Pulmonary fat embolism during bipolar hip endoprosthesis

Two patients had fatal fat pulmonary embolism during bipolar hip endoprosthesis. Two women, 71-year-old and 76-year-old, with femoral neck fracture underwent bipolar hip endoprosthesis under combined lumbar epidural/general anesthesia. Soon after the placement of bone cement and a femoral stem with a bipolar endoprosthesis in the femoral shaft, the patients developed circulatory collapse. Immediate cardiopulmonary resuscitation did not restore adequate circulation and the patients died 3.5 hours and 1 hour thereafter, respectively. Pathological examination revealed the presence of fat particles within the entire pulmonary arteries, arterioles and capillaries. Main cause of the present pulmonary fat embolism may be an increase in the intramedullary pressure during cement pressurization and femoral stem placement. Anesthetists have to be aware of occurrence of this serious syndrome during bipolar hip endoprosthesis. For earlier detection of this serious complication we recommend to monitor central venous pressure and pulmonary artery pressure in patients undergoing bipolar hip endoprosthesis.     

Canine lung transplantation after more than twenty-four hours of normothermic preservation

BACKGROUND: Consistent clinical results have not been achieved when lung preservation times exceed 6 hours. The aim of this study was to use an alternative normothermic autoperfusion technique for lung preservation and transplantation. METHODS: In six paired dogs, donor lungs were removed, along with the heart, liver, pancreas, duodenum, and both kidneys, and were preserved for 24 to 33 hours in a normothermic autoperfused multiple organ block. Orthotopic left lung transplantation was performed at the end of the preservation period. RESULTS: Lung function was good during the preservation period. With a gas mixture of 50% O2 + 3% CO2 + 47% N2 delivered to the multiorgan block, arterial oxygen tension ranged from 331 +/- 19 to 383 +/- 8 mm Hg; carbon dioxide tension ranged from 18 +/- 5 to 32 +/- 5 mm Hg; and pH ranged from 7.36 +/- 0.02 to 7.45 +/- 0.08. After transplantation, the dogs were kept anesthetized and ventilated for 24 hours with the same gas mixture. The opposite pulmonary artery was occluded 0 to 6 hours after transplantation. Arterial blood pressures were stable after surgery. Arterial oxygen tension was maintained between 205 +/- 39 and 320 +/- 57 mm Hg, and arterial carbon dioxide tension was maintained between 23 +/- 2 and 34 +/- 2 mm Hg. Lung tissue wet/dry weight ratio was 4.94 +/- 0.17 after preservation; this ratio did not differ from that found in normal controls (4.91 +/- 0.10). CONCLUSIONS: This study shows that the lungs were well preserved for more than 24 hours of preservation when the normothermic multiorgan block preparation was used. The transplanted left lung was able to support the anesthetized dog after the opposite pulmonary artery was occluded.     

Effect of limited and standard reaming on cortical bone blood flow and early strength of union following segmental fracture

OBJECTIVE: To quantitatively determine the extent to which limited and standard intramedullary reaming disrupts cortical circulation and to evaluate the effect on the biomechanical properties of the united fracture. DESIGN: Midshaft tibial osteotomies to create a 2.5-centimeter segment of diaphyseal bone were performed in ten adult dogs. Before insertion of a locked intramedullary nail, the tibia was reamed to either 7.0 millimeters (n = 5) or 9.0 millimeters (n = 5). Blood flow was measured using laser Doppler flowmetry during the nailing procedure and at eleven weeks postnailing. Bending stiffness and load to failure were determined for each healed tibia. RESULTS: Tibial blood flow was reduced for the limited and the standard ream groups by 63 percent (p = 0.002) and 83 percent (p = 0.0008), respectively. After canal reaming, perfusion was reduced to a greater extent in the standard ream group (p = 0.009). At eleven weeks postnailing, tibial perfusion increased to the same levels in both groups (p = 0.43) and returned to base-line values. Bending stiffness and load to failure were reduced after limited reaming (p = 0.002, p = 0.003) and standard reaming (p = 0.01, p = 0.002) were performed. Stiffness and load to failure were reduced to the same extent in both groups (p = 0.12, p = 0.25). CONCLUSIONS: Both limited reaming and standard reaming negatively affect diaphyseal cortical circulation. Limited reaming spares cortical perfusion compared with standard reaming at the time of nail insertion. No long-term advantage for limited reaming was demonstrated. Limited reaming may be advantageous acutely for the stabilization of tibial fractures in which the circulation is already compromised.     

