT scan, lymphocytes, c-reactive protein, and D-dimer were significantly associated with failure of HFNC (p < 0.05). In addition, the WOB scale, PaO2/FiO2, SaO2/FiO2, and ROX index were variables that presented statistical significance (p < 0.0001). In the multivariate analysis model, a risk of failure of HFNC was determined with age > = 60 years [RRa 1.39 (1.05-1.85)] and PaO2/FiO2 score less than 100 [Rra 1.65 (0.99-2.76)].

CONCLUSIONS

Predictors to failure of HFNC are age older than 60 years and minimally significantly lower PaO2/FiO2 than 100.

Efflux pumps and membrane permeability contribute to intrinsic antibiotic resistance in Mycobacterium abscessus

Mycobacterium abscessus is a pulmonary pathogen that exhibits intrinsic resistance to antibiotics, but the factors driving this resistance are incompletely understood. Insufficient intracellular drug accumulation could explain broad-spectrum resistance, but whether antibiotics fail to accumulate in M. abscessus and the mechanisms required for drug exclusion remain poorly understood. We measured antibiotic accumulation in M. abscessus using mass spectrometry and found a wide range of drug accumulation across clinically relevant antibiotics. Of these compounds, linezolid accumulates the least, suggesting that inadequate uptake impacts its efficacy. We utilized transposon mutagenesis screening to identify genes that cause linezolid resistance and found multiple transporters that promote membrane permeability or efflux, including an uncharacterized, M. abscessus-specific protein that effluxes linezolid and several chemically related antibiotics. This demonstrates that membrane permeability and drug efflux are critical mechanisms of antibiotic resistance in M. abscessus and suggests that targeting membrane transporters could potentiate the efficacy of certain antibiotics.

Lower or higher oxygenation targets in the intensive care unit: an individual patient data meta-analysis

PURPOSE

Optimal oxygenation targets for patients with acute hypoxemic respiratory failure in the intensive care unit (ICU) are not clearly defined due to substantial variability in design of previous trials. This study aimed to perform a pre-specified individual patient data meta-analysis of the Handling Oxygenation Targets in the ICU (HOT-ICU) and the Handling Oxygenation Targets in coronavirus disease 2019 (COVID-19) (HOT-COVID) trials to compare targeting a partial pressure of arterial oxygen (PaO2) of 8-12 kPa in adult ICU patients, assessing both benefits and harms.

METHODS

We assessed 90-day all-cause mortality and days alive without life support in 90 days using a generalised mixed model. Heterogeneity of treatment effects (HTE) was evaluated in 14 subgroups, and results graded using the Instrument to assess the Credibility of Effect Modification Analyses (ICEMAN).

RESULTS

At 90 days, mortality was 40.4% (724/1792) in the 8 kPa group and 40.9% (733/1793) in the 12 kPa group (risk ratio, 0.99; 95% confidence interval [CI] 0.92-1.07; P = 0.80). No difference was observed in number of days alive without life support. Subgroup analyses indicated more days alive without life support in COVID-19 patients targeting 8 kPa (P = 0.04) (moderate credibility), and lower mortality (P = 0.03) and more days alive without life support (P = 0.02) in cancer-patients targeting 12 kPa (low credibility).

CONCLUSION

This study reported no overall differences comparing a PaO2 target of 8-12 kPa on mortality or days alive without life support in 90 days. Subgroup analyses suggested HTE in patients with COVID-19 (moderate credibility) and cancer (low credibility).

Research progress on high-concentration oxygen therapy after cerebral hemorrhage

Recently, the role of high-concentration oxygen therapy in cerebral hemorrhage has been extensively discussed. This review describes the research progress in high-concentration oxygen therapy after cerebral hemorrhage. High-concentration oxygen therapy can be classified into two treatment methods: hyperbaric and normobaric high-concentration oxygen therapy. Several studies have reported that high-concentration oxygen therapy uses the pathological mechanisms of secondary ischemia and hypoxia after cerebral hemorrhage as an entry point to improve cerebral oxygenation, metabolic rate, cerebral edema, intracranial pressure, and oxidative stress. We also elucidate the mechanisms by which molecules such as Hypoxia-inducible factor 1-alpha (HIF-1α), vascular endothelial growth factor, and erythropoietin (EPO) may play a role in oxygen therapy. Although people are concerned about the toxicity of hyperoxia, combined with relevant literature, the evidence discussed in this article suggests that as long as the duration, concentration, pressure, and treatment interval of patients with cerebral hemorrhage are properly understood and oxygen is administered within the treatment window, it can be effective to avoid hyperoxic oxygen toxicity. Combined with the latest research, we believe that high-concentration oxygen therapy plays an important positive role in injuries and outcomes after cerebral hemorrhage, and we recommend expanding the use of normal-pressure high-concentration oxygen therapy for cerebral hemorrhage.

