Adjuvant High-Flow Normobaric Oxygen After Mechanical Thrombectomy for Anterior Circulation Stroke: a Randomized Clinical Trial

Adjuvant neuroprotective therapies for acute ischemic stroke (AIS) have demonstrated benefit in animal studies, albeit without human translation. We investigated the safety and efficacy of high-flow normobaric oxygen (NBO) after endovascular recanalization in anterior circulation stroke. This is a prospective randomized controlled study. Eligible patients were randomized to receive high-flow NBO by a Venturi mask (FiO2 50%, flow 15 L/min) or routine low-flow oxygen supplementation by nasal cannula (flow 3 L/min) after vessel recanalization for 6 h. Patient demographics, procedural metrics, complications, functional outcomes, symptomatic intracranial hemorrhage (sICH), and infarct volume were assessed. A total of 91 patients were treated with high-flow NBO. NBO treatment revealed a common odds ratio of 2.2 (95% CI, 1.26 to 3.87) favoring the distribution of global disability scores on the mRS at 90 days. The mortality at 90 days was significantly lower in the NBO group than in the control group, with an absolute difference of 13.86% (rate ratio, 0.35; 95% CI, 0.13-0.93). A significant reduction of infarct volume as determined by MRI was noted in the NBO group. The median infarct volume was 9.4 ml versus 20.5 ml in the control group (beta coefficient, - 20.24; 95% CI, - 35.93 to - 4.55). No significant differences were seen in the rate of sICH, pneumonia, urinary infection, and seizures between the 2 groups. This study suggests that high-flow NBO therapy after endovascular recanalization is safe and effective in improving functional outcomes, decreasing mortality, and reducing infarct volumes in anterior circulation stroke patients within 6 h from stroke onset.

Apneic oxygenation is associated with a reduction in the incidence of hypoxemia during the RSI of patients with intracranial hemorrhage in the emergency department

Critically ill patients undergoing emergent intubation are at risk of oxygen desaturation during the management of their airway. Patients with intracranial hemorrhage (ICH) are particularly susceptible to the detrimental effects of hypoxemia. Apneic oxygenation (AP OX) may be able to reduce the occurrence of oxygen desaturation during the emergent intubation of these patients. We sought to assess the effect AP OX on oxygen desaturation during the rapid sequence intubation (RSI) of patients with ICH in the emergency department (ED). We prospectively collected data on all patients intubated in an urban academic ED over the 2-year period from July 1, 2013 to June 30, 2015. Following each intubation, the operator completed a standardized continuous quality improvement (CQI) data form, which included information on patient, operator and intubation characteristics. Operators recorded data on the use of AP OX, the oxygen flow rate used for AP OX, and the starting and lowest saturations during intubation. Adult patients with ICH who underwent RSI by emergency medicine (EM) residents were included in the analyses. The primary outcome variable was any oxygen saturation <90 % during the intubation. We performed a backward stepwise multivariate logistic regression analysis to identify variables associated with oxygen desaturation. The primary independent variable of interest was the use of AP OX during the intubation. Inclusion criteria for the study was met by 127 patients. AP OX was used in 72 patients (AP OX group) and was not used in 55 patients (NO AP OX group). The incidence of desaturation was 5/72 (7 %) in the AP OX group and was 16/55 (29 %) in the NO AP OX group. In the multivariate logistic regression analysis the use of AP OX was associated with a reduced odds of desaturation (aOR 0.13; 95 % CI 0.03-0.53). Patients with ICH who received AP OX during RSI in the ED were seven times less likely to have an oxygen saturation of <90 % during the intubation compared to patients who did not receive AP OX. AP OX is a simple intervention that may minimize the risk of oxygen desaturation during the RSI of patients with ICH.

Prehospital oxygen administration for chest pain patients decreases significantly following implementation of the 2010 AHA guidelines

OBJECTIVES

The purpose of this study was to examine trends in oxygen administration following the 2010 American Heart Association guidelines recommendation to withhold oxygen therapy for patients with uncomplicated presentations of ACS whose SpO2 is 94% or higher.

METHODS

Following IRB review and approval, we performed a retrospective analysis of data obtained from Fisdap(TM), a national, clinical skills tracking system for paramedic students between June 2010 and December 2012. Inclusion criteria included: 1) student consent for research, 2) cardiac chest pain recorded as the chief complaint, and 3) SpO2 data available for review. O2 administration, route, and dose were abstracted, and the percent of patient encounters with oxygen administration was calculated for each year. Unadjusted logistic regression was used to determine if O2 administration rates changed significantly over the study period. Unadjusted logistic regression was also used to determine if there was a difference in the odds of receiving oxygen based on a patient's SpO2 value.

