Video-assisted thoracic surgical techniques in the diagnosis and management of pericardial effusion in patients with advanced lung cancer.
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Cardiac Tamponade↗
Biomedical subjects
G S Aldea
Publications and source records attributed to G S Aldea.
Delayed perforation of the esophagus by a closed thoracostomy tube.
We report on a previously undocumented complication of a trocar-free thoracostomy tube--delayed perforation of a normal esophagus. The complication presented clinically with fever and copious enteric drainage four days after thoracostomy tube insertion. Diagnosis was established by a contrast study of the esophagus. Retrospectively, the postinsertion chest radiograph showed the offending thoracostomy tube tip impinging on the posterior mediastinum, displacing an indwelling nasogastric tube. Early recognition and repositioning of the thoracostomy tube is the key in preventing this rare but serious complication.
Adult↗
Chronic tension pneumothorax mimicking tension bullae. Use of video-assisted thoracoscopy for diagnosis.
A 48-year-old patient had a lucent right hemithorax and marked mediastinal shift of unknown duration that appeared on a chest radiograph. He was unchanged symptomatically from his baseline status. Video-assisted thoracoscopy was used to distinguish between tension from a giant bulla and a chronic tension pneumothorax.
Chronic Disease↗
Directed atraumatic coronary sinus cannulation for retrograde cardioplegia administration.
A simple method of coronary sinus cannulation for retrograde cardioplegia administration is described that reduces cardiac manipulation. Intraoperative transesophageal echocardiography is used to direct atraumatic coronary sinus cannulation, confirm the depth of insertion of the cannula tip in relation to the ostium, and reduce overall cannulation time.
Cardiac Catheterization↗
Does systolic subepicardial perfusion come from retrograde subendocardial flow?
To examine the influence of cardiac contraction on systolic coronary flow and transmural blood flow distribution, we measured phasic blood flow velocity in distal extramural coronary arteries by Doppler velocimeter and regional myocardial blood flow by radiolabeled microspheres while the heart was beating and during prolonged diastoles in 12 dogs. A servo-controlled coronary perfusion circuit allowed mean coronary pressure to be selected and maintained during beating and diastolic conditions. In epicardial arteries just proximal to their entrance into the myocardium, blood flow was either negligible or reverse in direction during systole. When the heart was beating, subepicardial blood flow was 24.2 +/- 12.3% higher than during asystole (5.05 +/- 0.91 and 4.11 +/- 0.79 ml.min-1.g-1 for beating and prolonged diastoles, respectively; P less than 0.01). In the subendocardium, flow was 49.8 +/- 14.7% lower in the beating condition than during prolonged diastoles (4.23 +/- 1.46 and 8.26 +/- 1.71 ml.min-1.g-1 for beating and asystole, respectively; P less than 0.01). When heart rate was increased stepwise from 60 to 150 beats/min, subendocardial flow fell approximately linearly; flow to the superficial layer was relatively unaffected. In beating hearts, lowering mean left main coronary artery (LMCA) pressure from 80 to 50 mmHg resulted in more systolic reverse flow and a fall in inner-to-outer flow ratio from 0.82 +/- 0.18 to 0.66 +/- 0.34 (P less than 0.05). Because mean LMCA pressure was held constant when the heart was stopped, differences in regional blood flow between beating and diastolic conditions were primarily due to cardiac contraction. Because little or no blood entered the myocardium from the extramural arteries during systole, we conclude that the decrease in subendocardial flow and the increase in subepicardial flow were caused by retrograde pumping of blood from the deep layer to the superficial layer of the left ventricle. Systolic retrograde flow to the subepicardium may help explain this layer's relative protection from ischemia.
Animals↗
Nonuniform blood flow in the canine left ventricle.
