Recent technical advances in portable oxygen delivery systems]

According to a Japanese national survey (June 30, 1990), the number of patients receiving home oxygen therapy (HOT) has been greater than 18,000 since March 1985, when HOT was first covered by health insurance. The oxygen concentrator, especially the molecular sieve type, is the most common method of delivery (more than 90%). In April 1988, the portable oxygen cylinder was acknowledged by health insurance, and the liquid oxygen supply system in April 1990. Three types of portable oxygen delivery systems are available; oxygen cyclinder, liquid oxygen system, and oxygen concentrator (membrane type), of which the oxygen cylinder is most commonly used. In our hospital, portable oxygen supply systems were used in 80% of 168 HOT cases in 1990, and the use of 400 L aluminum oxygen cylinders at a flow rate of 1-2 L/min has been most popular. There is an strong desire from patients for lighter portable oxygen supply system of longer duration. In 19 patients with chronic respiratory failure, we evaluated a newly designed demand oxygen delivery system (DODS), which weighs 2.4 kg including the DOD device (TER-20 Teijin), 1.1 L oxygen cylinder made of ultressor, nasal cannula, and carrier. Arterial blood gases at rest (room air) were PaO2 61.9 +/- 6.3 torr, PaCO2 63.8 +/- 9.4 torr and pH 7.40 +/- 0.04. A crossover trial was performed under three conditions; breathing room air with no weight, and pulse oxygen flow and continuous oxygen flow each carrying 2.4 kg of weight. Both 6 minute walking (E1) and walking on a slow speed treadmill (E2) were studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute oxygen therapy does not improve cognitive and driving performance in hypoxaemic COPD

Background and objective: Cognitive and neuropsychological function may be adversely affected by low blood oxygen levels and this has been previously demonstrated in hypoxaemic COPD. The aim of this study was to assess whether supplemental oxygen therapy while driving a motor vehicle is justified in hypoxaemic COPD. We therefore used computer-based driving simulation to investigate whether acute intranasal oxygen therapy improves the cognitive and driving performance of such patients. Methods: Thirty hypoxaemic COPD subjects with a current driving licence performed a 20-min computer-based driving simulation task and a 10-min psychomotor vigilance task (PVT) at baseline, and while breathing intranasal oxygen or intranasal air in a randomized, double-blind, cross-over protocol. Results: The mean (SD) age of the subjects was 72 years (8) and their mean driving experience was 50 years (10). Mean FEV₁ was 41% (18) of predicted and PaO₂ was 50.5 mm Hg (4.7) on air and 70.7 mm Hg (9.1) on oxygen. There were no statistically significant differences in any measure of driving performance or in reaction time measurements while breathing oxygen compared with air. Conclusions: Acute oxygen therapy does not improve simulated driving performance or neurocognitive function as assessed by PVT in patients with hypoxaemic COPD. These data do not support the recommendation that oxygen should be used by this patient group while driving.     

Questionnaire survey on the continuity of home oxygen therapy after a disaster with power outages

BackgroundAfter the Great East Japan Earthquake, oxygen-dependent patients in areas experiencing power outages could not continue home oxygen therapy (HOT) without oxygen cylinders. The purpose of this study was to examine use of oxygen cylinders in areas experiencing power outages and the effects of HOT interruption on patients' health.MethodsQuestionnaires were mailed to 1106 oxygen-dependent patients and HOT-prescribing physicians in Akita, near the disaster-stricken area. We investigated patients' actions when unable to use an oxygen concentrator and classified the patients based on oxygen cylinder use. Patients who experienced an interruption of or reduction in oxygen flow rate by their own judgment were assigned to the “interruption” and “reduction” groups, respectively; those who maintained their usual flow rate were assigned to the “continuation” group. Differences were tested using analysis of variance and the χ² tests.ResultsIn total, 599 patients responded to the questionnaire. Oxygen cylinders were supplied to 574 patients (95.8%) before their oxygen cylinders were depleted. Comparison of the continuation (n=356), reduction (n=64), and interruption (n=154) groups showed significant differences in family structure (p=0.004), underlying disease (p=0.014), oxygen flow rate (p<0.001), situation regarding use (p<0.001), knowledge of HOT (p<0.001), and anxiety about oxygen supply (p<0.001). There were no differences in changes in physical condition.ConclusionsMost patients could receive oxygen cylinders after the disaster. Some patients discontinued their usual oxygen therapy, but their overall health status was not affected.     

