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A proposed new mechanism of traumatic aortic rupture
ABSTRACTS
requested for patients with 0 to 3 + microscopic hematuria and no loin t e n d e r n e s s or m a s s , 140 {89%) showed no injury, and the remaining 17 (11%) uncovered only minor degrees of injury. In contrast, of the 176 patients with 4 + to gross hematuria or loin signs and hematuria, 74 (42%) had abnormal IVPs, and all i4 patients requiring surgery were in this group. It was concluded that the IVP has negligible influence on the management of children with minor degrees of asymptomatic hematuria after blunt trauma. However, a preoperative IVP is recommended in all hemodynamically stable trauma patients going to laparotomy for suspected injuries to other viscera. In addition, the a u t h o r s r e c o m m e n d a conservative approach to the management of blunt renal injuries, with surgery reserved for signs of ongoing hemorrhage from a severely injured kidney.
Michael Kohn, MD
aortic aneurysm; aortic rupture; trauma, thoracic
A proposed n e w m e c h a n i s m of t r a u m a t i c aortic rupture Crass JR, Cohen AM, Motta AO, et al
Radiology 176:645-649 Sep 1990
A new theory for the traumatic rupture of the thoracic aorta has been proposed called the "Osseous Pinch." This theory postulates that the aorta is pinched between the vertebral bodies and the clavicle, sternum, and first ribs during sudden chest compression in abrupt deceleration. The chest skeleton of a cadaver was reconstructed with wires, allowing the ribs and sternum to move only in the physiologic manner. A model of the aorta c o n s t r u c t e d with Play-Doh® was placed in the thoracic cavity in anatomic position. The ribs then were compressed, forcing them to rotate about their axes and compress the aorta b e t w e e n the v e r t e b r a l bodies and the manubrium and medial clavicle. The natural inferior/ posterior rotation of the rib cage caused the clavicle and manubrium 162/703
to pinch the model aorta and shear it against the anterior vertebral bodies at the level just distal to the takeoff of the left subclavian. The majority of blunt thoracic aortic dissections occur in the level of the aortic isthmus.
David Rosenberg, MD
diagnostic peritoneal lavage
Diagnostic peritoneal lavage: A c c u r a c y in predicting n e c e s s a r y l a p a r o t o m y following blunt and penetrating t r a u m a Henneman PL, Marx JA, Moore EE, et al
J Trauma 30:1345-1355 Nov 1990
This retrospective study evaluated the accuracy of diagnostic peritoneal lavage (DPL) in predicting the need for laparotomy following blunt and penetrating trauma. Paramedic trip sheets, emergency department records, hospital charts, operative notes, autopsy records, and follow-up clinic visits were reviewed for 944 patients undergoing 975 DPLs for injury to the abdomen, flank, and lower chest. Criteria for a p o s i t i v e DPL after blunt abdominal trauma were a s p i r a t i o n of 10 mL gross blood, 100,000/mm 3 or more RBCs, 500/ m m 3 or more WBCs, amylase 200 U/L or more, or bacteria present. DPL criteria for stab wounds to the lower chest and tangential gunshot wounds were aspiration of 1 mL gross blood, 5,000 mm/3 or more RBCs, 500 mm/3 or more WBCs, amylase of 200 U/L or more, or bacteria present. Laparotomies were deemed necessary or unnecessary by panel review of the operative or autopsy reports; reviewers were blinded to clinical circumstances and DPL results. Positive lavages were considered falsely positive if the patient had an intra-abdominal injury that did not require repair or if the patient did well clinically w i t h o u t laparotomy. Initial DPL in 608 patients sustaining blunt t r a u m a had a sensitivity of 87%, specificity of 97%, accuracy of 95%, positive predictive value (PPV) of 85%, and negative predictive-value
Annals of EmergencyMedicine
(NPV) of 97%. There were 19 unnecessary laparotomies, eight due to false-positive lavages and 11 due to clinical impression. Initial DPL in 336 patients with penetrating trauma had a sensitivity of 87%, specificity of 89%, accuracy of 89%, PPV of 75%, and NPV of 95%. Fifty-six patients u n d e r w e n t l a p a r o t o m y ; 19 were unnecessary and nine were due to false-positive lavages. One hundred seventy-four DPLs were performed in 172 patients with stab wounds to the lower chest. Fifty-four patients underwent laparotomy, with 14 false-positive lavages and two false-negatives. Of 30 DPLs for gunshot wounds with unclear penetration into the peritoneum, there were three false-positives. When using final lavage results on the 944 patients, DPL had a sensitivity of 91%, specificity of 94%, accuracy of 93%, PPV of 80%, and NPV of 98% in predicting i n t r a - a b d o m i n a l injury requiring surgical repair. It was conc l u d e d t h a t DPL a c c u r a t e l y and safely differentiates p a t i e n t s requiring surgical repair from those who do not.
Laurie Vande Krol, MD
motion sickness; phenytoin
Use of phenytoin in the prevention of motion sickness Chelen W, Kabrisky M, Hatsell C, et a!
