Diagnostic imaging of the lung during pregnancy

Acute respiratory failure and mechanical ventilation in pregnant patient: A narrative review of literature

Physiological changes of pregnancy imposes higher risk of acute respiratory failure (ARF) with even a slight insult and remains an important cause of maternal and fetal morbidity and mortality. Although pregnant women have different respiratory physiology and different causes of ARF, guidelines specific to ventilatory settings, goals of oxygenation and weaning process could not be framed due to lack of large-scale randomized controlled trials. During the 2009 H1N1 pandemic, pregnant women had higher morbidity and mortality compared to nonpregnant women. During this period, alternative strategies of ventilation such as high-frequency oscillatory ventilation, inhalational of nitric oxide, prone positioning, and extra corporeal membrane oxygenation were increasingly used as a desperate measure to rescue pregnant patients with severe hypoxemia who were not improving with conventional mechanical ventilation. This article highlights the causes of ARF and recent advances in invasive, noninvasive and alternative strategies of ventilation used during pregnancy.

Case Studies

Ms A was a 28 year old woman in her second pregnancy (she had one previous termination of pregnancy) who booked-in at 19 weeks’ gestation. She was known to have sickle cell disease (specifically sickle cell anaemia [HbSS]), and her last crisis had occurred 3 years before this pregnancy.

Stroke in pregnancy

Stroke in pregnancy and the puerperium is a rare but serious cause of maternal and fetal mortality. Pregnancy-associated maternal changes should remain additional considerations in the evaluation and treatment of the pregnant patient who has stroke and not preclude a comprehensive stroke evaluation. Instead, the approach to the pregnant patient who has stroke should include the evaluation of general causes of stroke in the young, with the additional consideration of the rare pregnancy-specific causes. Understanding the potential maternal and fetal risks of diagnostic testing and treatment is crucial to appropriate decision making when caring for the pregnant patient who has stroke.

Pregnancy and lactation

Pregnancy results in physiologic changes in almost all organ systems in the body mediated mainly by female sex hormones. Physiologic changes of pregnancy influence the dental management of women during pregnancy. Understanding these normal changes is essential for providing quality care for pregnant women. This review article briefly discusses the cardiovascular, respiratory, gastrointestinal, urogenital, endocrine, and oral physiologic changes that occur during normal gestation. A summary of current scientific knowledge of ionizing radiation is presented. Information about the compatibility, complications, and excretion of the common drugs during pregnancy is provided. Drugs and their usage during breast-feeding are also discussed. Guidelines for the management of a pregnant patient in the dental office are summarized.

Treatment of community-acquired lower respiratory tract infections during pregnancy

The incidence of lower respiratory tract infection (LRTI) in women of child-bearing age is approximately 64 per 1000 population. The spectrum of illness ranges from acute bronchitis, which is very common, through influenza virus infection and exacerbations of underlying lung disease, to pneumonia, which, fortunately is uncommon (<1.5% LRTI), but can be severe.

Acute bronchitis is generally mild, self-limiting and usually does not require antibacterial therapy. Influenza virus infection in pregnant women has been recently related to increased hospitalization for acute cardiorespiratory conditions. At present, the safety of the newer neuraminidase inhibitors for the treatment of influenza virus infection has not been established in pregnancy and they are not routinely recommended. In influenza virus infection complicated by pneumonia, antibacterial agents active against Staphylococcus aureus and Streptococcus pneumoniae superinfection should be used.

There are few data on infective complications of asthma or COPD in pregnancy. The latter is rare, as patients with COPD are usually male and aged over 45 years. Management is the same as for nonpregnant patients.

The incidence and mortality of pneumonia in pregnancy is similar to that in nonpregnant patients. Infants born to pregnant patients with pneumonia have been found to be born earlier and weigh less than controls. Risk factors for the development of pneumonia include anemia, asthma and use of antepartum corticosteroids and tocolytic agents. Based on the few available studies, the main pathogens causing pneumonia are S. pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae and viruses. β-Lactam and macrolide antibiotics therefore remain the antibiotics of choice in terms of both pathogen coverage and safety in pregnancy. In HIV-infected pregnant patients, recurrent bacterial pneumonia, but not Pneumocystis carinii pneumonia (PCP), is more common than in nonpregnant patients. Trimethoprim/sulfamethoxazole (cotrimoxazole) has not definitely been associated with adverse clinical outcomes despite theoretical risks. Currently it is still the treatment of choice in PCP, where mortality remains high.

In conclusion, there are few data specifically related to pregnant women with different types of LRTI. Where data are available, no significant differences compared with nonpregnant patients have been identified. In considering the use of any therapeutic agent or investigation in pregnant patients with LRTI, safety aspects must be carefully weighed against potential benefit. Otherwise, management strategies should not differ from those for nonpregnant patients. Further research in this area is warranted.