Video-assisted thoracoscopy in the evaluation of penetrating thoracic trauma

We report a case of cardiovascular collapse and death occurring intraoperatively during the prophylactic nailing of a metastatic femur using an unreamed femoral nail. The cause of death, as documented by the autopsy, was a massive fat embolism. The risk of fat embolism while performing intramedullary nailing is well known and has been linked to the process of medullary reaming. Unreamed femoral interlocking nails recently have become available. Although recent reports in the literature have concluded that the risk of fat embolism appears less likely while using unreamed implants, the surgeon should carefully consider the indications for any type of intramedullary fixation, particularly when dealing with unbroken femurs exhibiting impending pathologic fracture, or when preexisting pulmonary disease such as metastasis is present.     

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.     

Does the mode of donor death influence the early outcome of lung transplantation? A review of lung transplantation from donors involved in major trauma

BACKGROUND: Pulmonary dysfunction, often delayed in presentation, is among the sequelae of major trauma. Transplantation of lungs from donors involved in major trauma therefore carries a risk of early graft dysfunction. This study was conducted to assess this risk. METHODS: A retrospective comparison of the outcome from 123 donors (57 donors resulting from major trauma, group T, and 66 donors with nontraumatic origin, group NT) in 125 consecutive technically successful lung or heart-lung transplantations. Variables analyzed included the following: clinical and bacteriologic details of donors and indexes of early graft dysfunction in the recipients. RESULTS: Group T donors were more likely to be younger and male (p < 0.05) and more likely to have had lung ventilation for over 48 hours (p < 0.05) than group NT donors. Microbial contamination of routine donor bronchial lavage (72 of 122, 61%) was no higher in group T (34 of 57, 60%), but, in this group, enteric gram-negative bacilli were more common (30% versus 7%; p < 0.05). Male patients were more likely to receive lungs from group T donors (35 male, 23 female), and female patients were more likely to receive lungs from group NT donors (27 male, 40 female). Mode of donor death did not affect the following indexes of early graft function: length of postoperative ventilation, ratio of arterial oxygen tension to fractional concentration of inspired oxygen at 1 or 24 hours after transplantation, or the incidence of diffuse alveolar damage in lung biopsy specimens at 7 days. Thirty-day mortality (28%) was no higher among recipients of group T lungs, but six recipient deaths were donor-related (donor-transmitted pneumonia in five and donor acquired fat embolism in one case). CONCLUSION: The use of donors involved in major trauma does not increase the risk of early complications after lung transplantation providing their specific characteristics are recognized.     

Intramedullary pressure and bone marrow fat intravasation in unreamed femoral nailing

OBJECTIVE: To investigate whether intramedullary pressure and bone marrow fat embolization are different in unreamed compared with conventional reamed femoral nailing. The null hypothesis is that there is no difference between the two techniques. DESIGN: A prospective consecutive nonrandomized clinical trial. METHODS: Intramedullary pressure was measured in the distal femoral fracture fragment at the supracondylar region. Bone marrow fat intravasation was measured by means of the modified Gurd-test. Monitoring was carried out in 31 unreamed and eight reamed intramedullary femoral nailing procedures. RESULTS: Intramedullary pressure increased in the unreamed group to 82 +/- 11 mm Hg during the insertion of 9-mm and 10-mm nails and in the reamed group to 396 +/- 85 mm Hg during reaming of the medullary cavity. Insertion of nails after reaming led to an increase in intramedullary pressure of 79 +/- 13 mm Hg. A positive correlation between fat intravasation and intramedullary pressure was found in each group (rs = 0.73), resulting in less liberation of bone marrow fat in the unreamed group than in the reamed group. CONCLUSIONS: Intramedullary pressure increased significantly in the reamed more than in the unreamed group. Bone marrow fat intravasation depended on the rise in intramedullary pressure, and occurred less frequently in unreamed than in reamed intramedullary femoral fracture stabilization.     

