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Biomedical subjects

I L Kron

Publications and source records attributed to I L Kron.

At least 19 recordsLinked to original sources
PubMed1997

Intraoperative hetastarch infusion impairs hemostasis after cardiac operations.

BACKGROUND: An outbreak of excessive bleeding after cardiac operations occurred at our institution when 5% albumin was in short supply and hetastarch became the preferred intraoperative colloid. As hetastarch may impair coagulation, we investigated the effects of its intraoperative administration on post-cardiac surgical hemostasis. METHODS: Indices of postoperative hemostasis were analyzed in 189 consecutive patients undergoing coronary artery bypass grafting. Three groups were compared: one group (n = 68) received a mean of 796 mL of hetastarch only in the operating room (a few minutes after cessation of cardiopulmonary bypass), another group (n = 59) received a mean of 856 mL postoperatively only, and a third group (n = 62) received no hetastarch. RESULTS: Compared with the other two groups, those patients administered hetastarch intraoperatively exhibited significant reductions in hematocrit and platelet count, a significant prolongation in the prothrombin time, and significant increases in both blood loss and hemostatic drug requirement. Also identified were obvious trends toward a greater transfusion requirement and reexploration rate for bleeding in the latter group. CONCLUSIONS: Hetastarch infusion just after weaning from cardiopulmonary bypass produces a clinically important impairment in post-cardiac surgical hemostasis. Intraoperative use of this agent during heart operations should be avoided until the safe timing of its administration is clarified.

Blood Loss, Surgical↗
PubMed1997

Intravenous phenylephrine preconditioning of cardiac grafts from non-heart-beating donors.

BACKGROUND: Hypoxia and warm ischemia produce severe injury to cardiac grafts harvested from non-heartbeating donors. To potentially improve recovery of such grafts, we studied the effects of intravenous phenylephrine preconditioning. METHODS: Thirty-seven blood-perfused rabbit hearts were studied. Three groups of non-heart-beating donors underwent intravenous treatment with phenylephrine at 12.5 (n = 8), 25 (n = 7), or 50 microg/kg (n = 7) before initiation of apnea. Non-heart-beating controls (n = 8) received saline vehicle. Hypoxic cardiac arrest occurred after 6 to 12 minutes of apnea, followed by 20 minutes of warm in vivo ischemia. A 45-minute period of ex vivo reperfusion ensued. Nonischemic controls (n = 7) were perfused without antecedent hypoxia or ischemia. RESULTS: Phenylephrine 25 microg/kg significantly delayed the onset of hypoxic cardiac arrest compared with saline controls (9.6 +/- 0.5 versus 7.7 +/- 0.4 minutes; p = 0.00001), yet improved recovery of left ventricular developed pressure compared with saline controls (57.1 +/- 5.3 versus 41.0 +/- 3.4 mm Hg; p = 0.04). Phenylephrine 25 microg/kg also yielded a trend toward less myocardial edema than saline vehicle (p = 0.09). CONCLUSIONS: Functional recovery of nonbeating cardiac grafts is improved by preconditioning. We provide evidence that the myocardium can be preconditioned with phenylephrine against hypoxic cardiac arrest.

Analysis of Variance↗
PubMed1997

Low-dose sodium nitroprusside reduces pulmonary reperfusion injury.

