Download Hypothermia Post Cardiac Surgery

Hypothermia Post Cardiac Surgery
9/11/10
SP Notes
FANZCA Notes
- common
- multi-factorial: residual hypothermia post CPB, failure to rewarm, open thoracic cavity, cold
OT, administration of cold fluids
CARDIOVASCULAR
-
increased Q -> fall in Q when T<35 C
increased SVR -> poor peripheral perfusion
increased myocardial ischaemia and infarction (catecholamine release mediated)
increased arrhythmia (AF and VT)
hypotension on warming because of vasodilation
RESPIRATORY
-
increased chance of laryngospasm
increased O2 demand (shivering)
shift of oxygen-Hb dissociation curve to left -> decreased O2 off loading
bronchodilation -> increased dead space, decreased hypoxic pulmonary vasoconstriction
longer time on mechanical ventilation
CENTRAL NERVOUS SYSTEM
-
decreased sensitivity to hypoxia and hypercapnoea
increased sensitivity to opioids and sedatives
decreased LOC (agitation and confusion)
decreased cerebral function
decreased protection of airway
NEUROMUSCULAR
- increased duration of action of; NMBD, volatiles (increase in tissue solubility), propofol and
fentanyl
- increased shivering and shiver like tremor (thermal discomfort) -> increased metabolic rate,
myocardial work, oxygen consumption
RENAL
- polyria (electrolyte loss)
- decreased ADH
- decreased RBF and GRF
HAEMATOLOGICAL
Jeremy Fernando (2011)
- coagulation and increased blood loss – reduced number of platelet activators, release of
circulating anti-coagulants
- fibrinolysis -> increased bleeding and transfusion risk
- increased viscosity -> increased VTE risk, poor microcirculation perfusion
METABOLIC
- hyperglycaemia (decrease peripheral utilisation of glucose)
- acidosis from poor peripheral perfusion
INFECTIONS/WOUND
- increase in wound infections – vasoconstriction -> decreased O2 supply, impairs immune
function
- slow wound healing
HEPATIC
- decreased hepatic blood flow
- decreased enzyme activity
- slower drug metabolism
RESOURCE ALLOCATION
- longer ICU stay
Jeremy Fernando (2011)