Effect of a lower target oxygen saturation range on the risk of hypoxaemia and elevated NEWS2 scores at a university hospital: a retrospective study.

BACKGROUND: The optimal target oxygen saturation (SpO2) range for hospital inpatients not at risk of hypercapnia is unknown. The objective of this study was to assess the impact on oxygen usage and National Early Warning Score 2 (NEWS2) of changing the standard SpO2 target range from 94-98% to 92-96%. METHODS: In a metropolitan UK hospital, a database of electronic bedside SpO2 measurements, oxygen prescriptions and NEWS2 records was reviewed. Logistic regression was used to compare the proportion of hypoxaemic SpO2 values (<90%) and NEWS2 records ≥5 in 2019, when the target SpO2 range was 94-98%; with 2022, when the target range was 92-96%. RESULTS: In 2019, 218 of 224 936 (0.10%) observations on room air and 162 of 11 328 (1.43%) on oxygen recorded an SpO2 <90%, and in 2022, 251 of 225 970 (0.11%) and 233 of 12 845 (1.81%), respectively (risk difference 0.04%, 95% CI 0.02% to 0.07%). NEWS2 ≥5 was observed in 3009 of 236 264 (1.27%) observations in 2019 and 4061 of 238 815 (1.70%) in 2022 (risk difference 0.43%, 0.36% to 0.50%; p<0.001). The proportion of patients using supplemental oxygen with hyperoxaemia (SpO2 100%) was 5.4% in 2019 and 3.9% in 2022 (OR 0.71, 0.63 to 0.81; p<0.001). DISCUSSION: The proportion of observations with SpO2 <90% or NEWS2 ≥5 was greater with the 92-96% range; however, absolute differences were very small and of doubtful clinical relevance, in contrast to hyperoxaemia for which the proportion was markedly less in 2022. These findings support proposals that the British Thoracic Society oxygen guidelines could recommend a lower target SpO2 range.

Evaluating the clinical and cost-effectiveness of a conservative approach to oxygen therapy for invasively ventilated adults in intensive care: Protocol for the UK-ROX trial.

Background: In the United Kingdom, around 184,000 adults are admitted to an intensive care unit (ICU) each year with over 30% receiving mechanical ventilation. Oxygen is the commonest therapeutic intervention provided to these patients but it is unclear how much oxygen should be administered for the best clinical outcomes. Methods: The UK-ROX trial will evaluate the clinical and cost-effectiveness of conservative oxygen therapy (the minimum oxygen concentration required to maintain an oxygen saturation of 90% ± 2%) versus usual oxygen therapy in critically ill adults receiving supplemental oxygen when invasively mechanically ventilated in ICUs in England, Wales and Northern Ireland. The trial will recruit 16,500 patients from approximately 100 UK adult ICUs. Using a deferred consent model, enrolled participants will be randomly allocated (1:1) to conservative or usual oxygen therapy until ICU discharge or 90 days after randomisation. Objectives: The primary clinical outcome is all cause mortality at 90 days following randomisation. Discussion: The UK-ROX trial has received ethical approval from the South Central - Oxford C Research Ethics Committee (Reference: 20/SC/0423) and the Confidentiality Advisory Group (Reference: 22/CAG/0154). The trial commenced in May 2021 and, at the time of publication, 95 sites had opened to recruitment.

A crossover study of short burst oxygen therapy (SBOT) for the relief of exercise-induced breathlessness in severe COPD.

BACKGROUND: Previous small studies suggested SBOT may be ineffective in relieving breathlessness after exercise in COPD. METHODS: 34 COPD patients with FEV1 <40% predicted and resting oxygen saturation ≥93% undertook an exercise step test 4 times. After exercise, patients were given 4 l/min of oxygen from a simple face mask, 4 l/min air from a face mask (single blind), air from a fan or no intervention. RESULTS: Average oxygen saturation fell from 95.0% to 91.3% after exercise. The mean time to subjective recovery was 3.3 minutes with no difference between treatments. The mean Borg breathlessness score was 1.5/10 at rest, rising to 5.1/10 at the end of exercise (No breathlessness = 0, worst possible breathlessness = 10). Oxygen therapy had no discernable effect on Borg scores even for 14 patients who desaturated below 90%. 15 patients had no preferred treatment, 7 preferred oxygen, 6 preferred the fan, 3 preferred air via a mask and 3 preferred room air. CONCLUSIONS: This study provides no support for the idea that COPD patients who are not hypoxaemic at rest derive noticeable benefit from oxygen therapy after exercise. Use of air from a mask or from a fan had no apparent physiological or placebo effect.

Randomized controlled trial of oral antifungal treatment for severe asthma with fungal sensitization: The Fungal Asthma Sensitization Trial (FAST) study.

