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Biomedical subjects

D J Dries

Publications and source records attributed to D J Dries.

54 records · Page 3Linked to original sources

Hemodynamic compromise associated with air trapping following coronary artery bypass surgery.

Cardiovascular collapse due to pulmonary hyperinflation was noted in a patient with chronic obstructive pulmonary disease following median sternotomy for cardiac surgery. Treatment included bronchodilator therapy to reduce airway obstruction, limitation of minute ventilation, and increasing time available for exhalation. High inspiratory flow rates and expiratory retard may be beneficial.

Acute Disease↗

Effect of cardiac output on gas exchange in one-lung atelectasis.

To evaluate the effect of administration of dobutamine on gas exchange in patients with one-lung atelectasis during pneumonectomy, ten patients with normal pulmonary function and localized carcinoma of the lung were studied during pulmonary resection. With each patient in the lateral decubitus position, hemodynamic profiles and oxygen transport data were recorded before and after administration of dobutamine at 5 micrograms/kg/min. Patients were ventilated with one-lung anesthesia and administration of 100 percent oxygen. With infusion of dobutamine, the heart rate, cardiac index, and LVSWI significantly increased. Mean arterial pressure increased while PAP fell. Systemic and pulmonary vascular resistance also declined. Arterial oxygenization and delivery improved, while oxygen uptake was unchanged. Pulmonary shunt fraction was significantly reduced. While the mechanism for shunt reduction in our patients is unclear, operative factors may include pulmonary vasodilation with dobutamine inhibition of HPV. The negative impact of reduced HPV may have been lessened by gravitational distribution of blood flow and dobutamine-mediated reduction in PAP in our patients.

Aged↗

Effect of opening the pericardium on right ventricular hemodynamics during cardiac surgery.

The impact of the pericardium on right ventricular performance in the presence of normal filling pressures was evaluated using a rapid response RVEF thermodilution pulmonary artery catheter and TEE. In eight patients with normal right coronary arteries undergoing coronary artery bypass surgery, hemodynamic measurements revealed increased right ventricular end-diastolic and end-systolic volumes with diminished RVEF after opening the pericardium. In eight additional patients with right coronary artery disease, directionally similar changes in right ventricular volume were seen. Ejection fraction, however, was unchanged possibly due to altered right ventricular compliance. Echocardiogram evaluation of right ventricular area changes in patients with compromised right coronary systems corresponded to ejection fraction determinations obtained with thermodilution technique.

Cardiac Surgical Procedures↗

Permeability pulmonary edema following lung resection.

The etiology of edema associated with pulmonary resection was investigated in five patients during the immediate postoperative period. Three patients received pneumonectomy while two patients had one lobe resected. All patients suffered from severe respiratory distress and had x-ray evidence of diffuse interstitial pulmonary edema within 12 hours of surgery. Hemodynamic data were obtained with radial and pulmonary artery catheters. Edema fluid was obtained along with blood samples for simultaneous determination of protein and albumin content. All patients studied had normal or high cardiac output, normal cardiac filling pressures, and edema fluid protein to serum protein ratio of 0.6 or greater suggestive of permeability changes contributing to edema fluid accumulation. Calculated shunt fraction exceeded 25 percent in all patients. Pulmonary edema has been noted in patients following pulmonary resection in the early postoperative period. In patients reviewed here, two factors appeared to be significant. First is an increase in pulmonary capillary pressure associated with passage of a normal to high cardiac output in a reduced volume pulmonary vascular bed. The second factor, as demonstrated by protein content in the edema fluid, is injury to the alveolar capillary membrane.

Blood Proteins↗

Calcitonin gene-related peptide levels are elevated in patients with sepsis.

