Pulmonary pharmacology

Agreement of umbilical cord drug and cotinine levels with maternal self-report of drug use and smoking during pregnancy

OBJECTIVE

We undertook this study to assess the agreement between fetal umbilical cord drug levels and maternal self-report.

STUDY DESIGN

Cord samples were collected from 103 placentas after delivery as a subproject of the larger Pacific Research Center for Early Human Development (PRCEHD) study. These cord samples were then processed to obtain cord lysates and enzyme-linked immunosorbent assay (ELISA) performed for cotinine and illicit drugs. Levels of each of these substances were compared with clinical information.

RESULT

We found fair agreement between self-reported smoking and cotinine levels (κ = 0.26 (0.07 to 0.5)) as well as slight agreement with current drug use and positive drug levels (κ = 0.19 (-0.05 to 0.4)). Compared with maternal self-report, sensitivity of cotinine levels was 27% and specificity was 98%. Sensitivity of positive cord illicit drug levels was 32% and specificity was 85%.

CONCLUSION

Umbilical cords provide another independent measure of maternal drug use and are readily available. To our knowledge, this is the first study to measure cotinine levels in the umbilical cord tissue.

Acute and chronic respiratory diseases in pregnancy: associations with placental abruption

OBJECTIVE

This study was undertaken to examine the associations between maternal respiratory diseases and placental abruption.

STUDY DESIGN

A population-based, retrospective cohort study was conducted to examine the associations between maternal respiratory diseases and abruption in the United States. Data on women who delivered singleton births (n = 37,314,022) were derived from the National Hospital Discharge Survey for the years 1993 to 2003. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes were used to identify pregnant women hospitalized for acute upper respiratory diseases, viral and bacterial pneumonia, acute bronchitis, and acute bronchiolitis, chronic bronchitis, asthma, and abruption. Relative risk (RR) and 95% CI were derived from multivariable logistic regression models to evaluate the associations after adjusting for maternal age, race, marital status, smoking, cocaine use, adequacy of prenatal care, maternal insurance status, geographic location, and year of birth (although data on smoking and cocaine use are likely underreported).

RESULTS

The rate of abruption was 9.7 per 1,000 singleton births. The overall rate for acute respiratory conditions was 2.2 per 1000 pregnancies. Acute upper respiratory diseases (RR 3.2, 95% CI 3.0-3.4) and viral/bacterial pneumonia (RR 2.2, 95% CI 1.9-2.4) were associated with abruption. The rate of chronic respiratory conditions was 9.0 per 1,000 pregnancies. Chronic bronchitis was strongly associated with abruption (RR 31.8, 95% CI 29.6-34.3), but the association between asthma and abruption was modest (RR 1.1, 95% CI 1.0-1.2). Stratified analysis by maternal race showed that asthma was associated with abruption among black women but not white women.

CONCLUSION

Pregnancies complicated by acute and chronic respiratory diseases requiring hospitalization are associated with placental abruption.

The Sympathomimetic Actions of l-Ephedrine and d-Pseudoephedrine: Direct Receptor Activation or Norepinephrine Release?

The basic mechanisms by which ephedrine is preferred over other vasopressors in obstetric anesthesia have not been clearly defined. We examined the sympathomimetic effects of l-ephedrine, currently used as a vasopressor, and d-pseudoephedrine, currently used as a decongestant. In anesthetized rats, l-ephedrine and d-pseudoephedrine caused dose-dependent increases in arterial blood pressure and heart rate, and these effects disappeared after destruction of the sympathetic nerve terminals with 6-hydroxydopamine (6-OHDA) pretreatment. The two ephedrine isomers produced concentration-dependent increases in tension of anococcygeal muscle and sinus rate of right atrium from rats. However, the anococcygeal and atrial responses to d-pseudoephedrine were abolished after 6-OHDA pretreatment, whereas approximately 50% of the responses to l-ephedrine were 6-OHDA-resistant. In human umbilical artery and vein, the two isomers failed to generate any contraction when given at the concentration that is capable of producing significant effects on anococcygeal and atrial tissues. Although direct adrenoceptor activation with l-ephedrine was detectable at tissue levels, the pressor response in vivo was entirely attributable to norepinephrine release from sympathetic nerves. This indirect mechanism could partly explain why l-ephedrine is better at increasing maternal arterial blood pressure while preserving the uteroplacental blood flow that is devoid of the involvement of the sympathetic innervation.

IMPLICATIONS

The indirectly sympathomimetic property of l-ephedrine may be one of the mechanisms to explain why ephedrine is preferred over alpha-adrenergic agonists as a vasopressor for treatment of intraspinal anesthesia-induced hypotension in obstetrics.

Breastfeeding and over-the-counter medications

A breastfeeding mother is confronted with a wide variety of over-the-counter products, necessitating careful guidance from her health care professional. This article presents a discussion and comprehensive tables that cover, by category, over-the-counter medications that nursing mothers may need to take. These tables should greatly assist the health care professional in the important task of counseling the nursing mother about the proper use of over-the-counter medications. This information will enable health care professionals to interpret information on the topic of over-the-counter medications and breastfeeding; list medications, in specific over-the-counter categories, that are usually safe to take while breastfeeding; recommend over-the-counter medications of choice for a breastfeeding mother; and generally counsel a breastfeeding mother who is taking or expects to take over-the-counter medications.

Bronchodilator therapy for chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of diseases characterized by cough, sputum production, dyspnoea, airflow limitation and bronchial hyperreactivity. The airflow limitation declines progressively and is irreversible or partially reversible. Bronchodilator therapy is prescribed to relieve the symptoms, reverse airway obstruction and hopefully slow the rate of disease progression and decelerate the decline in pulmonary function. During acute exacerbation, inhalation of beta2-agonists remain the therapy of choice. The usefulness of anticholinergic inhalation in acute attacks is investigated in order to determine if a higher dose and more frequent administration have same benefit as beta2-agonists inhalation. Theophylline is usually given orally as a sustained release formulation for chronic maintenance therapy. Some patients may benefit from theophylline infusion during an acute phase when appropriately used; however, sympathomimetic agents fail to produce adequate bronchodilation. During interim periods of stability, inhalation of ipratropium bromide has increased in popularity as a regular long-term bronchodilator therapy. Although ipratropium and beta2-agonists are equally efficacious when the dosage is adequate enough, a combination of both provides a rapid onset of action of the adrenergic agents and a prolonged action of the anticholinergic. Furthermore, this combination can be given in a reduced dose, thereby avoiding side-effects. Inhalation techniques can influence the efficacy of bronchodilator therapy. For severe dyspnoeic patients or patients with poor technique of co-ordination with metered-dose inhaler (MDI), attachment of a spacer to the MDI or using a nebulizer will overcome these difficulties. Bronchodilator therapy can not prevent the development of COPD or slow down the decline of pulmonary function, other interventions should be included in a comprehensive management programme.