Cardiovascular Shock

Obstructive shock due to right ventricular compression by a massively expanded reconstructed gastric tube: A case report

Obstructive shock is often associated with poor right ventricular (RV) output and requires rapid obstruction release. A 54-year-old man was brought to our emergency department, presenting with shock. He had previously undergone esophagectomy with gastric interposition through the retrosternal route, after which he could not eat solid foods. After eating a ball of rice, he became critically ill, with a significantly increased lactate level, an indicator of shock. Though initial examinations showed no abnormalities, he was hospitalized for observation. The following day, he experienced similar discomfort while in the supine position, an hour after breakfast. Cardiac sonography revealed that the RV was remarkably compressed by a massively expanded gastric tube, causing diastolic dysfunction. After propping him into a sitting position, he recovered from shock. Upon a second examination of CT images, we recognized the massively dilated gastric tube compressing the RV. Anatomically, the retrosternal route is located directly in front of the RV. Thus, it is thought that the massively dilated gastric tube externally compressed the RV, preventing adequate RV filling and causing the obstructive shock. In such cases, the patient's position should be changed immediately to release the RV compression.

Lactic acidosis and severe septic shock in metformin users: a cohort study

BACKGROUND

High serum lactate is associated with increased mortality in septic shock patients. Metformin alters lactate metabolism, and may affect its prognostic value. We compared, between metformin users and nonusers, the prognosis of extremely elevated plasma lactate levels in patients with septic shock.

METHODS

The electronic medical records (EMR) of patients admitted to the emergency room between January 2011 and June 2013 were reviewed. The study cohort comprised patients with an initial diagnosis of septic shock and blood lactate higher than 10 mmol/L. The selected population was divided into two groups: metformin users (exposed) and metformin nonusers (unexposed). The primary outcome measured was inhospital mortality.

RESULTS

The study included 44 metformin users and 118 nonusers. Metformin users were similar to nonusers with respect to levels of lactate, HCO3, and blood pH; however, they were older and had higher incidence rates of cardiovascular disease and acute kidney injury at admission, compared to nonusers. Inhospital mortality rates were significantly lower in the metformin-treated group, 56.8 % vs. 88.1 %, p <0.0001.

CONCLUSIONS

Though high lactate concentration indicates poor prognosis in septic patients, mortality rate was found to be significantly lower in those who were treated with metformin. This finding may help clinicians in deciding treatment for these patients, who could otherwise be considered too ill for real treatment benefit.

Myocardial protection of early extracorporeal membrane oxygenation (ECMO) support for acute myocardial infarction with cardiogenic shock in pigs

The aim of this study was to explore myocardial protection of early extracorporeal membrane oxygenation (ECMO) support for acute myocardial infarction with cardiogenic shock in pigs. 24 male pigs (34.6 ± 1.3 kg) were randomly divided into three groups-control group, drug therapy group, and ECMO group. Myocardial infarction model was created in drug therapy group and ECMO group by ligating coronary artery. When cardiogenic shock occurred, drugs were given in drug therapy group and ECMO began to work in ECMO group. The pigs were killed 24 h after cardiogenic shock. Compared with in drug therapy group, left ventricular end-diastolic pressure in ECMO group decreased significantly 6 h after ligation (P < 0.05). At the end of the experiments, LV - dp/dt among three groups was significantly different, drug therapy group < ECMO group < control group. There was no difference in LV + dp/dt between drug therapy group and ECMO group. Compared with drug group, myocardial infarct size of ECMO group did not reduce significantly, but myocardial enzyme and troponin-I decreased significantly. Compared with drug therapy, ECMO improves left ventricular diastolic function, and may improve systolic function. ECMO cannot reduce myocardial infarct size without revascularization, but may have positive effects on ischemic areas by avoiding further injuring.

Azygos reflux: a CT sign of cardiac tamponade

Three patients who were investigated with dynamic contrast medium enhanced computed tomography (CT) of the thorax were noted to have pericardial effusions with reflux of contrast medium back along the azygos vein. The diagnosis of cardiac tamponade was not made clinically, but in each case was suggested from the CT findings. Confirmation of the diagnosis was made in all three cases, two patients with echocardiography and one at post mortem. One patient made a rapid recovery following the insertion of a pericardial drain, another made a temporary recovery after pericardiocentesis but the third died. Thirty CT scans performed with similar protocol were reviewed and none of these demonstrated reflux along the azygos vein. The presence of contrast medium refluxing into the azygos vein implies significant haemodynamic disturbance, and in the presence of a pericardial effusion suggests the diagnosis of cardiac tamponade.