As we all know, sound is a wave phenomenon that is generated by the vibration of an object and propagated through a medium (air or solid, liquid) and finally perceived by the auditory organs of humans or animals. In the human body, our vocal organs mainly include the larynx and vocal cords, and if these two parts are damaged, it may cause us to lose our voice.
For anesthesiologists, the procedure under general anesthesia, especially when performing endotracheal intubation, is the site that happens to be the human vocal organ, which can lead to damage. Hoarseness is common after vocal organ injury, but some patients with severe injuries may even experience difficulty breathing or loss of voice.
Among the many possibilities, the most common is injury caused by endotracheal intubation. It mainly includes traumatic edema of the vocal cords, dislocation of the cricoarytenoid joint, acute laryngitis, and even direct injury to the vocal cords.
The reasons for these adverse results may be the unskilled operation of the anesthesiologist, the excessive selection of the model of the endotracheal tube, the patient's own difficult airway, etc. It is important to note that after the intubation is completed, the balloon inflated at the front end of the endotracheal tube can compress the vulnerable area of the recurrent laryngeal nerve about 1 cm at the lower edge of the vocal cord or the anterior branch of the recurrent laryngeal nerve behind the thyroid cartilage groove.
When the balloon is inflated too much or compressed for too long, causing damage or paralysis of the recurrent laryngeal nerve, the patient's voice loss during the recovery period may occur, or even permanent aphonia. Therefore, when performing tracheal intubation under general anesthesia, it is necessary to be slow and gentle to avoid the phenomenon of coarse tubes. Choose the appropriate endotracheal tube according to the patient's condition, and replace the tube in time if necessary. Before tracheal intubation, it is necessary to determine whether the muscle relaxant drug is effective to prevent unnecessary damage during the intubation process.
For patients whose preoperative evaluation may be difficult for airway, we should seek the help of a senior physician and operate under the guidance of an experienced physician. For patients who have undergone repeated endotracheal intubation due to difficulty in intubation, an appropriate amount of dexamethasone can be given prophylactically to prevent laryngeal edema after surgery. Of course, for some non-essential intubation surgeries, anesthesiologists may also choose to use a laryngeal mask for mechanical ventilation to reduce throat damage.
Safe and correct endotracheal intubation and reasonable intraoperative management are effective measures to avoid postoperative loss of voice. After the operation, we also need to determine whether the muscle relaxant drug is completely metabolized, if the muscle relaxant drug metabolism is not sufficient, the muscles of the vocal organ will be in a relaxed state, unable to contract, resulting in the patient not only unable to speak, but even dyspnea. Before the endotracheal intubation is removed, we can give the patient about 5ug of sufentanil, so that the patient can tolerate the endotracheal intubation, and make a simple judgment based on the amount of air exhaled by the patient and whether he can cooperate with some basic movements; Patients may also be given an appropriate amount of antagonists to counteract the effects of muscle relaxants. Of course, the anesthesiologist should have the endotracheal intubation apparatus at hand at all times, and in case of emergency, a second intubation should be performed.
For some patients who are overly nervous or have excessive mood swings during the perioperative period, hysterical aphonia may also occur after the operation, and the main reason for its occurrence is due to the patient's mental problems without organic injury. For patients with a history of hysteria, hysterical personality, and high fear before surgery, the anesthesiologist needs to have detailed, friendly communication to improve the patient's mood. Some sedative medications may be used if necessary to reduce the patient's nervousness. If hysterical aphonia is confirmed after surgery, psychological suggestion is used to improve the patient's mental state and build the patient's confidence.
Of course, for some special surgeries, such as thyroid surgery, otolaryngology surgery, cardiothoracic surgery, etc., due to their special surgical area, it is possible to directly damage the vocal cords or vagus nerve, resulting in the inability of patients to speak after surgery. After the patient has lost his voice, the anesthesiologist should communicate with the surgeon in time to confirm whether the injury is caused by the surgery to avoid more serious accidents.
For clinical general anesthesia surgery, effective prevention cannot completely eliminate the occurrence of postoperative aphonia. When we encounter a patient with aphonia after the operation, we should first ensure that the patient's airway is clear, the respiratory function is basically back to normal, and the patient's state of consciousness and vital signs are stable. Flexible bronchoscopy or electronic laryngoscope can be used to timely and accurately determine the possible causes of the patient's voice loss. For some mild aphonia (eg, hysterical aphonia, mild laryngeal edema), the patient can be admitted to the recovery room for observation while the patient is safe. However, some difficult-to-deal aphonias, such as dislocation of the cricoarytenoid joint, acute severe laryngeal edema, direct injury to the vocal cords and recurrent laryngeal nerve, etc., require anesthesiologists to contact the otolaryngology department for emergency consultation and treatment in time to prevent other more serious consequences.
Postoperative loss of voice can be extremely unsettling and even have serious effects on patients, which is a problem that every anesthesiologist should not ignore.
Li Chao, Department of Anesthesiology, Shijiazhuang Ping'an Hospital.
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