+++
50.3.1 What Initial Preparations Should Be Made with the Obstetricians as Induction of Labor Is Undertaken?
++
One of the most important things that an anesthesia practitioner must do is to communicate with the obstetricians, the nurses, the patient, and the patient's family. The health care team and the patient/family must understand that every effort would be made to avoid the necessity for an urgent induction of general anesthesia. The reasons underlying this plan must be clearly and frankly explained. Nevertheless, all equipment must be readied for urgent induction, and obstetrically relevant protocols should be reviewed by all caregivers. Algorithms used on the obstetrical floor are quite different from the ones used in the general operating room (see Chapter 49).
+++
50.3.2 What Anesthetic Technique Would Be Most Appropriate for a Surgical Delivery of a Parturient with an Anticipated Difficult Airway?
++
Some form of regional anesthesia (epidural, spinal, continuous spinal, or combined spinal/epidural) would be the preferred management technique for a parturient with an anticipated difficult airway. However, this patient's developing coagulopathy precludes the use of a regional technique. While it is very unusual for a successful regional technique to require conversion to general anesthesia, there are reports of failed regional techniques, and circumstances may arise, necessitating induction of general anesthesia. Therefore, backup plans for induction of general anesthesia, should the need arise, must be formulated in advance.
+++
50.3.3 What Specific Equipment Should Be Available in Caring for This Patient: A Parturient with an Anticipated Difficult Airway, Short Thick Neck with Anatomy Distorted by Edema and Obesity, and at Considerable Risk for Bleeding and Excessive Secretions?
++
The operating room (OR) should be readied—the OR bed should be ramped (see Section 18.3.2) and the difficult airway cart (see Chapter 59) should be immediately available at the induction site.
++
While there are a number of alternative intubating techniques under general anesthesia, the authors believe they all have limitations. Rapid-sequence induction with direct laryngoscopy, under any circumstance, is dangerous. Techniques requiring transillumination are technically very difficult in obese patients with a short neck, or excessive neck tissue and edema. Poor neck anatomy greatly hinders rescue techniques such as transtracheal jet ventilation, cricothyrotomy, or tracheotomy. Blind nasotracheal tube placement will inevitably lead to considerable bleeding in a pregnant preeclamptic patient; and blind placement of the endotracheal tube using an Eschmann tracheal introducer, or its equivalent, requires at least some visualization of the epiglottis. There is some enthusiasm for the elective utilization of an LMA in a pregnant patient at term,17 but such advocacy is usually limited to healthy non-obese patients and is very rarely used in North America. Laryngeal mask airways such as the LMA-ProSeal™ (LMAP), or the disposable LMA-Supreme™, with incorporated esophageal vents, have the potential advantage over the LMA-Classic™ of providing some protection against the aspiration of gastric contents. Unfortunately, there are case reports of gastric regurgitation and aspiration during their use,18,19 particularly if the LMAP is not properly placed in the hypopharynx. An intubating LMA (ILMA or LMA-Fastrach™) might also be considered; however failure with these devices is not unknown.
++
In recent years there has been a profusion of video laryngoscopic devices introduced on the market. Numerous studies, in non-obstetric patients with difficult airways, report improved laryngoscopic views and intubation success rates compared with direct laryngoscopy.20-22 There are also some published reports of improved laryngoscopic views, and intubation success rates, in morbidly obese patients using video laryngoscopes. However, the results are inconsistent and vary according to particular devices and skill set of the anesthesia practitioner.23-25 There are no published reports of the success rates of these devices in obstetric patients.
++
An awake technique is probably most appropriate for this patient. A number of practitioners employ an awake look technique. That is, the airway is topicalized, or anesthetized using laryngeal nerve blocks, and then examined under direct vision using a laryngoscope. However, evidence exists of poor correlation between airway visualization in an awake patient and patients who are subsequently anesthetized and paralyzed.26
++
For this patient, the authors would choose awake intubation using a flexible bronchoscope. Sedatives and hypnotics will usually be required to facilitate an awake intubation and consideration will be required in regard to unusual sensitivity to these agents in pregnant patients, and patients with sleep apnea. In addition, potential impact of drugs and techniques on the newborn will require consideration. Pharyngeal and laryngeal structures must be anesthetized adequately for awake bronchoscopic intubation to be successful, and topicalization of the airway in edematous airways is usually difficult and requires patience. Some practitioners advocate laryngeal nerve blocks in this instance. However, in the edematous obese neck, nerve blocks are both difficult and frequently not successful.