POST OPERATIVE Chapters 11 and 12 – Learning from Experience

Dr. Vasanthi Vidyasagaran*

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

*Correspondence: [email protected]

Dr. Vasanthy Vidyasagaran Muralidharan

POST-OPERATIVE Chapter 11

Hypercalcemia in Malignancy

A 35-year-old woman, one year postnatal, lactating until 3 months ago was posted for radical mastectomy for carcinoma breast. She had had three cycles of chemotherapy prior to surgery. On examination, she was reasonably fit for anaesthesia, haemoglobin 12 g/dl, all other investigations including white cell count were normal. She was taken up for surgery under general anaesthesia.

Intraoperative period was uneventful. She lost 400 ml blood, received 500 ml colloid and 1000 ml of crystalloids over two hours. She recovered without any problem and was shifted to postoperative ward. Unexpectedly, soon afterwards she had difficulty in breathing and was getting restless. Saturations began to drop to 94% on high flow oxygen. Auscultation of chest revealed mild basal crepitations. She was hemodynamically stable.

Drains were checked, no undue blood loss was identified. Congestive cardiac failure was thought of, possibly due to cardiotoxicity following chemotherapy. The fluids administered were also considered slightly in excess for the procedure. Injection Lasix 20 mg was given intravenously. She appeared to respond a little, saturation began improving to about 95-96%, but became restless again and complained of headache and severe muscle pain.

She was given IV Tramadol and Midazolam. Oxygen was continued through a face mask. Her respiratory efforts were good and she was fully conscious. In the meantime, a blood sample was sent to check for electrolytes sodium, potassium, calcium and magnesium and liver function tests. Results showed high serum calcium level of 14.5. Parathormone levels were also checked at this stage and it was also found to be high. She was admitted to the intensive care unit for further management.

Discussion :

The relationship of hypercalcemia with cancer is well described in literature. Breast cancer is the commonest malignancy associated with hypercalcemia. The detection of hypercalcemia in these patients usually signifies metastatic disease and may be associated with a poor prognosis.

Manifestation of hypercalcemia may vary from no symptoms to severe obtundation and even coma. When it is a chronic increase in calcium levels and less than 12mg/dl no treatment is required. When there is an acute rise or serum calcium levels or values more than 14mg/dl-treatment should be commenced without delay.

Such a presentation is quite rare, and this case highlights the importance of checking serum calcium levels in patients with malignancy. While most commonly associated with breast carcinoma, it has also been reported with thyroid, pancreatic, and lympho proliferative malignancies. Identification may be tricky, and the diagnosis in this patient was also by chance. In patients with parathyroid adenoma, removal of adenoma is the treatment of choice.

Hypercalcemia management includes:

  • Adequate hydration with saline (if ) but at the same time not to overload
  • Minimal sedation
  • Moderate doses of Frusemide
  • Management of nausea and vomiting
  • Bisphonates -intravenous Pamidronate, Zoledornic acid
  • Encourage mobility and provide analgesia
  • Calcitonin 4iu/kg IM or SC
  • Haemodialysis in rare
  • Reduce dietary Vitamin D

References

  1. Stewart Clinical practice. Hypercalcemia associated with cancer. N Engl J Med 2005; 352:373
  2. Strodel WE, Thompson NW, Eckhauser FE, Knol Malignancy and concomitant primary hyperparathyroidism. J Surg Oncol 1988; 37:10.
  3. UpToDate-treatment of hypercalcemia

POST-OPERATIVE Chapter 12

Hypocalcaemia following Non-Thyroid Surgery

Case 1: Carpopedal spasm

A 35-year-old man, was admitted for septoplasty as a day care procedure. It was planned to carry out the procedure under local anaesthesia. An intravenous line was placed and surgery was started under local analgesia. The anaesthetist was not called. During surgery, the patient became restless. He was reassured and instructed to concentrate on breathing and take deep breaths by the surgeon. The surgery continued for another 45 minutes.

Gradually, the patient became dyspnoeic and started gasping for breath. The pulse oximeter revealed oxygen saturation of 87%. PR=130/min and patient was getting agitated, and the breathing was noisy. Surgeon was concerned that it might be due to the local anaesthesia toxicity. (this was the history given by the surgeon.)

