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.

A longitudinal study of maternal hemodynamics during normal pregnancy.

OBJECTIVE: To investigate the maternal hemodynamic changes that occur during normal pregnancy. METHODS: Serial hemodynamic investigations were performed throughout normal pregnancy by thoracic electrical bioimpedance monitoring in 50 healthy women. Analysis of variance with repeated measurements was used to evaluate the time course of a number of hemodynamic indies. RESULTS: The mean heart rate (+/- standard error [SE]) increased gradually from 87 +/- 2 beats per minute at 10-18 weeks' gestation to 92 +/- 1 beats per minute at 34-42 weeks' gestation. Mean arterial pressure decreased significantly after 14 weeks' gestation and increased significantly after 29 weeks' gestation. During the third trimester, mean cardiac output and mean stroke volume decreased, and mean systemic vascular resistance increased significantly. The course of cardiac output during the third trimester was not uniform in all women; it increased in nine and decreased in 41 women. A significantly higher mean cardiac output was found in nulliparous women compared with multiparous women (mean difference +/- SE 0.76 +/- 0.33 L/minute). The mean (+/- SE) cardiac output increased significantly from 6 (5.49 +/- 0.16 L/minute) to 12 weeks' postpartum (5.91 +/- 0.19 L/minute). CONCLUSION: Mean cardiac output and mean stroke volume decreased in late pregnancy. A significant difference in mean cardiac output was observed between nulliparous and multiparous women. Cardiac output usually, but not invariably, declined during the third trimester.

Single-dose prophylaxis with broad-spectrum penicillins (piperacillin and mezlocillin) in gynecologic oncological surgery, with observation on serum and tissue concentrations.

Serum, fat and pelvic tissue levels of piperacillin or mezlocillin (patients randomly selected to receive one of both) were measured during surgery of 48 patients (mean age 55 years) with gynecologic cancer and related to the minimal inhibitory concentrations (MIC). Only during the first 3 hours the fat and pelvic tissue levels of these antibiotics were above the MIC levels (3 to 5 mg/l), while the serum reached marginal levels after 4 to 5 hours. Excessive blood loss (more than 1.500 ml) decreases the serum and fat levels; however, during the first 3 hours not below the MIC values. Single-dose prophylaxis with both antibiotics appeared fully effective in debulking surgery, total abdominal hysterectomy and radical hysterectomy. However, out of a group of 12 patients who underwent radical vulvectomy, 8 patients had postoperative infections.

What is the best predictor of the severity of ABO-haemolytic disease of the newborn?

In 80 newborn infants ABO-incompatible with their mothers, the lysis-inducing effect of the maternal IgG anti-A or anti-B antibodies in an antibody-dependent cell-mediated cytotoxicity (ADCC) assay and the antigen density of A or B antigens on the red cells of the children were measured. On the basis of the results, the children were divided into two groups--24 children in whom increased haemolysis was to be expected, and 56 children in whom it was not. Signs of haemolysis and serological features of ABO haemolytic disease of the newborn (ABO-HDN) were compared in these two groups and a control group of 120 ABO-compatible infants. The effect of the maternal antibodies in the ADCC assay, the titres of maternal IgG anti-A or anti-B antibodies, the results of the direct antiglobulin test on the red cells in the cord blood, and the titre of IgG anti-A or anti-B antibodies in the serum of the infants were compared for their ability to predict the severity of ABO-HDN. This was also done for the combination of the ADCC assay results plus the A or B antigen density and the direct antiglobulin test plus the titre of maternal IgG anti-A or anti-B antibodies. The ADCC assay with maternal serum was the most sensitive assay to predict ABO-HDN, and the combination of the ADCC assay with A or B antigen density determination the most specific test.

The alkaline hematin method for measuring menstrual blood loss--a modification and its clinical use in menorrhagia.

Direct measurement of menstrual blood loss is the only reliable basis of the diagnosis 'menorrhagia'. We describe modifications of the alkaline hematin method for measuring menstrual blood loss (MBL) which improve the recovery rate from 89 to 98% and make the method more suitable for routine laboratory use. Using this modified method, 5 out of 21 patients (24%) complaining of menorrhagia and scheduled for hysterectomy had an MBL less than 80 ml, which is the upper level of normal MBL.

Subcellular distribution of androgens and oestrogens in target tissue.

To study the endogenous concentration of androgens and oestrogens in target tissue, three different methods have been used: (a) measurement of concentration gradient across mammary tumours, (b) long-term infusion of subphysiological amounts of labelled oestrogens and measurement of tissue-plasma gradients in human uterine tissue and (c) measurement of endogenous concentrations in mammary and uterine tissues. In addition to the tissue-plasma gradient, the subcellular distribution was also measured. An improved method is presented for processing the tissue and for the quantitative extraction of steroid hormones from cytosol and nuclear fraction. The data obtained show clearly that steroid hormones have a tissue-plasma gradient that varies from tissue to tissue and from one hormone to another. As steroid hormones exert their influence intracellularly at the site of receptor binding, our findings may have major consequences for the study of hormone-related cancers of the breast and of the uterus.

Serum progesterone and oestradiol concentrations in women with unexplained infertility.

Twenty-eight patients with longstanding, unexplained infertility were studied during one menstrual cycle by serial serum progesterone and oestradiol assays. For comparison the serum concentrations of these hormones were also measured during one cycle in ten fertile control subjects. Of the patients with infertility, one had an anovulatory cycle and one had a cycle with a short luteal phase. In the other 26 patients the length of the cycle, the preovulatory peak oestradiol concentration and the maximum oestradiol concentration during the luteal phase were less than in the controls but these differences were not statistically significant (p > 0.10). However, the duration of progesterone secretion and the maximum progesterone concentration during the luteal phase were significantly less (p < 0.01) in the patients with infertility than in the controls. It is, however, uncertain whether the subnormal progesterone secretion is responsible for the infertility.