RESULTS

10,552 patient encounters by 2,447 paramedic students from 195 paramedic programs representing 49 states were included for analysis. Prior to release of the new guidelines (2010), 71.9% (95% CI 69.8-74.0%) of patients with SpO2 ≥ 94% received supplemental O2. Rates of O2 administration were significantly lower in 2011 (64%; 95% CI 62.7-65.3%) and in 2012 (53.1%; 95% CI 51.5-54.7). The odds of a hemodynamically stable chest pain patient with SpO2 ≥ 94% receiving supplemental oxygen in 2011 were 1.4 times lower compared to patients in 2010 (95% CI 1.3-1.6). Similarly, the odds of patients in 2012 receiving supplemental oxygen were 2.3 times lower compared to patients in 2010 (95% CI 2.0-2.6). The odds of receiving supplemental oxygen decreased by 4% for each 1% increase in SpO2 beyond the 94% threshold (OR = 0.96; 95% CI 0.94-0.98).

CONCLUSIONS

The prehospital administration of supplemental O2 decreased significantly following release of the 2010 updated guidelines; however, our data revealed that 50% of patients not meeting criteria for administration still received supplemental O2.

Hyperoxemia and long-term outcome after traumatic brain injury

INTRODUCTION

The relationship between hyperoxemia and outcome in patients with traumatic brain injury (TBI) is controversial. We sought to investigate the independent relationship between hyperoxemia and long-term mortality in patients with moderate-to-severe traumatic brain injury.

METHODS

The Finnish Intensive Care Consortium database was screened for mechanically ventilated patients with a moderate-to-severe TBI. Patients were categorized, according to the highest measured alveolar-arterial O₂ gradient or the lowest measured PaO₂ value during the first 24 hours of ICU admission, to hypoxemia (<10.0 kPa), normoxemia (10.0 to 13.3 kPa) and hyperoxemia (>13.3 kPa). We adjusted for markers of illness severity to evaluate the independent relationship between hyperoxemia and 6-month mortality.

RESULTS

A total of 1,116 patients were included in the study, of which 16% (n = 174) were hypoxemic, 51% (n = 567) normoxemic and 33% (n = 375) hyperoxemic. The total 6-month mortality was 39% (n = 435). A significant association between hyperoxemia and a decreased risk of mortality was found in univariate analysis (P = 0.012). However, after adjusting for markers of illness severity in a multivariate logistic regression model hyperoxemia showed no independent relationship with 6-month mortality (hyperoxemia vs. normoxemia OR 0.88, 95% CI 0. 63 to 1.22, P = 0.43; hyperoxemia vs. hypoxemia OR 0.97, 95% CI 0.63 to 1.50, P = 0.90).

CONCLUSION

Hyperoxemia in the first 24 hours of ICU admission after a moderate-to-severe TBI is not predictive of 6-month mortality.

Long-term oxygen therapy in Japan: history, present status, and current problems

Historically, the progress of long term-oxygen therapy (LTOT) in Japan has been characterized by collaboration among academic groups, policy makers, and industrial companies. The public health insurance program has covered the cost of LTOT since 1985. Thomas Petty's group in Denver enthusiastically carried out the public implementation of LTOT and conveyed the concept of pulmonary rehabilitation for the processing with LTOT. Although the target diseases of LTOT in Japan tended to be chronic obstructive pulmonary disease or sequelae of primary lung tuberculosis, it was soon applied for cardiac diseases as well as other pulmonary diseases. Together with increasing medical costs for geriatric patients, the political conversion from hospital based care of a traditional style to home care system has been performed, with two background reasons: the improvement of quality of life of patients and the reduction of the medical expense. Presently, LTOT plays a pivotal role in the successful implementation of home respiratory care for elderly patients. In addition, this promotes comprehensive pulmonary rehabilitation, a team approach, and close liaisons between primary care and hospitals. Currently, the total number of patients using LTOT exceeds 150,000. In Japan, LTOT resulted in an advancement in the medical care as well as in administrative decision to introduce it as a nationwide system after analyzing the results of opinion polls of patients with respiratory failure. However, the recent great earthquake in East Japan revealed that many unresolved problems remain for these patients, and these issues are of great concern.

Factors predicting prolonged hospital stay for infants with bronchiolitis

BACKGROUND

Prior prediction models for length of stay (LOS) in bronchiolitis have focused more on birth- and disease-related risk factors than on early hospital course factors, particularly common clinical markers including respiratory status and caloric intake.

