Traumatic brain injury (TBI) is a major health and socioeconomic problem that affects all societies. In recent years, patterns of injury have been changing, with more injuries, particularly contusions, occurring in older patients. Blast injuries have been identified as a novel entity with specific characteristics. Traditional approaches to the classification of clinical severity are the subject of debate owing to the widespread policy of early sedation and ventilation in more severely injured patients, and are being supplemented with structural and functional neuroimaging. Basic science research has greatly advanced our knowledge of the mechanisms involved in secondary damage, creating opportunities for medical intervention and targeted therapies; however, translating this research into patient benefit remains a challenge. Clinical management has become much more structured and evidence based since the publication of guidelines covering many aspects of care. In this Review, we summarise new developments and current knowledge and controversies, focusing on moderate and severe TBI in adults. Suggestions are provided for the way forward, with an emphasis on epidemiological monitoring, trauma organisation, and approaches to management.

https://www.thelancet.com/pdfs/journals/laneur/PIIS1474-4422(08)70164-9.pdf

Moderate and severe traumatic brain injury in adults.

Context The need for lung protection is universally accepted, but the optimal level of positive end-expiratory pressure (PEEP) in patients with acute lung injury (ALI) or acute respiratory distress syndrome remains debated. Objective To compare the effect on outcome of a strategy for setting PEEP aimed at increasing alveolar recruitment while limiting hyperinflation to one aimed at minimizing alveolar distension in patients with ALI. Design, Setting, and Patients A multicenter randomized controlled trial of 767 adults (mean [SD] age, 59.9 [15.4] years) with ALI conducted in 37 intensive care units in France from September 2002 to December 2005. Intervention Tidal volume was set at 6 mL/kg of predicted body weight in both strategies. Patients were randomly assigned to a moderate PEEP strategy (5-9 cm H 2 O) (minimal distension strategy; n = 382)
or to a level of PEEP set to reach a plateau pressure of 28 to 30
cm H 2 O (increased recruitment strategy; n = 385). Main Outcome Measures The primary end point was mortality at 28 days. Secondary end points were hospital mortality at 60 days, ventilator-free days, and organ failure–free days at 28 days. Results The 28-day mortality rate in the minimal distension group was 31.2% (n = 119) vs 27.8% (n = 107) in the increased recruitment group (relative risk, 1.12 [95% confidence interval, 0.90-1.40]; P = .31). The hospital mortality rate in the minimal distension group was 39.0% (n = 149) vs 35.4%
(n = 136) in the increased recruitment group (relative risk,
1.10 [95% confidence interval, 0.92-1.32]; P = .30). The increased recruitment group compared with the minimal distension group had a higher median number of ventilator-free days (7 [interquartile range {IQR}, 0-19] vs 3 [IQR, 0-17]; P = .04) and organ failure–free days (6 [IQR, 0-18] vs 2 [IQR, 0-16]; P = .04).
This strategy also was associated with higher compliance values, better oxygenation, less use of adjunctive therapies, and larger fluid requirements. Conclusions A strategy for setting PEEP aimed at increasing alveolar recruitment while limiting hyperinflation did not significantly reduce mortality.
However, it did improve lung function and reduced the duration of mechanical ventilation and the duration of organ failure. Trial Registration clinicaltrials.gov Identifier: NCT00188058

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Positive end-expiratory pressure setting in adults with acute lung injury and acute respiratory distress syndrome: a randomized controlled trial.

