Validating performance of TRISS, TARN and NORMIT survival prediction models in a Norwegian trauma population.

INTRODUCTION: Anatomic injury, physiological derangement, age, injury mechanism and pre-injury comorbidity are well-founded predictors of trauma outcome. Statistical prediction models may have poorer discrimination, calibration and accuracy when applied in new locations. We aimed to compare the TRISS, TARN and NORMIT survival prediction models in a Norwegian trauma population. METHODS: Consecutive patients admitted to Oslo University Hospital Ullevål within 24 h after injury, with Injury Severity Score ≥ 10, proximal penetrating injuries, or received by trauma team, were studied. Original NORMIT coefficients were updated in a derivation dataset (NORMIT 2; n = 5923; 2005-2009). TRISS, TARN and NORMIT prediction models were evaluated in the validation dataset (n = 6348; 2010-2013) using two different AIS editions for injury coding. Exclusion due to missing data was 0.26%. Outcome was 30-day mortality. Validation included AUROC, scaled Brier statistics, and calibration plots. RESULTS: The NORMIT models had significantly better discrimination, calibration, and overall fit than the TRISS 09, TARN 09 and TARN 12 models. The updated NORMIT 2 had higher numerical values of AUROC and scaled Brier than the original NORMIT, but with overlapping 95%CI. Overlapping 95%CI for AUROCs and Discrimination slopes indicated that the TARN and TRISS models performed similarly. Calibration plots showed tight and consistent predictions over all Ps strata for NORMIT 2 run on AIS'98 coded data, and only little deterioration when AIS'08 data was substituted. CONCLUSIONS: In a Norwegian trauma population, the updated Norwegian survival prediction model in trauma (NORMIT 2) performed better than well-established British and US alternatives. External validation of these three models in other Nordic populations is warranted.

Norwegian survival prediction model in trauma: modelling effects of anatomic injury, acute physiology, age, and co-morbidity.

INTRODUCTION: Anatomic injury, physiological derangement, age, and injury mechanism are well-founded predictors of trauma outcome. We aimed to develop and validate the first Scandinavian survival prediction model for trauma. METHODS: Eligible were patients admitted to Oslo University Hospital Ullevål within 24 h after injury with Injury Severity Score ≥ 10, proximal penetrating injuries or received by a trauma team. The derivation dataset comprised 5363 patients (August 2000 to July 2006); the validation dataset comprised 2517 patients (August 2006 to July 2008). Exclusion because of missing data was < 1%. Outcome was 30-day mortality. Logistic regression analysis incorporated fractional polynomial modelling and interaction effects. Model validation included a calibration plot, Hosmer-Lemeshow test and receiver operating characteristic (ROC) curves. RESULTS: The new survival prediction model included the anatomic New Injury Severity Score (NISS), Triage Revised Trauma Score (T-RTS, comprising Glascow Coma Scale score, respiratory rate, and systolic blood pressure), age, pre-injury co-morbidity scored according to the American Society of Anesthesiologists Physical Status Classification System (ASA-PS), and an interaction term. Fractional polynomial analysis supported treating NISS and T-RTS as linear functions and age as cubic. Model discrimination between survivors and non-survivors was excellent. Area (95% confidence interval) under the ROC curve was 0.966 (0.959-0.972) in the derivation and 0.946 (0.930-0.962) in the validation dataset. Overall, low mortality and skewed survival probability distribution invalidated model calibration using the Hosmer-Lemeshow test. CONCLUSIONS: The Norwegian survival prediction model in trauma (NORMIT) is a promising alternative to existing prediction models. External validation of the model in other trauma populations is warranted.

Physiologic, demographic and mechanistic factors predicting New Injury Severity Score (NISS) in motor vehicle accident victims.

