3 | DISCUSSION
SWS is characterized by angiomas involving the brain, face, and eye. The rupture of angiomas may result in uncontrolled hemorrhage and may be fatal. Therefore, the rupture of angiomas should be avoided in anesthetic management.
In this case, mask ventilation was difficult because his upper lip was markedly swollen and protruded due to angiomas. Therefore, we checked mask fitting and prepared a large mask and total-face mask, which is often used for noninvasive positive pressure ventilation therapy. We could perform mask ventilation with a large mask. However, we needed to use an oral airway, which could cause pressure on the swollen upper lip. The pressure on the lip might cause the rupture of angiomas. Therefore, we changed to a total-face mask for mask ventilation. The total-face mask allowed us to perform mask ventilation without an oral airway and avoid pressure on the lip.
Generally, airway management is performed with nasal intubation in SSRO because surgeons should check the bite during surgery. However, in this case, the otolaryngologist suggested avoiding nasal intubation because of the angiomatosis in the nasal cavity and the remarkable bony thickening of the inferior nasal dorsum. In such a case, tracheostomy is an alternative option. However, tracheotomy is associated with various complications and should be avoided whenever possible.10 Thus, SMI is another option. SMI is an alternative to tracheotomy11 and has been used in patients with severe maxillofacial trauma. Although SMI was applied in orthognathic surgery, the application of SMI to patients with SWS has not been reported. SMI can cause complications such as superficial infection of the submental wound, orocutaneous fistula, abscess formation, and hypertrophic scarring. However, these complications are rare.12 Fortunately, no angiomas were found in the submental region by magnetic resonance imaging in this case. Therefore, we decided to perform airway management with SMI during surgery. When we pulled the ETT from the floor of the mouth, we placed a sterilized echo probe cover over the ETT to let it go through smoothly because we could not remove the connector of the wire-reinforced tube in our institution. This method helped mitigate bumps on the connector of the ETT to avoid tissue damage and infection and prevent blood from entering the ETT. Goh et al. reported that damage to the tube apparatus is one of the most common complications of SMI.13 This method also helped to avoid damage to the pilot balloon because the sterilized echo probe cover prevented it from directly gripping.
Blood pressure should be controlled to avoid the rupture of angiomas. Therefore, the depth of anesthesia was monitored using an entropy monitor. This is an electroencephalography-based monitor for determining hypnotic and analgesic levels. In this case, this monitor showed that state entropy (SE) and response entropy (RE) varied from 40 to 60 during anesthesia. The recommended range for adequate depth of anesthesia regarding each parameter (SE or RE) is 40–60.14Therefore, anesthetics appeared to be administered adequately, and the blood pressure was stable during surgery.
Maraña Pérez et al. reported that 46% of patients with SWS have mental retardation.15 Low cognitive understanding and intellectual disability can interfere with perioperative doctor-patient communication, which causes mental stress, elevated blood pressure, and swelling of angiomas.16 However, the patient’s intellectual disability was borderline, and no communication problems were noted. Therefore, we attempted to form a trusting relationship with the patient through several preliminary examinations and detailed explanations. Consequently, we did not prescribe premedication but lidocaine tape to reduce stress as much as possible. These might help maintain stable blood pressure.
Previous studies have reported that propofol can induce seizures in patients with poorly controlled epilepsy. Our patient had a history of epilepsy. However, he had no seizures for more than 10 years without medication. In addition, propofol has significant anticonvulsant effects and has been used to manage status epilepticus.3 Our patient also had a history of glaucoma. Therefore, we had to avoid raising intraocular pressure (IOP) during surgery because high IOP could damage the optic nerve and cause vision loss. Previous studies have reported that propofol attenuates increased intraocular pressure.17, 18 In addition, propofol has been used in patients with SWS. Therefore, we used propofol as an anesthetic in this case.