Calcitonin gene-related peptide (CGRP), an endogenous vasoactive peptide encoded by the calcitonin gene in nerve cells, is distributed throughout the cardiovascular system and is a potent vasodilator. Plasma levels of CGRP have been elevated in animal models with sepsis. This study was designed to determine whether plasma CGRP levels are elevated in patients with sepsis and perhaps contribute to the hyperdynamic cardiovascular state in sepsis. Plasma CGRP levels were obtained from normal healthy volunteers and from patients with sepsis. Volunteers were afebrile and had normal pulse and blood pressure. Patients with sepsis were selected according to the following criteria: (1) temperature higher than 38.5 degrees C, (2) white blood count greater than 14,000/ml, (3) positive blood culture of bacterial organisms, (4) hemodynamic parameters consistent with hyperdynamic sepsis, and (5) negative history of thyroid or other endocrine abnormalities. CGRP was extracted and assayed by radioimmunoassay for iodine 125-labeled human CGRP. In patients with sepsis, the cardiac index was 5.4 +/- 0.5 L/min/m2 (normal, 3.0); systemic vascular resistance was 7.1 +/- 0.5 mm Hg/L/min (normal, 16); oxygen delivery was 1496 +/- 137 ml/min (normal, 1000). Plasma CGRP levels were significantly elevated in the patients with sepsis, 14.9 +/- 3.2 pg/ml, compared to plasma CGRP levels in control volunteers, 2.0 +/- 0.3 pg/ml (p less than 0.0005). These elevated levels of CGRP may contribute to the decreased vascular resistance and increased cardiac output in the hyperdynamic septic state.

Adult↗

Endoscopic laser resection of atherosclerotic plaque in a live animal model. A preliminary report on some technical difficulties.

This study was designed to determine whether laser energy could be used effectively to resect atherosclerotic plaque through an endoscope in a live animal model. Twelve adult Yorkshire swine with infrarenal aortic atherosclerosis had a 2.5 mm and/or 3.2 mm diameter fiberscope passed into the aorta from the femoral artery after proximal aortic balloon occlusion. Endoscopic argon laser resection of the atherosclerotic plaque was then attempted in eight pigs with an argon laser fiber (60 to 400 microns). We were able to visualize the raised atherosclerotic plaque in all 12 pigs with the larger 3.2 mm diameter fiberscope, which was easily passed into the aortoiliac system from the 4 mm diameter femoral vessel. The articulating end feature enhanced maneuverability within the lumen and allowed laser fiber direction. The 2.5 mm endoscope did not allow adequate visualization in any pig since the vessel could not be cleared of blood. The 2.5 mm endoscope was also passed from the femoral artery distally into the hind limb and still did not allow adequate visualization of the vessel wall because of persistent luminal blood. The 3.2 mm endoscope enabled vessel wall visualization distal to the femoral artery when the proximal artery was occluded. No aortas were grossly perforated by the laser energy. In all pigs undergoing endoscopic laser resection, raised plaques were removed both grossly and histologically, although the plaque edges were carbonized and frayed as well as vaporized. With the small spot size of the argon fiber, channels were drilled through plaque, frequently with incomplete recanalization of the lumen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

The economic implications of infection in cardiac surgery.

To assess the economic impact of infection, the records of 496 patients aged 18 to 82 years (mean, 61 years) undergoing open-heart operations in 1981 and 1982 were reviewed, and the costs (length of stay, hospital charges, pharmacy charges) were compared for matched pairs of patients with and without infection who had coronary artery bypass grafting (CABG) procedures. Patients received a 5-day regimen of prophylactic cephalosporin. Operative site infections occurred within 6 months of operation in 17 patients (3.4%), urinary tract infections in 9 (1.8%), and pulmonary infections in 6 (1.2%). Early and late mortality was each 2%. No deaths were infection related, and no postoperative bacterial endocarditis occurred (minimum one-year follow-up). For the matched CABG patient in whom a postoperative wound infection developed, the average length of hospital stay was 16.7 days longer and the average hospital bill was $8,118 greater, with the average cost to the hospital $6,605 greater.

Adolescent↗

Responses of atherosclerotic aorta to argon laser.

Lasers have been advocated to resect atherosclerotic plaques in the cardiovascular system, yet little information is available regarding the effects of laser on the range of occlusive lesions seen in the peripheral arterial tree. This study was conducted to assess the risk of perforation in human cadaveric aorta involved with variable degrees of atherosclerosis. Ten fresh segments of atherosclerotic human aorta were graded for extent of atherosclerosis, then subjected to argon laser energy within 48 hours. Using air as the conduction medium and with the fiber tip 2 or 5 mm from the vessel wall, the argon laser was applied to matched calcified and non-calcified arteries at 3.0-7.0 W and 10.0-13.5 W with energy density identical for matched pairs. Results were compared among segments which were normal in appearance or had only fatty streaks grossly with those with gross regional wall calcification. The mean penetration time (T) for calcified and non-calcified lesions at low and high power outputs was compared. (table; see text) Mean time to perforation and range of time necessary to produce perforation were greater in calcified than non-calcified segments at all power levels employed. These data suggest that atherosclerotic lesions vary in their response to argon laser. The presence of calcium may preclude resection of some plaques and protect against wall perforation.

