Cheri A. Sulek

cerebral Microembolism Diagnosed by Transcranial Doppler during Total Knee Arthroplasty : Correlation with Transesophageal Echocardiography

BACKGROUND Tourniquet deflation following total knee arthroplasty (TKA) frequently results in release of emboli into the pulmonary circulation. Small emboli may gain access to the systemic circulation via a transpulmonary route or through a patent foramen ovale. This study examined the incidence of cerebral microembolism after tourniquet release by transcranial Doppler (TCD) ultrasonography and its correlation with echogenic material detected in the left atrium. METHODS Twenty-two adult patients (9 men, 13 women) undergoing TKA were studied with simultaneous TCD ultrasonography and transesophageal echocardiography. Data were recorded after anesthesia induction and tourniquet inflation and during tourniquet deflation. Emboli counts were performed manually off-line. Echogenic material in the left atrium was qualitatively assessed and correlated with TCD data. Patients were examined postoperatively for focal neurologic deficits. RESULTS Fifteen patients had unilateral TKA (six left, nine right) and seven had bilateral TKA. Cerebral emboli were detected in 9 of 15 patients (60%) with unilateral TKA and in 4 of 7 patients (57%) with bilateral TKA. Echogenic material was identified in the left atrium in eight patients (two through a patent foramen ovale and six from the pulmonary veins). Emboli counts were significantly higher in patients with bilateral TKA compared with those with unilateral TKA (P<0.05). Duration of tourniquet time in patients with emboli was longer only during bilateral TKA (P<0.05). All patients with echogenic material in the left atrium detected by transesophageal echocardiography had emboli as assessed by TCD ultrasonography. No focal neurologic deficits were identified. CONCLUSIONS Cerebral microembolism occurs frequently during tourniquet release, even in the absence of a patient foramen ovale. This passage most likely occurs through the pulmonary capillaries or the opening of recruitable pulmonary vessels.

Cross-sectional area of the right and left internal jugular veins.

OBJECTIVE To compare the cross-sectional area (CSA) of the right internal jugular vein (RIJV) with the left internal jugular vein (LIJV) using two-dimensional ultrasound and to measure the response to the Valsalva maneuver in both the supine and Trendelenburg positions. DESIGN Prospective and randomized. SETTING University-affiliated hospital. PARTICIPANTS Fifty healthy adult volunteers. INTERVENTIONS The CSA of both the RIJV and LIJV was measured with a 5-MHz, two-dimensional surface transducer before and during a 10-second Valsalva maneuver with the subjects in the supine position, and then with the subjects in a 10 degree Trendelenburg tilt. MEASUREMENTS AND MAIN RESULTS After the baseline measurements were performed, the subjects were divided into two groups based on the CSA of the RIJV and LIJV. Group 1 had an LIJV CSA equal to or greater than that of the RIJV (n = 10) and group 2 had an LIJV CSA less than that of the RIJV (n = 40). Of the latter 40 patients, 17 (34%) had an LIJV CSA less than 50% of that of the RIJV. In both groups, the CSA of both veins increased significantly with the Valsalva maneuver, Trendelenburg tilt, and both maneuvers combined. CONCLUSION The findings suggest that in one third of adults (34%), the LIJV is significantly smaller compared with the RIJV and, combined with operator inexperience, may influence the success rate and risk for complications. Thus, the use of ultrasound and maneuvers that increase CSA is suggested during LIJV cannulation.

A randomized study of left versus right internal jugular vein cannulation in adults

STUDY OBJECTIVE To compare the success rate and incidence of complications of right internal jugular vein (RIJV) versus left internal jugular vein (LIJV) cannulation using external landmarks or surface ultrasound guidance. DESIGN Prospective randomized study. SETTING Operating room of a university-affiliated hospital. PATIENTS 120 adult patients scheduled for elective abdominal, vascular, or cardiothoracic procedures with general anesthesia and mechanical ventilation in whom central venous cannulation was clinically indicated. INTERVENTIONS Patients were randomized to four groups for RIJV cannulation using the landmark approach (Group 1) or surface ultrasound (Group 2) versus LIJV cannulation with the landmark approach (Group 3) or ultrasound (Group 4). MEASUREMENTS AND MAIN RESULTS The data collected included time from first puncture to guidewire insertion, number of attempts, and associated complications. If conversion to the ultrasound technique was required, the number of crossover patients and reasons for failure were recorded. Cannulation of the LIJV was more time consuming; it required more attempts; and it was associated with a greater number of complications when compared to the right side (p < 0.05). CONCLUSIONS Left IJV cannulation is more time consuming than RIJV cannulation and is associated with a higher incidence of complications. The use of ultrasound improves success rate and decreases the number of complications during IJV cannulation.

