Anesthesia for Cesarean Delivery in a Patient with an Undiagnosed Traumatic Diaphragmatic Hernia

A 19-yr-old gravida 3 para 0 woman, 361/7 weeks’ gestational age in active labor, was transferred to our institution with a 2-day history of severe left upper quadrant pain and dyspnea. She had sustained a stab wound to the left side of the chest 3 yr ago and did not require surgical intervention. Past history included appendectomy and asthma. There had been no asthma exacerbations for the past 2 yr, and she was not taking daily asthma medications. Her previous two pregnancies had ended in miscarriages at 5 months (3 yr previously) and at 4 months (1 yr previously), respectively. Medications were prenatal vitamins and iron.

Blood pressure was 121/83 mmHg, pulse was 131 beats/min, respiration was 28 breaths/min, temperature was 36.7°C, oxygen saturation was 96% on 4 l O²via  nasal cannula. Breath sounds were absent on the left side, and the trachea was deviated to the right. There was no wheezing. Cardiovascular examination showed tachycardia, and the point of maximal impulse was displaced to the right. Fetal heart rate was decreased with late decelerations. The patient was transferred to the operating room for urgent cesarean delivery. Left-sided uterine displacement was performed. However, because of concerns for maternal safety, a portable chest radiograph was obtained, which showed total opacification of the left hemithorax with rightward displacement of mediastinal structures.

The membranes were artificially ruptured, and internal fetal heart rate monitoring was instituted. Thoracic and trauma surgery staff were consulted. Meperidine, 25 mg, was administered intravenously, and a left-sided chest tube was inserted using local anesthesia. Approximately 1,200 ml blood-tinged fluid was drained, and clinically, the patient was less dyspneic. Nonreassuring fetal status persisted, and the scalp pH was 7.20. Thirty milliliters sodium citrate was administered orally. Spinal anesthesia was performed with the patient in the sitting position with 12 mg hyperbaric bupivacaine, and a T6 level was obtained. Forty milligrams intravenous ephedrine, in incremental doses, was required to maintain blood pressure between 105/40 and 120/50 mmHg. Heart rate was 130–140 beats/min, and oxygen saturation measured by pulse oximetry (Spo²) was 97–100% with 10 l O²/min via  a nonrebreathing face mask. A healthy female infant was delivered 4 min after incision. Twenty milligrams intravenous ketamine was required for analgesia during delivery.

Postoperatively, a computed tomography scan of the chest showed a defect in the anterior aspect of the left hemidiaphragm dome, with herniation of bowel and mesentery into the left hemothorax and almost complete left lung collapse (figs. 1 and 2). The patient was admitted to the intensive care unit. On postoperative day 1, the patient experienced worsening dyspnea and tachypnea and was thought to have pneumonia. The leukocyte count was 22,000, and the hematocrit was 23%. The echocardiogram showed a large pericardial effusion and diastolic right atrial collapse, indicative of hemodynamically significant pericardial tamponade. A subxiphoid pericardiostomy was performed during general anesthesia. Ketamine, 120 mg, and succinylcholine, 100 mg, were used at induction. Isoflurane, 0.4–0.6% inspired, fentanyl, 100 μg, and rocuronium, 50 mg, were used during maintenance. In addition to standard monitors, direct arterial blood pressure monitoring was performed. Two units packed erythrocytes were administered.

After surgery, the patient’s trachea remained intubated, and she required treatment for multiple medical problems, including acute respiratory distress syndrome, septicemia, pneumonia, and venous thromboembolism. Blood cultures were positive for Gram-negative organisms. Because of her severe hypoxemia and compromised respiratory status, a decision was made to delay repair of the diaphragmatic hernia. One month later, she underwent left thoracotomy for debridement of necrotic colon, decortication of left lung, primary repair of diaphragmatic hernia, transverse colectomy with anastomosis, tracheostomy, and gastrostomy tube placement. Postoperatively, acute pancreatitis developed in the patient. She was discharged to rehabilitation care 3 months after her cesarean delivery. Two months later, her tracheostomy and gastrostomy tubes were removed, and she was discharged home, independent for activities of daily living and able to care for her healthy child.

Diaphragmatic injuries occur frequently after penetrating thoracoabdominal trauma, with an incidence of 13–19%. 9–11The majority of injuries are located near the site of entrance to the chest wall, and the wound size averages 2–4 cm. 10,12Diaphragmatic rupture after blunt trauma (e.g. , motor vehicle accident) is less common, with an incidence of approximately 5%. 13Because the diaphragm is in constant motion, spontaneous healing after injury is unlikely. In fact, most defects tend to enlarge or result in strangulation of herniated organs or portions of omentum. The colon is the most commonly herniated viscus, as in the current patient. The stomach, omentum, small bowel, and liver may also herniate through the traumatic rupture, depending on the anatomic location of the tear.