Aortic Diseases↗

Detection of acute synthetic vascular graft infection with 111In-labeled leukocyte scanning: an animal study.

Synthetic vascular graft infection is characterized by late diagnosis due to indolent and nonspecific symptoms. Indium-111-labeled leukocyte imaging holds promise as a diagnostic tool to identify vascular graft infection, but reported data on its accuracy are somewhat sparse and conflicting. In this study, 13 mongrel dogs received Dacron aortic interposition grafts. Seven grafts were contaminated at the time of surgery by topical ATCC Staphylococcus aureus concentrated at 10(8) organisms/ml. Six control animals received no graft contamination. All infected animals were sacrificed on the second postoperative day after 111In leukocyte scanning. The results showed a sensitivity of 71%, specificity of 100%, and accuracy of 85% for the 111In leukocyte study in detecting early graft infections; false-positive leukocyte scans in the early postoperative period were not a problem as has been reported by others. These data indicate that leukocyte scanning for graft infection detection is likely to be clinically valuable.

Animals↗

Indium 111-labeled leukocyte scanning for detection of prosthetic vascular graft infection.

Recent animal and human studies have suggested that positive indium 111-labeled leukocyte scans may help establish the diagnosis of vascular graft infection; however, there is little information available about the predictive value of both positive and negative leukocyte scans in larger groups of patients. In this study 31 indium 111 leukocyte scans were performed prior to definitive treatment in 21 patients with suspected vascular graft infections. Patients with more than one leukocyte scan performed had either anatomically distinct sites of infection or rescanning of a potentially infected site after definitive treatment. Scans were performed according to the method of Baker et al., attaching 500 muCi of indium 111 to leukocytes with imaging 24 hours later. All patients with positive scans underwent surgical exploration of the area of leukocyte accumulation, with documentation of purulence and culture of the graft. Patients with negative scans were treated as if scan results were indeterminate and underwent surgical exploration for usual clinical indications; if no exploration was performed, the patient was followed up closely for at least 1 year. Twelve of 12 positive scans showed purulence or culture evidence of infection with three different organisms; in 15 instances of negative scans, two operations were performed with one infection noted, whereas no patient without surgery has had a graft infection at 10 months follow-up. In addition to localizing graft infections, two scans demonstrated a nonvascular site of infection. Positive scans also helped determine the extent of infection along the graft, allowing better planning of the surgical procedure. These results indicate that indium 111-labeled leukocyte scans help document and localize prosthetic vascular graft infections.

Aged↗

Acute effects of argon laser on human atherosclerotic plaque.

Although the laser has been demonstrated to vaporize coronary artery plaque, there is little information about its ability to resect or vaporize the range of plaques present in peripheral vessels. This study attempts to determine the ability of the argon laser to resect all grades of atherosclerotic plaque, the risk of perforation during plaque resection, the effects on surrounding arteries, and the effect of different transmission media (air, saline solution, and blood) on the delivery of laser energy to the vessel. Seventy-five adult human cadaveric aortic specimens with a range of atherosclerosis from grossly normal artery to extensive calcification with ulceration were exposed to variable energy densities (200 to greater than 20,000 J/cm2) within 48 hours of harvesting. Specimens were examined grossly for the visual effects of laser and microscopically after preparation with hematoxylin-eosin, trichrome, and/or Verhoeff's elastin stains. Our results indicate that normal arteries and noncalcified plaques absorb laser energy and are vaporized. As the atherosclerosis becomes more complex with calcification, calcified regions are not vaporized and cannot be resected. In normal arteries and noncalcified plaque, perforation times were less than 5 seconds. Where palpable calcification was present in atherosclerotic lesions, average perforation time was doubled. In some vessels areas of calcification prevented wall perforation, but areas of subintimal hemorrhage perforated rapidly because of the selective absorption of laser energy by the red color of hemorrhagic tissue. These results remain the same when saline solution is used as a transmission media, although the amount of energy required to achieve the effects is increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Recent progress in advanced cardiac life support.

