Unilateral flail chest is seldom a lethal injury.

BACKGROUND: The chest cage is a common target for traumatic damage. Although relatively rare, it is considered to be a serious condition with significant reported mortalities. As most flail injuries are accompanied by severe extrathoracic injuries, it is often difficult to pinpoint a single injury responsible for the patient's death. AIM: To investigate the factors related to mortality when flail injury is diagnosed. METHODS: Data from the Israel National Trauma Registry between 1998 and 2003 included 11,966 chest injuries (262 flail chest injuries) out of a total of 118,211 trauma hospitalisations. Mortality figures were analysed to determine which factors, singly or in combination, influenced flail chest mortality. RESULTS: Road crashes accounted for most flail injuries (76%). The total mortality was 54 (20.6%) of 262 patients with flail chest injuries. 13 (20.4%) of the deaths occurred soon after admission to the emergency room and 37 (68.5%) within the first 24 h. Mortality in moderate to severe injuries (injury severity score (ISS) 9-24) was 3.6% and that in critical injuries 28.5% (ISS >24). Mortality increased with age: 17% in those aged <45 years, 22.1% in those between 45 and 64 years and 28.8% in those >65 years. Age remained a risk for inpatient death when adjusted for severity. Mortality in isolated unilateral flail injury was not more than 6%. Total mortality for traumatic brain injury (TBI) and flail was 34%. Flail, TBI and other major injuries increased the mortality to 61.1%. CONCLUSIONS: Advanced age is associated with higher mortality. Isolated unilateral bony cage instability infrequently leads to death in patients who make it to the emergency department but rather its combination with additional extrathoracic trauma.

The protective role of neocuproine against cardiac damage in isolated perfused rat hearts.

The effect of neocuproine on cardiac injury was studied using retrogradely perfused isolated rat hearts in two experimental systems. In the first system, where hydrogen peroxide-induced damage was studied, neocuproine at the range of 40-175 microM provided protection at the level of 70-85%, as demonstrated by the reduced loss in the peak systolic pressure (P), in +dP/dt and in -dP/dt. In the second system, where ischemia/reperfusion-induced arrhythmias were studied, neocuproine (42 microM) provided a marked protection against cardiac injury as demonstrated by the lowering of the incidence in irreversible ventricular fibrillation, by decreasing the duration of ventricular fibrillation and by the concomitant increase of the duration of normal sinus rhythm, and by improving the post-ischemic recovery of P, +dP/dt and -dP/dt. Free radicals have already been implicated as causative agents in cardiac injury resulting from either hydrogen peroxide or ischemia followed by reperfusion. Additionally, iron and copper have already been shown to drastically exacerbate the injurious effects of free radicals. Thus, the results reported here with neocuproine, a highly effective chelator for both iron and copper, as well as with adventitious copper and with the combination of neocuproine and copper, are in accord with the mediatory role of transition metals in enhancing the deleterious effects induced by free radicals.

Nicorandil decreases postischemic actin oxidation.

This study examined the hypothesis that preconditioning can decrease postischemic oxidative protein damage. Isolated rat hearts were subjected to 25 min of normothermic global ischemia followed by 45 min of reperfusion. These were compared with hearts pretreated with 20 microM nicorandil or preconditioned with two cycles of ischemia. Changes in the high energy phosphates, ATP and phosphocreatine, were followed using (31)P-NMR spectroscopy. Protein carbonyls were assessed using an immunoblot technique. Postischemic hemodynamic function and high energy phosphates recovered to significantly (p <.05) higher levels in nicorandil-treated and ischemic preconditioned hearts as compared to controls. Postischemic protein carbonyl formation was highest in control reperfused hearts but reduced to intermediate between control and preischemic hearts by ischemic preconditioning and virtually prevented by nicorandil pretreatment, with a prominent band at 43 kDa significantly affected (p <.05). Based on immunoshift and immunoprecipitation studies, this band was identified as a mixture of actin isoforms. These studies support the conclusion that nicorandil diminishes protein oxidative damage in general, and specifically actin oxidation, which in the presence of improved supply of high energy phosphates, leads to enhanced postischemic contractile function.

