Noninvasive ventilatory support does not facilitate recovery from acute respiratory failure in chronic obstructive pulmonary disease

This investigation evaluates, in a prospective, randomized and controlled manner, whether noninvasive ventilatory support (NIVS) with bilevel positive airway pressure (BiPAP) facilitates recovery from acute respiratory failure (ARF) in patients with chronic obstructive pulmonary disease (COPD). Twenty four patients (mean age (+/-SEM) 68 +/- 2 yrs) with COPD (forced expiratory volume in one second (FEV1) at discharge 33 +/- 2% predicted), who attended the emergency room because of ARF (pH 7.33 +/- 0.01; arterial oxygen tension (Pa,O2) 6.0 +/- 0.2 kPa; arterial carbon dioxide tension (Pa,CO2) 7.9 +/- 0.3 kPa), were initially randomized. Four out of the 14 patients (29%) allocated to received NIVS did not tolerate it. Of the remaining 20 patients, 10 received NIVS with BiPAP in a conventional hospital ward during the first 3 days of hospitalization (two daytime sessions of 3 h duration each). All 20 subjects were treated with oxygen, bronchodilators and steroids. On the first and third hospitalization days, before and 30 min after withdrawing oxygen therapy and/or BiPAP ventilatory support, we measured peak expiratory flow, arterial blood gas values, ventilatory pattern, occlusion pressure (P0.1), and maximal inspiratory (MIP) and maximal expiratory (MEP) pressures. All patients were discharged without requiring tracheal intubation and mechanical ventilation. Hospitalization time was similar in both groups (11.3 +/- 1.3 vs 10.6 +/- 0.9 days, control vs BiPAP, respectively). Arterial oxygenation, respiratory acidosis and airflow obstruction improved significantly throughout hospitalization in both groups. By contrast, the ventilatory pattern, P0.1, MIP and MEP did not change. NIVS with BiPAP did not cause any significant difference between groups. We conclude that noninvasive ventilatory support with bilevel positive airway pressure does not facilitate recovery from acute respiratory failure in patients with chronic obstructive pulmonary disease. Furthermore, a substantial proportion of patients (29%) do not tolerate noninvasive ventilatory support under these circumstances. From these results, we cannot recommend the use of noninvasive ventilatory support with bilevel positive airway pressure in the routine management of chronic obstructive pulmonary disease patients recovering from acute respiratory failure.

Continuous positive airway pressure is effective in treating upper airway oedema

The case of a patient with diffuse idiopathic skeletal hyperostosis (DISH) and upper airway oedema, is described. The patient presented with alveolar hypoventilation and obstructive apnoeas during sleep. Intravenous steroids (methylprednisolone, 160 mg.day-1) for 5 days did not reduce the oedema. However, it was rapidly reversed by the use of nasal continuous positive airway pressure (nCPAP). In addition, daytime pulmonary gas exchange was improved and sleep apnoea abolished. This beneficial effect made tracheostomy unnecessary. This case report suggests that CPAP can be a potentially useful therapeutic alternative to tracheostomy in the clinical management of upper airway oedema.

Undetectable luteinizing hormone levels using a monoclonal immunometric assay

Previous studies have shown wide discrepancies among the results obtained with different immunometric assays. We present five cases (out of 4000 women) whose plasma luteinizing hormone was not detected using a LH immunometric assay (LH Stratus Baxter) but was recognized by other kits. These cases concerned one 28-year-old woman presenting with infertility and four postmenopausal women. The LH Amerlite kit gave detectable but low results. The results obtained with the other kits were > 7 IU/l. FSH levels were > 7 IU/l. In one case, sera were taken before and after the menopause; differences between the LH results increased. Discrepancies among LH assay kits have been attributed to variation both in standard curve calibration and in epitope specificity of the kit monoclonal antibodies. The Baxter kit might misrecognize some isoforms present in postmenopausal women. The present data illustrate the potential false results with such immunoassays in routine clinical laboratory testing. When undetectable LH results are not clinically explained or when disparities between LH and FSH are observed, we suggest using a second methodology or a bioassay if necessary. Improvement in LH assays and standardization might resolve the problem of discrepancies between the LH results.