RATIONALE: Some patients with severe asthma are immunologically sensitized to one or more fungi, a clinical entity categorized as severe asthma with fungal sensitization (SAFS). It is not known whether SAFS responds to antifungal therapy. OBJECTIVES: To evaluate the response of SAFS to oral itraconazole. METHODS: Patients with severe asthma sensitized to at least one of seven fungi by skin prick or specific IgE testing were recruited. All had total IgE less than 1,000 IU/ml and negative Aspergillus precipitins. They were treated with oral itraconazole (200 mg twice daily) or placebo for 32 weeks, with follow-up for 16 weeks. MEASUREMENTS AND MAIN RESULTS: The primary end point was change in the Asthma Quality of Life Questionnaire (AQLQ) score, with rhinitis score, total IgE, and respiratory function as secondary end points. Fifty-eight patients were enrolled, of whom 41% had been hospitalized in the previous year. Baseline mean AQLQ score was 4.13 (range, 1-7). At 32 weeks, the improvement (95% confidence interval) in AQLQ score was +0.85 (0.28, 1.41) in the antifungal group, compared with a -0.01 (-0.43, 0.42) change in the placebo group (P = 0.014). Rhinitis score improved (-0.43) in the antifungal, and deteriorated (+0.17) in the placebo group (P = 0.013). Morning peak flow improved (20.8 L/minute, P = 0.028) in the antifungal group. Total serum IgE decreased in the antifungal group (-51 IU/ml) but increased in placebo group (+30 IU/ml) (P = 0.001). No severe adverse events were observed, but seven patients developed adverse events requiring discontinuation, five in the antifungal group. CONCLUSIONS: SAFS responds to oral antifungal therapy as judged by large improvements in quality of life in about 60% of patients.

Survey of major complications of intercostal chest drain insertion in the UK.

BACKGROUND: Following reports from the National Patient Safety Agency of deaths and serious harm from intercostal chest drains (ICD) we conducted a national survey among chest physicians of their experience of harm associated with ICD. METHODS: A questionnaire was sent to 198 UK chest physicians at 148 acute hospital trusts, enquiring about current practice and any adverse incidents related to chest drains from 2003 to 2008. RESULTS: 101 of 148 trusts (68%) replied. 67 trusts reported at least one major incident involving ICD insertion. 31 Cases of ICD misplacement were reported with seven deaths. Misplaced drains were inserted in liver (10), peritoneal space (6), heart (5), spleen (5), subclavian vessels (2), colon (1), oesophagus (1) and inferior vena cava (1). 47 cases of serious lung or chest wall injuries with eight deaths and six cases of ICD placement on the wrong side with two deaths were reported. The guidewire was lost in the pleural cavity in three cases. 22 of 101 trusts required written patient consent before ICD insertion. 11 trusts had a training policy. 16 trusts had patient information literature for this procedure. The seniority of doctors permitted to insert ICDs was as follows: 30% any doctor; 27% at least 1 year post qualification; 32% at least 2 years, 11% at least 4 years. CONCLUSIONS: 67% of responding trusts had encountered major complications of ICD. The survey raised concerns about training and consent. The National Patient Safety Agency has made recommendations to address these risks which are also addressed in the 2009 update of the British Thoracic Society Pleural Disease Guideline.

Oxygen Use in Critical Illness.

Oxygen is the most commonly used drug in critical care. However, because it is a gas, most clinicians and most patients do not regard it as a drug. For this reason, the use of medical oxygen over the past century has been driven by custom, practice, and "precautionary principles" rather than by scientific principles. Oxygen is a life-saving drug for patients with severe hypoxemia, but, as with all other drugs, too much can be harmful. It has been known for many decades that the administration of supplemental oxygen is hazardous for some patients with COPD and other patients who are vulnerable to retention of carbon dioxide (ie, hypercapnia). It has been recognized more recently that excessive oxygen therapy is associated with significantly increased mortality in critically ill patients, even in the absence of risk factors for hypercapnia. This paper provides a critical overview of past and present oxygen use for critically ill patients and will provide guidance for safer oxygen use in the future.

Protocol for a feasibility randomised controlled trial of targeted oxygen therapy in mechanically ventilated critically ill patients.

