Triage and monitoring of COVID-19 patients in intensive care using unsupervised machine learning

BACKGROUND

We designed an algorithm to assess COVID-19 patients severity and dynamic intubation needs and predict their length of stay using the breathing frequency (BF) and oxygen saturation (SpO₂) signals.

METHODS

We recorded the BF and SpO₂ signals for confirmed COVID-19 patients admitted to the ICU of a teaching hospital during both the first and subsequent outbreaks of the pandemic in France. An unsupervised machine-learning algorithm (the Gaussian mixture model) was applied to the patients' data for clustering. The algorithm's robustness was ensured by comparing its results against actual intubation rates. We predicted intubation rates using the algorithm every hour, thus conducting a severity evaluation. We designed a S₂₄ severity score that represented the patient's severity over the previous 24 h; the validity of MS₂₄, the maximum S₂₄ score, was checked against rates of intubation risk and prolonged ICU stay.

RESULTS

Our sample included 279 patients. . The unsupervised clustering had an accuracy rate of 87.8% for intubation recognition (AUC = 0.94, True Positive Rate 86.5%, true Negative Rate 90.9%). The S₂₄ score of intubated patients was significantly higher than that of non-intubated patients at 48 h before intubation. The MS₂₄ score allowed for the distinguishing between three severity levels with an increased risk of intubation: green (3.4%), orange (37%), and red (77%). A MS₂₄ score over 40 was highly predictive of an ICU stay greater than 5 days at an accuracy rate of 81.0% (AUC = 0.87).

CONCLUSIONS

Our algorithm uses simple signals and seems to efficiently visualize the patients' respiratory situations, meaning that it has the potential to assist staffs' in decision-making. Additionally, real-time computation is easy to implement.

French multicentre observational study on SARS-CoV-2 infections intensive care initial management: the FRENCH CORONA study

AIM

Describing acute respiratory distress syndrome patterns, therapeutics management, and outcomes of ICU COVID-19 patients and indentifying risk factors of 28-day mortality.

METHODS

Prospective multicentre, cohort study conducted in 29 French ICUs. Baseline characteristics, comorbidities, adjunctive therapies, ventilatory support at ICU admission and survival data were collected.

RESULTS

From March to July 2020, 966 patients were enrolled with a median age of 66 (interquartile range 58-73) years and a median SAPS II of 37 (29-48). During the first 24 h of ICU admission, COVID-19 patients received one of the following respiratory supports: mechanical ventilation for 559 (58%), standard oxygen therapy for 228 (24%) and high-flow nasal cannula (HFNC) for 179 (19%) patients. Overall, 721 (75%) patients were mechanically ventilated during their ICU stay. Prone positioning and neuromuscular blocking agents were used in 494 (51%) and 460 (48%) patients, respectively. Bacterial co-infections and ventilator-associated pneumonia were diagnosed in 79 (3%) and 411 (43%) patients, respectively. The overall 28-day mortality was 18%. Age, pre-existing comorbidities, severity of respiratory failure and the absence of antiviral therapy on admission were identified as independent predictors of 28-day outcome.

CONCLUSION

Severity of hypoxaemia on admission, older age (> 70 years), cardiovascular and renal comorbidities were associated with worse outcome in COVID-19 patients. Antiviral treatment on admission was identified as a protective factor for 28-day mortality. Ascertaining the outcomes of critically ill COVID-19 patients is crucial to optimise hospital and ICU resources and provide the appropriate intensity level of care.

Complex and prolonged hypercoagulability in coronavirus disease 2019 intensive care unit patients: A thromboelastographic study

BACKGROUND

A high number of thrombotic complications have been reported in critically ill patients with coronavirus disease 2019 (COVID-19) and appear to be related to a hypercoagulable state. Evidence regarding detection, management, and monitoring of COVID-19-associated coagulopathy is still missing. We propose to describe the thrombus viscoelastic properties to investigate the mechanisms of hypercoagulability in patients with COVID-19.

METHODS

Thromboelastography (TEG) was performed in 24 consecutive patients admitted to a single intensive care unit for COVID-19 pneumonia, and 10 had a second TEG before being discharged alive from the intensive care unit.

RESULTS

Compared with a group of 20 healthy participants, patients with COVID-19 had significantly decreased values of reaction time, coagulation time, and lysis index and increased values of α angle, maximum amplitude, clot strength, and coagulation index. Velocity curves were consistent with increased generation of thrombin. These values persisted in surviving patients despite their good clinical course.

