Penn State equation versus indirect calorimetry for nutritional assessment in patients with traumatic brain injury.

BACKGROUND: Nutritional assessment can be challenging in patients with traumatic brain injury (TBI), and indirect calorimetry may be a more suitable method than predictive equations. We compared the Penn State equation versus the gold standard of indirect calorimetry for the nutritional assessment of patients with TBI, and quantified the difference between nutritional requirements and actual patient intake. METHODS: This single-centre, prospective cohort study included patients with moderate (Glasgow Coma Scale score 9-12) and severe (Glasgow Coma Scale score 3-8) TBI admitted to the Montreal General Hospital intensive care unit (ICU) between June 2018 and March 2019. Penn State equation estimates and indirect calorimetry measurements were collected, and actual intake was drawn from medical records. We compared the 2 assessment methods using a Spearman correlation coefficient. RESULTS: Twenty-three patients with TBI (moderate in 7 and severe in 16) were included in the study. Overall, there was a moderate positive correlation between the Penn State equation estimate and indirect calorimetry readings (correlation coefficient 0.457, p = 0.03); however, the correlation was weaker in severe TBI (correlation coefficient 0.174, p = 0.5) than in moderate TBI (correlation coefficient 0.929, p = 0.003). When compared to indirect calorimetry assessment, patients received 5.4% (p = 0.5) of required intake on the first day and 43.9% (p = 0.8) of required daily intake throughout their ICU stay. CONCLUSION: Patients with moderate or severe TBI in the ICU received less than 50% of their nutritional requirements. The difference between the Penn State equation and indirect calorimetry assessments was most noticeable for patients with severe TBI, which indicates that indirect calorimetry may be a more suitable tool for assessment of nutritional needs in this population.

Content analysis of bowel protocols for the management of constipation in adult critically ill patients.

PURPOSE: Alterations in bowel habits are common during critical illness, and bowel protocols are gaining acceptance. Our objective was to characterize bowel protocols in a cross-sectional analysis of ICUs. MATERIALS AND METHODS: We engaged 44 adult ICUs and performed content analysis of bowel protocols, addressing initiation criteria, medications incorporated, medication escalation, discontinuation criteria, stool assessment methods, and protocol contraindications. RESULTS: Bowel protocols operated in 33/44 ICUs (79.5%). The commonest medications were senna (81.0%) and bisacodyl (75.6%). Less common agents were sodium phosphate (45.9%), glycerin (43.2%), docusate sodium (43.2%), polyethylene glycol 3350 (37.8%), lactulose (29.7%), sodium citrate (16.2%), milk of magnesia (13.5%) and mineral oil (16.2%). Bowel protocols were activated by nurses (62.8%) based on initiation criteria [no bowel movement for 24-96 h (35.1%), opioid use (18.9%), "at risk for constipation" (13.5%), stool on digital rectal exam (10.8%), feeding initiation (10.8%), and ICU admission (8.1%)]. Laxative escalation criteria included time from last bowel movement (59.4%), opioid use (18.9%) and no stool on digital rectal exam (10.8%), while 15 (40.5%) included diarrhea as a discontinuation criterion. CONCLUSIONS: Bowel protocols have variable initiation, escalation, and discontinuation criteria incorporating different classes of laxatives, reflecting unclear evidence about optimal bowel management strategies in ICU.

The effect of heparan sulfate application on bone formation during distraction osteogenesis.

Bone morphogenetic proteins (BMPs) are recognized for their ability to induce bone formation in vivo and in vitro. Their osteogenic and osteoinductive properties are tightly regulated by the secretion of specific BMP antagonists, which have been shown to physically bind and sometimes be blocked by the extracellular proteoglycan heparan sulphate side chains (from hereon referred to as HS). The purpose of this study was to investigate if local application of 5 µg of HS proteoglycan to a bone regenerate site in a mouse model of distraction osteogenesis (DO) can accelerate bone healing and affect the expression of key members of the BMP signaling pathway. DO was performed on the right tibia of 115 adult male wild-type mice. At mid-distraction (day 11), half the group was injected locally with 5 µg of HS, while the other half was injected with saline. The mice were sacrificed at 2 time-points: mid-consolidation (34 days) and full consolidation (51 days). The distracted tibial zone was then collected for analysis by µCT, radiology, biomechanical testing, immunohistochemistry, and histology. While µCT data showed no statistically significant difference in bone formation, the results of biomechanical testing in stiffness and ultimate force were significantly lower in the HS-injected bones at 51 days, compared to controls. Immunohistochemistry results also suggested a decrease in expression of several key members of the BMP signaling pathway at 34 days. Furthermore, wound dehiscence and infection rates were significantly elevated in the HS group compared to the controls, which resulted in a higher rate of euthanasia in the treatment group. Our findings demonstrate that exogenous application of 5 µg of HS in the distracted gap of a murine model had a negative impact on bone and wound healing.

Physiological referrals for paediatric musculoskeletal complaints: A costly problem that needs to be addressed.