BACKGROUND: Current literature on motor vehicle accidents (MVAs) has few reports regarding field factors that predict the degree of injury. Also, studies of mechanistic factors rarely consider concurrent predictive effects of on-scene patient physiology. The New Injury Severity Score (NISS) has previously been found to correlate with mortality, need for ICU admission, length of hospital stay, and functional recovery after trauma. To potentially increase future precision of trauma triage, we assessed how the NISS is associated with physiologic, demographic and mechanistic variables from the accident site. METHODS: Using mixed-model linear regression analyses, we explored the association between NISS and pre-hospital Glasgow Coma Scale (GCS) score, Revised Trauma Score (RTS) categories of respiratory rate (RR) and systolic blood pressure (SBP), gender, age, subject position in the vehicle, seatbelt use, airbag deployment, and the estimated squared change in vehicle velocity on impact ((Δv)(2)). Missing values were handled with multiple imputation. RESULTS: We included 190 accidents with 353 dead or injured subjects (mean NISS 17, median NISS 8, IQR 1-27). For the 307 subjects in front-impact MVAs, the mean increase in NISS was -2.58 per GCS point, -2.52 per RR category level, -2.77 per SBP category level, -1.08 for male gender, 0.18 per year of age, 4.98 for driver vs. rear passengers, 4.83 for no seatbelt use, 13.52 for indeterminable seatbelt use, 5.07 for no airbag deployment, and 0.0003 per (km/h)(2) velocity change (all p<0.002). CONCLUSION: This study in victims of MVAs demonstrated that injury severity (NISS) was concurrently and independently predicted by poor pre-hospital physiologic status, increasing age and female gender, and several mechanistic measures of localised and generalised trauma energy. Our findings underscore the need for precise information from the site of trauma, to reduce undertriage, target diagnostic efforts, and anticipate need for high-level care and rehabilitative resources.

Proposal of a CT scoring system of the paranasal sinuses in diagnosing cystic fibrosis.

The purpose of this study was to develop a paranasal sinus CT scoring system that could be used as a diagnostic tool to discriminate cystic fibrosis (CF) patients from control patients examined for sinonasal disease. The model should include as few and easily applicable criteria as possible, supported by statistical analyses and clinical judgement. We used data from 116 CF and 136 control patients. The CF patients were grouped according to the number of confirmed CF mutations: genetically verified (CF-2), or based on sweat testing and clinical findings alone (CF-1, CF-0). Nine paranasal sinus CT criteria, including development, pneumatisation variants and inflammatory patterns, were evaluated. The final model included three criteria: (a) frontal and (b) sphenoid sinus development, and (c) absence of three pneumatisation variants. This model discriminated CF-2 from controls with overlap of summed scores in only 8 of 206 patients. When this model was applied in the CF-1 and CF-0 groups, two populations seemed to exist. A larger group with summed scores overlapping that of the CF-2 group and a smaller group with summed scores overlapping that of the control group. We conclude that this CT scoring system may support, as well as exclude, a CF diagnosis in cases of diagnostic uncertainty.

CT characterization of inflammatory paranasal sinus disease in cystic fibrosis.

PURPOSE: In patients with cystic fibrosis (CF) the prevalence of paranasal sinus affection approaches 100%. We hypothesized that the hyperviscous mucus reducing mucociliary clearance in CF patients could give sinonasal inflammatory patterns different from those in non-CF patients. We wanted to compare the extent and distribution of paranasal sinus disease and the inflammatory patterns in these two groups of patients. MATERIAL AND METHODS: One-hundred-and-eight CF patients (3-54 years old) and 79 controls (7-51 years old) with paranasal sinus disease confirmed at coronal CT were compared. The extent of disease was noted for each sinus and summed for all sinuses. Inflammatory patterns were identified and classified into: 1) routine surgery group (sporadic, infundibular and ostiomeatal complex (OMC) patterns) and 2) complex surgery group (sinonasal polyposis and sphenoethmoid recess (SER) patterns). RESULTS: CF patients had more widespread sinonasal inflammatory changes and more advanced disease for each sinus. Most CF patients displayed sinonasal polyposis and SER patterns while most controls displayed sporadic, infundibular or OMC patterns. As a result, 67% of CF patients were classified to the complex surgery group, compared to only 19% of controls. CONCLUSION: The impaired mucociliary clearance in CF causes widespread inflammatory paranasal sinus disease, with inflammatory patterns more often requiring extensive surgery, with a higher risk of cerebrospinal fluid leak or bleeding, or involving areas that are more difficult to reach with the endoscope.

