[Description of medicosocial profiles of pharmacodependent subjects consulting addictology centres using a computerized database]

INTRODUCTION

Lots of similar vulnerabilities to substance use disorders are described in the literature: clinical, genetics, family, environment, etc. Although, when we follow up patients, we know perfectly well that there are also differences due to the substance mainly causing addiction. But we found very little research on the differences between various substance use disorders according to the substance mainly causing dependence.

HYPOTHESIS

Our main hypothesis was that significant differences do not exist in medical and social data between patients with substance use disorders according to the substance mainly used. We expected to find significant differences between illegal substance use disorders (opiates, cocaine, cannabis) and legal substance use disorders (BZD, alcohol).

OBJECTIVE

Our study aimed to identify differences between patients with substance related disorders in medical and social data according to the main addictive substance.

MATERIAL AND METHOD

A specific software has been created by the CEIP and the Department of Addictology of Nantes University Hospital. Anonymous data were gathered and all patients gave their written consent. This database has been declared to CNIL (number 1350706). All data have been directly collected by the physician during medical consultation. The following data were recorded during the first medical examination: age, sex, illicit substance use, prior criminal record or psychiatric disorders, prior addictive behaviours among relatives and/or friends, family history (divorce, separation, abandonment). Other data were gathered prospectively: socioprofessional insertion, marital status, drug prescriptions (time and duration).

RESULTS

We found significant differences in social (age, sex) and medical data (prior psychiatric disorders) between patients according to the substance causing dependence. We identified five profiles depending on the substance: cannabis, cocaine, heroin, alcohol and benzodiazepine.

DISCUSSION

We clearly identified different types of patient's profiles according to substances mainly causing addiction. These differences can modify our strategies of prevention and treatment, so as to meet patients' needs better.

[Early neurorehabilitation in an acute university hospital: from dream to reality]

The need for an early neurorehabilitation pathway was identified in an acute university hospital. A team was formed to draw up and implement it. A neuro-sensorial, interdisciplinary and coordinated therapy program was developed, focused on tracheostomised patients as soon as they were admitted to the intermediate care in neurology and neurosurgery. The impact of this care plan was evaluated by comparing the results obtained with that pertaining to patients treated previously in the same services. The comparison showed a reduction of 48% of the mean duration of tracheostomy, of 39% in the time to inscription in a neurorehabilitation centre and of 20% in the length of stay in the intermediate care. An early neurorehabilitation care program, with an interdisciplinary and coordinated team, reduces complications and lengths of stay.

A liquid chromatography assay for a quantification of doripenem, ertapenem, imipenem, meropenem concentrations in human plasma: application to a clinical pharmacokinetic study

A simple chromatographic assay based on ultra high performance liquid chromatography with ultraviolet detection at 295 nm is proposed to determinate simultaneously human plasma concentrations of imipenem, doripenem, meropenem and ertapenem. After deproteinization by acetonitrile, carbapenems are separated on a PentaFluoroPhenyl column with a binary gradient elution. This method is specific, accurate, precise (the intra-day and inter-day imprecision and inaccuracy are lower than 15%), sensitive (the limit of quantitation is equal to 0.50 mg/L for imipenem, doripenem, ertapenem, meropenem) and not time consuming (run time=7 min). An application of this method to measure ertapenem plasma concentrations in burn patients is presented.

[Neurally adjusted ventilatory assist: a revolution of mechanical ventilation?]

Neurally adjusted ventilatory assist or NAVA is a new assisted ventilatory mode which, in comparison with pressure support, leads to improved patient-ventilator synchrony and a more variable ventilatory pattern. It also improves arterial oxygenation. With NAVA, the electrical activity of the diaphragm is recorded through a nasogastric tube equipped with electrodes. This electrical activity is then used to pilot the ventilator. With NAVA, the patient's respiratory pattern controls the ventilator's timing of triggering and cycling as well as the magnitude of pressurization, which is proportional to inspiratory demand. The effect of NAVA on patient outcome remains to be determined through well-designed prospective studies.

Online estimation of respiratory mechanics in non-invasive pressure support ventilation: a bench model study

An online algorithm for determining respiratory mechanics in patients using non-invasive ventilation (NIV) in pressure support mode was developed and embedded in a ventilator system. Based on multiple linear regression (MLR) of respiratory data, the algorithm was tested on a patient bench model under conditions with and without leak and simulating a variety of mechanics. Bland-Altman analysis indicates reliable measures of compliance across the clinical range of interest (± 11-18% limits of agreement). Resistance measures showed large quantitative errors (30-50%), however, it was still possible to qualitatively distinguish between normal and obstructive resistances. This outcome provides clinically significant information for ventilator titration and patient management.

Evaluation of the user-friendliness of seven new generation intensive care ventilators

OBJECTIVE

To explore the user-friendliness and ergonomics of seven new generation intensive care ventilators.

DESIGN

Prospective task-performing study.

SETTING

Intensive care research laboratory, university hospital.

