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Neutrophil-mediated microvascular injury
zation for pain control. Overall, the ratio of supplemental narcotics used by the placebo group versus the indomethacin group was 7.6:1 (P < .005). The mean time to calculus passage was slightly shorter in the indomethacin group (82 versus 89 hours), but this difference was not statistically significant. Our results support the use of indomethacin suppositories in the treatment of recurrent colic secondary to ureteral calculi.
187 Indomethacin for Relief of Acute Renal Colic AB Wolfson, DM Yealy/Hospital of the University of Pennsylvania; University of Pittsburgh Affiliated Residency in Emergency Medicine; Center for Emergency Medicine of Western Pennsylvania, Pittsburgh Early studies have suggested that indomethacin can relieve renal colic by a mechanism of action different from that of narcotics. If effective, indomethacin would offer the potential advantage of avoiding narcotic side effects such as alteration of mental status. We prospectively administered oral indomethacin (50 mg) to 25 nonvomiting patients with acute renal colic due to a documented stone. Eleven patients (group 1) received indomethacin in an unblinded, nonrandomized fashion after failure of oral or parenteral narcotics to relieve pain. In 14 additional patients (group 2), indomethacin was given as the only initial treatment. Pain intensity before and after treatment was reported using a 1-to-10 scale. In group 1 patients, pain decreased from 5.8 + 2.7 to 3.6 + 3.8 (P < .02). Six of the 11 patients reported a decrease in pain intensity of 50% or more, which occurred within 25 + 11 minutes. In no patient did pain increase. In five of the six obtaining relief, pain decreased to a 0 or 1 level. Among the 14 patients in group 2, pain decreased from 7.6 + 1.5 to 4.6 + 4.0 (P < .008). Eight of the 14 reported a decrease in pain intensity of 50% or more, which occurred within 40 + 14 minutes. In five of the eight, pain decreased to a 0 or 1 level. In no patient did pain increase; further analgesia was required in the six patients whose pain did not respond to indomethacin. Patients who responded to indomethacin were discharged on oral indomethacin. All were able to continue with daily activities; only one had returned for further pain control at one week follow-up. Two patients successfully treated further episodes of renal colic at home with oral indomethacin. These promising preliminary observations suggest that placebo-controlled studies are warranted to define the appropriate role for indomethacin and similar agents in the management of acute renal colic. 188 Stabilization of Unstable Pelvic Ring Fractures With Military Anti-Shock Trousers: A Radiographic Assessment CC Huerta, G Polando, J Shall, J Glauser/Emergency Medicine Residency Program, Departments of Orthopaedic Research and Orthopaedic Surgery, Mt Sinai Medical Center of Cleveland, Ohio The benefits of military anti-shock trousers (MAST) in hemodynamically unstable patients with pelvic ring fractures are well documented. However, this literature and EMS guidelines also advocate the use of MAST as a skeletal stabilization device. It is believed that MAST immobilizes the pelvic ring by acting as a large air splint. No study documents, either quantitatively or qualitatively, evidence that MAST can adequately perform this function. Furthermore, the potential for creating new damage, or the aggravation of organ and soft tissue injuries, has not been assessed. This study examines radiographically whether bony stability of the pelvis is achieved by MAST. A cadaveric model was developed and proven to simulate a human unstable pelvic ring fracture. Three cadavers found by radiographic examination to be free of pelvic bone disease or fracture served as models. Five types of unstable pelvic ring fractures, simulating worst case instability, were surgically induced. For the most unstable fractures, both blunt and oblique angle bone cuts were produced. External leg rotation to 90 ° and abduction to 50 ° from midline were used to represent extremes of expected prehospital motion. Anterior-posterior and inlet views with supplemental outlet view documented pelvic ring instability. Radiographic assessment of pelvic ring motion was carried out before and at end-manipulation, both with and without each cadaver in MAST. EMS personnel aided in the application and inflation of MAST to ensure conformity with current protocols. Radiographic evaluation proved MAST was effective in reducing and stabilizing each unstable pelvic ring fracture. With proper MAST inflation, pelvic ring stability under extreme manipulation was maintained. In every fracture type, bony distraction of up to 6 cm was completely reduced with MAST. In addition, with MAST
196/476
inflated, even extreme manipulative force failed to reproduce fracture end-distraction. At no time during MAST use was the fracture overreduced or did pelvic ring collapse result. The authors find radiographic evidence to support the use of MAST in stabilizing the unstable pelvic ring fracture.