Naturally produced extracellular matrix is an excellent substrate for canine endothelial cell proliferation and resistance to shear stress on PTFE vascular grafts.

PURPOSE: Successful development of a vascular prosthesis lined with endothelial cells (EC) may depend on the ability of the attached cells to resist shear forces after implantation. The present study was designed to investigate EC detachment from extracellular matrix (ECM) precoated vascular prostheses, caused by shear stress in vitro and to test the performance of these grafts in vivo. METHODS: Bovine aortic endothelial cells were seeded inside untreated polytetrafluoro-ethylene (PTFE) vascular graft (10 x 0.6 cm), PTFE graft precoated with fibronectin (FN), or PTFE precoated with FN and a naturally produced ECM (10(6) cells/graft). Sixteen hours after seeding the medium was replaced and unattached cells counted. The strength of endothelial cell attachment was evaluated by subjecting the grafts to a physiologic shear stress of 15 dynes/cm2 for 1 h. The detached cells were collected and quantitated. PTFE or EC preseeded ECM coated grafts were implanted in the common carotid arteries of dogs. RESULTS: While little or no differences were found in the extent of endothelial cell attachment to the various grafts (79%, 87% and 94% of the cells attached to PTFE, FN precoated PTFE, or FN+ECM precoated PTFE, respectively), the number of cells retained after a shear stress was significantly increased on ECM coated PTFE (20%, 54% and 85% on PTFE, FN coated PTFE, and FN+ECM coated PTFE, respectively, p <0.01). Implantation experiments in dogs revealed a significant increase in EC coverage and a reduced incidence of thrombus formation on ECM coated grafts that were seeded with autologous saphenous vein endothelial cells prior to implantation. CONCLUSION: ECM coating significantly increased the strength of endothelial cell attachment to vascular prostheses subjected to shear stress. The presence of adhesive macromolecules and potent endothelial cell growth promoting factors may render the ECM a promising substrate for vascular prostheses.

Acute effect of thyroid hormone in the rat heart: role of calcium.

Several observations provide some clues as to the possible mode of the regulatory action of thyroid hormone (TH) in the heart, indicating delayed action at the level of the nucleus and acute effects on the plasma membrane. Here we present evidence for a direct and rapid stimulatory effect of TH in the intact normal heart. In the isolated perfused rat heart, 3,5,3'-tri-iodothyronine (T3) produced a positive inotropic effect increasing both the left ventricular peak systolic pressure (P) and +dP/dt values, but had no significant effect on heart rate. This effect of T3 was: (1) very rapid in onset (starting after 15 s) and transient, increasing gradually to reach a maximum (80% above control) at about 20 min, and declining progressively 20 to 30 min later; (2) dose-related and biphasic, occurring at physiological concentrations as low as 1 pM (+dP/dt) and 10 pM (P), reaching a maximum at 1 nM, and decreasing at higher concentrations; and (3) thyroid hormone specific, as shown by the effects of several TH analogs (L-T3 > L-thyroxine (T4) = D-T3 > D-T4; 3,3',5'-tri-iodothyronine (rT3), 3,5,-L-di-iodothyronine and DL-thyronine had no effect). The calcium blockers nifedipine and verapamil, at concentrations of 10(-8) - 10(-5) M given before or after the addition of T3 (10(-9) - 10(-6) M), inhibited the T3-induced increase in cardiac inotropic activity in a time- and dose-related fashion. We suggest that the acute effect of TH in the heart is plasma membrane-mediated and calcium-dependent.

Surgical correction of diffuse supravalvular aortic stenosis involving the branches of the aortic arch.

A case of diffuse supravalvular aortic stenosis including the ascending aorta, the aortic arch, and its branches is presented. The operative procedure employed for correction is presented in detail and discussed. This is the first report of the successful surgical treatment of this type of malformation.

Computer simulation: a diagnostic method in comparative studies of valve prostheses.

