Anesthetic Management of a Patient with Multinodular Goiter for Thyroidectomy: A Case Discussion
Patient Presentation and Clinical History
Who is the patient and what is her chief complaint?
The patient is a 30-year-old female, a housewife from Calicut.
Her chief complaint is a swelling in the front of her neck for the past 2 years.
What is the detailed history of the presenting illness?
She was apparently well 2 years ago when she noticed a swelling in the front of her neck.
The onset was insidious, initially noted on the right side.
It gradually increased in size and extended to the left side of the neck.
During the first year, she experienced loss of appetite, heat intolerance, tiredness, and tremors,
but these symptoms are now absent. There is no history of voice change, breathing difficulty,
or difficulty swallowing solids or liquids, and the swelling is not associated with pain.
The swelling moves with deglutition (swallowing).
Why were specific symptoms like loss of appetite and heat intolerance asked about?
The intention behind asking about symptoms like loss of appetite, heat intolerance, and tiredness
was to determine if the patient was hyperthyroid or hypothyroid.
The initial symptoms (loss of appetite, heat intolerance, tiredness, tremors) pointed towards a hyperthyroid state,
but the fact that they are now absent suggests it may have been controlled, possibly by medication.
What other symptoms were ruled out in the history?
The patient has no history of palpitations, sleep disturbances, lethargy, cold intolerance,
weight gain, constipation, irregular menstruation, diarrhea, dry skin, hair loss, or easy irritability.
What are the system-wise symptomatology for a hyperthyroid and a hypothyroid patient?
- Hyperthyroid Symptoms:
- General: Malaise, heat intolerance, sweating.
- CNS: Tremor, palpitations, anxiety, nervousness.
- Cardiovascular: Angina, breathlessness, palpitations.
- Genitourinary: Menorrhagia, loss of libido.
- Eye Signs: Exophthalmos (more common in hyperthyroid).
- Hypothyroid Symptoms:
- General: Cold intolerance, arthralgia, myalgia.
- CNS: Lethargy, malaise, muscle wasting.
- Cardiovascular: Bradycardia, features of decreased cardiac output.
- Genitourinary: Loss of libido, oligomenorrhea.
- Eye Signs: Usually no specific eye signs.
How is primary thyrotoxicosis distinguished from secondary thyrotoxicosis?
- Primary Thyrotoxicosis: The pathology is in the thyroid gland itself,
leading to increased production of thyroid hormones. Biochemically, there is increased T3 and T4
with suppressed TSH. CNS manifestations are more common.
Treatment involves anti-thyroid drugs or radioactive therapy.
- Secondary Thyrotoxicosis: Caused by excessive stimulation of the thyroid gland from outside,
such as in gestational thyrotoxicosis or a TSH-secreting pituitary adenoma.
Obstructive symptoms are more common. Surgery is often required for obstructive features.
What were the findings in the past, family, and personal history?
- Past History: No history of coronary artery disease, hypertension, diabetes,
previous surgeries, or radiation exposure.
- Family History: No similar illness in the family.
- Drug History: She has been taking Carbimazole 20 mg for the past 6 months.
- Personal History: Mixed diet, normal appetite and sleep, regular menstrual cycle, no addictions.
What were the general and airway examination findings?
- General Exam: Moderately built and nourished, height 160 cm, weight 50 kg, BMI 19.5 kg/m².
No facial dysmorphism, eye signs, or tremors. Skin and hair were normal.
- Vitals: Pulse 88/min, regular; BP 120/70 mmHg; RR 16/min.
- Airway Assessment: Mouth opening > 3 fingers, MPG Class II, Sternomental distance 13.5 cm,
neck movements normal, no loose teeth.
What were the findings on local examination of the neck?
- Inspection: A large swelling (approx. 8x5 cm) in the anterior neck, extending vertically from the lower thyroid cartilage to 1 cm above the suprasternal notch, and horizontally between the anterior borders of both sternocleidomastoid muscles. It moves with deglutition.
- Palpation: The swelling was firm in consistency with a nodular surface (multiple nodules).
It moved with deglutition and was not fixed to the skin. No bruit or thrill.
Pemberton's sign and Kocher's test (for thoracic inlet obstruction) were negative.
What is Kocher's test and what does it indicate?
Kocher's test involves pushing the lateral lobes of the thyroid. A positive test, where the patient experiences stridor,
indicates a retrosternal extension of the thyroid swelling causing thoracic inlet obstruction.
Pemberton's test is similar, asking the patient to elevate both hands, which may cause facial congestion and respiratory distress. In this patient, the test was negative.
What was the provisional diagnosis after the clinical examination?
The provisional diagnosis was Multinodular Goiter with Euthyroid status.
This was based on the presence of a large, nodular thyroid swelling without any pressure symptoms
and no current clinical features of thyroid dysfunction.