189 NeutrophiI-Mediated Microvascular Injury DL Carden, JK Smith, RJ Korthuis/Department of Physiology and Biophysics, Louisiana State University Medical Center; Clinical Department of Emergency Medicine, Schumpert Medical Center, Shreveport, Louisiana Recent studies implicate polymorphonuclear neutrophils in the microvascular injury that occurs on reperfusion of ischemic tissue. Before tissue extravasation and microvascular injury, circulating neutrophils adhere to the microvascular endothelium and become activated. The purpose of our study was to delineate the role of neutrophils in producing microvascular injury in isolated canine gracilis muscle after a prolonged ischemic insult. The effect of neutropenia was examined using specific antisera raised against canine neutrophils. The antineutrophil serum reduced the peripheral white blood cell count to less than 5% of control values. In addition, the role of neutrophil adherence was addressed by administering a monoclonal antibody specific for the t~-chain of the neutrophil CD18 complex (IB) 4" By binding with the CD18 complex, IB4 interferes with neutrophil adherence and extravasation. The solvent drag reflection coefficient (o) was used as an index of the severity of microvascular injury and is a sensitive measure of changes in microvascular permeability. The o was determined for the following conditions: control (no ischemia), reperfusion after four hours of ischemia, reperfusion after four hours of ischemia in neutropenic dogs, and reperfusion after four hours of ischemia in dogs treated with IB4.
Group Control Ischemia/reperfusion(I/R) I/R, (neutrophildepletion) I/R, (IB4)
o 0.99 _+.08 0.60 ± .02" 0.99 ± .05 1.0 + .03
Reperfusion after four hours of ischemia resulted in a significant decrease in o, indicating a dramatic increase in mierovascular permeability. Neutrophil depletion or prevention of neutrophil adherence prevented the increase in microvascular permeability seen in untreated animals. The results of our study indicate that neutrophils mediate postischemic microvascular injury and that neutrophil adherence to the microvascular endothelium is a prerequisite for the production of this injury.
190 The Detrimental Effects of IV Crystalloid After Aortotomy in the Swine WH Bickell, SP Bruttig, CE Wade, P Maningas, GA Millnamow/ Letterman Army Institute of Research, Presidio of San Francisco, California; Trauma Service, Saint Francis Hospital, Tulsa, Oklahoma The objective of our study was to test the hypothesis that after aortotomy, attempting to rapidly replace the estimated blood volume deficit with IV crystalloid will increase hemorrhage and decrease survival. Sixteen anesthetized Yorkshire swine underwent splenectomy and stainless-steel wire placement in the anterior infrarenal aorta and were instrumented with Swan-Ganz and carotid artery catheters. The wire was pulled, producing a 5-mm aortotomy and spontaneous intraperitoneal hemorrhage. The animals were randomly assigned to the untreated control group (eight) or the lactated Ringer's group (eight), which received 80 mL/kg Ringer's IV. The lactated Ringer's infusion was initiated 6.5 minutes after aortotomy and infused at a rate of 8 mL/kg/min. From baseline to five minutes after aortotomy, there was a profound decrease in cardiac output, mean arterial pressure, and mean pulmonary artery pressure in both groups. The administration of lactated Ringer's produced a biphasic hemodynamic response as cardiac output, mean arterial pressure, and mean pulmonary artery pressure significantly (P < .05), increased, and then subsequently fell significantly (P < .05) below that of untreated control animals. The volume of hemorrhage and the mortality rate were significantly (P < .05) increased in the Ringer's treatment group (2,142 + 178 versus 783 + 85 mL, and eight of eight versus zero of eight, respectively). From these data, we conclude that in this model of uncontrolled arterial hemorrhage resulting from abdominal aortotomy, the rapid administration of IV lactated Ringer's significantly
Annals of Emergency Medicine
18:4 April 1989