Computer simulation was used to compare flow characteristics through Starr-Edwards and Björk-Shiley valves in the mitral and aortic positions. Pressure and velocity determinations were mathematically computed with the use of a model based on the recognition that blood is a non-Newtonian fluid. The results were displayed in two-dimensional graphic form. In both the mitral and aortic positions the Björk-Shiley prosthesis showed a more favorable laminar flow pattern, producing fewer eddies and smaller pressure and velocity gradients through the occluder. Computer simulation is a valuable adjunct in the comparative testing of the hemodynamic properties of artificial heart valves and offers several advantages over physical simulators.

Traumatic rupture of the thoracic aorta during pregnancy. Surgical considerations.

This is a report of successful management of a traumatic rupture of the thoracic aorta in pregnancy. Both mother and daughter are alive and well 24 months after the injury. The various aspects of the surgical and supportive treatment are discussed.

The effect of amino acids on the ischemic heart. Improvement of oxygenated crystalloid cardioplegic solution by an enriched branched chain amino acid formulation.

This study was designed to test the effect of glucose and a formulation enriched with branched chain amino acids as additives to oxygenated crystalloid cardioplegic solution in the ischemic heart. Energy-depleted isolated working rat hearts were subjected to 68 minutes of normothermic global ischemia during which oxygenated cardioplegic solution was used to protect them. The hearts were then reperfused in the nonworking mode for 10 minutes and for a further 30 minutes in the working mode. The hearts were randomly divided into three groups, in which various oxygenated cardioplegic solutions were perfused. Group 1 (control) was subjected to modified St. Thomas' Hospital cardioplegic solution and groups 2 and 3 to the same solution with the addition of glucose (11.1 mmol/L) and glucose (11.1 mmol/L) and branched chain amino acids, respectively. Recovery of aortic flow, coronary flow, cardiac output, aortic pressure, adenosine triphosphate, creatine phosphate, and oxygen consumption was significantly better in group 2 than in group 1. In addition, recovery of aortic flow, coronary flow, cardiac output, aortic pressure, stroke volume, minute work, adenosine triphosphate, and creatine phosphate was found to be significantly enhanced in group 3. Release of adenine catabolites and lactic dehydrogenase from these hearts during postischemic reperfusion was significantly decreased. Thus, during global ischemia in the energy-depleted heart, the presence of glucose and branched chain amino acids in oxygenated crystalloid cardioplegic solution enhanced myocardial protection.

Quadruple valve commissurotomy.

A 12-year-old girl in congestive heart failure was diagnosed to be suffering from severe polyvalvular disease due to a combination of congenital and rheumatic lesions. Cardiac catheterization demonstrated stenotic lesions of all the heart valves. The child underwent quadruple valve commissurotomy and is symptom free and thriving 2 years later.

The influence of cardiopulmonary bypass on the size of human platelets.

Large and small platelets are present in the bloodstream in nearly equal proportions and comprise about 30 per cent of the normal platelet population. The assumption that cardiopulmonary bypass may alter this platelet population distribution was investigated. Platelet volume distribution curves during and after cardiopulmonary bypass were examined in 12 patients undergoing various intracardiac operation by an electronic particle-sizing apparatus based on the Coulter counter. Mean platelet volume (MPV) was 8.6 +/- 0.7 cubic microns prior to cardiopulmonary bypass. Ten minutes after commencement of cardiopulmonary bypass the MPV decreased to 85 per cent of control levels. A further decrease, reaching a plateau at 75 per cent of prebypass MPV, was reached after 50 minutes on bypass. MPV returned to 87 per cent of prebypass levels 2 hours after discontinuation of cardiopulmonary bypass. Since it is known that platelet count is markedly reduced on cardiopulmonary bypass, a simultaneous 25 per cent decrease in MPV can be explained only by a highly selective disappearance of the large platelets from the circulation. As the larger platelets are younger and functionally more potent than the smaller ones, the selective disappearance of large platelets may thus provide an explanation for the observed alteration in platelet adhesiveness caused by cardiopulmonary bypass.

Long-term evaluation of a new selectively biodegradable vascular graft coated with polyethylene oxide-polylactic acid for right ventricular conduit. An experimental study.