Immunopharmacological effect of a Japanese herbal medicine (Hochu-ekki-to) on the elderly

Hochu-ekki-to (HOT) has long been used for treatment of the elderly complaining of severe weakness. In this study, we examined its immunopharmacological effect on 16 elderly patients, aged 76.5 years on average and complaining of general fatigue. They were administered orally 7.5 g of HOT every day for at least 120 days (4 months), which provided them with a noticeable improvement of their physical condition. From the immunological point of view, during the observation period, the total number of circulating leukocytes remained unchanged, as well as the ratios between CD3⁺T- and CD20⁺B-cells and between CD4⁺T- and CD8⁺T-cells. However, as verified on day 30 as well as on day 120 after the administration of HOT, the activity of NK against K562 target cells was significantly enhanced. Also, on days 30 and 120, there was a significant increase in serum IFN-γ level which is thought to be associated with NK activity. From these results, it may be concluded that the oral administration of HOT to the elderly may help them ameliorate, at least partially, their immunological capacity as well as their physical condition.     

Home oxygen therapy for terminal lung cancer cases]

Home oxygen therapy (HOT) was introduced as part of the terminal care of 52 lung cancer patients attending our hospital from 1997 to 2000, all of whom subsequently died from their illnesses. We administered a questionnaire about HOT to their bereaved family members. The results confirmed that many of those interviewed thought that HOT improved their quality of life, but probably made the patients more aware of the progression of their disease. As the incidence of lung cancer has been increasing, lung cancer patients have begun to form an increasing proportion of patients receiving HOT in recent years. In addition, the number of patients with a PaO2 of > or = 60 torr at rest at the start of HOT has been increasing. It may be necessary when dealing with terminal lung cancer patients, in whom PaO2 can decrease rapidly over a relatively short period of time, to explore indication criteria for HOT different from those conventionally employed.     

De-escalation of Oxygen Therapy and Medication in Patients With Chronic Thromboembolic Pulmonary Hypertension After Balloon Pulmonary Angioplasty

BackgroundThere is no consensus on the adjustment of home oxygen therapy (HOT) and pulmonary hypertension (PH)-specific medications after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to examine the status of de-escalation and discontinuation of HOT and PH-specific medications post-BPA and clarify its effect on hemodynamics, biomarkers, and long-term outcomes.MethodsFrom November 2012 to May 2018, 135 consecutive patients with CTEPH who underwent BPA at a single university hospital were enrolled (age, 63.5 ± 13.5 years; World Health Organization functional class (WHO-FC) II, III, IV; 34, 92, 9).ResultsThe mean pulmonary arterial pressure decreased from 37.7 ± 11.3 to 20.4 ± 5.1 mm Hg 1 year post-BPA (P < 0.01). The proportion of patients who required HOT and combination medical therapy (≥ 2 PH-specific medications) decreased 1 year post-BPA (from 58.5% to 7.4% and from 40.0% to 10.4%, respectively). Baseline factors influencing the requirement of HOT and combination medical therapy post-BPA were almost identical (ie, lower exercise capacity and pulmonary diffusion capacity and worse hemodynamics). Regardless of their discontinuation, the improved hemodynamics, functional capacity (WHO-FC), and biomarkers (B-type natriuretic peptide and high-sensitivity troponin T) were almost maintained, and no adverse 1-year clinical outcomes (all-cause death and PH-related hospitalization) were observed.ConclusionsMost patients with CTEPH discontinued HOT and PH-specific combination medical therapy post-BPA, which was not associated with the deterioration of hemodynamics, functional capacity, or biomarkers. No long-term adverse outcomes were observed.     

