A method for identifying the learning curve for the surgical stabilization of rib fractures.

BACKGROUND: Surgical stabilization of rib fractures (SSRF) is an accepted efficacious treatment modality for patients with severe chest wall injuries. Despite increased adoption of SSRF, surgical learning curves are unknown. We hypothesized intraoperative duration could define individual SSRF learning curves. METHODS: Consecutive SSRF operations between January 2017 and December 2021 at a single institution were reviewed. Operative time, as measured from incision until skin closure, was evaluated by cumulative sum methodology using a range of acceptable "missteps" to determine the learning curves. Misstep was defined by extrapolation of accumulated operative time data. RESULTS: Eighty-three patients underwent SSRF by three surgeons during this retrospective review. Average operative times ranged from 135 minutes for two plates to 247 minutes for seven plates. Using polynomial regression of average operative times, 75 minutes for general procedural requirements plus 35 minutes per plate were derived as the anticipated operative times per procedure. Cumulative sum analyses using 5%, 10%, 15%, and 20% incident rates for not meeting expected operative times, or "missteps" were used. An institutional learning curve between 15 and 55 SSRF operations was identified assuming a 90% performance rate. An individual learning curve of 15 to 20 operations assuming a 90% performance rate was observed. After this period, operative times stabilized or decreased for surgeons A, B, and C. CONCLUSION: The institutional and individual surgeon learning curves for SSRF appears to steadily improve after 15 to 20 operations using operative time as a surrogate for performance. The implementation of SSRF programs by trauma/acute care surgeons is feasible with an attainable learning curve. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

The Association Between Pulmonary Contusion Severity and Respiratory Failure.

BACKGROUND: Pulmonary contusions (PCs) have historically been viewed as a serious complicating factor in thoracic injury. Recently, there has been conflicting evidence regarding the influence of PCs on outcomes; however, many studies do not stratify contusions by severity and may miss clinical associations. We sought to identify if contusion severity is associated with worse outcomes. METHODS: A previously published chest wall injury database at an urban Level I trauma center was retrospectively reviewed. All severely injured subjects (defined as Injury Severity Score [ISS] ≥ 15) with moderate to severe thoracic injury (defined as a chest wall Abbreviated Injury Scale [AIS] ≥ 3) who required mechanical ventilation for > 24 h were stratified by contusion severity. Moderate to severe contusions were defined as AIS contusion ≥ 3 and Blunt Pulmonary Contusion 18 (BPC18) score ≥ 3. RESULTS: Over 5 y, 3,836 patients presented with chest wall injuries, of which 1,176 (30.6%) had concomitant contusions. When screened for inclusion criteria, 339 subjects with contusions and 211 subjects without contusions (no-PC) were identified. Of these, 234 had moderate to severe contusions defined by AIS contusion ≥ 3 (PC-A) and 230 had moderate to severe contusions by BPC18 ≥ 3 (PC-B). Compared to no-PC, both PC-A and PC-B groups had significantly lower mortality (17.9% and 17.4%, respectively, vs 28.9%); however, PC-A and PC-B groups had longer durations of mechanical ventilation (6 and 7 d, respectively, vs 5 d), longer ICU length of stay (10 and 10 vs 8 d), and longer overall hospital length of stay (15 and 15 vs 13 d). CONCLUSIONS: In severely injured polytrauma patients, PCs are seen with more severe chest injuries. Furthermore, moderate to severe contusions are associated with longer durations of mechanical ventilation, ICU length of stay, and hospital length of stay. Despite practice pattern changes, contusions appear to contribute significantly to the clinical course of the blunt chest wall injured patients.

Safety and efficacy of brain injury guidelines at a Level III trauma center.

