The acute effects of pneumonectomy on pulmonary vascular impedance in the dog.

Pulmonary vascular impedance is a measure of the pulsatile characteristic of pressure and flow that occurs in the proximal pulmonary arteries. Pulmonary vascular resistance (PVR) is most influenced by the distal circulation of the lung. This study was performed to evaluate the changes that occurred in pulmonary vascular impedance, as well as in other hemodynamic variables, following pneumonectomy by a closed-chest method in 10 anesthetized dogs. The following observations were made (numbers compare mean values for the 10 dogs before and after pneumonectomy): (1) PVR increased from 447 to 761 dyne sec cm-5 (p = .02); (2) the oscillatory work of the right ventricle increased from 1.23 to 1.76 J/min (p = .006); (3) the mean pulmonary artery pressure increased from 14 to 18.8 mm Hg (p = .0001); and (4) cardiac output and heart rate remained unchanged. Surprisingly, the estimated characteristic impedance (the impedance to oscillatory flow in the proximal bed) did not change significantly (279 to 296 dyne sec cm-5). This observation cannot be explained by the usual lumped compartmental models classically used to characterize the pulmonary vascular bed.

Open versus endoscopic saphenous vein harvesting: wound complications and vein quality.

BACKGROUND: The saphenous vein is an important conduit for coronary artery bypass grafting. Wound complications from traditional open vein harvesting occur often. Minimally invasive endoscopic saphenous vein harvesting may decrease wound complications. Vein quality may be an issue with endoscopic harvesting. METHODS: We reviewed 568 patients who had bypass grafting and saphenous vein harvesting either endoscopic (group A, n = 180) versus open (group B, n = 388). Both groups were demographically similar and management identical. Wound complication was defined by the need for intervention and included lymphocele, hematoma, cellulitis, edema, eschar, and infection. Multiple vein segments were obtained from 8 patients, 4 from each group, and examined histologically. RESULTS: Wound complications were significantly less in group A (9/180, 5%) versus group B (55/388, 14.2%), p value equal to or less than 0.001. Open harvesting (p< or =0.001), diabetes (p< or =0.001), and obesity (p< or =0.02) were risk factors for wound complication by univariate analysis. By multiple logistic analysis, open harvesting (p< or = 0.0007) and diabetes (p< or =0.0001) were independent risk factors for wound infection. Histologic evaluation of vein samples showed that there was no difference between the groups and vascular structural integrity was maintained. CONCLUSIONS: Endoscopic saphenous vein harvesting was associated with fewer wound complications and infections. Vein quality was not adversely effected because of endoscopic harvesting.

A clinical review of patients undergoing resection for pulmonary hamartoma.

Both the radiology and surgery literature mention "popcorn calcification" as a diagnostic aid in identifying pulmonary hamartomas. Nineteen patients underwent resection of pulmonary hamartomas at North Carolina Memorial Hospital between January 1969 and February 1983, representing 1.9 per cent of all thoracotomies performed for pulmonary disease. Of the 19 patients, there were 12 men (63%) and 7 women (37%), and most were asymptomatic. Chest x-ray demonstrated 12 right-sided and 7 left-sided lesions. All masses were located peripherally in the lung parenchyma and in no instance was calcification present. Fourteen wedge resections and 5 lobectomies were performed. Pathologic examination confirmed the absence of calcification; however, in two cases (11%) an associated malignancy was present. There were no operative deaths and only minor postoperative complications. All problems resolved without difficulty. These data show that pulmonary hamartomas are not commonly associated with calcification, and there may be an increased association with carcinoma of the lung. Excision can be performed with minimal morbidity and is necessary to distinguish hamartomas from malignant lesions.

"Pigtail" catheter drainage in thoracic surgery.

Small-bore percutaneous drainage catheters have been used extensively in the management of abdominal disorders and are gaining acceptance in thoracic problems. The records have been reviewed in 44 consecutive patients in whom 53 small-bore catheters were placed for thoracic disease, including empyema, 20; effusion, 9; pneumothorax, 10; lung abscess, 4; and mediastinal cyst, 1. Insertion was performed under fluoroscopy in 88%, computed tomography in 6%, and ultrasonography in 6%. Catheters ranged in size from 6.5F to 12F, but catheter size did not seem to influence outcome (p = 0.6). There was complete resolution of the problem in 75% (33 of 44) of the patients, although 20% of them required more than one catheter. Treatment was successful in all cases of lung abscess. These patients had been previously treated with standard medical therapy for 12 to 53 days without significant improvement in their clinical condition. Patients with empyema composed the largest group treated. Eighty percent (16 of 20) of them had a loculated (LOC) process. The LOC group appeared to have a slightly better success rate than did the non-LOC group (75 versus 50%, p = 0.33). When the catheters failed to resolve the problem (empyema, 6; chylous effusion, 1; malignant effusion, 3; and spontaneous pneumothorax, 1, either operation (9.1%) or a standard thoracostomy tube (13.6%) was required. The complications rate was 20%, but most of these were minor problems including pneumothorax, 5; catheter occlusion 3; fractured catheter, 1; infection, 1; and significant subcutaneous emphysema, 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Sequential, free and Y internal thoracic artery grafts.

The internal thoracic artery (ITA) has excellent durability and its ability to survive for 10 years or more far exceeds the saphenous vein graft (SVG). In an attempt to improve long-term survival from coronary artery bypass grafting (CABG), three or more (up to six) ITA coronary anastomoses have been placed in 718 patients since 1982. Initial flow in the ITA immediately after grafting is critical to the success of the operation. Careful dissection and preparation of the ITA pedicle to prevent injury and spasm, constructing parallel and perpendicular anastomoses so the most proximal portion of the ITA is used for anastomosis and the use of the free right ITA to increase length of graft available are measures employed to increase critical flow. Actuarial survival at 6 years is 92.5% in this group of patients, which includes elderly patients, patients with left ventricular dysfunction and patients undergoing emergency operations.

The use of angiodynography to quantify blood flow in the canine aorta.

Previous attempts to quantify blood flow by means of ultrasound have been hampered by inaccurate diameter measurements and failure to account for the parabolic nature of the cross-sectional velocity profile. Angiodynography (ADG) provides a B-mode image of vessel walls, and the outer flow envelope is constantly monitored to provide phasic diameter measurements throughout the cardiac cycle. Frequency shifts are color-coded to provide a real-time visual display of varying velocity patterns across the vessel lumen throughout the cardiac cycle as well as calculation of average flow velocity and mean blood flow. Simultaneous flow values obtained with ADG were compared with electromagnetic flow probe (EMF) measurements in 12 open-chest dogs. Flow was varied with volume administration and exsanguination, and 201 data points were obtained. The average flow determined by EMF was 2.0 +/- 0.9 L/min compared with 2.04 +/- 0.71 L/min for ADG. The correlation coefficient was 0.88, the y-intercept was close to zero, and the slope approached unity, confirming the ability of ADG to accurately determine volume blood flow rather than merely to establish a flow trend. It is concluded that ADG offers an accurate way of quantifying volume blood flow.