Tracheotomy in the intensive care unit: guidelines from a French expert panel

Tracheotomy is widely used in intensive care units, albeit with great disparities between medical teams in terms of frequency and modality. Indications and techniques are, however, associated with variable levels of evidence based on inhomogeneous or even contradictory literature. Our aim was to conduct a systematic analysis of the published data in order to provide guidelines. We present herein recommendations for the use of tracheotomy in adult critically ill patients developed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. These guidelines were conducted by a group of experts from the French Intensive Care Society (Société de Réanimation de Langue Française) and the French Society of Anesthesia and Intensive Care Medicine (Société Francaise d'Anesthésie Réanimation) with the participation of the French Emergency Medicine Association (Société Française de Médecine d'Urgence), the French Society of Otorhinolaryngology. Sixteen experts and two coordinators agreed to consider questions concerning tracheotomy and its practical implementation. Five topics were defined: indications and contraindications for tracheotomy in intensive care, tracheotomy techniques in intensive care, modalities of tracheotomy in intensive care, management of patients undergoing tracheotomy in intensive care, and decannulation in intensive care. The summary made by the experts and the application of GRADE methodology led to the drawing up of 8 formal guidelines, 10 recommendations, and 3 treatment protocols. Among the 8 formal guidelines, 2 have a high level of proof (Grade 1+/-) and 6 a low level of proof (Grade 2+/-). For the 10 recommendations, GRADE methodology was not applicable and instead 10 expert opinions were produced.

Automaticversusmanual oxygen administration in the emergency department

Oxygen is commonly administered in hospitals, with poor adherence to treatment recommendations.

We conducted a multicentre randomised controlled study in patients admitted to the emergency department requiring O2≥3 L·min−1. Patients were randomised to automated closed-loop or manual O2titration during 3 h. Patients were stratified according to arterial carbon dioxide tension (PaCO2) (hypoxaemicPaCO2≤45 mmHg; or hypercapnicPaCO2>45–≤55 mmHg) and study centre. Arterial oxygen saturation measured by pulse oximetry (SpO2) goals were 92–96% for hypoxaemic, or 88–92% for hypercapnic patients. Primary outcome was % time withinSpO2target. Secondary endpoints were hypoxaemia and hyperoxia prevalence, O2weaning, O2duration and hospital length of stay.

187 patients were randomised (93 automated, 94 manual) and baseline characteristics were similar between the groups. Time within theSpO2target was higher under automated titration (81±21%versus51±30%, p<0.001). Time with hypoxaemia (3±9%versus5±12%, p=0.04) and hyperoxia under O2(4±9%versus22±30%, p<0.001) were lower with automated titration. O2could be weaned at the end of the study in 14.1%versus4.3% patients in the automated and manual titration group, respectively (p<0.001). O2duration during the hospital stay was significantly reduced (5.6±5.4versus7.1±6.3 days, p=0.002).

Automated O2titration in the emergency department improved oxygenation parameters and adherence to guidelines, with potential clinical benefits.

Automated oxygen titration and weaning with FreeO2 in patients with acute exacerbation of COPD: a pilot randomized trial

Introduction

We developed a device (FreeO₂) that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen.

Objective

The aim of this study was to evaluate the feasibility of using FreeO₂ in patients hospitalized in the respiratory ward for an acute exacerbation of COPD.

Methods

We conducted a randomized controlled trial comparing FreeO₂ vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO₂) as defined for each patient by the attending physician, the time with severe desaturation (SpO₂ <85%), and the time with hyperoxia (SpO₂ >5% above the target). We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O₂ flow 2.0±1.0 L/min).

Results

Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O₂ administration systems. The percentage of time within the SpO₂ target was significantly higher with FreeO₂, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO₂. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO₂ and 8.4±6.0 days with usual oxygen administration (P=0.051).

Conclusion

FreeO₂ was deemed as an appropriate oxygen administration system by nurses and physicians of a respiratory unit. This system maintained SpO₂ at the target level better than did manual titration and reduced periods of desaturation and hyperoxia. Our results also suggest that FreeO₂ has the potential to reduce the hospital length of stay.

