LITERATURE REVIEWLinda Shore-Lesserson MD

Section Editor

THORACIC ANESTHESIOLOGY

Richardson J, Sabanathan S, Jones J, et al: A pro-spective, randomized comparison of preoperative andcontinuous balanced epidural or paravertebral bu-pivacaine on post-thoracotomy pain, pulmonaryfunction and stress responses. Br J Anaesth 83:387-392, 1999

Paravertebral block is an underused regional technique in manycenters in thoracic surgical patients, yet it avoids some of the seriousside effects inherent in an epidural technique (ie, hypotension, epiduralabscess, or hematoma). This study reports on 100 adult patients ran-domized to receive thoracic epidural bupivacaine or thoracic paraver-tebral bupivacaine as preoperative bolus doses followed by continuousinfusions. All patients also received diclofenac and patient-controlledanalgesia with morphine. The paravertebral group had significantlylower pain scores at rest and with coughing and less morphine patient-controlled analgesia requirements ( p � 0.05). Some evidence indicatedthat lung function was also improved (higher oxygen saturations andless postoperative respiratory morbidity). Areas under the plasma con-centration versus time curves for cortisol and glucose were significantlylower in the paravertebral group (p � 0.05). Side effects (nausea,vomiting, and hypotension) were restricted to the epidural group.

Implication: Paravertebral block provides an effective, possiblysuperior alternative to thoracic epidural analgesia in patients under-going thoracic surgery.

Garutti I, Quintana B, Olmedilla L, et al: Arterialoxygenation during one-lung ventilation: Combinedversus general anesthesia. Anesth Analg 88:494-499,1999

Combined general and thoracic epidural anesthesia (TEA) com-monly is provided in patients undergoing thoracic surgery, but theeffects of TEA on intraoperative pulmonary gas exchange have notbeen studied in a rigorous fashion. The optimal anesthetic managementof patients undergoing thoracotomy for pulmonary resection has notbeen definitely determined. This study reports on 60 lung cancerpatients undergoing elective thoracic surgery and one-lung ventilation(OLV) who were randomized into 2 groups. In 30 patients (generalanesthesia group), fentanyl and propofol anesthesia was used. Another30 patients (TEA group) were anesthetized with propofol and thoracicepidural 0.5% bupivacaine. Arterial oxygen partial pressure valuesduring OLV in the GA group after 15 and 30 minutes were significantlyhigher compared with the TEA group (p � 0.05). Shunt fraction wasincreased in the TEA group during OLV (p � 0.05).

Implication: When compared with general anesthesia alone, TEA isassociated with increased shunt fraction and decreased arterial oxy-genation during OLV.

ECHOCARDIOGRAPHY

Lim HE, Shim WJ, Rhee H, et al: Assessment ofcoronary flow reserve with transthoracic Doppler

echocardiography: Comparison among adenosine,standard-dose dipyridamole, and high-dose dipyrid-amole. J Am Soc Echocardiogr 13:264-270, 2000

Coronary flow reserve (CFR) is usually assessed using coronaryvasodilators and intracoronary Doppler measurements. In 25 consecu-tive patients without significant stenosis of the left anterior descendingcoronary artery, transthoracic echocardiography was used to calculatecoronary flow reserve. The Doppler spectrum of blood flow from thedistal left anterior descending was measured, and coronary vasodilatorresponses to adenosine and dipyridamole were used to calculate CFRand coronary vascular resistive index. Intraobserver variability was4.3% � 3%, and interobserver variability was 5% � 2%. In 20 patients,adenosine induced higher coronary flow velocity than dipyridamole(0.56 mg/kg), which resulted in a higher CFR and lower coronaryvascular resistive index.

Implication: CFR can be estimated using noninvasive methods. Inusing transthoracic echocardiography for this purpose, the coronaryvasodilative effects of adenosine are more potent than those of low-dose dipyridamole.

Bilge M, Eryonucu B, Guler N, et al: Transesoph-ageal echocardiography assessment of left atrial ap-pendage function in untreated systemic hypertensivepatients in sinus rhythm. J Am Soc Echocardiogr13:271-276, 2000

The left atrial appendage (LAA) is important in conditions of cardiacloading. Systemic hypertension decreases left ventricular complianceand may affect LAA function adversely as assessed by the transesoph-ageal echocardiographic parameters LAA area, LAA emptying velocity(LAAEV), left atrium (LA) size, spontaneous echo contrast (SEC), andLA thrombus. These measurements were performed in 46 patients withessential hypertension who were in sinus rhythm and in 16 controlsubjects without hypertension. The LA diameter had a significantcorrelation with diastolic blood pressure (r � 0.69; p � 0.01) and anegative correlation with LAAEV (r � �0.52; p � 0.01). LAAEV wassignificantly lower in the hypertensive patients than in control subjects.SEC was noted in 13 hypertensive patients, and thrombus was found in8. None of the control subjects had SEC or thrombus.

Implication: Systemic hypertension may create a loading stress onthe left atrium that could lead to dysfunction, conditions of thrombusformation, or both.

INTRACORONARY STENTING AND RESTENOSIS

Serruys PW, Foley DP, Hofling B, et al: Carvedilolfor prevention of restenosis after directional coronaryatherectomy: Final results of the European carvedilolatherectomy restenosis (EUROCARE) trial. Circula-tion 101:1512-1518, 2000

Antioxidants have been shown to reduce restenosis rates after an-gioplasty, although the mechanism remains largely speculative. Carve-dilol is a nonselective �-adrenergic receptor blocker that has vasodi-

755Journal of Cardiothoracic and Vascular Anesthesia, Vol 14, No 6 (December), 2000: pp 755-756