A 35-year-old pregnant woman, approximately 36 weeks gestation, is admitted to the emergency department (ED) following a motor vehicle crash. She has a closed head injury, bilateral femoral fractures, and possible abdominal trauma. Her Glasgow Coma Score (GCS) is 5: she does not open her eyes (1); there is no audible vocalization (1); and she is showing decorticate rigidity (3). Her heart rate is 135 beats per minute, blood pressure 85/40 mm Hg, and respiratory rate is 40 breaths per minute and shallow. Fetal heart rate (FHR) is 110 beats per minute. The oxygen saturation (SaO₂) is 90%, on a non-rebreathing oxygen mask. A cervical collar is in place and Thomas splints are being applied to both legs.

What Are the Immediate Evaluation and Management Priorities in This Patient?

Initial evaluation and management priorities for the near-term parturient are no different than any trauma victim—assessment of airway, breathing and circulation (ABCs), followed by a secondary survey, including assessment of the abdomen and fetus.

Unique considerations related to the pregnancy, such as supine hypotensive syndrome and the significant capillary engorgement of the nasal and oropharyngeal mucosa, may impact positioning, hemodynamics, and airway management.¹

Immediate attention is directed toward the airway. Her GCS and oxygen saturations mandate endotracheal intubation and ventilation. She is not a crash airway, and therefore an evaluation for difficulty is performed employing the MOANS, LEMON, CRANE, RODS, and SHORT mnemonics (see sections “Difficult BMV: MOANS,” “Difficult DL Intubation: LEMON,” “Difficult VL Intubation: CRANE,” “Difficult Use of an EGD: RODS,” and “Difficult Cricothyrotomy: SHORT” in Chapter 1). In this particular patient, difficulty should be anticipated and an approach as suggested in the Difficult Airway Algorithm (Chapter 2) adopted, recognizing that parturients at term have a substantially elevated risk of aspiration, particularly in this circumstance where protective airway reflexes are compromised, and the patient is not responding to command.

Following airway management, attention is directed to an assessment of breathing. Her lung fields must be evaluated for presence, equality, and quality of breath sounds. This evaluation, coupled with a stat portable chest x-ray, may uncover a pneumothorax and/or hemothorax that may require treatment.

In pregnancy, minute ventilation is normally increased by approximately 45%, largely through an increase in tidal volume. This increased minute ventilation results in a fall in PaCO₂ to approximately 30 mm Hg. Therefore, one should initially moderately and empirically hyperventilate this patient. Ventilation may be guided by arterial blood gases once resuscitation has been established.

During pregnancy, an increase in gastric acid production results not only in an increased volume but a decrease in the pH. Coupled with a decrease in the competency of the lower esophageal sphincter, a greatly enhanced risk of reflux is present. The most effective protection against aspiration in this situation is the presence of a cuffed endotracheal tube in the trachea.

The final step of the primary survey is directed to the evaluation and management of the circulation. This patient is hypotensive. Positioning to minimize supine hypotensive syndrome (or aortocaval compression syndrome) and volume resuscitation should be undertaken. A wedge should be placed under the right hip to create 30 degrees of left uterine displacement. This will reduce aortocaval compression and improve systemic and placental perfusion.² Large bore IV cannula and fluids must be initiated as the parturient can lose 30% of her blood volume before demonstrating cardiovascular changes.³ There is a strong correlation between hypotension and negative outcome for both an injured brain, and a fetus in utero.

Relative anemia (approximately 11 g·dL⁻¹ or 6.9 mmol·L⁻¹), related to an enhanced blood volume, is a physiologic response to pregnancy. In a healthy near-term parturient, blood pressure may remain at near normal values until greater than 1000 mL of blood loss occurs. In addition to the usual sources of blood loss in a trauma victim, the uterus can be a source of significant hemorrhage, for example, both placental and uterine abruption may be associated with blunt abdominal trauma, such as lap belt injury.

Now the attention can be turned to the secondary survey focusing on her head injury, the abdomen, the stabilization of her fractures, and the fetus. Her GCS of less than 7 indicates a significant head injury at risk of further decompensation at any time. Securing an airway in a timely fashion may be critical in limiting hypoxic brain injury and avoiding surges in intracranial pressure (ICP) related to elevations of PaCO₂.⁴

What Is Unique About Managing the Airway Urgently in the Traumatic Brain-Injured Patient Who Also Happens to be a Near-Term Parturient?

As discussed above, the practitioner must deal with conflicting priorities: the patient has features suggestive of difficult intubation, specifically, difficult bag-mask-ventilation (BMV) and difficult extraglottic device (EGD) use. A secondary concern is suspicion of blunt chest trauma. Acute severe head injury and the risk of aspiration mandate a need for rapid and atraumatic intubation guided by the principles of airway evaluation and management articulated in Chapter 2.

The practitioner has time to call for help and a Difficult Airway Cart, as the SaO₂ is acceptable, while borderline, and the FHR is normal. The airway practitioner should begin denitrogenation quickly using a mask with a rebreathing bag, and 15 L·min⁻¹ of flesh gas flow with oxygen.

Assisted ventilation may be required, taking care to avoid gastric insufflation. The rapid respiratory rate makes this a challenge. If the practitioner is not confident that tracheal intubation will be successful in their hands, or that the ability to provide gas exchange using BMV or EGD will be successful following induction and paralysis, an “awake look” with a laryngoscope (direct laryngoscopy [DL] or indirect (video) laryngoscopy [VL]) will influence decisions to employ RSI pathway or move directly to a front of neck access. The need to keep the C-spine immobilized may also influence this decision.

Should RSI be selected in the setting of a patient with acute severe head injury, the administration of pretreatment agents to attenuate rises in ICP may be prudent (see Chapter 17). The selection of an induction agent and the dose employed will be guided by the degree of hemodynamic stability, and in this case, is likely to be etomidate at a reduced dose (e.g., 0.2 mg·kg⁻¹). The dose of the neuromuscular blocker, such as succinylcholine, is never modified and is 1.5 mg·kg⁻¹.

Alternatively, an “awake look” with a DL or VL to determine suitability for tracheal intubation may be performed. This patient has a GCS of 5 and may not require sedation (e.g., etomidate titration). However, patients with acute severe head injury may present with a clenched jaw, prohibiting an awake look. If this occurs, the only options are RSI and cricothyrotomy.

Induction of anesthesia and muscle paralysis must be prepared prior to securing the airway. A selection of intubation and rescue airway devices familiar to the airway practitioner must also be prepared. In this case, laryngoscopic intubation is judged to be highly likely (Plan A). Plan B is to use an EGD, preferably one that permits intubation through it (e.g., LMA-Fastrach), and Plan C is a front of neck access in the event that both fail. Following denitrogenation with 100% oxygen, pretreatment as indicated, and the application of nasal prong oxygen at 10 to 15 L·min⁻¹, induction and paralytic medications are administered and the application of cricoid pressure by an experienced assistant is undertaken. A third assistant maintains manual in-line stabilization of the neck, and the trachea is successfully intubated. After detection of end-tidal carbon dioxide confirms tracheal placement, the endotracheal tube is secured. An orogastric tube may be placed to remove gastric content to reduce the risk of aspiration.