Detection of artifacts on photoplethysmography signals using random distortion testing

In this work, we describe a novel method based on waveform morphology for detecting artifacts in photoplethysmography (PPG) signals and, thus, improve reliability of PPG. By considering inter-individual and measure condition variability, specific parameters are estimated for each record. We introduce a novel metric for comparing pulses, which is the derivative of the correlation coefficient. Then, we propose a detection method based on Random Distortion Testing (RDT), to perform adaptive threasholding for each record. The results show that the proposed method provides pertinent detection of pulses with artifacts. Tested on 104 PPG records, the mean of sensitivity, specificity and accuracy were 84 ± 16%, 83 ± 12% and 83 ± 8%, respectively.

Routine biological tests in self-poisoning patients: results from an observational prospective multicenter study

CONTEXT

Routine biological tests are frequently ordered in self-poisoning patients, but their clinical relevance is poorly studied.

MATERIALS AND METHODS

This is a prospective multicentric observational study conducted in the emergency departments and intensive care units of 5 university and nonuniversity French hospitals. Adult self-poisoning patients without severely altered vital status on admission were prospectively included.

RESULTS

Routine biological test (serum electrolytes and creatinine, liver enzymes, bilirubin, blood cell count, prothrombin time) ordering and results were analyzed. A total of 1027 patients were enrolled (age, 40.2 ± 14 years; women, 61.5%); no patient died during the hospital stay. Benzodiazepine was suspected in more than 70% of cases; 65% (range, 48%-80%) of patients had at least 1 routine biological test performed. At least 1 abnormal test was registered in 23% of these patients. Three factors were associated with abnormal test results: age older than 40 years, male sex, and poisoning with a drug known to alter routine tests (ie, acetaminophen, NSAIDs, metformine, lithium). Depending on these factors, abnormal results ranged from 14% to 48%. Unexpected severe life-threatening conditions were recorded in 6 patients. Only 3 patients were referred to the intensive care unit solely because of abnormal test results.

CONCLUSION

Routine biological tests are commonly prescribed in nonsevere self-poisoning patients. Abnormal results are frequent but their relevance at bedside remains limited.

Can lung ultrasonography predict prone positioning response in acute respiratory distress syndrome patients?

PURPOSE

The purpose was to assess whether lung ultrasonography (L-US) is a useful tool in prediction of prone positioning (PP) oxygenation response in patients with acute respiratory distress syndrome (ARDS).

METHODS

In a prospective study, 19 ARDS patients were included for assessment of PP oxygenation response. The latter was assessed for at least 12 hours 6 different ultrasonography windows were performed on each hemithorax before prone (H0, H2, H12 before return to supine and at H14 (2 hours after return to supine). Patients were classified into 2 groups (responders / non responders) according their oxygenation response to PP. Ultrasonography videos were blindly evaluated by 3 expert clinicians to classify lung regions as "normal", "moderate loss of aeration," "severe loss of aeration," or "lung consolidation." Oxygenation parameters were collected at H0, H2, and H14.

RESULTS

Association of each lung region aspect to PP oxygenation response was compared between the 2 groups. The normal aspect of the anterobasal regions was significantly associated with the oxygenation response (P = .0436), with a positive predictive value equal to or near 100%.

DISCUSSION

Our results demonstrated that a simple and short L-US examination could be a useful tool in prediction of PP oxygenation response in ARDS patients. A normal L-US pattern of both anterobasal lung regions in supine position may predict a significant PaO2/FIO2 ratio improvement.

Bench-test comparison of 26 emergency and transport ventilators

Introduction

Numerous emergency and transport ventilators are commercialized and new generations arise constantly. The aim of this study was to evaluate a large panel of ventilators to allow clinicians to choose a device, taking into account their specificities of use.

Methods

This experimental bench-test took into account general characteristics and technical performances. Performances were assessed under different levels of FIO₂ (100%, 50% or Air-Mix), respiratory mechanics (compliance 30,70,120 mL/cmH₂O; resistance 5,10,20 cmH₂O/mL/s), and levels of leaks (3.5 to 12.5 L/min), using a test lung.

Results

In total 26 emergency and transport ventilators were analyzed and classified into four categories (ICU-like, n = 5; Sophisticated, n = 10; Simple, n = 9; Mass-casualty and military, n = 2). Oxygen consumption (7.1 to 15.8 L/min at F_IO₂ 100%) and the Air-Mix mode (F_IO₂ 45 to 86%) differed from one device to the other. Triggering performance was heterogeneous, but several sophisticated ventilators depicted triggering capabilities as efficient as ICU-like ventilators. Pressurization was not adequate for all devices. At baseline, all the ventilators were able to synchronize, but with variations among respiratory conditions. Leak compensation in most ICU-like and 4/10 sophisticated devices was able to correct at least partially for system leaks, but with variations among ventilators.

