Sepsis in mechanically ventilated patients with spinal cord injury: a retrospective analysis

Early Prognostication of Critical Patients With Spinal Cord Injury: A Machine Learning Study With 1485 Cases

STUDY DESIGN

A retrospective case-series.

OBJECTIVE

The study aims to use machine learning to predict the discharge destination of spinal cord injury (SCI) patients in the intensive care unit.

SUMMARY OF BACKGROUND DATA

Prognostication following SCI is vital, especially for critical patients who need intensive care.

PATIENTS AND METHODS

Clinical data of patients diagnosed with SCI were extracted from a publicly available intensive care unit database. The first recorded data of the included patients were used to develop a total of 98 machine learning classifiers, seeking to predict discharge destination (eg, death, further medical care, home, etc.). The microaverage area under the curve (AUC) was the main indicator to assess discrimination. The best average-AUC classifier and the best death-sensitivity classifier were integrated into an ensemble classifier. The discrimination of the ensemble classifier was compared with top death-sensitivity classifiers and top average-AUC classifiers. In addition, prediction consistency and clinical utility were also assessed.

RESULTS

A total of 1485 SCI patients were included. The ensemble classifier had a microaverage AUC of 0.851, which was only slightly inferior to the best average-AUC classifier ( P =0.10). The best average-AUC classifier death sensitivity was much lower than that of the ensemble classifier. The ensemble classifier had a death sensitivity of 0.452, which was inferior to the top 8 death-sensitivity classifiers, whose microaverage AUC were inferior to the ensemble classifier ( P <0.05). In addition, the ensemble classifier demonstrated a comparable Brier score and superior net benefit in the DCA when compared with the performance of the origin classifiers.

CONCLUSIONS

The ensemble classifier shows an overall superior performance in predicting discharge destination, considering discrimination ability, prediction consistency, and clinical utility. This classifier system may aid in the clinical management of critical SCI patients in the early phase following injury.

LEVEL OF EVIDENCE

Level 3.

Spinal cord injury-induced neurogenic bowel: A role for host-microbiome interactions in bowel pain and dysfunction

Background and aims

Spinal cord injury (SCI) affects roughly 300,000 Americans with 17,000 new cases added annually. In addition to paralysis, 60% of people with SCI develop neurogenic bowel (NB), a syndrome characterized by slow colonic transit, constipation, and chronic abdominal pain. The knowledge gap surrounding NB mechanisms after SCI means that interventions are primarily symptom-focused and largely ineffective. The goal of the present studies was to identify mechanism(s) that initiate and maintain NB after SCI as a critical first step in the development of evidence-based, novel therapeutic treatment options.

Methods

Following spinal contusion injury at T9, we observed alterations in bowel structure and function reflecting key clinical features of NB. We then leveraged tissue-specific whole transcriptome analyses (RNAseq) and fecal 16S rRNA amplicon sequencing in combination with histological, molecular, and functional (Ca2+ imaging) approaches to identify potential mechanism(s) underlying the generation of the NB phenotype.

Results

In agreement with prior reports focused on SCI-induced changes in the skin, we observed a rapid and persistent increase in expression of calcitonin gene-related peptide (CGRP) expression in the colon. This is suggestive of a neurogenic inflammation-like process engaged by antidromic activity of below-level primary afferents following SCI. CGRP has been shown to disrupt colon homeostasis and negatively affect peristalsis and colon function. As predicted, contusion SCI resulted in increased colonic transit time, expansion of lymphatic nodules, colonic structural and genomic damage, and disruption of the inner, sterile intestinal mucus layer corresponding to increased CGRP expression in the colon. Gut microbiome colonization significantly shifted over 28 days leading to the increase in Anaeroplasma, a pathogenic, gram-negative microbe. Moreover, colon specific vagal afferents and enteric neurons were hyperresponsive after SCI to different agonists including fecal supernatants.

Conclusions

Our data suggest that SCI results in overexpression of colonic CGRP which could alter colon structure and function. Neurogenic inflammatory-like processes and gut microbiome dysbiosis can also sensitize vagal afferents, providing a mechanism for visceral pain despite the loss of normal sensation post-SCI. These data may shed light on novel therapeutic interventions targeting this process to prevent NB development in patients.