METHODS

Ten physicians experienced in mechanical ventilation, but without prior knowledge of the ventilators, were asked to perform eight specific tasks [turning the ventilator on; recognizing mode and parameters; recognizing and setting alarms; mode change; finding and activating the pre-oxygenation function; pressure support setting; stand-by; finding and activating non-invasive ventilation (NIV) mode]. The time needed for each task was compared to a reference time (by trained physiotherapist familiar with the devices). A time >180 s was considered a task failure.

RESULTS

For each of the tests on the ventilators, all physicians' times were significantly higher than the reference time (P < 0.001). A mean of 13 +/- 8 task failures (16%) was observed by the ventilator. The most frequently failed tasks were mode and parameter recognition, starting pressure support and finding the NIV mode. Least often failed tasks were turning on the pre-oxygenation function and alarm recognition and management. Overall, there was substantial heterogeneity between machines, some exhibiting better user-friendliness than others for certain tasks, but no ventilator was clearly better that the others on all points tested.

CONCLUSIONS

The present study adds to the available literature outlining the ergonomic shortcomings of mechanical ventilators. These results suggest that closer ties between end-users and manufacturers should be promoted, at an early development phase of these machines, based on the scientific evaluation of the cognitive processes involved by users in the clinical setting.

Automated detection of asynchrony in patient-ventilator interaction

An automated classification algorithm for the detection of expiratory ineffective efforts in patient-ventilator interaction is developed and validated. Using this algorithm, 5624 breaths from 23 patients in a pulmonary ward were examined. The participants (N = 23) underwent both conventional and non-invasive ventilation. Tracings of patient flow, pressure at the airway, and transdiaphragmatic pressure were manually labeled by an expert. Overall accuracy of 94.5% was achieved with sensitivity 58.7% and specificity 98.7%. The results demonstrate the viability of using pattern classification techniques to automatically detect the presence of asynchrony between a patient and their ventilator.

Comparison between a liquid chromatography-tandem mass spectrometry assay and a fluorescent polarization immunoassay to measure whole blood everolimus concentration in heart and renal transplantations

Various methods [fluorescent polarization immunoassay (FPIA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay] are used for therapeutic drug monitoring of everolimus. The aim of this study is to compare these assays in renal and heart transplantation. The correlation between results was investigated by linear regression in 44 patients (24 heart recipients and 20 renal recipients--137 samples). The comparison between assays was performed by a paired t-test. A highly significant correlation was found between FPIA and LC-MS/MS in heart and renal recipients [FPIA=0.851 x LC-MS/MS+1.773r(2)=0.8738 (P<0.001)]. Paired t-tests did not show a significant difference between everolimus whole blood concentrations in the populations of heart and renal recipients or heart recipients or renal recipients. FPIA and LC-MS/MS assays gave consistent overall results although some significant differences were observed in some samples between these methods indicating that FPIA assay has limitations that deserve further investigations.

Population pharmacokinetics of domperidone in preterm neonates

PURPOSE

A population pharmacokinetic analysis was performed to define domperidone pharmacokinetic parameters in preterm neonates, as no pharmacokinetic data are available in this population.

METHODS

An oral domperidone solution was administered (0.75 mg/kg per day) in 32 preterm neonates (64 samples). Domperidone plasma concentration was measured by high-performance liquid chromatography (HPLC) assay, and a one-compartment model with first-order absorption was fitted to the data using NONMEM version V level 1.1.

RESULTS

The mean peak and trough plasma concentration values of domperidone were, respectively, 25.3 +/- 20.5 ng/ml and 15.4 +/- 11.4 ng/ml (mean +/- standard deviation). The pharmacokinetic parameters (interindividual variability%) were clearance (Cl/F) = 0.92 L/h (51.6%), volume of distribution (Vd/F) = 0.405 L (68%), and absorption constant rate (Ka) = 0.0843 h(-1) (55.8%). The clearance is not lower than values reported in adults. No influence of covariates (postnatal age, prematurity, weight, gender) on domperidone pharmacokinetic parameters was found.

CONCLUSION

This pilot study designed with a limited sampling strategy showed that domperidone plasma concentrations were consistent with those reported in adults, suggesting that domperidone dosage regimen currently used in preterm neonates is suitable.

Performance of noninvasive ventilation modes on ICU ventilators during pressure support: a bench model study

OBJECTIVE

Noninvasive ventilation (NIV) is often applied with ICU ventilators. However, leaks at the patient-ventilator interface interfere with several key ventilator functions. Many ICU ventilators feature an NIV-specific mode dedicated to preventing these problems. The present bench model study aimed to evaluate the performance of these modes.

DESIGN AND SETTING

Bench model study in an intensive care research laboratory of a university hospital.

METHODS

Eight ICU ventilators, widely available in Europe and featuring an NIV mode, were connected by an NIV mask to a lung model featuring a plastic head to mimic NIV conditions, driven by an ICU ventilator imitating patient effort. Tests were conducted in the absence and presence of leaks, the latter condition with and without activation of the NIV mode. Trigger delay, trigger-associated inspiratory workload, and pressurization were tested in conditions of normal respiratory mechanics, and cycling was also assessed in obstructive and restrictive conditions.