Conclusion

Major differences were observed between devices and categories, either in terms of general characteristics or technical reliability, across the spectrum of operation. Huge variability of tidal volume delivery with some devices in response to modifications in respiratory mechanics and F_IO₂ should make clinicians question their use in the clinical setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0506-0) contains supplementary material, which is available to authorized users.

[A Serious Game for the prevention of risks in the home]

A Serious Game is a tool based on new technologies. It encompasses the notion of entertainment and learning. It has several purposes and is aimed at professionals as well as the general public. It can be used for educational purposes and integrated into training programmes.

Effect of induced mild hypothermia on two pro-inflammatory cytokines and oxidative parameters during experimental acute sepsis

This study aimed to determine the effect of induced mild hypothermia (34°C) on the production of two cytokines (interleukin (IL-6) and tumor necrosis factor (TNF)alpha) and reactive nitrogen and oxygen species in plasma and the heart of acutely septic rats. After anesthesia and in conditions of normothermia (38°C) or mild hypothermia (34°C), acute sepsis was induced by cecal ligation and perforation. For each temperature three groups were formed: (1) baseline (blood sample collected at T0 hour), (2) sham (blood sample at T4 hours) and (3) septic (blood sample at T4 hours). At either temperature sepsis induced a significant increase in plasma IL-6, TNF-alpha and HO• concentration, compared with the sham groups (P≤0.016). Compared with the normothermic septic group, septic rats exposed to mild hypothermia showed a mild decrease in TNF-alpha concentration (104±50 pg/ml vs. 215±114 pg/ml; P>0.05) and a significant decrease in IL-6 (1131±402 pg/ml vs. 2494±691 pg/ml, P=0.038). At either temperature sepsis induced no enhancement within the heart of lipoperoxidation (malondialdehyde content) or antioxidant activities (superoxide dismutase and catalase). In conclusion, during acute sepsis, induced mild hypothermia appears to reduce some pro-inflammatory and oxidative responses. This may, in part, explain the beneficial effect of hypothermia on survival duration of septic rats.

Comparison of usual and alternative methods to measure height in mechanically ventilated patients: potential impact on protective ventilation

BACKGROUND

Protective ventilation implementation requires the calculation of predicted body weight (PBW), determined by a formula based on gender and height. Consequently, height inaccuracy may be a limiting factor to correctly set tidal volumes. The objective of this study was to evaluate the accuracy of different methods in measuring heights in mechanically ventilated patients.

METHODS

Before cardiac surgery, actual height was measured with a height gauge while subjects were standing upright (reference method); the height was also estimated by alternative methods based on lower leg and forearm measurements. After cardiac surgery, upon ICU admission, a subject's height was visually estimated by a clinician and then measured with a tape measure while the subject was supine and undergoing mechanical ventilation.

RESULTS

One hundred subjects (75 men, 25 women) were prospectively included. Mean PBW was 61.0 ± 9.7 kg, and mean actual weight was 30.3% higher. In comparison with the reference method, estimating the height visually and using the tape measure were less accurate than both lower leg and forearm measurements. Errors above 10% in calculating the PBW were present in 25 and 40 subjects when the tape measure or visual estimation of height was used in the formula, respectively. With lower leg and forearm measurements, 15 subjects had errors above 10% (P < .001).

CONCLUSIONS

Our results demonstrate that significant variability exists between the different methods used to measure height in bedridden patients on mechanical ventilation. Alternative methods based on lower leg and forearm measurements are potentially interesting solutions to facilitate the accurate application of protective ventilation.

Evaluation of manual and automatic manually triggered ventilation performance and ergonomics using a simulation model

BACKGROUND

In the absence of endotracheal intubation, the manual bag-valve-mask (BVM) is the most frequently used ventilation technique during resuscitation. The efficiency of other devices has been poorly studied. The bench-test study described here was designed to evaluate the effectiveness of an automatic, manually triggered system, and to compare it with manual BVM ventilation.

