Georges Desjardins

Extracardiac Signs of Fluid Overload in the Critically Ill Cardiac Patient: A Focused Evaluation Using Bedside Ultrasound

Fluid balance management is of great importance in the critically ill cardiac patient. Although intravenous fluids are a cornerstone therapy in the management of unstable patients, excessive administration coupled with cardiac dysfunction leads to elevation in central venous pressure and end-organ venous congestion. Fluid overload is known to have a detrimental effect on organ function and is responsible for significant morbidity in critically ill patients. Multisystem bedside point of care ultrasound imaging can be used to assess signs of fluid overload and venous congestion in critically ill patients. In this review we describe the ultrasonographic extracardiac signs of fluid overload and how they can be used to complement clinical evaluation to individualize patient management.

Intratracheal Milrinone Bolus Administration During Acute Right Ventricular Dysfunction After Cardiopulmonary Bypass

OBJECTIVE To evaluate intratracheal milrinone (tMil) administration for rapid treatment of right ventricular (RV) dysfunction as a novel route after cardiopulmonary bypass. DESIGN Retrospective analysis. SETTING Single-center study. PARTICIPANTS The study comprised 7 patients undergoing cardiac surgery who exhibited acute RV dysfunction after cardiopulmonary bypass. INTERVENTIONS After difficult weaning caused by cardiopulmonary bypass-induced acute RV dysfunction, milrinone was administered as a 5-mg bolus inside the endotracheal tube. MEASUREMENTS AND MAIN RESULTS RV function improvement, as indicated by decreasing pulmonary artery pressure and changes of RV waveforms, was observed in all 7 patients. Adverse effects of tMil included dynamic RV outflow tract obstruction (2 patients) and a decrease in systemic mean arterial pressure (1 patient). CONCLUSIONS tMil may be an effective, rapid, and easily applicable therapeutic alternative to inhaled milrinone for the treatment of acute RV failure during cardiac surgery. However, sufficiently powered clinical trials are needed to confirm these findings.

Risk Factors for Radial-to-Femoral Artery Pressure Gradient in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVE To identify risk factors associated with radial-to-femoral pressure gradient during cardiac surgery with cardiopulmonary bypass (CPB). DESIGN This is a retrospective, observational study. SETTING Single specialized cardiothoracic hospital in Montreal, Canada. PARTICIPANTS Consecutive patients that underwent heart surgery with CPB between 2005 and 2015 (n = 435). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS A radial-to-femoral pressure gradient occurred in 146 patients of the 435 patients (34%). Based on the 10,000 bootstrap samples, simple logistic regression models identified the 17 most commonly significant variables across the bootstrap runs. Using these variables, a backward multiple logistic model was performed on the original sample and identified the following independent variables: body surface area (m2) (odds ratio [OR] 0.08, 95% confidence interval [CI] 0.030-0.232), clamping time (minutes) (OR 1.01, 95% CI 1.007-1.018), fluid balance (for 1 liter) (OR 0.81, 95% CI 0.669-0.976), and preoperative hypertension (OR 1.801, 95% CI 1.131-2.868). CONCLUSION A radial-to-femoral pressure gradient occurs in 34% of patients during cardiac surgery. Patients at risk seem to be of smaller stature, hypertensive, and undergo longer and more complex surgeries.

Transcranial Doppler monitoring guided by cranial two-dimensional ultrasonography

