1. Case information
The patient, a 58-year-old female, 135cm, 39kg, was found to have a painless thyroid mass for more than 30 years, and the tumor has gradually increased recently. The patient has no fever or pain, the mass can move up and down with the swallowing action, no fear of heat, excessive sweating, irritability, no obvious palpitations, fatigue, insomnia, and dreaminess; No dyspnea after activity, no dysphagia, no hoarseness, no choking on drinking water.
Previous history of congenital spine and thoracic malformations, 50 years of tuberculosis. denial of history of hypertension, coronary heart disease, diabetes mellitus; Denial of cerebrovascular history. Denial of history of surgery and blood transfusion. Denial of a history of food and drug allergies.
Admission examination: T 36.4°C, P 112 times/min, R 21 times/min, BP 101/69mmHg, conscious, mental ability, autonomic position, physical examination cooperation, thoracic deformity, equal respiratory mobility in both lungs, no dry and wet rales in both lungs, heart rate 112 beats/min, regular cardiac rhythm, no murmur in each valve auscultation area, no edema in both lower limbs, normal muscle strength in the limbs.
Specialist examination: no jugular venous distension in the neck, soft neck, left tracheal compression, palpable mass on the right side of the anterior median cervical area, about 8cmx7cmx6cm in size, nodular surface with unclear borders, tough, no tenderness, up and down with swallowing action, and no palpable abnormality on the left side. No bruits were heard, and no significant lymphadenopathy was heard.
Preliminary diagnosis: 1. Goiter 2. Congenital thoracic deformity 3. Congenital spinal deformity 4. Old tuberculosis
Second, the results of the examination
1. ECG:
2. CT of the chest: chronic inflammation of the lower lobe of the right lung, bronchitis, thoracic deformity.
3. Pulmonary function: moderate to severe restrictive ventilatory dysfunction, small airway dysfunction, severe MVV reduction, moderate diffusion dysfunction.
4. There were no obvious abnormalities in liver and kidney function, blood analysis, coagulation function, thyroid function and troponin.
3. Anesthesia diagnosis and treatment process
1. Preoperative preparation
The patient had a huge thyroid mass, about 8cmx7cmx6cm, with a long medical history, narrowing and shifting of the squeezed airway, and CT showed that the maximum stenosis was 8.2mm at 32.6mm subglottic (communicating with the attending doctor found that the patient's tumor was a non-malignant tumor infiltrating airway invasion), and at the same time combined with spine, thoracic deformity and small jaw, there was a possibility of difficult airway.
The patient was visited in the ward 1 day before surgery, and the patient had a small lower jaw, mouth opening degree of 3 transverse fingers, Mallampati grade III, and neck range of motion was acceptable. The patient reported no symptoms of orthostatic compression of the trachea, no wheezing, shortness of breath, dyspnea, no dysphagia, and no hoarseness. Patients and their families are fully informed of the necessity and risks of anesthesia and the possibility of being sent to the ICU with an endotracheal tube after surgery.
After a systematic preoperative evaluation, it was determined that the greatest challenge in anesthesia for this procedure was the management of the difficult airway. The rapid induction of tracheal intubation commonly used in clinical practice needs to be carried out under general anesthesia, and the patient has no spontaneous breathing after the use of muscle relaxants, because the mass has been up to 30 years, the patient's trachea has been compressed for a long time, and the trachea will further collapse or even occlude after the use of muscle relaxants. Moreover, the patient's lung function is poor and his oxygen storage capacity is reduced. Therefore, the anesthesiology team developed a protocol for preoperative discussions to preserve spontaneously breathing awake intubation to create an artificial airway.
Before anesthesia, prepare airway tools such as video laryngoscope, flexible bronchoscope, supraglottic airway/core intubation tools, oropharyngeal nasopharyngeal airway [1], because CT showed that the strictest part of the subglottic was 8.2 mm, so the ID6.0# reinforced endotracheal tube (OD8.2 mm) was selected, and the 5.5# strengthened endotracheal tube was spared. At the same time, prepare rescue drugs such as atropine, ephedrine and related anesthetic drugs, and prepare suction devices, anesthesia machines, etc.
2. Anesthesia process
Inform the patient of the precautions for conscious endotracheal intubation, do a good job of explaining the patient, and try to strive for the patient's full cooperation.