DISCUSSION

In patients with COVID-19, TEG demonstrates a complex and prolonged hypercoagulable state including fast initiation of coagulation and clot reinforcement, low fibrinolysis, high potential of thrombin generation, and high fibrinogen and platelet contribution. The antithrombotic strategy in patients with COVID-19 during intensive care hospitalisation and after discharge should be investigated in further studies.

Lessons Learned on the Battlefield Applied in a Civilian Setting

We report the case of a civilian 27-year-old man treated in a military hospital in France who sustained multiple stab wounds, including one in the left groin, with massive external bleeding. When first responders arrived, the patient was in hemorrhagic shock. A tourniquet and two intraosseous catheters were placed to start resuscitative care. On the patient's arrival at the hospital, bleeding was not controlled, so a junctional tourniquet was put in place and massive transfusion was started. Surgical exploration revealed a laceration of the superficial femoral artery and a disruption of the femoral vein. Vascular damage control was achieved by a general surgeon and consisted of primary repair of the superficial femoral artery injury and venous ligation. The patient was discharged from the intensive care unit after 2 days and from the hospital after 8 days. This case illustrates some of the persistent challenges shared between military and civilian trauma care. The external control of junctional hemorrhage is not easily achievable in the field, and junctional tourniquets have been therefore incorporated in the Tactical Combat Casualty Care guidelines. French lyophilized plasma was used for massive transfusion because it has been proven to be a logistically superior alternative to fresh-frozen plasma. Management of vascular wounds by nonspecialized surgeons is a complex situation that requires vascular damage-control skills; French military surgeons therefore follow a comprehensive structured surgical training course that prepares them to manage complex penetrating trauma in austere environments. Finally, in this case, lessons learned on the battlefield were applied to the benefit of the patient.

Transfusion de sang total : quelle place dans la réanimation du choc hémorragique traumatique ?

La transfusion sanguine s’est développée et a progressé au rythme des conflits militaires. La découverte des groupes sanguins et des règles de compatibilité croisée a permis d’identifier des « donneurs universels ». Le fractionnement du sang total et le stockage différencié de ses différents composants ont permis d’améliorer la sécurité transfusionnelle et la conservation des produits sanguins.  Alors que la majorité des décès évitables en traumatologie sont liés à des hémorragies massives, les engagements militaires récents ont mis en évidence l’intérêt d’une réanimation transfusionnelle précoce et ciblée contre la coagulopathie. À la phase aiguë, globules rouges, facteurs de coagulation et plaquettes sont pour cette raison administrés selon une stratégie de ratios transfusionnels. Cette stratégie se heurte à des difficultés logistiques liées aux différentes conditions de conservation de ces produits, à leur délai de délivrance, et à la charge de travail que leur transfusion impose dans le contexte de l’urgence. Dans des environnements contraints, le prélèvement et la transfusion de sang total frais est resté une technique de recours qui a montré son intérêt clinique et logistique. Plusieurs équipes civiles et militaires ont démontré la possibilité de conserver à 4° C puis de transfuser du sang total de groupe O faiblement titré en hémolysine, afin d’obtenir une thérapeutique de réanimation transfusionnelle universelle et disponible sans délai.

Rapid sequence induction traceability in an ICU dedicated patient data management system: a multicentric retrospective study

PURPOSE

Patient data management systems (PDMS) are widely used in intensive care units (ICUs) to improve care traceability. Verbal orders are still used for prescriptions requiring immediate execution but should be subsequently recorded in the system. We assessed the rapid sequence induction (RSI) traceability for endotracheal intubation in an ICU dedicated PDMS.

MATERIALS AND METHODS

A retrospective study was conducted on anonymous databases in 21 ICUs. Endotracheal tube insertions performed during one year were compared to the number of RSI registered in the PDMS.

RESULTS

We listed 5516 endotracheal tube insertions. A suxamethonium injection was registered in 829 cases and a rocuronium administration in 909 cases. The RSI traceability rate in the overall cohort was 31.5% and was greater in the units where nurses were allowed to record a drug administration before the computerized physician order entry.

CONCLUSIONS

PDMS are supposed to improve prescription completeness and traceability, but our study suggests an opposite result. A co-responsibility policy between physicians and nurses should be promoted to improve care traceability. PDMS ergonomic improvements and enhanced integration in clinical workflow might also result in better compliance with documentation requirements. In each centre, indicators of PDMS correct use should be defined and periodically monitored.

