The effects of femoral intramedullary reaming on pulmonary function in a sheep lung model

Timing of femur fracture fixation: effect on outcome in patients with thoracic and head injuries

BACKGROUND

Optimal timing of femur fracture fixation remains controversial. This study examines the association between the timing of femur fracture fixation and outcome in patients with concomitant chest and head injuries.

METHODS

A retrospective review of registry data from a Level I trauma center identified 1362 patients with a femoral shaft fracture over a 12-year period. Patients were categorized into five groups by timing of femur fracture fixation: Group 1, within 24 hours; Group 2, 24 to 48 hours; Group 3, 48 to 120 hours; Group 4, > 120 hours; and Group 5, patients with no operative fixation. Primary outcome measures included morbidity (specifically, pulmonary complications) and mortality. Secondary outcome measures were hospital length of stay, intensive care unit length of stay, and discharge Glasgow Coma Scale score. Subsets of patients were examined including all patients with multiple injuries (Injury Severity Score > 15), chest trauma (Chest Abbreviated Injury Scale score > or = 2), and head trauma (Head Abbreviated Injury Scale score > or = 2).

RESULTS

Acute respiratory distress syndrome, pneumonia, hospital length of stay, and intensive care unit length of stay were lowest in the group fixed within 24 hours, even in patients with concomitant head or chest trauma. Fixation between 2 and 5 days was associated with a significantly increased incidence of acute respiratory distress syndrome, pneumonia, and fat embolization syndrome in patients with concurrent chest trauma (p < 0.0001). In head-injured patients, discharge Glasgow Coma Scale score was highest in the group fixed within 24 hours. Timing of operative fixation did not affect mortality.

CONCLUSION

Our data show that early femur fracture fixation (< 24 hours) is associated with an improved outcome, even in patients with coexistent head and/or chest trauma. Fixation of femur fractures at 2 to 5 days was associated with a significant increase in pulmonary complications, particularly with concomitant head or chest trauma, and length of stay. Chest and head trauma are not contraindications to early fixation with reamed intramedullary nailing.

Influence of controlled reaming on fat intravasation after femoral osteotomy in sheep

This study assessed the influence of driving speed and revolution rate per minute of two reamers on femoral intramedullary pressure increases and fat intravasation. The AO and Howmedica reamers were tested in four groups with different combinations of driving speed and revolution rate per minute in both femurs in a sheep model. The 24 animals were exposed to hemorrhagic shock after midshaft osteotomy and were resuscitated before reaming of both femoral shafts. Controlled reaming was performed at 15 and 50 mm/second driving speed with 150 and 450 revolutions per minute. Fat intravasation and intramedullary pressure were measured by transesophageal echocardiography, Gurd test, and a piezoelectric gauge, respectively. Low driving speed and high revolutions per minute with the smaller cored reamer led to lower intramedullary pressure changes. The same reaming parameters led to greater pulmonary stress during surgery of the second side. Reaming with a smaller cored reamer and modified reaming parameters leads to a lower increase in intramedullary pressure and reduces the amount of fat intravasation. Primary reamed intramedullary nailing should be done after resuscitation at a low driving speed and high revolutions per minute with a smaller cored reamer to minimize the risk of pulmonary dysfunction.

Pulmonary dysfunction in patients with femoral shaft fracture treated with intramedullary nailing

BACKGROUND

This study was undertaken to determine whether alveolar dead space increases during intramedullary nailing of femoral shaft fractures and whether alveolar dead space predicts postoperative pulmonary dysfunction in patients undergoing intramedullary nailing of a femoral shaft fracture.

