Comparison of prone positioning and continuous rotation of patients with adult respiratory distress syndrome: results of a pilot study

[Pathophysiology, Diagnostics and Therapy of Pulmonary Contusion - Recommendations of the Interdisciplinary Group on Thoracic Trauma of the Section NIS of the German Society for Trauma Surgery (DGU) and the German Society for Thoracic Surgery (DGT)]

Pulmonary contusion usually occurs in combination with other injuries and is indicative of a high level of force. Especially in multiply injured patients, pulmonary contusions are frequently detected. The injury is characterised by dynamic development, which might result in difficulties in recognising the actual extent of the injury at an early stage. Subsequently, correct classification of the extent of injury and appropriate initiation of therapeutic steps are essential to achieve the best possible outcome. The main goal of all therapeutic measures is to preserve lung function as best as possible and to avoid associated complications such as the development of pneumonia or Acute Respiratory Distress Syndrome (ARDS).The present report from the interdisciplinary working group "Chest Trauma" of the German Society for Trauma Surgery (DGU) and the German Society for Thoracic Surgery (DGT) includes an extensive literature review on the background, diagnosis and treatment of pulmonary contusion. Without exception, papers with a low level of evidence were included due to the lack of studies with large cohorts of patients or randomised controlled studies. Thus, the recommendations given in the present article correspond to a consensus of the aforementioned interdisciplinary working group.Computed tomography (CT) of the chest is recommended for initial diagnosis; the extent of pulmonary contusion correlates with the incidence and severity of complications. A conventional chest X-ray may initially underestimate the injury, but is useful during short-term follow-up.Therapy for pulmonary contusion is multimodal and symptom-based. In particular, intensive care therapy with lung-protective ventilation and patient positioning are key factors of treatment. In addition to invasive ventilation, non-invasive ventilation should be considered if the patient's comorbidities and compliance allows this. Furthermore, depending on the extent of the lung injury and the general patient's condition, ECMO therapy may be considered as an ultima ratio. In particular, this should only be performed at specialised hospitals, which is why patient assignment or anticipation of early transfer of the patient should be anticipated at an early time during the course.

The Impact of Sample Size Misestimations on the Interpretation of ARDS Trials: Systematic Review and Meta-analysis

BACKGROUND

Indeterminate randomized controlled trials (RCTs) in ARDS may arise from sample size misspecification, leading to abandonment of efficacious therapies.

RESEARCH QUESTIONS

If evidence exists for sample size misspecification in ARDS RCTs, has this led to rejection of potentially beneficial therapies? Does evidence exist for prognostic enrichment in RCTs using mortality as a primary outcome?

STUDY DESIGN AND METHODS

We identified 150 ARDS RCTs commencing recruitment after the 1994 American European Consensus Conference ARDS definition and published before October 31, 2020. We examined predicted-observed sample size, predicted-observed control event rate (CER), predicted-observed average treatment effect (ATE), and the relationship between observed CER and observed ATE for RCTs with mortality and nonmortality primary outcome measures. To quantify the strength of evidence, we used Bayesian-averaged meta-analysis, trial sequential analysis, and Bayes factors.

RESULTS

Only 84 of 150 RCTs (56.0%) reported sample size estimations. In RCTs with mortality as the primary outcome, CER was overestimated in 16 of 28 RCTs (57.1%). To achieve predicted ATE, interventions needed to prevent 40.8% of all deaths, compared with the original prediction of 29.3%. Absolute reduction in mortality ≥ 10% was observed in 5 of 28 RCTs (17.9%), but predicted in 21 of 28 RCTs (75%). For RCTs with mortality as the primary outcome, no association was found between observed CER and observed ATE (pooled OR: β = -0.04; 95% credible interval, -0.18 to 0.09). We identified three interventions that are not currently standard of care with a Bayesian-averaged effect size of > 0.20 and moderate strength of existing evidence: corticosteroids, airway pressure release ventilation, and noninvasive ventilation.

INTERPRETATION

Reporting of sample size estimations was inconsistent in ARDS RCTs, and misspecification of CER and ATE was common. Prognostic enrichment strategies in ARDS RCTs based on all-cause mortality are unlikely to be successful. Bayesian methods can be used to prioritize interventions for future effectiveness RCTs.

Impact of differences in acute respiratory distress syndrome randomised controlled trial inclusion and exclusion criteria: systematic review and meta-analysis

BACKGROUND

Control-arm mortality varies between acute respiratory distress syndrome (ARDS) RCTs.