Growing from common ground: nontuberculous mycobacteria and bronchiectasis

Bronchiectasis and nontuberculous mycobacteria (NTM) are intricately intertwined, with NTM capable of being both a cause and consequence of bronchiectatic disease. This narrative review focuses on the common ground of bronchiectasis and NTM pulmonary disease (NTM-PD) in terms of diagnostic approach, underlying risk factors and treatment strategies. NTM-PD diagnosis relies on a combination of clinical, radiological and microbiological criteria. Although their epidemiology is complicated by detection and reporting biases, the prevalence and pathogenicity of NTM species vary geographically, with Mycobacterium avium complex and Mycobacterium abscessus subspecies most frequently isolated in bronchiectasis-associated NTM-PD. Diagnosis of nodular bronchiectatic NTM-PD should prompt investigation of host factors, including disorders of mucociliary clearance, connective tissue diseases and immunodeficiencies, either genetic or acquired. Treatment of NTM-PD in bronchiectasis involves a multidisciplinary approach and considers the (sub)species involved, disease severity and comorbidities. Current guideline-based antimicrobial treatment of NTM-PD is considered long, cumbersome and unsatisfying in terms of outcomes. Novel treatment regimens and strategies are being explored, including rifampicin-free regimens and inclusion of clofazimine and inhaled antibiotics. Host-directed therapies, such as immunomodulators and cytokine-based therapies, might enhance antimycobacterial immune responses. Optimising supportive care, as well as pathogen- and host-directed strategies, is crucial, highlighting the need for personalised approaches tailored to individual patient needs. Further research is warranted to elucidate the complex interplay between host and mycobacterial factors, informing more effective management strategies.

Treating sleep-disordered breathing of idiopathic pulmonary fibrosis patients with CPAP and nocturnal oxygen treatment. A pilot study : Sleep-disordered breathing treatment in IPF

INTRODUCTION

Sleep-disordered breathing (SDB) is a major comorbidity in idiopathic pulmonary fibrosis (IPF) and is associated with a poor outcome. There is a lack of knowledge regarding the impact of SDB treatment on IPF. We assessed at one year: (1) the effect of CPAP and/or nocturnal oxygen therapy on IPF regarding lung function, blood mediators, and quality of life; (2) adherence to SDB treatment and SDB changes.

METHODOLOGY

This is a prospective study of consecutive newly diagnosed IPF patients initiating anti-fibrotic treatment. Lung function, polysomnography, blood tests and quality of life questionnaires were performed at inclusion and after one year. Patients were classified as obstructive sleep apnoea (OSA), central sleep apnoea (CSA), and sleep-sustained hypoxemia (SSH). SDB therapy (CPAP and/or nocturnal oxygen therapy) was initiated if needed.

RESULTS

Fifty patients were enrolled (36% had OSA, 22% CSA, and 12% SSH). CPAP was started in 54% of patients and nocturnal oxygen therapy in 16%. At one-year, polysomnography found improved parameters, though 17% of patients had to add nocturnal oxygen therapy or CPAP, while 33% presented SDB onset at this second polysomnography. CPAP compliance at one year was 6.74 h/night (SD 0.74). After one year, matrix metalloproteinase-1 decreased in OSA and CSA (p = 0.029; p = 0.027), C-reactive protein in OSA (p = 0.045), and surfactant protein D in CSA group (p = 0.074). There was no significant change in lung function.

CONCLUSIONS

Treatment of SBD with CPAP and NOT can be well tolerated with a high compliance. IPF patients may exhibit SDB progression and require periodic re-assessment. Further studies to evaluate the impact of SDB treatment on lung function and serological mediators are needed.

Automated oxygen titration with non-invasive ventilation in hypoxaemic adults with cardiorespiratory disease: a randomised cross-over trial

BACKGROUND

Closed-loop oxygen control systems automatically adjust the fraction of inspired oxygen (FiO2) to maintain oxygen saturation (SpO2) within a predetermined target range. Their performance with low and high-flow oxygen therapies, but not with non-invasive ventilation, has been established. We compared the effect of automated oxygen on achieving and maintaining a target SpO2 range with nasal high flow (NHF), bilevel positive airway pressure (bilevel) and continuous positive airway pressure (CPAP), in stable hypoxaemic patients with chronic cardiorespiratory disease.

METHODS

In this open-label, three-way cross-over trial, participants with resting hypoxaemia (n=12) received each of NHF, bilevel and CPAP treatments, in random order, with automated oxygen titrated for 10 min, followed by 36 min of standardised manual oxygen adjustments. The primary outcome was the time taken to reach target SpO2 range (92%-96%). Secondary outcomes included time spent within target range and physiological responses to automated and manual oxygen adjustments.

RESULTS

Two participants were randomised to each of six possible treatment orders. During automated oxygen control (n=12), the mean (±SD) time to reach target range was 114.8 (±87.9), 56.6 (±47.7) and 67.3 (±61) seconds for NHF, bilevel and CPAP, respectively, mean difference 58.3 (95% CI 25.0 to 91.5; p=0.002) and 47.5 (95% CI 14.3 to 80.7; p=0.007) seconds for bilevel and CPAP versus NHF, respectively. Proportions of time spent within target range were 68.5% (±16.3), 65.6% (±28.7) and 74.7% (±22.6) for NHF, bilevel and CPAP, respectively.Manually increasing, then decreasing, the FiO2 resulted in similar increases and then decreases in SpO2 and transcutaneous carbon dioxide (PtCO2) with NHF, bilevel and CPAP.

CONCLUSION

The target SpO2 range was achieved more quickly when automated oxygen control was initiated with bilevel and CPAP compared with NHF while time spent within the range across the three therapies was similar. Manually changing the FiO2 had similar effects on SpO2 and PtCO2 across each of the three therapies.

TRIAL REGISTRATION NUMBER

ACTRN12622000433707.