187 Indomethacin for Relief of Acute Renal Colic AB Wolfson, DM Yealy/Hospital of the University of Pennsylvania; University of Pittsburgh Affiliated Residency in Emergency Medicine; Center for Emergency Medicine of Western Pennsylvania, Pittsburgh Early studies have suggested that indomethacin can relieve renal colic by a mechanism of action different from that of narcotics. If effective, indomethacin would offer the potential advantage of avoiding narcotic side effects such as alteration of mental status. We prospectively administered oral indomethacin (50 mg) to 25 nonvomiting patients with acute renal colic due to a documented stone. Eleven patients (group 1) received indomethacin in an unblinded, nonrandomized fashion after failure of oral or parenteral narcotics to relieve pain. In 14 additional patients (group 2), indomethacin was given as the only initial treatment. Pain intensity before and after treatment was reported using a 1-to-10 scale. In group 1 patients, pain decreased from 5.8 + 2.7 to 3.6 + 3.8 (P < .02). Six of the 11 patients reported a decrease in pain intensity of 50% or more, which occurred within 25 + 11 minutes. In no patient did pain increase. In five of the six obtaining relief, pain decreased to a 0 or 1 level. Among the 14 patients in group 2, pain decreased from 7.6 + 1.5 to 4.6 + 4.0 (P < .008). Eight of the 14 reported a decrease in pain intensity of 50% or more, which occurred within 40 + 14 minutes. In five of the eight, pain decreased to a 0 or 1 level. In no patient did pain increase; further analgesia was required in the six patients whose pain did not respond to indomethacin. Patients who responded to indomethacin were discharged on oral indomethacin. All were able to continue with daily activities; only one had returned for further pain control at one week follow-up. Two patients successfully treated further episodes of renal colic at home with oral indomethacin. These promising preliminary observations suggest that placebo-controlled studies are warranted to define the appropriate role for indomethacin and similar agents in the management of acute renal colic. 188 Stabilization of Unstable Pelvic Ring Fractures With Military Anti-Shock Trousers: A Radiographic Assessment CC Huerta, G Polando, J Shall, J Glauser/Emergency Medicine Residency Program, Departments of Orthopaedic Research and Orthopaedic Surgery, Mt Sinai Medical Center of Cleveland, Ohio The benefits of military anti-shock trousers (MAST) in hemodynamically unstable patients with pelvic ring fractures are well documented. However, this literature and EMS guidelines also advocate the use of MAST as a skeletal stabilization device. It is believed that MAST immobilizes the pelvic ring by acting as a large air splint. No study documents, either quantitatively or qualitatively, evidence that MAST can adequately perform this function. Furthermore, the potential for creating new damage, or the aggravation of organ and soft tissue injuries, has not been assessed. This study examines radiographically whether bony stability of the pelvis is achieved by MAST. A cadaveric model was developed and proven to simulate a human unstable pelvic ring fracture. Three cadavers found by radiographic examination to be free of pelvic bone disease or fracture served as models. Five types of unstable pelvic ring fractures, simulating worst case instability, were surgically induced. For the most unstable fractures, both blunt and oblique angle bone cuts were produced. External leg rotation to 90 ° and abduction to 50 ° from midline were used to represent extremes of expected prehospital motion. Anterior-posterior and inlet views with supplemental outlet view documented pelvic ring instability. Radiographic assessment of pelvic ring motion was carried out before and at end-manipulation, both with and without each cadaver in MAST. EMS personnel aided in the application and inflation of MAST to ensure conformity with current protocols. Radiographic evaluation proved MAST was effective in reducing and stabilizing each unstable pelvic ring fracture. With proper MAST inflation, pelvic ring stability under extreme manipulation was maintained. In every fracture type, bony distraction of up to 6 cm was completely reduced with MAST. In addition, with MAST
196/476
inflated, even extreme manipulative force failed to reproduce fracture end-distraction. At no time during MAST use was the fracture overreduced or did pelvic ring collapse result. The authors find radiographic evidence to support the use of MAST in stabilizing the unstable pelvic ring fracture.