In order to investigate the relationship between coronary perfusion pressure and blood flow distribution in the left ventricle (LV), we measured myocardial blood flow in small regions using radioactive microspheres in six anesthetized, open-chest dogs. Mean coronary perfusion pressure (CPP) was controlled with a femoral artery to left main coronary artery shunt which included a pressurized, servo-controlled blood reservoir. In each dog, we measured flow in 192 regions of the LV free wall (mean weight per region = 206 +/- 38 mg) at different perfusion pressures. At CPP = 80 mm Hg, blood flow to individual regions varied fourfold (0.30 to 1.18 ml/min/g; relative dispersion (RD) = 21.8 +/- 2.3%). At CPP = 50 mm Hg, flow varied over sevenfold (0.08 to 0.60 ml/min/g; RD = 42.8 +/- 10%; P less than 0.01 vs 80 mm Hg). This relationship between flow variability and CPP was present within individual LV layers as well between layers and is much higher than the error associated with the microsphere technique. We conclude that blood flow to small regions of the LV is markedly nonuniform. This heterogeneity becomes more profound at lower CPP. These findings suggest that (1) global measurements of coronary flow must be interpreted with caution, and (2) even in hearts with normal coronary arteries some regions of the LV are more susceptible to ischemia than others. In addition, these findings may help explain the patchy nature of myocardial damage that occurs following periods of low coronary pressure or inadequate myocardial protection during cardiopulmonary bypass.
Animals↗
Local blood flow measured by fluorescence excitation of nonradioactive microspheres.
An X-ray fluorescence system with low Compton background and high counting efficiency was developed to measure regional blood flow with nonradioactive microspheres. The performance of the system was tested in vitro by counting mixed aqueous solutions of either Mo, Ag, and I; Nb, Ag, and Ba; or Zr, Mo, Rh, Ag, Sn, I, and Ba, as well as a mixture of Ag and Ba nonradioactive microspheres. Mixtures containing 2-20 ppm of each element were counted for 10 min by the fluorescence system, and the individual elements in mixtures of three to seven nonradioactive elements were measured with high accuracy. The best counting statistics were obtained for Ag. For 10-min counts, the system measures as few as 120 Ag microspheres with 30% standard deviation but measures 800 Ag microspheres per sample with 3.6% standard deviation. We compared regional myocardial blood flows determined simultaneously by fluorescence and radioactive microsphere methods; the latter samples were counted by a 3-in. NaI (Tl) well detector and pulse-height analyzer. The radioactive and nonradioactive measurements showed good correlations.
Animals↗
Nonuniform loss of regional flow reserve during myocardial ischemia in dogs.
To determine whether coronary vasodilator reserve that persists during myocardial ischemia is present in all left ventricular regions, we measured regional blood flow in 192 left ventricular pieces (mean weight, 201 mg) in each of eight dogs by using radioactive microspheres while perfusing the left main coronary artery at 70, 50, 40, and 30 mm Hg. Flows were measured before and during adenosine infusion to determine flow reserve. Perfusion at 40 and 30 mm Hg produced ischemia in all dogs. At 70 mm Hg, 100% of left ventricular regions had significant flow reserve, compared with 92%, 55%, and 8% during perfusion at 50, 40, and 30 mm Hg, respectively. A greater amount of flow reserve and a greater number of regions responded to adenosine in the subepicardium than in the subendocardium at 50, 40, and 30 mm Hg. We conclude that coronary flow reserve persists in only a subset of left ventricular regions during ischemia and that the number of regions with persistent flow reserve decreases with perfusion pressure. These findings may best be explained by a model in which regional ischemia is a maximal coronary vasodilator and persistent pharmacological vasodilator reserve seen when global markers indicate ischemia simply reflects persistent endogenous flow reserve in myocardial regions not yet ischemic.
Adenosine↗
Profound spatial heterogeneity of coronary reserve. Discordance between patterns of resting and maximal myocardial blood flow.
We examined the ability of individual regions of the canine left ventricle to increase blood flow relative to baseline rates of perfusion. Regional coronary flow was measured by injecting radioactive microspheres over 90 seconds in seven anesthetized mongrel dogs. Preliminary experiments demonstrated a correlation between the regional distributions of blood flow during asphyxia and pharmacological vasodilatation with adenosine (mean r = 0.75; 192 regions in each of two dogs), both of which resulted in increased coronary flow. Subsequent experiments, during which coronary perfusion pressure was held constant at 80 mm Hg, examined the pattern of blood flow in 384 regions (mean weight, 106 mg) of the left ventricular free wall during resting flow and during maximal coronary flow effected by intracoronary adenosine infusion. We found that resting and maximal flow patterns were completely uncorrelated to each other in a given dog (mean r = 0.06, p = NS; n = 3 dogs). Furthermore, regional coronary reserve, defined as the ratio of maximal to resting flow, ranged from 1.75 (i.e., resting flow was 57% of maximum) to 21.9 (resting flow was 4.5% of maximum). Thus, coronary reserve is spatially heterogeneous and determined by two distinct perfusion patterns: the resting (control) pattern and the maximal perfusion pattern. Normal hearts, therefore, contain small regions that may be relatively more vulnerable to ischemia. This may explain the patchy nature of infarction with hypoxia and at reduced perfusion pressures as well as the difficulty of using global parameters to predict regional ischemia. Despite the wide dispersion of coronary reserve, we found, by autocorrelation analysis, that reserve in neighboring regions (even when separated by a distance of several tissue samples) was significantly correlated. This also applied to patterns of resting myocardial flow. Thus, both resting coronary blood flow and reserve appear to be locally continuous and may define functional zones of vascular control and vulnerability, respectively.
