Transgastric Abdominal Ultrasonography in Anesthesia and Critical Care: Review and Proposed Approach

Measuring and maintaining organ perfusion in a patient with Takayasu's arteritis undergoing cardiac surgery

Takayasu's arteritis is a rare vasculitis affecting the aorta and its branches. Disease progression can result in arterial stenosis and subsequent organ dysfunction. Estimating organ perfusion by measuring the peripheral blood pressure can be challenging because it may be altered by arterial stenosis. We report the case of a 61-year-old woman with Takayasu's arteritis with aortic and mitral regurgitation who presented for aortic valve replacement and mitral valvuloplasty. Peripheral arterial pressure was considered a less reliable surrogate for organ perfusion because the patient had diminished blood flow in both the lower and upper extremities. In addition to the bilateral radial arterial pressure, the blood pressure in the ascending aorta was monitored to estimate the patient's organ perfusion pressure during cardiopulmonary bypass. The initial target blood pressure was determined based on the pre-operative baseline and modified by measurement of the aortic pressure. Cerebral oximetry using near-infrared spectroscopy and mixed venous saturation was monitored to estimate oxygen supply-demand balance, which helped evaluate cerebral perfusion and determine the transfusion threshold. The entire procedure was uneventful, and no organ dysfunction was observed postoperatively.

Pulmonary Vasodilator Response of Combined Inhaled Epoprostenol and Inhaled Milrinone in Cardiac Surgical Patients

BACKGROUND

Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. Intraoperative management of patients at high risk of RV failure should aim to reduce RV afterload and optimize RV filling pressures, while avoiding systemic hypotension, to facilitate weaning from cardiopulmonary bypass (CPB). Inhaled epoprostenol and inhaled milrinone (iE&iM) administered in combination before CPB may represent an effective strategy to facilitate separation from CPB and reduce requirements for intravenous inotropes during cardiac surgery. Our primary objective was to report the rate of positive pulmonary vasodilator response to iE&iM and, second, how it relates to perioperative outcomes in cardiac surgery.

METHODS

This is a retrospective cohort study of consecutive patients with PH or RV dysfunction undergoing on-pump cardiac surgery at the Montreal Heart Institute from July 2013 to December 2018 (n = 128). iE&iM treatment was administered using an ultrasonic mesh nebulizer before the initiation of CPB. Demographic and baseline clinical data, as well as hemodynamic, intraoperative, and echocardiographic data, were collected using electronic records. An increase of 20% in the mean arterial pressure (MAP) to mean pulmonary artery pressure (MPAP) ratio was used to indicate a positive response to iE&iM.

RESULTS

In this cohort, 77.3% of patients were responders to iE&iM treatment. Baseline systolic pulmonary artery pressure (SPAP) (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.24-2.16 per 5 mm Hg; P = .0006) was found to be a predictor of pulmonary vasodilator response, while a European System for Cardiac Operative Risk Evaluation (EuroSCORE II) score >6.5% was a predictor of nonresponse to treatment (≤6.5% vs >6.5% [reference]: OR, 5.19; 95% CI, 1.84-14.66; P = .002). Severity of PH was associated with a positive response to treatment, where a higher proportion of responders had MPAP values >30 mm Hg (42.4% responders vs 24.1% nonresponders; P = .0237) and SPAP values >55 mm Hg (17.2% vs 3.4%; P = .0037). Easier separation from CPB was also associated with response to iE&iM treatment (69.7% vs 58.6%; P = .0181). A higher proportion of nonresponders had a very difficult separation from CPB and required intravenous inotropic drug support compared to responders, for whom easy separation from CPB was more frequent. Use of intravenous inotropes after CPB was lower in responders to treatment (8.1% vs 27.6%; P = .0052).

CONCLUSIONS

A positive pulmonary vasodilator response to treatment with a combination of iE&iM before initiation of CPB was observed in 77% of patients. Higher baseline SPAP was an independent predictor of pulmonary vasodilator response, while EuroSCORE II >6.5% was a predictor of nonresponse to treatment.

Transesophageal Echocardiography in Patients in Cardiac Arrest: The Heart and Beyond

Point of care ultrasound involves different ultrasound modalities and is useful to assist management in emergent clinical situations such as cardiac arrest. The use of point of care ultrasound in cardiac arrest has mainly been described using transthoracic echocardiography as a diagnostic and as a prognostic tool. However, cardiac evaluation using transthoracic echocardiography might be challenging because of patient-related or technical factors. Furthermore, its use during pulse check pauses has been associated with delays in chest compression resumption. Transesophageal echocardiography (TEE) overcomes these limitations by providing reliable and continuous imaging of the heart without interfering with cardiopulmonary resuscitation. In this narrative review we describe the role of TEE during cardiopulmonary resuscitation in 4 different applications: (1) chest compression quality feedback; (2) rhythm characterization; (3) diagnosis of reversible causes; and (4) procedural guidance. Considering its limitations, we propose an algorithm for the integration of TEE in patients with cardiac arrest with a focus on these 4 applications and extend its use to extracardiac applications.