BACKGROUND: Reperfusion injury is a significant cause of early allograft dysfunction after lung transplantation. We hypothesized that direct pulmonary arterial infusion of an intravascular nitric oxide donor, sodium nitroprusside (SNP), would ameliorate pulmonary reperfusion injury more effectively than inhaled nitric oxide without causing profound systemic hypotension. METHODS: Using an isolated, ventilated, whole-blood-perfused rabbit lung model, we studied the effects of both inhaled and intravascular nitric oxide during lung reperfusion. Group I (control) lungs (New Zealand White rabbits, 3 to 3.5 kg) were harvested en bloc, flushed with Euro-Collins solution, and then stored inflated for 18 hours at 4 degrees C. Lungs were then reperfused with whole blood and ventilated with 60% oxygen for 30 minutes. Groups II, III, and IV received pulmonary arterial infusions of SNP at 0.2, 1.0, and 5.0 micrograms.kg-1.min-1, respectively, whereas group V was ventilated with 60% oxygen and nitric oxide at 80 ppm during reperfusion. RESULTS: Pulmonary arterial infusions of SNP even at 0.2 microgram.kg-1.min-1 (group II) showed significant improvements in pulmonary artery pressure (31.35 +/- 0.8 versus 40.37 +/- 3.3 mm Hg; p < 0.05) and pulmonary vascular resistance (38,946 +/- 1,269 versus 52,727 +/- 3,421 dynes.s/cm-5; p < 0.05) when compared with control (group I) lungs after 30 minutes of reperfusion. Infusions of SNP at 1.0 microgram.kg-1.min-1 (group III) showed additional significant improvements in dynamic airway compliance (1.98 +/- 0.10 versus 1.46 +/- 0.02 mL/mm Hg; p < 0.05), venous-arterial oxygenation gradient (116.00 +/- 24.4 versus 34.43 +/- 2.5 mm Hg; p < 0.05), and wet-to-dry ratio (6.9 +/- 0.9 versus 9.1 +/- 2.2; p < 0.05) when compared with control (group I) lungs. Lungs that received inhaled nitric oxide at 80 ppm (group V) were significantly more compliant (1.82 +/- 0.13 versus 1.46 +/- 0.02 mL/mm Hg; p < 0.05) than control (group I) lungs. CONCLUSIONS: Pulmonary arterial infusion of low-dose SNP during lung reperfusion significantly improves pulmonary hemodynamics, oxygenation, compliance, and edema formation. These effects were achieved at doses of SNP that did not cause profound systemic hypotension. Direct intravascular infusion of SNP via pulmonary arterial catheters could potentially abate reperfusion injury immediately after allograft implantation.

Animals↗
PubMed1997

Is vertical vein ligation necessary in repair of total anomalous pulmonary venous connection?

BACKGROUND: In the repair of total anomalous venous connection, vertical vein ligation is recommended to eliminate left-to-right shunting. However, the small left heart chambers may not always tolerate the immediate increase in blood flow after combined repair and vein ligation. METHODS: A retrospective review of 23 infants and children undergoing correction of total anomalous pulmonary venous connection was undertaken to determine whether vertical vein ligation is a necessary component of successful surgical repair. In 14 patients this vein was ligated, whereas in 9 it was left patent. Six patients who underwent ligation and 5 who did not had pulmonary venous obstruction before operation. RESULTS: The operative mortality rate was 36% (5 of 14 patients) for the ligated group compared with 0% (0 of 9 patients) for the nonligated group (p = 0.06). All deaths occurred in patients with preoperative obstruction and a low mean left atrial pressure, and four of the deaths were directly attributable to left heart failure. Follow-up echocardiography in patients in whom the vertical vein was not ligated revealed adequate cardiac function and no residual left-to-right flow through the previously patent venous conduit. CONCLUSION: Vertical vein ligation during the repair of total anomalous pulmonary venous connection is not routinely necessary and actually may be undesirable in patients with preoperative obstruction, in whom the left heart chambers are particularly small.

Cardiac Surgical Procedures↗
PubMed1997

Postinjury thromboxane receptor blockade ameliorates acute lung injury.

