Emergency oxygen therapy for the breathless patient. Guidelines prepared by North West Oxygen Group

Impact of Using a Non-Rebreathing Mask in Patients With Respiratory Failure

BACKGROUND

Liberal oxygen therapy might increase the mortality rate of patients. Non-rebreathing masks (NRM) are a high-flow, non-invasive oxygen device that can provide oxygen concentration up to 95%. This study aimed to determine the impact of using NRM in patients with respiratory failure.

METHODS

This retrospective cohort study was conducted in four medical institutions in Taiwan from January 2010 to December 2016. The association between mortality and NRM use before receiving ventilator support in patients with respiratory failure in the emergency department was analyzed. Patients were divided into the NRM treatment and no NRM treatment groups. A 1:4 propensity score matching was conducted. Regarding the duration of NRM use, treatments were grouped as 0 h, 0-1 h, 1-2 h, and >2 h.

RESULTS

A total of 18,749 patients were included, with 1074 using NRM. After propensity score matching, 1028 patients using NRM (0-1 h: 508, 1-2 h: 193, and >2 h: 327) and 4112 patients not using NRM were analyzed. The 30-day mortality rates were 29.1%, 28.5%, 27.5%, and 35.5% in the 0 h, 0-1 h, 1-2 h, and >2 h treatment groups, respectively. Patients with respiratory failure due to pulmonary disease using NRM over 2 h had a higher mortality rate than patients not using NRM (hazard ratio: 1.3, 95% CI: 1.01-1.66).

CONCLUSIONS

Prolonged use of NRM in patients with respiratory failure due to pulmonary disease possibly increases mortality.

Oxygen therapy in the pre-hospital setting for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a global leading cause of morbidity and mortality, characterised by acute deterioration in symptoms. During these exacerbations, people are prone to developing alveolar hypoventilation, which may be partly caused by the administration of high inspired oxygen concentrations.

OBJECTIVES

To determine the effect of different inspired oxygen concentrations ("high flow" compared to "controlled") in the pre-hospital setting (prior to casualty/emergency department) on outcomes for people with acute exacerbations of COPD (AECOPD).

SEARCH METHODS

The Cochrane Airways Group Specialised Register, reference lists of articles and online clinical trial databases were searched. Authors of identified randomised controlled trials (RCTs) were also contacted for details of other relevant published and unpublished studies. The most recent search was conducted on 16 September 2019.

SELECTION CRITERIA

We included RCTs comparing oxygen therapy at different concentrations or oxygen therapy versus placebo in the pre-hospital setting for treatment of AECOPD.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The primary outcome was all-cause and respiratory-related mortality.

MAIN RESULTS

The search identified a total of 824 citations; one study was identified for inclusion and two studies are awaiting classification. The 214 participants involved in the included study were adults with AECOPD, receiving treatment by paramedics en route to hospital. The mean age of participants was 68 years. A reduction in pre/in-hospital mortality was observed in favour of the titrated oxygen group (two deaths in the titrated oxygen group compared to 11 deaths in the high-flow control arm; risk ratio (RR) 0.22, 95% confidence interval (CI) 0.05 to 0.97; 214 participants). This translates to an absolute effect of 94 per 1000 (high-flow oxygen) compared to 21 per 1000 (titrated oxygen), and a number needed to treat for an additional beneficial outcome (NNTB) of 14 (95% CI 12 to 355) with titrated oxygen therapy. Other than mortality, no other adverse events were reported in the included study. Wide confidence intervals were observed between groups for arterial blood gas (though this may be confounded by protocol infidelity in the included study for this outcome measure), treatment failure requiring invasive or non-invasive ventilation or hospital utilisation. No data were reported for quality of life, lung function or dyspnoea. Risk of bias within the included study was largely unclear, though there was high risk of bias in domains relating to performance and attrition bias. We judged the evidence to be of low certainty, according to GRADE criteria.