BACKGROUND/OBJECTIVE: Referrals to paediatric orthopedists for physiologically normal conditions consume limited resources and delay care for patients. The goal of the present study was to formally define such referrals and determine their prevalence. METHODS: A retrospective review evaluated consecutive referrals to a single tertiary paediatric orthopedic centre over two eight-month periods. Referrals from family physicians and paediatricians were retained for analysis. Physiological referrals were defined as a final orthopedic diagnosis of 'within physiological norms'; and no scheduled follow up. RESULTS: Physiological conditions represented 22.5% of referrals. The type of referring physician did not determine referral quality. Flat foot, intoeing and genu varum/valgum exhibited physiological referral rates that exceeded 40%. CONCLUSION: Physiological referrals constitute a large portion of the outpatient paediatric orthopedic practice and represent a substantial unnecessary cost to the Canadian medical system. Future strategies to improve referral quality should target undergraduate and postgraduate musculoskeletal education.

HISTORIQUE ET OBJECTIF: Les aiguillages vers des orthopédistes pédiatres en raison de problèmes physiologiquement normaux drainent des ressources limitées et retardent les soins aux patients. La présente étude visait à définir officiellement ces aiguillages et à en déterminer la prévalence. MÉTHODOLOGIE: Les chercheurs ont procédé à une analyse rétrospective d'aiguillages consécutifs dans un seul centre de soins tertiaires en orthopédie pédiatrique sur deux périodes de huit mois. Ils ont conservé les aiguillages des médecins de famille et des pédiatres en vue de les analyser. Ils ont défini les aiguillages physiologiques comme un diagnostic orthopédique final de « dans la norme physiologique ¼, sans rendez-vous de suivi. RÉSULTATS: Les problèmes physiologiques représentaient 22,5 % des aiguillages. Le type de médecin traitant ne déterminait pas la qualité de l'aiguillage. Les aiguillages pour les pieds plats, l'endogyrisme, les jambes arquées ou les genoux cagneux représentaient plus de 40 % des aiguillages physiologiques. CONCLUSION: Les aiguillages physiologiques constituent une forte proportion des consultations externes en orthopédie pédiatrique et représentent des coûts inutiles importants pour le système médical canadien. Les futures stratégies pour améliorer la qualité des aiguillages devraient cibler la formation musculosquelettique au premier cycle et aux cycles supérieurs.

Are endogenous BMPs necessary for bone healing during distraction osteogenesis?

Previous reports suggest the application of exogenous BMPs can accelerate bone formation during distraction osteogenesis (DO). However, there are drawbacks associated with the use of exogenous BMPs. A possible alternative to the use of exogenous BMPs is to upregulate the expression of endogenous BMPs. Since DO results in spontaneously generated de novo bone formation in a uniform radiographic, histological, and biomechanical temporal sequence, a genetically engineered model lacking endogenous BMP2 should have measurable deficits in bone formation at different time points. We performed DO on BMP2(fl/+) and BMP2(fl/+ cre) mice using a miniature Ilizarov fixator. Distracted samples were collected at various time points and analyzed using real time-quantitative PCR, lCT, radiology, immunohistochemistry, histology, and biomechanical testing. Immunohistochemical studies of 34-day heterozygous samples showed reduced expression of BMP2, BMP7, BMPR1a, ACTR1, and ACTR2b. lCT analysis of 51-day heterozygous samples revealed a decrease in trabecular number and increase in trabecular separation. Biomechanical testing of 51-day heterozygous samples revealed decreased stiffness and increased ultimate displacement. Radiological analysis showed the heterozygotes contained a decreased bone fill score at 17, 34, and 51 days. These data suggest endogenous BMPs are important for bone healing and manipulating endogenous BMPs may help accelerate bone consolidation during DO.

Characterizing the BMP pathway in a wild type mouse model of distraction osteogenesis.

Distraction osteogenesis (DO) is a well established surgical technique for limb lengthening and replacement of bone loss due to trauma, infection or malignancies. Although the technique is widely used, one of its limitations is the long period of time required for the newly formed bone to consolidate. We have previously shown that exogenous application of bone morphogenetic proteins (BMPs) can increase bone formation during DO, however, exogenous BMPs have many drawbacks. An alternative method for accelerating the rate of bone formation may be to modulate the intrinsic BMP signaling pathway. The aim of the current study was to analyze the expression of various genes involved in the BMP pathway at various time periods during DO in order to identify potential targets for therapeutic manipulation. DO was applied to the right tibia of 80 adult wild type mice. Distraction began after a latency period of 5 days at a rate of 0.2 mm/12 h for 2 weeks. Mice were sacrificed in groups of 12 at the following times post surgery: day 5 (latency), days 11 and 17 (distraction) and days 34 and 51 (consolidation). Specimens were examined using radiology, microCT, histology, RT(2)PCR, immunohistochemistry and Western analysis. Genes involved in the BMP pathway including the BMP ligands, receptors, antagonists and downstream effectors were examined. A significant upregulation of BMPs 2, 4 and 6 was observed using both PCR and immunohistochemistry during the distraction phase. The expression of BMP7 remained constant throughout the distraction and consolidation process. Surprisingly, the only receptors which were upregulated significantly were the Activin Receptor Type 1 (ActR1) during distraction and Activin Receptor Type 2b (ActR2b) during consolidation. Most interestingly, simultaneously with the ligands, an increase in the expression of the antagonists, Noggin, Chordin, Inhibin and BMP3 was observed. This study provides a clearer understanding of expression patterns during DO, which is a valuable resource for finding therapeutic options to stimulate bone formation. The results suggest that blocking BMP inhibitors may be a possible method for increasing the function of intrinsic growth factors involved in bone regeneration.