Postoperative prolonged mechanical ventilation in patients with surgically treated pyogenic spondylodiscitis: a surrogate endpoint for early postoperative mortality

Surgical procedures with spinal instrumentation constitute a prevalent and occasionally highly indicated treatment modality in patients with pyogenic spondylodiscitis (PSD). However, surgical therapy might be associated with the need of prolonged postoperative intensive care medicine which in turn might impair intended operative benefit. Therefore, we analyzed prolonged mechanical ventilation (PMV) as an indicator variable for such intensive care treatment with regard to potential correlations with mortality in this vulnerable patient cohort. Between 2012 and 2018, 177 consecutive patients received stabilization surgery for PSD at the authors' neurosurgical department. PMV was defined as postoperative mechanical ventilation of more than 24 h. A multivariable analysis was performed to identify independent predictors for 30-day mortality. Twenty-three out of 177 patients (13%) with PSD suffered from postoperative PMV. Thirty-day mortality rate was 5%. Multivariable analysis identified "spinal empyema" (p = 0.02, odds ratio (OR) 6.2, 95% confidence interval (CI) 1.3-30.2), "Charlson comorbidity index (CCI) > 2" (p = 0.04, OR 4.0, 95% CI 1.0-15.5), "early postoperative complications (PSIs)" (p = 0.001, OR 17.1, 95% CI 3.1-96.0) and "PMV > 24 hrs" (p = 0.002, OR 13.0, 95% CI 2.7-63.8) as significant and independent predictors for early postoperative mortality. The present study indicates PMV to significantly correlate to elevated early postoperative mortality rates following stabilization surgery for PSD. These results might entail further scientific efforts to investigate PMV as a so far underestimated negative prognostic factor in the surgical treatment of PSD.

Is procalcitonin a reliable indicator of sepsis in spinal cord injury patients: an observational cohort study

STUDY DESIGN

Prospective observational cohort study.

OBJECTIVE

To understand if serum procalcitonin (PCT) is a reliable indicator of sepsis in spinal cord injury (SCI) patients for better prognosis and earlier diagnosis when compared with other common biomarkers such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cells (WBC), blood culture and body temperature.

METHODS

From March 2021 to August 2022, data were collected for SCI patients who developed septicaemia. In addition to neurology and admission, the following blood samples were collected on day one of infection: PCT, CRP and WBC. Linear regression analysis was performed to determine the relationship between PCT, CRP and WBC.

RESULTS

A total of 27 SCI patients had an infection during their stay in the regional centre; however, only 10 developed septicaemias. 100% of SCI individuals with sepsis had elevated PCT levels, whilst 60% had elevated CRP and 30% had elevated WBC levels. There was a strong positive correlation between PCT and CRP (R2 = 0.673, CI = 95%, 5.5-22.8, p < 0.05) and a weaker positive correlation between PCT and WBC (R2 = 0.110, CI = 95%, 4.2-10.9, p < 0.05).

CONCLUSION

In SCI individuals, there was a correlation between serum PCT levels and septicaemia. Alongside this, PCT appeared to be more consistent throughout the study population when compared with CRP and WBC. However, this was a preliminary study and further research is required on a larger scale.

Species Differences in Blood Lymphocyte Responses After Spinal Cord Injury

People with spinal cord injury (SCI) get recurrent infections, such as urinary tract infections (UTIs) and pneumonias, that cause mortality and worsen neurological recovery. Over the past decades, researchers have proposed that post-SCI lymphopenia and decreased lymphocyte function increase susceptibility to infections and worsen neurological outcome in humans, leading to a condition called SCI-induced immune depression syndrome (SCI-IDS). In this review, we explore how SCI affects blood lymphocyte homeostasis and function in humans and rodents. Understanding how SCI affects blood lymphocytes will help the management of recurrent infections in spinal cord injured people and shed light on the clinical translation of findings in animal models to humans.

Pharmacological and non-pharmacological therapeutic interventions for the treatment of spinal cord injury-induced pain

Spinal cord injury (SCI) is a complex neurophysiological disorder, which can result in many long-term complications including changes in mobility, bowel and bladder function, cardiovascular function, and metabolism. In addition, most individuals with SCI experience some form of chronic pain, with one-third of these individuals rating their pain as severe and unrelenting. SCI-induced chronic pain is considered to be "high impact" and broadly affects a number of outcome measures, including daily activity, physical and cognitive function, mood, sleep, and overall quality of life. The majority of SCI pain patients suffer from pain that emanates from regions located below the level of injury. This pain is often rated as the most severe and the underlying mechanisms involve injury-induced plasticity along the entire neuraxis and within the peripheral nervous system. Unfortunately, current therapies for SCI-induced chronic pain lack universal efficacy. Pharmacological treatments, such as opioids, anticonvulsants, and antidepressants, have been shown to have limited success in promoting pain relief. In addition, these treatments are accompanied by many adverse events and safety issues that compound existing functional deficits in the spinally injured, such as gastrointestinal motility and respiration. Non-pharmacological treatments are safer alternatives that can be specifically tailored to the individual and used in tandem with pharmacological therapies if needed. This review describes existing non-pharmacological therapies that have been used to treat SCI-induced pain in both preclinical models and clinical populations. These include physical (i.e., exercise, acupuncture, and hyper- or hypothermia treatments), psychological (i.e., meditation and cognitive behavioral therapy), and dietary interventions (i.e., ketogenic and anti-inflammatory diet). Findings on the effectiveness of these interventions in reducing SCI-induced pain and improving quality of life are discussed. Overall, although studies suggest non-pharmacological treatments could be beneficial in reducing SCI-induced chronic pain, further research is needed. Additionally, because chronic pain, including SCI pain, is complex and has both emotional and physiological components, treatment should be multidisciplinary in nature and ideally tailored specifically to the patient.