AUTHORS' CONCLUSIONS

The one included study found a reduction in pre/in-hospital mortality for the titrated oxygen arm compared to the high-flow control arm. However, the paucity of evidence somewhat limits the reliability of these findings and generalisability to other settings. There is a need for robust, well-designed RCTs to further investigate the effect of oxygen therapies in the pre-hospital setting for people with AECOPD.

Automaticversusmanual oxygen administration in the emergency department

Oxygen is commonly administered in hospitals, with poor adherence to treatment recommendations.

We conducted a multicentre randomised controlled study in patients admitted to the emergency department requiring O2≥3 L·min−1. Patients were randomised to automated closed-loop or manual O2titration during 3 h. Patients were stratified according to arterial carbon dioxide tension (PaCO2) (hypoxaemicPaCO2≤45 mmHg; or hypercapnicPaCO2>45–≤55 mmHg) and study centre. Arterial oxygen saturation measured by pulse oximetry (SpO2) goals were 92–96% for hypoxaemic, or 88–92% for hypercapnic patients. Primary outcome was % time withinSpO2target. Secondary endpoints were hypoxaemia and hyperoxia prevalence, O2weaning, O2duration and hospital length of stay.

187 patients were randomised (93 automated, 94 manual) and baseline characteristics were similar between the groups. Time within theSpO2target was higher under automated titration (81±21%versus51±30%, p<0.001). Time with hypoxaemia (3±9%versus5±12%, p=0.04) and hyperoxia under O2(4±9%versus22±30%, p<0.001) were lower with automated titration. O2could be weaned at the end of the study in 14.1%versus4.3% patients in the automated and manual titration group, respectively (p<0.001). O2duration during the hospital stay was significantly reduced (5.6±5.4versus7.1±6.3 days, p=0.002).

Automated O2titration in the emergency department improved oxygenation parameters and adherence to guidelines, with potential clinical benefits.

Cardiac responses to 24 hrs hyperoxia in Bmp2 and Bmp4 heterozygous mice

BACKGROUND

Hyperoxia or clinical oxygen (O2) therapy is known to result in increased oxidative burden. Therefore, understanding susceptibility to hyperoxia exposure is clinically important. Bone morphogenetic proteins (BMPs) 2 and 4 are involved in cardiac development and may influence responses to hyperoxia.

METHODS

Bmp2(+/)(-). Bmp4(+/)(-) and wild-type mice were exposed to hyperoxia (100% O2) for 24 hrs. Electrocardiograms (ECG) were recorded before and during exposure by radio-telemetry.

RESULTS

At baseline, a significantly higher low frequency (LF) and total power (TP) heart rate variability (HRV) were found in Bmp2(+/)(-) mice only (p < 0.05). Twenty-four hours hyperoxia-induced strain-independent reductions in heart rate, QTcB and ST-interval and increases in QRS, LF HRV and standard deviation of RR-intervals were observed. In Bmp4(+/)(-) mice only, increased PR-interval (PR-I) (24 hrs), P-wave duration (P-d; 18 and 21-24 hrs), PR-I minus P-d (PR - Pd; 24 hrs) and root of the mean squared differences of successive RR-intervals (24 hrs) were found during hyperoxia (p < 0.05).

DISCUSSION

Elevated baseline LF and TP HRV in Bmp2(+/)(-) mice suggests an altered autonomic nervous system regulation of cardiac function in these mice. However, this was not related to strain specific differences in responses to 24 hrs hyperoxia. During hyperoxia, Bmp4(+/-) mice were the most susceptible in terms of atrioventricular conduction changes and risk of atrial fibrillation, which may have important implications for patients treated with O2 who also harbor Bmp4 mutations. This study demonstrates significant ECG and HRV responses to 24 hrs hyperoxia in mice, which highlights the need to further work on the genetic mechanisms associated with cardiac susceptibility to hyperoxia.

