Charles B. Rodning

Does increased emergency medical services prehospital time affect patient mortality in rural motor vehicle crashes? A statewide analysis.

BACKGROUND Fatality rates from rural vehicular trauma are almost double those found in urban settings. It has been suggested that increased prehospital time is a factor that adversely affects fatality rates in rural vehicular trauma. By linking and analyzing Alabamas statewide prehospital data, emergency medical services (EMS) prehospital time was assessed for rural and urban vehicular crashes. METHODS An imputational methodology permitted linkage of data from police motor vehicle crash (MVC) and EMS records. MVCs were defined as rural or urban by crash location using the United States Census Bureau criteria. Areas within Alabama that fell outside the Census Bureau definition of urban were defined as rural. Prehospital data were analyzed to determine EMS response time, scene time, and transport time in rural and urban settings. RESULTS Over a 2-year period from January 2001 through December 2002, data were collected from EMS Patient Care Reports and police crash reports for the entire state of Alabama. By using an imputational methodology and join specifications, 45,763 police crash reports were linked to EMS Patient Care Reports. Of these, 34,341 (75%) were injured in rural settings and 11,422 (25%) were injured in urban settings. A total of 714 mortalities were identified, of which 611 (1.78%) occurred in rural settings and 103 (.90%) occurred in urban settings (P < .0001). When mortalities occurred, the mean EMS response time in rural settings was 10.67 minutes and 6.50 minutes in urban settings (P < .0001). When mortalities occurred, the mean EMS scene time in rural settings was 18.87 minutes and 10.83 minutes in urban settings (patients who were dead on scene and extrication patients were excluded from both settings) (P < .0001). When mortalities occurred, the mean EMS transport time in rural settings was 12.45 minutes and 7.43 minutes in urban settings (P < .0001). When mortalities occurred, the overall mean prehospital time in rural settings was 42.0 minutes and 24.8 minutes in urban settings (P < .0001). The mean EMS response time for rural MVCs with survivors was 8.54 minutes versus a mean of 10.67 minutes with mortalities (P < .0001). The mean EMS scene time for rural MVCs with survivors was 14.81 minutes versus 18.87 minutes with mortalities (patients who were dead on scene and extrication patients were excluded) (P = .0014). CONCLUSIONS Based on this statewide analysis of MVCs, increased EMS prehospital time appears to be associated with higher mortality rates in rural settings.

Technical parameters of immunostaining of osmicated tissue in epoxy sections.

The development of the labeled and unlabeled antibody enzyme methods and their application at the light and electron microscopic level have led to the widespread use of postembedding staining techniques of a wide variety of antigens. An important step in the postembedding staining technique is the “etching” or pretreatment of the plastic section with an agent to enhance the binding of specific primary antibody to antigen in the section. Sodium ethoxide (14) or alcoholic sodium hydroxide (8) both of which physically dissolve polymerized epoxy resin, were initially used to facilitate tinctorial staining (8, 14) and later by Lange (9, 10) to enhance the immunofluorescence for glucagon in plastic sections of pancreatic islets. Hydrogen peroxide has been used to bleach osmium from plastic sections and to enhance staining for glycoproteins at the ultrastructural level (13, 15, 19), but was first used by Nakane (18) in 1971 to enhance immunostaining at the ultrastructural level for growth hormone and prolactin in osmicated sections of rat pituitary. Using the unlabeled antibody enzyme method, Moriarty and Halmi (17) and Erlandsen et al. (5) showed that intensity of immunostaining in the postembedding technique was enhanced if sections of aldehyde fixed tissue were briefly exposed to hydrogen peroxide before application of immunoreagents. The successful use of hydrogen peroxide and alcoholic sodium hydroxide in the enhancement of immunostaining has led to their widespread adoption as an essential step in postembedding staining despite the fact that there is relatively little information available as to what effect these agents may have on the plastic resin or on the stability and extraction of antigens from the tissue sections. In this report the effect of various types of “etching” or pretreatment agents on the surface topography of the plastic sections has been investigated and has been correlated with the immunostaining for lysozyme within rat Paneth cells and with the extraction of Na’25! by these agents from cured epoxy resin.

Ventral/incisional abdominal herniorrhaphy by fascial partition/release.

Ventral/incisional abdominal hernias following celiotomies continue to be a vexing problem for both patients and general and plastic and reconstructive surgeons, since no universally applicable preventive or reconstructive techniques have evolved. With reference to reconstruction, for example, primary repair is associated with a high incidence of recurrence; utilization of synthetic mesh is susceptible to extrusion, infection, and intestinal fistulization; and employment of truncal or extremity, free or rotational, myofascial flaps is associated with the morbidity of the procedure per se. By contrast, the use of fascial partition/release of the components of the abdominal wall employing bilateral parasagittal relaxing incisions in the obliquus externus abdominis and/or transversus abdominis fascia facilitates coaptation of the linea alba and obviates the aforementioned morbidity. This technique was utilized electively in seven adult patients with large defects of the anterior abdominal wall. In addition, for two patients, synthetic nonabsorbable mesh was applied superficial to the midline fascial closure. During a mean follow-up interval of 18 months (range 6 to 36 months), each patient healed per primum without evidence of eventration or herniation. The theoretic and pragmatic advantages of this technique are discussed. The use of fascial partition/release for reconstruction of abdominal wall defects should be part of the armamentarium of all herniotomists.

