Inferior vena cava ultrasonography before general anesthesia cannot predict arterial hypotension in patients undergoing vascular surgery.

INTRODUCTION: Intraoperative hypotension (IH) is an independent predictor of mortality. Some experts have suggested that ultrasound measurement of the inferior vena cava (IVC) in spontaneous ventilation can predict IH. OBJECTIVE: To evaluate the capacity of ultrasound measures of IVC in spontaneous ventilation to predict episodes of IH after anaesthesia induction. PATIENTS AND METHODS: We studied 55 high-risk cardiac patients undergoing vascular surgery. The maximum (dIVCmax) and minimum (dIVCmin) diameter of the IVC were measured and the collapsibility index CI = (dIVCmax-dIVCmin)/dIVCmax was calculated prior to anaesthesia induction. Three definitions of IH were used: systolic blood pressure (SBP) less than 100 mmHg, mean arterial pressure (MAP) less than 60 mmHg, and a decrease in MAP greater than or equal to 30% compared to baseline. RESULTS: There were no significant differences in dIVCmax or in CI between patients presenting IH after anaesthesia induction and those who did not. ROC curves for dIVCmax showed an area under the curve of 0.55 (0.39-0.70), 0.69 (0.48-0.90), and 0.57 (0.42-0.73) and ROC curves for the CI were 0.62 (0.47-0.78), 0.60 (0.41-0.78) and 0.62 (0.47-0.78) for the 3 definitions of IH (<100 mmHg, MAP < 60 mmHg, and MAP ≥30% baseline), respectively. CONCLUSIONS: Ultrasound measurements of IVC in spontaneous ventilation are not good predictors of IH after anaesthesia induction in these patients. The optimal cut-off points show low specificity and moderate sensitivity for predicting IH.

Ultrasound-based clinical profiles for predicting the risk of intradialytic hypotension in critically ill patients on intermittent dialysis: a prospective observational study.

BACKGROUND: Intradialytic hypotension, a complication of intermittent hemodialysis, decreases the efficacy of dialysis and increases long-term mortality. This study was aimed to determine whether different predialysis ultrasound cardiopulmonary profiles could predict intradialytic hypotension. METHODS: This prospective observational single-center study was performed in 248 critically ill patients with acute kidney injury undergoing intermittent hemodialysis. Immediately before hemodialysis, vena cava collapsibility was measured by vena cava ultrasound and pulmonary congestion by lung ultrasound. Factors predicting intradialytic hypotension were identified by multiple logistic regression analysis. RESULTS: Intradialytic hypotension was observed in 31.9% (n = 79) of the patients, interruption of dialysis because of intradialytic hypotension occurred in 6.8% (n = 31) of the sessions, and overall 28-day mortality was 20.1% (n = 50). Patients were classified in four ultrasound profiles: (A) 108 with B lines > 14 and vena cava collapsibility > 11.5 mm m-2, (B) 38 with B lines < 14 and vena cava collapsibility ≤ 11.5 mm m-2, (C) 36 with B lines > 14 and vena cava collapsibility Di ≤ 11.5 mm m-2, and (D) 66 with B lines < 14 and vena cava collapsibility > 11.5 mm m-2. There was an increased risk of intradialytic hypotension in patients receiving norepinephrine (odds ratios = 15, p = 0.001) and with profiles B (odds ratios = 12, p = 0.001) and C (odds ratios = 17, p = 0.001). CONCLUSION: In critically ill patients on intermittent hemodialysis, the absence of hypervolemia as assessed by lung and vena cava ultrasound predisposes to intradialytic hypotension and suggests alternative techniques of hemodialysis to provide better hemodynamic stability.

Utility of transesophageal echocardiography during severe hypotension in non-cardiac surgery.

BACKGROUND AND OBJECTIVES: Severe and refractory hypotension is an infrequent perioperative situation during non-cardiac surgery, but determining its etiology is essential for successful management and therapy. METHODS: Adults undergoing non-cardiac surgery were prospectively enrolled in this study. Severe hypotension was defined as a drop from 30% of baseline systolic arterial pressure unresponsive to adequate fluids administration and to ephedrine, according to the anasthesiologist criteria. A multiplanar transesophageal echocardiography (TEE) probe was inserted, prior to any other invasive hemodynamic monitor. RESULTS: Forty two adults (68 ± 12 years) were studied, 84% during elective non-cardiac surgery. Abdominal (open and laparoscopic), thoracic and orthopaedic surgeries were performed most frequently. In all patients, TEE was useful for determining the etiology of severe hypotension. Hypovolemia was diagnosed in 18 patients (42%). Low ejection fraction (EF < 30%) was detected in 5 cases and was successfully treated with vasoactive drugs. Dynamic left ventricular outflow tract obstruction, associated with systolic anterior motion of the mitral valve, was diagnosed in 5 patients; in another 6 patients severe embolism was detected during hip and knee surgery. Myocardial ischemia causing persistent hypotension was detected in 5 patients; in 3 patients, cardiac tamponade was the etiology of severe hypotension. Two patients died; both had severe myocardial ischemia. CONCLUSIONS: Perioperative TEE was performed quickly, proving to be a useful technique in the context of hypotension during non-cardiac surgery. The heart and great vessels could be observed directly and functionally evaluated. Thus, the etiology of severe hypotension could be easily determined and managed.

[Intraoperative diastolic dysfunction as a risk factor for hemodynamic instability]. / Evaluación de función diastólica intraoperatoria con ecocardiografía transesofágica: ¿es útil?

BACKGROUND: Diastolic function can be evaluated intraoperatively using transesoptiageal echocardiography. AIM: To study if intraoperative diastolic dysfunction is associated to a greater number of hemodynamic events during surgery and during the postoperative period. MATERIAL AND METHODS: Patients with indication of intraoperative transesophageal echocardiography due to cardiovascular diseases were included in the study. Diastolic function was assessed measuring transmitral intraventricular filling delay and pulmonary vein now. Patients were divided, according to diastolic dysfunction, in those with derangements in relaxation, pseudonormalization and restrictive patterns. Hypertension, hypotension, ST segment depression, alterations in myocardial contractility, pulmonary congestion and postoperative oliguria were recorded. RESULTS: Fifty eight patients aged 68+/- 12 years (39 males), were studied. Forty four had diastolic dysfunction. Intraoperative hypotension occurred in 82% of patients with diastolic dysfunction and 16% of patients without it. Likewise, hypotension and oliguria during the postoperative period were more common in patients with diastolic dysfunction. CONCLUSIONS: In this group of patients with cardiovascular disease, intraoperative diastolic dysfunction is a risk factor for hemodynamic instability.