The revised guidelines for advanced cardiac life support (ACLS) from the American Heart Association are anticipated in the fall of 2000. Although dramatic changes in the approach to adult basic and ACLS are not anticipated, several controversies and new drugs on the horizon may radically change our approach to emergent cardiac resuscitation. This article features some of the evolving thinking on the emergent treatment of the adult with ventricular fibrillation or ventricular tachycardia, the critical rhythms seen in most cases of acute cardiac distress. Approaches to airway therapy drug administration and new agents also are described.

Adult↗

Comparative analysis of bedside and operating room tracheostomies in critically ill patients with burns.

The objective of this study was to demonstrate that bedside burn intensive care unit tracheostomy is a safe and cost-effective procedure and has advantages over operating room tracheostomy. The charts of all patients who underwent tracheostomies in the burn unit between January 1990 and September 1993 were reviewed retrospectively. All tracheostomies were performed by residents in their second to fourth postgraduate years. The identical operating room technique was used for all bedside procedures including complete instrument tray, electrocautery, and adequate lighting. Standard tracheostomies were routinely performed at the bedside instead of the operating room in an attempt to deal with an increasing number of critically ill patients with burns requiring operating room surgical procedures. No patient-specific criteria were used to determine whether bedside or operating room tracheostomy would be performed. Charges for bedside intensive care unit and operating room tracheostomy were compared. Group t test and chi-square analysis were used with significance set at p < 0.05. Forty-three tracheostomies were performed in the 45-month period reviewed. Twenty-five tracheostomies performed in the operating room were compared with the 18 tracheostomies performed at the bedside in the burn intensive care unit. No statistical difference existed in age, sex, mean total body surface area percent burned, mean inspired oxygen, mean positive end expiratory pressure, mean pretracheostomy intubated days, presence of inhalation injury, or complication rate between groups. The average combined cost for operating room and anesthesia was $1740 per tracheostomy performed in the operating room. No charge was given to the patient for a bedside tracheostomy apart from the surgeon's fee and tracheostomy tube.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Neutrophil recruitment after remote scald injury.

Thermal injury is one trigger for pulmonary neutrophil recruitment. This article describes the time course of neutrophil recruitment after scald injury. Mice aged 8 to 10 weeks were anesthetized and subjected to 15% topical scald injury. Animals were put to death at 6 hours, 24 hours, 3 days, and 7 days after injury, and the pulmonary tissue harvested for staining with hematoxylin and eosin and neutrophil esterase. Cell counts for neutrophil accumulation were obtained. Control animals were handled in a comparable manner apart from the scald injury. Animals killed at 6 hours demonstrated significant neutrophil recruitment relative to the control. This difference had resolved at 24 hours. Animals killed at 3 and 7 days again demonstrated neutrophil accumulation despite normal behavior and absence of weight change from the control. Quantitative cultures of burn wounds failed to disclose infection. Scald injury was associated with significant pulmonary neutrophil recruitment that resolved at 24 hours. The presence of an untreated wound was associated with neutrophil recruitment beyond 24 hours despite outward normal behavior.

Analysis of Variance↗

Differential neutrophil traffic in gut and lung after scald injury.

Neutrophil recruitment to the lung after thermal injury has been reported by various laboratories. Changes in neutrophil populations in the gut and lung have not been examined simultaneously after burn injury. Mice aged 8 to 10 weeks were anesthetized and subjected to 15% topical scald injury. Animals were sacrificed at 30 minutes and 1, 2, 4, 8, 16, and 32 hours after injury with harvesting of terminal ileum and lung for myeloperoxidase (MPO) assay. Lungs were evaluated after bronchoalveolar lavage and lavage of the vascular bed to remove neutrophils in these compartments. Myeloperoxidase activity was compared between groups of sham-injured and burned animals. Although pulmonary neutrophil recruitment was obvious after scald burn; in the ileum, burned animals showed diminished MPO activity. Histology and bronchoalveolar lavage revealed no evidence of gross organ injury apart from obvious changes in cellular content in the lung. Thermal injury is associated with differential neutrophil movement in the lung and the gut in this model. Pulmonary neutrophil recruitment is confirmed, whereas the gut seems to lose neutrophils as indicated by diminished MPO activity in the initial hours after dorsal scald injury.

Animals↗