After diagnosis, surgical treatment is required to avoid strangulation of herniated organs. 8,13During pregnancy and labor, there is increased risk of herniation and strangulation because the enlarged uterus forces increasing amounts of abdominal contents into the chest. Any patient with abdominal viscera occupying a large portion of the chest must be considered at risk of regurgitation, aspiration, hypoxemia, and hemodynamic compromise. 14Tracheal intubation difficulties may also be encountered because of mediastinal shift and deviation of the trachea. The mortality rate of chronic incarcerated diaphragmatic hernia can be as high as 20%, whereas that of strangulated hernias may approach 85%. 10,15 

Spinal anesthesia was chosen to minimize the risk of aspiration associated with general anesthesia. The use of regional anesthesia also helps to minimize the risk of maternal hypoxemia caused by the collapsed lung and avoids the need for tracheal intubation and airway instrumentation, which might precipitate bronchospasm, given the history of asthma. Nonetheless, it is recognized that respiratory compromise can still occur with regional anesthesia, especially with high sensory levels, because of blockade of the muscles of respiration and reduction of the inspiratory capacity and expiratory reserve volume. 16 

Use of general anesthesia and positive-pressure ventilation may be advantageous in patients with traumatic diaphragmatic hernia to expand the atelectatic lung, increase functional residual capacity, and deliver high concentrations of oxygen. However, large tidal volumes and high peak airway pressures are not recommended because of the risk of barotrauma to the nonaffected lung. Moreover, large tidal volumes and high airway pressures may decrease venous return and cardiac output with resultant maternal hypotension and diminished uterine blood flow and placental perfusion. Nitrous oxide is best avoided in situations of bowel obstruction and strangulation because it can expand the air-filled bowel and aggravate the mediastinal shift.

Pericardial tamponade has previously been associated with traumatic diaphragmatic hernia due to herniation of bowel into the pericardial sac 5and due to accumulation of fluid within the pericardial space. Echocardiography is especially useful in these situations, as demonstrated by Colliver et al.  4and Fleyfel et al.  17Echocardiography can also be used to examine trauma patients rapidly with regard to cardiac anatomy and function (e.g. , blunt or penetrating cardiac injury), as well as the integrity of the thoracic aorta. 18,19Anesthetic goals for patients with acute tamponade include maintaining myocardial contractility, cardiac preload, heart rate, and systemic vascular resistance. 20Ketamine remains an excellent choice for induction of anesthesia in these situations. Ketamine produces sympathetic nervous system stimulation with increased heart rate, blood pressure, and cardiac output. However, ketamine may cause direct myocardial depression and result in hypotension and decreased cardiac output if catecholamine stores are depleted or if there is exhaustion of sympathetic system compensatory mechanisms. Pericardiocentesis performed with local anesthesia before induction of general anesthesia was not an option in the current patient because of the presence of herniated bowel within the mediastinum.

The timing of surgical interventions was clearly of major importance in this patient. Delay in repair of the diaphragmatic hernia was chosen because of acute respiratory distress syndrome and sepsis, thought to be caused by pneumonia and not necrotic bowel. Surgery was performed as soon as it was recognized that her bowel was ischemic. In retrospect, there was a window of approximately 24 h postpartum when she could have undergone thoracotomy and laparotomy before the onset of acute respiratory distress syndrome. After acute respiratory distress syndrome developed, it was believed that she would not survive surgical repair of the diaphragmatic hernia.

In summary, we present a case of a delayed diagnosis of traumatic diaphragmatic hernia in a pregnant patient. The importance of the preanesthetic evaluation, including history and physical examination, is emphasized. A high index of suspicion for diaphragmatic hernia is necessary in any obstetric patient with a history of penetrating thoracoabdominal trauma. The increased intraabdominal pressures during pregnancy and labor can predispose to strangulation, which is associated with significant morbidity and mortality. Radiographic evaluation of the chest, including chest computed tomography, are diagnostic.

The authors thank Leroy Dierker, M.D. (Department of Obstetrics and Gynecology, MetroHealth Medical Center [MHMC], Cleveland, OH); Norman Snow, M.D. (Division of Thoracic Surgery, MHMC); William Fallon, M.D., and Charles Yowler, M.D. (Division of Trauma Surgery, MHMC), for managing the obstetrical and surgical issues; Harris Freed, M.D. (Department of Radiology, MHMC), for radiologic interpretation; and all MetroHealth personnel involved in the care of the patient and her child.