Airline policy for passengers requiring supplemental in-flight oxygen

Background and objective:   The aim of this study was to investigate the current Australian/New Zealand airline policy on supplemental in-flight oxygen for passengers with lung disease.
Methods:   Fifty-four commercial airlines servicing international routes were surveyed. Information was gathered from airline call centres and web sites. The survey documented individual airline policy on in-flight oxygen delivery, approval schemes, equipment and cost.
Results:   Of the 54 airlines contacted, 43 (81%) were able to support passengers requiring in-flight oxygen. The majority (88%) of airlines provided a cylinder for passengers to use. Airline policy for calculating the cost of in-flight oxygen differed considerably between carriers. Six (14%) airlines supplied oxygen to passengers free of charge; however, three of these airlines charged for an extra seat. Fifteen airlines (35%) charged on the basis of oxygen supplied, that is, per cylinder. Fourteen airlines (33%) had a flat rate charge per sector.
Conclusions:   This study confirmed that most airlines can accommodate passengers requiring supplemental oxygen. However, the findings highlight inconsistencies in airline policies and substantial cost differences for supplemental in-flight oxygen. We advocate an industry standardization of policy and cost of in-flight oxygen.     

Effects of nocturnal oxygen therapy on outcome measures in patients with chronic heart failure and cheyne-stokes respiration.

BACKGROUND: The effects of nasal oxygen (O(2)) supply at night using conventional home oxygen therapy (HOT) equipment on quality of life (QOL) and sleep-disordered breathing (SDB) were evaluated in patients with congestive heart failure (CHF). Nasal nocturnal O(2) therapy not only stabilizes SDB but also reduces sympathetic activity, and improves exercise capacity in patients with CHF. However, the effects of oxygen on the cardiac function and QOL of heart failure patients have not been fully elucidated. METHODS AND RESULTS: Fifty-six patients with CHF (New York Heart Association class II - III, left ventricular ejection fraction (LVEF) 相似文献   

Ambulatory monitoring of arterial oxygen saturation

We have developed a method of recording oxygen saturation over time using ambulatory equipment. A pulse oximeter was modified to be powered by battery, and values for oxygen saturation were recorded by an analog recorder. The unit is compact and functions for 30 hours between battery changes. The mean difference between oxygen saturation reported by the pulse oximeter and an IL 282 CO-oximeter was -1.12 percent, with a range of difference +/- 2.75 percent, indicating 95 percent confidence limits 5.5 percent either side of the mean. Continuous ambulatory recordings were obtained in 16 male subjects; six were healthy nonsnorers, five were healthy snorers, and five had sleep apnea. Of the average recording time, 19 +/- 5 hours, records contained 89 +/- 7 percent usable data. We conclude that ambulatory pulse oximetry is a feasible means of unsupervised long-term monitoring of oxygenation during daily activities.     

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)     

Six years follow-up of an implanted SvO(2) sensor in the right ventricle

INTRODUCTION: Mixed venous oxygen saturation (SvO(2)) is a standard invasive measure used in the management of congestive heart failure patients. The reliability of a long-term SvO(2) sensor remains unproven. METHODS: Nine patients (NYHA Class I/II, n=2/7) were implanted with a dual chamber pacemaker modified to utilize a right ventricular SvO(2) lead (Medtronic Inc., Models 8007/4327A IPG/Lead). Invasive studies compared sensor SvO(2) to reference (Optical Swan-Ganz catheter) at 0, 3 and 9 months. Symptom limited tests (Bike(max)) with metabolic assessment and arterial oxygen saturation measurements performed 1-7 days, 3.5 and 9.5 months post-implant allowed for cardiac output calculations. Long-term sensor performance was confirmed by submaximal tests, Bike(subm) in years 1-3, and Walk(in-place) every 6 months for the duration of follow-up. RESULTS: Sensor SvO(2) readings were stable over time when compared to the Swan-Ganz Catheter. Non-invasive CO measured during Bike(max) was in normal ranges for this patient population, 3.7+/-0.9 l/min at rest and 8.4+/-2.2 l/min at peak-exercise. Resting SvO(2) values from Bike(subm) and Walk(in-place) did not change significantly over time (P>0.1 vs. 1 year) and neither did the change from rest to peak exercise during Bike(subm) (P>0.05 vs. 1 year) or Walk(in-place) (P>0.05 vs. 4 year). CONCLUSION: While limited in size, this small pilot study suggests that long-term monitoring of SvO(2) by implanted devices may be feasible. The clinical value remains to be proven in future studies.     