[Compliance with nasal continuous positive airway pressure (CPAP) treatment in sleep apnea-hypopnea syndrome]

Ever since Sullivan introduced nighttime nasal continuous pressure on the upper airway (CPAP) in 1981 it has been the standard treatment for sleep-hypopnea syndrome (SAHS). However, CPAP is carried out at great expense and is not tolerated by all patients. Moreover, its efficacy is dependent on the degree of compliance. In this study we set out to analyze the degree of compliance with CPAP over the first 3 months of treatment in a group of 142 consecutive patients with moderate to severe SAHS (apnea-hypopnea index: 48.9 +/- 20). Diagnosis and measurement of the level of CPAP needed (9.6 +/- 2.5 cm H2O) were based on polysomnography. Eighteen (13%) patients did not return for follow-up evaluation. In the remaining 124 patients (age 54 +/- 11 years) compliance with treatment was evaluated by way of a sleep diary in which the patient recorded the hours CPAP was used at night; this record was compared with readings from the CPAP generator's counter. All subjects were asked about their degree of sleepiness before treatment by way of a standard questionnaire. Although most patients reported regular use of CPAP in diaries, only about 60% actually used it for longer than a mean 4.5 hours daily. The most compliant patients could not be differentiated from the least compliant with respect to degree of initial sleepiness, apnea-hypopnea-per-hour index or level of CPAP required.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating chromogranin A and catecholamines in human fetuses at uneventful birth

Chromogranin A (CGA), a large acidic 48-kD protein, costored and coreleased by exocytosis with catecholamines, has been shown to be a precursor of peptides that exert feedback regulatory control on catecholamine secretion. In plasma, CGA levels increase in response to a large-amplitude physical stimulation in adult subjects and may be related to catecholamine levels. Any skin information is not yet available when the sympathoadrenal system is highly active during birth. This activation is strongly related to parturition circumstances such as the mode of delivery. The aim of our study was to determine CGA plasma levels in infants delivered vaginally or by elective cesarean section and to investigate the possible correlation between CGA and catecholamine concentrations. Plasma levels of catecholamines (norepinephrine and epinephrine) and CGA were assessed by HPLC with electrochemical detection and immunoenzymology, respectively. CGA and norepinephrine concentrations were significantly higher (p < 0.0002 and p < 0.02) in infants vaginally born than in the group delivered by elective cesarean section. A significant relationship (p < 0.04) was found between CGA and norepinephrine levels. However, for epinephrine, no significant difference was found between both groups. These results demonstrate the fetus' ability to corelease CGA and norepinephrine massively in response to stress of birth.

Sleep-related respiratory disturbances in patients with Duchenne muscular dystrophy

Sleep-related respiratory disturbances (SRD) in patients with muscle diseases may have significant clinical implications, because the patients frequently die at night. The aims of the study were to :1) assess the presence and severity of sleep-related respiratory disturbances in patients with Duchenne muscular distrophy (DMD); and 2) investigate the relationship of sleep-related respiratory disturbances to daytime symptoms and pulmonary function. We studied six clinically stable patients with Duchenne muscular dystrophy, mean age (+/- SD) 18 +/- 2 yrs. Vital capacity was 27 +/- 19% of predicted and daytime arterial oxygen tension (PaO2) was 10.9 +/- 1 kPa (range 8.9-12.4 kPa). The presence of daytime somnolence, insomnia, headache, nightmares and/or snoring was recorded. Four patients (67%) showed symptoms that suggest sleep-related respiratory disturbances. At night, the apnoea-hypopnoea index (AHI) was 11 +/- 6. The patients with more symptoms during the daytime had the highest AHI scores. Most of the apnoeas (85%) were central, particularly during rapid eye movement (REM) sleep. Sleep architecture was well-preserved. Arterial desaturation (> 5% below baseline) occurred during 25 +/- 23% of total time. AHI correlated with daytime PaO2, and AHI in REM sleep correlated with age. A stepwise multivariate analysis showed that PaO2 and, to some extent, the degree of airflow obstruction were significantly correlated with AHI. We conclude that sleep-related respiratory disturbance are frequently present in patients with Duchenne muscular dystrophy. Therefore, physicians should look for symptoms related to sleep-related respiratory disturbances in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibin as a marker for hydatidiform mole: a comparative study with the determinations of intact human chorionic gonadotrophin and its free beta-subunit

OBJECTIVE

The purpose of the study was to evaluate plasma inhibin as a marker of hydatidiform mole and to compare the results with intact human chorionic gonadotrophin (hCG) and its free beta-subunit.

DESIGN

Serial determinations of the plasma concentrations of inhibin, intact human chorionic gonadotrophin and its free beta-subunit in cases of hydatidiform mole over an average period of 140 days.

PATIENTS

Five cases of hydatidiform mole, including patients with spontaneous remission after evacuation or persistent trophoblastic disease.

MEASUREMENTS

Immunoreactive inhibin, hCG and free hCG beta-subunit were measured using standard enzyme immunoassays.

RESULTS

Inhibin and free hCG beta-subunit levels were greater than in normal pregnant women at the same gestational age. Only intact hCG could detect the persistence of trophoblastic tissue.

