A 73-year-old male patient smokes 55 packs of cigarettes a year, without known drug allergies and without previous treatment.
He was admitted for acute coronary syndrome with ST-segment elevation (STEACS), complicated at 72 hours with post-infarction angina.
A hemodynamic study revealed an obstruction of 90% of the right coronary artery (RC), 70% in the anterior descending (AD), 90% in the first diagonal, 70% in the bisectoris and 70% in the circumflectoris.
Catheterization showed an ejection fraction of 75% with normal left ventricular end-diastolic pressure.
In a medical-surgical session, the patient was accepted for surgery, and treatment with carvedilol, captopril, amyloidosis, simvastatin and acetylsalicylic acid was established.
At 30 days, a programmed myocardial revascularization was performed using saphenous vein grafts to DC and diagonally and mammary artery to DA, during the procedure a 112-hour CPB time was maintained hypothermia - 76 minutes and remifentanil - 27 minutes.
Standard cardiopulmonary bypass with pulsatile flow was used.
Heparin activity was antagonized with protamine.
The pump output was normal and there were no intraoperative incidents.
On admission to the Intensive Care Unit, he showed the following hemodynamic parameters: mean arterial pressure (MAP) of 77 mmHg, with dobutamine infusion at 4.5 μg.kg-1.min-1, pulmonary artery pressure of 80 l/min
Cardiac output (CG) was 6.8 l/min, with an index (CI) of 3.35 l/min/m2.
In only 2 hours of evolution, the patient presented hemodynamic deterioration, with marked hypotension despite adding noradrenaline infusion to 0.4 μg.kg-1.min-1 and increasing dobutamine dose to 8 μg.kg-1.min-1.
The patient was managed conservatively.
Mediastinal drainages were scarce.
The chest X-ray showed no parenchymal condensation images, the Swan-Ganz catheter was in a correct position and showed no changes in the electrocardiogram (ECG).
2.200 cc were administered between crystalloids and colloids in one hour, i.e. approximately 30 ml/kg (weight: 70 kg) and noradrenaline infusion was increased above 0.5 μg.kg-1.min-1.
Dobutamine infusion was maintained at the same doses.
Sedation was performed with low doses of midazolam.
Echocardiographic control ruled out other complications.
Central temperature was 35oC and there was no early rewarming, according to the usual pattern.
Due to the presence of data compatible with postoperative vasoplegia refractory to treatment, it was decided to use methylene blue.
However, blood cultures were negative.
In addition to requesting the corresponding consents, family members were informed about the use of this medication.
Hemodynamic parameters measured with the pulmonary artery catheter before and at various times after infusion of methylene blue are shown in Table 1.
A spectacular hemodynamic response was observed at the time of infusion, which was maintained over time.
It allowed the removal of noradrenaline, normalizing AMT and increasing systemic vascular (SVR) and pulmonary (PVR) resistance.
No changes were observed in arterial gas.
1.
Methylene blue was administered in doses of 2 mg/kg diluted in 250 cc of 5% dextrose, over 60 minutes.
No adverse effects of interest were observed, except for urine staining.
There was no renal failure, maintaining normal values of urea and creatinine and diuresis preserved.
Hemoglobin levels did not change and did not present coagulation disorders or liver failure.
Methemoglobinemia level was not determined, although this adverse effect, like the others, is described with the use of doses much higher than those used in our case.
After stabilization of the extubated patient 24 hours after admission, the discharge was prolonged preventively until 72 hours, without complications.
Hospital discharge occurred 11 days later and no late complications were observed.