Supplemental oxygen therapy: Important considerations in oral and maxillofacial surgery

The administration of supplemental oxygen is an essential element of appropriate management for a wide range of clinical conditions; crossing different medical and surgical specialities. The present review summarizes the role of supportive oxygen therapy in various clinical conditions encountered in our day-to-day practice in the speciality of oral and maxillofacial surgery; including major trauma, shock, sepsis; perioperative and postoperative considerations and in patients with various other medical comorbidities. Regular and judicious use of oxygen as a drug is thus recommended in our day-to-day practice in oral and maxillofacial surgery to reduce the morbidity and improve the prognosis of patients.

Emergency oxygen use in adult patients: concise guidance

There is considerable controversy concerning the benefits and risks of oxygen treatment in many situations and healthcare professionals receive conflicting advice about safe oxygen use. The British Thoracic Society (BTS) has published up-to-date, evidence-based guidelines for emergency oxygen use in the UK in order to encourage the safe use of oxygen in emergency situations and improve consistency of clinical practice. The purpose of this concise guideline is to summarise the key recommendations, particularly concerning emergency oxygen use in the hospital setting.

Critical care nurses' opinion and self-reported practice of oxygen therapy: a survey

BACKGROUND

Critical care nurses frequently and independently manage oxygen therapy. Despite the importance of oxygen therapy, there is limited evidence to inform or support critical care nurses' oxygen therapy practices.

AIM

To establish if there is variability in oxygen therapy practices of critical care nurses and examine the degree of variability.

METHOD

On-line questionnaire of ACCCN members between April and June 2010.

RESULTS

The response rate was 36% (542/1523 critical care nurses). Overall, 378 (70%) respondents practiced in metropolitan critical care units; 278 (51%) had ≥14 years of specialty practice. In response to falling SpO(2), 8.9% of nurses would never escalate oxygen therapy without a doctor's request, and 51% of nurses would not routinely escalate oxygen therapy in the absence of medical orders. Only 56% of nurses reported always increasing FiO(2) prior to endotracheal suctioning. In mechanically ventilated patients, 33% of nurses believed oxygen toxicity was a greater threat to lung injury than barotrauma. More than >60% of respondents reported a tolerance for a stable SpO(2) of 90%. Nurses in rural critical care units were less likely to independently titrate oxygen to their own target SpO(2), but more likely to independently treat a falling SpO(2) with higher FiO(2).

CONCLUSION

Critical care nurses varied in their self-reported oxygen therapy practices justifying observational and interventional studies aimed at improving oxygen therapy for critically ill patients.

Understanding the effects of oxygen administration in haemorrhagic shock

AIMS AND OBJECTIVES

the aim of this article is to provide a review of the literature regarding oxygen administration and the use of oxygen in patients experiencing haemorrhagic shock (HS).

RESULTS

oxygen is administered to patients to assist them in maintaining oxygenation. The administration of oxygen is complex and varies significantly among patients. In order to optimize patient care, clinicians need to be aware of the potential effects, both beneficial and harmful, that oxygen can have on the body.

INCLUSION AND EXCLUSION CRITERIA

literature inclusion criteria for this article was any article (1995 to present) pertaining to oxygen administration and HS. Also included were articles related to tissue injury caused by an overabundance of free radicals with the administration of oxygen. Articles related to oxygen and wound healing, pollution, aerospace, food and industrial uses were excluded.

CONCLUSIONS

this review of the literature provides an overview of the use of oxygen in clinical practice and HS. The harmful effects of oxygen are highlighted to alert the clinician to this potential when there is an overabundance of oxygen.

RELEVANCE TO CLINICAL PRACTICE

oxygen is one of the most common drugs used in the medical community; however, the effects of oxygen on the body are not well understood. The use of oxygen if not prescribed correctly can cause cellular damage and death. Clinicians need to be more aware of the effects of oxygen and the damage it may cause if not administered properly.

