Interatrial septum motion but not Doppler assessment predicts elevated pulmonary capillary wedge pressure in patients undergoing cardiac surgery.

BACKGROUND: Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery. METHODS: In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE). RESULTS: Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e' and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and E/e' ratios correlated well with PCWP before anesthesia. After induction of anesthesia using TTE or TEE, correlations were poor. In normal EF patients, correlations were poor for both TEE and TTE at all five stages. The sensitivity and specificity of echocardiographic values were not high enough to predict raised PCWP except for a fixed curve pattern of interatrial septum (area under the curve 0.89 for PCWP ≥ 17, and 0.98 for ≥ 18 mmHg) and S/D less than 1 (area under the curve 0.74 for PCWP ≥ 17, and 0.78 for ≥ 18 mmHg). CONCLUSION: Doppler assessment of PCWP was neither sensitive nor specific enough to be clinically useful in anesthetized patients with mechanical ventilation. The fixed curve pattern of the interatrial septum was the best predictor of raised PCWP.

Review article: Accuracy of emergency physician performed point-of-care ultrasound of the thoracic aorta: A systematic review and narrative synthesis of the literature.

Point-of-care ultrasound (POCUS) is becoming ubiquitous in emergency medicine. POCUS for abdominal aortic aneurysm is well established in practice. The thoracic aorta can also be assessed by POCUS for dissection and aneurysm and transthoracic echocardiography is endorsed by international guidelines as an initial test for thoracic aortic pathologies. A systematic search of Ovid Medline, PubMed, EMBASE, SCOPUS and Web of Science from January 2000 to August 2022 identified four studies evaluating diagnostic accuracy of emergency physician POCUS for thoracic aortic dissection (TAD) and five studies for thoracic aortic aneurysm (TAA). Study designs were heterogeneous including differing diagnostic criteria for aortic pathology. Convenience recruitment was frequent in prospective studies. Sensitivity and specificity ranges for studies of TAD were 41-91% and 94-100%, respectively when an intimal flap was seen. Sensitivity and specificity ranges for studies of thoracic aorta dilation >40 mm were 50-100% and 93-100%, respectively; for >45 mm ranges were 64-65% and 95-99%. Literature review identified that POCUS is specific for TAD and TAA. POCUS reduces the time to diagnosis of thoracic aortic pathology; however, it remains insensitive and cannot be recommended as a stand-alone rule-out test. We suggest that detection of thoracic aorta dilation >40 mm by POCUS at any site increases the suspicion of serious aortic pathology. Studies incorporating algorithmic use of POCUS, Aortic Dissection Detection Risk Score and D-dimer as decision tools are promising and may improve current ED practices. Further research is warranted in this rapidly evolving field.

Core review: physician-performed ultrasound: the time has come for routine use in acute care medicine.

The use of ultrasound in the acute care specialties of anesthesiology, intensive care, emergency medicine, and surgery has evolved from discrete, office-based echocardiographic examinations to the real-time or point-of-care clinical assessment and interventions. "Goal-focused" transthoracic echocardiography is a limited scope (as compared with comprehensive examination) echocardiographic examination, performed by the treating clinician in acute care medical practice, and is aimed at addressing specific clinical concerns. In the future, the practice of surface ultrasound will be integrated into the everyday clinical practice as ultrasound-assisted examination and ultrasound-guided procedures. This evolution should start at the medical student level and be reinforced throughout specialist training. The key to making ultrasound available to every physician is through education programs designed to facilitate uptake, rather than to prevent access to this technology and education by specialist craft groups. There is evidence that diagnosis is improved with ultrasound examination, yet data showing change in management and improvement in patient outcome are few and an important area for future research.

Review article: Clinical impact of non-cardiologist-performed transthoracic echocardiography in emergency medicine, intensive care medicine and anaesthesia.

There is increased realisation of the emerging role of point-of-care transthoracic echocardiography (TTE) as 'ultrasound-assisted examination', given the low sensitivity of clinical examination for cardiovascular pathologies and the time-critical nature of these pathologies. There is evidence that point-of-care TTE provides higher accuracy in patient assessment and management, with potential prognostic impact by assessing the severity of cardiac dysfunction and response to treatment. Point-of-care TTE is increasingly used by non-cardiologists, as a diagnostic, screening or monitoring tool. The literature shows that TTE identifies new clinical findings, and conversely can accurately rule out clinically important pathologies. Recent reports have examined more advanced ultrasound devices and patients in the critical care settings of emergency medicine, intensive care and anaesthesia. The diagnostic capability of new portable devices is improving rapidly and outdating its predecessors, thereby improving confidence in echocardiography findings.