Metformin-associated lactic acidosis: A mini review of pathophysiology, diagnosis and management in critically ill patients

Metformin is a common diabetes drug that may reduce lactate clearance by inhibiting mitochondrial oxidative phosphorylation, leading to metformin-associated lactic acidosis (MALA). As diabetes mellitus is a common chronic metabolic condition found in critically ill patients, pre-existing metformin use can often be found in critically ill patients admitted to the intensive care unit or the high dependency unit. The aim of this narrative mini review is therefore to update clinicians about MALA, and to provide a practical approach to its diagnosis and treatment. MALA in critically ill patients may be suspected in a patient who has received metformin and who has a high anion gap metabolic acidosis, and confirmed when lactate exceeds 5 mmol/L. Risk factors include those that reduce renal elimination of metformin (renal impairment from any cause, histamine-2 receptor antagonists, ribociclib) and excessive alcohol consumption (as ethanol oxidation consumes nicotinamide adenine dinucleotides that are also required for lactate metabolism). Treatment of MALA involves immediate cessation of metformin, supportive management, treating other concurrent causes of lactic acidosis like sepsis, and treating any coexisting diabetic ketoacidosis. Severe MALA requires extracorporeal removal of metformin with either intermittent hemodialysis or continuous kidney replacement therapy. The optimal time to restart metformin has not been well-studied. It is nonetheless reasonable to first ensure that lactic acidosis has resolved, and then recheck the kidney function post-recovery from critical illness, ensuring that the estimated glomerular filtration rate is 30 mL/min/1.73 m2 or better before restarting metformin.

Hyperoxemia among Pediatric Intensive Care Unit Patients Receiving Oxygen Therapy

Supratherapeutic oxygen levels consistently cause oxygen toxicity in the lungs and other organs. The prevalence and severity of hyperoxemia among pediatric intensive care unit (PICU) patients remain unknown. This was the first study to examine the prevalence and duration of hyperoxemia in PICU patients receiving oxygen therapy. This is a retrospective chart review. This was performed in a setting of 36-bed PICU in a quaternary-care children's hospital. All the patients were children aged <18 years, admitted to the PICU for ≥24 hours, receiving oxygen therapy for ≥12 hours who had at least one arterial blood gas during this time. There was no intervention. Of 5,251 patients admitted to the PICU, 614 were included in the study. On average, these patients received oxygen therapy for 91% of their time in the PICU and remained hyperoxemic, as measured by pulse oximetry, for 65% of their time on oxygen therapy. Patients on oxygen therapy remained hyperoxemic for a median of 38 hours per patient and only 1.1% of patients did not experience any hyperoxemia. Most of the time (87.5%) patients received oxygen therapy through a fraction of inspired oxygen (FiO 2 )-adjustable device. Mean FiO 2 on noninvasive support was 0.56 and on invasive support was 0.37. Mean partial pressure of oxygen (PaO 2 ) on oxygen therapy was 108.7 torr and 3,037 (42.1%) of PaO 2 measurements were >100 torr. Despite relatively low FiO 2 , PICU patients receiving oxygen therapy are commonly exposed to prolonged hyperoxemia, which may contribute to ongoing organ injury.

Pre-oxygenation with high-flow oxygen through the nasopharyngeal airway compared to facemask on carbon dioxide clearance in emergency adults: a prospective randomized non-blinded clinical trial

INTRODUCTION

Before tracheal intubation, it is essential to provide sufficient oxygen reserve for emergency patients with full stomachs. Recent studies have demonstrated that high-flow nasal oxygen (HFNO) effectively pre-oxygenates and prolongs apneic oxygenation during tracheal intubation. Despite its effectiveness, the use of HFNO remains controversial due to concerns regarding carbon dioxide clearance. The air leakage and unknown upper airway obstruction during HFNO therapy cause reduced oxygen flow above the vocal cords, possibly weaken the carbon dioxide clearance.

METHODS

Patients requiring emergency surgery who had fasted < 8 h and not drunk < 2 h were randomly assigned to the high-flow group, who received 100% oxygen at 30-60 L/min through nasopharyngeal airway (NPA), or the mask group, who received 100% oxygen at 8 L/min. PaO2 and PaCO2 were measured immediately before pre-oxygenation (T0), anesthesia induction (T1), tracheal intubation (T2), and mechanical ventilation (T3). The gastric antrum's cross-sectional area (CSA) was measured using ultrasound technology at T0, T1, and T3. Details of complications, including hypoxemia, reflux, nasopharyngeal bleeding, postoperative pulmonary infection, postoperative nausea and vomiting (PONV), and postoperative nasopharyngeal pain, were recorded. The primary outcomes were PaCO2 measured at T1, T2, and T3. The secondary outcomes included PaO2 at T1, T2, and T3, CSA at T1 and T3, and complications happened during this trial.

