A case study on anesthesia management for thyroid surgery in patients with damaged lungs

The thyroid gland is an important endocrine organ of the human body. When pathological conditions such as thyroid mass, thyroid gland swelling, and hyperthyroidism occur, surgical treatment is often required. With the rapid development of anesthesia technology today, clinical thyroid surgery mostly uses general anesthesia with endotracheal intubation. This not only increases the comfort of the patient, but also provides greater convenience for the surgeon. But sometimes we also encounter some special patients who are not suitable for endotracheal intubation and general anesthesia for various reasons. At this time, we need to weigh the pros and cons and develop an individualized anesthesia plan to reduce the occurrence of related complications. Recently, the author's hospital received a patient with a thyroid tumor and damaged lung.

The patient, a 61-year-old female, was admitted to the surgical department due to a thyroid tumor and was scheduled for surgical treatment. The patient reported bronchiectasis, old tuberculosis for more than 30 years, long-term lung infection, cough, sputum, hemoptysis, and left lung damage. Complete preoperative related examinations: The patient's trachea was centered without deviation, the chest was symmetrical, and no breath sounds were heard in the left lung.

Chest CT showed: 1. Considered left-sided damaged lung; 2. Right lung cords; 3. Thickening of the left pleura with calcification; 4. Low-density shadow in the right lobe of the thyroid gland. Pulmonary function tests showed: decreased vital capacity; extremely severe mixed ventilation dysfunction; impaired small airway function; severely increased residual lung volume; increased pulmonary elastic resistance. Blood gas results in a calm state showed: PH 7.410, PCO2 41.0mmHg, PO2 98.0mmHg, and no obvious abnormalities were found in other laboratory tests. Preoperative diagnosis: 1. Bilateral thyroid tumors 2. Old pulmonary tuberculosis 3. Left-sided damaged lung, and it is planned to perform "substantially resection of the right lobe of the thyroid gland + resection of the left lobe tumor".

This case belongs to a patient with damaged lung secondary to pulmonary tuberculosis, often accompanied by symptoms such as coughing, sputum, hemoptysis, and dyspnea. Due to the long course of the disease, cavitation, fibrosis, and calcification occurred in the affected lung, leading to occlusion, stenosis, and deformation of the affected bronchus. Long-term repeated infections and increased secretions have led to irreversible destruction of the affected lung lobe. For such patients who require surgical treatment, they face difficulties in airway management during surgery, so the choice of anesthesia method and anesthetic drugs is particularly important. We conducted a detailed preoperative evaluation of the patient. After multidisciplinary consultation and communication with the patient and his family, we decided to abandon conventional endotracheal intubation and general anesthesia, and choose cervical plexus block anesthesia plus MAC (monitored anesthesia) to complete the operation, which is more conducive to the patient's rapid recovery after surgery.

The cervical plexus is composed of the anterior branches of the C1-C4 cervical nerves interwoven with each other. It is located outside the tip of the transverse process and deep to the sternocleidomastoid muscle, and gives off cortical and muscular branches (i.e., superficial and deep branches). The four cutaneous branches of the cervical plexus (the lesser occipital nerve, the greater auricular nerve, the transverse cervical nerve, and the supraclavicular nerve) pass through the cervical fascia at the midpoint of the posterior edge of the sternocleidomastoid muscle, and mainly control the skin sensation of the occipital region, auricle, neck, shoulder, and upper chest, and are pure sensory nerves. The deep branches of the cervical plexus generally control the levator scapulae, infrahyoid muscles, diaphragm, and deep neck muscles. Cervical plexus nerve block is to inject local anesthetics around the nerves so that the area it controls produces the corresponding anesthetic effect. It is worth noting that the deep cervical plexus block will inevitably block the phrenic nerve, which reminds us that even when bilateral thyroid surgery is performed, bilateral deep cervical plexus blocks cannot be performed to avoid breathing difficulties when the bilateral phrenic nerves are blocked at the same time.

After the patient entered the room, we first injected 2 mg of midazolam intravenously. After the patient's mood stabilized, we performed nerve blockade of the right deep cervical plexus and bilateral superficial cervical plexus under ultrasound guidance. About 15 minutes after the blockade, the patient's neck surface skin temperature, touch and pain were weakened. At the same time, we used sufentanil intravenous injection and dexmedetomidine hydrochloride continuous intravenous infusion during the operation to put the patient in a relatively ideal sedative state: the patient closed his eyes and was quiet, without obvious discomfort, while retaining spontaneous breathing, and the circulation was basically stable, and he could be awakened at any time to cooperate with the surgeon. After the operation, the patient woke up well and did not complain of obvious discomfort. At the follow-up visit 4 hours after the operation, the patient was fully awake, had no pain in the wound, had slight pulling pain when swallowing, and the VAS score was 2 points; at the follow-up visit 24 hours after the operation, the patient had no pain in the wound, the pulling sensation when swallowing was also reduced, and he could eat normally; at the follow-up visit on the 3rd day after the operation, the patient reported no discomfort; and was discharged 5 days after the operation.

The patient had poor lung function and a lot of secretions before the operation. Although conventional endotracheal intubation anesthesia can ensure the patient's comfort and safety during the operation, there is a high possibility of difficulty in extubation after the operation, which will inevitably prolong the patient's postoperative recovery period. The visual operation under ultrasound greatly improves the success rate of cervical plexus nerve block and can provide good analgesia for the surgical area. However, the pulling discomfort caused by the special surgical posture (extreme head tilt), the stuffiness of the surgical towel, and the patient's nervous fear, etc., require us to add appropriate amounts of sedatives and analgesics to relieve, that is, MAC (monitored anesthesia).

Isn't this the ERAS (Enhanced Recovery After Surgery) management that we are advocating now? Through a series of optimization measures, we formulate anesthesia plans that vary from person to person, and ensure the safety of patients, to achieve painlessness and comfort to the greatest extent possible, and to combine multiple disciplines to reduce the physiological and psychological trauma stress of surgical patients and achieve the goal of rapid recovery.

Li Yehua, Department of Anesthesiology, Shijiazhuang Ping An Hospital

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