BACKGROUND: Acute lung injury is associated with pulmonary hypertension, intrapulmonary shunting, and increased microvascular permeability, leading to altered oxygenation capacity. Thromboxane A2 has been found to be a central mediator in the development of septic and oleic acid (OA)-induced acute lung injury. Our previous study demonstrated a beneficial effect of preinjury thromboxane A2 receptor blockade. The current study examines the efficacy of postinjury receptor blockade on oxygenation capacity and pulmonary hemodynamics in an isolated lung model of OA-induced acute lung injury. METHODS: Four groups of rabbit heart-lung preparations were studied for 60 minutes in an ex vivo perfusion-ventilation system. Saline control lungs received saline solution during the first 20 minutes of study. Injury control lungs received an OA-ethanol solution during the first 20 minutes. Two treatment groups were used: T10, in which the thromboxane receptor antagonist, SQ30741, was infused 10 minutes after the initiation of OA infusion; and T30, in which the thromboxane receptor antagonist was infused 30 minutes after OA infusion. RESULTS: Significant differences were found in oxygenation (oxygen tension in T10 = 62.6 +/- 11.7 mm Hg, T30 = 68.2 +/- 21.2 mm Hg; injury control = 40.2 +/- 9.0 mm Hg, saline control = 123.5 +/- 16.01 mm Hg; p < 0.001) and percentile change in pulmonary artery pressure (T10 = 1.1% +/- 19.4% increase, T30 = 11.2% +/- 7.3% increase; injury control = 47.6% +/- 20.5%, saline control = 4.2% +/- 6.81%; p < 0.001). CONCLUSIONS: This study demonstrates that blockade of the thromboxane A2 receptor, even after the initiation of acute lung injury, eliminates pulmonary hypertension and improves oxygenation.

Animals↗
PubMed1997

Use of over-sized mature pulmonary lower lobe grafts results in superior pulmonary function.

BACKGROUND: Mature lobar transplantation will increase the pediatric donor organ pool; however, issues regarding size discrepancy between donor grafts and recipient lungs remain unresolved. We hypothesized that an oversized mature pulmonary lobar allograft implanted into an immature recipient would provide adequate longterm pulmonary function versus a size-matched mature lobar graft or an immature whole lung. METHODS: We investigated our hypothesis in a porcine orthotopic left lung transplant model in which 19 immature animals made up one control and three recipient groups. Group I underwent sham left thoracotomy (control, n = 4). Group II received age- and size-matched immature whole left lung transplant (n = 6). Group III received mature size-matched left upper lobe transplants (n = 4). Group IV received mature over-sized left lower lobe transplants (n = 5). Twelve weeks after implantation, data were collected after the native right lung was excluded. RESULTS: Graft weight was significantly elevated in group IV as compared with the explanted lung (72.4 +/- 6.8 versus 38.3 +/- 4.5 g; p = 0.003). Pulmonary artery pressure and pulmonary vascular resistance were significantly elevated in group III as compared with the over-sized mature lower lobe transplants (51.8 +/- 2.2 versus 40.4 +/- 2.5 mm Hg [p < 0.0001] and 1,605.9 +/- 117.5 versus 857.6 +/- 133.6 dynes.s.cm-5 [p < 0.0005], respectively). A trend toward decreased oxygenation was identified in group II. CONCLUSIONS: Over-sized mature lobar grafts provide improved hemodynamics as compared with size-matched grafts. Mature left lower lobe grafts are superior to size-matched upper lobe grafts in this model, probably as a result of an augmented vascular bed.

Age Factors↗
PubMed1997

Acellular low-potassium dextran preserves pulmonary function after 48 hours of ischemia.

BACKGROUND: We previously have shown that extracellular preservation solutions provide superior pulmonary protection after 18 hours of cold ischemia at 4 degrees C in an isolated, whole-blood-perfused, rabbit lung model. We also reported that the addition of 20% whole blood to a low-potassium dextran solution (BLPD) conferred no discernible advantage over low-potassium dextran (LPD) alone in this same model. Our current study was aimed at documenting the importance of blood in buffering extracellular preservation solutions during 24 to 48 hours of hypothermic ischemia. METHODS: We studied three groups of lungs using an isolated, whole-blood-perfused, ventilated, rabbit lung model. Lungs were flushed with Euro-Collins, LPD, or BLPD solution, and then were reperfused after 24, 36, or 48 hours of hypothermic storage at 4 degrees C. Continuous measurements of pulmonary artery pressure, pulmonary vascular resistance, left atrial pressure, tidal volume, and dynamic airway compliance were obtained. Fresh, non-recirculated venous blood was used to determine single-pass pulmonary venous-to-arterial O2 gradients. RESULTS: The 24-hour Euro-Collins group could not be completed because of immediate reperfusion failure. The 36-hour LPD group oxygenated significantly better than the 36-hour BLPD group (363.3 +/- 65.1 versus 145.3 +/- 40.3 mm Hg, respectively; p = 0.015). The 48-hour LPD group also experienced significant improvements in oxygenation when compared with the 48-hour BLPD group (pulmonary venous-arterial O2 difference of 239.4 +/- 48.4 versus 70.7 +/- 19.5 mm Hg, respectively; p = 0.012). The 48-hour LPD group also displayed significant improvements in pulmonary artery pressure (34.72 +/- 0.96 versus 55.52 +/- 7.37 mm Hg, respectively; p = 0.031) and pulmonary vascular resistance (39,737 +/- 1,291 versus 67,594 +/- 9,467 dynes.s.cm-5, respectively; p = 0.027) when compared with the 48-hour BLPD group. There were no significant differences between the three LPD groups. CONCLUSIONS: Extracellular solutions provide improved pulmonary preservation in an isolated rabbit lung model after 48 hours of cold ischemia. The addition of blood to extracellular preservation solutions diminishes pulmonary function when combined with ischemic periods of 36 to 48 hours.