METHODS

All patients with a femoral shaft fracture were prospectively enrolled in the study unless there was evidence of acute myocardial infarction, shock, or heart failure. Arterial blood gases were measured at three consecutive time-periods after induction of general anesthesia: before intramedullary nailing and ten and thirty minutes after intramedullary nailing. The end-tidal carbon-dioxide level, minute ventilation, positive end-expiratory pressure, and percent of inspired and expired inhalation agent were recorded simultaneously with the blood-gas measurement. Postoperatively, all subjects were monitored for evidence of pulmonary dysfunction, defined as the need for mechanical ventilation or supplemental oxygen (at a fraction of inspired oxygen of >40%) in the presence of clinical signs of a respiratory rate of >20 breaths/min or the use of accessory muscles of respiration.

RESULTS

Seventy-four patients with a total of eighty femoral shaft fractures completed the study. Fifty fractures (62.5%) underwent nailing after reaming, and thirty fractures (37.5%) underwent nailing with minimal or no reaming. The mean alveolar dead-space measurements before canal opening and at ten and thirty minutes after canal opening were 14.5%, 15.8%, and 15.2% in the total series of seventy-four patients (general linear model, p = 0.2) and 20.5%, 22.7%, and 24.2% in the twenty patients with postoperative pulmonary dysfunction (general linear model, p = 0.05). Of the twenty-one patients with an alveolar dead-space measurement of >20% thirty minutes after nailing, sixteen had postoperative pulmonary dysfunction. According to univariate and multivariate analysis, the alveolar dead-space measurement was strongly associated with postoperative pulmonary dysfunction.

CONCLUSIONS

According to our data, intramedullary nailing of femoral shaft fractures did not significantly increase alveolar dead space, and the amount of alveolar dead space can predict which patients will have pulmonary dysfunction postoperatively.

Fat embolism

Fat embolism syndrome is a collection of respiratory, haematological, neurological and cutaneous symptoms and signs associated with trauma and other disparate surgical and medical conditions. The incidence of the clinical syndrome is low (< 1% in retrospective reviews) whilst the embolisation of marrow fat appears to be an almost inevitable consequence of long bone fractures. There is debate over the pathogenesis of fat embolism syndrome and it seems a variety of factors interact to produce a spectrum of end organ damage. Many therapeutic interventions and prophylactic strategies have been tried with varying success. Current treatments are supportive and the condition is usually associated with a good outcome. The literature on fat embolism syndrome is extensive and this review aims to discuss the incidence, aetiology, pathophysiology, diagnosis and treatment of fat embolism.

The incidence of acute cardiorespiratory and vascular dysfunction following intramedullary nail fixation of femoral metastasis

Intramedullary nail fixation is a common treatment for metastatic tumors of the femur with overt or impending femoral fracture. This procedure sometimes causes severe cardiorespiratory and vascular dysfunction. The clinical relevance of this is not dear. We reviewed 45 operations in 43 patients, where intramedullary nail fixation was used to treat metastatic femoral fractures and impending fractures. We studied the incidence of intraoperative oxygen desaturation and hypotension associated with intramedullary manipulation as markers of cardiorespiratory and vascular dysfunction. Acute oxygen desaturation and hypotension occurred in 11 of our 45 patients. Of these, 3 died, 2 required intensive care postoperatively and 6 made uneventful recoveries. We hope to highlight a serious complication in this patient group.

Intramedullary nailing of the femur: reamed versus nonreamed

All intramedullary nailing creates some loss of endosteal blood supply and an increase in intramedullary pressure, resulting in marrow embolization. In laboratory studies, both reamed and nonreamed intramedullary nailing have led to alteration in selected pulmonary variables. This effect, although transient, appeared more pronounced with reamed techniques than with nonreamed techniques. Concern about the systemic pulmonary effects of reamed intramedullary nailing has led to an increase in the use of nonreamed nailing. The authors of most clinical studies have reported that reamed intramedullary nailing has not been associated with a concomitant increase in pulmonary complications in multiply injured patients, although this point is still controversial. Femoral shaft fractures treated with nonreamed nailing have been shown to have slightly higher rates of delayed union and nonunion compared with those treated with reamed nails. Reamed interlocking intramedullary fixation remains the treatment of choice for femoral shaft fractures in adults. Further study is required to determine whether an identifiable subgroup of trauma patients is adversely affected by intramedullary reaming, which would suggest the need for alternative fixation techniques.