RESULTS

Pre-oxygenation was administered by high-flow oxygen through NPA (n = 58) or facemask (n = 57) to 115 patients. The mean (SD) PaCO2 was 32.3 (6.7) mmHg in the high-flow group and 34.6 (5.2) mmHg in the mask group (P = 0.045) at T1, 45.0 (5.5) mmHg and 49.4 (4.6) mmHg (P < 0.001) at T2, and 47.9 (5.1) mmHg and 52.9 (4.6) mmHg (P < 0.001) at T3, respectively. The median ([IQR] [range]) PaO2 in the high-flow and mask groups was 404.5 (329.1-458.1 [159.8-552.9]) mmHg and 358.9 (274.0-413.3 [129.0-539.1]) mmHg (P = 0.007) at T1, 343.0 (251.6-428.7 [73.9-522.1]) mmHg and 258.3 (162.5-347.5 [56.0-481.0]) mmHg (P < 0.001) at T2, and 333.5 (229.9-411.4 [60.5-492.4]) mmHg and 149.8 (87.0-246.6 [51.2-447.5]) mmHg (P < 0.001) at T3, respectively. The CSA in the high-flow and mask groups was 371.9 (287.4-557.9 [129.0-991.2]) mm2 and 386.8 (292.0-537.3 [88.3-1651.7]) mm2 at T1 (P = 0.920) and 452.6 (343.7-618.4 [161.6-988.1]) mm2 and 385.6 (306.3-562.0 [105.5-922.9]) mm2 at T3 (P = 0.173), respectively. The number (proportion) of complications in the high-flow and mask groups is shown below: hypoxemia: 1 (1.7%) vs. 9 (15.8%, P = 0.019); reflux: 0 (0%) vs. 0 (0%); nasopharyngeal bleeding: 1 (1.7%) vs. 0 (0%, P = 1.000); pulmonary infection: 4 (6.9%) vs. 3 (5.3%, P = 1.000); PONV: 4 (6.9%) vs. 4 (7.0%, P = 1.000), and nasopharyngeal pain: 0 (0%) vs. 0 (0%).

CONCLUSIONS

Compared to facemasks, pre-oxygenation with high-flow oxygen through NPA offers improved carbon dioxide clearance and enhanced oxygenation prior to tracheal intubation in patients undergoing emergency surgery, while the risk of gastric inflation had not been ruled out.

TRIAL REGISTRATION

This trial was registered prospectively at the Chinese Clinical Research Registry on 26/4/2022 (Registration number: ChiCTR2200059192).

Effects of a lower versus a higher oxygenation target in intensive care unit patients with chronic obstructive pulmonary disease and acute hypoxaemic respiratory failure: a subgroup analysis of a randomised clinical trial

Background

Oxygen supplementation is ubiquitous in intensive care unit (ICU) patients with chronic obstructive pulmonary disease (COPD) and acute hypoxaemia, but the optimal oxygenation target has not been established.

Methods

This was a pre-planned subgroup analysis of the Handling Oxygenation Targets in the ICU (HOT-ICU) trial, which allocated patients with acute hypoxaemia to a lower oxygenation target (partial pressure of arterial oxygen [Pao2] of 8 kPa) vs a higher target (Pao2 of 12 kPa) during ICU admission, for up to 90 days; the allocation was stratified for presence or absence of COPD. Here, we report key outcomes for patients with COPD.

Results

The HOT-ICU trial enrolled 2928 patients of whom 563 had COPD; 277 were allocated to the lower and 286 to the higher oxygenation group. After allocation, the median Pao2 was 9.1 kPa (inter-quartile range 8.7-9.9) in the lower group vs 12.1 kPa (11.2-12.9) in the higher group. Data for arterial carbon dioxide (Paco2) were available for 497 patients (88%) with no between-group difference in time-weighted average; median Paco2 6.0 kPa (5.2-7.2) in the lower group vs 6.2 kPa (5.4-7.3) in the higher group. At 90 days, 122/277 patients (44%) in the lower oxygenation group had died vs 132/285 patients (46%) in the higher (relative risk 0.98; 95% confidence interval 0.82-1.17; P=0.67). No statistically significant differences were found in any secondary outcome.

Conclusions

In ICU patients with COPD and acute hypoxaemia, a lower vs a higher oxygenation target did not reduce mortality. There were no between-group differences in Paco2 or in secondary outcomes.

Clinical trial registration

NCT03174002, EudraCT number 2017-000632-34.

Applying Noninvasive Ventilation in Treatment of Acute Exacerbation of COPD Using Evidence-Based Interprofessional Clinical Practice

When administered as first-line intervention to patients admitted with acute hypercapnic respiratory failure secondary to COPD exacerbation in conjunction with guideline-recommended therapies, noninvasive ventilation (NIV) has been shown to reduce mortality and endotracheal intubation. Opportunities to increase uptake of NIV continue to exist despite inclusion of this therapy in clinical guidelines. Identifying patients appropriate for NIV, and subsequently providing close monitoring to determine an improvement in clinical condition involves a team consisting of physician, nurse, and respiratory therapist in institutions that successfully implement NIV. We describe to our knowledge the first known evidence-based algorithm speaking to initiation, titration, monitoring, and weaning of NIV in treatment of acute exacerbation of COPD that incorporates the necessary interprofessional collaboration among physicians, nurses, and respiratory therapists caring for these patients.

Effect of automated titration of oxygen on time spent in a prescribed oxygen saturation range in adults in the ICU after cardiac surgery

Objective

The objective of this study was to determine whether automated titration of the fraction of inspired oxygen (FiO2) increases the time spent with oxygen saturation (SpO2) within a predetermined target SpO2 range compared with manually adjusted high-flow oxygen therapy in postoperative cardiac surgical patients managed in the intensive care unit (ICU).

Design

Single-centre, open-label, randomised clinical trial.

Setting

Tertiary centre ICU.

Participants

Recently extubated adults following elective cardiac surgery who required supplemental oxygen.

Interventions

Automatically adjusted FiO2 (using an automated oxygen control system) compared with manual FiO2 titration, until cessation of oxygen therapy, ICU discharge, or 24 h (whichever was sooner).

