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Aim
Haemodynamic management
Blood transfusion
Extubation
Urine output
Agitated patient
Epidural
Inotropes
Antibiotics
Intercostal catheters
Warfarin
IABP
Prefences for postoperative management in ICU
CABG or Valve Surgery
Aim Download in PDF
Adequate cardiac output with near-normal blood pressure, excellent pain relief, and early extubation.
Haemodynamic Management – “Tight and Dry Philosophy” for the first 12 hours*
1. BP systolic within 20mmHg of preoperative systolic BP. Always > 100mmHg systolic
2. Cardiac Index > 2.2 L/min/m2. Note that patients with severe diastolic dysfunction typically operate
at CI 1.8-2.2, and if otherwise stable, this should be accepted.
SVRI < 1800 – Noradrenaline for SVRI > 1800
3. Low filling pressure
(Assess only with normal SVRI) SVRI > 1800 – Bolus volume
Low Filling pressure – Bolus Volume
4. CI < 2.0 + SVRI > 1800
Normal / high filling pressure – Inotropes
* After which normal maintenance fluids should also be administered
The Tight and Dry philosophy refers to avoiding a vasodilated state by the deliberate use of a noradrenaline infusion perioperatively. The Noradrenaline infusion is commenced prior to induction of ananesthesia and allows us to avoid excessive fluid administration. It is important to appreciate that perioperative vasodilation occurs from many factors including the anaesthetic drugs, epidural analgesia and most importantly a sterile inflammatory syndrome that is related to cardiopulmonary bypass and to the surgery. This typically lasts 12-36 hours. The aim is to treat vasodilation with vasoconstricors rather than by the administration of crystalloid or colloid fluids. We aim for neutral fluid balance - and fluid administration should primarily be used to replace maintenance requirements and ongoing losses. This change in practice has resulted in a reduction in the degree of haemodilution of the patient which has quite significant secondary effects. Oedema of the patient is less, and more importantly the haemoglobin and clotting factor concentrations are higher resulting in reduced red blood cell transfusion and less bleeding due to better preservation of coagulation.
Remember: a vasodilated state results in “low filling pressures” and filling should not be undertaken until the filling pressures are assessed when the resistance (SVRI) is within or near to the normal range. Please also remember that fluid is required for insensible losses as measured losses..
Blood product transfusion
A haemoglobin of 7.0 should be considered the threshold for transfusion, with a haemoglobin of 8.0 being considered if there are extenuating circumstances. Clotting factors should be used selectively and preferably with consultation. Remember that use of clotting factors will cause haemodilution, usually requiring RBC transfusion as a consequence.
Extubation
There should be a specific reason to keep a patient ventilated after emergence from anaesthesia.
Having completed the surgery, the preference is to cease the anaesthetic and awake the patient expeditiously and avoid the scenario of continuing the anaesthetic / sedation for a “routine” number of hours. The use of propofol to lower blood pressure is considered to be not ideal, since the side-effect is to deepen and prolong anaesthesia. If the blood pressure is problematic, then a vasodilator or lessening of vasoconstrictor would be preferred. In patients with an epidural running, the dose of propofol required for sedation is usually reduced due to less pain stimulus from the surgical site.
Urine output
A urine output of more than 30 mL per hour is preferred. Small dose intermittent lasix would be reasonable in the first instance. However frequently, the low urine output will also reflect a pre-renal insult where a chronically hypertensive patient has a blood pressure 100-110 mmHg systolic, which reflects relative hypotension for them. It is requested that an increase in vasoconstrictor be used in order to elevate the blood pressure closer to the normal preoperative blood pressure for that patient. For example - A blood pressure of 150mmHg systolic would be preferable for a patient whose preoperative blood pressure was 170 mmHg systolic. Specifically, the mean blood pressure seems to be of lesser value in my own consideration than the systolic blood pressure.
The agitated patient
Consider using a short acting sedative rather than Haloperidol. Consider alcohol or drug withdrawal state and treatment with replacement therapy early.
Epidural
The idea of the epidural is to achieve complete pain relief. Please note that the testing of blocks with ice is often unsatisfactory when using Ropivocaine. Simply, if the patient is free of pain then the dose is adequate. If the patients have numbness or weakness affecting the ulnar border of the arms and no pain then the dose can be reduced. The epidural should not be "weaned". The dose of Heparin should be withheld on the day that it is removed and then administered 4 hours following removal.
Remember: “turn down, not off”. The practice of stopping the epidural for an hour to reduce the block is not necessary and results in pain to the patient. Turn down by 2 mL/hr and be patient. Please refer to the detailed notes on epidurals attached to the epidural form and please consult if there are problems. The half-life of Ropivocaine is long, and so adjustments will not equilibrate to a new steady state within 4 hours. Also do not give IV morphine in combination with epidural morphine as there are potent synergistic respiratory depressant effects.
Do not treat hypotension by turning the epidural down – the haemodynamic effect of the epidural is small in comparison to the postoperative inflammatory state – all you will do is put the patient in pain. Rather, increase the noradrenaline infusion rate. A high thoracic epidural will affect about 50% of the sympathetic nerves, to the upper body and not to the lower body including the capacitance veins of the legs.
Inotropes
The preference for Inotropes is Dobutamine. If this agent has been commenced in the operating theatre then it should not be weaned quickly except in unusual circumstances. Typically it should be continued for 24 hours or more following surgery. Please do not reduce the inotrope in the setting of vasodilation in order to reduce cardiac output; rather correct the vasodilation first. In patients with very poor ventricular function there is often several hours following cessation where the haemodynamics remain preserved, and then deterioration occurs.
Antibiotics
24 hours CABG, 48 hours Valves.
Inpatients > 3 days: Vancomycin, Ceftriaxone [Amoxicillin]
Elective: Flucloxicillin [3rd generation cephalosoporin], Ceftriaxone [Amoxicillin]
Intercostal catheters
These should be removed on the morning of the second day postoperative except in exceptional circumstances.
Warfarin
Following all mechanical valves and all tissue valves unless otherwise specified, a small dose of Warfarin should be given on the evening of the first postoperative day. Dose ranges would usually be 2-5 mg.
Target INR:
Atrial fibrillation: 2.0-2.5
Aortic valve replacement: 2.5-3.0
Mitral valve replacement: 3.0-3.5
Tissue prosthesis should have Warfarin for six weeks, unless there are other extenuating circumstances.
Intra-aortic balloon pump
In general it is much preferred that the mechanical support be withdrawn before inotrope support. Therefore, as soon as is possible, the Intraaortic balloon pump is removed whilst maintaining inotrope support. The method of weaning should be to reduce the percent augmentation from 100% to 50% in 10% increments over approximately 4-6 hours. An additional 2-3 hours is spent at 50% augmentation ensuring haemodynamic stability. Thereafter the balloon pump is withdrawn completely. Pressure on the femoral artery should continue for 30-40 minutes. Heparin should be withheld prior to removal and not administered for 4 hours following withdrawal.