METHODS

We systematically reviewed ARDS RCTs that commenced recruitment after publication of the American-European Consensus (AECC) definition (MEDLINE, Embase, and Cochrane central register of controlled trials; January 1994 to October 2020). We assessed concordance of RCT inclusion criteria to ARDS consensus definitions and whether exclusion criteria are strongly or poorly justified. We estimated the proportion of between-trial difference in control-arm 28-day mortality explained by the inclusion criteria and RCT design characteristics using meta-regression.

RESULTS

A literature search identified 43 709 records. One hundred and fifty ARDS RCTs were included; 146/150 (97.3%) RCTs defined ARDS inclusion criteria using AECC/Berlin definitions. Deviations from consensus definitions, primarily aimed at improving ARDS diagnostic certainty, frequently related to duration of hypoxaemia (117/146; 80.1%). Exclusion criteria could be grouped by rationale for selection into strongly or poorly justified criteria. Common poorly justified exclusions included pregnancy related, age, and comorbidities (infectious/immunosuppression, hepatic, renal, and human immunodeficiency virus/acquired immunodeficiency syndrome). Control-arm 28-day mortality varied between ARDS RCTs (mean: 29.8% [95% confidence interval: 27.0-32.7%; I2=88.8%; τ2=0.02; P<0.01]), and differed significantly between RCTs with different Pao2:FiO2 ratio inclusion thresholds (26.6-39.9 kPa vs <26.6 kPa; P<0.01). In a meta-regression model, inclusion criteria and RCT design characteristics accounted for 30.6% of between-trial difference (P<0.01).

CONCLUSIONS

In most ARDS RCTs, consensus definitions are modified to use as inclusion criteria. Between-RCT mortality differences are mostly explained by the Pao2:FiO2 ratio threshold within the consensus definitions. An exclusion criteria framework can be applied when designing and reporting exclusion criteria in future ARDS RCTs.

Critical Care Beds With Continuous Lateral Rotation Therapy to Prevent Ventilator-Associated Pneumonia and Hospital-Acquired Pressure Injury: A Cost-effectiveness Analysis

OBJECTIVES

Mechanical ventilation increases the risk of hospital-acquired conditions (HACs) such as ventilator-associated pneumonia (VAP) and pressure injury (PrI). Beds with continuous lateral rotation therapy (CLRT) are shown to reduce HAC incidence, but the value of switching to CLRT beds is presently unknown. We compared the cost-effectiveness of CLRT beds with standard care in intensive care units.

METHODS

A cost-effectiveness analysis from the healthcare sector and societal perspectives was conducted. A Markov model was constructed to predict health state transitions from time of ventilation through 28 days for the healthcare sector perspective and 1 year for the U.S. societal perspective. Value of information was calculated to determine whether parameter uncertainty warranted further research.

RESULTS

Our analysis suggested that CLRT beds dominate standard care from both perspectives. From the healthcare sector perspective, expected cost for CLRT was U.S. $47,165/patient compared with a higher cost of U.S. $49,258/patient for standard care. The expected effectiveness of CLRT is 0.0418 quality-adjusted life years/patient compared with 0.0416 quality-adjusted life years/patient for standard care. Continuous lateral rotation therapy dominated standard care in approximately 93% of Monte Carlo simulations from both perspectives. Value of information analysis suggests that additional research is potentially cost-effective.

CONCLUSIONS

Continuous lateral rotation therapy is highly cost-effective compared with standard care by preventing HACs that seriously harm patients in the intensive care unit.

[Treatment options for acute respiratory distress syndrome in neurointensive care. Individual management due to enhanced neuromonitoring? : A case report series]

Severe pulmonary impairment can occur after traumatic brain injury or stroke. The resulting brain-lung interactions represent key points for the treatment and the subsequent outcome of the patient. Established treatment approaches, such as permissive hypercapnia and prone positioning, present the intensive care physician with divergent treatment goals in these patients with partially increased intracranial pressure. This case report series shows the instrument-based and noninstrument-based options for the treatment of acute respiratory distress syndrome (ARDS) in the simultaneous presence of intracranial pathologies. This includes equipment based therapies using extracorporeal CO₂ elimination, special positioning maneuvers in specially designed hospital beds and positional maneuvers, such as prone positioning. With enhanced neuromonitoring it is possible to optimally adapt treatment measures focused on the lungs early and before secondary damage to the brain.

