**Tamponade**

It is characterized by symptoms and signs of hemodynamic instability due to the restrictive effect on cardiac contraction, usually observed within the first 6hrs associated with poor permeability of their drains. The prevalence of this complication varies between different publications, ranging from 0.8% -8.5%, there are reports in which said one of the most frequent causes, to the use of internal mammary artery for coronary artery bypass bridge, on the other hand, the use of a single anterior mediastinal tube, instead of 2 tubes (front and back) has been associated with a high rate of pericardial fluid and as a result of these patients tamponade.La course evaluation should be carried out by echocardiography, and not just those with a radiological image suggestive of this entity (heart carafe), since by this method because of cardiac surgery postoperative patients identified only 50% of patients. This is important because several studies have shown that those patients who develop pericardial effusion, even without hemodynamic compromise, increased risk of supraventricular arrhythmias, sternal dehiscence, prolonged hospital stay and a significant reduction in exercise tolerance. 82,83,84

Finally, the treatment will be those with hemodynamic compromise, is permeated drains, by performing emergency echocardiography and reoperation. 85,86,87,88,89

### **Vasoplegic Syndrome**

Vasoplegic syndrome (SV) is a severe form of systemic inflammatory response syndrome (SIRS), which ranks its expression on the cardiovascular system. A number of reports considered the vasoplegia as a recognized complication of cardiac surgery, the main clinical manifestation is the presence of hypotension, usually severe, which features the distinctive clinical feature of responding with little or no input from volume.

In cardiac surgery, the reported incidence is 8 to 10%, even up to 40%, these differences often depend on characteristics of the study population (ventricular function), the type of intervention assessed (use or not of CPB, type cardioplegia) and mainly from the diagnostic criteria used. As mentioned previously, the key point is the presence of hypotension, usually with a systolic blood pressure (SBP) <85 mm Hg, and / or mean arterial pressure (MAP) <50 mm Hg.Un clinical data necessary to consider the diagnosis of Vasoplegia is the lack of response to volume expansion. A hypotensive patient in the postoperative period of cardiac surgery, central venous pressure (CVP) reduced elevation of the same after the infusion of 500 or 1000 ml of solutions (even at higher volumes) should lead to the posing of vasoplegia. 90,91,92,93

Strict diagnostic confirmation will require the use of hemodynamic monitoring, the presence of Swan Ganz catheter will allow a broader determination descended filling pressures, by providing values of pulmonary capillary pressure (PCP) reduced.

### **Diagnostic criteria**


Reduced systemic vascular resistance (SVR <800 dinas/seg/cm-5)

Vasopressor requirement (> 0.5 mcg / kg / min noradrenaline or> 10 mcg / kg / min dopamine)

3. Other

26 Special Topics in Cardiac Surgery

It is characterized by symptoms and signs of hemodynamic instability due to the restrictive effect on cardiac contraction, usually observed within the first 6hrs associated with poor permeability of their drains. The prevalence of this complication varies between different publications, ranging from 0.8% -8.5%, there are reports in which said one of the most frequent causes, to the use of internal mammary artery for coronary artery bypass bridge, on the other hand, the use of a single anterior mediastinal tube, instead of 2 tubes (front and back) has been associated with a high rate of pericardial fluid and as a result of these patients tamponade.La course evaluation should be carried out by echocardiography, and not just those with a radiological image suggestive of this entity (heart carafe), since by this method because of cardiac surgery postoperative patients identified only 50% of patients. This is important because several studies have shown that those patients who develop pericardial effusion, even without hemodynamic compromise, increased risk of supraventricular arrhythmias, sternal dehiscence, prolonged hospital stay and a significant

Finally, the treatment will be those with hemodynamic compromise, is permeated drains, by

Vasoplegic syndrome (SV) is a severe form of systemic inflammatory response syndrome (SIRS), which ranks its expression on the cardiovascular system. A number of reports considered the vasoplegia as a recognized complication of cardiac surgery, the main clinical manifestation is the presence of hypotension, usually severe, which features the distinctive