Adenosine↗
Heterogeneous delivery of cardioplegic solution in the absence of coronary artery disease.
The prevention of intraoperative myocardial damage with cardioplegic solution depends in large measure on the completeness of its delivery. We created a model to study the regional flow distribution of cardioplegic solutions in nondiseased, diastolically arrested, maximally vasodilated canine hearts. Global and regional myocardial flows were measured at different perfusion pressures in hearts perfused either with blood cardioplegic solution (n = 8) or oxygenated crystalloid cardioplegic solution (n = 2). As coronary perfusion decreased, flow in all layers fell significantly (p less than 0.001). This fall was most dramatic in the subendocardium (p less than 0.05). With both types of cardioplegic solutions, the relationship between pressure and flow was nonlinear: At low coronary perfusion pressures, a given change in pressure resulted in a smaller change in flow than at higher perfusion pressures. In addition, we found that in all dogs and at all pressures there was profound variability in the delivery of cardioplegic solution to different small regions of the left ventricular free wall. At a perfusion pressure of 40 mm Hg, the extremes of regional flow differed on average by 203%. This heterogeneity increased significantly with decreasing perfusion pressures. At the lowest perfusion pressure measured (20 mm Hg), the extremes of regional flow differed on average by 365%. These findings emphasize the importance of coronary pressure on the delivery of cardioplegic solution. At low perfusion pressures, not only is mean flow reduced, but a greater number of regions receive limited amounts of cardioplegic solution. These observations may explain the patchy nature of subendocardial damage seen with inadequate myocardial protection.
Animals↗
Quantitating error in blood flow measurements with radioactive microspheres.
Accurate determination of the reproducibility of measurements using the microsphere technique is important in assessing differences in blood flow to different organs or regions within organs, as well as changes in perfusion under various experimental conditions. The sources of error of the technique are briefly reviewed. In addition, we derived a method for combining quantifiable sources of error into a single estimate that was evaluated experimentally by simultaneously injecting eight or nine sets of microspheres (each with a different radionuclide label) into four anesthetized dogs. Each nuclide was used to calculate blood flow in 145-190 myocardial regions. We compared each flow determination (using a single nuclide label) with a weighted mean for the piece (based on the remaining nuclides). The difference was defined as "measured" error. In all, there were a total of 5,975 flow observations. We compared measured error with theoretical estimates based on the Poisson error of radioactive disintegration and microsphere entrapment, nuclide separation error, and reference flow error. We found that combined estimates based on these sources completely accounted for measured error in the relative distribution of microspheres. In addition, our estimates of the error in measuring absolute flows (which were established using microsphere reference samples) slightly, but significantly, underestimated measured error in absolute flow.
Animals↗
Usefulness and limitations of regional cardiac sympathectomy by phenol.
We evaluated the completeness and extent of regional sympathetic denervation of the left ventricle after epicardial painting with phenol in anesthetized dogs. In a region encircled by phenol, the effect of electrical stimulation of efferent sympathetic fibers on myocardial contractility and coronary vascular resistance was completely abolished within 30 min. Denervation extended to untreated regions innervated by sympathetic fibers crossing the phenol line. For at least 4 h after phenol application, intravenous infusion of isoproterenol or coronary arterial infusion of tyramine increased myocardial contractility in the denervated region; norepinephrine content and neurotransmitter uptake were normal, indicating that nerve terminals, postjunctional receptors, and myocardium remained functional. However, after 3-14 days, tissue catecholamine content and transmitter uptake in the encircled area were markedly reduced. The results suggest that careful evaluation is necessary in selecting a fully innervated control region in studies employing regional sympathetic denervation with phenol.
Administration, Topical↗
A historical perspective on the changing methods of management for major trauma of the lower extremity.