Low-porosity woven Dacron grafts have been used extensively as an extracardiac conduit in the surgical treatment of congenital and acquired heart diseases involving total heparinization. Caution is still warranted in their use, however, because of long-term complications, including calcification and development of obstructive fibrous peel. In contrast, high-porosity grafts offer much better tissue anchorage and healing but cannot be used under heparinization. We have developed a compound vascular prosthesis in which a knitted Dacron graft is coated with a polymeric biodegradable sealant. Polyethylene oxide-polylactic acid-segmented copolymers comprised the degradable component of the graft. In vitro studies showed that the coated prosthesis exhibited a highly flexible elastomer-like mechanical response. The prostheses were completely watertight, and significant degradation started after 1 week, with absorption completed after 3 weeks. Seven woven and six knitted polyethylene oxide-polylactic acid-coated Dacron grafts used as extracordiac conduits (16 mm), connecting the right ventricle and the pulmonary artery were implanted in dogs. The dogs were killed after 12 to 18 months, and the results are reported. Scanning electron microscopy examination showed peel detachment and nonhomogenous intimal surface with fenestrations in the woven graft group, but complete healing and incorporation of the pseudointima with homogenous, thin lining of the luminal surface in the polyethylene oxide-polylactic acid-coated group. Histologic studies indicated much superior healing and anchorage of the periprosthetic tissue and the pseudointima in the polyethylene oxide-polylactic acid-coated grafts. The biodegradable polymer was fully degraded and exhibited a complete incorporation of the compound vascular prosthesis. This study indicates the superior healing properties of these selectively biodegradable grafts, which might increase long-term patency and decrease complications of right ventricular conduits.

The effectiveness of University of Wisconsin solution on prolonged myocardial protection as assessed by phosphorus 31-nuclear magnetic resonance spectroscopy and functional recovery.

The effectiveness of the University of Wisconsin solution on extended myocardial preservation was examined in this study using phosphorus 31-nuclear magnetic resonance spectroscopy. Isolated perfused rat hearts were arrested and stored in four preservation solutions: group 1, modified Krebs-Henseleit solution; group 2, modified St. Thomas' Hospital solution; group 3, oxygenated modified St. Thomas' Hospital solution containing 11 mmol/L glucose; and group 4, University of Wisconsin solution. The changes in myocardial high energy phosphate profiles and the intracellular pH values were measured during 12 hours of cold (4 degrees C) global ischemia and 90 minutes of normothermic reperfusion. Following ischemia, the hearts were assessed for hemodynamic recovery and myocardial water content. During ischemia, adenosine triphosphate depletion was observed in all groups; however, after 5 hours of ischemia, the adenosine triphosphate levels were significantly higher in group 3 compared with the other groups (adenosine triphosphate levels at 6 hours in mumol/gm dry weight: group 3, 7.6; group 4, 3.2; group 2, < 1; p < 0.025). The tissue water content at the end of ischemia was lower with the University of Wisconsin solution compared with the modified St. Thomas' Hospital solution or the oxygenated modified St. Thomas' Hospital solution (in ml/gm dry weight: group 4, 3.0; group 2, 4.4; group 3, 3.9; p < 0.05). The adenosine triphosphate repletion during reperfusion was greater with the University of Wisconsin solution compared with the modified St. Thomas' Hospital solution or the oxygenated modified St. Thomas' Hospital solution (12 mumol/gm dry weight in group 4; 8.1 in group 2; 9.0 in group 3; p < 0.05). Similar findings were obtained for the recovery of left ventricular pressure (in percent of preischemic control: group 4, 70%; group 2, 42%; group 3, 52%; p < 0.01) and coronary flow (group 4, 61%; group 2, 49%; group 3, 49%; p < 0.05). These data suggest that preservation with the University of Wisconsin solution affords improved hemodynamic recovery, enhanced adenosine triphosphate repletion, and reduced tissue edema upon reperfusion; however, oxygenated St. Thomas' Hospital solution with glucose is associated with the preservation of higher myocardial adenosine triphosphate levels during prolonged cold global ischemia. In conclusion, these data indicate that the University of Wisconsin solution might improve graft tolerance of ischemia in clinical heart transplantation.

Pericardial meshing: an effective method for prevention of pericardial adhesions and epicardial reaction after cardiac operations.