Inhaled Epoprostenol and Milrinone Effect on Right Ventricular Pressure Waveform Monitoring

BACKGROUND

Pulmonary hypertension (PH) and right ventricular (RV) dysfunction are major complications in cardiac surgery. This study aimed to evaluate the change in RV pressure waveform in patients receiving a combination of inhaled epoprostenol and inhaled milrinone (iE&iM) before cardiopulmonary bypass (CPB) and to assess the safety of this approach with a matched case-control group.

METHODS

A prospective single-centre cohort study of adult patients undergoing cardiac surgery administered iE&iM through an ultrasonic mesh nebulizer. RV pressure waveform monitoring was obtained by continuously transducing the RV port of the pulmonary artery (PA) catheter.

RESULTS

The final analysis included 26 patients receiving iE&iM. There was a significant drop in mean PA pressure (MPAP) (-4.8 ± 8.7, P = 0.010), systolic PA pressure (SPAP) (-8.2 ± 12.8, P = 0.003), RV end-diastolic pressure (RVEDP) (-2.1 ± 2.8, P < 0.001) and RV diastolic pressure gradient (RVDPG) (-1.7 ± 1.4, P < 0.001) after 17 ± 9 minutes of iE&iM administration. Patients also had a significant increase in RV outflow tract (RVOT) gradient (3.7 ± 4.7, P < 0.001), RV maximal rate of pressure rise during early systole (dP/dt max) (68.3 ± 144.7, P = 0.024), and left ventricular (LV) dP/dt max (66.4 ± 90.1, P < 0.001). Change in RVOT gradient was only observed in those with a positive pulmonary vasodilator response to treatment. Treatment with iE&iM did not present adverse effects when compared with a matched case-control group.

CONCLUSIONS

Coadministration of iE&iM in cardiac surgery patients presenting with PH or signs of RV dysfunction is a safe and effective treatment approach in improving RV function. Appearance of a transient increase in RVOT gradient after iE&iM could be useful to predict response to treatment.

Bedside Point-of-Care Ultrasonography in Anesthesiology and Pain Management: A New Trend in Iran: A Narrative Review

: Since the emergence of ultrasonography, many specialists, including anesthesiologists, have become interested in its practices. Technological innovations in portable ultrasonography devices and their quality enable anesthesiologists to use ultrasonography in various medical conditions and improve their diagnostic and therapeutic interventions. This article clarifies the significance of point-of-care ultra-sonography (POCUS) and highlights the challenges ahead. POCUS can help regional anesthesiologists and pain physicians in vascular access, airway management, focused cardiac ultra-sound (FoCUS), lung ultrasound, gastric ultrasound, focus assessment with sonography in trauma (FAST), regional and neuraxial nerve blocks, and acute and chronic pain management. However, similar to any new clinical method, there are challenges to POCUS, especially in developing countries like Iran. These challenges include the need for more budget allocation for medical equipment and portable devices, developing a comprehensive local curriculum and transparent framework to train residents and postgraduates, creating and/or revising university policies, clinical coordination with healthcare networks, and collaboration with healthcare providers. This article expresses the importance and effectiveness of point-of-care sonography performed by anesthesiologists and pain specialists in Iran and highlights the challenges ahead.

New developments in the understanding of right ventricular function in acute care

PURPOSE OF REVIEW

Right ventricular dysfunction has an important impact on the perioperative course of cardiac surgery patients. Recent advances in the detection and monitoring of perioperative right ventricular dysfunction will be reviewed here.

RECENT FINDINGS

The incidence of right ventricular dysfunction in cardiac surgery has been associated with unfavorable outcomes. New evidence supports the use of a pulmonary artery catheter in cardiogenic shock. The possibility to directly measure right ventricular pressure by transducing the pacing port has expanded its use to track changes in right ventricular function and to detect right ventricular outflow tract obstruction. The potential role of myocardial deformation imaging has been raised to detect patients at risk of postoperative complications.

SUMMARY

Perioperative right ventricular function monitoring is based on echocardiographic and extra-cardiac flow evaluation. In addition to imaging modalities, hemodynamic evaluation using various types of pulmonary artery catheters can be achieved to track changes rapidly and quantitatively in right ventricular function perioperatively. These monitoring techniques can be applied during and after surgery to increase the detection rate of right ventricular dysfunction. All this to improve the treatment of patients presenting early signs of right ventricular dysfunction before systemic organ dysfunction ensue.