Background Survival of patients with acute lung injury or the acute respiratory distress syndrome (ARDS) has been improved by ventilation with small tidal volumes and the use of positive end-expiratory pressure (PEEP); however, the optimal level of PEEP has been difficult to determine. In this pilot study, we estimated transpulmonary pressure with the use of esophageal balloon catheters. We reasoned that the use of pleuralpressure measurements, despite the technical limitations to the accuracy of such measurements, would enable us to find a PEEP value that could maintain oxygenation while preventing lung injury due to repeated alveolar collapse or overdistention. Methods We randomly assigned patients with acute lung injury or ARDS to undergo mechanical ventilation with PEEP adjusted according to measurements of esophageal pressure (the esophageal-pressure–guided group) or according to the Acute Respiratory Distress Syndrome Network standard-of-care recommendations (the control group). The primary end point was improvement in oxygenation. The secondary end points included respiratory-system compliance and patient outcomes. Results The study reached its stopping criterion and was terminated after 61 patients had been enrolled. The ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen at 72 hours was 88 mm Hg higher in the esophageal-pressure– guided group than in the control group (95% confidence interval, 78.1 to 98.3; P = 0.002). This effect was persistent over the entire follow-up time (at 24, 48, and 72 hours; P = 0.001 by repeated-measures analysis of variance). Respiratory-system compliance was also significantly better at 24, 48, and 72 hours in the esophagealpressure–guided group (P = 0.01 by repeated-measures analysis of variance). Conclusions As compared with the current standard of care, a ventilator strategy using esophageal pressures to estimate the transpulmonary pressure significantly improves oxygenation and compliance. Multicenter clinical trials are needed to determine whether this approach should be widely adopted. (ClinicalTrials.gov number, NCT00127491.)

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Mechanical Ventilation Guided by Esophageal Pressure in Acute Lung Injury

Introduction Morphological Analysis of the CT Images Early Phase [First Week] Late Stage [Second Week and Beyond] Long-Term Follow-up Pathogenesis Alters Morphology Quantitative Analysis of CT Scan Images CT Frequency Distribution Lung Compartments CT Scan Protocols and Analysis Influence Results One to Three Slices versus Whole Lung CT Scan Recruitment Hyperinflation and Overstretching Structure–Function Correlation in the Whole Lung Gas Exchange Lung Mechanics CT—Regional Analysis Edema Distribution and Lung Volume Superimposed Pressure and PEEP The CT Scan and Mechanical Ventilation Settings Opening the Lung Interaction between End Expiration and End Inspiration Distribution of Gas in Mechanical Ventilation Intratidal Collapse and Decollapse The Impact of CT Scanning in Clinical Practice New Developments and Future Areas of Research

/pdf/what-has-computed-tomography-taught-us-about-the-acute-57uustuxi9.pdf

What Has Computed Tomography Taught Us about the Acute Respiratory Distress Syndrome

Background
The “baby lung” concept originated as an offspring of computed tomography examinations which showed in most patients with acute lung injury/acute respiratory distress syndrome that the normally aerated tissue has the dimensions of the lung of a 5- to 6-year-old child (300–500 g aerated tissue).

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The concept of “baby lung”

We aimed to elucidate the relationships between pleural (Ppl), esophageal (Pes), and superimposed gravitational pressures in acute lung injury, and to understand the mechanisms of recruitment and derecruitment. In six dogs with oleic acid respiratory failure, we measured Pes and Ppl in the uppermost, middle, and most dependent lung regions. Each dog was studied at positive end-expiratory pressure (PEEP) of 5 and 15 cm H2O and three levels of tidal volume (Vt; low, medium, and high). For each PEEP–Vt combination, we obtained a computed tomographic (CT) scan at end-inspiration and end-expiration. The variations of Ppl and Pes pressures were correlated (r = 0.86 ± 0.07, p < 0.0001), as was the vertical gradient of transpulmonary (Pl) and superimposed pressure (r = 0.92, p < 0.0001). Recruitment proceeded continuously along the entire volume–pressure curve. Estimated threshold opening pressures were normally distributed (mode = 20 to 25 cm H2O). The amount of end-expiratory collapse at the same PEEP and Pl wa...

https://www.atsjournals.org/doi/pdf/10.1164/ajrccm.164.1.2007010

Recruitment and derecruitment during acute respiratory failure: an experimental study.