Tuberculosis sequelae: home care of patients

Home oxygen therapy (HOT) is important in the management of patients with chronic respiratory failure. I evaluated 159 HOT cases in our hospital during the period of 1988-1989. According to the national annual survey during the same period, HOT cases with tuberculosis sequelae were 46% of total national sanitorial HOT cases and 26-30% of all Japanese ones. Oxygen enrichers, especially molecular sieve type, became major methods of oxygen delivery (almost 90%) in both cases mentioned above. In our study, however, there were more patients with tuberculosis sequelae (66%), and more oxygen cylinder users (40%). Portable oxygen supply was higher in our HOT cases, especially in patients with tuberculosis sequelae or chronic pulmonary emphysema, and in users of oxygen cylinders or liquid oxygen. By questionnaire, we confirmed the earnest desire by the patients for the lighter and long lasting portable oxygen supply system.     

Prognostic significance of serum uric acid in patients with chronic obstructive pulmonary disease receiving home oxygen therapy]

Home oxygen therapy (HOT) not only prolongs life expectancy but also improves quality of life. Serum uric acid (UA), the final product of purine catabolism, has been shown to be increased in the hypoxic state. To elucidate the prognostic significance of serum UA in patients with chronic obstructive pulmonary disease (COPD) receiving HOT, we assessed the ratio between the serum concentration of UA and creatinine (Cr) in 91 outpatients with COPD. During a mean follow-up period of 31 months, 24 patients died of acute exacerbation of COPD. The delta UA/Cr ratio was calculated as the percent changes in serum UA/Cr during HOT. delta UA/Cr was increased in non-survivors, but not in survivors, and was negatively correlated with the nadir of oxyhemoglobin saturation (r = -0.32, p < 0.01). Of the clinical and laboratory variables, only the delta UA/Cr ratio was found to be independently related to mortality by a multivariate Cox proportional-hazards analysis. The Kaplan-Meier survival curves divided into values below and above the median value (9.7%) of this ratio demonstrated that mortality was significantly higher among patients with high values than among those with low values (log-rank test: p < 0.05). We conclude that the delta UA/Cr ratio appears to be a reliable marker of prognosis, and may be useful for the long-term follow-up of outpatients with COPD receiving HOT.     

Long-term care insurance eligibility in Japan for patients having home oxygen therapy]