Machine Learning-based Prediction of Prolonged Intensive Care Unit Stay for Critical Patients with Spinal Cord Injury

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The objective of the study was to develop machine-learning (ML) classifiers for predicting prolonged intensive care unit (ICU)-stay and prolonged hospital-stay for critical patients with spinal cord injury (SCI).

SUMMARY OF BACKGROUND DATA

Critical patients with SCI in ICU need more attention. SCI patients with prolonged stay in ICU usually occupy vast medical resources and hinder the rehabilitation deployment.

METHODS

A total of 1599 critical patients with SCI were included in the study and labeled with prolonged stay or normal stay. All data were extracted from the eICU Collaborative Research Database and the Medical Information Mart for Intensive Care III-IV Database. The extracted data were randomly divided into training, validation and testing (6:2:2) subdatasets. A total of 91 initial ML classifiers were developed, and the top three initial classifiers with the best performance were further stacked into an ensemble classifier with logistic regressor. The area under the curve (AUC) was the main indicator to assess the prediction performance of all classifiers. The primary predicting outcome was prolonged ICU-stay, while the secondary predicting outcome was prolonged hospital-stay.

RESULTS

In predicting prolonged ICU-stay, the AUC of the ensemble classifier was 0.864 ± 0.021 in the three-time five-fold cross-validation and 0.802 in the independent testing. In predicting prolonged hospital-stay, the AUC of the ensemble classifier was 0.815 ± 0.037 in the three-time five-fold cross-validation and 0.799 in the independent testing. Decision curve analysis showed the merits of the ensemble classifiers, as the curves of the top three initial classifiers varied a lot in either predicting prolonged ICU-stay or discriminating prolonged hospital-stay.

CONCLUSION

The ensemble classifiers successfully predict the prolonged ICU-stay and the prolonged hospital-stay, which showed a high potential of assisting physicians in managing SCI patients in ICU and make full use of medical resources.Level of Evidence: 3.

High tidal volume ventilation is associated with ventilator-associated pneumonia in acute cervical spinal cord injury

CONTEXT/OBJECTIVE

Pneumonia is the leading cause of death after acute spinal cord injury (SCI). High tidal volume ventilation (HVtV) is used in SCI rehabilitation centers to overcome hypoventilation while weaning patients from the ventilator. Our objective was to determine if HVtV in the acute post-injury period in SCI patients is associated with lower incidence of ventilator-associated pneumonia (VAP) when compared to patients receiving standard tidal volume ventilation.

DESIGN

Cohort study.

SETTING

Red Duke Trauma Institute, University of Texas Health Science Center at Houston, TX, USA.

PARTICIPANTS

Adult Acute Cervical SCI Patients, 2011-2018.

INTERVENTIONS

HVtV.

OUTCOME MEASURES

VAP, ventilator dependence at discharge, in-hospital mortality.

RESULTS

Of 181 patients, 85 (47%) developed VAP. HVtV was utilized in 22 (12%) patients. Demographics, apart from age, were similar between patients who received HVtV and standard ventilation; patients were younger in the HVtV group. VAP developed in 68% of patients receiving HVtV and in 44% receiving standard tidal volumes (P = 0.06). After adjustment, HVtV was associated with a 1.96 relative risk of VAP development (95% credible interval 1.55-2.17) on Bayesian analysis. These results correlate with a >99% posterior probability that HVtV is associated with increased VAP when compared to standard tidal volumes. HVtV was also associated with increased rates of ventilator dependence.

CONCLUSIONS

While limited by sample size and selection bias, our data revealed an association between HVtV and increased VAP. Further investigation into optimal early ventilation settings is needed for SCI patients, who are at a high risk of VAP.