Learning from Experience – Intra Operative, Chapters 9 and 10

INTRA-OPERATIVE

Chapter 9

Carotid blowout

Dr. Vasanthi Vidyasagaran*

Department of Anaesthesiology, Kauvery Hospital, Chennai, Tamilnadu, India

A 75-year-old man was admitted in the emergency for a swelling on the left side of his neck which was expanding rapidly. He had undergone carotid endarterectomy 15 days ago. During his previous procedure, his intraoperative and postoperative period had been uneventful and he was discharged on the 5th day.

Presently he gave a history of having a fish bone stuck in his throat which he tried to remove manually. This led to an episode of violent cough which had initiated the swelling.

The vascular surgeon who saw the patient immediately compressed the carotid and shifted him to the theatre.

On examination, patient was conscious, very pale, anxious, and gasping. Two large bore IV lines (16G) were started on both hands and fluids were rushed and blood was called for. Urinary catheter was already in place and monitors were attached. His PR = 143/min, and BP = 76/35 mm Hg.

As he was gasping, no IV or inhalational anaesthetic agent or muscle relaxant was used. Awake intubation was performed supplemented with Fentanyl 50 mcg and Midazolam 1 mg. Atracurium 25 mg was given after intubation and he was ventilated with Nitrous Oxide and Oxygen 50%.

As the procedure started, he crashed. CPR was given for 1 min. His rhythm reverted. Dopamine 8 mcg/kg infusion was started. Meanwhile, haemostasis was achieved. His BP picked up to 90/50 mm Hg, with pulse rate of 120/min. Four units of PRBCs and two FFP were transfused. Peripheries were still cold, Sao2 was 94%. In the meantime, blood was sent for ABG analysis, and the results were within acceptable limits.

He was ventilated for nearly 3 hours for complete recovery to assess the neurological status. Elective ventilation in the ICU was contemplated, but the patient regained consciousness, responded to commands and moved all 4 limbs. As his recovery was good, it was decided to extubate him on the table.

Discussion

In this scenario, we had a hemodynamically compromised elderly patient, with impending cardiac arrest, for emergency surgery. Even a little delay could have resulted in death of the patient. Good coordination between surgical and anaesthetic team is vital. Help from paramedical team and other units like the blood bank is crucial.

Definite airway must be secured early. There may not be time even for bag mask ventilation, first attempt is the best attempt. Timely intervention from all aspects like securing the airway, transfusion, ACLS and surgical skill saved our patient.

Carotid artery surgery, particularly with ruptured artery, carries high risk of neurological morbidity and death. Patients coming up for primary carotid surgery/endovascular management usually have multiple significant comorbidities, also have good collateral circulation. Most often they are performed under regional anaesthesia.

Anaesthetic implications in patients for carotid endarterectomy (CEA):

1. CEA is usually a prophylactic surgery. When it is bilateral chances of CVA is high.
2. Always associated with comorbidities
3. Two significant post-operative complications include cerebrovascular event and coronary event. Other complications may be cranial nerve injury, bleeding, and airway compromise due to hematoma and oedema,and vocal cord palsy
4. Procedure can be done under regional or general anaesthesia.

Regional anaesthesia options include superficial cervical plexus block, combined superficial and deep cervical plexus block, or cervical epidural. Local infiltration anaesthesia supplementation may be required. Carotid shunt may be used by the surgeons to facilitate cerebral circulation to bypass the area of artery repaired. It is imperative to maintain adequate cerebral perfusion pressure at all points of time. Anticoagulation must be commenced before cross clamping

General anaesthesia, if given is usually intubation and controlled ventilation.

Monitoring required in addition to standard monitoring include neuro monitoring (EEG/ SSEP/ NIRS and transcranial Doppler), intra-arterial blood pressure monitoring as there may be huge swings in blood pressure.
Central venous access may be necessary to commence vasoactive drugs

Anaesthetic goals

Maintain adequate optimal cerebral perfusion pressure
Maintain haemoglobin levels ≥ 10 g/dl
Beware of hazards of massive transfusion and overload
Once haemostasis is achieved and surgery is completed, plan for extubation if the procedure is done under GA.

Criteria for extubation

Hemodynamically stable patient with good rhythmic respiratory effort
Patient should not have suffered a significant cerebrovascular or cardiovascular event.
An alert patient able to cooperate for neurological testing at end of surgery

Smooth extubation with use of agents like Dexmedetomidine, with control of blood pressure is ideal.

Postoperatively patient may require monitoring in high dependency unit, with close watch for any cerebrovascular embolic events. Appropriate anticoagulation must be commenced from intraoperative period and continued into postoperative period.

Significant number of case reports of carotid blowout has been identified in literature. At risk patients include:

Head and Neck oncology patients, immediate post-operative period, post radiation
Blunt injury neck, involving trauma to vascular structures as well as nearby vital structures such as larynx, trachea, when securing the airway will be difficult
Poly trauma patients, with neck trauma and associated head and spine injury

Securing airway and maintaining oxygenation and ventilation are key factors for successful management of patient. Tracheostomy may be difficult or rather impossible due to altered anatomy/neck hematoma. Patients may be systemically compromised and positioning for tracheostomy will be difficult due to associated injuries.