[Continuous lateral rotational bed therapy in patients with traumatic lung injury: an analysis from the TraumaRegister DGU®]

BACKGROUND

Patients with severe thoracic trauma often receive continuous lateral rotational bed therapy (CLRT) for the treatment of lung contusions. In this study, the effects of CLRT on mortality, morbidity and length of stay (LOS) in the intensive care unit (ICU) and in the hospital were evaluated.

METHODS

Retrospective data from the TraumaRegister DGU® were analysed, focusing on patients with severe thoracic trauma. Patients treated with CLRT were compared to a control group with comparable trauma severity who had received conventional therapy.

RESULTS

A total of 1476 patients (239 with CLRT, 1237 without CLRT) were included in this study. Both groups were similar for demographic characteristics. The median CLRT duration was 6 (4-10) days. Patients receiving CLRT were ventilated for 17 (10-26) days compared to 14 (8-22) days (p = 0.001) in the control group. The ICU length of stay differed significantly (CLRT: 23 [14-32] days; control: 19 [13-28] days; p = 0.002). Also, organ failure occurred more frequently in patients treated with CLRT (CLRT: 76.6%, control: 67.6%; p = 0.006). No differences could be detected regarding mortality rates, multiple organ failure and hospital LOS.

CONCLUSIONS

The results of this retrospective analysis fail to detect a benefit for CLRT therapy in trauma patients. Considering inherent limitations of retrospective studies, caution should be exerted when interpreting these results. Further research is warranted to confirm these findings in a prospective trial.

Continuous lateral rotational therapy in trauma-A systematic review and meta-analysis

BACKGROUND

The purpose of this study was to evaluate the impact of continuous lateral rotational therapy (CLRT) on respiratory complications and mortality in patients suffering from trauma.

METHODS

The literature databases PubMed®/Medline® and the Cochrane Library® were systematically searched for prospective controlled trials comparing continuous lateral rotational therapy to conventional manual positioning in trauma patients.

RESULTS

A total of 8 publications (n= 422 patients) with comparable age and injury severity were included in the meta-analysis. A significant reduction in the incidence of nosocomial pneumonia (OR: 0.33, [95%CI: 0.17, 0.65], p=0.001) was observed in patients treated prophylactically with continuous lateral rotational therapy. When used with therapeutic intention, CLRT had no impact on the incidence of pneumonia. There were no significant differences in mortality, duration of mechanical ventilation, or ICU length of stay.

CONCLUSIONS

Analogous to studies evaluating CLRT in medical or mixed patient collectives, CLRT reduced the rates of nosocomial pneumonia in trauma patients. This, however, had no impact on overall mortality. The level of evidence of the studies included was limited by several factors. An adequately powered, well-designed multi-centre randomised controlled trial is required, to validly assess the utility of CLRT for the prevention and treatment of pulmonary complications in patients suffering from trauma.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

[Short version S2e guidelines: "Positioning therapy and early mobilization for prophylaxis or therapy of pulmonary function disorders"]

The German Society of Anesthesiology and Intensive Care Medicine (DGAI) commissioned a revision of the S2 guidelines on "positioning therapy for prophylaxis or therapy of pulmonary function disorders" from 2008. Because of the increasing clinical and scientific relevance the guidelines were extended to include the issue of "early mobilization" and the following main topics are therefore included: use of positioning therapy and early mobilization for prophylaxis and therapy of pulmonary function disorders, undesired effects and complications of positioning therapy and early mobilization as well as practical aspects of the use of positioning therapy and early mobilization. These guidelines are the result of a systematic literature search and the subsequent critical evaluation of the evidence with scientific methods. The methodological approach for the process of development of the guidelines followed the requirements of evidence-based medicine, as defined as the standard by the Association of the Scientific Medical Societies in Germany. Recently published articles after 2005 were examined with respect to positioning therapy and the recently accepted aspect of early mobilization incorporates all literature published up to June 2014.