The quantity of severe injuries to the extremities challenging the modern, civilian surgeon cannot compare with that produced at Gettysburg or other battles of the Civil War. Nonetheless, the extent and severity of the trauma to the extremity generated on our "civilian battlefields" match and often surpass the wounds confronted by our predecessors. In the Civil War, as it had been for many preceeding years, amputation remained the dominant approach to managing a great variety of injuries to the extremities. However, constant surgical progress, as reflected by a gradual reduction in recourse to amputation, had enabled each succeeding generation of surgeons to surpass and distance themselves from their predecessors. Amputation of the traumatized extremity had always defined and continues to represent the prevalent abilities and limitations of conservative and reconstructive surgical efforts. Operative treatment, for much of its existence, represented a collection of dangerous ablative procedures which were used reluctantly when all other measures were exhausted. Its transformation into a successful reconstructive endeavor evolved primarily in this century. The understanding of bone healing and the functional importance of the knee joint led to a transformation in amputation and to changes in the management of fractures which are still evolving. The next revolution in operative treatment came with the ability to restore blood flow in injured extremities. Finally, the recent introduction of a variety of free flaps enables the reconstitution of extensive soft tissue and bony defects and further lowers the number of obligatory amputations. These innovations enabled the surgeon to reduce his or her recourse to amputation of severely injured extremities. Nonetheless, the significant number of amputations still performed constitute a reminder that there is still work to be done.
Amputation, Surgical↗
Right ventricular thrombus: an unusual manifestation of Behçet's disease.
Behcet's disease is a chronic multisystem illness in which cardiac involvement is a rare manifestation. In this unusual case a young man had symptoms that primarily related to recurrent right ventricular thrombi and pulmonary thromboemboli. Transesophageal echocardiography was useful in documenting the presence of intracardiac thrombus and establishing the diagnosis.
Adult↗
Effective use of heparin-bonded circuits and lower anticoagulation for coronary artery bypass grafting in Jehovah's Witnesses.
Despite many advances in blood conservation techniques, a significant proportion of patients undergoing primary coronary revascularization still require homologous transfusions. Based on a large clinical experience with high-risk patients during coronary artery bypass, a comprehensive strategy to diminish perioperative blood loss was developed by integrating many individual components. An integral component in this strategy is the use of lower heparinization (activated clotting time [ACT] > 280 sec) in conjunction with "tip-to-tip" heparin-bonded cardiopulmonary bypass (CPB) circuits (HBC). This technique was prospectively applied to a group of Jehovah's Witnesses (JW) patients who refuse blood transfusion on religious grounds (n = 9). Outcome was compared to a matched group of patients treated with full heparinization (ACT > 480 sec) used with conventional, nonheparin-bonded CPB circuits (NHBC) performed within the same academic year (n = 455). There were no complications in JW patients who had a significantly lower mediastinal and pleural tube output in the first 24 hours (323 67 mL vs 984 616 mL, p < 0.01). In comparison to JW patients who received no transfusions, 68.1% of patients treated with NHBC were transfused (p 0.0001). In summary, HBC in conjunction with lower anticoagulation was effectively and safely applied to JW patients undergoing coronary artery bypass grafting. This technique should be considered for broader clinical use.
Aged↗
Enhanced blood conservation in primary coronary artery bypass surgery using heparin-bonded circuits with lower anticoagulation.
BACKGROUND: Despite many advances in blood conservation techniques, a significant proportion of patients undergoing primary coronary revascularization still require homologous transfusions. A comprehensive strategy to diminish perioperative blood loss was developed by integrating many individual components to create an improved blood conservation environment and was prospectively applied to 557 patients undergoing primary coronary artery bypass grafting (CABG) procedures performed in our medical center over a 14-month period. METHODS: The first 455 patients were treated with conventional, nonheparinbonded circuits (NHBCs) and full anticoagulation (activated clotting time [ACT] > 480 sec). We wanted to test the hypothesis of whether "tip-to-tip" heparin-bonded circuits (HBCs) used in conjunction with lower anticoagulation (ACT > 280 sec) when added to our current blood conservation environment can further enhance clinical outcomes. We prospectively applied this technique to a consecutive group of patients (n = 102). RESULTS: Compared to patients treated with NHBCs, patients treated with HBCs had a significantly lower mediastinal and pleural chest tube output in the first 24 hours (683 +/- 561 mL vs 984 +/- 616 mL, p < 0.00001) were less likely to be transfused (52% vs 68.1%, p < 0.01) and had a lower exposure to different blood donor units (4.1 +/- 8.4 vs 9.3 +/- 10.3, p < 0.000003). There were no complications directly related to HBCs used in conjunction with lower anticoagulation. Morbidity and mortality rates were similar in both treatment groups. CONCLUSION: In summary, HBCs in conjunction with lower anticoagulation were safely applied in patients undergoing primary CABG with marked improvement in blood conservation, and should be considered for broader clinical use.