A guideline-based decision support system for generating referral recommendations from routinely recorded home telehealth measurement data

The objectives of this paper are to present a guideline-based decision support system (GBDSS) design for supporting patient telehealth management of chronic disease and to test its performance in correctly making referral recommendations using routinely recorded measurement data from home telehealth recordings. The GBDSS has been developed to manage lung disease patients in a home telehealth environment. The system operates by checking the availability of home telehealth measurement data on a daily basis, interprets these data using a rule-based decision tree classification, and ultimately generates referral recommendations based on these measured data. The system has demonstrated discriminative power when applied in the analysis of retrospective telehealth data, as a surrogate for realtime referral generation. To this end a telehealth dataset comprising 16 chronic obstructive pulmonary disease (COPD) patients monitored over a 12 month period was used. It was shown that GBDSS referral recommendations could help reduce the number of cases that required a carer's urgent attention by 72.1%, with 81.9% accuracy, 80.8% specificity and 90.4% sensitivity.

An audit of oxygen therapy on a respiratory ward

Oxygen therapy can be a life-saving intervention, which is widely available and commonly prescribed by medical staff. Patients often receive oxygen therapy in hospital but, like any other drug, oxygen can be dangerous when given in the wrong concentration.

AIMS

To review the current literature. To examine current prescribing practice plus methods of oxygen delivery on a respiratory ward.

METHOD

A prospective audit was conducted on patients receiving oxygen therapy over a 4-week period. The ward was audited pre- and post-education sessions. Education was on oxygen prescribing and oxygen therapy.

RESULTS

The literature revealed that oxygen was often poorly prescribed by doctors and at times poorly administered by nurses. Of the 55 patients audited pre-education, only 5% of patients had a prescription. This increased to 20% post-education (P=0.042). The initial audit uncovered 14 issues surrounding oxygen delivery. This fell to one post-education (P<0.001). Reassuringly, all patients had arterial oxygen saturation recorded.

CONCLUSION

Current rates of oxygen prescribing remain unsatisfactory despite doctors being made aware of the audit findings. Education on oxygen therapy improved the delivery of oxygen therapy to patients on a respiratory ward.

The effect of education on hypothetical and actual oxygen administration decisions

AIM

This study examined the effect of an education intervention on emergency nurses' decisions related to oxygen administration.

METHOD

A controlled pre-test/post-test quasi-experimental design was used. The intervention was a written self directed learning package. Outcome measures were (i) factual knowledge measured using parallel form multiple choice questions (MCQs) and (ii) clinical decisions measured using parallel form MCQs, parallel form patient scenarios and clinical practice observation.

RESULTS

Eighty-eight nurses from 4 Melbourne EDs participated in the study (control group: n=37 and experimental group: n=51). Subgroups of nurses from the experimental group also participated in the patient scenarios (n=20) and clinical practice observation (n=10). Emergency nurses' knowledge increased as a function of education. Both patient scenario data and clinical practice observation showed decreased selection of nasal cannulae, increased selection of air entrainment masks and a trend towards selection of higher oxygen flow rates following education.

CONCLUSIONS

Evaluation of educational interventions in nursing should focus on identifying strategies that enhance learning in a clinical environment, are valid in terms of the clinical context and culture in which they are being used and most importantly, produce sustained improvements in actual clinical practice.

Oxygen alert cards and controlled oxygen: preventing emergency admissions at risk of hypercapnic acidosis receiving high inspired oxygen concentrations in ambulances and A&E departments

BACKGROUND

Appropriate resuscitation of hypoxic patients is fundamental in emergency admissions. To achieve this, it is standard practice of ambulance staff to administer high concentrations of oxygen to patients who may be in respiratory distress. A proportion of patients with chronic respiratory disease will become hypercapnic on this.

OBJECTIVES AND METHODS

A scheme was agreed between the authors' hospital and the local ambulance service, whereby patients with a history of previous hypercapnic acidosis with a Pao2 >10.0 kPa--indicating that oxygen may have worsened the hypercapnia--are issued with "O2 Alert" cards and a 24% Venturi mask. The patients are instructed to show these to ambulance and A&E staff who will then use the mask to avoid excessive oxygenation. The scheme was launched in 2001 and this paper present the results of an audit of the scheme in 2004.