Pathophysiological effect of fat embolism in a canine model of pulmonary contusion

BACKGROUND

The objective of this study was to determine the individual and combined effects of pulmonary contusion and fat embolism on the hemodynamics and pulmonary pathophysiology in a canine model of acute traumatic pulmonary injury.

METHODS

After a thoracotomy, twenty-one skeletally mature dogs were randomly assigned to one of three groups. Unilateral pulmonary contusion alone was produced in Group 1 (seven dogs); pulmonary contusion and fat embolism, in Group 2 (seven dogs); and fat embolism alone, in Group 3 (seven dogs). Pulmonary contusion was produced by standardized compression of the left lung with a piezoelectric force transducer. Fat embolism was produced by femoral and tibial reaming followed by pressurization of the intramedullary canals. Cardiac output, systolic blood pressure, peak airway pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, partial pressure of arterial oxygen, and partial pressure of carbon dioxide were monitored for all groups. From these data, several outcome parameters were calculated: total thoracic compliance, alveolar-arterial oxygen gradient, and ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration. All of the dogs were killed after eight hours, and tissue samples were obtained from the brain, kidneys, and lungs for histological analysis. Lung samples were assigned scores for pulmonary edema (the presence of fluid in the alveoli) and inflammation (the presence of neutrophils or hyaline membranes, or both). The percentage of the total area occupied by fat was determined.

RESULTS

Pulmonary contusion alone caused a significant increase in the alveolar-arterial oxygen gradient but only after seven hours (p = 0.034). Fat embolism alone caused a significant transient decrease in systolic blood pressure (p = 0.001) and a significant transient increase in pulmonary arterial pressure (p = 0.01) and pulmonary capillary wedge pressure (p = 0.015). Fat embolism alone also caused a significant sustained decrease in the ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration (p = 0.0001) and a significant increase in the alveolar-arterial oxygen gradient (p = 0.0001). The combination of pulmonary contusion and fat embolism caused a significant transient increase in pulmonary capillary wedge pressure (p = 0.0013) as well as a significant sustained decrease in partial pressure of arterial oxygen (p = 0.0001) and a significant decrease in systolic blood pressure (p = 0.001) that lasted for an hour. Pulmonary contusion followed by fat embolism caused a significant increase in peak airway pressure (p = 0.015), alveolar-arterial oxygen gradient (p = 0.0001), and pulmonary arterial pressure (p = 0.01), and these effects persisted for five hours. Total thoracic compliance was decreased 6.4 percent by pulmonary contusion alone, 4.6 percent by fat embolism alone, and 23.5 percent by pulmonary contusion followed by fat embolism. The ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration was decreased 23.7 percent by pulmonary contusion alone, 52.3 percent by fat embolism alone, and 65.8 percent by pulmonary contusion followed by fat embolism. The mean pulmonary edema score was significantly higher with the combined injury than with either injury alone (p = 0.0001). None of the samples from the lungs demonstrated inflammation. Fat embolism combined with pulmonary contusion resulted in a significantly greater mean percentage of the area occupied by fat in the noncontused right lung than in the contused left lung (p = 0.001); however, no significant difference between the right and left lungs could be detected with fat embolism alone. The mean percentage of the glomerular and cerebral areas occupied by fat was greater with fat embolism combined with pulmonary contusion than with fat embolism alone (p = 0.0001 and p = 0.01, respectively). (ABSTRACT TRUNCATED)

Prostanoids: early mediators in the secondary injury that develops after unilateral pulmonary contusion

BACKGROUND

We have previously shown a sequence of events after unilateral pulmonary contusion that suggests the release of blood-borne prostanoid mediators and that culminates in refractory bilateral pulmonary failure.

