39.6.1 What Is the Possible Role of Regional Anesthesia for This Patient?
In patients with RA and a predicted difficult airway, awake bronchoscopic intubation is considered to be the safest and the most recommended method to establish a secure airway for general anesthesia. If this plan fails or the patient refuses an awake intubation, regional anesthesia should be strongly considered as a safe alternative approach. However, not all regional techniques are 100% effective, and any type of regional anesthesia may lead to disastrous complications requiring emergency airway management.
Although these complications are inherent to all regional anesthetic procedures, the risks vary and are based on several factors, including the type of nerve block; needle insertion; type, concentration, and volume of drug administered; and patient comorbidity. Therefore, risks and benefits of regional versus general anesthesia should be considered individually for each patient. Chelly77 provides a list of important factors that should be considered in making this decision (Table 39-1).
Table 39-1 Factors Influencing the Choice of Regional Anesthesia versus Control of the Airway in Patients with Established Difficult Airways ||Download (.pdf)
Table 39-1 Factors Influencing the Choice of Regional Anesthesia versus Control of the Airway in Patients with Established Difficult Airways
- Informed consent
- Cooperative and calm
- Hemodynamically stable
- Ability to tolerate sedation, if required
- Ability to communicate with anesthesia practitioner throughout procedure
- No history of claustrophobia
- Adequate IV access
- Expertise in both regional anesthesia and difficult airway (DA) management
- Enough preoperative time to perform regional technique
- Appropriate regional technique for surgical procedure
- Prepared for alternative plans for DA
- Dependable and reliable
- Willing and able to supplement regional technique with local anesthetics, if necessary
- Cooperative with primary and alternative plans for DA management
|Types of surgery|
- Nonemergency (exception c-section)
- Short duration
- Patient position allows easy airway access
- Can be interrupted for DA management
- Limited or moderate blood loss
- Availability of appropriate equipment for regional anesthesia and DA management
- Staff (anesthesia practitioners/OR nurses)
Contraindications to regional anesthesia should be excluded. These include infection at the site of needle insertion, systemic infection, bleeding abnormalities, allergy to local anesthetics, and lack of patient cooperation.77,78 In the case of neuraxial blocks, severe hypovolemic shock, severe aortic stenosis, and high intracranial pressure should also be excluded.
Additionally, possible complications of regional anesthesia must be considered. The risk of serious complications is approximately 0.1%.79 Local anesthetic toxicity can present either with neurological or cardiovascular symptoms, such as seizures, hypotension, and cardiac arrest.
A high spinal block, as a complication of neuraxial or major plexus blockade, can result in apnea and cardiovascular collapse. These complications may require emergency airway management. Furthermore, the possibility of hemodynamic instability during the case (eg, from significant blood loss) should be considered, as this may also require emergency airway management.
It is very important as well to determine if the patient can tolerate being awake during the procedure and communicate with the anesthesia practitioner. The patient's medical condition also influences this decision. For example, if the patient has severe untreated GERD, a regional anesthetic with the patient awake may be preferable to securing the airway after induction of anesthesia. If however, diseases such as severe chronic obstructive pulmonary disease or severe corrosive RA with spinal involvement prohibit the patient from lying comfortably flat, the airway should be secured.
One of the most important factors requiring consideration is the expertise of the anesthesia practitioner. This includes the appropriate experience in the chosen regional technique, as well as adequate experience in managing the patient's airway in the event of a complication. The anesthesia practitioner must know which nerves to block for both the surgery and possible tourniquet pain. The anticipated duration of the surgical procedure should also be considered and the anesthesia practitioner must ensure that the regional anesthetic will last at least that long, if not longer should delays occur.
All of the appropriate equipment for the performance of the nerve block(s) and possible emergency airway management must be available. Additional factors to consider include the site and type of surgery. A short toe procedure requiring an ankle block will have a lower risk of complications than a revision of a total hip replacement under regional anesthesia. There must also be adequate communication and cooperation between the surgeon and the anesthesia practitioner, and both must agree on the appropriateness of regional anesthesia. Expert help should be immediately available should complications occur. If GA becomes necessary, a predetermined strategy to manage the airway should be in place, including back-up plans should the primary plan fail. The landmarks for a surgical airway should be identified before induction of GA and the necessary personnel and equipment should be immediately available.
39.6.2 Is Neuraxial Anesthesia Appropriate for This Patient?
When considering neuraxial blocks in patients with RA, spinal deformity may make the technique challenging; however, the prevalence of lumbar spine involvement in RA patients has not been found to be excessive.80 Indeed, a number of reports confirm successful use of spinal and epidural blocks for lower limb surgeries in these patients.47,81,82 Recently, there was an interesting report by Leino et al which stated that the mean spread of sensory block after the injection of plain bupivacaine was 1.5 segments higher in patients with RA than in those without this disease.81 Keeping in mind that the patient in our case has a well-known difficult airway, maximum efforts should be made to avoid excessive cephalad spread of spinal anesthetic which can cause respiratory arrest and cardiovascular collapse. To keep control over the spread of neuraxial anesthetic, special attention should be given to the details of the technique, including baricity of local anesthetic, total dose and patient position. Furthermore, a catheter-based neuraxial technique should be considered as it can offer even better control over the extension of the block as compared to the single-injection technique.
This patient is on an NSAID. However, a recent Consensus Conference on Neuraxial Anesthesia and Anticoagulation78,83 concluded that NSAIDs appear to represent no added significant risk for the development of spinal hematoma in patients having epidural or spinal anesthesia.
39.6.3 Which Regional Anesthetic Technique Would Be Most Suitable for This Patient?
A better choice for this patient may be the performance of peripheral nerve block(s), if appropriate for the surgery. Peripheral nerve blocks used as a main mode of anesthesia for RA patients have been reported by many authors.84,85 Since the patient is scheduled for knee surgery, an anterior-approach femoral nerve block, combined with sciatic nerve block would be most appropriate. A local anesthetic mixture of mepivicaine 1.5% and ropivicaine 0.5%, using a total volume of 25 to 30 mL for each nerve block will provide superb anesthesia for a total knee replacement and possible tourniquet pain.86 Additional obturator and lateral femoral cutaneous nerve blocks may be required, depending on the patient's response. Although a lumbar plexus block could be considered, spinal deformities may make this approach more difficult and this block has a higher risk of complications, including those requiring emergency airway management. A catheter-based technique can also be used.