METHODS

A respiratory system bench model was assembled using a lung simulator connected to a manikin to simulate a patient with unprotected airways. Fifty health-care providers from different professional groups (emergency physicians, residents, advanced paramedics, nurses, and paramedics; n = 10 per group) evaluated manual BVM ventilation, and compared it with an automatic manually triggered device (EasyCPR). Three pathological situations were simulated (restrictive, obstructive, normal). Standard ventilation parameters were recorded; the ergonomics of the system were assessed by the health-care professionals using a standard numerical scale once the recordings were completed.

RESULTS

The tidal volume fell within the standard range (400-600 mL) for 25.6% of breaths (0.6-45 breaths) using manual BVM ventilation, and for 28.6% of breaths (0.3-80 breaths) using the automatic manually triggered device (EasyCPR) (P < .0002). Peak inspiratory airway pressure was lower using the automatic manually triggered device (EasyCPR) (10.6 ± 5 vs 15.9 ± 10 cm H2O, P < .001). The ventilation rate fell consistently within the guidelines, in the case of the automatic manually triggered device (EasyCPR) only (10.3 ± 2 vs 17.6 ± 6, P < .001). Significant pulmonary overdistention was observed when using the manual BVM device during the normal and obstructive sequences. The nurses and paramedics considered the ergonomics of the automatic manually triggered device (EasyCPR) to be better than those of the manual device.

CONCLUSIONS

The use of an automatic manually triggered device may improve ventilation efficiency and decrease the risk of pulmonary overdistention, while decreasing the ventilation rate.

Determination of the learning curve for ultrasound-guided jugular central venous catheter placement

PURPOSE

Use of ultrasound (US) when introducing central venous catheters (CVC) may improve success rates, reduce the number of needle punctures, and decrease complication rates, but has been hampered by supposed difficulty in learning how to perform the technique. This study describes the learning curve for US-guided jugular CVC placement after a training program.

METHODS

After an initial slide presentation and a video, intensivists who had not previously used US for CVC placement were evaluated qualitatively for US set up (score S1) and technical skills (score S2). Quantitative measures included durations of different components of the procedure (T1, time from entry of the US into the patient's room to sterile dressing of the intensivist; T2, time needed for sterile drapes, venous line preparation, and sterile sheath placement; T3, time from skin puncture to venous flashback; T4, time from guide insertion to dressing; T(tot), total duration of the procedure); number of skin punctures; and a difficulty score allocated by the intensivist.

RESULTS

We performed 150 evaluations of 30 intensivists: 50% had no prior experience of CVC placement and 50% no prior US experience. Maximal S1 and S2 scores were obtained with the fourth and eighth placement procedures, respectively. T1 and T2 did not change with ongoing training (5 and 8 min, respectively), but T3 and T4 decreased, from 5 min (first procedure) to less than 1 min (seventh procedure), and from 10 min (first procedure) to 7 min (sixth procedure), respectively. T(tot) decreased from 34 to 21 min at the eighth procedure. The number of skin punctures and the difficulty score decreased rapidly with the number of evaluations.

CONCLUSIONS

Our study demonstrates that skills in US-guided CVC placement can easily be acquired with training.

Impact of humidification and nebulization during expiratory limb protection: an experimental bench study

BACKGROUND

Different filtering devices are used during mechanical ventilation to avoid dysfunction of flow and pressure transducers or for airborne microorganisms containment. Water condensates, resulting from the use of humidifiers, but also residual nebulization particles may have a major influence on expiratory limb resistance.

OBJECTIVES

To evaluate the influence of nebulization and active humidification on the resistance of expiratory filters.

METHODS

A respiratory system analog was constructed using a test lung, an ICU ventilator, heated humidifiers, and a piezoelectric nebulizer. Humidifiers were connected to different types of circuits (unheated, mono-heated, new-generation and old-generation bi-heated). Five filter types were evaluated: electrostatic, heat-and-moisture exchanger, standard, specific, and internal heated high-efficiency particulate air [HEPA] filter. Baseline characteristics were obtained from each dry filter. Differential pressure measurements were carried out after 24 hours of continuous in vitro use for each condition, and after 24 hours of use with an old-generation bi-heated circuit without nebulization.

RESULTS

While using unheated circuits, measurements had to be interrupted before 24 hours for all the filtering devices except the internal heated HEPA filter. The heat-and-moisture exchangers occluded before 24 hours with the unheated and mono-heated circuits. The circuit type, nebulization practice, and duration of use did not influence the internal heated HEPA filter resistance.