Differential effects of right versus left stellate ganglion block on left ventricular function in humans: An echocardiographic analysis

STUDY OBJECTIVES To evaluate the effects of unilateral stellate ganglion blockade on left ventricular function. DESIGN Prospective cohort of patients with chronic regional pain syndrome type I and II of the upper extremity requiring therapeutic stellate ganglion blockade. SETTING University-affiliated hospital. PATIENTS Fifteen adult ASA physical status I and II patients with the diagnosis of chronic regional pain syndrome type I and II of the arm were studied. Right stellate ganglion block was performed in nine subjects and a left in six. INTERVENTIONS Stellate ganglion block was performed with 10 mL of 1% plain Xylocaine. Transthoracic echocardiograms were performed immediately prior and 30 min following the block. MEASUREMENTS Heart rate and blood pressure were monitored at regular intervals. Global systolic function was determined by calculating ejection fraction. Regional systolic motion was evaluated on the short axis and four-chamber views using the American Society of Echocardiography criteria. Diastolic function was assessed with pulsed-wave Doppler of the left ventricular outflow tract and the mitral valve. Data collected included isovolumic relaxation time and early and atrial velocity patterns. MAIN RESULTS A successful stellate ganglion block was achieved in all patients. Blood pressure and heart rate were not significantly different during data collection. Patients who underwent a right stellate ganglion block showed no significant differences in systolic or diastolic function. Following a left stellate ganglion block, global and regional systolic function remained unchanged. Isovolumic relaxation time was increased but did not reach statistical significance (80 +/- 13 ms to 88 +/- 9 ms; p = 0.09). Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV) were significantly increased (LVEDV from 73 +/- 9 mL to 100 +/- 9 mL, p < 0.02; LVESV from 31 +/- 4 mL to 37 +/- 4 mL, p < 0.03). CONCLUSIONS In patients without cardiovascular disease, unilateral denervation of the left ventricle after stellate ganglion block produces no clinical deleterious effects on left ventricular function.

Angina as an Indication for Noncardiac Surgery: The Case of the Coronary-Subclavian Steal Syndrome

THE presence of angina in patients scheduled for noncardiac surgery is considered a risk factor for perioperative cardiovascular complications. 1 Myocardial revascularization is an effective treatment for angina; when performed before noncardiac surgery, it decreases cardiac complications compared with medical therapy Patients who undergo myocardial revascularization with internal mammary artery (IMA) grafting demonstrate longer survival and higher resolution of symptomatology when compared with patients with vein grafts. 4-6 The most common practice is to graft the distal end of the IMA to an epicardial coronary artery to allow antegrade flow to travel from the subclavian artery toward the heart. However, if stenosis of the subclavian artery proximal to the take off of the IMA is present, angina may occur as a result of coronary-subclavian steal. 7 If the stenosis includes the carotid artery, then symptoms of cerebral ischemia can occur concurrently, Here, we report the successful perioperative treatment of two patients diagnosed with unstable angina due to coronary-subclavian steal syndrome.

Use of near-infrared spectroscopy to monitor cerebral oxygenation during coronary artery bypass surgery in a patient with bilateral internal carotid artery occlusion

R EGIONAL CEREBRAL OXYGEN SATURATION (RSO2) depends on the balance between regional oxygen delivery and consumption. The factors that alter this relationship include global and regional cerebral blood flow, hemoglobin concentration, arterial oxygen saturation, and regional cerebral oxygen consumption. Near-infrared spectroscopy (NIRS) is a novel method used to determine RSO2 .1 This technique has been used predominantly in infants and children to determine cerebral oxygenation during extracorporeal membrane oxygenation. 2 Its application has been expanded for use during carotid endarterectomy and in operations involving cardiopulmonary bypass (CPB). 3,4 By providing continuous RSO2 monitoring, this technique may allow detection of changes that signal early cerebral hypoxia and thus allow for prompt therapeutic intervention to minimize risk of neurologic injury. This case report describes the use of continuous cerebral oximetry during coronary artery bypass graft (CABG) surgery in a patient with bilateral internal carotid artery occlusion.

Acromegaly discovered during a routine out-patient surgical procedure: a case report

BackgroundAcromegaly is a rare syndrome in which there is unregulated hypersecretion of growth hormone. The anesthetic management of patients with this disorder is particularly challenging due to pre-existing cardiovascular and respiratory dysfunction, as well as recognized difficulties with airway management. Because of the insidious progression of the disease and the presence of nonspecific signs and symptoms, diagnosis is often made late when characteristic acromegalic features become apparent.Case presentationWe report the management of a 35-year-old African American man with previously undiagnosed acromegaly, who underwent a general anesthetic for same day surgery. Subtle physical features and difficult endotracheal intubation raised our suspicion for the diagnosis of acromegaly. Following an uncomplicated postoperative course he underwent workup for the disease, which was confirmed. In addition, brain magnetic resonance imaging showed a pituitary adenoma. A subsequent transsphenoidal hypophysectomy was performed successfully.ConclusionsThis case underscores the notable absence of recognizing the clinical presentation of acromegaly in this patient by his primary care physician, and the value of thorough history taking, vigilance, and observation in making a new diagnosis that has the potential to alter a patient’s health care and mitigate impending morbidity and/or mortality.