O'Sullivan (2009) randomized 2426 low-risk nulliparas to consume either water and ice chips alone or small amounts of bread, biscuits, vegetables, fruits, yogurt, soup, and fruit juice. Approximately 30 percent of women in each arm of the study underwent cesarean delivery. No cases of aspiration occurred during the study, although approximately a third of women in each study arm vomited during labor or delivery. Epidural analgesia during labor was used in this study, although the authors did not report the type of anesthesia used for cesarean deliveries. Presumably, neuraxial analgesia was used, and this greatly minimized the pulmonary aspiration risk. Given the low prevalence of aspiration, this trial was not powered to measure whether feeding during labor was safe (Sperling, 2016).
In 1952, Teabeaut demonstrated experimentally that if the pH of aspirated fluid was <2.5, severe chemical pneumonitis developed. It was later demonstrated that the pH of gastric juice in nearly half of women tested intrapartum was <2.5 (Taylor, 1966). The right mainstem bronchus usually ofers the simplest pathway for aspirated material to reach the lung parenchyma, and therefore, the right lower lobe is most often involved. In severe cases, there is bilateral widespread involvement.
The woman who aspirates may develop evidence of respiratory distress immediately or several hours after aspiration, depending in part on the material aspirated and the severity of the response. Aspiration of a large amount of solid material causes obvious airway obstruction. Smaller particles without acidic liquid may lead to patchy atelectasis and later to bronchopneumonia.
When highly acidic liquid is inspired, decreased oxygen saturation along with tachypnea, bronchospasm, rhonchi, rales, atelectasis, cyanosis, tachycardia, and hypotension are likely to develop. At the injury sites, there is pulmonary capillary leakage and exudation of protein-rich fluid containing numerous erythrocytes into the lung interstitium and alveoli. his causes decreased pulmonary compliance, shunting of blood, and severe hypoxemia. Radiographic changes may not appear immediately, and these may be variable, although the right lung most often is afected. hus, chest radiographs alone should not be used to exclude aspiration.
he methods recommended for treatment of aspiration have changed appreciably in recent years, indicating that previous therapy was not very successful. Suspicion of aspiration of gastric contents demands close monitoring for evidence of pulmonary damage. Respiratory rate and oxygen saturation as measured by pulse oximetry are the most sensitive and earliest indicators of injury.
Inhaled luid should be immediately and thoroughly wiped from the mouth and removed from the pharynx and trachea by suction. Saline lavage may further disseminate the acid throughout the lung and is not recommended. If large particulate matter is inspired, bronchoscopy may be indicated to relieve airway obstruction. No convincing evidence supports that corticosteroid therapy or prophylactic antimicrobial administration is beneicial (Marik, 2001). If infection develops, however, then vigorous treatment is given. If acute respiratory failure develops, mechanical ventilation with positive end-expiratory pressure may be lifesaving (Chap. 47, p. 919).
patient satisfaction, minimizing side efects, aiding unctional capacity, and preventing prolonged hospital stays (Lavoie, 2013). In a prospective study, 96 percent of women reported pain immediately ater delivery (Eisenach, 2008). he incidence of persistent pain 1 and 2 years following cesarean delivery was reported to approximate 20 percent (Hannah, 2004; Kainu, 2010).