CONCLUSION

Expiratory limb filtration is likely to induce several major adverse events. Expiratory filter resistance increase is due mainly to the humidification circuit type, rather than to nebulization. If filtration is mandatory while using an unheated circuit, a dedicated filter should be used for ≤ 24 hours, or a heated HEPA for a longer duration.

The semi-seated position slightly reduces the effort to breathe during difficult weaning

PURPOSE

The influence of posture on breathing effort in patients with difficult weaning is unknown. We hypothesized that posture could modulate the breathing effort in difficult-to-wean patients.

METHODS

A prospective, crossover, physiologic study was performed in 24 intubated patients breathing with pressure support who had already failed a spontaneous breathing trial or an extubation episode. Their median duration of mechanical ventilation before measurements was 25 days. Breathing pattern, occlusion pressure (P (0.1)), intrinsic PEEP (PEEP(i)), and inspiratory muscle effort evaluated by the pressure-time product of the respiratory muscles and the work of breathing were measured during three postures: the seated position in bed (90°LD), simulating the position in a chair, the semi-seated (45°), and the supine (0°) positions consecutively applied in a random order. A comfort score was obtained in 17 cooperative patients. The influence of position on chest wall compliance was measured in another group of 11 sedated patients.

RESULTS

The 45° position was associated with the lowest levels of effort (p ≤ 0.01) and occlusion pressure (p < 0.05), and tended to be more often comfortable. Respiratory effort was the lowest at 45° in 18/24 patients. PEEP(i) and PEEP(i)-related work were slightly higher in the supine position (p ≤ 0.01), whereas respiratory effort, heart rate, and P (0.1) values were increased in the seated position (p < 0.05).

CONCLUSION

A 45° position helps to unload the respiratory muscles, moderately reduces PEEP(i), and is often considered as comfortable. The semi-seated position may help the weaning process in ventilator-dependent patients.

[Current trends in plasma transfusion for patients with severe hemorrhage]

Recent changes in plasma transfusion practices for severe hemorrhage are largely related to the recognition of an early endogenous coagulopathy associated with traumatic injury. Observational and mostly retrospective data suggest improved survival rates with high-dose plasma therapy, up to a 1:1 ratio of fresh frozen plasma to packed red blood cells, but the quality of evidence is limited. Putting it into practice raises many issues (early identification of patients at risk of massive bleeding, extrapolation to non-trauma settings, alternative or adjunctive treatments, among others) that are discussed in this brief review.

Noninvasive ventilation and weaning in patients with chronic hypercapnic respiratory failure: a randomized multicenter trial

RATIONALE

The use of noninvasive ventilation (NIV) as an early weaning/extubation technique from mechanical ventilation remains controversial.

OBJECTIVES

To investigate NIV effectiveness as an early weaning/extubation technique in difficult-to-wean patients with chronic hypercapnic respiratory failure (CHRF).

METHODS

In 13 intensive care units, 208 patients with CHRF intubated for acute respiratory failure (ARF) who failed a first spontaneous breathing trial were randomly assigned to three groups: conventional invasive weaning group (n = 69), extubation followed by standard oxygen therapy (n = 70), or NIV (n = 69). NIV was permitted as rescue therapy for both non-NIV groups if postextubation ARF occurred. Primary endpoint was reintubation within 7 days after extubation. Secondary endpoints were: occurrence of postextubation ARF or death within 7 days after extubation, use of rescue postextubation NIV, weaning time, and patient outcomes.

MEASUREMENTS AND MAIN RESULTS

Reintubation rates were 30, 37, and 32% for invasive weaning, oxygen-therapy, and NIV groups, respectively (P = 0.654). Weaning failure rates, including postextubation ARF, were 54, 71, and 33%, respectively (P < 0.001). Rescue NIV success rates for invasive and oxygen-therapy groups were 45 and 58%, respectively (P = 0.386). By design, intubation duration was 1.5 days longer for the invasive group than in the two others. Apart from a longer weaning time in NIV than in invasive group (2.5 vs. 1.5 d; P = 0.033), no significant outcome difference was observed between groups.

CONCLUSIONS

No difference was found in the reintubation rate between the three weaning strategies. NIV decreases the intubation duration and may improve the weaning results in difficult-to-wean patients with CHRF by reducing the risk of postextubation ARF. The benefit of rescue NIV in these patients deserves confirmation.