The presence of intracranial hypertension (HICP) after traumatic brain injury (TBI) affects patient outcome Intracranial pressure (ICP) data from electronic monitoring equipment are usually calculated and recorded hourly in the clinical chart by trained nurses Little is known, however, about how precisely this method reflects the real patterns of ICP after severe TBI In this study, we compared hourly manual recording with a validated and continuous computerized reference standard Thirty randomly selected patients with severe TBI and HICP admitted to the neuroscience intensive care unit (Policlinico University Hospital, Milan, Italy) were retrospectively studied A 24-hour interval with ICP monitoring was randomly selected for each patient The manually recorded data available for analysis covered 672 hours corresponding to 36,492 digital data points The two methods were evaluated using the correlation coefficient and the Bland and Altman method We used the proportion test to analyze differences in the number of episodes of HICP (ICP > 20 mm Hg) detected with the two methods and the paired t test to analyze differences in the percentage of time of HICP There was good agreement between the digitally collected ICP and the manual recordings of the end-hour values Bland and Altman analysis confirmed a mean difference between the two methods of 005 mm Hg (standard deviation 366); 96% of data were within the limits of agreement (+737 and -728) The average percentages of time of ICP greater than 20 mm Hg were 39% calculated from the digital measurements and 34% from the manual observations From the continuous digital recording, we identified 351 episodes of ICP greater than 20 mm Hg lasting at least five minutes and 287 similar episodes lasting at least ten minutes Conversely, end-hour ICP of greater than 20 mm Hg was observed in only 204 cases using manual recording methods Although manually recorded end-hour ICP accurately reflected the computerized end-hour and mean hour values, the important omission of a number of episodes of high ICP, some of long duration, results in a clinical picture that is not accurate or informative of the true pattern of unstable ICP in patients with TBI

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Intracranial pressure monitoring in intensive care: clinical advantages of a computerized system over manual recording.

To investigate the possibility of artificially decreasing intra-abdominal pressure (IAP) by applying continuous negative pressure around the abdomen. We investigated the effects of negative extra-abdominal pressure (NEXAP) on IAP and central venous pressure (CVP) in 30 patients admitted to our intensive care unit (age 57±17 years, BMI 26.1±4.0 kg/m2, SAPS II 41.8±17.0). Patients with severe hemodynamic instability and/or those admitted following a laparotomy were not studied. Measurements included bladder pressure as an estimate of IAP, CVP, invasive mean arterial pressure (MAP) and heart rate (HR). In five patients extensive hemodynamic measurements were also taken using a Swan-Ganz catheter. Following measurements at baseline (Basal), NEXAP (Life Care – Nev 100, Respironics) was applied on the abdomen, in random order, at a pressure equal to IAP (NEXAP0), 5 cmH2O (NEXAP-5) or 10 cmH2O (NEXAP-10) more negative than NEXAP0. Basal IAP ranged from 4 to 22 mmHg. NEXAP decreased IAP from 8.7±4.3 mmHg to 6±4.2 (Basal vs NEXAP0 p<0.001). There was a further decrease of IAP when more negative pressure was applied: 4.3±3.2 mmHg, 3.8±3.7 mmHg (NEXAP-5 and NEXAP-10 vs NEXAP0, respectively, p<0.001). Similarly, CVP decreased from 9.3±3.4 mmHg to 7.5±3.8 (Basal vs NEXAP-10, p<0.001). The lower the IAP when NEXAP was applied, the lower the CVP (r
 2
 =0.778, p<0.001, multiple linear regression). When measured, cardiac output did not significantly change with NEXAP. Negative extra-abdominal pressure may be applied in critically ill patients to decrease intra-abdominal pressure non-invasively.

https://link.springer.com/content/pdf/10.1007/s00134-003-2013-7

Intra-abdominal pressure may be decreased non-invasively by continuous negative extra-abdominal pressure (NEXAP).

/pdf/stress-in-nursing-staff-a-comparative-analysis-between-2gl4tr6dh5.pdf

S Losappio

Papers

Recruitment and derecruitment during acute respiratory failure: an experimental study.

Intracranial pressure monitoring in intensive care: clinical advantages of a computerized system over manual recording.

Intra-abdominal pressure may be decreased non-invasively by continuous negative extra-abdominal pressure (NEXAP).

Stress in nursing staff: a comparative analysis between intensive care units and general medicine units