To the Editor, Transcranial Doppler (TCD) imaging was introduced in 1982 as a noninvasive tool to evaluate the velocity of blood flow in the basal cerebral arteries. Since then, TCD has been used in a wide variety of situations, including detection of vasospasm after subarachnoid hemorrhage, finding microemboli during cardiac surgery, and intracranial pressure monitoring. Transcranial Doppler uses low frequency (2 MHz) focused pulsed waves to insonate major cerebral vessels. The red blood cell velocity can be calculated by integrating the emitted and reflected frequencies along with the angle subtended by the respective ultrasonic beam and blood flow directions. Transcranial Doppler monitoring can be easily performed through the temporal window for the arteries of the circle of Willis, submandibular window for the distal internal carotid artery, transorbital window for the ophthalmic artery, and suboccipital window for the vertebral and basilar arteries. The skull is composed of two layers of compact bone separated by a porous diploë layer that allows propagation of ultrasound waves by creating an acoustic interface. Nevertheless, in up to 38% of patients, Doppler signals cannot be acquired because of an inadequate temporal bone acoustic window. Blind placement of a TCD probe can be time consuming, and an inadequate signal might result from an insufficient temporal bone window. The use of two-dimensional (2D) cranial ultrasonography has the potential to facilitate localization of the temporal acoustic window prior to TCD probe placement. The technique involves localizing the temporal acoustic window as the thinner part of the temporal bone just above the zygomatic arch (Figure). This area can be located either in the anterior part of the temporal bone close to the vertical portion of the zygomatic bone or, more frequently, posteriorly and close to the pinna of the ear. Any transthoracic or handheld low frequency transducer probe (1-2 MHz) can be used by directing the marker on the probe toward the occiput. The gain and depth (14-18 cm) are adjusted to localize the bony structures. The contralateral cranial bone is first located in the far field, and in the mid-field region, the petrous ridge can be identified posteriorly and the sphenoid wing anteriorly. The carotid siphon and foramen lacerum can be localized anteriorly. The cerebral falx and cerebral peduncle can be localized in the middle of the field with the mesencephalic brainstem (appearing as a butterfly shape surrounded by the echogenic basal cisterns) in the horizontal axial plane parallel to the orbitomeatal line. Doppler imaging (scale 24 cm sec) allows identification of the major vascular structures. Depth and direction of flow are the main characteristics of the Doppler signal that help to differentiate the various vessels. The identification of the vascular structures usually takes less than one minute. Transcranial Doppler is then positioned and adjusted. Electronic supplementary material The online version of this article (doi:10.1007/s12630-017-0898-9) contains supplementary material, which is available to authorized users.

Successful Repair of a Bicuspid Pulmonary Autograft Valve Causing Early Insufficiency After a Ross Procedure

The Ross procedure is an excellent option in terms of long-term outcomes for young patients requiring aortic valve replacement. We report the case of a 49-year-old woman who presented with worsening dyspnea and episodes of presyncope in the context of a patient-prosthesis mismatch, 13 years after mechanical aortic valve replacement. She underwent a Ross procedure despite the pulmonary valve being bicuspid at intraoperative examination. Following implantation, the autograft valve showed an eccentric jet of regurgitation requiring bicuspid valve repair. To our knowledge, this is the first reported case of successful repair of a bicuspid pulmonary autograft valve.

Perioperative Right Ventricular Pressure Monitoring in Cardiac Surgery

Right ventricular (RV) dysfunction is a cause of increased morbidity and mortality in both cardiac surgery and noncardiac surgery and in the intensive care unit. Early diagnosis of this condition still poses a challenge. The diagnosis of RV dysfunction traditionally is based on a combination of echocardiography, hemodynamic measurements, and clinical symptoms. This review describes the method of using RV pressure waveform analysis to diagnose and grade the severity of RV dysfunction. The authors describe the technique, optimal use, and pitfalls of this method, which has been used at the Montreal Heart Institute since 2002, and review the current literature on this method. The RV pressure waveform is obtained using a pulmonary artery catheter with the capability of measuring RV pressure by connecting a pressure transducer to the pacemaker port. The authors describe how RV pressure waveform analysis can facilitate the diagnosis of systolic and diastolic RV dysfunction, the evaluation of RV-arterial coupling, and help diagnose RV outflow tract obstruction. RV pressure waveform analysis also can be used to guide pharmacologic treatment and fluid resuscitation strategies for RV dysfunction.