The anaesthesiologist was called for urgently! Initial observations revealed:

  • Patient hyperventilating at the rate of 25 breaths/minute and taking deep breaths on the instructions from the surgeon!
  • Saturation was 87%, PR=130/min, BP=160/100 mm Hg
  • There was noisy respiration probably due to laryngospasm
  • Tetany in both hands
  • ECG showed flattened T wave, bradycardia and 1st degree Atrioventricular block

The anaesthesiologist quickly reassured the patient and gave him 1 mg Midazolam. Surgery was abandoned temporarily. Oxygen was delivered through a rebreathing mask. 8 mg Dexamethasone was given. This did not improve the patient’s condition. Clinical triad of tetany, laryngospasm, and respiratory rate pointed towards diagnosis of hyperventilation and hypocapnia associated with hypocalcaemia. An arterial sample was sent for ABG analysis.

10ml of 10% Calcium Gluconate was administered slowly over next 10 minutes. Meanwhile the source of oxygen was cut off and the patient was allowed to rebreathe the expired carbon dioxide through the facemask. His condition improved in about 15 to 20 minutes and he became comfortable. The tetany was relieved. The ABG values revealed pH=7.56, pO2=129 mm Hg, pCo2=26 mm Hg, HCO3=20, Na=132, K=3.1, and calcium=6.6 mg/dl.

Case 2 :

A 25-year-old woman, ASA status 1, was posted for laparoscopic ovarian cystectomy. End tidal carbon dioxide monitoring was not available.

So as to prevent hypercarbia due to pneumoperitoneum leading to carbon dioxide absorption, anaesthesiologist had pre-emptively hyperventilated the patient. Patient was haemodynamically stable throughout. At the end of the surgery after neuromuscular block reversal and extubation, patient developed laryngospasm and carpopedal spasm.

Patient was fully conscious, and respiratory efforts were good. She had received Atracurium 50 mg in total, and the last dose of relaxant was given 30 minutes before the end of the procedure. Presence of carpopedal spasm clinched the diagnosis of hypocalcaemia due to hyperventilation as opposed to incomplete reversal from anaesthetic drugs.

Discussion :

Hyperventilation is defined as breathing in excess of the metabolic needs of the body, eliminating more carbon dioxide than is produced and consequently, resulting in respiratory alkalosis and an elevated blood pH. When stress induces a need to take a deep breath, the deep breathing is perceived as dyspnoea. The sensation of dyspnoea creates anxiety, which encourages more deep breathing, and a vicious circle is created.

The respiratory alkalosis due to hyperventilation causes increased binding of calcium with albumin, thus reducing the fraction of ionised calcium (which is the active form) giving rise to symptoms of hypocalcemia. A similar picture may be seen in a case of local anaesthesia systemic toxicity. Clinical observation (e.g. Carpopedal spasm) and appropriate timely investigations (ABG) will help arrive at the correct diagnosis.

Most common causes of hypocalcaemia include hypoparathyroidism, vitamin D deficiency, and chronic kidney disease. Symptoms of hypocalcaemia include neuromuscular irritability (including tetany as manifested by Chvostek’s sign or Trousseau’s sign, bronchospasm), electrocardiographic changes, and seizures.

Treatment is dependent upon the cause, but most commonly includes supplementation of calcium and some form of vitamin D or its analogues. Perioperative hypocalcaemia is anticipated in post-thyroid and parathyroid surgery. However, acute hypocalcaemia may be precipitated due to hyperventilation.

Treatment of hypocalcaemia includes intravenous replacement with Calcium Chloride preferably through a central line If it is severe, acute and symptomatic, Calcium Gluconate is the first line of choice. Calcium must be administered slowly, it may cause thrombophlebitis. It is advised that Calcium supplementation intravenously be given only in acute fall of levels, as otherwise, sudden increase of calcium levels in chronic state may cause cardiac irritability and arrhythmias. Abnormalities in magnesium potassium and pH must be corrected simultaneously.

This habit of calling the anaesthetist, after encountering a problem, must be discouraged, and condemned. These are preventable complications, and the presence of a qualified anaesthetist is necessary, before start of a procedure.

References :

  1. Aguilera and R.S.Vaughan. Calcium and the anaesthetist. Anaesthesia 2000
  2. Hyun Soo Moon, Soo Kyung Lee, Ji Hoon Chung, and Chi Bum In. Hypocalcemia and hypokalemia due to hyperventilation syndrome in spinal anesthesia -A case report- Korean J Anesthesiol. 2011 Dec; 61(6): 519–523.
  3. Edwards R, Winnie AP, Ramamurthy S. Acute hypocapnic hypokalemia: an iatrogenic anesthetic complication. Anesth Analg. 1977; 56:786–792.
  4. Bushinsky DA, Monk RD. Electrolyte quintet: Calcium. Lancet. 1998;352:306–311

 

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