In Japan, long-term care insurance (LTCI) for the elderly has been available since April 2000. Eligibility levels for LTCI for patients with home oxygen therapy (HOT) was investigated for two periods during a 20-month interval between April 2000 and December 2001. During these periods, we hosted a seminar on respiratory care, taking the form of a special report on the daily life of HOT patients. This report was submitted to an expert committee in order to inform the members of the committee about the characteristics of HOT patients. Of 76 HOT patients who had utilized visiting-nurse services, 58 applied for an assessment for LTCI eligibility. The levels determined were less than those expected by the patients' doctors (Categories: Not fulfilling the criteria, seven cases; Rejected, 13 cases; Assistance-required, six cases; Care-required, level 1, 14 cases; Care-required, level 2, 10 cases; Care-required, level 3, three cases; Care-required, level 4, three cases; and Care-required, level 5, two cases). As many as six of the 27 patients who used home mechanical ventilation were rejected. There were also patients who were forced to stop the care services that they had been receiving. Forty patients, including eight who applied for a re-assessment, were finally assigned to a Care-required category. The home-help service was the most frequently utilized (35.0%). Day services, short stay, and the visiting-bathing service, which are commonly used for patients with cerebral apoplexy sequela, were not needed nearly as much (5.0%, 2.5%, 2.5%, respectively). The eligibility levels at the second point of evaluation were higher than those at the first point in 37.5% of the patients, and equal in 58.3%. In the 39 new-applicant patients at the second point of evaluation, the ratio of Care-required patients was significantly increased (62.7% to 72.2%, p < 0.05). The eligibility level is primarily decided by computer using a score derived from a form that contains 73 questions about the physical condition of the applicant. However, this information is inadequate for a precise assessment of the impairment of the HOT patients. The final decision on a patient is made by an expert committee, based on both the primary result and the report of the doctor in charge of that patient. It may be effective to inform the members involved in the final decision about the characteristics or special needs resulting from the disease that necessitates HOT. However, we believe that it may be more important to find a way to increase the validity of the primary judging. We would argue that a method for proper assessment of HOT patients should be designed.     

Tucaresol increases oxygen affinity and reduces haemolysis in subjects with sickle cell anaemia

The primary pathophysiological event in sickling is the intracellular polymerization of deoxygenated haemoglobin S. Tucaresol (589C80;4[2-formyl-3-hydroxy-phenoxymethyl] benzoic acid), a substituted benzaldehyde, was designed to interact with haemoglobin to increase oxygen affinity and has been shown to inhibit sickling in vitro . We administered tucaresol to sickle cell patients in the steady state to examine the anti-sickling effect in vivo. Oral doses of tucaresol or placebo were given to nine stable sickle cell patients (aged 17–39 years; tucaresol, six; placebo, three) for 10 d. The first two patients on tucaresol were scheduled to receive a loading dose of 800 mg or 1200 mg (depending on bodyweight) for the first 4 d, followed by maintenance doses of 200 or 300 mg for the next 6 d. Due to concerns over the sharp rise in haematocrit in one patient, subsequent cohorts received 300 mg tucaresol daily throughout the dosing period. The oxygen affinity of haemoglobin S was increased in all patients receiving tucaresol, with between 10% and 24% of the haemoglobin modified, dependent on dose. In all patients on tucaresol, haemolysis was reduced with rises in haemoglobin of 0.9–3.7 g/dl (mean 2.2 g/dl), falls in lactate dehydrogenase of 16–52%, and a halving of the irreversibly sickled cell counts. These effects were apparent within a few days and persisted for 1–2 weeks following discontinuation of the drug. Three of the six patients on tucaresol developed fever and cervical lymphadenopathy, with onset between days 7 and 11 from start of drug. Further evaluation of the tolerability and efficacy of tucaresol in sickle cell patients is necessary.     

Randomised trial of ambulatory oxygen in oxygen-dependent COPD.

Long-term oxygen therapy may limit a patient's ability to remain active and may be detrimental to the rehabilitation process. This study aimed to determine the effect of ambulatory oxygen on quality of life and exercise capacity in patients with chronic obstructive pulmonary disease fulfilling the usual criteria of long-term oxygen therapy. In a 1-yr, randomised, three-period, crossover trial, 24 patients (mean age 68 yrs; mean arterial partial pressure of oxygen at rest 7.1 kPa (53 mmHg)) were allocated to one of the six possible sequences generated by three interventions: 1) standard therapy (home oxygen therapy with an oxygen concentrator only); 2) standard therapy plus as-needed ambulatory oxygen; and 3) standard therapy plus ambulatory compressed air. The comparison of ambulatory oxygen versus ambulatory compressed air was double blind. The main outcomes were quality of life (Chronic Respiratory Questionnaire), exercise tolerance (6-min walk test) and daily duration of exposure to oxygen therapy. The trial was stopped prematurely after an interim analysis. On average, the patients used few ambulatory cylinders (7.5 oxygen cylinders versus 7.4 compressed air cylinders over a 3-month study period). Ambulatory oxygen had no effect on any of the outcomes. In conclusion, the current results do not support the widespread provision of ambulatory oxygen to patients with oxygen-dependent chronic obstructive pulmonary disease.     