CONCLUSIONS

Our data suggest that inhibin, intact human chorionic gonadotrophin and free beta-subunit might be useful as diagnostic markers of molar pregnancies. However, the original method of intact hCG determination is still superior for follow-up.

[Lead poisoning in pregnancy]

Endemic areas of lead poisoning have recently been rediscovered raising an important public health problem, particularly for pregnant women and their offspring. Theoretically, pregnant women can no longer be exposed to occupational sources with the application of public health regulations but other sources including water contamination, wall paint, industrial wastes and automobile exhaust fumes cannot be ignored. The placental barrier is permeable to free serum lead and levels in cord blood reaches 5 to 10% of the maternal blood level. In addition, lead may be released from maternal bone reserves during pregnancy and thus become a major source of intoxication for the fetus. Lead content in fetal organs increases with gestational age and may affect the nervous system and calcium dependent organs. Moderate lead levels of 100 micrograms/L can inhibit fetal haeme and erythropoiesis. Besides the classical signs of lead poisoning, pregnant women risk spontaneous abortion and increased blood pressure. Manifestations in the fetus and newborn include prematurity, fetal hypotrophy and malformations. Other manifestations are not seen until several years after birth and include retarded mental development and muscular and behaviour disorders. Diagnosis is based on screening tests which should be used in cases of suspected accidental or environmental intoxication. Tests should include assay of zinc protoporphyrins and aminolevulinic acid dehydrase. A search for the source of the contamination should be undertaken when blood levels above 250 micrograms/L are observed. Treatment with metal chelators is not recommendable (except in extreme life-threatening cases) during pregnancy due to their teratogenic effect. Prevention is the only adequate treatment.

[Bronchiolitis obliterans with organizing pneumonia]

We present a typical case of Obliterant Bonchilitis with Organizative Pneumonia in a 73-years-old man. The diagnosis was established through minithoracotomy. Treated with high dosage of methylprednisolone, the clinical-radiological evolution was satisfactory. It is very important to know and correctly diagnose this entity, given its excellent therapeutical response.

[Disorders of hemostasis in dysthyroidism]

Many potentially severe hemostatic disorders have been reported in thyroid diseases. Hyperthyroidism has been associated with thrombocytopenia, coagulation factor abnormalities, and decreased fibrinolytic and plasminogen activities. In hypothyroidism, potentially severe hemorrhagic disorders have been reported, including platelet function abnormalities and coagulation factor alterations such as acquired von Willebrand disease.

[The evaluation of the oxygen-conserving valve during exertion]

BACKGROUND

The oxygen-conserving valve (OCV) permits reduction in oxygen consumption upon the release of oxygen only during inhalation thereby increasing the autonomy of portable sources.

METHODS

In order to confirm its efficacy during exercise, 15 patients with chronic limitation of air flow and gasometric criteria of domiciliary oxygen therapy were selected. The patients underwent three walking tests (WT) of 6 minutes during which the continuous form of transcutaneous hemoglobin saturation (SaO2) and the distance covered were registered. The first was carried out breathing synthetic air at a flow of 2 liters per minute; the second with continuous oxygen released by a portable source at 2 liters per minute and the third with the OCV coupled to a portable source at the same flow.

RESULTS

SaO2 reached with the continuous oxygen is significantly higher to that of synthetic air while there was no difference between the SaO2 with continuous oxygen and with valve. Improvement in SaO2 upon use the valve was not obtained in only 2 of the 15 patients. A significant increase was observed in the distance covered upon oxygen administration not only in the continuous form but also with OCV with respect to synthetic air.

CONCLUSIONS

OCV is as effective as continuous oxygen in the correction of desaturation during exercise, however its indications must be individualized by exercise tests (WT) in each patients in order to ensure its correct functioning.

[The introduction of liquid oxygen as a portable source in continuous home oxygen therapy]

The most widespread types of oxygen delivery at home in our area are bottles where the gas is stored under pressure and concentrators. Both devices can only be used at rest. We have assessed a new system for the delivery of liquid oxygen to be used at home, provided with a portable unit which permits that the patients receive oxygen also outside their homes. Seven such devices have been implemented in the Barcelona area, with an excellent acceptance and without technical problems. To verify the clinical indication, exercise tests were carried out both in baseline conditions and receiving oxygen from the portable source. Oxyhemoglobin saturation and the walked distance were continuously measured. In all patients important drops in the saturation of oxyhemoglobin were recorded during walking, which was corrected with oxygen administration. Liquid oxygen with a portable source is a good delivery system for oxygen therapy at home, permitting to receive oxygen throughout the day, particularly during exercise. Although the availability of liquid oxygen is limited, it should be recommended to the patients in whom exercise hypoxemia is shown to be corrected and who desire an active social life.