S2e guideline: positioning and early mobilisation in prophylaxis or therapy of pulmonary disorders : Revision 2015: S2e guideline of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI)

The German Society of Anesthesiology and Intensive Care Medicine (DGAI) commissioneda revision of the S2 guidelines on "positioning therapy for prophylaxis or therapy of pulmonary function disorders" from 2008. Because of the increasing clinical and scientificrelevance the guidelines were extended to include the issue of "early mobilization"and the following main topics are therefore included: use of positioning therapy and earlymobilization for prophylaxis and therapy of pulmonary function disorders, undesired effects and complications of positioning therapy and early mobilization as well as practical aspects of the use of positioning therapy and early mobilization. These guidelines are the result of a systematic literature search and the subsequent critical evaluation of the evidence with scientific methods. The methodological approach for the process of development of the guidelines followed the requirements of evidence-based medicine, as defined as the standard by the Association of the Scientific Medical Societies in Germany. Recently published articles after 2005 were examined with respect to positioning therapy and the recently accepted aspect of early mobilization incorporates all literature published up to June 2014.

Combination of positioning therapy and venovenous extracorporeal membrane oxygenation in ARDS patients

Positioning therapy may improve lung recruitment and oxygenation and is part of the standard care in severe acute respiratory distress syndrome (ARDS). Venovenous extracorporeal membrane oxygenation (vvECMO) is a rescue strategy that may ensure sufficient gas exchange in ARDS patients failing conventional therapy. The aim of this case series was to describe the feasibility and pitfalls of combining positioning therapy and vvECMO in patients with severe ARDS.

A retrospective cohort of nine patients is described. The patients received 20 (15–86) hours (median, 25th and 75th percentile) of positioning therapy while being treated with vvECMO. The initial PaO2/FiO2 index was 64 (51–67) mmHg and the arterial carbon dioxide tension was 60 (50–71) mmHg. Positioning therapy included 135 degrees prone, prone positioning and continuous lateral rotational therapy. During the first three days, the oxygenation index improved from 47 (41–47) to 12 (11–14) cmH2O/mmHg. The lung compliance improved from 20 (17–28) to 42 (27–43) ml/cmH2O. Complications related to positioning therapy were facial oedema (n=9); complications related to vvECMO were entrance of air (n=1) and pump failure (n=1). However, investigation of root causes revealed no association with the positioning therapy and had no documented effect on the outcome.

The reported cases suggest that positioning therapy can be performed safely in ARDS patients treated with vvECMO, providing appropriate precautions are in place and a very experienced team is present.

[Positioning of patients with acute respiratory failure]

The collapse of lung tissue, edema and intrapulmonary shunt are the main symptoms in patients with acute respiratory insufficiency. The techniques of ventilation in a prone position and continuous lateral rotational therapy (CLRT) are based on these pathophysiological changes. Ventilation in a prone position was found to improve ventilation and perfusion relationships and reduction in the pleural pressure gradient. In hypoxemic lung failure (PaO(2)/FIO(2) <100) a prone position was found to improve oxygenation as a rescue measure and to improve survival. In contrast CLRT is considered to be an early therapeutic or prophylactic measure aimed at prevention of ventilation-associated complications. In trauma patients these beneficial effects were demonstrated in several studies. Positioning therapy can be accompanied by potentially serious complications (e.g. face and skin ulceration, accidental loss of tubes and catheters and cardiac arrhythmias) and its use requires routine management and exact knowledge of indications and risks.

A prospective, randomized trial of continuous lateral rotation ("kinetic therapy") in patients with cardiogenic shock

BACKGROUND

Continuous lateral rotation ["Kinetic therapy" (KT)] has been shown to reduce complications and to shorten hospital stay in trauma patients. Data in non-surgical patients is inconclusive. Retrospective data suggest a beneficial effect of KT in patients with cardiogenic shock (CS) requiring ventilator therapy. KT, however, has not been tested prospectively in those patients.

METHODS

A prospective, randomized, open-label trial was performed to compare KT using oscillating beds (TryaDyne Proventa, KCI) with standard care (SC). Patients with cardiogenic shock requiring ventilator therapy for more than 24 h were included. Primary endpoint was the occurrence of hospital-acquired pneumonia. Secondary endpoints were the occurrence of pressure ulcers during the hospital stay and 1-year all-cause mortality.

RESULTS

Forty-five patients were randomized to KT, and 44 to SC. All patients required at least one inotropic agent and one vasopressor for circulatory assistance. The groups were comparable in the etiology of heart disease, in the use of revascularization procedures, the use of balloon counterpulsation, and APACHE-II score (33 ± 5 vs. 33 ± 4) and SOFA score (11 ± 1 vs. 11 ± 1) at inclusion; however, more patients in SC were subject to resuscitation before inclusion. Hospital-acquired pneumonia occurred in 10 patients in KT and 28 patients in SC (p < 0.001); pressure ulcers were seen in 10 versus 2 patients (p < 0.001). Hospital mortality tended to be lower in KT, and 1-year all-cause mortality was 41 % in KT and 66 % in SC (p = 0.028).