PURPOSE

To determine the role of platelet-derived thromboxane and endothelial-derived prostacyclin in the primary and secondary injury after unilateral blunt chest trauma, and to determine whether pretreatment with the cyclooxygenase inhibitor indomethacin alters the progression of secondary injury.

METHODS

Anesthetized, ventilated (FIO2 = 0.50) pigs received a unilateral, blunt injury to the right thorax (n = 20) or sham injury (n = 5) and were monitored for 24 hours. Either indomethacin (5 mg/kg i.v.; n = 10) or its saline vehicle (n = 10) were administered 15 minutes before injury. Serial bronchoalveolar lavages of each lung were analyzed for protein and neutrophil (polymorphonuclear neutrophil (PMN)) content.

RESULTS

Contusion caused profound hypoxemia; PaO2 partially recovered within 1 hour of injury to 50% of baseline. Thereafter, worsening hypoxemia required positive end-expiratory pressure. With indomethacin compared with vehicle, PaO2 was higher at any given level of positive end-expiratory pressure (p < 0.05). There was an early increase in serial bronchoalveolar lavage protein on the injured side (peak at 2 hours), with a delayed pulmonary capillary leak on the contralateral side (peak at 6 hours), which correlated with increasing PMN infiltration; this was reduced by 40 to 60% with indomethacin (p < 0.05). Thromboxane peaked within 1 hour after contusion at 800% baseline, then fell off rapidly. This peak preceded the maximal increase in permeability and was completely blocked by indomethacin. Prostacyclin slowly rose to 300% baseline by 3 hours and remained elevated; this change was blocked by indomethacin for 18 hours.

CONCLUSIONS

Contusion of the right thorax induced a delayed pulmonary capillary leak in the left lung, which reflects a progressive secondary inflammatory response. Elevations in thromboxane and prostacyclin preceded progressive bilateral PMN infiltration. Indomethacin blocked thromboxane and prostacyclin and attenuated, but did not prevent, the progression to pulmonary failure. Overall, these data suggest that prostanoids are released soon after unilateral contusion and initiate an inflammatory response in both lungs that is sustained by PMN infiltration.

Pulmonary gas exchange during intramedullary fixation of femoral shaft fractures

BACKGROUND

This study was undertaken to determine if the alveolar dead space fraction (Vd/Vt) or the alveolar-arterial oxygen gradient (A-a DO2) increased during intramedullary fixation of femoral shaft fractures.

METHODS

Fifty hemodynamically stable patients with femur fractures were prospectively enrolled. Three serial measurements of Vd/Vt and A-a DO2 were obtained immediately before femoral nailing (Pre), 30 minutes after nailing (+30), and 120 minutes after nailing (+120). Vd/Vt was determined by simultaneously measuring PaCO2 and the steady-state end-tidal CO2 (PetCO2), where Vd/Vt = (1 - PetCO2/PaCO2).

RESULTS

Vd/Vt before nailing was 0.09 +/- 0.09 (mean +/- SD); at +30 and +120, Vd/Vt was 0.10 +/- 0.06 and 0.08 +/- 0.07, respectively (p > 0.2; paired t test, both time points). A-a DO2 before nailing was 84 +/- 85 mm Hg, and it did not change significantly at +30 (89 +/- 69 mm Hg; p = 0.51 vs. Pre; paired t-test) or at +120 (51 +/- 45 mm Hg). No difference in data was found with analysis by fracture classification or number of reamer passes. Vd/Vt and A-a DO2, however, were both significantly increased in patients with lung contusion (n = 6) before nailing, but neither measurement increased after nailing. One patient developed fat embolism (Vd/Vt of 0.35 at Pre and 0.31 at +120), and another patient experienced postoperative pulmonary thromboembolism (Vd/Vt increased from 0.06 at Pre to 0.17 at +120).

