Nasal intubation is usually performed with a nasal RAE tube. The tube is then extended with a flexible “goose neck” connector, which is placed caudally over the forehead and hooked up to the anesthesia circuit using extension tubing. In order to minimize the risk of bleeding, sympathomimetic nasal drops can be used in both nares. The tip of the nose is in danger of developing pressure necrosis from the tube fixation. Therefore, one must take care that the tube fixation is free of tension.

Sometimes, a leaky cuff occurs after intubation, usually due to cuff damage from anatomical structures or the Magill forceps. No pressure should be placed on the cuff when using the Magill forceps. The cuff integrity must be carefully assessed after intubation, due to the limited airway access during surgery (see below).

Intraoperatively, the rule is “No Airway Access”. Therefore, it is necessary to secure the tube and its connection to the anesthesia circuit tubing very well.

Fixation of the tube can be done by taping or – with permission from the surgeon – by suturing, to the side of the nose. A special problem is intraoperative tube damage by the surgical instruments. This situation must be anticipated, with the required instruments ready for use – such as a Cook airway exchange catheter. At the end of the procedure, removal of the sterile drapes must be done carefully, to assure that accidental extubation does not occur.

The patients’ eyes are not accessible after the surgical area is draped. The anesthesia team must therefore protect the eyes from prep solution or pressure. You should discuss how to protect the eyes with the surgical team.

During surgery, the patients are positioned supine, slightly lateral, with the head hyperextended. Cerebral blood flow can be compromised in patients with arteriosclerosis of the carotid arteries.

At the start of the procedure, the surgeons tamponade the oropharynx. It is the anesthesiologist’s job to make sure that the throat pack is removed before the jaw is immobilized and before emergence from anesthesia.

Postoperatively, the jaw is immobilized by metal wires. Postoperative fixation requires the placement of the nasogastric tube, which, if all goes well, will not be used postoperatively. The anesthesiologist must know at which level (between which teeth) the intermaxillary fixation was done, in order to be prepared for an emergency. Should an emergency arise, requiring immediate severing of the fixation, wire cutters must be at the bedside, until the time at which the fixation is removed. In many cases, the surgeons use rubber bands for fixation in the immediate postoperative period, replacing the bands with wires once the patient has fully recovered from anesthesia. While rubber bands are easier to cut in the event of an emergency, the anesthetic implications are still the same.

After the osteotomy, the OMS surgeons use miniplates with tiny screws to create a new osteosynthesis of the mandible/maxilla. These screws withstand significantly less force than the intermaxillary fixation – at least when the fixation is done with wire. Forced mouth opening dislocates the screws, and patients have to understand in advance that they must not open their mouth and should breathe primarily through their nose. Therefore, patients’ need to have a high level of cooperation, which is influenced by the preoperative informed consent discussion and by the choice of medication (see below).

Furthermore, it has proven to be beneficial for the surgeon to stay in the OR until tracheal extubation. In case of emergency, the surgeon can cut the intermaxillary fixation the fastest and should hold the lower jaw until extubation is complete, which, at the least, would remind the patient not to open the mouth.

The goal of anesthesia for OMS is to have the patients as awake and cooperative as possible at the end of surgery and to avoid PONV (postoperative nausea and vomiting). Total intravenous anesthesia (TIVA) with propofol and remifentanil is an excellent choice to achieve these goals. The prophylactic administration of an antiemetic – for example, dexamethasone at induction of anesthesia or ondansetron prior to emergence – is beneficial (see Chap. 4 Table 4.​1). The postoperative analgesia should primarily consist of non-opioid analgesics, in order to reduce the risk of PONV.

Significant blood loss is to be expected with many maxillofacial procedures, such as Le Fort osteotomy or maxillary advancements. Possible strategies to reduce blood loss include the administration of tranexamic acid [2] and maintaining deliberate hypotension [3]. Whether or not these procedures lead to a reduction of blood transfusion is debated. Therefore, the indication should be carefully considered according to a risk–benefit analysis. In the presented case, the planned prognathism operation rarely has blood loss of more than 300 ml, making special considerations unnecessary.

