Prescription and usage of long-term oxygen therapy in patients with chronic obstructive pulmonary disease in The Netherlands.

Long-term oxygen therapy (LTOT) has been shown to improve survival in hypoxaemic patients with chronic obstructive pulmonary disease (COPD). This has resulted in recommending the prescription of oxygen for at least 15 h day-1 in most European countries. In order to examine the prescription and usage of LTOT and to assess the adherence to international recommendations for its prescription, a survey was set up in a random sample of clients of the largest oxygen company in the Netherlands. After patients had been visited for an interview, additional postal surveys were sent to the physician who had prescribed LTOT and to the oxygen company. For 175 COPD patients the mean oxygen prescription and mean oxygen usage were 15.6 +/- 5.8 and 14.1 +/- 6.8 h day-1, respectively. In 62 patients (35%) oxygen was prescribed < 15 h day-1, more often by non-chest physicians than by chest physicians (P < 0.0001), and 91 patients (52%) used oxygen < 15 h day-1. Of 113 patients with a prescription > or = 15 h day-1, 39 (35%) used oxygen < 15 h day-1 and 74 for > or = 15 h day-1. The latter were prescribed oxygen for more h day-1, had been longer on LTOT, had a higher resting flow rate, were prescribed a concentrator, employed portable cylinders and used oxygen in public significantly more often than the former. We conclude that in a selected group of LTOT patients with COPD both oxygen prescription and usage were often inadequate, particularly if LTOT was prescribed by non-chest physicians.

Accuracy of oxygen delivery by liquid oxygen canisters.

The oxygen flow rate delivered by liquid oxygen canisters may be less than intended, owing to inaccuracies of the set flow rates and/or as a result of the outflow resistance caused by the humidifier, oxygen tubing, delivery or conserving device. The aim of this study was to investigate the accuracy of oxygen delivery by liquid oxygen canisters at different flow rates and levels of outflow resistance. Four stationary and 18 portable liquid oxygen canisters from three manufacturers were tested. All flows were measured using a Timemeter RT 200 Calibration Analyser. An adjustable obstruction was used to calculate the effect of the outflow resistance on the delivered flow rate. The measured and set flow rates of both stationary and portable canisters were strongly correlated. Expressed as a percentage of the set flow rate, the measured flow rate of the canisters varied from 36-128%, with the lowest values at flow rates <1 L x min(-1). Sixty-two (26%) of the measured flow rates differed > or =10% from the set flow rate. A difference of 0.5-1.0 L x min(-1) occurred in 16 (7%) of the measurements, but only at set flow rates >2 L x min(-1). Irrespective of the set flow rate, the measured flow rate was hardly affected by the outflow resistance. We conclude that the accuracy of oxygen delivery by liquid oxygen canisters depends on the inaccuracy of the set flow rates rather than on the outflow resistance, even at high flow rates. Although the differences between the measured and set flow rates were mostly small, they may have clinical significance, particularly in patients with chronic obstructive pulmonary disease. To prevent inaccuracy, monthly checks of the canisters by the oxygen provider at the patient's home are more important than yearly maintenance.

Characteristics and complaints of patients prescribed long-term oxygen therapy in The Netherlands.

In patients prescribed long-term oxygen therapy (LTOT), compliance is often poor. Both patient- and treatment-related factors seem to be involved. As a base for improvements in LTOT, the characteristics and complaints of LTOT patients were investigated. A survey was set up in a random sample of clients of the largest oxygen company in the Netherlands. Patients were selected if they were > or = 18 years old, had a phone and if they had had oxygen equipment for > or = 6 months. All patients were visited at home by a medical student. Data are presented for a total of 528 patients (response rate 62%). The typical LTOT patient was a 70-year-old male with chronic obstructive pulmonary disease (COPD), who had had oxygen equipment for 3.5 years and who used oxygen cylinders and nasal cannulae for 13 h day-1. Twenty percent of the patients still smoked. Although LTOT was prescribed in 80% of the patients by a chest physician, prescription was often inadequate. Only 33% of the patients were informed adequately about the therapy. Twenty percent of the patients used oxygen for fewer hours per day than prescribed. Non-compliant patients were mainly men (P = 0.006) and more often ashamed of their therapy (P = 0.023) than compliant patients. The blood oxygen level was monitored regularly in 73% of the patients. Most complaints concerned the oxygen equipment, especially the concentrator. The single most important complaint had to do with restricted autonomy. Only 19% of the patients had no complaints at all. It is concluded that LTOT should be improved with regard to the education, motivation and monitoring of patients. The prescribing physician needs to be included in an education programme. Given the numerous problems these patients experience, LTOT should be improved in particular with regard to equipment convenience.

Transtracheal oxygen therapy: an effective and safe alternative to nasal oxygen administration.

Transtracheal oxygen therapy (TTOT) improves the efficiency of oxygen delivery and overcomes the discomfort associated with nasal oxygen delivery in patients on long-term oxygen therapy (LTOT). In addition, TTOT improves compliance and quality of life, and may reduce morbidity. Experience with TTOT in Europe is, however, scarce and the safety of TTOT has not yet been completely determined. These were reasons for testing the acceptance, efficacy and safety of TTOT. Patients were selected on the basis of the accepted indications and contraindications for TTOT. In 75 patients (48 males and 27 females) the mean follow-up time was 16 (range 0.5-51.5) months. Compared to nasal cannulae, TTOT caused a reduction in the oxygen flow rate of 47 (33-60)% at rest and a significant increase in the number of hours that oxygen was used. All patients on TTOT used oxygen for at least 20 h x day(-1). Most patients saw the procedure as a minor intervention. It was usually performed on an out-patient basis. In 34 patients, 51 mainly minor complications were seen, and most of these occurred in the first 10 patients. After precautions had been taken, complications occurred less frequently. No patient needed to be hospitalized because of a complication. TTOT had to be stopped in two patients; nevertheless, all patients preferred TTOT to the nasal cannulae. We conclude that transtracheal oxygen therapy is an effective and safe alternative to nasal oxygen administration, provided that it is restricted to a well-defined group of patients and applied by a motivated and experienced group of physicians.

