Management of Complications in Oral and Maxillofacial Surgery. Группа авторов

help to abolish the protective airway reflex and relax the vocal cords to allow the passage of air. Positive pressure ventilation, especially when instituted early in the course of the laryngospasm, is frequently successful at “breaking” the spasm. If it appears that secretions or bleeding in the oropharynx may be contributing factors, a brief period of suctioning with a tonsillar (Yankauer) suction may be helpful. Care should be taken that this does not delay positive pressure ventilation, however, and that the suction itself does not serve to further provoke the laryngospasm reflex. If neither deepening the anesthesia nor positive pressure ventilation proves successful, the treatment of choice for laryngospasm is the administration of the neuromuscular blocking agent succinylcholine. Succinylcholine for the treatment of laryngospasm is typically given at a dose of 20–40 mg initially, with an additional 20–30 mg given a minute or two later if the first dose proves insufficient [18]. This dose is less than the “standard intubating dose” of succinylcholine, but whenever a paralytic agent is given, it is safest to assume that complete paralysis may occur and the practitioner should be prepared to assist the patient's ventilation until the drug has adequately worn off and the patient is ventilating well without assistance.

       Aspiration

Aspiration refers to the entry of substances such as blood, saliva, gastric contents, or foreign bodies into the lungs via inadvertent inhalation. Aspiration occurs due to decreased or absent protective airway reflexes and is exacerbated by decreased gastroesophageal tone. Patients with neuromuscular degeneration or history of stroke are at increased risk as are those undergoing sedation and general anesthesia. Additional risk factors include gastroesophageal pathology such as GERD (gastroesophageal reflux disease), hiatal hernia, or achalasia, as well as a history of esophageal surgery or gastric bypass [19]. The greatest risk from aspiration occurs with aspiration of gastric contents. This can lead to acute respiratory distress syndrome or a chemical pneumonia causing damage to the lungs from the low pH of gastric fluids and the presence of peptic enzymes. Either passive regurgitation of stomach contents or active vomiting during anesthesia can lead to aspiration. Any patient who begins to retch or vomit during an anesthetic procedure should be placed with their head lowered (Trendelenburg positioning) to prevent aspiration into the lungs, and any vomitus should be suctioned carefully from the mouth and oropharynx. Patients known or suspected to have aspirated vomitus should have their respiratory status carefully monitored as they may require elective intubation with lavage and suctioning of the bronchial tree. The role of steroids and antibiotic therapy in these patients has been questioned and they are not routinely administered. In the absence of signs indicating respiratory compromise, management of aspiration is expectant.

      In the case of aspiration of a foreign body, the surgeon may make a careful attempt to visualize and retrieve the object if possible. A laryngoscope and MacGill forceps may be helpful in this situation. If the object cannot be visualized for removal, the patient's respiration should be monitored and supported as needed and the patient transferred to a hospital.

       Preoperative Fasting Period (NPO Guidelines)

      In order to decrease the risk of aspiration, a preoperative fasting period is typically required of patients undergoing an anesthetic procedure. The usual prohibition is nothing to eat or drink after midnight prior to the day of surgery, with the intent that a patient having surgery in the morning will have a completely empty stomach for the procedure. There has been some debate recently about the preoperative fasting guidelines in recognizing the need to make them as patient‐friendly as possible while also recognizing that due to individual differences in gastric emptying there may be situations where patients will not have a completely empty stomach despite adhering to the fasting guidelines. Currently, the ASA recommends “light” solid food up to six hours before and clear liquids two to three hours prior to undergoing anesthesia. The goal is to minimize the risk of aspiration due to a full stomach while at the same time avoiding dehydration and hypoglycemia from prolonged fasting. Diabetic patients may require individualized fasting guidelines because they are especially susceptible to hypoglycemia and may also have delayed gastric emptying due to gastroparesis. Young children are another group for whom special consideration may be necessary when prescribing preoperative fasting guidelines.

       Acute Vascular Events

      Acute vascular events are among the most serious perioperative complications and include myocardial ischemia, MI, and cerebrovascular accident (stroke). Due to the high prevalence of cardiovascular and atherosclerotic diseases in adults, complications of this nature should be anticipated in any office emergency plan.

      Myocardial ischemia and MI are most common in the postoperative period [16] and can be related to the surgical procedure, the anesthesia, or both. In a very anxious patient with a history of ischemic heart disease, the preoperative period presents a risk of acute angina. Risk factors for acute vascular events include history of heart disease or cerebrovascular disease, increasing length and invasiveness of surgery, and significant changes in heart rate, respiration, or blood pressure due to anesthetic drugs or surgical manipulation. Though profound fluctuations in heart rate, blood pressure, or respiration should be avoided in any patient, this is critical for individuals with underlying risk factors for acute coronary or cerebrovascular complications. In these patients, vital signs should be maintained close to baseline to avoid hemodynamic decompensation.

Acute angina is characterized by a sensation of pain, tightness, or crushing in the substernal region of the chest and may be accompanied by shortness of breath, anxiety, and diaphoresis. It can be difficult to differentiate acute angina from a panic attack or GERD/acute gastritis unless the patient has a history of angina episodes. Acute angina should be treated by discontinuing any stimulating procedure, administering a dose of sublingual nitroglycerin, applying supplemental oxygen via face mask or nasal cannula, and continuous monitoring of vital signs. (Because nitroglycerin can lower blood pressure, it should not be given if hypotension is present. Also, it is contraindicated in patients who have recently taken phosphodiesterase inhibitor medications such as sildenafil.) If the pain does not subside completely within 10 minutes, a second dose of nitroglycerin may be given. Up to three doses of nitroglycerin have been recommended to alleviate symptoms of angina, but the surgeon should take into account the patient's medical history and level of distress in deciding when to call EMS (emergency medical services). It is recommended that EMS be notified immediately and that emergency medical drugs and supplies be readily available (advanced cardiac life support [ACLS] protocol) in cases of moderate to severe chest pain lasting 30 minutes or more, when the pain appears to be getting worse, if two to three doses of nitroglycerin are not sufficient to provide relief, and in any patient who is hemodynamically unstable.

      In situations where a MI is suspected, the patient should be given 325 mg of aspirin (chewed or crushed is preferable as it speeds absorption of the drug), sublingual nitroglycerin, and supplemental oxygen. If morphine is available, this should be given as well, both for pain relief and because it causes peripheral vasodilation, which enhances cardiac output. The patient's vital signs should be monitored continuously until EMS arrives, particularly the ECG (arrhythmias may accompany myocardial ischemia and can signal imminent cardiac arrest) and blood pressure. If the patient deteriorates to a situation of cardiac arrest, the ACLS protocol should commence without delay. (NB: Adequate and uninterrupted chest compressions are now recognized as a key to successful resuscitation efforts. If the patient is in a dental chair without a hard, flat back or that does not recline completely, it is preferable to place the patient on the floor so that adequately forceful chest compressions can be delivered against a firm supporting surface.)

      The management of a patient where stroke/cerebrovascular accident is suspected includes notification of EMS and supportive measures. Supplemental oxygen should be given and the patient's vital signs monitored. A brief neurological examination may distinguish true cerebrovascular complications from confusion or disorientation that may result from anesthetic drugs. Aspirin should not be given to a patient suspected of suffering a stroke because intracerebral hemorrhage may be present. Patients who develop signs of neurocognitive deficit in the setting of severe hypertension (systolic >200 mmHg, diastolic >110 mmHg) should