Aviat Space Environ Med 61:1022-1025 Nov 1990
A placebo-controlled, double-blind, crossover, pilot study to determine the efficacy of the anticonvulsant phenytoin for the prevention of motion sickness was performed. In the study, seven healthy male subjects were subjected to acute Coriolis motion stimulus to induce motion sickness, and the efficacy of an anticonvulsant dose of phenytoin (15 mg/kg oral l o a d i n g dose g i v e n o v e r 20 hours) in the prevention and treatm e n t of m o t i o n sickness was assessed. The dilantin-treated group had a more than fourfold improvement in efficacy over any currently available single agent, with a mean 20:6 June 1991
requested for patients with 0 to 3 + microscopic hematuria and no loin t e n d e r n e s s or m a s s , 140 {89%) showed no injury, and the remaining 17 (11%) uncovered only minor degrees of injury. In contrast, of the 176 patients with 4 + to gross hematuria or loin signs and hematuria, 74 (42%) had abnormal IVPs, and all i4 patients requiring surgery were in this group. It was concluded that the IVP has negligible influence on the management of children with minor degrees of asymptomatic hematuria after blunt trauma. However, a preoperative IVP is recommended in all hemodynamically stable trauma patients going to laparotomy for suspected injuries to other viscera. In addition, the a u t h o r s r e c o m m e n d a conservative approach to the management of blunt renal injuries, with surgery reserved for signs of ongoing hemorrhage from a severely injured kidney.
Michael Kohn, MD
aortic aneurysm; aortic rupture; trauma, thoracic
A proposed n e w m e c h a n i s m of t r a u m a t i c aortic rupture Crass JR, Cohen AM, Motta AO, et al
Radiology 176:645-649 Sep 1990
A new theory for the traumatic rupture of the thoracic aorta has been proposed called the "Osseous Pinch." This theory postulates that the aorta is pinched between the vertebral bodies and the clavicle, sternum, and first ribs during sudden chest compression in abrupt deceleration. The chest skeleton of a cadaver was reconstructed with wires, allowing the ribs and sternum to move only in the physiologic manner. A model of the aorta c o n s t r u c t e d with Play-Doh® was placed in the thoracic cavity in anatomic position. The ribs then were compressed, forcing them to rotate about their axes and compress the aorta b e t w e e n the v e r t e b r a l bodies and the manubrium and medial clavicle. The natural inferior/ posterior rotation of the rib cage caused the clavicle and manubrium 162/703
to pinch the model aorta and shear it against the anterior vertebral bodies at the level just distal to the takeoff of the left subclavian. The majority of blunt thoracic aortic dissections occur in the level of the aortic isthmus.
David Rosenberg, MD
diagnostic peritoneal lavage
Diagnostic peritoneal lavage: A c c u r a c y in predicting n e c e s s a r y l a p a r o t o m y following blunt and penetrating t r a u m a Henneman PL, Marx JA, Moore EE, et al
J Trauma 30:1345-1355 Nov 1990
This retrospective study evaluated the accuracy of diagnostic peritoneal lavage (DPL) in predicting the need for laparotomy following blunt and penetrating trauma. Paramedic trip sheets, emergency department records, hospital charts, operative notes, autopsy records, and follow-up clinic visits were reviewed for 944 patients undergoing 975 DPLs for injury to the abdomen, flank, and lower chest. Criteria for a p o s i t i v e DPL after blunt abdominal trauma were a s p i r a t i o n of 10 mL gross blood, 100,000/mm 3 or more RBCs, 500/ m m 3 or more WBCs, amylase 200 U/L or more, or bacteria present. DPL criteria for stab wounds to the lower chest and tangential gunshot wounds were aspiration of 1 mL gross blood, 5,000 mm/3 or more RBCs, 500 mm/3 or more WBCs, amylase of 200 U/L or more, or bacteria present. Laparotomies were deemed necessary or unnecessary by panel review of the operative or autopsy reports; reviewers were blinded to clinical circumstances and DPL results. Positive lavages were considered falsely positive if the patient had an intra-abdominal injury that did not require repair or if the patient did well clinically w i t h o u t laparotomy. Initial DPL in 608 patients sustaining blunt t r a u m a had a sensitivity of 87%, specificity of 97%, accuracy of 95%, positive predictive value (PPV) of 85%, and negative predictive-value
Annals of EmergencyMedicine
(NPV) of 97%. There were 19 unnecessary laparotomies, eight due to false-positive lavages and 11 due to clinical impression. Initial DPL in 336 patients with penetrating trauma had a sensitivity of 87%, specificity of 89%, accuracy of 89%, PPV of 75%, and NPV of 95%. Fifty-six patients u n d e r w e n t l a p a r o t o m y ; 19 were unnecessary and nine were due to false-positive lavages. One hundred seventy-four DPLs were performed in 172 patients with stab wounds to the lower chest. Fifty-four patients underwent laparotomy, with 14 false-positive lavages and two false-negatives. Of 30 DPLs for gunshot wounds with unclear penetration into the peritoneum, there were three false-positives. When using final lavage results on the 944 patients, DPL had a sensitivity of 91%, specificity of 94%, accuracy of 93%, PPV of 80%, and NPV of 98% in predicting i n t r a - a b d o m i n a l injury requiring surgical repair. It was conc l u d e d t h a t DPL a c c u r a t e l y and safely differentiates p a t i e n t s requiring surgical repair from those who do not.
Laurie Vande Krol, MD
motion sickness; phenytoin
Use of phenytoin in the prevention of motion sickness Chelen W, Kabrisky M, Hatsell C, et a!
Aviat Space Environ Med 61:1022-1025 Nov 1990
A placebo-controlled, double-blind, crossover, pilot study to determine the efficacy of the anticonvulsant phenytoin for the prevention of motion sickness was performed. In the study, seven healthy male subjects were subjected to acute Coriolis motion stimulus to induce motion sickness, and the efficacy of an anticonvulsant dose of phenytoin (15 mg/kg oral l o a d i n g dose g i v e n o v e r 20 hours) in the prevention and treatm e n t of m o t i o n sickness was assessed. The dilantin-treated group had a more than fourfold improvement in efficacy over any currently available single agent, with a mean 20:6 June 1991