[Favorable results of nocturnal nasal positive-pressure ventilation in 64 patients with neuromuscular disorders; 5-year experience]. / Gunstige effecten van nachtelijke nasale positieve-drukbeademing bij 64 patiënten met neuromusculaire aandoeningen; 5 jaar ervaring.

OBJECTIVE: Evaluation of the effectiveness of chronic nightly mechanical ventilation through a nasal mask system in patients with neuromuscular diseases or patients with thorax malformations or COPD. SETTING: Centre for Home Mechanical Ventilation, University Hospital Utrecht. DESIGN: Retrospective study. METHOD: During the period June 1988-May 1993, 64 patients (11-69 years old) were treated with nasal mask ventilation during the night: 37 men (most of whom had Duchenne's disease (18) and 27 women (most of whom had (post-polio) kyphoscoliosis (n = 13). The effects on arterial blood gases were analysed. Complications during use of the nasal mask systems were recorded. RESULTS: The duration of the nasal mask ventilation was 2 to 56 months. Arterial PCO2 and PO2 improved during the night as well as by day during spontaneous respiration. The most common problems were necrosis of the skin of the bridge of the nose, leakage of air through the mouth or insufflation of air into the stomach. After the start of the mechanical ventilation quality of life improved considerably. CONCLUSION: Nasal ventilation at night is sufficient and simple. The installation of a tracheostoma can be postponed or avoided with this non-invasive kind of ventilation.

Long-term oxygen therapy.

This review discusses the different aspects of long-term oxygen therapy (LTOT). In selected patients with chronic hypoxaemia, LTOT may increase the life-span and quality of life. Since identification of these patients is both important and difficult, the indications for LTOT are discussed. Next, the appropriate time at which LTOT should be initiated is discussed in the section on the physiological criteria. Even in patients who qualify for LTOT, the effectiveness of this therapy may vary. Because they are important in this context, the prescription guidelines are considered. Finally, possible ways of increasing the efficiency of LTOT are reviewed in the sections on home oxygen systems, oxygen-conserving methods and the organization of LTOT in the Netherlands.

Therapeutic problems in cyanide poisoning.

In three patients with severe acute cyanide poisoning, a cyanosis was observed instead of the bright pink skin coloration often mentioned as a sign in textbooks. Treatment of cardiopulmonary insufficiency is as essential as antidotal therapy and the use of sodium nitrite and 4-DMAP is not without risk as, in practice, the methemoglobin-level induced is difficult to control.

Reduced cardiotoxicity and nephrotoxicity with preservation of antitumor activity of doxorubicin entrapped in stable liposomes in the LOU/M Wsl rat.

LOU M/Wsl rats inoculated s.c. with 10(4) immunoglobulin immunocytoma cells have a palpable tumor at Day 17. Doxorubicin (DXR) has been entrapped in negatively charged liposomes (lip- DXR) composed of egg phosphatidylcholine, cholesterol, and phosphatidylserine and in positively charged liposomes (lip+ DXR) composed of phosphatidylcholine, cholesterol, and stearylamine. DXR, lip- DXR, and lip+ DXR were administered i.v. (0, 0.25, 0.5, 1.0, and 2.0 mg/kg) at Day 17 for 5 consecutive days and then weekly. Control animals showed progressive tumor growth leading to death 27 days after inoculation. Antitumor activity for all three preparations was dose dependent. DXR and lip- DXR showed the same antitumor activity; lip+ DXR had less antitumor activity. The overall survival of tumor-bearing animals treated with 2.0-mg/kg lip- DXR was significantly prolonged (p less than 0.05) in comparison to the animals treated with 2.0-mg/kg free DXR. Grade III cardiomyopathy was observed 47 days after treatment with free DXR; treatment with lip- DXR resulted in Grade I cardiomyopathy. In animals treated with 1.0-mg/kg and 2.0-mg/kg free DXR urinary albumin concentrations of 10 g/liter were observed. Treatment with 1.0-mg/kg lip- DXR and 1.0-mg/kg lip+ DXR resulted in urinary albumin concentration of less than 3.0 and less than 1.0 g/liter, respectively. Free DXR, 1.0 mg/kg, resulted in a decline of serum albumin concentration from 27.8 +/- 3.2 g/liter to 9.6 +/- 4.2 g/liter. No such decline was observed after treatment with lip- DXR and lip+ DXR. Treatment with a 1.0-mg/kg dose of free DXR resulted in severe glomerular and tubular lesions which were not found after treatment with 1.0-mg/kg lip- DXR and 1.0 mg/kg lip+ DXR. Administration of lip- DXR resulted in lower DXR levels in cardiac and renal tissue compared to administration of free DXR. After administration of lip+ DXR, very low tissue and tumor DXR levels were found. In conclusion, treatment with lip- DXR or lip+ DXR resulted in a prolonged survival, less albuminuria, and higher serum albumin levels. Also, fewer lesions in heart and kidney were found, correlating with lower DXR levels in these organs. Only lip- DXR had the same antitumor effect as free DXR.