After entering the room, intravenous access was established, ECG monitoring and mask oxygen inhalation of 5L/min, intravenous continuous pumping of dexmedetomidine 1ug/kg for 15min for full sedation, and dexamethasone 10 mg intravenous drip to prevent laryngeal edema. At the same time, the patient was given oropharyngeal epianesthesia with 2% lidocaine solution 100mg in the mouth for 3min, and then the epiglottis was provoked with a video laryngoscope and the laryngeal naress was used to perform surface anesthesia on the throat, glottis and trachea in stages, and the tracheal tube entered the glottis smoothly under the video laryngoscope, and the patient felt slightly uncomfortable when passing through the tracheal stenosis, and after communication, the tracheal tube entered gently and stopped at 21 cm of the catheter; The ventilator was connected, the end-tidal carbon dioxide waveform was good, the intubation was confirmed, and the intravenous anesthetic drugs were started: midazolam 2 mg, cis-atracurium besylate 10 mg, propofol 2 mg/kg, and sufentanil 20 ug.
术中维持：持续吸入七氟醚1.5%-2%，泵注丙泊酚100mg/h，切皮时舒芬太尼30 ug，iv。
Intraoperative infusion of 1500 ml of Ringer's solution, 500 ml of hydroxyethyl starch, and 200 ml of bleeding. The operation took 2.5 hours, and the vital signs were stable during the operation. After the tumor is removed, blood gases are performed and the results are generally normal.
After the operation, communicate with the surgeon and try to remove the endotracheal tube. After the patient was fully awake and spontaneously breathed back, the tracheal tube was successfully removed, and the patient was observed for 30 minutes, and the patient did not complain of obvious discomfort and was sent to the ward with An.
3. Postoperative follow-up
On the second day after surgery, the patient's vital signs were stable and there was no obvious discomfort. The patient was discharged after 7 days.
4. Discussion
The patient has been compressed by a thyroid mass for many years, has the possibility of tracheomalacia, and has congenital malformations and a small mandit, which may cause a difficult airway. For this patient, the most important thing is the induction of anesthesia and the establishment and protection of the airway. Establishment of an airway is important for both surgery and recovery. Airway management is the most important and dangerous aspect for anesthesiologists. The anesthesiologist should perform a preoperative evaluation to confirm the presence of a difficult airway.
1. Difficult airway judgment [2]
1) Observe the facial features of the patient: inability to open the mouth, protruding incisors, baldew teeth, huge tongue, micrognathia, short and thick neck, high larynx, extremely inflexible cervical spine, morbid obesity, etc.
2) Measure the opening degree: When opening the mouth as much as possible, the distance between the upper and lower incisors <3cm.
3) A-mental distance measurement: A-mental distance < 6 cm or the horizontal length of the mandible < 9 cm, indicating that intubation difficulties may occur.
4) Mallampantis test: This test is the most commonly used method in clinical practice and has high practicability. The observation of the hard and soft palate in the oral cavity is divided into 4 levels. Grade I is the soft palate, pharyngeal palatine arch, and uvula; grade II. indicates that the soft palate and pharyngeal palatine arch are visible, but the uvula is not visible covered by the tongue; Grade III is only visible to the soft palate; Grade IV is when only the hard palate can be seen. Grade III and IV may cause difficulty in intubation.
5) Check the nasal cavity: patients with poor ventilation and large nasal septum deviation, especially in the case of nasal endotracheal intubation, should be treated with caution.
6) Check the neck tilt: poor tilt, have suffered from cervical inflammation, fracture, dislocation and other diseases, or after fixation, neck stubby, huge tumor in front of the neck, excessive fat in the back of the neck, etc., will cause insufficient neck tilt.
7) Severe tracheal compression: If the patient has a huge anterior cervical tumor or hematoma, mediastinal tumor, etc., the tracheal compression can be severe due to tumor compression.
8) Know the history of airway: ask in detail about the patient's surgical history, trauma history, history of airway difficulties, whether there is tongue and epiglottis hypertrophy, sleep apnea syndrome, and other structural abnormalities.
9) Imaging examination [3]: X-ray images of the patient's neck and thoracic outlet, and the overlap of the oral, pharyngeal and laryngeal axes is simulated and analyzed on the X-ray film, and data reconstruction can also be carried out through CT and MRI to further observe the patient's detailed condition. In exceptional cases, ultrasound can be used to assess the extent of tracheal stenosis to aid in the selection of the endotracheal tube model and the depth of catheter insertion [4].
10) Laryngoscopy: the patient's exposure under laryngoscopy is graded, grade II or less indicates that intubation will be difficult, and grade I indicates that the vocal cords can be seen; Grade II. means only part of the vocal cords are visible; Grade III is only visible epiglottis; Grade IV is the inability to see the epiglottis.
The patient had congenital malformations and a small lower jaw, and the mouth opening and neck range of motion were acceptable. The diameter of the narrowed airway was measured in consultation with a radiologist before surgery, which provided guidance to the anesthesiologist in selecting the appropriate endotracheal tube model, but CT did not measure the length of the narrowed airway.
