What factors are related to sore throat after general anesthesia? How to prevent it?

Throat pain after general anesthesia seriously affects the quality of anesthesia. At the same time, it also increases the difficulty of postoperative analgesia. In addition, it will also affect the patient's satisfaction with the anesthesiologist.

In clinical work, everyone is trying to avoid the occurrence of sore throat after general anesthesia. However, it is difficult and impossible to fully grasp the factors causing sore throat after general anesthesia. Below, we summarize the factors causing sore throat after general anesthesia:

First, there are surgical factors.

If the surgery is done on the head and neck, the incidence of postoperative sore throat is higher than that on surgeries in other parts of the body.

Second, the duration of the operation.

Studies have shown that the duration of tube wearing is related to the occurrence of sore throat after general anesthesia. One study showed that the incidence of sore throat and blood in sputum within 24 hours after removal of the endotracheal tube was lower when the tube was worn for ≤180 minutes than when the tube was worn for >180 minutes.

Again, it's about endotracheal intubation.

Among the factors related to endotracheal intubation, the material of the endotracheal tube, tube diameter, cuff pressure, cuff duration, and the method of endotracheal tube placement are related.

Regarding the material of the endotracheal tube, a study found that the incidence of sore throat was higher in the polyvinyl chloride endotracheal tube group than in the silicone endotracheal tube group 1 hour and 24 hours after endotracheal tube extubation.

The incidence of postoperative sore throat with single-lumen and double-lumen catheters is also different. Because double-lumen tubes are thicker and harder than ordinary tubes, and can be inserted deeper, and double-lumen tubes need to be repeatedly adjusted after intubation, which causes greater damage to the tracheal mucosa, the incidence of post-anesthesia sore throat after intubation with double-lumen tubes is higher than that with single-lumen tubes, and sore throat occurs earlier.

This also reminds us that choosing a catheter that is too thick can also cause sore throat after general anesthesia.

Cuff pressure has been a research hotspot in recent years.

Studies have shown that the endotracheal tube cuff pressure is proportional to the damage to the tracheal mucosa. There are also reports that when the cuff pressure is greater than 30cmH2O, the perfusion of the local tracheal mucosa is significantly reduced, causing ischemic damage to the local mucosa and submucosal tissue, leading to complications such as sore throat, hoarseness, and dysphonia.

Repeated intubation is also an important factor leading to sore throat after general anesthesia. Therefore, improving intubation technology is an effective means to prevent sore throat after general anesthesia.

In order to avoid repeated intubation, it is important to choose the appropriate catheterization method.

Studies have shown that during the intubation process, the video laryngoscope can observe the throat structure through the display screen, thereby clearly revealing the glottis and significantly reducing stimulation to the tongue root and throat tissues, which is of great application significance in reducing the incidence of postoperative throat pain.

Finally, one detail of general anesthesia operation is also worthy of attention, namely the suction operation.

Although many experienced anesthesiologists can reduce sputum secretion and eliminate the need for suction by accurately controlling the depth of anesthesia and using anticholinergic drugs, suction is still a common operation during general anesthesia.

Suctioning is an external stimulus to patients. If it is performed improperly or too frequently, it will cause unnecessary damage to the tracheal mucosa, and even aggravate hypoxemia and acute left heart failure, and even endanger the patient's life.

Since sore throat after general anesthesia is a complication that cannot be ignored, how can we prevent it from happening?

In addition to the above-mentioned complications that need to be paid attention to, there are also some measures to prevent their occurrence. For example, the use of local anesthetics, glucocorticoids, nonsteroidal anti-inflammatory analgesics, ketamine, dexmedetomidine and other drugs can effectively reduce the incidence of pharyngitis after general anesthesia.

Here we focus on the use of local anesthetics:

1. Lidocaine

Before intubation, lidocaine is injected intravenously or compound lidocaine syrup is applied topically. It can be applied to the cuff and front end of the endotracheal tube before induction of general anesthesia to prevent and treat post-anesthesia sore throat.

2. Tetracaine

Applying tetracaine glue to the cuff of the endotracheal tube before endotracheal intubation can reduce the strong stimulation of the endotracheal tube to the throat and trachea during endotracheal intubation, and alleviate hoarseness and throat pain after extubation.

However, it should be noted that tetracaine has a relatively high lipid solubility, strong permeability, and binds quickly and firmly to nerve tissue. It is highly toxic and there have been reports of allergic reactions and fatal reactions.

Finally, if you have any successful experience in reducing sore throat after general anesthesia, you are welcome to leave a message below to share~

Deng Qijuan, Department of Anesthesiology, Langzhong People's Hospital, Sichuan

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