In many hospitals, dexamethasone 10 mg IV is given just prior to starting surgery in order to reduce the inflammatory response, thereby reducing the local swelling. Effectiveness, however, is highly debated. Studies which show a shorter hospital stay after maxillofacial surgery with steroid administration often neglect to take into account the weakened immune defense and the danger of prolonged wound healing [4].

>> The induction and maintenance of anesthesia proceeded without incident. Dr. Greg carried out the anesthesia as “TIVA with propofol and remifentanil.” Muscle relaxation was only necessary to facilitate tracheal intubation with a nasal RAE tube (6.5 mm ID). After about 2 h, the maxilla and mandible were wired together to achieve immobilization.

Dr. Greg was accustomed to the problems of intermaxillary fixation and had the OR tech give him wire cutters for the patient. “Extubation only when full consciousness has been obtained, AND sufficient spontaneous respiration, AND adequate communication!” the attending anesthesiologist Dr. Eldridge had reminded him before surgery. “Any and all pharmacological excess (hypnotics, opioids, and muscle relaxants) must be avoided. Half an hour before the end of the operation, give a little bit of a longer working opioid, such as fentanyl, and combine it with a peripheral–acting analgesic such as acetaminophen or ibuprofen. The patient should receive substantial postoperative pain relief.”

Dr. Greg informed his attending Dr. Eldridge that he was ready to begin the emergence. The surgeon was present, in order to quickly and properly cut the wires, if needed. Dr. Greg suctioned the stomach through the nasogastric tube before extubation. Then Dr. Greg slowly removed the tube, all the while suctioning through the tube and finally suctioning the oral cavity.

Linda was really awake after the extubation. She denied pain or nausea. “I did it,” she thought. “What will my new chin look like?”

With cardiovascular stability and an SpO ₂ reading of 95 % on room air, she was transferred to the PACU. Dr. Greg informed the less experienced (second–year) PACU resident, Dr. Niac, about Linda: “She is a young, healthy patient. She had a mandibular prognathism osteotomy, and her jaw is now wired shut. The surgery and anesthesia went without complications, with a total blood loss of 300 ml. She received 1,500 ml of a Lactated Ringer’s solution. The emergency scissors to cut the wires are beside her on the bed. Linda was quite nervous before the operation, but now everything is OK.”

“Wow!” thought Dr. Niac. “A young healthy female, so rare here. I haven’t yet cared for a patient who is wired shut, but I won’t have any problems with her. She’s super healthy, which is good, since we are so busy.” Nevertheless, he quickly went to Linda’s bedside to form a better picture of the patient. The PACU nurse Maria was just hooking her up to the monitor, which showed:

Linda was shivering slightly and responded slowly, but adequately, to verbal stimuli.

A stress response is possible, due to pain, nausea, discomfort from a urine catheter or a full bladder, fear, or other psychological impairments, such as perioperative cerebral dysfunction (see Sect. 18.​1.​2).

Compensatory tachycardia can be triggered by hypovolemia or anemia and can – when the disorders are minimal – appear with hypertension.

Another possible reason for hypertension and tachycardia in the PACU is respiratory disorders, especially when hypoxia and/or hypercapnia are present. In the presented case, the low S_pO₂ value is a clue that there is a respiratory disorder.

Simultaneous appearance of muscle shivering, also called postoperative shivering, occurs in up to 50 % of all postoperative patients. It is a generalized, reflexive, non-suppressible tremor, which increases the production of energy by 50–100 %. The threshold for shivering is about 1 °C below the threshold for vasoconstriction as protection against hypothermia.

All anesthetic agents tested thus far affect autonomic temperature regulation [8].

Usually, there is an extension of the temperature range encompassing temperatures sensed as normal, so that the patients begin to sweat at higher temperatures and begin to feel cold at colder temperatures.