Subretinal neovascularization developing after prophylactic argon laser photocoagulation of atrophic macular scars

Twenty-eight anemic control dogs were subjected to isolated cerebral hypoxemic (PO2,35+/-5 mm Hg) perfusion for 2 hours. All were found to have functional pulmonary impairment. Two hours later, twenty were sacrificed and found to have the bilateral anatomic complex of the respiratory distress syndrome (RDS). All those not sacrificed expired within 20 hours with progressive respiratory distress and at autopsy had the bilateral anatomic complex. Twenty-three beagles with chronic denervation (autotransplantation) of the left lung also were subjected to the 2 hour isolated cerebral arterial hypoxemic perfusion. Minimal pulmonary functional impairment was measurable in all. Ten of sixteen were long-term survivors. The six that succumbed did not appear to suffer respiratory deaths. These six, as well as seven sacrificed 2 hours after perfusion, had the anatomic complex of RDS in the normally innervated right lungs. However, the denervated left lungs were anatomically normal. These findings are offered as additional evidence that RDS has a centrineurogenic etiology. We postulate the following sequence: "shock" causes cerebral (probably hypothalamic) cellular oxygen deprivation and dysfunction; there is autonomically mediated, increased resistance of the pulmonary venules ("postcapillary sphincters"); this leads to capillary hypertension, congestion, hemorrhage, edema, surfactant inactivation, and atelectasis. Pulmonary denervation blocks this sequence and protects the lung.     

Evaluation and determinants of outcome of tuberculosis treatment

We report a case of fat embolism following self injection of vegetable oil in the penis, to treat an impotence. The patient developed respiratory failure and neurological disorders as confusion. A chest roentgenogram revealed diffuse alveolar infiltrate. Initially, he presented an hemoconcentration, and fat globules in his urine. The outcome was favourable in 72 hours, with oxygen and hydration. The diagnosis of fat embolism was made after neurological improvement: the patient admitted to injection his penis with vegetable oil, in his corpus cavernosum.     

Chronic pulmonary thromboendarterectomy complicated by antithrombin III deficiency and antiphospholipid syndrome

Pulmonary thromboendarterectomy was performed on two patients with chronic pulmonary thromboembolism showing thrombotic tendency. Patient 1 was a 25-year-old male with the disease complicated by congenital antithrombin III deficiency. Patient 2 was a 21-year-old male with the disease complicated by antiphospholipid syndrome. Both patients were admitted to the center upon showing dyspnea. Lung perfusion scintigraphy revealed multiple defects in the right and left lungs. Pulmonary arteriography showed occlusion and stenosis from lobar to segmental arteries. Cardiac catheterization showed marked pulmonary hypertension. Pulmonary angioscopy confirmed the presence of organized thrombi while an intravascular ultrasound revealed a thickening of the pulmonary arterial walls in both lungs. After the insertion of an inferior vena cava filter in each patient, surgery was performed. Following a median sternotomy, a cardiopulmonary bypass was utilized to induce deep hypothermia at a pharyngeal temperature of 16 degrees C, after which a thromboendarterectomy of the bilateral pulmonary arteries was performed under intermittent circulatory arrest. A large amount of organized thrombi was extracted from these arteries. After surgery, both patients showed good postoperative outcome with improved blood flow in both lungs, reduced pulmonary arterial pressure and increased cardiac output.     

Combined fractures of the femoral and tibial shafts in the same limb

This paper reports a study of ipsilateral fractures of the femoral and tibial shafts in 21 patients treated according to a detailed plan including shock treatment, prophylaxis against fat embolism, soft-tissue and fracture treatment. Death due to hypovalaemic shock was eliminated and the incidence of fat emboliism (9-5%) reduced in comparison with an earlier series. The tibial fracture was stabilized by plaster or internal fixation as soon as conditions allowed. In most cases the femoral fracture was treated by medullary mailing. Results have improved compared with earlier series. All fractures healed within 15 months, and functional end results have been excellent in the majority of the surviving patients (89%).     