189 NeutrophiI-Mediated Microvascular Injury DL Carden, JK Smith, RJ Korthuis/Department of Physiology and Biophysics, Louisiana State University Medical Center; Clinical Department of Emergency Medicine, Schumpert Medical Center, Shreveport, Louisiana Recent studies implicate polymorphonuclear neutrophils in the microvascular injury that occurs on reperfusion of ischemic tissue. Before tissue extravasation and microvascular injury, circulating neutrophils adhere to the microvascular endothelium and become activated. The purpose of our study was to delineate the role of neutrophils in producing microvascular injury in isolated canine gracilis muscle after a prolonged ischemic insult. The effect of neutropenia was examined using specific antisera raised against canine neutrophils. The antineutrophil serum reduced the peripheral white blood cell count to less than 5% of control values. In addition, the role of neutrophil adherence was addressed by administering a monoclonal antibody specific for the t~-chain of the neutrophil CD18 complex (IB) 4" By binding with the CD18 complex, IB4 interferes with neutrophil adherence and extravasation. The solvent drag reflection coefficient (o) was used as an index of the severity of microvascular injury and is a sensitive measure of changes in microvascular permeability. The o was determined for the following conditions: control (no ischemia), reperfusion after four hours of ischemia, reperfusion after four hours of ischemia in neutropenic dogs, and reperfusion after four hours of ischemia in dogs treated with IB4.
Group Control Ischemia/reperfusion(I/R) I/R, (neutrophildepletion) I/R, (IB4)
o 0.99 _+.08 0.60 ± .02" 0.99 ± .05 1.0 + .03
Reperfusion after four hours of ischemia resulted in a significant decrease in o, indicating a dramatic increase in mierovascular permeability. Neutrophil depletion or prevention of neutrophil adherence prevented the increase in microvascular permeability seen in untreated animals. The results of our study indicate that neutrophils mediate postischemic microvascular injury and that neutrophil adherence to the microvascular endothelium is a prerequisite for the production of this injury.
190 The Detrimental Effects of IV Crystalloid After Aortotomy in the Swine WH Bickell, SP Bruttig, CE Wade, P Maningas, GA Millnamow/ Letterman Army Institute of Research, Presidio of San Francisco, California; Trauma Service, Saint Francis Hospital, Tulsa, Oklahoma The objective of our study was to test the hypothesis that after aortotomy, attempting to rapidly replace the estimated blood volume deficit with IV crystalloid will increase hemorrhage and decrease survival. Sixteen anesthetized Yorkshire swine underwent splenectomy and stainless-steel wire placement in the anterior infrarenal aorta and were instrumented with Swan-Ganz and carotid artery catheters. The wire was pulled, producing a 5-mm aortotomy and spontaneous intraperitoneal hemorrhage. The animals were randomly assigned to the untreated control group (eight) or the lactated Ringer's group (eight), which received 80 mL/kg Ringer's IV. The lactated Ringer's infusion was initiated 6.5 minutes after aortotomy and infused at a rate of 8 mL/kg/min. From baseline to five minutes after aortotomy, there was a profound decrease in cardiac output, mean arterial pressure, and mean pulmonary artery pressure in both groups. The administration of lactated Ringer's produced a biphasic hemodynamic response as cardiac output, mean arterial pressure, and mean pulmonary artery pressure significantly (P < .05), increased, and then subsequently fell significantly (P < .05) below that of untreated control animals. The volume of hemorrhage and the mortality rate were significantly (P < .05) increased in the Ringer's treatment group (2,142 + 178 versus 783 + 85 mL, and eight of eight versus zero of eight, respectively). From these data, we conclude that in this model of uncontrolled arterial hemorrhage resulting from abdominal aortotomy, the rapid administration of IV lactated Ringer's significantly
Annals of Emergency Medicine
18:4 April 1989