CONCLUSION

The process of femoral nailing does not cause enough pulmonary embolization to alter pulmonary gas exchange as measured by Vd/Vt and A-a DO2. If Vd/Vt is increased preoperatively, the likelihood of subsequent pulmonary dysfunction secondary to either preoperative lung injury or fat embolism is increased.

Approach to the polytraumatized patient with musculoskeletal injuries

The management of the multiply injured patient is a challenge for even experienced clinicians. Because many community hospitals lack a dedicated trauma team, it is often the orthopaedic surgeon who will direct treatment. Therefore, the orthopaedic surgeon must have an understanding of established guidelines for the evaluation, resuscitation, and care of the severely injured patient. Initial evaluation encompasses assessment and intervention for airway, breathing, circulation, disability (neurologic injury), and environmental and exposure considerations. Resuscitation requires not only administration of fluids, blood, and blood products but also emergent management of pelvic trauma and stabilization of long-bone fractures. Judicious early use of anterior pelvic external fixation can be lifesaving in many cases. The secondary survey, which is often neglected, must incorporate a thorough physical evaluation. Although the method of fracture stabilization is still controversial, most clinicians agree that early fixation offers many benefits, including early mobilization, improved pulmonary toilet, decreased cardiovascular risk, and improved psychological well-being. Without an understanding of the complexities of the multiply injured patient, delays in the diagnosis and treatment of a patient's injuries are likely to adversely affect outcome.

Effect of femoral fracture and intramedullary fixation on lung capillary leak

BACKGROUND

Pulmonary injury is an important complication in the trauma patient with long-bone fractures. The purpose of this study was to determine the effect of femoral fracture or fracture and intramedullary fixation on lung capillary leak. The contribution of leukocytes to lung injury in this model was also determined.

METHODS

The pulmonary capillary filtration coefficient was determined in lungs of rats after femur fracture or fracture and reamed or unreamed intramedullary fixation. Pulmonary arterial vascular resistance and lung neutrophil content were also determined.

RESULTS

Fracture alone did not cause lung injury, whereas fracture and intramedullary fixation elicited lung capillary leak. Fracture alone and intramedullary fixation increased pulmonary vascular resistance, whereas unreamed intramedullary fixation caused lung leukosequestration.

CONCLUSION

Femoral fracture alone does not cause an increase in pulmonary microvascular permeability. Femoral fracture and intramedullary fixation causes lung capillary leak, which is not increased by reaming the femoral canal.

Intramedullary pressure and bone marrow fat extravasation in reamed and unreamed femoral nailing

This study was designed to investigate whether intramedullary pressure and embolization of bone marrow fat are different in unreamed compared with conventional reamed femoral nailing in vivo. In a baboon model, the femoral shaft was stabilized with interlocking nailing after a midshaft osteotomy. Intramedullary pressure was measured in the distal femoral shaft fragment at the supracondylar region. Extravasation of bone marrow fat was determined by the modified Gurd test (range: 0-5) with blood samples from the vena cava inferior. Data were monitored in eight unreamed and eight reamed intramedullary femoral nailing procedures. Intramedullary pressure increased in the unreamed group to 76 +/- 25 mm Hg (10.1 +/- 3.3 kPa) during insertion of 7-mm nails and in the reamed group to 879 +/- 44 mm Hg (117.2 +/- 5.9 kPa) during reaming of the medullary cavity. Insertion of 9-mm nails after the medullary cavity had been reamed to 10 mm produced an intramedullary pressure of 254 +/- 94 mm Hg (33.9 +/- 12.5 kPa) (p < 0.05). Fat extravasation in the unreamed group was recorded with a score of 2.9 +/- 0.4 for the Gurd test during nailing with 7-mm nails, whereas in the reamed group significantly more fat extravasation was noticed during the reaming procedures, with a score of 4.6 +/- 0.1. Liberation of fat during insertion of 9-mm nails after reaming was recorded with a score of 3.5 +/- 0.4. In both groups, a positive correlation of fat extravasation with the rise in intramedullary pressure was found (reamed group: r(s) = 0.868; unreamed group: r(s) = 0.698), resulting in significantly less liberation of bone marrow fat in the unreamed stabilized group than in the reamed control group (p < 0.05). The data indicate that fat embolization during nailing procedures after femoral osteotomy increases with increasing intramedullary pressure and occurs in a lesser degree in unreamed than in reamed intramedullary femoral shaft stabilization.