Animals↗
PubMed1997

Mature pulmonary lobar transplants grow in an immature environment.

OBJECTIVE: Mature lobar transplantation will increase the pediatric donor organ pool, but it remains unknown whether such grafts will grow in a developing recipient and provide adequate long-term support. We hypothesized that a mature pulmonary lobar allograft implanted in an immature recipient would grow. METHODS: We investigated our hypothesis in a porcine orthotopic left lung transplant model using animals matched by the major histocompatibility complex to minimize the effects of chronic rejection. Twenty-three immature animals (< 12 weeks of age and < 10 kg total body weight) received either sham left thoracotomy (SH control, n = 4), left upper lobectomy to study compensatory growth (UL control, n = 4), age-matched immature whole left lung transplants (IWL TXP, n = 6), mature (donor > 1 yr in age and > 40 kg in total body weight) left lower lobe transplants (MLL TXP, n = 5), or mature left upper lobe transplants (MUL TXP, n = 4). Twelve weeks after implantation, functional residual capacity of the left lung was measured and arterial blood gas samples were obtained after the native right lung had been excluded. The graft was excised and weighed, and samples for microscopy and wet/dry ratios were collected. RESULTS: Initial and final graft weights were as follows: IWL TXP group (34.6 +/- 1.5 and 107.8 +/- 5.9 gm, p < 0.0001), MLL TXP group (72.4 +/- 6.8 and 111.4 +/- 8.7, p < 0.001), and MUL TXP group (32.8 +/- 1.3 and 92.8 +/- 7.1 gm, respectively, p < 0.004). No significant differences between groups were demonstrated when functional residual capacity, wet/dry ratios, or oxygenation were compared. Immunohistochemical staining for the nuclear antigen Ki-67 demonstrated dividing pneumocytes. CONCLUSIONS: We conclude that a mature lobar graft implanted into an immature recipient grows by pneumocyte division in this model. Mature lobar transplants can be expected to grow and provide adequate long-term function in developing recipients.

Aging↗
PubMed1997

Minimally invasive coronary artery bypass grafting decreases hospital stay and cost.