Main outcome measures

The primary outcome was the proportion of time receiving oxygen therapy with the SpO2 in a SpO2 target range of 92-96 %.

Results

Among 65 participants, the percentage of time per patient spent in the target SpO2 range was a median of 97.7 % (interquartile range: 87.9-99.2 %) and 91.3 % (interquartile range: 77.1-96.1 %) in the automated (n = 28) and manual (n = 28) titration groups, respectively. The estimated effect of automated FiO2, compared to manual FiO2 titration, was to increase the percentage of time spent in the target range by a median of 4.8 percentage points (95 % confidence interval: 1.6 to 10.3 percentage points, p = 0.01).

Conclusion

In patients recently extubated after cardiac surgery, automated FiO2 titration significantly increased time spent in a target SpO2 range of 92-96 % compared to manual FiO2 titration.

Implementing High-Flow Nasal Oxygen Therapy in Medical Wards: A Scoping Review to Understand Hospital Protocols and Procedures

Acute hypoxemic respiratory failure (ARF) is a common cause for hospital admission. High-flow nasal oxygen (HFNO) is increasingly used as a first-line treatment for patients with ARF, including in medical wards. Clinical guidance is crucial when providing HFNO, and health services use local health guidance documents (LHGDs) to achieve this. It is unknown what hospital LHGDs recommend regarding ward administration of HFNO. This study examined Australian hospitals' LHGDs regarding ward-based HFNO administration to determine content that may affect safe delivery. A scoping review was undertaken on 2 May 2022 and updated on 29 January 2024 to identify public hospitals' LHGDs regarding delivery of HFNO to adults with ARF in medical wards in two Australian states. Data were extracted and analysed regarding HFNO initiation, monitoring, maintenance and weaning, and management of clinical deterioration. Of the twenty-six included LHGDs, five documents referenced Australian Oxygen Guidelines. Twenty LHGDs did not define a threshold level of hypoxaemia where HFNO use was recommended over conventional oxygen therapy. Thirteen did not provide target oxygen saturation ranges whilst utilising HFNO. Recommendations varied regarding maximal levels of inspired oxygen and flow rates in the medical ward. Eight LHGDs did not specify any system to identify and manage deteriorating patients. Five LHGDs did not provide guidance for weaning patients from HFNO. There was substantial variation in the LHGDs regarding HFNO care for adult patients with ARF in Australian hospitals. These findings have implications for the delivery of high-quality, safe clinical care in hospitals.

New perspective crosslinking electrochemistry and other research fields: beyond electrochemical reactors

Over the years, electrochemical reactors have evolved significantly, with modern reactors now able to achieve a high current density and power output in compact sizes. This leap in performance has not only greatly accelerated the rate of electrochemical reactions but also had a broader impact on the environment. Traditional research perspectives, focused primarily on the internal working systems of reactors, possibly overlook the potential of electrochemical systems in regulating their surrounding environment. A novel research perspective considering the interaction between electrochemical processes and their environmental context as a unified subject of study has gradually emerged alongside the dramatic development of electrochemical techniques. This viewpoint introduces a paradigm shift: electrochemical reactors are not isolated entities but rather are integral parts that interact with their surroundings. Correspondingly, this calls for an innovative research methodology that goes beyond studying the electrochemical processes in isolation. Rather, it integrates the design of the electrochemical system with its specific application environment, ensuring seamless integration for optimal performance under various practical conditions. Therefore, performance metrics should include not only the basic parameters of the electrochemical reactions but also the adaptability of the electrochemical system in real-world scenarios beyond the laboratory. By focusing on environmental integration and application-driven design, the applications of electrochemical technology can be more effectively leveraged. This perspective is exemplified by an electrochemical system based on coupled cathodic oxygen reduction and anodic oxygen evolution reactions. By adopting this new research paradigm, the applications of this electrochemical system can be extended to fields like medical treatment, food science, and microbial fermentation, with an emphasis on tailored designs for these specific application fields. This comprehensive and systematic new research approach aims to fully explore the potential applications of electrochemical technology and foster interdisciplinary collaboration in the electrochemical field.

Factors associated with intubation in patients with acute hypoxaemic respiratory failure treated with high-flow nasal cannula oxygen therapy: A prospective, observational study

BACKGROUND

High-flow nasal cannula (HFNC) oxygen is an alternative to conventional oxygen in acute hypoxaemic respiratory failure. Some patients require intubation, with a risk of delay; thus, early predictors may identify those requiring earlier intubation. The "ROX" index (ratio of pulse oximetry/fraction of inspired oxygen to respiratory rate) predicts intubation in patients with pneumonia treated with HFNC therapy, but this index has not been validated in non-pneumonia causes of acute hypoxaemic respiratory failure.

AIM/OBJECTIVE

The aim of this study was to identify factors associated with intubation in a heterogeneous group of patients with acute hypoxaemic respiratory failure treated with HFNC oxygen.

METHODS

This prospective observational study was undertaken in an Australian tertiary intensive care unit and included patients over 18 y of age with acute hypoxaemic respiratory failure who were treated with oxygen via HFNC. Vital signs and arterial blood gases were recorded prospectively at baseline and regular prespecified intervals for 48 h after HFNC initiation. Multivariate logistic regression was used to identify the factors associated with intubation.