Leg tissue perfusion in simple tibial shaft fractures treated with unreamed and reamed nailing

BACKGROUND: To compare the effects of unreamed and reamed intramedullary nailing on tibialis posterior, dorsalis pedis, and sum (tibialis posterior plus dorsalis pedis) distal arterial peak pulses. Additionally, leg skin temperature and transcutaneous oxygen tension were measured in patients with low energy, closed tibial shaft fractures. METHODS: The patients were randomized to unreamed and reamed groups, and intramedullary nailing without or with reaming was performed under spinal anesthesia. The measurements were carried out before the operation and on 5 postoperative days. RESULTS: In the unreamed group, the only significant difference between contralateral and nailed legs was in raised leg skin temperature (p = 0.0001). In the reamed group, tibialis posterior distal arterial peak pulses and transcutaneous oxygen tension remained at a significantly lower level and leg skin temperature at a significantly higher level, respectively, in the nailed legs after the operation when compared with contralateral legs (p = 0.0026, p = 0.0001, and p = 0.0001, respectively). There were no statistical differences between preoperative and postoperative values in the measured parameters in both groups. Additionally, there were no intergroup changes in the measured parameters in the injured legs. CONCLUSION: The present study suggests that altered distal arterial pulsations, decreased transcutaneous oxymetry values, and thermal reaction are not due to differences in nailing method but caused by a manifestation of the trauma mechanism of the tibial shaft fracture. The potentially negative effects of reaming to soft tissue perfusion parameters could not be established.     

Lung preservation with low-potassium dextran flush in a primate bilateral transplant model

We used a bilateral lung transplant model to confirm, in primates, the results of lung preservation studies previously obtained in a canine single-lung transplant model. The donor lungs were flushed with low-potassium dextran solution and maintained semiinflated with 100% oxygen at 10 degrees C for a planned ischemic time of 12 hours for the lung implanted first. Of eight experiments performed, results in the 6 operative survivors form the basis of this report. After bilateral lung transplantation, animals were maintained on a ventilator for 6 hours; arterial oxygen tension, pulmonary artery pressure, and pulmonary vascular resistance were determined in the recipients at 2, 4, and 6 hours after transplantation and compared with donor values, which served as controls. Arterial oxygen tension in the recipients did not differ from the controls (p = not significant), whereas the pulmonary artery pressure and pulmonary vascular resistance showed significant elevation (p < 0.05 versus control values). After the 6 hours of assessment, the animals were extubated and 3 survived for 48 to 72 hours with a mean arterial oxygen tension of 69 mm Hg on room air. These results demonstrate excellent lung function after a minimum of 12 hours of preservation in a primate model in which the animal is totally dependent on the function of transplanted lung tissue, and confirm the potential for prolonged clinical lung preservation.     

Expression of endothelin-1 and effects of an endothelin receptor antagonist, TAK-044, at reperfusion after cold preservation in a canine lung transplantation model

BACKGROUND: Rapid increase of pulmonary vascular resistance (PVR) early after reperfusion remains a major issue in clinical lung transplantation. A potent vasoconstrictor peptide, endothelin- plays an important role in various pulmonary pathophysiologic conditions and might induce increased PVR. We investigated the expression and influence of endothelin-1, and the effects of an ETA and ETB nonselective endothelin receptor antagonist, TAK-044, at reperfusion after cold preservation in a canine lung transplantation model. METHODS: Left single lung allotransplantation procedures were performed in three groups of animals. In group I (n=5) lungs were preserved for 12 hours; in group II (n=5) lungs were preserved for 18 hours; and in group III (n=6) lungs were also preserved for 18 hours, and TAK-044 (5 mg/kg) was administered just before reperfusion. All donor lungs were flushed and preserved with low-potassium dextran glucose solution at 4 degrees C. RESULTS: Six hours after reperfusion, arterial oxygen tension (mm Hg, inspired oxygen fraction=1.0) was 512.9+/-34.7 in group I, 152.4+/-46.7 in group II, and 509.6+/-29.0 in group III; PVR index (dyne x sec x cm(-5) x m2) was 1130+/-142 in group I, 1820+/-142 in group II, and 1287+/-191 in group III. Plasma endothelin-1 level was elevated significantly, and endothelin-1-like immunoreactivity was found in a variety of pulmonary vascular tissue and was seen less with immunohistochemical evaluation in group II in bronchial tissue. Conclusions: These results suggest that endothelin-1 is expressed as a result of ischemia-reperfusion injury and may worsen early graft function. TAK-044 is beneficial in protecting the graft from high pulmonary vascular resistance and pulmonary edema during the early posttransplantation stage.     