OBJECTIVE: The authors performed a retrospective cost analysis for patients undergoing revascularization of their left anterior descending (LAD) coronary artery either by standard coronary artery bypass grafting (CABG), percutaneous transluminal coronary angioplasty (PTCA), or minimally invasive coronary artery bypass grafting (MICABG). SUMMARY BACKGROUND DATA: Minimally invasive CABG has become a safe and effective alternative treatment for single-vessel coronary artery disease. However, the acceptance of this procedure as a routine alternative for the treatment of coronary artery disease will depend on both long-term graft patency rates as well as a competitive market cost. METHODS: The authors conducted a retrospective analysis of three patient groups undergoing LAD coronary revascularization from January 1995 to July 1996. Ten patients were selected randomly from this period after PTCA of an LAD lesion with or without stenting. Nine patients underwent standard CABG on cardiopulmonary bypass with a left internal mammary artery. Nine patients received MICABG via a limited left anterior thoracotomy and left internal mammary artery to LAD grafting without the use of cardiopulmonary bypass. RESULTS: Percutaneous transluminal coronary angioplasty (n = 10) was unsuccessful in two patients. One patient in the MICABG group (n = 9) was converted successfully to conventional CABG because of an intramyocardial LAD and dilated left ventricle. There was no operative morbidity or mortality in any group. Average length of stay postprocedure was decreased significantly for both the MICABG and PTCA groups when compared with that of conventional CABG (n = 9) (2.7 + 0.26, p = 0.009, and 2.6 + 0.54, p = 0.006, vs. 4.8 + 0.46, respectively). Total hospital costs for the MICABG and PTCA groups were significantly less when compared with those of standard CABG ($10,129 + 1104, p = 0.0028, and $9113 + 3,039, p = 0.0001, vs. $17,816 + 1043, respectively). There were no statistically significant differences between the MICABG and PTCA groups. CONCLUSIONS: The final role of minimally invasive CABG is unclear. This procedure is clearly cost effective when compared with that of PTCA and conventional CABG. The long-term patency rates for MICABG will determine its overall efficacy.

Angioplasty, Balloon, Coronary↗
PubMed1996

Surgical aspects of a randomized trial of defibrillator implantation during coronary artery bypass surgery. The CABG Patch Trial.

BACKGROUND: Whether prophylactic insertion of an implantable cardioverter defibrillator (ICD) improves the survival of high-risk patients undergoing coronary artery bypass graft surgery (CABG) is being assessed in the CABG Patch Trial. This report describes the surgical aspects of the study. METHODS AND RESULTS: As of February 28, 1995, 847 patients (1.6% of 54102 screened) were enrolled and eligible for randomization to CABG or CABG plus ICD. Intraoperatively, 56 were eliminated by postenrollment exclusions, 67 were judged too unstable for randomization, and 724 were randomized (80% of the goal of 900). The average preoperative ejection fraction was 0.27 +/- 0.06 (n = 724); left ventricular (LV) end-diastolic pressure averaged 22 +/- 12 mm Hg (n = 548) Cardiopulmonary bypass (CPB) time averaged 108 minutes in control subjects, 126 minutes in the ICD group. After CPB, mechanical support was employed in 23% of patients and inotropic support in 73%; shock occurred in 8% and deep sternal wound infection in 1.3%. The surgical mortality was 6%; median length of stay was 8 days. Compared with randomized patients, patients whom surgeons judged too unstable to randomize were distinguished by statistically significant increases in mechanical support after CPB (51% versus 23%, P < .05) and postoperative shock (19% versus 8%, P < .05). Also, surgical mortality was greater (9% versus 6%) but was not statistically significant. CONCLUSIONS: The initial phases of the CABG Patch Trial have been conducted with acceptable surgical mortality, morbidity, and length of stay. Surgical exclusion of some patients from randomization has been corroborated by data indicating hemodynamic instability. This trial will provide information about the risks and outcome of CABG surgery in patients with impaired LV function.

Aged↗
PubMed1996

Low-potassium solution for lung preservation in the setting of high-flow reperfusion.

BACKGROUND: We previously demonstrated that standard preservation using Euro-Collins solution impairs lung function in the setting of high-flow reperfusion because of potassium-induced vasoconstriction. Preservation strategies for single-lung transplantation are an important factor in patients with pulmonary hypertension. This study investigates the hypothesis that low-potassium preservation solution will improve function of lungs subjected to high-flow reperfusion. METHODS: Twenty-one New Zealand white rabbit lungs were harvested and studied on an isolated, blood-perfused model of lung function after 4 hours of cold ischemia at 4 degrees C. Control lungs were preserved with 50 mL/kg of cold saline solution flush (group I). Experimental lungs were preserved with low-potassium solution (group II) or Euro-Collins solution (group III) at similar temperatures and volumes. RESULTS: The pulmonary arteriovenous oxygen gradient at the end of the 30-minute high-flow reperfusion period was significantly higher in group II compared with group III (121.3 +/- 19.2 mm Hg versus 31.1 +/- 4.2 mm Hg; p < 0.001). The pulmonary vascular resistance was significantly lower in group II than in group III (46.3 +/- 1.8 x 10(3) dynes x s x cm(-5) versus 79.8 +/- 8.4 x 10(3) dynes x s x cm(-5); p < 0.01. The percent decrease in dynamic airway compliance in group III was significantly greater than in group I and II (-51.0% +/- 13.3% versus -10.2% +/- 3.4% and -11.2% +/- 2.8%, respectively; p < 0.001). Similarly, the wet to dry ratio of the lungs in group III was significantly greater than in groups I and II (13.9 +/- 2.3 versus 5.9 +/- 0.2 and 6.0 +/- 0.4, respectively; p < 0.001). CONCLUSIONS: These data demonstrate that a low-potassium preservation solution yields improved lung function after high-flow reperfusion in an ex vivo rabbit lung model. Lung preservation should be aimed at the clinical setting.