Immunohistochemical localization of IgA antigens in sections embedded in epoxy resin.

Antigenic determinants for both heavy and light chains of IgA in immunocytes and lysozyme in Paneth cells were successfully identified by immunohistochemistry in sections of tissue embedded in epoxy resin. Successful staining for immunoglobulin and lysozyme required the removal of the epoxy resin prior to application of the immunochemical reagents and was independent of the type of epoxy resin employed. Localization of immunoglobulin antigens depended upon the utilization of either chemical fixation other than glutaraldehyde or physical fixation by freeze-drying. Lysozyme was detected regardless of the fixation process used. Optimal preservation of antigenicity for immunoglobulin and lysozyme was ob-

Immunocytochemical identification and localization of immunoglobulin A within Paneth cells of the rat small intestine.

Light microscopic immunocytochemistry was used to identify Paneth cells by their lysozyme content and to detect immunoglobulin antigens within a subpopulation of these cells. Antisera specific for the heavy chains of rat or human immunoglobulin A and for immunoglobulin light chain antigens produced specific staining of rat Paneth cells. The distribution of immunoglobulin staining varied between adjacent Paneth cells in the same crypt and between Paneth cells in adjacent crypts, as well as between Paneth cell populations of different animals. No staining of rat Paneth cells was detected using antisera specific for the heavy chain of immunoglobulins G or M. The specific staining of Paneth cells for immunoglobulin A and light chain antigens was blocked by absorption of each antiserum with its respective purified antigen. Absorption of these antisera with purified rat lysozyme did not affect staining and thereby eliminated the possibility of immunologic cross-reactivity between lysozyme and immunoglobulin antigens. It is suggested, in light of current concepts of Paneth cell function, that the immunoglobulin staining of Paneth cells may reflect their ability to phagocytize immunoglobulin A-coated microorganisms or immune complexes containing immunoglobulin A.

Morbidity reduction employing a semi-standardized protocol

To evaluate a semi-standardized protocol for colostomy closure, the cases of 166 consecutive patients from 1974 through 1981 were analyzed retrospectively. There were 17 complications (17/166); overall morbidity rate was 2.4 per cent. A significantly increased incidence of major morbidity and septic complications was associated with colostomies closed at an interval of less than 8.5 weeks from formation (P≤0.001). Simple transverse closure of colostomy versus resection and end-to-end anastomosis did not result in increased morbidity (P≤0.1). The wound infection rate was 1.2 per cent (2/166) with 135/166 wounds closed primarily, or primarily over a subcutaneous drain, thus rendering primary wound closure safe and desirable

Anatomic location of penetrating lower-extremity trauma predicts compartment syndrome development

BACKGROUND Compartment syndrome of the lower extremity can be a difficult diagnosis to make with serious consequences if diagnosis and intervention is delayed. Identifying patients who are more likely to develop this syndrome can help prevent the associated complications. The purpose of this study was to evaluate whether the anatomic location of the penetrating lower-extremity injuries can predict development of compartment syndrome. METHODS A retrospective chart review was performed of all patients admitted for a minimum of 23 hours to the University of South Alabama trauma center for penetrating lower-extremity trauma during the 8-year period from July 1998 through June 2006. Patients were entered in the study if wound trajectory was confined to the lower extremity between the inguinal ligament and the ankle. Injuries were categorized as above knee (AK) or below knee (BK), and whether the injury was in the proximal or distal half of the extremity segment. Clinical examination or compartmental pressures were used to diagnose BK compartment syndrome. RESULTS A total of 321 patients sustained 393 lower-extremity injuries during the study period, of which 255 (65%) were AK and 138 (35%) were BK. Thirty-one (8%) lower extremities developed BK compartment syndrome with 29 (94%) secondary to penetrating injuries of the BK segment. All BK injuries that developed compartment syndrome were located in the proximal half of the BK segment. Eighteen (7%) AK injuries underwent BK 4-compartment fasciotomy, 16 (6%) of which were prophylactic after surgical intervention for AK vascular injury. Two patients (1%) developed postoperative BK compartment syndrome after superficial femoral vein ligation. All AK injuries that underwent fasciotomy sustained vascular injuries requiring surgical intervention. No BK compartment syndromes occurred in any patients with expectantly managed AK or distal BK injuries. CONCLUSIONS Injuries to the proximal half of the BK segment are the most common cause for the development of compartment syndrome from penetrating injuries of the lower extremity. Development of BK compartment syndrome because of penetrating AK injury is rare without an associated surgically significant vascular injury. Observational admission for compartment syndrome development in patients with penetrating injury to the AK segment or distal BK segment is unnecessary.