RESULTS

Forty-three patients were included (N = 43). The multivariate factors associated with intubation were admission Sequential Organ Failure Assessment score (odds ratio [OR]: 1.94 [95% confidence interval {CI}: 1.06-3.57]; p = 0.032) and Pneumonia Severity Index (OR: 0.95 [95% CI: 0.90-0.99]; p = 0.034). The ROX index was not independently associated with intubation when adjusted for Sequential Organ Failure Assessment score (OR: 0.71 [95% CI: 0.47-1.06]; p = 0.09). There was no difference in mortality between patients intubated early (<24 h) compared to those intubated late.

CONCLUSIONS

Intubation was associated with admission Sequential Organ Failure Assessment score and Pneumonia Severity Index. The ROX index was not associated with intubation when adjusted for admission Sequential Organ Failure Assessment score. Outcomes were similar irrespective of whether patients were intubated late rather than early.

Assessing the safety of physical rehabilitation in critically ill patients: a Delphi study

BACKGROUND

Physical rehabilitation of critically ill patients is implemented to improve physical outcomes from an intensive care stay. However, before rehabilitation is implemented, a risk assessment is essential, based on robust safety data. To develop this information, a uniform definition of relevant adverse events is required. The assessment of cardiovascular stability is particularly relevant before physical activity as there is uncertainty over when it is safe to start rehabilitation with patients receiving vasoactive drugs.

METHODS

A three-stage Delphi study was carried out to (a) define adverse events for a general ICU cohort, and (b) to define which risks should be assessed before physical rehabilitation of patients receiving vasoactive drugs. An international group of intensive care clinicians and clinician researchers took part. Former ICU patients and their family members/carers were involved in generating consensus for the definition of adverse events. Round one was an open round where participants gave their suggestions of what to include. In round two, participants rated their agreements with these suggestions using a five-point Likert scale; a 70% consensus agreement threshold was used. Round three was used to re-rate suggestions that had not reached consensus, whilst viewing anonymous feedback of participant ratings from round two.

RESULTS

Twenty-four multi-professional ICU clinicians and clinician researchers from 10 countries across five continents were recruited. Average duration of ICU experience was 18 years (standard deviation 8) and 61% had publications related to ICU rehabilitation. For the adverse event definition, five former ICU patients and one patient relative were recruited. The Delphi process had a 97% response rate. Firstly, 54 adverse events reached consensus; an adverse event tool was created and informed by these events. Secondly, 50 risk factors requiring assessment before physical rehabilitation of patients receiving vasoactive drugs reached consensus. A second tool was created, informed by these suggestions.

CONCLUSIONS

The adverse event tool can be used in studies of physical rehabilitation to ensure uniform measurement of safety. The risk assessment tool can be used to inform clinical practise when risk assessing when to start rehabilitation with patients receiving vasoactive drugs. Trial registration This study protocol was retrospectively registered on https://www.researchregistry.com/ (researchregistry2991).

Effect of postoperative oxygen therapy regimen modification on oxygenation in patients with acute type A aortic dissection

Objective

In this study, we investigated the effect of various oxygen therapy regimens on oxygenation in patients with acute type A aortic dissection (AAD).

Methods

A quasi-randomized controlled trial was conducted, in which patients with AAD hospitalized for surgery from June to September 2021 were assigned to the control group (patients received conventional oxygen therapy after postoperative mechanical ventilation, weaning, and extubation) and those who were admitted from October to December 2021 were assigned to the observation group [patients underwent optimally adjusted therapy based on the treatment of the control group, which mainly included prioritized elevation of positive end-expiratory pressure (PEEP) and restricted use of the fraction of inspired oxygen (FiO2)].The postoperative oxygenation index, blood gas analysis, and duration of mechanical ventilation were compared between the two groups.

Results

There were significant differences in oxygenation observed at 2 h postoperatively between the groups. 12, 24, and 72 h postoperatively, the oxygenation index varied significantly between the two groups. There were statistically significant differences in the time effects of the oxygenation index and PaO2 between the two groups, as well as significant differences in the length of stay in the intensive care unit.

Conclusion

For the postoperative care of patients with AAD, it is suggested that the minimum FiO2 required for oxygenation of patients be maintained. In addition, it is possible to enhance PEEP as a priority when PaO2 is low.

Conservative versus liberal oxygen therapy for intensive care unit patients: meta-analysis of randomized controlled trials

BACKGROUND

It remains unclear whether conservative oxygen therapy (COT) or liberal oxygen therapy (LOT) is more beneficial to the clinical outcomes of intensive care unit (ICU) patients. We systematically reviewed the efficacy and safety of conservative versus liberal oxygen therapy for ICU patients.

METHODS

We systematically searched PubMed, Embase, Web of Science, Scopus, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, MedRxiv, and BioRxiv for reports on randomized controlled trials (RCTs) that compared the effects of COT versus LOT on the clinical outcomes of ICU patients published in English before April 2024. The primary outcome was the mortality rate, secondary outcomes included ICU and hospital length of stay, days free from mechanical ventilation support (MVF), vasopressor-free time (VFT), and adverse events.