OBJECTIVES

1) Study the associations of various clinical markers and LOS; and 2) develop a LOS prediction model.

DESIGN

Retrospective cohort study.

SETTING

Children's Hospital of Wisconsin.

PATIENTS

Inclusion criteria were: age < 365 days old; admission between November 1, 2004 and April 15, 2005; final diagnosis of bronchiolitis; placement on the bronchiolitis treatment protocol; and lack of concurrent condition impacting LOS.

RESULTS

During the study period, 272/347 infants admitted with bronchiolitis met inclusion criteria. On hospital day 2, infants in the prolonged LOS group (≥ 108 hours) had a significantly greater number of hours on supplemental oxygen, maximum supplemental oxygen use, minimum supplemental oxygen use, maximum respiratory rate, mean respiratory score, and number of times suctioned. They had significantly lower minimum oxygen saturation and caloric intake. Recursive partitioning demonstrated five variables (hours of supplemental oxygen, maximum respiratory rate, minimum supplemental oxygen use, gestation, and caloric intake) to predict short or prolonged LOS with an area under the receiver-operator characteristic curve of 0.89/0.72 in the learning/test trees; sensitivity, 0.85; and specificity, 0.82.

CONCLUSIONS

There are important differences between infants with bronchiolitis having short and prolonged hospital stays, including several clinical markers identifiable on hospital day 2. This model may be a useful prediction tool for targeting early interventions for high-risk infants.

Diabetes and chronic oxidative stress. A perspective based on the possible usefulness of ozone therapy

It is now well established that hyperglycemia, present in both type 1 and type 2 diabetes, causes a variety of biochemical derangements leading to a diffused vascular damage responsible for several pathologic manifestations. Although preclinical and clinical studies have been performed by an unreliable administration route, the correct approach of oxygen-ozonetherapy may break a vicious circle. Messengers, released by a precise interaction ex vivo of the patient's blood with an equivalent calculated dose of ozone (0.42-0.84 mM), react with a variety of cells after blood infusion and restore a number of functions went astray. This paper aims to open a debate on this new therapy for improving the prognosis of diabetes.

[Oxygen-conserving devices: a forgotten resource]

Oxygen-conserving devices include transtracheal catheters, reservoir cannulas, and demand oxygen delivery systems. They are designed to extend the amount of time portable oxygen cylinders will last and correct hypoxemia with a lower flow of oxygen. Transtracheal catheters increase the fraction of inspired oxygen by delivering oxygen directly to the trachea, bypassing the dead space of the oropharynx and improving the efficiency of the upper airway as a reservoir. Reservoir cannulas increase the fraction of inspired oxygen at the beginning of the inspiratory phase. Demand oxygen delivery systems have a valve that is activated during inspiration, meaning that oxygen is only delivered during this stage of the respiratory cycle. Each system has advantages and disadvantages arising from differing design features. Prescription should be based on individual tests in all cases to ensure optimal oxygen delivery during rest, exercise, and sleep.

Advances in the management of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), the fourth leading cause of death, seems to be increasing in worldwide prevalence, and carries with it a significant health and economic burden. Smoking cessation is the only available intervention proven to halt disease progression. The authors discuss the role of the newly approved agent, varenicline, in promotion of smoking cessation. The remainder of presently available therapies treat the symptoms of COPD, but do not impact progression of disease. As the understanding of the pathogenesis of COPD improves, new targets for therapies are emerging. Given the large number of potential targets and the results of recent studies, it seems unlikely that a single new agent will result in a cure. Rather, management of COPD should involve a multi-pronged approach including smoking cessation, bronchodilators, treatment of infection, and eventual targeting of inflammatory pathways and genetic predispositions. In this article, the authors discuss presently available therapies as well as agents under development.

Advances in protocolising management of high risk surgical patients

Despite studies clearly demonstrating significant benefit from increasing oxygen delivery in the peri-operative period in high risk surgical patients, the technique has not been widely accepted. This is due to a variety of reasons, including non-availability of beds, particularly in the pre-operative period, and the requirement of inserting a pulmonary artery catheter. There are now data that suggest that increasing oxygen delivery post-operatively using a nurse-led protocol based on pulse contour analysis leads to a major improvement in outcome with reduction in infection rate and length of hospital stay.

Controversy surrounding the use of home oxygen for premature infants with bronchopulmonary dysplasia

OBJECTIVE

To determine the criteria used in the current practice of neonatology for the initiation of home oxygen therapy in premature infants with bronchopulmonary dysplasia and to compare these criteria with the available literature regarding the use of home oxygen therapy.