In cardiac surgery, the reported incidence is 8 to 10%, even up to 40%, these differences often depend on characteristics of the study population (ventricular function), the type of intervention assessed (use or not of CPB, type cardioplegia) and mainly from the diagnostic criteria used. As mentioned previously, the key point is the presence of hypotension, usually with a systolic blood pressure (SBP) <85 mm Hg, and / or mean arterial pressure (MAP) <50 mm Hg.Un clinical data necessary to consider the diagnosis of Vasoplegia is the lack of response to volume expansion. A hypotensive patient in the postoperative period of cardiac surgery, central venous pressure (CVP) reduced elevation of the same after the infusion of 500 or 1000 ml of solutions (even at higher volumes) should lead to the posing of vasoplegia.

Strict diagnostic confirmation will require the use of hemodynamic monitoring, the presence of Swan Ganz catheter will allow a broader determination descended filling pressures, by

Minute volume and normal or elevated cardiac index (CI equal to or greater than 2.5

Low blood pressure response with little or no volume expansion aapropiada

Reduced filling pressures (CVP <5 mm Hg / Wedge <10 mm Hg)

Reduced systemic vascular resistance (SVR <800 dinas/seg/cm-5)

performing emergency echocardiography and reoperation. 85,86,87,88,89

clinical feature of responding with little or no input from volume.

providing values of pulmonary capillary pressure (PCP) reduced.

Hypotension (SBP <85 mm Hg / TAM <50 mm Hg)

1. Clinical (only allow them to suspicion)

**Tamponade** 

reduction in exercise tolerance. 82,83,84

**Vasoplegic Syndrome** 

90,91,92,93

**Diagnostic criteria** 

2. Hemodynamic

L/min/m2)

a. In operating room, with open chest

PVC hypotension with low (<5 mm Hg) refractory avolumen associated with excellent observation of left ventricular contractility.

b. postoperative

PVC hypotension with low (<5 mm Hg) refractory avolumen associated with echocardiography (bidimensionalcon good window or transesophageal) with apreciaciónde good left ventricular contractility.

The main therapeutic goal is sustain perfusion to vital organs like the kidney, brain, liver and heart. This also implies the initial use of volume, the use of two types of drugs, drugs with pressor effect, linked to its exclusive or non-selective action on alpha adrenergic receptors, such as metaraminol or phenylephrine among the first, and epinephrine, norepinephrine or dopamine among the latter. The use of drugs associated with betaadrenergic effect, will result in some measure, an increase of myocardial oxygen consumption in the same direction, their association with postoperative arrhythmias, has also been reported. The second drawback associated with, and probably the most important clinical refractoriness to vasopressors is that certain forms of vasoplegia postoperative manifest. This refractoriness drugs raises the utility of antagonists or inhibitors of NO and the enzyme guanylate cyclase, we consider a rational therapeutic approach more physiological. Two drugs are the most studied, methylene blue, and vasopressin 94,95,96,97,98

Methylene Blue (AM): its therapeutic action is based on the inhibitory effect of NO or blocking of the enzyme guanylate cyclase. This drug has been considered in several isolated reports in a series without a control group and essentially in a randomized control group. Leyh et al. reported 54 patients with refractory postoperative vasoplegia the use of norepinephrine, treated with 2 mg / kg AM. Fifty-one patients showed favorable hemodynamic changes in the course of one hour post-treatment. Three patients died in the hospital course of the picture (5.6%). The study lacked a control group. Another key finding is the shorter of the table between those treated with AM. In these, vasoplegia resolved completely within two hours after the start of infusion, whereas in those managed conventionally, the box is extended in time, such extension of time associating with a higher incidence of complications and late onset sepsis and multiorgan dysfunction . Several authors have agreed with this finding, giving unfavorable prognostic value of the persistence over time of the SV, accepting that a breakpoint located between 36 and 48 hours is a marker of poor prognosis.

