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Occult Hypoperfusion Is Associated with Increased Morbidity in Patients Undergoing Early Femur Fracture Fixation

Crowl, Adam C. MD; Young, Jeffrey S. MD; Kahler, David M. MD; Claridge, Jeffrey A. MD; Chrzanowski, David S. BS; Pomphrey, Michelle RN

Journal of Trauma-Injury Infection & Critical Care: February 2000 - Volume 48 - Issue 2 - pp 260-267
Article Titles

Background: The presence of persistent occult hypoperfusion (OH) is associated with higher morbidity and mortality rates after trauma. Early femur fracture fixation in trauma patients with multiple injuries is associated with decreased morbidity and mortality. Association of OH and incidence of postoperative complications after intramedullary (IM) fixation in patients with femur fractures was investigated.

Methods: A retrospective study design was used. All patients with femur fractures admitted to the trauma service of a Level I trauma center between January 1, 1995, and August 1, 1998, who were older than 18 years of age and who had IM fracture fixation within 24 hours of admission and serum lactate determinations on admission and at proscribed intervals, were included in the study. Patients with lactic acid levels ≥ 2.5 mmol/L were determined to have OH. No patients had clinical signs of shock (hypotension, tachycardia, decreased urine output) on transfer to the operating room. Complete resuscitation was defined as a lactic acid level < 2.5 mmol/L. Patients were divided into two groups based on presence/absence of OH determined from the lactic acid level immediately before surgery. The incidence of all postoperative organ complications was recorded, and complication rates were compared between groups. Total hospital costs were also compared.

Results: One hundred seventy-seven patients with femur fractures were admitted to the trauma service during this period. Seventy-nine patients met initial criteria for inclusion in the study. Further review excluded 32 patients. Occult hypoperfusion was present in 20 patients before early IM fixation (group 2). Twenty-seven patients were completely resuscitated before early IM fixation (group 1). Injury Severity Scores were similar in both groups. Group 2 had 35 complications in 20 patients, and group 1 had 11 complications in 27 patients. A significant difference was found in incidence of postoperative complications in group 1 (20%) versus group 2 (50%). Group 2 also had a significantly higher proportion of postoperative infections than group 1 (72% vs. 28%, respectively) and higher total hospital costs ($46,469 vs. $23,139).

Conclusion: The presence of OH in trauma patients undergoing early IM fixation of a femur fracture is associated with a twofold higher incidence of postoperative complications. Clinical judgment, not surgical dogma, should guide the timing of IM fixation in these patients. Identifying and correcting OH through relatively simple resuscitative measures may be advantageous in reducing morbidity in the patient with multiple injuries.

Significant debate over the timing of fixation of femoral fractures has been generated over the past 3 decades. The subject becomes more complex when considering the patient with multisystem injuries. Severely injured trauma patients are at increased risk of developing respiratory complications (RC) and multiple system organ failure (MSOF). The importance of correcting hemodynamic parameters early in the course of treatment has been highlighted in numerous studies. 1a,1b The timing of fixation, thus, should depend on factors that will maximize patient benefit.

Reports in the 1960s through the 1970s recommended that intramedullary (IM) fixation of isolated femoral shaft fractures should be delayed until 3 to 7 days postinjury after observation for complications. 2 It has even been reported that delayed treatment for up to 7 to 21 days results in quicker healing. 3 Further studies have demonstrated that the benefits of early fracture fixation can be seen with only a 2- to 4-day delay between initial injury and fixation, provided adequate resuscitation has been achieved before fixation. 4,5 Bone et al. (1994) demonstrated a twofold reduction in mortality in trauma patients with multiple injuries and with an Injury Severity Score (ISS) > 18 who had their fractures fixed early in treatment. Delays in stabilization of the fracture have been shown to result in an increased incidence of the adult respiratory distress syndrome (ARDS), fat embolism, and pneumonia, as well as longer hospital stays, an increase in the number of intensive care unit days and in the total cost of hospital care. 6–9

Further study has shown that in the trauma patient with multiple injuries (ISS > 18), immediate stabilization of the femoral shaft fracture within 24 hours is essential. 8 This finding has led many institutions to treat femoral fractures urgently, often without sufficient correction of acidosis. Although stabilization of blood pressure with fluid resuscitation is accomplished before surgery, occult end-organ hypoperfusion may still exist.

It has been proposed that organ damage in critical illness is due to inadequate oxygen delivery, often exacerbated by a level of tissue oxygen extraction that fails to satisfy metabolic demands. 10–12 Tissue hypoxia after injury is largely responsible for subsequent RC and MSOF). 1b,10 Tissue oxygen debt results in increasing anaerobic metabolism and is accompanied by increases in serum lactic acid (LA) levels. 12,13 LA levels can be used as an index of oxygen debt in end organ tissues. Definitive correlation between blood lactate levels and the development of circulatory septic shock has been reported. 14 Blow et al. 1b demonstrated that persistent occult hypoperfusion (OH) (lactate ≥ 2.5 mmol/L) after the first 24 hours of resuscitation was associated with increased morbidity and mortality after severe trauma. Furthermore, the authors showed that early identification and treatment of OH in the first 24 hours after severe trauma led to a marked diminution in RC, MSOF, and mortality in these patients. 1b

Early fixation of femur fractures (especially with IM nailing) in the presence of OH may contribute to perpetuation of the systemic inflammatory response and increase the likelihood of postoperative complications. If femur fracture fixation is delayed until complete resuscitation is accomplished, a decrease in the incidence of postoperative complications caused by tissue hypoxia and ischemic injury may be identified. The outcome of identifying and correcting OH before early fixation of femoral fractures has not been investigated.

The present study will attempt to determine whether failure to correct OH before early femoral fracture fixation is associated with increased postoperative complications. The hypothesis is that patients who undergo IM fixation of their femoral fractures within 24 hours before correction of OH will have an increased incidence of postoperative complications (ARDS, MSOF, RC, infections).

From the Trauma Service, Department of Surgery, University of Virginia Health System, Charlottesville, Virginia.

Address for reprints: Jeffrey S. Young, MD, Department of Surgery, University of Virginia Health System, Post Office Box 10005, Charlottesville, VA 22906-0005.

Submitted for publication December 7, 1998.

Accepted for publication September 24, 1999.

© 2000 Lippincott Williams & Wilkins, Inc.