2. Selection of anesthesia induction method
Anesthesia induction methods are mainly divided into three categories: (1) rapid induction, in which the patient loses consciousness and respiratory depression during the induction process, which is suitable for patients at risk of aspiration, such as patients with full stomach, pregnant women, patients with intestinal obstruction, morbid obesity or symptomatic reflux; (2) Slow induction of amnesia analgesia, in which the patient is in a state of sedation, analgesia, and amnesia while retaining breathing, this slow induction method is widely used in ordinary difficult airways, which can allow patients to undergo surgery more comfortably and safely; and (3) awake endotracheal intubation to preserve consciousness, breathing, and memory, which is used only in special patients (risk of aspiration, anticipated difficulty of intubation, need to assess neurologic function after intubation or positioning) or when medication is contraindicated. The method of anesthesia induction in this patient is preferred for endotracheal intubation with sedation, wakefulness, topical anesthesia, and preservation of spontaneous breathing. Because the patient is able to maintain both spontaneous breathing and airway tone during awake endotracheal intubation, it has a high safety factor and is recognized as the gold standard for managing the expected difficult airway [5-10]. Adequate airway surface anesthesia is a very important prerequisite for the patient to undergo awake tracheal intubation, and appropriate sedation and analgesia before intubation and the patient's cooperation are extremely important. We had full communication with the patient before the operation and obtained good cooperation from the patient. Moreover, the patient's tumor was a non-malignant thyroid tumor that invaded the airway and had external pressure, and the possibility of puncture of the tumor tissue by tracheal intubation was small. The tumor has a certain elasticity, so the first endotracheal intubation can be successfully achieved;
In addition, the degree of tracheal stenosis directly determines the anesthesiologist's choice of endotracheal tube diameter. When the patient's tracheal stenosis ≤ 50%, the patient can be routinely intubated, and a normal or 0.5-1 small endotracheal tube can be used. When the patient's tracheal stenosis is > 50%, tracheostomy can be performed under local anesthesia if tracheostomy can be performed below the narrowing or obstruction of the airway; If tracheostomy is not feasible and the patient does not have symptoms of respiratory distress and severe carbon dioxide retention, endotracheal intubation is attempted with a jet ventilation device prepared and the cardiopulmonary bypass team on standby, and if the patient is accompanied by respiratory distress and severe carbon dioxide retention, cardiopulmonary bypass/extracorporeal membrane lung is established. In conclusion, the texture, extent of invasion, and degree of compression of the trachea have a great influence on the depth of endotracheal tube insertion, tube diameter, and choice of anesthetic method.
3. Awake intubation strategy
If the preoperative assessment is difficult to have an airway, the patient can have a video laryngoscope under adequate airway surface anesthesia, and repeated endotracheal intubation is contraindicated if awake endotracheal intubation cannot be completed because of the potential for laryngeal edema. Endotracheal intubation with video-flexible endoscopy increases the success rate of awake endotracheal intubation [1]. In addition, the flexible endoscopic intubation can observe the condition of the airway while entering, and at the same time, it can also complete the epiesthesia of the airway. In addition, when choosing awake oral intubation, nasal intubation is also prepared, and nasal intubation is closer to the airway, and the patient will be better tolerated.
In addition, cricothyroid membrane puncture is one of the first rescue methods used in clinical practice for patients with airway obstruction and severe dyspnea [11]. The cricothyroid membrane puncture technique can buy time for tracheostomy and is an important part of first aid in the first place. As long as the assessment is for a difficult airway, the anesthesiologist should locate the cricothyroid membrane (with ultrasound if necessary) and mark it with a marker once the patient enters the operating room. Emergency measures should be prepared well in advance of surgery, as temporary positioning of the cricothyroid membrane may waste valuable treatment time in an emergency.
4. Extubation strategy
Softening of the tracheal ring caused by long-term compression by a giant goiter is the most challenging problem faced by postoperative extubation, and prolonged airway compression and loss of support from surrounding tissues in the postoperative tracheal wall can lead to anteroposterior collapse, which in turn causes airway obstruction. Therefore, a good extubation strategy needs to be adequately developed preoperatively [5,12]. It is recommended to use a tube changer (a long plastic spring bar) to prevent tracheal collapse during extubation and to quickly re-intubate again in case of emergency. Some studies suggest that air leak testing can be used as an important indicator of the structure and function of the tracheal ring, but many clinical trials are still needed to support it [13]. Other related complications, such as wound oozing and compression of the airway, and hoarseness due to recurrent laryngeal nerve injury, also need to be closely monitored and treated.
In summary, anesthesia surgery in patients with giant goiter or mediastinal tumor compressing the trachea is still a serious challenge for anesthesiologists, and the implementation of comprehensive preoperative medical history, strict anesthesia protocol, intraoperative dynamic vital sign monitoring, and postoperative extubation timing are all crucial to the prognosis of patients.
Case-related imaging data:
References
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Song Yongxia, Department of Anesthesiology, Guanxian People's Hospital, Liaocheng City, Shandong Province
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