You’ve arrived in the cardiac OR caffeinated and raring to go. The propofol is having an existential crisis and there is enough fentanyl drawn up to tranquillise a horse. You’re nervous and suffering retrograde FRCA amnesia. This section might be for you.
This is a rough guide to anaesthesia for heart surgery in UHS. It is by no means a ‘how to guide’ but should help those seeing it for the first time.
The majority of adult cases are either coronary artery bypass grafting (CABG), or valve surgery, or a combination of the two. In addition you might see emergency chest opening, acute aortic dissection repair, elective aortic surgery, ECMO, balloon pumps, congenital cardiac surgery and cathlab interventional or electrophysiology cases. These will not be covered in this section and are discrete sub-specialist areas.
Patients for elective surgery are given premeds on the ward (with supplemental O2 also written up please). On arrival we check the patients in using the WHO template then enter the relevant patient data (demographics, weight, allergies) onto MetaVision and proceed with the anaesthetic.
After some 1% lidocaine LA a 14G cannula is sited to the right hand/arm. Some people choose to give some extra sedation at this point. A 20G Jelco is used to site the arterial line, usually on the left. When you are in the OR you’ll see the Feng Shui makes sense. The patient has an IV induction and the ETT is sited 8.0 for females and 9.0 for males. Nasopharyngeal (T1) and Axillary (T2) temperature probes are used. It’s a good idea to clock how you’re going to rewarm the patient after CPB, usually it’s warming mattress or a forced air warmer or both. No warming occurs prior to CPB. A central line is sited and USS is available for this.
By convention we use the Arrow 16 cm 5 lumen CVCs. The brown port is the distal lumen – this is used for RA pressure monitoring. The white is hooked up to the propofol infusion run at a rate of 3 mg/kg/hr & the blue is used for inotropes. Occasionally PA sheathes +/- PAC are used for high risk cases, though this has become more infrequent in the echo era.
A nurse or surgeon sites a urinary catheter and, if it is indicated, we put a transoesophageal echo (TOE) probe in. The arms are wrapped carefully, lines checked and then the bar is put in to help establish your mis en place and the blood brain barrier once in the OR.
1.5g of cefuroxime is given unless contraindicated. In true penicillin anaphylaxis, vancomycin 1g is usually used instead.
The A line plunger is pulled back and the clamp rotated through 90 degrees (to prevent contamination) and first a non heparinised sample is aspirated into a syringe to gain a baseline ACT using a vamp, a second heparinised syringe is attached and blood pulled off for an ABG. Isoflurane is usually administered as part of a balanced anaesthetic but its purpose is duel – clearly it is a useful hypnotic but much of its use in the OR is in fine tuning the haemodynamics. For this reason flow will often be left ‘high’ on the back bar to allow rapid equilibration of the ETAA.
The surgery is divided into stages: preparing the mediastinum for going on pump, going on bypass to facilitate the definitive operation, separating from bypass and the post bypass period.
- After skin incision the sternum is divided with a saw. This is extremely stimulating and analgesics must be on board (somewhere in the region of 10 mcg/kg of fentanyl) For first time sternotomies the lungs are turned off at this point to minimise the chance of damage
- If the operation is a CABG the LIMA is first taken off the chest wall. This can take a little while…
- When the surgeon is ready first the aorta is cannulated. The SBP needs to be between 80-100 mmHg at this point to keep everyone happy (minimises risk of iatrogenic dissection)
- Purse strings are placed in a circle on the right atrial appendage and the RA prepared for cannulation. For a CABG a large 2 stage cannula is used which collects blood from both SVC and IVC. Sometimes bicaval cannulation is used and it is important to identify whether your propofol line is caught up in the pipes or not! Arrhythmias are common at this point and usually spontaneously resolve, BP also has a tendency to drift
- Heparin is requested by the surgeons and administered by the anaesthetist at a dose of 300 IU/kg to achieve an ACT of 400s
- Once ACT > 400 this should clearly and loudly be announced and confirmed by the anaesthetist such that everyone understands it is safe to go on. Do not let a patient go on bypass until the ACT > 400
- Once on CPB the next step is usually to cannulate the aortic root with a cardioplegia cannula. Once this is on the cross clamp is applied to the aorta. Both CPB and AXR times need marking on the electronic record.
- CPB = The golden hour. Check the propofol syringe is not about to run out then recaffeinate.
- Make a plan with the consultant for inotropic support and haemostasis as required. The bloodbank can be reached on ext 4620
- Once the lions share of surgery is complete the perfusionist is asked to rewarm the patient. If attached, forced air warmers need turning on now and consultants like to know rewarming has occurred
- Prior to separating from CPB the ABG and FBC from the perfusionist must be checked for Hct/Hb level and plt count. We often employ a transfusion Hb threshold of around 90 g/L and plt count of 100 although this does vary. The patient must be warm, pacing wires must be connected to the box and epicardial pacing must be tested and if required, tidy. Inotropes should be started if needed and lungs turned on. Weaning from CPB is normally done with consultant supervision
Southampton Cardiac Anaesthesia 