BACKGROUND: Patients with mild to moderate traumatic brain injury (TBI) are often primarily managed by emergency medicine and trauma/acute care physicians. The Brain Injury Guidelines (BIG) were developed at an American College of Surgeons-accredited Level 1 trauma center to triage mild to moderate TBI patients and help identify patients who warrant neurosurgical consultation. The BIG have not been validated at a Level III trauma center. We hypothesized that BIG criteria can be safely adapted to an American College of Surgeons-accredited Level III trauma center to guide transfers to a higher echelon of care. METHODS: We reviewed the trauma registry at a Level III trauma center to identify TBI patients who presented with an Abbreviated Injury Severity-Head score greater than zero. Demographic data, injury details, and clinical outcomes were abstracted with primary outcome measures of worsening on second computed tomography of the head, neurosurgical intervention, transfer to a Level I trauma center, and in-hospital mortality. Patients were classified using the BIG criteria. After validating the BIG in our cohort, we reclassified patients using updated BIG criteria. Updated criteria included mechanism of injury, reclassification of anticoagulation or antiplatelet use, and replacement of the neurologic examination component with stratification by admission Glasgow Coma Scale (GCS) score. RESULTS: From July 2013 to June 2016, 332 TBI patients were identified: 115 BIG-1, 25 BIG-2, and 192 BIG-3. Patients requiring neurosurgical intervention (n = 30) or who died (n = 29) were BIG-3 with one exception. Patients with GCS score of less than 12 had worse outcomes than those with a GCS score of 12 or greater, regardless of BIG classification. Anticoagulant or antiplatelet use was not associated with worsened outcomes in patients not meeting other BIG-3 criteria. The updated BIG resulted in more patients in BIG-1 (n = 109) and BIG-2 (n = 100) without negatively affecting outcomes. CONCLUSION: The BIG can be applied in the Level III trauma center setting. Updated BIG criteria can aid triage of mild to moderate TBI patients to a Level I trauma center and may reduce secondary overtriage. LEVEL OF EVIDENCE: Care management, level IV.

The differential susceptibility of spores from virulent and attenuated Bacillus anthracis strains to aldehyde- and hypochlorite-based disinfectants.

This study compared the sensitivity of spores from virulent and attenuated Bacillus anthracis strains in suspension to inactivation by various chemical disinfectants. Spore suspensions from two virulent strains (A0256 and A0372) and two attenuated strains (Sterne and A0141) of B. anthracis were tested against two aldehyde-based disinfectants and one hypochlorite-based disinfectant. A novel statistical model was used to estimate 4-log(10) reduction times for each disinfectant/strain combination. Reduction times were compared statistically using approximate Z and χ(2) tests. Although there was no consistent correlation between virulence and increased sporicidal resistance across all three disinfectants, spores from the two virulent and two attenuated strains did display significantly different susceptibilities to different disinfectants. Significant disinfectant-strain interactions were observed for two of the three disinfectants evaluated. The comparative results suggest that the use of surrogate organisms to model the inactivation kinetics of virulent B. anthracis spores may be misleading. The accuracy of such extrapolations is disinfectant dependent and must be used with caution.

Implantation of the ossified cochlea: management with the split electrode array.

OBJECTIVES/HYPOTHESIS: To describe indications for, the surgical technique required, and the expected functional results of split electrode array cochlear implants. STUDY DESIGN: Retrospective chart review. METHODS: Data collected included etiology of deafness, radiographic findings, pre- and postoperative aided pure tone thresholds, and speech perception testing. Adult speech perception outcomes were measured using the Consonant Nucleus Consonant (CNC) monosyllable words and Hearing in Noise Test (HINT) in quiet/noise (+10 dB). The children were assessed using the Infants and Toddlers Meaningful Auditory Integration Scale. RESULTS: Five patients were implanted with a split electrode array. This included two adults and three children. Both adults had preoperative binaural aided pure tone averages worse than 50 dB and scores of 0% on both HINT quiet and CNC words. The children had undetectable preoperative aided thresholds and scored an average 4/40 on the IT-MAIS. Postimplant, the average threshold gain was 38.5 dB in the adults and 81.5 dB in the children. One adult improved to score 51%/22% on HINT quiet/noise at 6 months and 72%/30% at 12 months. The other adult continued to score 0% on HINT at 12 months but claimed substantial subjective auditory improvement after the first year of device use. The children averaged 28/40 on the IT MAIS at 6 months after implantation. Forty-two of 48 implanted electrodes were functional. CONCLUSIONS: The split electrode array is a useful alternative to traditional cochlear implants in treating deafened patients with cochlear ossification. Patients implanted with the split array show marked improvement in sound and speech perception.