STUDY DESIGN

Participants in the December 2000 meeting of the Vermont Oxford Network were surveyed regarding their current use of home oxygen therapy for infants with bronchopulmonary dysplasia.

RESULTS

Surveys were returned by 181 out of 297 participants. Pulse oximetry saturation (SpO2) thresholds for the initiation of home oxygen therapy varied widely from <84% to <98%. The most common threshold was <90% chosen by only 43% of the respondents. Additionally, 22% of the respondents did not initiate therapy until the oxygen saturation in room air was below 88%. Once on oxygen therapy, the target SpO2 also varied widely from >84% to >98%, with only 27% of respondents aiming for an SpO2 of >94%.

CONCLUSIONS

There is a clear lack of consensus among neonatologists regarding the initiation of home oxygen therapy for bronchopulmonary dysplasia. Furthermore, the criteria used for home oxygen therapy varies widely with the majority of neonatologists surveyed using oxygen saturation levels not supported by the literature. We speculate that a significant underutilization of home oxygen therapy exists for infants with bronchopulmonary dysplasia.

Patient ventilation and oxygenation. A new day is dawning

Maintaining an airway and providing adequate ventilation and oxygenation to the patient can be challenging in the prehospital environment. Ventilation and oxygenation are a complex series of interactions between the patient, EMS providers and emergency airway equipment. Routine ventilation techniques carry significant risk of long-term complications. New ventilatory equipment is available to perform this function and provide verification of its effectiveness. This opportunity for improved patient care is available to all EMS providers and sets new standards for delivery of ventilation and oxygenation. The technical methods available to EMS personnel vary considerably and are reviewed in this article.

[The centennial of oxygen-therapy (1902 - 2002)--reassessing its history. Part I: "The long way of oxygen"--from its discovery to its implementation as a rational therapy in anaesthesia and emergency-medicine]

This historical survey in two parts analyses the history of inhalative oxygen therapy and its interactions with the history of anaesthesiology. For this purpose, we will start with illustrating "the long way of oxygen" from its first isolation by Carl Wilhelm Scheele (1772) and Joseph Priestley (1774) to its breakthrough for therapeutic application in the 20th century. We will show that the two main factors delaying the successful implementation of a truly rational oxygen therapy were of technical nature: The complicated and costly production of the gas and insufficient means to apply it continuously and with reliable and sufficient dosages to the patients. Both problems could not be satisfactorily solved until 1902. From this year on, however, the "Linde Process" allowed cheap mass-production of oxygen. Simultaneously, various inventions of modern pressure gas technology allowed to solve the application problems. Here, a special significance is to be awarded to pressure reducing valves. These were first introduced into medical technology by Draeger Inc. (Lübeck/Germany) on a significant scale, proving particularly successful in anaesthesia and rescue-devices (e. g. in the "Roth-Draeger Anaesthesia Apparatus" [1902]). Critically discussing earlier research on the history of oxygen therapy, we therefore propose a historical reassessment, accepting the year 1902 as the internationally decisive "turning point" towards the development of modern oxygen therapy.

Towards new paradigms for the treatment of hypobaric decompression sickness

Altitude induced (hypobaric) decompression sickness (DCS) has long been treated with ground level oxygen and U.S. Navy Treatment Tables 5 and 6. These treatment tables originate from surface excursion diving and, when implemented, require significant resource allocation. Although they are effective treatment regimens, these tables were not developed for treating hypobaric DCS which has an etiology similar to saturation diving DCS. In this review, different treatment options for hypobaric DCS are presented. These options include more aggressive use of ground level oxygen and treatment tables using a maximum pressure of 2 atmospheres (ATA). Specific attention is given to USAF Table VIII, an experimental hypobaric DCS treatment-table, and space suit overpressurization treatment. This paradigm shift for DCS treatment is based on a projected increase in hypobaric DCS treatment from exposure to low pressure during several operational conditions: cruise flight in the next generation aircraft (e.g., F-22); high altitude, unpressurized flight by special operations forces; and the extraordinary amount of extravehicular activity (EVA) required to construct the international space station. Anticipating the need to treat DCS encountered during these and other activities, it is proposed that 2 ATA or less hyperbaric oxygen (HBO) treatment conjoined with new collapsible chamber technology can be used to address these issues in a safe and cost effective fashion.