Comparison of an oxygen concentrator and wall oxygen in the assessment of patients undergoing long term oxygen therapy assessment

Long term oxygen therapy (LTOT) is a recognised management option for hypoxaemic patients with chronic respiratory disease. Formal assessment is required which is usually conducted in the hospital and performed on piped oxygen to ensure correction of the hypoxaemia. However, an oxygen concentrator is the standard oxygen source for the patient at home who requires LTOT. The oxygen concentration delivered is lower from a concentrator than piped oxygen. Here, we present a study of ten hypoxaemic patients using both delivery sources in a cross-over design. The partial pressure of oxygen was lower in patients when receiving oxygen from a concentrator, p < 0.05. This encourages the Clinician to consider formal assessments on an oxygen concentrator in order to ensure that the hypoxaemia will be corrected when they are prescribed a concentrator for home use.     

Prospective evaluation of haemoglobin oxygen saturation at rest and after exercise in paediatric sickle cell disease patients

Low steady state haemoglobin oxygen saturation in patients with sickle cell anaemia has been associated with the degree of anaemia and haemolysis. How much pulmonary dysfunction contributes to low saturation is not clear. In a prospective study of children and adolescents with sickle cell disease aged 3–20 years at steady state and matched controls, 52% of 391 patients versus 24% of 63 controls had steady state oxygen saturation <99% ( P  < 0·0001), 9% of patients versus no controls had saturation <95% ( P  = 0·008) and 8% of patients versus no controls had exercise-induced reduction in saturation ≥3%. Decreasing haemoglobin concentration ( P  ≤ 0·001) and increasing haemolysis ( P  ≤ 0·003) but not pulmonary function tests were independent predictors of both lower steady-state saturation and exercise-induced reduction in saturation. Neither history of stroke nor history of acute chest syndrome was significantly associated with lower steady-state oxygen saturation or exercise-induced reduction in saturation. Tricuspid regurgitation velocity was higher in patients with lower steady state haemoglobin oxygen saturation ( P  = 0·003) and with greater decline in oxygen saturation during the six-minute walk ( P  = 0·022). In conclusion, lower haemoglobin oxygen saturation is independently associated with increasing degrees of anaemia and haemolysis but not pulmonary function abnormalities among children and adolescents with sickle cell disease.     

Pilot study of oxygen transport rate of banked red blood cells

Background and Objectives  Dynamic oximetry provides a new way to assess the effect of blood storage on the oxygen transport rate (OTR).
Materials and Methods  In dynamic oximetry, the rate at which oxyhemoglobin becomes deoxyhemoglobin is measured optically, thereby, indirectly measuring the rate at which oxygen leaves the red blood cell (RBC) making it available for transfer to tissues. Extending the physiologic diffusion time in an in vitro apparatus, consisting of a diffusion system and gas exchanger capable of controlling the surface area and the time of exposure for oxygenation and deoxygenation, makes OTR measurement feasible. Eight normal blood donor units, collected in adenine, dextrose, sorbitol, sodium chloride and mannitol , were stored for 8 weeks under standard conditions and serially sampled for OTR.
Results  We report that the OTR at the time of blood bank donation appears to be singular for each donor, that the interdonor differences are maintained over time, and that the individual OTR increased 1·72-fold (95% CI 1·51, 1·95) over 8 weeks, adjusting for sex, age and plasma cholesterol level.
Conclusion  Oxygen transport rate increases during storage; blood units with similar haemoglobin content may have significant differences in OTR. Studies examining blood parameters at the time of donation and blood storage on patient outcomes should consider measuring OTR, as it may contribute to differences in observed efficacy of tissue oxygenation.