References

Jarvik JG, et al. Penetrating neck trauma: sensitivity of clinical examination and cost-effectiveness of angiography. AJNR Am J Neuroradiol. 1995;16:647-54.
Sclafani SJ, et al. Internal carotid artery gunshot wounds. J Trauma. 1996;40(5):751-7.
Tisherman SA, et al. Clinical practice guideline: penetrating zone II neck trauma. J Trauma. 2008;64(5):1392-405.
Mattox K, et al. Penetrating and blunt neck trauma. Trauma. 4th ed. Appleton and Lange; 1999. 437-50.
Demetriades D, et al. Penetrating injuries of the neck in patients in stable condition. Physical examination, angiography, or color flow Doppler imaging. Arch Surg. 1995;130(9):971-5.

Chapter 10

Catastrophic manifestation of an unexpected hypothyroidism

A 40-year-old woman weighing 80 kg was posted for a hysteroscopy, curettage and cervical biopsy. Since it was a minor surgery, it was booked as a day care procedure. She was examined on the morning of surgery, all vitals were found to be normal. HR, 56/min; BP,110/70 mm Hg; and lungs clear. Basic blood investigations were normal. Airway was of MPC grade II. Plan was to perform the procedure under general anaesthesia.

She was induced with Thiopentone 250 mg and Fentanyl 100 mcg. It was noticed that her rate slowed down to 40/min. She was oxygenated and Inj. Atropine 0.6 mg was given immediately. However, there was no response and the rate slowed down further to asystole and she stopped breathing. She had a cardiac arrest. Cardiopulmonary resuscitation was started immediately.

Patient was intubated and ventilated with 100% oxygen, and chest compressions were given. ACLS protocol was followed. Only after about 15 minutes of cardiopulmonary resuscitation, there was return of spontaneous circulation, and rhythm compatible with life. The patient recovered with attempts at breathing. However, she was not fully conscious and the surgery was deferred. She was shifted to intensive care unit, where supportive measures were undertaken with vasopressors and ventilation.

Complete investigations were done in ICU. Thyroid function tests revealed greatly elevated TSH of 50 U/ml. All other blood investigations were within normal limits. Chest x-ray was clear. ECG showed sinus bradycardia (40 beats/min), with prolonged QTc interval. Echocardiogram revealed normal left ventricular function. No regional wall motion abnormality was found. Consciousness level assessed on day two was good whilst off sedation. Vasopressor support, and ventilation were gradually weaned down by day 3, and she was extubated.

This was a case of severe hypothyroidism which had predisposed to increased susceptibility at induction in a dramatic manner. Other causes that might lead to sudden cardiac arrest during induction of anaesthesia in an otherwise healthy person are drug related anaphylaxis and air embolism. Pre-existing causes such as hypoadrenalism and neuro and cardiac pathology are at times not picked in the pre- operative check, and these may also contribute to the abnormal response of a patient on induction. She was treated with IV T3 and corticosteroids to augment recovery. Patient recovered well and was discharged home on Eltroxin supplements.

Discussion

Sudden cardiac arrest during induction of anaesthesia in a patient who is considered healthy and suitable for day-care can come as an unpleasant shock to the anaesthetist.

Issues that come to focus here are:

1. Investigations in a day care setting is it acceptable to exempt from having investigations particularly in Indian setup where the patients do not go to hospital unless they are symptomatic?

a routine thyroid function testing for all surgical procedures may be considered.

1. Preoperative evaluation should be done for every case no matter however minor the surgery may be. Attention to detail during history taking and examination is a must. Importance of history elicitation is highly underestimated.
2. Importance of early recognition of problem and immediate action
3. Susceptibility to negative chronotropic effects of anaesthetic drugs in hypothyroidism, and sluggish or complete lack of response to resuscitative measures.

Hypothyroidism can have variable systemic manifestations including cardiac structural, functional and conduction defects. Knowledge of these effects of hypothyroidism on the heart is necessary for prompt treatment of patients with life-threatening complications as seen in our patient. Recovery with good prognosis is possible with appropriate timely treatment, however their response is sluggish compared to a normal patient. Bradycardia, low voltage, and heart block are the more commonly described effects, while sustained life-threatening ventricular arrhythmias may rarely be seen.

References

Klein I, Danzi S. Thyroid disease and the heart. Circulation 2007;116:1725-35.
Schenck JB, Rizvi AA, Lin T. Severe primary hypothyroidism manifesting with torsades de pointes. Am J Med Sci. 2006;331:154-6.
Shojaie M, Eshraghia A. Primary hypothyroidism presenting with torsades de pointes type tachycardia: a case report. Cases J. 2008;1:298.
Vasundhara M, Bhatta L. Sudden cardiac death due to untreated hypothyroidism. J Innov Card Rhythm Manag. 4(2013):1097-9.
Meyler’s Side Effects of Analgesics and Anti-inflammatory Drugs. Edited By Jeffrey K. Aronson. Elsevier 2010;137-8.

Record keeping and documentation is an important aspects of safe anaesthesia practice which is often overlooked, and amounts to negligence.

Learning from Experience – Intra Operative, Chapters 9 and 10

INTRA-OPERATIVE

Chapter 9

Discussion

Anaesthetic goals

Criteria for extubation

References

Chapter 10

Catastrophic manifestation of an unexpected hypothyroidism

Discussion

References

Journals