Increased Rural Vehicular Mortality Rates: Roadways with Higher Speed Limits or Excessive Vehicular Speed?

OBJECTIVE The purpose of this study was to assess whether higher roadway speed limits and excessive vehicular speed were contributing factors to increased rural vehicular mortality rates in the State of Alabama. METHODS During a 2-year period from January 2001 through December 2002, data were collected from Alabama police crash reports and EMS patient care reports. Police crash reports and EMS patient care reports were linked utilizing an imputational methodology. Vehicular speeds were estimated speeds extracted from police crash reports. Vehicular speeding was defined as estimated speeds greater than posted speed limits. RESULTS A total of 38,117 reports were linked. Of those, 30,260 (79%) and 7,857 (21%) were injured in rural and urban settings, respectively. The frequency of vehicular speeding was significantly higher in rural (18.8%) than in urban settings (9.4%) (p < 0.0001). At vehicular speeds less than 26 mph, mortality rates for occupants of speeding and nonspeeding vehicles were not significantly different in rural (1.68%, 0.82%) and urban (1.44%, 0.59%) settings (p = 0.78,1.0), respectively. On roads with posted speeds of 26 to 50 mph, mortality rates for occupants in speeding vehicles were not significantly different in rural (3.75%) and urban (2.23%) settings (p = 0.1360). For occupants of nonspeeding vehicles on roads with posted speeds of 26 to 50 mph, mortality rates were significantly greater in rural (0.72%) than in urban (0.35%) settings (p < 0.0032). On roads with posted speeds of 51 to 70 mph, mortality rates for occupants in speeding vehicles were not significantly different in rural (5.80%) and urban (4.95%) settings (p = 1.0). For occupants of nonspeeding vehicles on roads with posted speeds of 51 to 70 mph, mortality rates were significantly greater in rural (1.92%) than in urban (0.94%) settings (p = 0.01). CONCLUSIONS Vehicular speeding occurs with significantly higher frequency in rural settings. This imparts a greater overall vehicular mortality rate. At higher rates of speed, mortality rates for travel above the posted speed limit are similar in rural and urban settings; however, mortality rates for travel within the posted speed limit are greater in rural settings. This suggests factors beyond higher and excessive vehicular speed impart higher rates in rural settings.

Improving rural emergency medical service response time with global positioning system navigation

OBJECTIVE Rural emergency medical services (EMS) often serves expansive areas that many EMS personnel are unfamiliar with. EMS response time is increased in rural areas, which has been suggested as a contributing factor to increased mortality rates from motor vehicle crashes (MVCs) and nontraumatic emergencies. The purpose of this study was to assess the effect of a global positioning system (GPS) on rural EMS response time. METHODS GPS units were placed in ambulances of a rural EMS provider. The GPS units were set for fastest route (not shortest distance) to the scene that depends on traffic lights and posted road speed. During a 1-year period from September 2006 to August 2007, EMS response time and mileage to the scene were recorded for MVCs and other emergencies. Response times and mileage to the scene were then compared with data from the same EMS provider during a similar 1-year period when GPS technology was not used. EMS calls less than 1-mile were removed from both data sets because GPS was infrequently used for short travel distances. RESULTS During the 1-year period before utilization of GPS, 893 EMS calls greater than 1 mile were recorded and 791 calls recorded with GPS. The mean EMS response time for MVCs was 8.5 minutes without GPS and 7.6 minutes with GPS (p < 0.0001). When MVCs were matched for miles traveled, mean EMS response time without GPS was 13.7 minutes versus 9.9 minutes with GPS (p < 0.001). CONCLUSION GPS technology can significantly improve EMS response time to the scene of MVCs and nontraumatic emergencies.

Light microscopic morphometric analysis of rat ileal mucosa. I. Component quantitation of IgA-containing immunocytes.

A light microscopic morphometric analysis of IgA-containing immunocytes within samples of ileal mucosa was performed. The following groups of rats were studied:(1) animals raised in a gnotobiotic environment (microbial reduction); (2) animals with iatrogenic selffilling intestinal blind loops (microbial proliferation); and (3) control animals (sham operation). The unlabeled antibody enzyme immunohistochemical localization technique was employed for the identification of intracellular IgA. Component quantitation involved use of a micrometer component quantitator. Numerical density of the immunocyte population was determined by component quantitation of individual and total immunocyte volumes and by application of the Floderus equation. The methodology employed provided a precise quantitative analysis of all mucosal components of normal and manipulated rat ileum. A statistically significant reduction in the volume percentage of IgA-containing immunocytes in association with both microbial reduction and microbial proliferation was observed. The volume percentage reduction of the IgA-containing immunocyte population associated with gnotobiosis may reflect decreased microbial antigenic stimulation, whereas that associated with microbial proliferation may reflect the presence of an increased population of immunocytes producing non-IgA immunoglobulins.