In vivo femoral intramedullary pressure during uncemented hip arthroplasty

There is evidence in several animal and human studies that high intramedullary pressure in the femur is of causal significance for bone marrow release into the circulation, causing pulmonary fatty marrow embolization. A previous clinical study provided evidence that in uncemented hip arthroplasty, high intramedullary pressure and subsequent fat embolism with cardiorespiratory deterioration can occur. In this prospective clinical trial, the effect of five surgical techniques on the femoral intramedullary pressure was recorded intraoperatively in 36 patients during uncemented press fit hip arthroplasty. In Group A, the conventional surgical technique (slide hammer and femoral rasps) showed intramedullary hypertension during opening of the femoral canal, femur preparation, and prosthesis insertion. In Group B, a mechanical high frequency vibration rasp was used, instead of the slide hammer, and provided reduction of the intramedullary pressure peaks during opening of the femoral canal but could not prevent intramedullary hypertension during rasping and prosthesis insertion. In Group C, a modified surgical technique to prevent high intramedullary pressure reduced pressure peaks during opening of the femoral canal and resulted in a significant reduction of intramedullary pressure during femur preparation and prosthesis insertion compared with the conventional surgical technique used with Group A. In Group D the results of the modified surgical technique could be improved additionally by using the high frequency vibration rasp, instead of the slide hammer. In Group E conventional surgical technique in combination with a distal venting hole has not proven to be efficient in uncemented hip arthroplasty. Based on the results of this in vivo study, the proposed modified surgical technique in cementless hip arthroplasty can be recommended to avoid high intramedullary pressure peaks, which should minimize the risk of significant bone marrow release into the circulation and the risk for cardiorespiratory deterioration caused by fat embolism.

Coagulatory response after femoral instrumentation after severe trauma in sheep

OBJECTIVE

Pulmonary complications after intramedullary femoral nailing have been attributed to bone marrow fat embolization and a variety of cascade effects. We investigated whether the coagulatory response after intramedullary femoral nailing in merino sheep is altered after severe trauma.

METHODS

Adult merino sheep were submitted to hemorrhagic shock (2 hours, 50 mm Hg) and unilateral lung contusion. After recovery (day 3 of the study), reamed femoral intramedullary nailing (RFN), unreamed femoral intramedullary nailing (UFN), or plate osteosynthesis of the femur (P) was performed. Pulmonary artery pressure, central venous levels of factor V, protein C, antithrombin III, and fibrinogen, were determined. At 1 and 3 days before and after femur instrumentation, pulmonary capillary permeability was assessed on the basis of the comparative albumin content in bronchoalveolar lavage fluid.

RESULTS

Group RFN, n=8; group UFN, n=7; group P, n=6. A significant (p < 0.05) postoperative increase in the relative albumin content in terms of the BAL/plasma albumin ratio was measured in group RFN (day 3 preoperatively: 0.38+/-0.05 day 3 postoperatively: 0.53+/-0.06, p < 0.05 (RFN vs. P), which contrasted with group UFN (day 3 preoperatively: 0.44+/-0.09, day 3 postoperatively: 0.46+/-0.09, no significant difference). This evidence of increased pulmonary permeability occurred in association with evidence of increased activation of coagulation factors (data presented as percentage of day 3 preoperative baseline values). The data for fibrinogen (15 min postoperatively) is as follows: group RFN, 74+/-9% (p < 0.05 vs. P); group UFN, 83+/-8% (not significant); group P, 98+/-6%. The data for antithrombin III (15 min. postoperatively) is as follows: group RFN, 72+/-6% (p < 0.05 vs. P); group UFN, 79+/-8% (not significant); group P, 92+/-8% (not significant).