RESULTS

A total of 18 patients were issued with cards, and 14 were readmitted on 69 occasions. Sufficient documentation for auditing purposes was available for 52 of the 69 episodes. Of these audited admissions, 63% were managed in the ambulance, in line with card-holder protocol. This figure rose to 94% in the accident and emergency department.

CONCLUSION

These data support the usability of such a scheme to prevent iatrogenic hypercapnia in emergency admissions.

Oxygen therapy in the pre-hospital setting for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality in the developed world, is characterised by acute deterioration in symptoms. During these exacerbations, people are prone to developing alveolar hypoventilation, which may be contributed to by the administration of high inspired oxygen concentrations.

OBJECTIVES

The objective of the review was to determine the effect of different inspired oxygen concentrations ("high flow" compared to "controlled") in the pre-hospital setting on outcome for people with acute exacerbations of COPD.

SEARCH STRATEGY

We searched the Cochrane Airways Group Specialised Register (August 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to August 2005), EMBASE (1980 to wk 32, 2005), CINAHL (1982 to August wk 1, 2005) and reference lists of articles. We also contacted authors of identified RCTs for details of other relevant, published and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing oxygen therapy at different concentrations or oxygen therapy versus placebo in the pre-hospital setting for treatment of acute exacerbations of COPD were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

The search identified a total of 741 abstracts, of which 18 were selected as potentially relevant, only two of the 18 studies were randomised controlled trials and eligible for inclusion in the review, but were ongoing and had no data available for analysis.

AUTHORS' CONCLUSIONS

No relevant trials have been published to date, so there is no evidence to indicate whether different oxygen therapies in the pre-hospital setting have an effect on outcome for people with acute exacerbations of COPD. There is an urgent need for robust, well-designed randomised controlled trials to investigate the effect of oxygen therapies in the pre-hospital setting for people with acute exacerbations of COPD.

The effects of specific educational preparation on emergency nurses' clinical decisions regarding supplemental oxygen administration

The use of supplemental oxygen by emergency nurses has important implications for patient outcomes, yet there is significant variability in oxygen administration practises. Specific education related to oxygen administration increases factual knowledge in this domain; however, the impact of knowledge acquisition on nurses' clinical decisions is poorly understood. This study aimed to examine the effect of educational preparation on 20 emergency nurses' decisions regarding the assessment of oxygenation and the use of supplemental oxygen. A pre-test/post-test, quasi-experimental design was used. The intervention was a written, self-directed learning package. The major effects of the completion of the learning package included no change in the number or types of parameters used by nurses to assess oxygenation, a significant decrease in the selection of simple masks, a significant increase in the selection of air entrainment masks, fewer hypothetical outcomes of unresolved respiratory distress and more hypothetical outcomes of decreased respiratory distress. As many nursing education programs are aimed at increasing factual knowledge, while experience remains relatively constant, a greater understanding of the relationship between factual knowledge and clinical decisions is needed if educational interventions are to improve patient outcomes.

Capillary blood gases in acute exacerbations of COPD

OBJECTIVES

To assess the correlation and agreement between measurements of PO(2), PCO(2), H(+) and HCO(3)(-) in arterial and capillary blood in patients with acute exacerbations of COPD. To assess the repeatability of capillary measurements.

DESIGN

Method comparison study.

SETTING

Accident and emergency department in a university teaching hospital.

MAIN OUTCOME MEASURES

Measurements of PO(2), PCO(2), H(+) and HCO(3)(-) in one arterial and two capillary samples taken from consecutive patients with acute exacerbations of COPD.

RESULTS

The agreement between measurements of PCO(2), H(+) and HCO(3)(-) in arterial and capillary blood was good with mean differences of 0.087 kPa, 1.044 nmol/l and 0.513 mmol/l, respectively. The corresponding 95% limits of agreement were narrow. The agreement between measurements of PO(2) was poor with a mean difference of 1.256 kPa and wide 95% limits of agreement. There was good repeatability between capillary samples with mean differences of 0.094 kPa, 0.674 nmol/l and 0.028 mmol/l for measurements of PCO(2), H(+) and HCO(3) respectively and narrow coefficients of repeatability.