INTRODUCTION: Oxygen is the most commonly administered drug to mechanically ventilated critically ill adults, yet little is known about the optimum oxygen saturation (SpO2) target for these patients; the current standard of care is an SpO2 of 96% or above. Small pilot studies have demonstrated that permissive hypoxaemia (aiming for a lower SpO2 than normal by using a lower fractional inspired oxygen concentration (FIO2)) can be achieved in the critically ill and appears to be safe. This approach has not been evaluated in a National Health Service setting. It is possible that permissive hypoxaemia may be beneficial to critically ill patients thus it requires robust evaluation. METHODS AND ANALYSIS: Targeted OXygen therapY in Critical illness (TOXYC) is a feasibility randomised controlled trial (RCT) to evaluate whether recruiting patients to a study of permissive hypoxaemia is possible in the UK. It will also investigate biological mechanisms that may underlie the links between oxygenation and patient outcomes. Mechanically ventilated patients with respiratory failure will be recruited from critical care units at two sites and randomised (1:1 ratio) to an SpO2 target of either 88%-92% or ≥96% while intubated with an endotracheal tube. Clinical teams can adjust FIO2 and ventilator settings as they wish to achieve these targets. Clinical information will be collected before, during and after the intervention and blood samples taken to measure markers of systemic oxidative stress. The primary outcome of this study is feasibility, which will be assessed by recruitment rate, protocol adherence and withdrawal rates. Secondary outcomes will include a comparison of standard critical care outcome measures between the two intervention groups, and the measurement of biomarkers of systemic oxidative stress. The results will be used to calculate a sample size, likely number of sites and overall length of time required for a subsequent large multicentre RCT. ETHICS AND DISSEMINATION: This study was approved by the London - Harrow Research Ethics Committee on 2 November 2017 (REC Reference 17/LO/1334) and received HRA approval on 13 November 2017. Results from this study will be disseminated in peer-reviewed journals, at medical and scientific meetings, in the NIHR Journals Library and patient information websites. TRIAL REGISTRATION NUMBER: NCT03287466; Pre-results.

Anthracofibrosis, bronchial stenosis with overlying anthracotic mucosa: possibly a new occupational lung disorder: a series of seven cases From one UK hospital.

Anthracofibrosis, which was recently defined as bronchial stenosis with overlying anthracotic mucosa, has been infrequently reported in Asia as a complication of tuberculosis (TB). It has not been reported in the United Kingdom or the United States, or, to our knowledge, in non-Asian patients. We have identified seven cases of patients presenting to a single teaching hospital in the northwest of England over a 13-year period. Only one patient had a history of TB, but six of the seven patients had a history of occupational dust exposure, including one patient with pneumoconiosis. It is possible that anthracofibrosis is an exaggerated endobronchial form of the much more common condition of anthracosis in coal miners and other workers who have been exposed to mineral dusts. Our study suggests that this is essentially a benign condition, although it may progress very slowly, leading to gradually progressive bronchial stenosis. The diagnosis is important because most patients have clinical, radiologic, and bronchoscopic changes that are highly suspicious of malignancy.

Reversible pulmonary artery perfusion abnormalities in the postpartum period as a precursor to the development of pulmonary arterial hypertension.

Deterioration, or a new presentation, of pulmonary arterial hypertension (PAH), are recognized complications of pregnancy. In this report, we describe a patient with a family history of PAH who developed peripartum breathlessness and hypoxemia with ventilation-perfusion mismatch but no evidence of thromboembolism or PAH. Significantly reduced perfusion at both lung bases was noted on perfusion scintigraphy and three-dimensional magnetic resonance (3D-MR) perfusion maps in the immediate postpartum period. These abnormalities spontaneously resolved by 16 weeks postpartum, consistent with reversible pulmonary abnormalities of pulmonary perfusion. However, she developed new breathlessness four years later and was found to have developed PAH. This case provides a mechanism which may contribute to the high mortality seen in pregnant patients with PAH in the peripartum period.

Effects of equipment and technique on peak flow measurements.

BACKGROUND: Different lung function equipment and different respiratory manoeuvres may produce different Peak Expiratory Flow (PEF) results. Although the PEF is the most common lung function test, there have been few studies of these effects and no previous study has evaluated both factors in a single group of patients. METHODS: We studied 36 subjects (PEF range 80-570 l/min). All patients recorded PEF measurements using a short rapid expiration following maximal inspiration (PEF technique) or a forced maximal expiration to residual volume (FVC technique). Measurements were made using a Wright's peak flow meter, a turbine spirometer and a Fleisch pneumotachograph spirometer. RESULTS: The mean PEF was 8.7% higher when the PEF technique was used (compared with FVC technique, p < 0.0001). The mean PEF recorded with the turbine spirometer was 5.5% lower than the Wright meter reading. The Fleisch spirometer result was 19.5% lower than the Wright reading. However, adjustment of the Wrights measurements from the traditional Wright's scale to the new EU Peak Flow scale produced results that were only 7.2% higher than the Fleisch pneumotachograph measurements. CONCLUSION: Peak flow measurements are affected by the instruction given and by the device and Peak Flow scale used. Patient management decisions should not be based on PEF measurement made on different instruments.