CONCLUSION

The use of KT reduces rates of pneumonia and pressure ulcers as compared to SC. Moreover, in this study, patients with KT had a better outcome. The study suggests that KT should be used in patients with cardiogenic shock requiring ventilator therapy for a prolonged time.

No change in the regional distribution of tidal volume during lateral posture in mechanically ventilated patients assessed by electrical impedance tomography

We assessed the distribution of regional lung ventilation during moderate and steep lateral posture using electrical impedance tomography (EIT) in mechanically ventilated patients. Seven patients were placed on a kinetic treatment table. An elastic belt containing 16 electrodes was placed around the chest and was connected to the EIT device. Patients were moved to left and right lateral positions in a stepwise (10°) mode up to 60°. EIT images [arbitrary units (AU)] were generated and scanned for assessment of relative ventilation distribution changes [tidal volume (V_T)]. A calibration procedure of arbitrary units (AUs) versus ventilator-derived V_T performed in all patients during three predefined positions (supine, 60°-left dependent and 60°-right-dependent) showed a significant correlation between V_T in supine, left and right lateral positions with the corresponding AUs (r² = 0·356, P<0·05). Changes in V_T were calculated and compared to supine position, and specific regions of interest (ROIs) were analysed. In our study, in contrast to recent findings, a change in lateral positions did not induce a significant change in regional tidal volume distribution. In right lateral positions, a broader variation of V_T with a trend towards an increase in the dependently positioned lung was observed in comparison with supine. Lateral positioning promotes the redistribution of ventilation to the ventral regions of the lung. The use of EIT technology might become a helpful tool for understanding and guiding posture therapy in mechanically ventilated patients.

Prone positioning in hypoxemic respiratory failure: meta-analysis of randomized controlled trials

PURPOSE

Prone positioning is used to improve oxygenation in patients with hypoxemic respiratory failure (HRF). However, its role in clinical practice is not yet clearly defined. The aim of this meta-analysis was to assess the effect of prone positioning on relevant clinical outcomes, such as intensive care unit (ICU) and hospital mortality, days of mechanical ventilation, length of stay, incidence of ventilator-associated pneumonia (VAP) and pneumothorax, and associated complications.

METHODS

We used literature search of MEDLINE, Current Contents, and Cochrane Central Register of Controlled Trials. We focused only on randomized controlled trials reporting clinical outcomes in adult patients with HRF. Four trials met our inclusion criteria, including 662 patients randomized to prone ventilation and 609 patients to supine ventilation.

RESULTS

The pooled odds ratio (OR) for the ICU mortality in the intention-to-treat analysis was 0.97 (95% confidence interval [CI], 0.77-1.22), for the comparison between prone and supine ventilated patients. Interestingly, the pooled OR for the ICU mortality in the selected group of the more severely ill patients favored prone positioning (OR, 0.34; 95% CI, 0.18-0.66). The duration of mechanical ventilation and the incidence of pneumothorax were not different between the 2 groups. The incidence of VAP was lower but not statistically significant in patients treated with prone positioning (OR, 0.81; 95% CI, 0.61-1.10). However, prone positioning was associated with a higher risk of pressure sores (OR, 1.49; 95% CI, 1.17-1.89) and a trend for more complications related to the endotracheal tube (OR, 1.30; 95% CI, 0.94-1.80).

CONCLUSIONS

Despite the inherent limitations of the meta-analytic approach, it seems that prone positioning has no discernible effect on mortality in patients with HRF. It may decrease the incidence of VAP at the expense of more pressure sores and complications related to the endotracheal tube. However, a subgroup of the most severely ill patients may benefit most from this intervention.

Pumpless extracorporeal interventional lung assist in patients with acute respiratory distress syndrome: a prospective pilot study

Introduction

Pumpless interventional lung assist (iLA) is used in patients with acute respiratory distress syndrome (ARDS) aimed at improving extracorporeal gas exchange with a membrane integrated in a passive arteriovenous shunt. In previous studies, feasibility and safety of the iLA system was demonstrated, but no survival benefit was observed. In the present pilot study we tested the hypothesis that timely initiation of iLA using clear algorithms and an improved cannulation technique will positively influence complication rates and management of lung protective ventilation.