RESULTS

On most ventilators leaks led to an increase in trigger delay and workload, a decrease in pressurization, and delayed cycling. On most ventilators the NIV mode partly or totally corrected these problems, but with large variations between machines. Furthermore, on some ventilators the NIV mode worsened the leak-induced dysfunction.

CONCLUSIONS

The results of this bench-model NIV study confirm that leaks interfere with several key functions of ICU ventilators. Overall, NIV modes can correct part or all of this interference, but with wide variations between machines in terms of efficiency. Clinicians should be aware of these differences when applying NIV with an ICU ventilator.

Clinical review: patient-ventilator interaction in chronic obstructive pulmonary disease

Mechanically ventilated patients with chronic obstructive pulmonary disease often prove challenging to the clinician due to the complex pathophysiology of the disease and the high risk of patient-ventilator asynchrony. These problems are encountered in both intubated patients and those ventilated with noninvasive ventilation. Much knowledge has been gained over the years in our understanding of the mechanisms underlying the difficult interaction between these patients and the machines used to provide them with the ventilatory support they often require for prolonged periods. This paper attempts to summarize the various key issues of patient-ventilator interaction during pressure support ventilation, the most often used partial ventilatory support mode, and to draw clinicians' attention to the need for sufficient knowledge when setting the ventilator at the bedside, given the often conflicting goals that must be met.

Automatic adjustment of noninvasive pressure support with a bilevel home ventilator in patients with acute respiratory failure: a feasibility study

OBJECTIVE

To test the feasibility of applying noninvasive ventilation (NIV) using a prototype algorithm implemented in a bilevel ventilation device designed to adjust pressure support (PS) to maintain a clinician-set alveolar ventilation in patients with acute respiratory failure after initial stabilization.

DESIGN AND SETTING

Prospective crossover interventional study in an intensive care unit, university hospital.

PATIENTS

19 patients receiving NIV for acute hypercapnic respiratory failure (13 men, 6 women; mean age 70+/-11 years).

METHODS

The same bilevel ventilator was used with manually adjusted PS and with the automated algorithm (autoPS), set to maintain the same alveolar ventilation as in PS. Sequence (measurements at end of each period): (a) prior to initiating NIV (baseline 1); (b) 45 min with manually set PS; (c) 60 min without NIV; (d) 45 min with autoPS; (e) 60 min without NIV; (f) 45 min with manually set PS.

RESULTS

The magnitude of decrease in PaCO(2) and increase in pH with autoPS was comparable to that of conventional PS, with the same alveolar ventilation and level of PS. No technical problem occurred in autoPS mode, and no NIV trial had to be discontinued because of patient discomfort.

CONCLUSIONS

These results suggest that the alveolar ventilation based automatic control of PS during NIV with a bilevel device is feasible and leads to beneficial effects in patients with acute respiratory failure comparable to those of manually set PS. Further studies should now explore the potential of this system over longer periods in patients with acute and chronic respiratory failure.

Clinical review: agitation and delirium in the critically ill--significance and management

Agitation is a psychomotor disturbance characterized by a marked increase in motor and psychological activity in a patient. It occurs very frequently in the intensive care setting. It may be isolated, or accompanied by other mental disorders, such as severe anxiety and delirium. Frequently, agitation is a sign of brain dysfunction and, as such, may have adverse consequences, for at least two reasons. First, agitation can interfere with the patient's care and second, there is evidence demonstrating that the prognosis of agitated (and delirious) patients is worse than that of non-agitated (non-delirious) patients. These conditions are often under-diagnosed in the intensive care unit (ICU). Consequently, a systematic evaluation of this problem in ICU patients should be conducted. Excellent tools are presently available for this purpose. Treatment, including prevention, must be undertaken without delay, and the ICU physician should follow logical, strict and systematic rules when applying therapy.

Performance characteristics of five new anesthesia ventilators and four intensive care ventilators in pressure-support mode: a comparative bench study

BACKGROUND

During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators.

METHODS

Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed.

RESULTS

For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators.

CONCLUSION

Regarding trigger sensitivity and the system's ability to meet inspiratory flow during pressure-supported breaths, the most recent anesthesia ventilators have comparable performances of recent-generation intensive care unit ventilators.

[Should a helmet be used to deliver noninvasive ventilation?]

Patient comfort and tolerance are key factors determining the success of non-invasive ventilation (NIV). They are largely dependent on the interface used. Conti and Antonelli have developed a transparent helmet to improve patient tolerance during NIV. The main advantage of this device is patient comfort, adaptation to any morphological features, less leaks, and communication with others. The authors have demonstrated that CO2 rebreathing and middle ear dysfunction are not an issue when using the helmet. However, delayed inspiratory triggering, pressurization and cycling are of concern and require careful management by the caregiver, while a high cost must also be kept in mind. These issues mandate awareness of the indications (usually as second-line interface) and technical limitations and pitfalls of this promising interface.