R. D. Levy

The effect of pH on chemiluminescence of different probes exposed to superoxide and singlet oxygen generators

The compromised optima for high intensity chemiluminescence (CL), using superoxide generators, were all above pH 9.0 for the CL probes luminol and lucigenin. With luminol the optima were at pH 9.0 and 9.4 for the generators KO2 and hypoxanthine/xanthine oxidase (HX/XO), respectively. Lucigenin, with the same generators, produced optima at pH 9.5 and 10.0, respectively. The probe methyl-Cypridina-luciferin analogue (MCLA) produced optima closer to neutral pH, which is preferred for physiological assessments. MCLA had optima at pH 6.0, 8.7 and 9.5 with KO2 and with HX/XO optima at pH 4.8, 6.0, 7.0 and 8.7. When CL was assessed at physiological pH, MCLA observed superoxide radicals with a sensitivity of 100- and 330-fold more than luminol or luicigenin respectively. For singlet oxygen, the sensitivity of MCLA at this pH was 45- and 5465-fold more than for the said probes respectively. H2O2 did not elicit CL between pH 4 and 9.5 with any of the probes and did not influence the production of superoxide or singlet oxygen when co-assessed. Therefore CL could only be obtained when enzymes were used as converters. The optima for the enzyme-conversion system horseradish peroxidase (HRP)/H2O2, and luminol, were at pH 8.0 and 9.2. Lucigenin and HRP/H2O2 also had a biphasic CL profile with optima at pH 7.4 and 9.6. MCLA and HRP/H2O2 had five optima, with the major ones at pH 6.1 and beyond 10. The optima for the myeloperoxidase/H2O system were at 8.6 and beyond 10.0 when luminol and 0.15 mol/L NaBr were used.

Selective surgical management of zone II gunshot injuries of the neck : A prospective study

BACKGROUND The management of penetrating neck trauma remains controversial, with many studies supporting either mandatory exploration or selective conservatism. METHODS AND RESULTS This is a prospective study of 75 patients with gunshot injuries to zone II of the neck. Forty patients (53.3%) underwent immediate exploration because of clinical indications or positive initial investigations. A 7.5% incidence of unnecessary explorations, a 5% mortality rate, and average hospital stay of 10.5 days were noted. Thirty-five patients with negative clinical or investigational findings underwent observation with constant monitoring. A 5.7% incidence of missed injuries, no mortality, and an average hospital stay of 3.5 days were noted for these patients. CONCLUSIONS We suggest that conservative management in gunshot injuries confined to zone II of the neck selectively supplemented by appropriate investigations is a viable proposition in this type of injury. Further contemporary studies reporting specifically on this injury will enable us to reach statistically significant conclusions.

Penetrating injuries of the iliac arteries : a south African experience

BACKGROUND We did a retrospective study of 62 patients with penetrating injuries of the iliac arteries. METHODS The cause of injury was gunshot wound in 85.5% and stabbing in 14.5%. The arterial repair was achieved by various means: lateral arteriorrhaphy, end-to-end anastomosis, and polytetrafluoroethylene interposition grafts. RESULTS There was a 42% mortality rate from exsanguination or secondary coagulopathy directly related to the arterial injury. Persistent shock, resuscitative thoracotomy, free intraperitoneal hemorrhage, and the number of vascular injuries were directly related to mortality. CONCLUSIONS A high index of suspicion, aggressive resuscitation, and prompt surgery are necessary to improve the chances of surviving this ominous injury.

Gunshot Injuries of the Head of the Pancreas: Conservative Approach

Abstract. This study is comprised of 48 patients with gunshot injuries of the head of the pancreas, many of which were high velocity injuries. The purpose of this study was to evaluate our management policy for these injuries based on our recent wide experience. Patients with grade II and III injuries underwent conservative surgery, with 0% and 21% postoperative mortality, respectively, directly related to the pancreatic injury. For patients in whom the duodenum was involved, pyloric exclusion was applied depending on the grade of the duodenal injury. We concluded that moderate gunshot injuries of the head of the pancreas (grade II) can be safely treated by débridement and suture repair, with or without drainage. Severe (grade IV) injuries warrant a pancreaticoduodenectomy. Most grade III injuries can be treated by débridement and drainage unless an associated severe duodenal injury is present, in which case resection may be indicated.

Arterial gunshot injuries of the extremities: a South African experience.

This is a retrospective study of 173 patients with gunshot injuries of the major arteries of the extremities. A selective policy for the use of angiography was followed. The arterial repair was achieved by various means: primary end-to-end anastomosis, vein interposition graft, and polytetrafluoroethylene (Teflon) interposition grafts. Overall, there were nine amputations in the lower limb. Ninety-eight percent of the patients had a palpable pulse on discharge. There were 3 preoperative deaths, 1 intraoperative death, and 5 postoperative deaths (overall perioperative mortality, 3.5%). We conclude that the results of vascular extremity gunshot injuries are satisfactory when standard methods of management are used. Morbidity and mortality can be further reduced by prompt admission to appropriate centers.

Penetrating injuries of the brachial artery

This is a retrospective study of 72 patients with non-iatrogenic penetrating injuries of the brachial artery treated between 1991 and 1993. The mechanism of injury was stabbing in 39 per cent, a bullet in 51 per cent, pellets in 4 per cent and a dog bite in 6 per cent. We believe that angiography is rarely indicated, as in all our patients the diagnosis was made on clinical grounds. The proximity of the injury to neurovascular bundles was a poor predictor of arterial injury. One month after discharge 95 per cent of the patients had palpable distal pulses. Long-term morbidity is mainly attributed to associated nerve injuries.

Gunshot injuries of the liver: the Baragwanath experience.

BACKGROUND This study comprised 304 patients with gunshot injuries of the liver, many of which from high-velocity firearms. The purpose of this study is to evaluate our management policy in gunshot injuries of the liver in light of our recent wider experience. METHODS All grade I and II injuries and most grade III injuries were managed by simple operative measures, without postoperative mortality directly related to the liver trauma. RESULTS Grade III, IV, and V injuries had 8.5%, 52%, and 16% resectional debridement rates and 8.5%, 38%, and 84% perihepatic packing rates, respectively. In the resectional debridement group the postoperative mortality rate was 15% (half the deaths were directly caused by the hepatic injury). The postoperative mortality rate in the perihepatic packing group was 31.5% of which 45% of deaths were due to ongoing bleeding, 27.5% to sepsis, and 27.5% to associated trauma. The septic complications were less common when packs were removed early. CONCLUSIONS We suggest that resectional debridement and perihepatic packing should be liberally applied in the most severe grade III, most grade IV, and grade V gunshot injuries of the liver and that perihepatic packing should be removed as early as the physiologic derangements are corrected. Our experience with grade VI injuries is very limited, and their management should be studied in larger series.

Gunshot injuries of the abdominal aorta: a continuing challenge

This is a retrospective study of 57 patients with gunshot injuries of the abdominal aorta. The aortic repair was achieved by various means: lateral aortorraphy, patch aortoplasty and graft insertion. There was an 85 per cent mortality rate from bleeding or secondary coagulopathy directly related to the aortic injuries. The need for resuscitative thoracotomy, shock, lack of response to fluid resuscitation and intraperitoneal bleeding were directly related to mortality. We feel that shortening of prehospital transfer time will increase the absolute number of patients surviving this grave injury.