The John Charnley Award. Prophylaxis of fat and bone marrow embolism in cemented total hip arthroplasty

The efficiency of a new cementing technique developed to prevent the risk of intraoperative pulmonary embolism was assessed. Seventy patients with coxarthrosis entered into a prospective, randomized clinical trial. In the control group of 35 cases the total hip replacement was cemented conventionally. In the second group a proximal drainage placed along the Linea aspera, and a distal drainage placed in the diaphysis, created a vacuum in the medullary cavity of the femur during the insertion of the stem. The operation was performed with the patient under blood gas analysis and hemodynamic and transesophageal echocardiography monitoring. Severe transatrial embolic events were observed during the insertion of the femoral component in 94% of the cases of the control group and in 14% of the cases of the vacuum group; the difference is statistically significant. A significant decrease of arterial partial pressure of O2 (-40.8 mm Hg) and increase of the pulmonary shunt values (+28.3%) occurred 5 minutes after the observation of embolic events in the cases operated on conventionally, but these parameters showed minimal changes in the vacuum group. The rise of intramedullary pressure in the femur is the most decisive pathogenic factor of pulmonary embolism during total hip arthroplasty. The logical prophylactic measure to prevent intravasation of fat and bone marrow is to create sufficient drainage. The cohorted investigation showed the value of the vacuum cementing technique for a substantial reduction of intraoperative embolism and pulmonary impairment.     

Complications in connection with venous port systems: prevention and therapy

OBJECTIVE: To assess the effects of graded intramedullary reaming and nailing on the healing pattern of segmental diaphyseal fractures using male Wistar rats. STUDY DESIGN: In male Wistar rats we produced two standardized, partial osteotomies with an eight-millimeter intermediary fragment in the femoral diaphysis. The osteotomies were subsequently manually broken. In Group A, intramedullary reaming was performed to 1.6 millimeters, and the fracture was stabilized with a 1.6-millimeter steel pin. In Group B, the femoral canal was reamed to 2.0 millimeters, and a hollow steel tube of 2.0 millimeters was installed. The rats were allowed free movement. After four, eight, and twelve weeks, eight rats in each group were sacrificed and callus formation, biomechanical properties, and bone blood flow were evaluated. RESULTS: The callus area was relatively constant with time in Group B, whereas a reduction was observed in Group A at twelve weeks. The biomechanical properties increased throughout the experimental period in both groups, and no significant differences between the groups were detected in bending moment, bending rigidity, or fracture energy. Total bone blood flow was substantially increased at four weeks in both groups and decreased throughout the experimental period. In addition, blood flow of the segmental fractured area was substantially increased after four weeks and decreased gradually thereafter. The increases in blood flow tended to be largest in the moderately reamed group. CONCLUSION: This study indicates that the degree of reaming does not significantly affect the healing pattern measured as restoration of mechanical characteristics.     

Pulmonary inflammatory cell response to sustained endotoxin administration

We have developed a model of human sepsis in sheep. Twenty-four hours after continuous infusion of Escherichia coli endotoxin (lipopolysaccharide) (10 ng.kg-1.min-1) was begun, pulmonary transvascular fluid flux was almost five times the baseline values, cardiac output was nearly doubled, and mean arterial pressure was reduced by approximately 20 mmHg. At this time, the animals were killed and their lungs were fixed by endotracheal installation of 2.5% glutaraldehyde at 25 cmH2O pressure. Morphometry was performed by point counting, and data were expressed as relative volume density. Pulmonary edema and congestion were observed in sheep receiving lipopolysaccharide, whereas sham controls appeared normal. There was an increase in interstitial volume density. There was a significant increase (P < 0.01) in volume density of the pulmonary intravasculature (180%), interstitial macrophages (270%), and mast cells (240%). The volume densities of intravascular and interstitial polymorphonuclear neutrophils also showed a small insignificant increase.     