Vasopressin: Vasopressin (antidiuretic hormone arginine vasopressin), Argenziano et al. described the association between the shock with vasodilatation after bypass surgery and deficiency of vasopressin. Which is secreted by the neurohypophysis regulates tubular permeability to water, typically having limited participation in the control of BP. Under conditions of hypotension, such as bleeding or vasoplegia itself is a rapid depletion of endogenous. It allows a rapid reversal of hypotension, especially in patients refractory to vasopressors. In addition, the hormone increases vascular sensitivity to catecholamines and increases urine output, based on its direct action on glomerular efferent arteriole, unlike catecholamines, whose site is located on the therapeutic afferent arteriole. The proposed dose is 0.05 to 0.1 unit / minute.

Intensive Care Management of Patients in the First 24 Hours After Cardiac Surgery 29

enzyme protects cAMP, promoting their destination to the increase in contractility. It now has a group of inotropic drugs whose mechanism of action is precisely in the inhibition of phosphodiesterase-III. Of this group stand amrinone and milrinone for the extensive clinical experience has accumulated with its use. These substances belong to the bipyridines, this is a positive inotropic effect supplemented by a peripheral vasodilator, which contributes to a better ability to emptying of the heart. The hemodynamic effects of milrinone, administered as a loading dose of 50 micrograms / kg followed by continuous infusion of 0.35 to 0.75 micrograms / kg / min is significant reductions in diastolic pressure in the aorta, the mean aortic pressure and systemic vascular resistance by about 11% ejection fraction of left ventricle is increased by about 14%, these effects are closely related to plasma

In the postoperative period especially in patients receiving milrinone pump has several effects on pulmonary circulation and inotropism as evidenced Mitsunori et al, which randomized 30 patients undergoing cardiac surgery treated with milrinone was reported, reduced the mean pressure of right atrial pressure in the pulmonary artery wedge, mean pulmonary pressure and systemic vascular resistance without making a significant change

On the other hand the use of Milrinone has been shown to be beneficial in patients undergoing CSRC bomb and right ventricular dysfunction prior. Jong H. et al analyzed the effect of infusion of milrinone in patients undergoing CSRC and right ventricular dysfunction (VD) found no increase in cardiac index, heart rate, and decreased systemic vascular resistance. Changes in right ventricular ejection fraction were not significant, whereas in cardiac output and RV afterload if they were, finally improves graft flow in the

Dopamine (D) precursor of norepinephrine in the biological synthesis, there are specific receptors for this substance, especially in the renal circulation, where it produces a vasodilatory effect which favors renal tubular function (Hiberman et.al 1984). At the heart there are dopamine receptors, but its function on contractility is weak and little known, this effect is not accompanied by an increase in resistance as pronounced as with peripheral epinephrine and norepinephrine under in vessels predominantly to dopamine receptor

The mechanism of action is dose dependent at relatively low doses (1-5μg/kg/min) stimulates dopamine receptors predominantly with subsequent renal and mesenteric vasodilation (Szerlip, et. Al 1991). A moderate dose of 5-10 mg / kg / min stimulates beta adrenergic receptors leading to positive inotropic effects and high-dose alpha-adrenergic

By perioperative is used for its effects on the renal circulation as well as its positive inotropic effect can be used in improving the ICC states inotropism significantly, the clinical effect is seen immediately as the drug's half life is 3 -4 min. Among its side effects can cause or exacerbate tachyarrhythmias, because its effect is mediated by increased levels of norepinephrine. At present medical evidence did not show benefit of using low doses of dopamine effect of splanchnic vasodilatation and renal function, however, this drug increases oxygen consumption at promoting tubular tubular ischemia, in addition there is

breast and in the middle cerebral artery during surgery of the CSRC.

stimulation 10-15μg/kg/min carries peripheral vasoconstriction.

poor correlation between blood levels with dose infused.

concentrations. 117,118,119,120

**Dopamine** 

stimulation.

in mean arterial pressure or heart rate.

The use of off-pump surgery was associated with less inflammatory response, with lower incidence of postoperative SV. However, the picture is commonly seen and may present a favorable course. Vasoplegic syndrome is associated with a poor prognosis, when it is resistant norepinerina poorer prognosis with increased morbidity and mortality. The reported mortality after cardiac surgery is 24% in series reported by Levin and colleagues, and 25% in series reported by Gómez et al, in which case the syndrome persisted for up to 48hr vasoplegic. 99,100,101,102,103
