Editing Cardiopulmonary bypass (section)

==Risks and complications==
{| class="wikitable"
|+ Potential complications of cardiopulmonary bypass
|-
! Complication
! Incidence <br/>(events/1000)
! Death or serious <br/>injury (%)
|-
| [[Protamine sulfate|Protamine reaction]]<ref name=":33"/>
| 1.3
| 10.5
|-
| [[Thrombosis]]<ref name=":33"/>
| 0.3–0.4
| 2.6–5.2
|-
| [[Aortic dissection]]<ref name=":33"/>
| 0.4–0.8
| 14.3–33.1
|-
| [[Gas embolism]]
| 0.2–1.3
| 0.2–8.7
|-
| Massive systemic gas embolism<ref name=":33"/>
| 0.03–0.07
| 50–52
|-
| Dislodging of cannula (causing massive bleeding)<ref name=":33"/>
| 0.2–1.6
| 4.2–7.1
|-
| [[Acute respiratory distress syndrome]]<ref name=":33"/>
| –
| –
|-
| [[Arrhythmia|Arrhythmias]]<ref name=":33"/>
| –
| –
|-
| [[Capillary leak syndrome]]<ref name=":1" />
| –
| –
|-
| [[Hemolysis]]<ref name=":1" />
| –
| –
|-
| [[Postperfusion syndrome]] ("pumphead")<ref name=":1" />
| –
| –
|}
CPB is not without risk, and there are a number of associated problems. As a consequence, CPB is only used during the several hours a cardiac surgery may take. CPB is known to activate the coagulation cascade and stimulate inflammatory mediators, leading to hemolysis and coagulopathies. This problem worsens as complement proteins build on the membrane oxygenators.<ref name=":4" /> For this reason, most oxygenators come with a manufacturer's recommendation that they are only used for a maximum of six hours, although they are sometimes used for up to ten hours, with care being taken to ensure they do not clot off and stop working. For longer periods than this, a [[membrane oxygenator]]  is used, which can be in operation for up to 31 days — such as in a Taiwanese case, for 16 days, after which the patient received a heart transplant.<ref>[http://www.physorg.com/news126460484.html Man survives 16 days without a heart] United Press International. April 3, 2008.</ref>

The most common complication associated with CPB is a [[Protamine sulfate|protamine]] reaction during anticoagulation reversal.<ref name=":33"/> There are three types of protamine reactions, and each may cause life-threatening [[hypotension]] (type I), [[anaphylaxis]] (type II), or [[pulmonary hypertension]] (type III).<ref>{{cite journal | vauthors = Nybo M, Madsen JS | title = Serious anaphylactic reactions due to protamine sulfate: a systematic literature review | journal = Basic & Clinical Pharmacology & Toxicology | volume = 103 | issue = 2 | pages = 192–6 | date = August 2008 | pmid = 18816305 | doi = 10.1111/j.1742-7843.2008.00274.x | doi-access = free }}</ref><ref name=":4">{{Cite book|title=Tsra review of cardiothoracic surgery.| vauthors = Lapar DJ |date=2016|publisher=Createspace|isbn=978-1-5232-1716-8 |oclc=953497320}}</ref>  Patients with prior exposure to protamine, such as those who have had a previous [[vasectomy]] (protamine is contained in sperm) or [[Diabetes|diabetics]] (protamine is contained in [[NPH insulin|neutral protamine hagedorn]] (NPH) insulin formulations), are at an increased risk of type II protamine reactions due to cross-sensitivity.<ref name=":4" /> Because protamine is a fast-acting drug, it is typically given slowly to allow for monitoring of possible reactions.<ref name=":1" /> The first step in management of a protamine reaction is to immediately stop the protamine infusion. [[Corticosteroid]]s are used for all types of protamine reactions. [[Chlorphenamine]] is used for type II (anaphylactic) reactions. For type III reactions, heparin is redosed and the patient may need to go back on bypass.<ref name=":4" />

CPB may contribute to immediate cognitive decline. The heart-lung blood circulation system and the connection surgery itself release a variety of debris into the bloodstream, including bits of blood cells, tubing, and plaque. For example, when surgeons clamp and connect the aorta to tubing, resulting emboli may block blood flow and cause mini strokes. Other heart surgery factors related to mental damage may be events of hypoxia, high or low body temperature, abnormal blood pressure, irregular heart rhythms, and fever after surgery.<ref>{{cite web | vauthors = Stutz B | url = http://www.scientificamerican.com/article.cfm?id=pumphead-heart-lung-machine | title = Pumphead: Does the heart-lung machine have a dark side? | work = Scientific American | date = 9 January 2009 }}</ref>