Health workers' safety during tracheostomy in COVID-19 patients: Homemade protective screen

As an aerosol and droplets generating procedure, tracheostomy increases contamination risks for health workers in the coronavirus disease context. To preserve the health care system capacity and to limit virus cross‐transmission, protecting caregivers against coronavirus infection is of critical importance. We report the use of external fixator equipment to set up a physical interface between the patient's neck and the caregiver performing a tracheostomy in COVID‐19 patients. Once the metal frame set in place, it is wrapped with a single‐use clear and sterile cover for surgical C‐arm. This installation is simple, easy, and fast to achieve and can be carried out with inexpensive material available in every hospital. This physical interface is an additional safety measure that prevents the direct projection of secretions or droplets. It should, of course, only be considered as a complement to strict compliance with barrier precautions and personal protective equipment.

Occupational Exposures to Ebola Virus in Ebola Treatment Center, Conakry, Guinea

We report 77 cases of occupational exposures for 57 healthcare workers at the Ebola Treatment Center in Conakry, Guinea, during the Ebola virus disease outbreak in 2014−2015. Despite the high incidence of 3.5 occupational exposures/healthcare worker/year, only 18% of workers were at high risk for transmission, and no infections occurred.

Patterns of invasive mechanical ventilation in patients with severe blunt chest trauma and lung contusion: A French multicentric evaluation of practices

Introduction

This study investigated invasive mechanical ventilation modalities used in severe blunt chest trauma patients with pulmonary contusion. Occurrence, risk factors, and outcomes of early onset acute respiratory distress syndrome were also evaluated.

Methods

We performed a retrospective multicenter observational study including 115 adult patients hospitalized in six level 1 trauma intensive care units between April and September of 2014. Independent predictors of early onset acute respiratory distress syndrome were determined by multiple logistic regression analysis based on clinical characteristics and initial management.

Results

Protective ventilation principles were highly implemented, even prophylactically before acute respiratory distress syndrome occurrence. Early onset acute respiratory distress syndrome appeared to be associated with lung contusion of >20% of total lung volume and early onset pneumonia.

Conclusions

Predictors of early onset acute respiratory distress syndrome could help with identifying high-risk populations, potentially improving case management through specific protocol development for these patients.

Fluid resuscitation in Ebola Virus Disease: A comparison of peripheral and central venous accesses

INTRODUCTION

Ebola Virus Disease (EVD) causes severe diarrhoea and vomiting, leading to dehydration and electrolyte abnormalities. Treatment remains supportive and often requires intravenous (IV) access. IV catheters are difficult to insert and maintain in this context. Our primary objective was to compare peripheral venous catheters (PVCs) and central venous catheters (CVCs) for volume resuscitation in patients with EVD.

MATERIAL AND METHODS

We performed a prospective observational study between January and March 2015 at the Conakry Healthcare Workers Ebola Treatment Unit (ETU). The primary judgement criterion was the ratio of the daily infused volume of fluids to the prescribed volume (DIV/PV).

RESULTS

Fourteen patients were admitted. Twenty-eight PVCs and 8 CVCs were inserted. CVCs had a longer survival time (96 ± 34 hours versus 33.5 ± 21 hours, P<0.001). The mean DIV/PV was higher for the CVCs (0.95±0.08 versus 0.7 ± 0.27, P<0.001), as well as the number of days with full administration of prescribed IV fluids (71.2% versus 34.1%, P=0.002).

DISCUSSION

Inserting CVCs is a safe and reliable way of obtaining IV access in ETUs, provided adequately trained personnel are available. CVCs optimize fluid infusion compared to PVCs. Further studies comparing fluid management strategies in EVD are necessary.

Rhabdomyolysis in Ebola Virus Disease. Results of an Observational Study in a Treatment Center in Guinea

BACKGROUND

The pathogenesis of Ebola virus disease (EVD) remains unclear. The sporadic nature of Ebola outbreaks and their occurrence in resource-limited settings have precluded the acquisition of extensive clinical and laboratory data. Rhabdomyolysis during EVD has been suggested to occur in previous studies showing increased aspartate aminotransferase-alanine aminotransferase ratios, but, to date, has not been confirmed with creatine kinase (CK) assays.

METHODS

We performed an observational study of 38 patients admitted to an Ebola treatment center from January to April 2015. CK values from patients with confirmed EVD were compared with those in patients without confirmed EVD. A panel of other analyses were also performed. In patients with EVD, characteristics were compared between survivors and nonsurvivors.

RESULTS

High levels of CK were more frequent in patients with EVD than in those without (P = .002), and rhabdomyolysis was more frequent (59% vs 19%, respectively; P = .03). CK levels >5000 U/L were observed in 36% of patients with EVD. Also in patients with EVD, fatal outcome was significantly associated with higher creatinine and bilirubin levels, international normalized ratio, and viral load.

CONCLUSIONS

Rhabdomyolysis is a frequent disorder in EVD and seems to be more common than in other viral infections. It may contribute to the renal failure observed in nonsurviving patients. More studies are needed to determine the impact of rhabdomyolysis on EVD outcome.