CT characterization of developmental variations of the paranasal sinuses in cystic fibrosis.

PURPOSE: To describe variations of paranasal sinus development in patients with cystic fibrosis (CF) and in non-CF patients examined for inflammatory sinonasal disease. We focused on anatomic variants that predispose to orbital and cerebral penetration during functional endoscopic sinus surgery (FESS), e.g. hypoplasia of the maxillary sinus and low ethmoid roof. MATERIAL AND METHODS: One hundred and sixteen CF patients (3-54 years, median 18) and 136 control patients (7-51 years, median 31) were examined with coronal CT of the paranasal sinuses. CF patients were grouped according to number of confirmed mutations: CF-2 (n=70), CF-1 (n=32), CF-0 (n=14). CT images were evaluated with respect to paranasal sinus development, pneumatization variants and bony variants. RESULTS: Frontal sinus aplasia and maxillary, ethmoid, and sphenoid sinus hypoplasia were markedly more frequent in CF-2 than in control patients. No CF-2 patient had pneumatization variants such as Haller cells or concha bullosa. Low ethmoid roof was seen in 30% of CF-2 children, but in no control children. CF-1 and CF-0 groups had prevalences of aplasia and hypoplasia intermediate to that of CF-2 and control patients. CONCLUSION: Genetically verified CF patients had less developed sinuses, lacked pneumatization variants, and more often had anatomic variants that predispose to complications during FESS. Normally developed sinuses and pneumatization variants in some genetically unverified CF patients (CF-1, CF-0) suggest that these patients may be erroneously diagnosed.

Heart rate response to transient chemoreceptor stimulation in term infants is modified by exposure to maternal smoking.

Modulation of heart rate (HR) during transient hyperoxia, hypoxia, and hypercapnia was studied in 46 healthy term infants on 103 occasions (postnatal d 2 to 82). Twenty-three infants had smoking mothers (median, 11 cigarettes/d). Transient chemoreceptor stimuli (100% O(2), 15% O(2), or 3% CO(2)) were presented repeatedly during quiet sleep. Beat-by-beat HR and breath-by-breath ventilation were recorded continuously. The coherently averaged HR and ventilation responses to each stimulus were calculated for each infant at each age. Outcome variables (HR change from baseline to end of stimulation, maximum HR change, and time to half-maximum) were analyzed by ANOVA. Overall, HR declined during hyperoxia (median change, 4.2 beats/min) and rose during hypoxia (median change, 4.2 beats/min) and hypercapnia (median change, 4.6 beats/min). The percentage change in HR was positively correlated with the percentage change in ventilation (p < 0.001). Increasing number of cigarettes smoked by the mother was correlated with deeper HR declines and smaller HR rises (p = 0.02). For the population as a whole, the HR response lagged 3.8 s behind the ventilatory response during hyperoxia and hypoxia (p < 0.001), whereas during hypercapnia there was no significant lag. The lag in HR response in the smoke-exposed group was 2.5 s greater than that in the control group for all three stimuli (p = 0.001), and the difference increased with the number of cigarettes smoked by the mother (p < 0.01). Both pulmonary reflexes and the type of the chemoreceptor stimulus seemed to influence HR. Maternal smoking affected the magnitude and time-course of the HR response in a dose-dependent manner.

Complementary role of MR imaging of ethmomaxillary sinus disease depicted at CT in cystic fibrosis.