Pre-operative Evaluation and Optimization
How would you evaluate this patient pre-operatively for an elective thyroidectomy?
- Laboratory Investigations:
- Complete Blood Count: To check baseline hemoglobin and rule out infection or Carbimazole-induced agranulocytosis.
- Thyroid Function Test: To confirm euthyroid status (low TSH with raised FT3/FT4 would indicate hyperthyroidism).
- Renal Function Test and Random Blood Sugar: Hyperthyroid patients can have glucose intolerance.
- Serology for Hepatitis B, C, and HIV.
- Blood Grouping and Cross-matching.
- Imaging:
- X-ray Neck (AP and Lateral views): To look for tracheal deviation or compression.
If compression is >50%, a CT scan of the neck and thorax is needed to assess the extent and narrowest tracheal diameter,
which helps in selecting the correct size ETT.
- Other:
- Electrocardiogram (ECG): To check for baseline rhythm and any tachyarrhythmias.
- ENT Surgeon Consultation: For indirect laryngoscopy or fiberoptic scope to assess vocal cord mobility and document baseline function.
- Pulmonary Function Test with Flow Volume Loop: To objectively assess for any upper airway obstruction.
How would you prepare the patient on the day before surgery?
- Meet and Reassure the Patient: To alleviate anxiety and build rapport.
- Review Pre-anesthetic Check-up (PAC) Paperwork: Ensure all investigations are reviewed.
Advise the patient to take her usual Carbimazole tomorrow morning with sips of water.
- NPO Instructions: Advise NPO for solid food from 12:00 AM and for clear liquids from 6:00 AM on the day of surgery.
- Pre-medication: Consider prescribing an anti-anxiety agent like Alprazolam 0.25 mg to be taken the night before.
- Check for Symptoms: Ask about any symptoms of upper or lower respiratory tract infection.
- Check Vitals: Document baseline vitals (BP, Pulse, SpO2).
- Counseling: Counsel the patient and bystanders about the procedure and its complications.
Reassure the patient she will have a comfortable sleep and wake up after the surgery is over.
What preparations would you make in the operating room on the day of surgery?
- Environment: Maintain ambient temperature in the OT.
- Equipment Check: Check anesthesia machine, monitors, and suction apparatus.
- Airway Trolley: Prepare the intubating trolley with different sizes of face masks,
reinforced endotracheal tubes (Plan A: 7.0 mm ID reinforced ETT, with smaller sizes ready),
laryngoscope blades (size 3 and 4), and a difficult intubation trolley (with LMA, video laryngoscope, McCoy blade, gum elastic bougie, stylets).
- Drugs: Load all necessary drugs - premedication (Midazolam, Fentanyl), induction agents (Propofol),
muscle relaxants (Vecuronium), and emergency drugs (Atropine, Adrenaline).
- Anticipate Complications: Keep drugs ready for a thyroid storm: Beta-blockers (Esmolol IV, Propranolol),
anti-thyroid drugs (Carbimazole, PTU - though oral, can be given via Ryle's tube), Hydrocortisone, and Dexamethasone.
- Infusion Pumps: Arrange syringe pumps for infusions (e.g., Esmolol).
- Other: Check the OT table, arrange a DVT pump, and prepare for eye protection.
Intra-operative Anesthetic Management
Describe the induction and intubation plan.
- Shift patient to OT, secure 18G IV cannula, start Ringer's Lactate at 100 ml/hr.
- Attach standard monitors (NIBP, ECG, SpO2).
- Premedicate with Inj. Midazolam 1 mg and Inj. Fentanyl 100 mcg IV.
- Preoxygenate the patient for 3 minutes.
- Induce with titrated doses of Propofol until the patient is apneic.
- Confirm ability to bag-mask ventilate.
- Administer skeletal muscle relaxant, Inj. Vecuronium 5 mg IV.
- Ventilate for 3 minutes. Consider giving Inj. Esmolol to blunt the laryngoscopic response.
- Intubate with a 7.0 mm ID reinforced endotracheal tube. Fix the tube carefully to prevent accidental extubation due to positioning.
- Connect to the ventilator using a close circuit and maintain anesthesia with O2, Air, and Sevoflurane.
- Start Esmolol infusion (loading dose of 50 mcg/kg over 10 min, then maintenance at 10 mcg/kg/min, titrated to effect).
What is the role of hypotensive anesthesia or other measures to reduce blood loss?
Instead of hypotensive anesthesia, measures like proper positioning of the OT table to facilitate venous drainage by gravity
and the use of anti-fibrinolytic agents like Tranexamic acid can be employed to reduce blood loss in the surgical field.
What parameters would you monitor during the surgery?
Monitoring during surgery includes heart rate, blood pressure, SpO2, EtCO2, urine output, temperature,
neuromuscular monitoring, and assessment of the surgical field for blood loss.