CONCLUSIONS

Capillary blood gas measurements provide an accurate assessment of PCO(2), H(+) and HCO(3)(-) and can be used to reliably measure the ventilatory status of patients. Combined with continuous pulse oximetry they can be used as an alternative to arterial blood gas measurements in patients with acute exacerbations of COPD.

Oxygen: kill or cure? Prehospital hyperoxia in the COPD patient

High concentration oxygen therapy has long been a mainstay of prehospital treatment. Guidelines for its administration have for many years also cautioned its use with patients with chronic obstructive pulmonary disease (COPD). Successive guidelines and prehospital textbooks have advocated the use of 28% oxygen masks and re-emphasised the importance of the dangers of hyperoxia, often drawing upon the classic theory of hypoxic drive. Despite this, the reality remains that ambulance crews have tended to overoxygenate such patients. One study demonstrated that 80% of patients sampled with acute exacerbation of their COPD received oxygen in excess of 28% from the ambulance crew. Is this a worrying development or a reassuring sign that prehospital providers are rightly more concerned about the dangers of hypoxia than hyperoxia? And if the guidelines are right, then how are the hearts and minds of ambulance paramedics and technicians won?

Effect of a self-directed learning package on emergency nurses' knowledge of assessment of oxygenation and use of supplemental oxygen

Emergency nurses frequently and independently make decisions regarding supplemental oxygen. The importance of these decisions for patients is highlighted by the well documented association between respiratory dysfunction and adverse events. This study aimed to: (i) examine the effect of educational preparation on emergency nurses' knowledge of assessment of oxygenation, and the use of supplemental oxygen; (ii) explore the impact of existing knowledge on decisions related to the implementation of supplemental oxygen; and (iii) explore nurses' characteristics that were associated with effectiveness of the educational preparation. A pretest/post-test, controlled, quasi-experimental design was used in this study. Educational preparation was effective in increasing emergency nurses' knowledge. Baseline level of knowledge was predictive of reports of independent decisions regarding the implementation of oxygen. There was a significant positive relationship between postgraduate qualification in emergency nursing and the effect of education, and significant negative relationships between effect of education and baseline level of knowledge and daily decisions to implement supplemental oxygen.

Initial oxygen management in patients with an exacerbation of chronic obstructive pulmonary disease

BACKGROUND

The Norfolk and Norwich University Hospital (NNUH) is situated in rural Norfolk, and ambulance journey times are often >30 min. Longer ambulance journeys could lead to a greater risk of hypercapnia, if inappropriately high concentrations of oxygen are given during an exacerbation of COPD.

AIM

To investigate the effect of high concentration oxygen (HCO, FiO(2) > 0.28) on COPD patients, and the outcome of instituting a simple protocol to reduce such exposure.

DESIGN

Retrospective audit.

METHOD

An audit was conducted of all patients admitted with an exacerbation of COPD to the NNUH during the 2 months from 1 December 2001 to 31 January 2002 (n = 108). Results were shared with paramedics, and guidelines agreed for the initial provision of lower concentrations of oxygen (LCO, FiO(2) < or = 0.28). A second audit was conducted a year later between 1 December 2002 and 31 January 2003 (n = 103).

RESULTS

HCO caused significant (p < 0.01) acidosis and inappropriately high PaO(2) and PaCO(2), compared to initial LCO therapy. There was a significantly increased complication rate during admission (p < 0.01) in those COPD patients receiving HCO compared to LCO, particularly when ambulance journeys exceeded 30 min. The second audit demonstrated a significant (p < 0.001) reduction in the number of patients initially receiving HCO, but the complication rate was unaltered.

DISCUSSION

A simple intervention, such as providing paramedics with 28% Venturi masks, can reduce the number of COPD patients exposed to HCO. A randomized controlled trial is long overdue to establish whether HCO or LCO as initial management is associated with the most favourable prognosis in different hospital settings.