Cardiac reoperations, particularly for coronary revascularization, are becoming more frequent and carry increased risk of damage to the heart during resternotomy. We experimentally evaluated a pericardial meshing technique to facilitate primary pericardial closure. In 18 mongrel dogs, an 8 by 5 cm pericardial flap was fashioned through a left thoracotomy. A standardized procedure for induction of pericardial adhesions was carried out in all animals. Animals were divided into three groups of six animals each: Group I (control)--the pericardial flap was primarily resutured; Group II--the flap was meshed and then resutured; and Group III--the flap was replaced by a pericardial substitute. Animals were put to death 8 weeks postoperatively and the pericardial space was examined for adhesions and epicardial reaction. The extent of adhesions and epicardial reaction was graded as: 0--none; 1--minimal; 2--moderate; and 3--severe. Both in Group I and Group III severe pericardial adhesions (grade 2-3) and epicardial reactions (grade 2-3) were formed, which obscured the underlying coronary anatomy. In Group II pericardial adhesions and epicardial reactions were none to minimal (grade 0-1) and the underlying coronary anatomy was not obscured. The meshed pericardium was completely regenerated by normal pericardium within several weeks. This study demonstrates that pericardial meshing facilitates primary tension-free pericardial closure. Free drainage of intrapericardial blood is achieved. A complete anatomic layer between heart and sternum is restored. Pericardial meshing is superior to the pericardial substitutes examined, as adhesions and epicardial reactions are significantly reduced, and the coronary anatomy is readily identifiable.

New solution for prolonged myocardial preservation for transplantation.

BACKGROUND: A solution for prolonged cold storage of the heart has been developed. The Jerusalem-Cape Town Solution (JCT) is an "intracellular" type cardioplegic solution and is formulated to (1) minimize hypothermic-induced cell swelling, (2) diminish intracellular acidosis, (3) prevent the expansion of the interstitial space during the reperfusion, (4) protect against oxygen free radical injury during early reperfusion, and (5) provide substrates for regenerating high-energy phosphates. METHODS: With a Langendorff model, rat hearts were subjected to 15 minutes of perfusion with Krebs-Henseleit, 10 minutes of cardioplegic infusion and 20 hours of cold storage (5 degrees to 6 degrees C). Hearts were reperfused for 60 minutes and hemodynamic recovery was assessed. The hearts were assigned to three groups (eight hearts in each), according to the cardioplegic solution used: group 1, JCT; group 2, Bretschneider's HTK cardioplegic solution; and group 3 University of Wisconsin cold storage solution. RESULTS: After 60 minutes of reperfusion, the recovery of the coronary artery flow in group 1 (JCT) was significantly better than in group 2, and slightly better than in group 3 (64% +/- 8.9%, 47.2% +/- 11.6%, 52.5% +/- 19.9%, mean +/- SD, respectively; group 1 versus group 2, p < 0.01). The recovery of the left ventricular developed pressure (LVDP) was significantly better in group 1 compared with group 2 and group 3 (60.2% +/- 14.5%, 41.1% +/- 12.6% and 36.5% +/- 10.1%, respectively; p < 0.01). The recovery of the heart contractility expressed by the product of LVDP and the heart rate (LVDP x heart rate) was significantly higher in group 1 than in group 2 and group 3 (47.5% +/- 3.4%, 23.6% +/- 9.6%, and 28.7% +/- 8.3%, respectively, p < 0.001). In hearts stored for 12 hours in JCT or HTK, the recovery of the heart contractility did not differ significantly (73.4% +/- 12.7% or 70.8% +/- 30.8%, respectively). Modified reperfusion aimed to improve postischemic heart recovery did not bring significant changes in cardiac mechanical function but resulted in an increase in postischemic coronary artery flow recovery in hearts reperfused with amino acid-enriched buffer. CONCLUSIONS: The JCT solution is effective (as well as HTK) in preserving the ischemic hearts for up to 12 hours. It is superior to HTK or University of Wisconsin solution at 20 hours of isolated ischemic storage.

A new method of sternal reclosure.

