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To the Editor, Providers should be vigilant when planning a neuraxial or peripheral nerve block in patients taking a new medication for idiopathic pulmonary fibrosis (IPF) or systemic sclerosis-associated interstitial lung disease. Nintedanib (Ofev, Boehringer Ingelheim Pharmaceuticals, Ridgefield

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 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.

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 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.

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.

We undertook a prospective laboratory study to examine the effect of head position on the relative positions of the carotid artery and the internal jugular vein (IJV). Volunteers (n = 12) from departmental staff, 18-60 yr of age, who had never undergone cannulation of the IJV underwent imaging of their IJV and carotid artery. With the subject in a 15 degrees Trendelenburg position, two-dimensional ultrasound images of the IJV and the carotid artery were obtained on the left and right sides of the neck at 2 and 4 cm from the clavicle along the lateral border of the sternal head of the sternocleidomastoid muscle at 0 degrees, 40 degrees, and 80 degrees of head rotation from the midline. The percent overlap of the carotid artery and IJV increased significantly at 40 degrees and 80 degrees head rotation to both the right and left (P0.05). Data from 2 and 4 cm above the clavicle did not differ and were pooled. The percent overlap was larger on the left than the right only with 80 degrees of head rotation (P0.05). The increased overlap of carotid artery and IJV with head rotation40 degrees increases the risk of inadvertent puncture of the carotid artery associated with the common occurrence of transfixion of the IJV before it is identified during needle withdrawal. The IJV frequently collapses with needle insertion. This may result in puncture of the posterior wall of the vessel, and thus of the carotid artery when the two vessels overlap. To decrease this risk, the head should be kept in as neutral a position as possible, that is40 degrees rotation, during IJV cannulation.

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° 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.

To evaluate the effects of milrinone on middle cerebral artery blood flow velocity (Vmca) and pulsatility index (PI) during normocapnia and hyperventilation in adults after cardiopulmonary bypass (CPB).A prospective study.University-affiliated hospital and Veterans Affairs Medical Center.Twenty-five adults with left ventricular ejection fraction40% undergoing coronary artery bypass graft surgery.After separation from CPB, using transcranial Doppler ultrasonography, peak and mean Vmca and PI were recorded before and after the administration of 50 microg/kg of milrinone under normocapnia and with hyperventilation.Heart rate, arterial blood pressure, central venous pressure, and cardiac output were documented after each study period. Compared with baseline, milrinone increased peak Vmca by 20%, increased mean Vmca by 19%, and decreased PI by 16% (p0.001). Before the administration of milrinone, hyperventilation decreased peak Vmca by 20%, decreased mean Vmca by 26%, and increased PI by 24% (p0.01). After milrinone administration, hyperventilation also decreased peak Vmca by 22%, decreased mean Vmca by 21%, and increased PI by 19% (p0.01). Milrinone increased cardiac index and decreased mean arterial pressure and systemic vascular resistance (p0.05); however, heart rate and central venous pressure remained unchanged.The administration of milrinone increases cerebral blood flow after CPB most likely as a result of cerebral vasodilation. The response to hyperventilation seems to be partially preserved.

Objective: To identify the incidence of coronary-subclavian steal syndrome in patients undergoing noncardiac surgery. Design: Prospective. Setting: Veterans Affairs Medical Center and university-affiliated medical center. Participants: Adult patients with prior coronary artery bypass graft surgery and documented use of an internal mammary artery. Interventions: Bilateral simultaneous brachial blood pressures were determined noninvasively. The presumptive diagnosis of ipsilateral subclavian artery stenosis and coronary-subclavian steal syndrome was made if the systolic blood pressure differential was >20 mmHg. Measurements and Main Results: The presumptive diagnosis of ipsilateral subclavian artery stenosis based on a blood pressure differential was made in 6 of 86 (5%) patients screened. The diagnosis of coronary-subclavian steal syndrome was confirmed at cardiac catheterization by observing retrograde internal mammary artery flow in 3 patients or lack of internal mammary artery flow in 1 patient (3.4%). All 4 patients with angiographic confirmation had either angina or silent ischemia. Three patients had successful carotid subclavian bypass, and 1 patient refused surgery. Two patients had no evidence of myocardial ischemia and underwent their planned procedure without incident. Conclusion: Coronary-subclavian steal syndrome occurs with relative frequency in noncardiac surgery patients with prior coronary artery bypass graft surgery using internal mammary artery conduits. Bilateral blood pressure measurements should be routinely performed during the preoperative evaluation. A pressure differential >20 mmHg should suggest the possibility of coronary-subclavian steal syndrome. Copyright © 2001 by W.B. Saunders Company

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.

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 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.