RESULTS

In all, 13 RCTs involving 10,632 patients were included in analyses. Meta-analysis showed COT did not reduce mortality at 30-day (risk ratio [RR] = 1.01, 95% confidence interval [CI] 0.94 to 1.09, I2 = 42%, P = 0.78), 90-day (RR = 1.01, 95% CI 0.95 to 1.08, I2 = 9%, P = 0.69), or longest follow-up (RR = 1.00, 95% CI 0.95 to 1.06, I2 = 22%, P = 0.95) compared to LOT in ICU patients. In subgroup analyses, no significant difference was observed between the two groups in terms of the different ICU, baseline P/F, and actual PaO2. In addition, COT did not affect ICU length of stay, hospital length of stay, or VFT, it only affected MVF days.

CONCLUSIONS

COT did not reduce all-cause mortality in ICU patients. Further RCTs are urgently needed to confirm the impact of COT strategy on specific populations.

Non-tuberculous mycobacterial pulmonary infection presenting in a patient with unilateral pulmonary artery agenesis

People who have structural or developmental lung disease are more likely to develop non-tuberculous mycobacterial infections. We present the case of a young man in his 30s who had unilateral pulmonary artery agenesis on the right side and presented with a 6-month history of productive cough and fever. His CT scan showed nodular and cavitating lesions on the right side, and sputum analysis confirmed infection with Mycobacterium chimaera He had to undergo modifications in his treatment, including a change from rifampicin to rifabutin due to drug interactions and his amikacin had to be stopped due to signs of vestibular toxicity. Using a multidisciplinary approach, we were able to formulate an appropriate drug regimen for him, and he is now under regular follow-up with infectious diseases and respiratory medicine.

Assessment of hypoxemia among young adults with sickle cell anaemia in steady state in southwestern Nigeria: a crosssectional study

OBJECTIVES

Hypoxia is a known feature of sickle cell anaemia (SCA) which results from chronic anaemia and recurrent vaso-occlusive crisis (VOC) which can cause tissue ischaemia that leads to an end organ damage. The hallmark of SCA is chronic anaemia and recurrent vaso-occlusive crisis. The aim of this study is to compare the oxygen saturation of sickle cell anaemic individuals with the normal haemoglobin type (Hb AA) control and also to determine the prevalence of hypoxemia among SCA.

RESULTS

Two-hundred and twenty-two (136 Hb SS and 86 Hb AA) participated in the study. The mean ± SD of age (years), oxygen saturation (%) and pulse rate (bpm) of participants with sickle cell anaemia and Hb AA control were 21.85 ± 3.04 and 22.14 ± 3.18 (t = 0.701, p = 0.436), 95.21 ± 3.02 and 98.07 ± 0.81 (t=-8.598, p < 0.0001) and 77.10 ± 9.28 and 73.16 ± 8.52 (t = 3.173, p = 0.002) respectively. The prevalence of hypoxemia among SCA participants was 47.1%. Prevalence of hypoxemia in males with SCA was 60.9% while 39.1% of the females had hypoxemia.

Oxygenation During Venoarterial Extracorporeal Membrane Oxygenation: Physiology, Current Evidence, and a Pragmatic Approach to Oxygen Titration

OBJECTIVES

This review aims to: 1) identify the key circuit and patient factors affecting systemic oxygenation, 2) summarize the literature reporting the association between hyperoxia and patient outcomes, and 3) provide a pragmatic approach to oxygen titration, in patients undergoing peripheral venoarterial extracorporeal membrane oxygenation (ECMO).

DATA SOURCES

Searches were performed using PubMed, SCOPUS, Medline, and Google Scholar.

STUDY SELECTION

All observational and interventional studies investigating the association between hyperoxia, and clinical outcomes were included, as well as guidelines from the Extracorporeal Life Support Organization.

DATA EXTRACTION

Data from relevant literature was extracted, summarized, and integrated into a concise narrative review. For ease of reference a summary of relevant studies was also produced.

DATA SYNTHESIS

The extracorporeal circuit and the native cardiorespiratory circuit both contribute to systemic oxygenation during venoarterial ECMO. The ECMO circuit's contribution to systemic oxygenation is, in practice, largely determined by the ECMO blood flow, whereas the native component of systemic oxygenation derives from native cardiac output and residual respiratory function. Interactions between ECMO outflow and native cardiac output (as in differential hypoxia), the presence of respiratory support, and physiologic parameters affecting blood oxygen carriage also modulate overall oxygen exposure during venoarterial ECMO. Physiologically those requiring venoarterial ECMO are prone to hyperoxia. Hyperoxia has a variety of definitions, most commonly Pa o2 greater than 150 mm Hg. Severe hypoxia (Pa o2 > 300 mm Hg) is common, seen in 20%. Early severe hyperoxia, as well as cumulative hyperoxia exposure was associated with in-hospital mortality, even after adjustment for disease severity in both venoarterial ECMO and extracorporeal cardiopulmonary resuscitation. A pragmatic approach to oxygenation during peripheral venoarterial ECMO involves targeting a right radial oxygen saturation target of 94-98%, and in selected patients, titration of the fraction of oxygen in the mixture via the air-oxygen blender to target postoxygenator Pa o2 of 150-300 mm Hg.

CONCLUSIONS

Hyperoxia results from a range of ECMO circuit and patient-related factors. It is common during peripheral venoarterial ECMO, and its presence is associated with poor outcome. A pragmatic approach that avoids hyperoxia, while also preventing hypoxia has been described for patients receiving peripheral venoarterial ECMO.