Why is temperature monitoring especially important in this case?
Even in a biochemically euthyroid patient, there is a high index of suspicion for a possible thyroid storm.
Surgical handling of the thyroid tissue can release thyroid hormones into the circulation.
A rise in temperature can be an early indicator of a hyper-metabolic state like a thyroid storm.
How would you diagnose and manage a suspected intraoperative thyroid storm?
- Differential Diagnosis: Malignant Hyperthermia, Neuroleptic Malignant Syndrome, Pheochromocytoma.
- Signs: Hypertension, tachycardia, arrhythmias, flushing, raised EtCO2, and the soda lime canister becoming hot.
- Immediate Management:
- Ask the surgeon to stop the procedure.
- Increase FiO2 to 100%.
- Initiate active cooling (cooling blankets, cold saline IV, cold bladder wash).
- Administer drugs to decrease hormone production: Tab. Propylthiouracil 200-400 mg via Ryle's tube.
- Suppress sympathetic response: Inj. Esmolol or Inj. Propranolol.
- Give glucocorticoids: Inj. Hydrocortisone 100-200 mg or Inj. Dexamethasone 8 mg.
Why is it important to assess the surgical field during the procedure?
Assessing the surgical field helps to estimate blood loss and the quality of hemostasis.
It also allows communication with the surgeon regarding the state of the trachea, especially its wall strength,
after removal of a large goiter.
Post-operative Care and Extubation Strategy
How would you plan the extubation, considering the risk of tracheomalacia and vocal cord palsy?
- Communication with Surgeon: Before extubation, discuss the integrity of the trachea and recurrent laryngeal nerves with the surgeon.
- Cuff Leak Test: If tracheomalacia is suspected, perform a cuff leak test.
This can be done as the patient emerges from neuromuscular blockade.
Deflate the cuff and observe the difference between inspired and expired tidal volumes.
Absence of a leak may indicate tracheomalacia.
- Assess Vocal Cords: Use a video laryngoscope to visualize vocal cord movements as the patient emerges,
or immediately after extubation. This allows for documentation and assessment of any palsy.
- Decision:
- If cuff leak test is absent (suggesting tracheomalacia), plan for elective ventilation for 24-48 hours and re-evaluate.
- If bilateral abductor palsy is suspected, it's an emergency. Reintubation with a smaller tube may be necessary.
What are your concerns and monitoring priorities in the Post-Anesthesia Care Unit (PACU)?
- Analgesia: Administer a superficial cervical plexus block before extubation for post-op pain relief.
Give IV Paracetamol 1 gm.
- Monitoring: Continue monitoring BP, ECG, SpO2, and temperature. Monitor urine output.
- Respiratory Distress: Monitor closely for stridor, respiratory distress, or desaturation.
Keep a suture-cutting needle at the bedside to release a hematoma if it occurs and compresses the airway.
- NPO and Fluids: Keep patient NPO for 6 hours. Continue IV fluids (RL or NS) at 100 ml/hr. Provide O2 at 5 L/min via face mask.
- Drain Output: Monitor the surgical drain for any collection.
- Specific Complications: Watch for airway edema, new stridor, and vocal cord palsies,
especially bilateral partial abductor palsy which is an emergency requiring reintubation.
What is your plan if a cuff leak test indicates tracheomalacia?
If the cuff leak test indicates tracheomalacia, the plan is to electively ventilate the patient for 24-48 hours.
After this period, a trial of extubation can be given following re-evaluation.
A multi-disciplinary decision involving surgeons should be made, as a tracheostomy might be required.
Teaching Points and Discussion Summary
What were the key positive aspects of this case discussion?
- Structured Planning: The team showed a clear, step-by-step plan from pre-op evaluation to post-op care.
- Comprehensive Pre-op Workup: They presented investigations in a classified manner (blood tests, imaging, consults), mimicking real-life practice.
- Good Communication Skills: The approach to reassuring the patient without giving overly technical details was appropriate.
- Anticipation of Complications: They were prepared for intra-op thyroid storm and post-op airway issues.
What important points should candidates remember for similar cases?
- Justify Negatives: Always have a reason for asking about negative history points.
- Know Clinical Signs: Be prepared to discuss surgical signs (e.g., Pemberton's sign, Kocher's test) and eye signs of thyroid disease.
- Hypothyroid Concerns: For a hypothyroid patient, be ready to discuss concerns like delayed recovery and how to troubleshoot.
- Deliberate Endobronchial Intubation: During intubation, one can deliberately intubate the right main bronchus and then slowly withdraw while auscultating to ensure the tube tip is just above the carina, preventing accidental extubation when the neck is extended.
- Retrosternal Extension: Be prepared to alter the plan if there is retrosternal extension, including preparation for possible sternotomy and ECMO.