A new method is described for stabilizing dehiscence or instability of median sternotomy incisions using stainless steel retention sutures. The method has been used successfully in patients who had disruption of the sternum following open-heart surgery and resulted in no complications. It is recommended also as a preventive measure for closure of the sternum in elderly, debilitated patients with a fragile sternum and with prolonged low cardiac output after operation.

The hemodynamic effects of dopamine following cardiopulmonary bypass.

The hemodynamic effects of dopamine were studied in 19 patients following intracardiac operation or myocardial revascularization using extracorporeal circulation. The heart rate, mean blood pressure, central venous pressure, left atrial and pulmonary artery pressures, cardiac output, and urine output were recorded before and at the end of one-hour infusions of dopamine at 5, 10, and 15 mug/kg/min. Infusion of 5 mug/kg/min of dopamine resulted in the highest gain in cardiac output and stroke work without an increase in myocardial oxygen consumption, as evidenced by lack of significant rise in heart rate. In addition, this dosage was not accompanied by an increase in pulmonary or systemic vascular resistance, nor were other untoward effects observed after administration of 5 mug/kg/min of dopamine.

Pericardial meshing: a new technique to facilitate primary tension-free pericardial closure.

A method is described to facilitate pericardial approximation at the conclusion of open-heart surgical procedures. Before sternal closure, the anterior pericardium is meshed by multiple longitudinal incisions until tension-free closure is possible. The technique was developed by animal experimentation and is now being performed in patients. It has proven to be simple, safe, and effective.

New experimental technique to study blood cardioplegia in the isolated, perfused rat heart.

Blood cardioplegia has been extensively studied clinically and in the large animal experimental model. We describe here a modification of the original Langendorff technique to study continuous warm blood cardioplegia in the isolated, perfused rat heart. The excised heart is mounted on the perfusion apparatus and perfused with Krebs-Henseleit buffer. Prearrest hemodynamics are recorded. The shed blood in the mediastinal cavity (8 to 12 mL) is collected, filtered, and reconstituted into cardioplegic solution (hematocrit, 0.20; K+, 15 mmol/L). Hearts are arrested and maintained at 37 degrees C by continuous recirculation of blood cardioplegia for 1 hour. The blood cardioplegia system consists of a Silastic tubing oxygenator, peristaltic pump, and two filters (40 microns pore size). The heart is reperfused with Krebs-Henseleit solution, and postarrest hemodynamics are recorded. Percentage recovery of peak left ventricular pressure, heart rate, and coronary flow were 98.5 +/- 3.1, 102 +/- 4.2, and 98.5 +/- 4.5 (mean +/- standard error of the mean; n = 6), respectively. Myocardial oxygen consumption during arrest was 57 microL.min-1.g-1 dry wt, which is 10% of the myocardial oxygen consumption of a beating heart in in-vivo and ex-vivo models. These results suggest the feasibility of studying blood cardioplegia in the isolated, perfused rat heart model under controlled conditions. Continuous warm blood cardioplegic arrest provided excellent myocardial protection for 1 hour in this model.

Prevention of urethral strictures following coronary artery bypass graft surgery.

A total of 62 patients undergoing coronary artery bypass graft surgery were randomized into three groups using one of three methods for bladder drainage: 12F Foley catheter introduced after anesthesia prior to surgery (21 patients); 12F Foley catheter introduced after termination of cardiopulmonary bypass period (17 patients); or a suprapubic catheter, introduced after termination of the bypass period (24 patients). Later we also studied 39 consecutive patients undergoing coronary artery bypass graft surgery with a 12F Foley catheter introduced after anesthesia to assess the risk of urethral stricture in a larger group of patients. The patients' records were reviewed and a postal questionnaire was sent to all patients six months after surgery. The response rate was 84 percent, with 36 percent having complaints about micturition; of these 79 percent were evaluated by cystourethrography, and 2 cases of urethral stricture were found. The incidence of major postoperative complications was low, with no differences in rate among the various groups. Our results indicate that the use of small caliber Foley catheters is associated with a low incidence of urethral strictures following coronary artery bypass graft surgery; and when indicated, this type of surgery can be performed with other methods of bladder drainage without increased morbidity.