Aged↗
Enhanced blood conservation and improved clinical outcome after valve surgery using heparin-bonded cardiopulmonary bypass circuits.
BACKGROUND: Recently, heparin-bonded (HBC) cardiopulmonary bypass circuits (CPB) were formed to be associated with improved outcome after coronary artery bypass grafting. There are very few reports on the efficacy and safety of these circuits in valve surgery. METHODS: A retrospective cohort study of all patient populations undergoing first time valve surgery from 1992 to 1995 in a tertiary teaching hospital. Outcomes of 120 patients undergoing valve surgery using HBC and lower anticoagulation HBC were compared to 232 patients treated with conventional circuits and full heparinization (nonheparin-bonded-circuit [NHBC]). RESULTS: Postoperative 24-hour chest tube drainage (558 +/- 466 mL vs 1054 +/- 911 mL, p < 0.00001), and reoperation for bleeding (2.5% vs 8.2%, p = 0.04) were lower in the HBC group. HBC patients required significantly less transfusions (total donor exposure of 6.9 +/- 13.0 units vs 18.6 +/- 26.2 units, p < 0.00001). Multiple linear regression analysis identified CPB time as a predictor of increased homologous blood transfusions, and the use of HBC, a large body surface area, and elective procedure as predictors of decreased transfusions. Perioperative mortality was similar (HBC 2.5%, NHBC 4.7%, p = 0.24). Overall complications were lower in the HBC group (42% vs 56.2%, p = 0.02). Perioperative myocardial infarction (0.8% vs 1.3%, p = 0.58) and cerebrovascular accident (3.3% vs 3.9%, p = 0.53) were similar. Two (1.7%) HBC patients had valve re-replacement compared to none in the NHBC (p = 0.22). Multiple logistic regression model revealed that age and CPB time were associated with increased complications, and the use of HBC with reduced complications. CONCLUSION: Use of HBCs with lower anticoagulation in valve surgery resulted in a significant reduction of transfusion requirements and improved clinical outcome. Because of a potential for early mechanical valve thrombosis, until further data is available, conventional levels of systemic anticoagulation should be achieved when using HBC in valve surgery.
Aged↗
Clinical outcomes in patients undergoing coronary artery bypass grafting with preferred use of the radial artery.
BACKGROUND: The use of the radial artery (RA) for coronary artery bypass grafting (CABG) is still not widely accepted. The purpose of this study was to evaluate the impact of preferred RA utilization on clinical outcomes. METHODS: Data on 138 consecutive patients undergoing CABG using the RA (in addition to the internal mammary artery) were prospectively collected and compared to 228 patients undergoing CABG without the RA. RESULTS: The mean age was 56 +/- 10 years (range 29 to 79 years). Preoperatively 91% (126/138) were in CCS angina Class III/IV, 45% (66/138) were nonelective, and 14% (20/138) were reoperations. An average of 3.5 +/- 0.9 grafts per patient were performed, of which 2.5 +/- 0.5 (71%) were arterial. The RA was used for single distal vessel in 103 patients, for sequential grafting in 35, and overall for 1.3 distal targets per patient. There were no perioperative deaths, reoperation for bleeding, MI, or CVA. Six patients (4%) had minor RA harvest-related complications. The length of hospital stay was 5.6 +/- 3.1 days. Hospital outcomes were similar to a cohort of patients undergoing CABG without RA. Mean follow-up for 99% (137/138) of patients was 7.1 +/- 4.3 months (range 1 to 18 months). Long-term major complications included one sudden death (0.7%) and three MIs (2.2%). At the time of follow-up, 95% (1311137) were in CCS angina Class I/II. Routine thallium stress test performed in 93 patients showed normal perfusion in 98%. There were no long-term major vascular or neurological deficits related to RA harvest. CONCLUSIONS: The use of RA in patients undergoing CABG is safe and effective. These excellent early clinical outcomes justify liberal use of the RA, although long-term follow-up is required to establish its ultimate role as a preferred conduit.
Adult↗