Cardiac surgery (week 7) Flashcards
CABG (Coronary Artery Bypass Graft)
creates new routes around stenosed and occluded arteries, allowing sufficient blood flow to deliver oxygen and nutrients to the heart muscle
Clinical features of coronary artery disease
- Angina
- MI
- Asymptomatic
- Dyspnoea
Risk factors in general for CABG
= risk factors for atherosclerosis
Modifiable … smoking, obesity, diabetes, hypertension, sedentary lifestyle, socioeconomic position
Non-modifiable … age, famiy history, male, female after menopause, ethnicity (Maori, Pacific and Indian)
“Beta blockers “
reduce HR, BP and myocardial contractility (capability of shrinking or contracting)
“Nitrates”
Relaxation of smooth muscle, coronary (increasing coronary flow) and peripheral (reducing cardiac work)
What does Cardiopulmonary bypass (CPB) “on pump” do?
superior vena cava => CPB => Aorta
takes over the role of heart and lungs.
- cannulation of R atrium/vena cava
- drainage of blood
- re-oxygenation
- filtration … to avoid emboli
- pressurised & returned to aortic root
Cardioplegic solution
ice cold solution (potasium) … cooling the heart, reducing metabolic requirements and affording a non beating, bloodless heart
How are grafts resected?
endoscopically … a thin tube-like instrument, which has a light and a lens for viewing and a tool to remove tissue.
Grafts used for bypass
- Internal mammary artery (IMA) … better to use; lasts abt 10yrs if lucky; originating from the subclavian artery supplying the anterior chest wall and breast.
- Saphenous vein graft (SVG)
- Radial artery … side effects - sensory loss, swelling
- Gastroepiploeic … stomach artery (rare)
For diabetics, you may want to choose which graft? and why?
not “Saphenous vein graft”
Because leg wounds don’t heal well.
why IMA graft has more advantage than SVG or Radial artery?
- Arterial grafts rarely develop stenosis (narrowing) and have an improved long-term survival compared to vein grafts.
- Unlike vein or radial artery grafts, internal mammary grafts are not fully removed from their original position. One end remains connected and only the other end is separated, and then attached to one of the coronary arteries.
CABG surgery takes about ___ - ___ hrs, and the incision site will be _______.
- 3 - 5 hours
- Sternotomy
CABG: Lines in situ include
- ECG leads
- Mediastinal and Pericardial drain
- Chest drains (if IMA graft)
- Redivac drains (if SVG/radial graft)
- Arterial line (tells BP … if increase, respond and vasodilation)
- CVP line (central venous pressure line)
- Urinary catheter,
- O2
- Temp probes (on foot … if decrease, tells circulation problem = decreased CO)
- SaO2
- IVl (e.g. insulin, morphine)
what’s the effect of “Dobutamine”
increase myocardiac contractility
= incr CO, SV + decr ventricular filling pressure, vascular resistance
why monitor urine outpur?
cause renal artery takes 25% of the CO, so if pee well, it will indicate good CO.
normal hourly urine output
- 5ml/kg/hr
e. g. 70kg px => 35ml/hr
What does “CVP line” do and where does the cannula inserts into?
- monitor circulating BP (= reflects the amount of blood returning to the heart; the ability of the heart to pump the blood into the atrial system)
- Subclavian and Jugular veins
post “Sternotomy” precautions: Typical activity rstrictions for __ - __ weeks: avoid doing ….
6 - 12 weeks
- driving
- no lifting/ pulling/ pushing > 5kg (=10lbs)
- unilateral abduction/ flexion
What is the “worst” and “least” activity after wih chronic sternal instability?
worst = pushing from chair sit to stand least = simultaneous arm elevation
Coronary Angioplasty
a minimally invasive procedure to open blocked coronary arteries (ballooning; usually stent is introduced over the surface of the balloon)
Coronary Angioplasty possible complications
- dissection of plaque
- rupture of vessel
- acute closure of vessel
Prehabilitation reduces the incidence of PPC and reduces the LOS and improves HRQOL in Px undergoing CABG surgery. T or F?
True [but 2 different studies]
(high risk Px: reduced incidence of PPC)
(low risk Px: reduced the LOS and improved HRQOL … did exercise, education, reinforcement and telemonitoring)
Usual post CABG regime - low risk or uncomplicated surgery (Day 0 - Day 5)
Day 0 or Day 1: extubated and sat up in bed
Day 1: SOOB (sitting out of bed), back to surgical ward
Day 2: Commence mobility (ambulation)- all lines down (drains out)
Day 3: Mob (Ambulation) hourly increasing independence
Day 4: Stairs
Day 5: onwards home
There are some evidence that post cardiac surgery prophylactic respiratory therapy is beneficial. T or F?
False, evidence is lacking
no need of DBE or Couging as long as “early ambulation”