[New trends in home oxygen therapy (HOT) after the introduction of health insurance coverage in Okinawa and factors contributing to long-term survival]

A total of 179 cases given HOT after introduction of health insurance coverage in 1985 were reported from 12 medical institutes in Okinawa and were compared with 110 cases followed at Okinawa Chubu Hospital during 1976-1985, prior to insurance coverage. The number of patients on HOT have rapidly increased after insurance coverage not only in our institute but also in other institutes in Okinawa and the patients with emphysema formed the largest group. The oxygen enricher is now utilized more than the compressed gas system, accounting for about 70% of all patients compared with the previous figure of 7.3%. Average PaO2 on room air was higher (from 42 Torr to 49 Torr) and the levels of PaO2 maintained by HOT had 2 peaks, one in the 60-65 Torr range and the other in the 75-80 Torr range in patients newly given HOT. The patients with emphysema, who had the worst prognosis in the past, remarkably improved and showed no statistical difference from patients with chronic bronchitis or bronchiectasis in terms of long-term survival. The female patients had better prognosis than males, but the reason is still unclear to us. The absolute volume of FEV1.0 and the presence or absence of cor pulmonale have not affected the long-term survival. A group of the patients with CO2 retention (bronchitic in type) did not benefit from HOT in terms of long-term survival unless their PaO2 levels on room air were below 50 Torr and it was felt that PaO2 levels of 50-59 were too mild in severity for application of HOT.(ABSTRACT TRUNCATED AT 250 WORDS)

New oxygen delivery systems. Gaining patient compliance

The benefits of supplemental oxygen therapy are greatly enhanced if patient compliance is high. Standard nasal cannulae are unattractive by any standard, and patients may remove them to escape stigma or embarrassment. Both transtracheal systems and oxygen systems hidden in eyeglass frames attempt to solve this problem.

Long-term oxygen therapy--state of the art

Long-term oxygen therapy prolongs life in adults with chronic hypoxia caused by chronic bronchitis and emphysema who have cor pulmonale, pulmonary hypertension, and secondary polycythemia ('blue bloaters'). Good results require oxygen therapy for more than 15 hours and preferably 20-24 hours per day. The oxygen concentrator, delivering 1 to 3 l/min of oxygen by nasal prongs, is probably the most cost-effective method of providing this therapy. Dangers of the therapy include fires and burning of patients who smoke, and this is a contraindication to treatment. Excessive CO2 retention during sleep should not result from controlled low-dose oxygen therapy unless the patient also has an obstructive sleep apnea syndrome. Oxygen therapy during sleep may prevent hypoxemic episodes in blue bloaters, and it may thus reverse their pulmonary hypertension, which probably potentiates the risk of right-heart failure and cor pulmonale.

The history of long-term oxygen therapy

Early investigators of oxygen therapy reported an overall clinical improvement in persons with chronic lung disease who received oxygen. Later American and British studies showed that oxygen therapy could decrease pulmonary vascular pressures and red cell mass in some patients with pulmonary hypertension and polycythemia secondary to severe hypoxemia. The British Research Council Study showed that survival rates were significantly higher in patients receiving 15 hours of oxygen than in those receiving no oxygen. The Nocturnal Oxygen Therapy Trial showed that survival rates for persons receiving continuous oxygen therapy has also been shown to improve exercise tolerance and neuropsychiatric function. Further advances in the administration of long-term oxygen therapy and studies in the criteria for its use are needed.

Long term domiciliary oxygen therapy in chronic hypoxic cor pulmonale complicating chronic bronchitis and emphysema. Report of the Medical Research Council Working Party

A controlled trial of long term domiciliary oxygen therapy has been carried out in three centres in the U.K. The 87 patients, all under 70 years of age, who took part had chronic bronchitis or emphysema with irreversible airways obstruction, severe arterial hypoxaemia, carbon dioxide retention, and a history of congestive heart failure. The patients were randomised to oxygen therapy (treated) or no oxygen (controls). Oxygen was given by nasal prongs for at least 15 h daily, usually at 2 1/min. The two groups were well matched, both clinically and in terms of lung function and other laboratory findings. 19 of the 42 oxygen treated patients died in the five years of survival follow-up compared with 30 out of 45 controls: in the 66 men in this trial the survival advantage of oxygen did not emerge until 500 days had elapsed. Survival for the 12 female controls was surprisingly poor, 8 of them being dead at 3 years. Mortality was not easy to predict, though a summation of arterial carbon dioxide tension and red cell mass was helpful. Neither time spent in hospital because of exacerbations of respiratory failure nor work attendance were affected by oxygen therapy, but these patients were very ill at the start of the trial and many had already retired on grounds of age or ill-health. Physiological measurements suggested that oxygen did not slow the progress of respiratory failure in those who died early. However, in longer term survivors on oxygen, arterial oxygenation did seem to stop deterioration.