Page 17 - Medicine and Surgery

P1: JYS
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Chapter 1: Perioperative care 13

Clinical features
Perioperative care
The condition may be asymptomatic and diagnosed in-
cidentally on calcium measurement.
The preoperative assessment
Neuromuscular manifestations Underlying any decision to perform surgery is a recog-
Early symptoms include circumoral numbness, paraes- nition of the balance between the risk of the procedure
thesiae of the extremities and muscle cramps. Common and the potential benefits to the patient. All patients un-
but less specific symptoms include fatigue, irritability, dergo a preoperative assessment (history, examination
confusion and depression. Myopathy with muscle weak- and appropriate investigations) both to review the diag-
ness and wasting may be present. Carpopedal spasm nosis and need for surgery, and to identify any coexisting
and seizures are signs of severe hypocalcaemia. Elici- disease that may increase the likelihood of perioperative
tation of Trousseau’s sign and Chvostek’s signs should complications. In general any concerns regarding coex-
be attempted, although it can be negative even in severe isting disease or fitness for surgery should be discussed
hypocalcaemia: with the anaesthetist who makes the final decision re-
Trousseau’s sign: Carpal spasm induced by inflation of garding fitness for anaesthesia.

asphygmomanometerabovesystolicBPfor3minutes.
Chvostek’s sign: Contraction of the ipsilateral facial Cardiac disease

muscles (including the eye, nose and corner of the Ischaemic heart disease remains the most important risk
mouth) after tapping the facial nerve anterior to the factorforpatientsundergoingsurgery.Itisvitalaspartof
ear. apreoperative assessment to identify underlying cardiac
The BP may be low despite fluids or inotropes. Cardiac disease by history, examination and, where appropriate,
failure may occur. investigations. An ECG should be performed in any pa-
Other findings may include papilloedema and in tient with a history suggestive of cardiac disease and in
chronic cases cataracts, dry puffy coarse skin with brittle all patients over 50 years of age.
and thinned hair and nails. Following a myocardial infarction the risk of re-
infarction is maximal over subsequent 6 weeks, if
Investigations surgery is performed the re-infarction rate increases
These are aimed at assessing the severity of hypocal- dramatically. Elective surgery should be deferred by at
caemia to guide management and to look for the under- least 6 months wherever possible.
lying cause. The serum calcium should be checked and Hypertension should be controlled prior to any elec-
corrected for serum albumin (see above). Blood should tive surgery to reduce the risk of myocardial infarction
also be sent for magnesium, phosphate, U&Es and for or stroke. Specialist cardiac advice may be required
PTH level. An ECG should be done to look for ECG prior to emergency surgery in severely hypertensive
changes (increased QT interval, cardiac arrhythmias). patients.
Other investigations depend on the suspected cause. Arrhythmias should ideally be corrected prior to
surgery. Chronic or complex arrhythmias should be
Management discussedwithacardiologistpriortosurgerywherever
This depends on the severity, whether acute or chronic possible.
and the underlying cause. Mild hypocalcaemia is treated Patients with signs and symptoms of cardiac failure
with oral supplements of calcium and magnesium should have their therapy optimised prior to surgery
where appropriate. Severe hypocalcaemia may be life- and require special attention to perioperative fluid
threatening and the first priority is resuscitation as balance.
needed (e.g. management of seizures or cardiac arrhyth- Patients with abnormal or prosthetic heart valves,
mias),followedbytheadministrationofintravenouscal- patent ductus arteriosus or septal defects, and patients
cium. Calcium gluconate contains only a third of the with a history of bacterial endocarditis should have
amount of calcium as calcium chloride but is less irritat- prophylactic oral or intravenous antibiotic cover for
ing to the peripheral veins. any surgical procedures.