PURPOSE: To assess whether MR imaging can improve characterization of ethmomaxillary opacification diagnosed at CT in patients with cystic fibrosis (CF) in order to select patients that may benefit from functional endoscopic sinus surgery (FESS). MATERIAL AND METHODS: Sixty-two CF patients (26 females and 36 males) aged 4-50 years (median 20 years) with ethmomaxillary sinus disease at CT underwent MR examination of the paranasal sinuses (coronal T1 and STIR sequences). FESS had been performed in 28 of the patients prior to this study. MR signal intensities were interpreted as mucosal thickening or infectious material, according to a previous study. RESULTS: Three major maxillary sinus MR patterns could be distinguished: Air-filled, oval-shaped pus-filled, and streaky-shaped pus-filled sinus lumen. For air-filled maxillary sinuses with mucosal thickening, CT and MR imaging were diagnostically equivalent. Where CT showed homogeneous opacification of the maxillary sinuses, MR imaging differentiated between thickened mucosa and pus-filled areas. Patients who had undergone FESS most commonly had air-filled or streaky-shaped pus-filled maxillary sinus lumen. In non-operated patients oval-shaped pus-filled sinus lumen was most common and could occur without ethmoid disease. CONCLUSION: MR imaging of the paranasal sinuses can differentiate between infectious material and thickened mucosa and should be used to select CF patients with pus-filled areas that can be eradicated with FESS.

A method of assessing ventilatory responses to chemoreceptor stimulation in infants.

Various methods of assessing infant chemoreceptor responses have been reported in the literature. However, equipment dead space, trigeminal stimulation and inherent respiratory variability may have affected the results. A method is presented which attempts to reduce the effect of these factors and thereby isolate the chemoreceptor response. Inspiratory gas was delivered into a lightweight face mask with a pliable rim, minimal dead space and a connected pneumotachograph. Ventilatory data were computed breath by breath. Computer-controlled electromagnetic valves allowed instantaneous switching between air and different gas mixtures, repeated in a randomized sequence. In 18 healthy term neonates, the mask increased ventilation by 12% (95% confidence interval 6-18%), measured by calibrated strain-gauge bands. The effect on respiratory frequency and tidal volume differed significantly between sleep states. Neonates were challenged with short-lasting hyperoxia, mild hypoxia, rebreathing and mild hypercapnia. Coherent averaging of several ventilatory responses from each sleep state reduced the variability while maintaining a high time-resolution.

Development of oxygen sensitivity in infants of smoking and non-smoking mothers.

AIMS: To assess the effect of prenatal cigarette smoke exposure on the postnatal resetting of oxygen sensitivity in term infants. METHODS: 15 healthy term infants of smoking mothers (median 10 cigarettes/day) and 16 controls were studied during quiet sleep 1, 3, and 10 days and 10 weeks postnatally. Strain-gauge respiratory trace was continuously recorded. Repeated 15-s challenges with 100% O2 and 15% O2 were presented in randomised order through a face mask. A median of six hyperoxic and six hypoxic challenges per recording were obtained. Breath-by-breath ventilation in a time-window from 20 s before onset of stimulus to 60 s after was extracted. For each infant at each age, the normalised coherently averaged response to hyperoxia and hypoxia was calculated. Mean ventilation at end of the 15-s stimulus was analysed with ANOVA, as were parameters describing a function fitted to each averaged response. RESULTS: During air breathing, smoke-exposed infants had higher respiratory rates and lower tidal volumes than controls. Nicotine concentration in infant hair, measured by gas chromatography, was positively correlated with maternal level of smoking. A long-term development in oxygen sensitivity was demonstrated in both groups. However, neither the time-course nor the magnitude of O2 responses was affected by maternal smoking. Overall, hyperoxia reduced ventilation by 6.3% at day 1, 13.2% at day 3, 29.6% at day 10, and 40.0% at week 10. Transient hypoxia increased ventilation by 3.5%, 3.2%, 6.4%, and 8.8%, respectively, at the four ages studied.