Reamed femoral nailing in patients with multiple injuries. Adverse effects of tourniquet use

Limb reperfusion after tourniquet ischemia causes pulmonary microvascular injury. Similarly, microembolization, like that associated with reamed femoral nailing, can induce pulmonary microvascular injury. Both processes result in increased pulmonary capillary membrane permeability and edema. However, the association between femoral nailing followed by tourniquet ischemia and clinical lung injury has not been described. The authors reviewed 72 patients with femoral shaft fractures and tibial or ankle fractures requiring internal fixation between 1987 and 1993. All femoral shaft fractures were treated with reamed intramedullary nails. Patients were divided into groups, based on whether the tibial or ankle injury was managed surgically with (Group T, 34 patients) or without (Group NT, 38 patients) a tourniquet. Group T was subdivided based on tourniquet time: T1, less than or equal to 90 minutes; T2, greater than 90 minutes. Groups were matched for injury severity. Group NT had fewer ventilator dependent days and intensive care days than Group T (NT: ventilator dependent days, 2.5 +/- 5.2; intensive care days, 3.9 +/- 6.5; T: 5.1 +/- 6.4; intensive care days, 6.7 +/- 6.6). Ventilator dependent days and intensive care days increased with increasing tourniquet time (T1: ventilator dependent days, 3.2 +/- 3.6; intensive care days, 5.4 +/- 4.6; T2: ventilator dependent days, 7.5 +/- 8.5; intensive care days, 8.5 +/- 8.5), suggesting that in patients with multitrauma, combining reamed femoral nailing with fracture fixation under tourniquet control increases pulmonary morbidity. Further investigation to measure pulmonary injury associated with ischemia reperfusion and intramedullary nailing in patients with multitrauma is warranted.     

Aggregation fo blood platelets and increased hydraulic conductivity of pulmonary exchange vessels

Pulmonary microembolization secondary to platelet aggregation has been suggested to be a pathogenetic component of the shock lung syndrome. In vitro experiments have also shown that platelets can release factors with a permeability-enhancing activity. We studied the effect of collagen-induced platelet aggregation on the hydraulic conductivity of thexchange vessels in isolated, blood-perfused rabbit lungs. The net rate of fluid filtration in each pair of lungs was determined during standardized elevations of left atrial pressure before and after platelet aggregation induced by intraarterial collagen infusions. Such infusions were followed by a significant, but transient increase in the net rate of fluid filtration. These lungs were papaverinized so that collagen infusions caused only minor increases in inflow pressure. Separate experiments indicated that the observed increase in pulmonary arterial pressure could not explain the increase in net filtration rate after collagen infusion. When platelet-poor plasma was used as a perfusate no change in the net rate of fluid filtration was observed after collagen infusion. The conclusion from these experiments is then that intravascular platelet aggregation induced by collagen infusion caused a transient increase in the permeability of the pulmonary exchange vessels.     

Lung function and morphology after bilateral hilar stripping in dogs

Acute changes of lung function and morphology were studied in 3 groups of dogs: after bilateral hilar stripping by ipsilateral approach (group 1), after right-side hilar stripping and left pneumonectomy by left-sided approach only (group 2) and in a control group. All dogs of group 1 showed a syndrome corresponding to functional hilar stripping with absent Hering-Breuer and cough reflex, slow respiration with increased tidal volume and discharge of fluid from the airways. Alveolar ventilation and oxygen tension, dead space/tidal volume ratio and pulmonary shunting did not change. Cardiac output and arterial oxygen tension were decreased. The lungs were heavy and histological examination showed lymphostasis and interstitial edema. The dogs of group 2 did not show significant changes in comparison to the control group.