Animals↗
PubMed1996

Thromboxane receptor blockade improves oxygenation in an experimental model of acute lung injury.

BACKGROUND: Adult respiratory distress syndrome remains a major cause of morbidity and mortality. We investigated the role of thromboxane receptor antagonism in an experimental model of acute lung injury that mimics adult respiratory distress syndrome. METHODS: Three groups of rabbit heart-lung preparations were studied for 30 minutes in an ex vivo blood perfusion/ventilation system. Saline control (SC) lungs received saline solution during the first 20 minutes of study. Injury control (IC) lungs received an oleic acid-ethanol solution during the first 20 minutes. Thromboxane receptor blockade (TRB) lungs received the same injury as IC lungs, but a thromboxane receptor antagonist (SQ30741) was added to the blood perfusate just prior to study. Blood gases were obtained at 10-minute intervals, and tidal volume, pulmonary artery pressure, and lung weight were continuously recorded. Oxygenation was assessed by measuring the percent change in oxygen tension over the 30-minute study period. Tissue samples were collected from all lungs for histologic evaluation. RESULTS: Significant differences were found between SC and IC lungs as well as TRB and IC lungs when comparing pulmonary artery pressure (SC = 33.1 +/- 2.2 mm Hg, TRB = 35.4 +/- 2.1 mm Hg, IC = 60.4 +/- 11.1 mm Hg; p < 0.02) and percent change in oxygenation (SC = -20.6% +/- 10.3%, TRB = -24.2% +/- 9.5%, IC = -57.1% +/- 6.2%; p < 0.03). None of the other variables demonstrated significant differences. CONCLUSIONS: Thromboxane receptor blockade prevents the pulmonary hypertension and the decline in oxygenation seen in an experimental model of acute lung injury that mimics adult respiratory distress syndrome.

Animals↗
PubMed1996

Non-heart-beating donors: a model of thoracic allograft injury.

4ACKGROUND. Non-heart-beating donors (NHBDs) have been proposed for the critical shortage of donors for cardiac and pulmonary transplantation. We determined the effects of prearrest hypoxia and postarrest warm ischemia on cardiac and pulmonary allografts procured from NHBDs undergoing hypoxic arrest. METHODS. Rabbit hearts and lungs were procured from separate donors and placed on isolated blood perfusion circuits. Controls were excised and perfused without ischemia. Heart from NHBDs underwent either prearrest hypoxic perfusion alone or consecutive periods of prearrest hypoxic perfusion and 20 minutes of postarrest warm ischemia. A third group of hearts underwent 30 minutes of warm, global ischemia alone. Two groups of pulmonary allografts were studied using similar hypoxic perfusion/20-minute ischemia and 30-minute ischemia donors. RESULTS. Prearrest hypoxic perfusion clearly causes significant dysfunction of cardiac allografts from NHBDs compared with nonischemic controls. Prearrest hypoxic perfusion combined with postarrest ischemia results in an additive degree of dysfunction more severe than a similar period of warm ischemia alone. Both groups of experimental lungs displayed function similar to that of nonischemic controls in terms of pulmonary hemodynamics, airway resistance, and oxygenation potential. CONCLUSIONS. We conclude that prearrest hypoxic perfusion significantly contributes to the dysfunction of NHBD cardiac allografts. Pulmonary allografts may be more amenable to procurement of NHBDs.

