7. On Monitoring

Says Arthur C. Guyton, “More than 99 per cent of all sensory information is discarded by the brain as irrelevant and unimportant”.

Despite the Flynn effect and increase in average IQ, there are still a lot of...

Arterial Pressure

Transducer requires a zero reference at the level of left atrium.

All air bubbles must be cleared from the system to prevent damping and air embolism.

Nasopharyngeal and tympanic temperatures reflect the temperature of the brain and closely track blood temperature because these sites are highly perfused. Rectal and bladder temperatures provide a measure of core temperature only at equilibrium.

patient’s organism is gazing silently at you and at what you are doing

Altitude has an influence on gas partial pressure

run a paired ABG

CO₂ flush to the field

lactic acidemia

P_aO₂ should probably be kept above 150 mm Hg to assure complete arterial saturation. Whether or not high levels (i.e., >200 mm Hg) are detrimental has not been determined.

Hyperglycemia (>10 mmol/L) aggravates neurologic injury and other morbidity/mortality.

there appears to be a fair amount of O₂ consumption going on

Venous to arterial CO₂ difference should be 10mmHg or less

shunting within the membrane or membrane lung edema would be somewhat refractory to increases in oxygen supplied (as with shunting or embolus in the human lung)

Nonosmotic secretion of arginine vasopressin provoked by surgical stress, pain, hypotension, or nonpulsatile perfusion contributes to the development of hyponatremia by stimulating renal retention of free water.

A 2- to 5-mEq/L decrease in the plasma sodium concentration is expected after beginning cardiopulmonary bypass and does not normally require treatment.

Hyperglycemia or excessive mannitol administration causes pseudohyponatremia by decreasing the plasma sodium concentration.

Increasing serum potassium concentration is manifested by peaked T waves, a widened QRS complex, disappearance of the P wave, heart block, and conduction abnormalities that may be life-threatening.

A typical intravenous dose of glucose and insulin for the acute treatment of hyperkalemia is 1 g/kg of glucose and 1 unit of regular insulin per 4 g of glucose administered (160 ml 40% glucose and 16 units for 65 kg).

Hypokalemia may be caused by increased sympathetic tone during nonpulsatile perfusion.

Hypocalcemia decreases myocardial contractility and peripheral vascular tone and is associated with tachycardia.

Perioperative glucose control effects outcome after heart surgery. Aggressive protocols aimed at maintaining normoglycemia with the use of insulin infusions during cardiac surgery and into the early postoperative period lead to a decrease in morbidity (e.g., sternal wound infection) and possibly mortality.

premembrane and postmembrane pressures should be measured

Venous saturation and hematocrit monitoring

For every 10mmHg deviation from a CO₂ of 40, expect a change in pH of 0.08.

Important Points / Tips