A study of attitudes, beliefs and organisational barriers related to safe emergency oxygen therapy for patients with COPD (chronic obstructive pulmonary disease) in clinical practice and research.

BACKGROUND: Patients can be harmed by receiving too little or too much oxygen. There is ongoing disagreement about the use of oxygen in medical emergencies. METHODS: This was a mixed methods study (survey, telephone interviews and focus groups) involving patients, the public and healthcare professionals (HCPs). RESULTS: 62 patients with chronic obstructive pulmonary disease (COPD), 65 members of the public, 68 ambulance crew members, 22 doctors, 22 nurses and 10 hospital managers took part. For five factual questions about oxygen therapy, the average score for correct answers was 28% for patients with COPD, 33% for the general public and 75% for HCPs. The HCPs had an average score of 66% for five technical questions. Patients (79%) and members of the public (68%) were more likely than HCPs (36%) to believe that oxygen was beneficial in most medical emergencies and less likely to have concerns that it might harm some people (35%, 25% and 68%). All groups had complex attitudes about research into oxygen use in medical emergencies. Many participants would not wish for themselves or their loved ones to have their oxygen therapy determined by a randomised protocol, especially if informed consent was not possible in an emergency situation. CONCLUSIONS: We have found low levels of factual knowledge about oxygen use among patients with COPD and the general public and many false beliefs about the potential benefits and harms of using oxygen. HCPs had a higher level of factual knowledge. All groups had complex attitudes towards research into emergency oxygen use.

Mold sensitization is common amongst patients with severe asthma requiring multiple hospital admissions.

BACKGROUND: Multiple studies have linked fungal exposure to asthma, but the link to severe asthma is controversial. We studied the relationship between asthma severity and immediate type hypersensitivity to mold (fungal) and non-mold allergens in 181 asthmatic subjects. METHODS: We recruited asthma patients aged 16 to 60 years at a University hospital and a nearby General Practice. Patients were categorized according to the lifetime number of hospital admissions for asthma (82 never admitted, 53 one admission, 46 multiple admissions). All subjects had allergy skin prick tests performed for 5 mold allergens (Aspergillus, Alternaria, Cladosporium, Penicillium and Candida) and 4 other common inhalant allergens (D. pteronyssinus, Grass Pollen, Cat and Dog). RESULTS: Skin reactivity to all allergens was commonest in the group with multiple admissions. This trend was strongest for mold allergens and dog allergen and weakest for D. pteronyssinus. 76% of patients with multiple admissions had at least one positive mold skin test compared with 16%-19% of other asthma patients; (Chi squared p < 0.0001). Multiple mold reactions were also much commoner in the group with multiple admissions (50% V 5% and 6%; p < 0.0001). The number of asthma admissions was related to the number and size of positive mold skin allergy tests (Spearman Correlation Coefficient r = 0.60, p < 0.0001) and less strongly correlated to the number and size of non-mold allergy tests (r = 0.34, p = 0.0005). Hospital admissions for asthma patients aged 16-40 were commonest during the mold spore season (July to October) whereas admissions of patients aged above 40 peaked in November-February (Chi Squared, p < 0.02). CONCLUSION: These findings support previous suggestions that mold sensitization may be associated with severe asthma attacks requiring hospital admission.

Is nebulized saline a placebo in COPD?

BACKGROUND: Many trials of nebulized therapy have used nebulized saline as a "placebo". However, nebulized isotonic saline is sometimes used to assist sputum expectoration and relieve breathlessness in COPD patients. We designed this study to establish if nebulized saline had a placebo effect or a clinical effect. METHODS: 40 patients were studied following hospital admission for exacerbated COPD (mean FEV1 30% predicted). Patients were randomised to single-blind administration of either 4 mls of nebulized isotonic saline using an efficient nebulizer (active group n = 20) or an inefficient nebulizer (placebo group n = 20). Spirometry and subjective breathlessness scores (Modified Likert Scale) were measured before nebulized treatment and 10 minutes after treatment. RESULTS: There was no significant change in FEV1 after active or placebo nebulized saline treatment. Patients reported a 4% improvement in mean breathlessness score following placebo (Wilcoxon test; p = 0.37) compared with 23% improvement following active nebulized saline (p = 0.0001). 65% of patients given active nebulized saline but only 5% of the placebo group reported that mucus expectoration was easier after the treatment. CONCLUSIONS: This study lends support to the current use of nebulized saline to relieve breathlessness (possibly by facilitating sputum clearance) in COPD patients. Lung function was not affected. Nebulized saline can therefore be used as a placebo in bronchodilator studies involving COPD patients but it cannot be used as a placebo in trials assessing symptom relief.