Animals↗
PubMed1996

Controlled reperfusion of cardiac grafts from non-heart-beating donors.

BACKGROUND: Hearts harvested from non-heart-beating donors sustain severe injury during procurement and implantation, mandating interventions to preserve their function. We tested the hypothesis that limiting oxygen delivery during initial reperfusion of such hearts would reduce free-radical injury. METHODS: Rabbits sustained hypoxic arrest after ventilatory withdrawal, followed by 20 minutes of in vivo ischemia. Hearts were excised and reperfused with blood under conditions of high arterial oxygen tension (PaO2) (approximately 400 mm Hg), low PaO2 (approximately 60 to 70 mm Hg), high pressure (80 mm Hg), and low pressure (40 mm Hg), with or without free-radical scavenger infusion. Non-heart-beating donor groups were defined by the initial reperfusion conditions: high PaO2/ high pressure (n = 8), low PaO2/high pressure (n = 7), high PaO2/low pressure (n = 8), low PaO2/low pressure (n = 7), and high PaO2/high pressure/free-radical scavenger infusion (n = 7). RESULTS: After 45 minutes of reperfusion, low PaO2/ high pressure and high PaO2/low pressure had a significantly higher left ventricular developed pressure (63.6 +/- 5.6 and 63.1 +/- 5.6 mm Hg, respectively) than high PaO2/high pressure (40.9 +/- 4.5 mm Hg; p < 0.0000001 versus both). However, high PaO2/high pressure/free-radical scavenger infusion displayed only a trend toward improved ventricular recovery compared with high PaO2/ high pressure. CONCLUSIONS: Initially reperfusing nonbeating cardiac grafts at low PaO2 or low pressure improves recovery, but may involve mechanisms other than decreased free-radical injury.

Animals↗
PubMed1996

Transatrial approach to posterior postinfarct ventricular septal defects.

Repair of posterior postinfarct ventricular septal defects via the transinfarct left ventriculotomy is technically challenging and can be associated with significant morbidity. A transatrial approach avoids incising through the acutely infarcted myocardium and, in selected cases, offers a safe and reliable repair of these defects.

Cardiac Surgical Procedures↗
PubMed1996

Intratracheal surfactant administration preserves airway compliance during lung reperfusion.

BACKGROUND: Decreased airway compliance after lung transplantation has been observed with severe ischemia-reperfusion injury. Further, it has been shown that the surfactant system is impaired after lung preservation and reperfusion. We hypothesized that surfactant replacement after allograft storage could preserve airway compliance during reperfusion. METHODS: Rabbit lungs were harvested after flush with 50 mL/kg of cold saline solution. Immediate control lungs were studied with an isolated ventilation/perfusion apparatus using venous rabbit blood recirculated at 40 mL/min, room-air ventilation at 20 breaths/min, and constant airway pressure (n = 8). Twenty-four-hour control lungs were preserved at 4 degrees C for 24 hours and then similarly studied (n = 7). Surfactant lungs underwent similar harvest and preservation for 24 hours, but received 1.5 mL/kg of intratracheal surfactant 5 minutes before reperfusion (n = 10). Airway pressure and flow were recorded continuously during 30 minutes of reperfusion. Tidal volume and airway compliance were calculated at 30 minutes. RESULTS: Tidal volume was 33.67 +/- 0.57, 15.75 +/- 5.72, and 29.83 +/- 1.07 mL in the immediate control, 24-hour control, and surfactant groups, respectively (p = 0.004, surfactant versus 24-hour control). Airway compliance was 1.94 +/- 0.27, 0.70 +/- 0.09, and 1.46 +/- 0.10 mL/mm Hg in the immediate control, 24-hour control, and surfactant groups, respectively (p = 0.002, surfactant versus 24-hour control). CONCLUSIONS: We conclude that surfactant administration before reperfusion after 24 hours of cold storage preserves tidal volume and airway compliance in the isolated ventilated/perfused rabbit model of lung reperfusion injury.

Animals↗