Is critical illness polyneuropathy associated with decreased heart rate variability?

INTRODUCTION

This pilot study assessed the association between critical illness polyneuropathy (CIP) and decreased heart rate variability (HRV) in intensive care patients.

METHODS

All patients admitted to the intensive care unit and expected to be ventilated for at least 72 hours were included and underwent weekly electromyograms and HRV analyses for three weeks. HRV was assessed by time domain analysis of 24h recording electrocardiograms, and alterations in HRV were assessed as the square root of the mean squared differences of successive RR intervals (RMSSD) ≤ 15.

RESULTS

We evaluated 26 patients, 12 men and 14 women, median age 64 years. During follow-up, 12 patients died and 9 developed CIP. CIP was not associated with age, sex, simplified acute physiology score II and treatment agents. Altered RMSSD tended to be associated with onset of CIP (P=0.06). Altered RMSSD occurred earlier or at the same time as electromyogram abnormalities in all CIP patients, but the difference was not significant.

CONCLUSION

Altered HRV, may be associated with the onset of CIP in ICU patients. Although not statistically significant (P=0.06), altered RMSSD may be a surrogate marker of CIP in ICU patients undergoing mechanical ventilation. The physiological pathway linking HRV and CIP remains uncertain.

5-FU-induced neurotoxicity in cancer patients with profound DPD deficiency syndrome: a report of two cases

PURPOSE

5-Fluorouracil (5-FU) is a mainstay for treating various solid tumours in adults, including digestive and head and neck cancers. 5-FU-related toxicities usually include haematological, digestive and cutaneous features. Additionally, 5-FU has been described as being potentially neurotoxic in patients, but these side effects are quite rare in clinical practice. Here, we report two cases of sudden and unpredictable drug-induced neurotoxicities that occurred in patients undergoing their first course of 5-FU-based chemotherapy.

PATIENTS AND METHODS

None of these patients had any previous neurological disorder history, and both were treated following standard regimen (LV-5-FU2 and TPF for patient 1 and 2, respectively). Neurotoxicity included drowsiness, acute confusion plus dysarthria for the first patient and seizure, confusion and signs of metabolic encephalopathy for the second one. In addition, typical 5-FU-related severe toxicities (e.g. neutropenia and mucosities) were observed. Both patients slowly recovered from these neurological toxicities under supportive treatment. It was assumed that overexposure to 5-FU could explain the severe toxicities encountered. To test this hypothesis, we retrospectively evaluated the dihydropyrimidine dehydrogenase (DPD) activity of these patients on a phenotypic basis.

RESULTS

Evaluation of the uracil-to-di-hydrouracil (U/UH2) ratio in plasma revealed a profound DPD deficiency syndrome in both patients.

CONCLUSION

These cases suggest that 5-FU standard dosage administration may lead to strong overexposure, responsible for the severe toxicities observed, including the neurological features. It implies that DPD deficiency can cause neurotoxicity in 5-FU-treated patients and advocates for the prospective screening of DPD deficiency before starting any 5-FU-containing chemotherapy so as to prevent such side effects in the future.

Lanthanide(III) Complexes of Tripodal N-Donor Ligands: Structural Models for the Species Involved in Solvent Extraction of Actinides(III)

The complexation of lanthanides(III) by the tripodal ligands tpa (tris[(2-pyridyl)methyl]amine) and tpza (tris[(2-pyrazinyl)methyl]amine) has been investigated by solution NMR studies and by X-ray crystallography. The crystallographic studies show that both tpa and the new ligand tpza form complexes with a 1:1 metal:ligand ratio in which the tripodal amine acts as a tetradentate ligand. For the tpa complexes the remaining coordination sites are occupied by chloride counterions to give 7-coordination (Eu, Tb, Lu) or by chloride counterions and a methanol molecule to give 8-coordination (Nd). In [Nd(tpza)(H(2)O)(3)(CH(3)CN)(3)](ClO(4))(3).3H(2)O the remaining coordination sites are occupied by water and acetonitrile molecules to give 10-coordination while the perchlorate counterions remain non coordinating. Tpza complexes have been isolated from acetonitrile solution and dissociate completely in methanol, while the complexes of the more basic tpa can be isolated from methanol and exist in water in equilibrium with the free ligand. Solvent extraction studies of lanthanides(III) and actinides(III) from nitric acid solutions show that the new ligand tpza is, unlike tpa, a selective complexant of actinides(III). Considering their structural analogy, this difference could be explained in terms of the electronic differences between the two ligands resulting in a stronger affinity of actinides(III) for the softer donor tpza.