A 56 year old woman 1 hr post cardiac surgery has a high blood pressure in the ICU. Give likely causes for her high blood pressure and the potential complications this may cause in the early post operative period.
Inadequate analgesia or sedation vs paralysis
Endotracheal tube intolerance
Wrong dosing of inotropes/vasopressors
Post AVR for AS
Bleeding from aortic cannulation site
Extension of a dissection
Apparently, hypertension can occur in 15-40% of post-cardiac surgery patients. It receives a little less interest than hypotension. Note how the college answer has few points which are actually specific to cardiothoracic surgery. And where is hypothermia? That surely plays a role.
The college answer then goes on to mention arrhythmias and hypertensive crises as potential complications. I would have added the effects of increased afterload on myocardial oxygen consumption, the additional stress on new valve components, increase of pre-existing mitral regurgitation, increased sedation demands and thus potentially a delay of extubation, and complications related to the use of antihypertensive polypharmacy.
Anyway; the complete list of causes and consequences looks like this:
- Inadequate sedation in a partially paralysed patient
- Pre-existing hypertension, and the perioperative cessation or regular medications
- Artifactual hypertension (measurement error)
- Unintelligent use of vasopressors
- The sudden improvement of aortic flow following the repair of a stenotic aortic valve, which exposes the systemic circulation to being bullied by a massively hypertrophied left ventricle.
- Increased bleeding risk - particularly from the aortic cannulation site
- Extension of an arterial dissection
- Increased afterload and thus increased LV workload
- Thus, increased risk of ischaemia
- Increased risk of cardiac failure due to decompensated LV failure
- Increased stress on grafted valves or repaired aortic root
- Worsening of existing mitral regurgitation
- Increased need for sedation
- Bleeding from aortic cannulation site
Estafanous, Fawzy G., and Robert C. Tarazi. "Systemic arterial hypertension associated with cardiac surgery." The American journal of cardiology 46.4 (1980): 685-694.
Roberts, A. J., et al. "Systemic hypertension associated with coronary artery bypass surgery. Predisposing factors, hemodynamic characteristics, humoral profile, and treatment." The Journal of thoracic and cardiovascular surgery 74.6 (1977): 846-859.