CONCLUSION

After severe trauma, an increase of pulmonary permeability after reamed femoral nailing was associated with increased consumption of coagulation factors. After unreamed nailing, a similar trend was apparent, but this was not found to be statistically significant. These data provide support for the theory that after severe trauma, unreamed femoral nailing reduces but does not abolish pulmonary sequelae when compared with reamed femoral nailing.

Adult respiratory distress syndrome, pneumonia, and mortality following thoracic injury and a femoral fracture treated either with intramedullary nailing with reaming or with a plate. A comparative study

Multiply injured patients (an Injury Severity Score of 17 points or more) who were admitted to one of two level-I regional trauma centers between 1983 and 1994 because of a fracture of the femoral shaft with a thoracic injury (an Abbreviated Injury Scale score of 2 points or more) or without a thoracic injury were studied retrospectively. The patient populations and the protocols for the treatment of trauma were similar at the two centers; however, the centers differed with regard to the technique that was used for acute stabilization of the fracture of the femoral shaft. At Center I intramedullary nailing with reaming was used in 217 (95 per cent) of the 229 patients, whereas at Center II a plate was used in 206 (92 per cent) of the 224 patients. This difference was used to investigate the effect of acute femoral reaming on the occurrence of adult respiratory distress syndrome in multiply injured patients who had a chest injury. Three groups of patients were evaluated: those who had both a fracture of the femur and a thoracic injury, those who had a fracture of the femur but no thoracic injury, and those who had a thoracic injury without a fracture of the femur or the tibia. The third group was studied at each center to determine if there was a difference between the institutions with regard to the rate of adult respiratory distress syndrome. Patients who had diabetes, chronic obstructive pulmonary disease, asthma, hepatic or renal failure, or an immunosuppressive condition were excluded from the study. The records were abstracted to determine the Injury Severity Score, Abbreviated Injury Scale score, and Glasgow Coma Score for each patient. Requirements for fluid resuscitation were calculated for the first twenty-four hours; these included the number of units of packed red blood cells, fresh-frozen plasma, and platelets that were transfused and the volume of crystalloid that was used. The duration of intubation, the duration of hospitalization, and the occurence of adverse outcomes (death, multiple organ failure, adult respiratory distress syndrome, pneumonia, and pulmonary embolism) were determined for each patient. The groups of patients were analyzed as a whole and then were stratified into subgroups (according to whether or not they had a thoracic injury and whether the Injury Severity Score was less than 30 points or 30 points or more) to determine if the type of fixation of the femoral fracture affected the rate of adult respiratory distress syndrome or mortality. Logistic regression models were used to analyze the data. The over-all occurrence of adult respiratory distress syndrome in the 453 patients who had a femoral fracture was only 2 per cent (ten patients). The rates of adult respiratory distress syndrome for the patients who had a thoracic injury but no femoral fracture (eight [6 per cent] of 129 patients at Center I, compared with ten [8 per cent] of 125 patients at Center II) did not differ between centers, suggesting that the institutions were comparable in their treatment of multiply injured patients. The occurrence of adult respiratory distress syndrome in the patients who had a femoral fracture without a thoracic injury did not differ substantially according to whether the fracture had been treated with a nail (118 patients) or a plate (114 patients). Likewise, the frequency of adult respiratory distress syndrome, pneumonia, pulmonary embolism, failure of multiple organs, or death for the patients who had a femoral fracture and a thoracic injury was similar regardless of whether nailing with reaming (117 patients) or a plate (104 patients) had been used. The use of intramedullary nailing with reaming for acute stabilization of fractures of the femur in multiply injured patients who have a thoracic injury without a major comorbid disease does not appear to increase the occurrence of adult respiratory distress syndrome, pulmonary embolism, failure of multiple organs, pneumonia, or death.