Acute Pancreatitis during and after Pregnancy: A Review

During pregnancy and in the post-partum period, several diseases may arise or become exacerbated. Acute pancreatitis is an inflammatory disease with an increasing incidence in Western countries. The incidence of acute pancreatitis during pregnancy is not different with respect to the general population, but this incidence increases in the first 2 years after delivery. Biliary sludge and stones are the most frequent aetiologies, followed by hypertriglyceridemia. Taking care of the mother and foetus through a potentially severe disease requires a team consisting of an obstetrician, a gastroenterologist, an anaesthesiologist, and a surgeon. It is necessary to monitor the health of the foetus/child and the mother during pregnancy, childbirth, and puerperium. The management of this care depends on the systemic and local complications, the severity of the acute pancreatitis, and the trimester of pregnancy. Some diagnostic tools and many drugs are not safe for foetuses, while interventional endoscopy and surgery have limitations and can only be used after an accurate evaluation of benefit/risk ratios. Despite these limitations, maternal mortality due to acute pancreatitis is low during pregnancy, mainly thanks to multidisciplinary approaches for these patients. A careful diet to prevent obesity, alcohol abstinence, routine serum triglyceride control, and breastfeeding for at least three months may prevent acute pancreatitis during and after pregnancy.

Acid base and metabolic parameters of the umbilical cord blood and cerebral oxygenation immediately after birth

Objective

Aim was to investigate whether acid-base and metabolic parameters obtained from arterial umbilical cord blood affect cerebral oxygenation after birth in preterm neonates with respiratory support and in term neonates without respiratory support.

Study design

This was a post-hoc analysis of secondary outcome parameters of a prospective observational study including preterm neonates with and term neonates without respiratory support. Non-asphyxiated neonates with cerebral oxygenation measured with near-infrared spectroscopy during the first 15 min and with blood gas analyses from arterial umbilical cord blood were included. Arterial oxygen saturation (SpO2) and heart rate (HR) were monitored with pulse oximetry. Potential correlations were investigated between acid-base and metabolic parameters (pH-value, bicarbonate, base-excess, and lactate) and crSO2/cFTOE 5 min after birth.

Results

Seventy-seven neonates were included: 14 preterm neonates with respiratory support (mean gestational age [GA] 31.4 ± 4.1 weeks; mean birth weight [BW] 1,690 ± 640 g) and 63 term neonates without respiratory support (GA 38.7 ± 0.8 weeks; BW 3,258 ± 443 g). Mean crSO2 5 min after birth was 44.0% ± 24.2% in preterm and 62.2% ± 20.01% in term neonates. Mean cFTOE 5 min after birth was 0.46 ± 0.06 in preterm and 0.27 ± 0.19 in term neonates. In preterm neonates with respiratory support higher lactate was significantly associated with lower crSO2 and SpO2 and tended to be associated with higher cFTOE. In term neonates without respiratory support no significant correlations were found.

Conclusion

In non-asphyxiated preterm neonates with respiratory support, lactate levels were negatively associated with crSO2 and SpO2, whereas in term neonates without respiratory support no associations were observed.

Diagnosis of cystic lung diseases: a position statement from the UK Cystic Lung Disease Rare Disease Collaborative Network

BACKGROUND

Rare cystic lung diseases are increasingly recognised due the wider application of CT scanning making cystic lung disease management a growing part of respiratory care. Cystic lung diseases tend to have extrapulmonary features that can both be diagnostic but also require surveillance and treatment in their own right. As some of these diseases now have specific treatments, making a precise diagnosis is crucial. While Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia and lymphangioleiomyomatosis are becoming relatively well-known diseases to respiratory physicians, a targeted and thorough workup improves diagnostic accuracy and may suggest other ultrarare diseases such as light chain deposition disease, cystic pulmonary amyloidosis, low-grade metastatic neoplasms or infections. In many cases, diagnostic information is overlooked leaving uncertainty over the disease course and treatments.

AIMS

This position statement from the Rare Disease Collaborative Network for cystic lung diseases will review how clinical, radiological and physiological features can be used to differentiate between these diseases.

NARRATIVE

We highlight that in many cases a multidisciplinary diagnosis can be made without the need for lung biopsy and discuss where tissue sampling is necessary when non-invasive methods leave diagnostic doubt. We suggest an initial workup focusing on points in the history which identify key disease features, underlying systemic and familial diseases and a clinical examination to search for connective tissue disease and features of genetic causes of lung cysts. All patients should have a CT of the thorax and abdomen to characterise the pattern and burden of lung cysts and extrapulmonary features and also spirometry, gas transfer and a 6 min walk test. Discussion with a rare cystic lung disease centre is suggested before a surgical biopsy is undertaken.

CONCLUSIONS

We suggest that this focused workup should be performed in all people with multiple lung cysts and would streamline referral pathways, help guide early treatment, management decisions, improve patient experience and reduce overall care costs. It could also potentially catalyse a national research database to describe these less well-understood and unidentified diseases, categorise disease phenotypes and outcomes, potentially leading to better prognostic data and generating a stronger platform to understand specific disease biology.

Disseminated Mycobacterium abscessus with endocarditis

We present an uncommon case of endocarditis caused by Mycobacterium abscessus in an immunocompetent patient following a caesarean section. We discuss her turbulent admission course leading to her diagnosis following persistent M. abscessus bacteraemia, medical and surgical management, including a splenectomy and valve resection and repair, and subsequent prolonged course of combination antimicrobials for 24 months post valve surgery. The patient is alive 9 months after completing her treatment and 36 months after her valve surgery. We emphasise the importance of a multidisciplinary team approach in the management of such a complex case.