Effect of norepinephrine infusion on hepatic blood flow and its interaction with somatostatin: an observational cohort study.

BACKGROUND: Norepinephrine (NE) is a α1-adrenergic mediated vasopressor and a key player in the treatment of perioperative hypotension. Apart from modulating systemic hemodynamics, NE may also affect regional blood flow, such as the hepatic circulation, which contains a wide variety of adrenergic receptors. It may alter regional vascular tonus and hepatic blood flow (HBF) by reducing portal vein flow (PVF) or hepatic arterial flow (HAF). The aim of this study was to assess the effects of NE on HBF. METHODS: Patients scheduled for pancreaticoduodenectomy were included. All patients received standardized anesthetic care using propofol and remifentanil and were hemodynamically stabilized using a goal-directed hemodynamic strategy guided by Pulsioflex™. On surgical indication, somatostatin (SOMATO) was given to reduce pancreatic secretion. HBF measurements were performed using transit-time ultrasound (Medistim™). Baseline hemodynamic and HBF measurements were made after pancreatectomy, at T1. Afterwards, NE infusion was initiated to increase mean arterial pressure (MAP) by 10 - 20% of baseline MAP (T2) and by 20 - 30% of baseline MAP (T3). HBF and hemodynamic measurements were performed simultaneously at these three time-points. RESULTS: A total of 28 patients were analyzed. Administration of NE significantly increased MAP but had no effect on cardiac index. NE infusion reduced total HBF in all patients (p < 0.01) by a reduction HAF (p < 0.01), while the effect on PVF remained unclear. Post-hoc analysis showed that SOMATO-treated patients had a significant lower PVF at baseline (p < 0.05), which did not change during NE infusion. In these patients, reduction of total HBF was primarily related to a reduction of HAF (p < 0.01). In untreated patients, NE infusion reduced total HBF both by a reduction HAF (p < 0.01) and PVF (p < 0.05). CONCLUSION: Administration of NE reduced total HBF, by decreasing HAF, while the effect on PVF remained unclear. SOMATO-treated patients had a lower PVF at baseline, which remained unaffected during NE infusion. In these patients the decrease in total HBF with NE was entirely related to the decrease in HAF. In SOMATO-untreated patients PVF also significantly decreased with NE. TRIAL REGISTRATION: Study protocol EC: 2019/0395. EudraCT n°: 2018-004,139-66 (25 - 03 - 2019). Clin.trail.gov: NCT03965117 (28 - 05 - 2019).

Hemothorax as an Occult Cause of Hypotension After Transseptal Puncture.

BACKGROUND Catheter ablation is an increasingly used treatment modality for arrhythmias. Periprocedural complications have a low incidence but can be life-threatening. Therefore, knowledge of possible risks during the intervention and early recognition improve patient outcomes. Transseptal puncture from the right atrium is needed for left atrial access. This procedure is a critical step that can be complicated by penetrating cardiac injury. CASE REPORT A 76-year-old patient with previous mitral valve port-access surgery underwent catheter ablation for atrial tachycardia. He developed hypotension following a challenging transseptal puncture, but transesophageal echocardiography did not demonstrate any pericardial fluid. After completing the procedure and arriving at the coronary care unit, the patient was found to be in hemorrhagic shock. CT angiography demonstrated a massive right hemothorax without active bleeding. More than 2.5 liters of blood was evacuated by chest drainage. Despite this serious complication, the patient made a full recovery without need for surgical exploration. CONCLUSIONS Hypotension during or shortly after catheter ablation should alert the physician to possible anaphylaxis, hemorrhage, or air embolism. Most patients develop bleeding near the access site or within the pericardial cavity with subsequent tamponade. This case illustrates that hemothorax due to pericardial laceration should be included in the differential diagnosis. Pleural fluid is visible on echocardiography and fluoroscopy during the procedure. Bedside lung ultrasound saves time in detecting a large hemothorax compared to CT scan. Efforts to optimize the safety of transseptal puncture remain important. Radiofrequency transseptal needles and intracardiac echocardiography are helpful tools in patients with difficult atrial septal anatomy.