Activity and preliminary characterization of Branchiostoma lanceolatum agglutinin.

The physical and chemical properties of a hemagglutinin from whole-body homogenates of the cephalochordate, Branchiostoma lanceolatum, are described. The hemagglutinin is proteinaceous since it is precipitated by trichloroacetic acid and ammonium sulphate, and all activity is lost at 60 degrees C or by treating with proteases. Carbohydrate moieties are probably also present since activity is lost after incubation with sodium metaperiodate. Activity is stable over pH 6-10. The agglutinin does not require Ca++ or Mg++, and a reduced titer after treatment with 2-mercaptoethanol and urea suggests the presence of both disulphide bonds and noncovalent linkages. Haemagglutination inhibition experiments with 17 saccharides and glycoproteins failed to show clear-cut carbohydrate specificity, with only mucin and fetuin having any inhibitory effect, so that the binding may be complex. Finally, cross-adsorption experiments suggest that only one lectin is present. The function of this lectin, especially in an immunobiological context, remains speculative.

The evolution of blood cells: facts and enigmas.

Although the origin and evolution of vertebrate blood cells is conjectural and controversial, it is, nevertheless, of great interest, particularly to comparative immunologists seeking an underlying trend in the phylogenetic development of immunity. This review examines possible relationships between invertebrate and vertebrate blood cells and describes some of the original concepts put forward to account for blood cell evolution.

Activity and preliminary characterisation of a hemagglutinin from the hemichordate Saccoglossus ruber.

Examination of whole body homogenates of the hemichordate, Saccoglossus ruber, has revealed the presence of a hemagglutinin with specificity for carbohydrates containing a D-galactose configuration. An analysis of the chemical and physical properties of the agglutinin showed it to be a non-dialysable, heat-labile protein, susceptible to the action of pronase E, but resistant to trypsin. Oxidation by periodate had no effect on agglutination and activity was not dependent upon the divalent cations, Ca2+ or Mg2+. The agglutinin was associated with the proboscis, collar and trunk regions, and was also detected in mucus covering the body surface. A possible role for the agglutinin in the defence system of the animal is discussed.

A step-wedge standard for the quantification of immunoperoxidase techniques.

This report describes the preparation and use of an artificial tissue containing differing amounts of an antigen covalently bound to gelatine (step wedge). The use of this step wedge enables the variables in the immunoperoxidase technique to be studied separately. The step wedge may be used as a standard in immunocytochemical quantification. By performing all the steps of the immunoperoxidase procedure on the step-wedge section and the tissue section simultaneously, valid comparisons can be made regarding changes in the amount of antigen in tissues. Absolute measurements of amounts of antigen in tissue cannot be made with this technique at present because of the loss of antigenicity involved in the preparation of the step wedge, differences of penetration by reagents between step wedge and tissue, and non-uniform distribution of antigens in this tissue. Use of the step wedge has shown that, under some circumstances, an increase in amount of antigen may be associated with a reduction in the amount of reaction product, demonstrating the impossibility of making any deductions about variations in the amount of antigens without control of the technique employed by a method such as the one presented here.

Inhibition of the mixed lymphocyte reaction by fractionated niridazole urine dialysate.

Urine dialysate from rats treated orally with 25 mg/Kg 3H-labeled niridazole was fractionated by DEAE-Sepharose column chromatography and was found to contain three radioactive metabolites and no parent compound. When human niridazole urine dialysate (NUD) was fractionated under identical conditions, fractions corresponding to the three rat NUD metabolites were found to inhibit the human one-way MLR. No inhibition was obtained with fractionated control urine dialysate. It was concluded that nonimmunosuppressive niridazole is metabolized by rats and man to produce three active compounds with the ability to suppress the in vitro response to alloantigens.