Methods

iLA was implemented in 51 patients from multiple aetiologies meeting ARDS-criteria (American-European Consensus) for more than 12 hours. Initiation of iLA followed an algorithm for screening, careful evaluation and insertion technique. Patients with cardiac insufficiency or severe peripheral vascular disease were not considered suitable for iLA. Arterial and venous cannulae were inserted using a new strategy (ultrasound evaluation of vessels by an experienced team, using cannulae of reduced diameter). The incidence of complications and the effects on tidal volumes and inspiratory plateau pressures were primary outcome parameters, while oxygenation improvement and carbon dioxide removal capabilities were secondary study parameters.

Results

Initiation of iLA resulted in a marked removal in arterial carbon dioxide allowing a rapid reduction in tidal volume (≤ 6 ml/kg) and inspiratory plateau pressure. Adverse events occurred in 6 patients (11.9%). The hospital mortality rate was 49%.

Conclusions

The use of an indication algorithm for iLA in early ARDS, combined with a refined application technique was associated with efficient carbon dioxide removal and a reduced incidence of adverse events. iLA could serve as an extracorporeal assist to support mechanical ventilation by enabling low tidal volume and a reduced inspiratory plateau pressure.

Nonventilatory interventions in the acute respiratory distress syndrome

Acute respiratory distress syndrome was first described in 1967. Acute respiratory distress syndrome and acute lung injury are diseases the busy intensivist treats almost daily. The etiologies of acute respiratory distress syndrome are many. A significant distinction is based on whether the insult to the lung was direct, such as in pneumonia, or indirect, such as trauma or sepsis. Strategies for managing patients with acute respiratory distress syndrome/acute lung injury can be subdivided into 2 large groups, those based in manipulation of mechanical ventilation and those based in nonventilatory modalities. This review focuses on the nonventlilatory strategies and includes fluid restriction, exogenous surfactant, inhaled nitric oxide, manipulation of production, or administration of eicosanoids, neuromuscular blocking agents, prone position ventilation, glucocorticoids, extracorporeal membrane oxygenation, and administration of beta-agonists. Most of these therapies either have not been studied in large trials or have failed to show a benefit in terms of long-term patient mortality. Many of these therapies have shown promise in terms of improved oxygenation and may therefore be beneficial as rescue therapy for severely hypoxic patients. Recommendations regarding the use of each of these strategies are made, and an algorithm for implementing these strategies is suggested.

Pulmonary contusions and critical care management in thoracic trauma

Many victims of thoracic trauma require ICU care and mechanical ventilatory support. Pressure and volume-limited modes assist in the prevention of ventilator-associated lung injury. Ventilator-associated pneumonia is a significant cause of posttraumatic morbidity and mortality. Minimizing ventilator days, secretion control, early nutritional support, and patient positioning are methods to reduce the risk of pneumonia.

[Positioning therapy in intensive care medicine in Germany. Results of a national survey]

BACKGROUND

The effects of a systematic change in a patient's position [prone position, continuous lateral rotational therapy (CLRT)] have been investigated in recent years in acute lung injury and have shown an improvement in oxygenation, but controversial results regarding duration of mechanical ventilation, intensive care treatment and mortality compared to conventionally treated patients. We were interested in the practice and acceptance of positioning therapy in German intensive care units (ICU) and performed a national postal survey with respect to evaluation of indications, preference of particular positions, observed complications and additional aspects (costs, influence on other intensive care measures etc.).

METHODS

A questionnaire (12 multiple choice items) was sent to 1,763 ICUs, which were identified from the "Deutsches Krankenhausadressbuch" (German hospital address book 2005). The analysis was performed anonymously.

RESULTS

A total of 702 questionnaires (40.4%) were returned and analysed. The 135 degrees position (incomplete prone position) was most frequently used (50%), while the prone position (25%) and CLRT (18%) were less frequent. The improvement in oxygenation (95%) and the prevention of ventilator-associated complications (75.7%) were important indications for positioning therapy. Results of a blood gas analysis provided the necessary criteria for determining positional therapy. Supporters of the prone position advocated lower cost and better efficacy in comparison to CLRT. The frequency of complications during positioning therapy was reported to be high: hemodynamic instability (73.6%), accidental loss of tube/catheters (50.4%) and patient intolerance (40.7%) were often observed, and complication-free positioning therapy was reported in only 8.6%.

CONCLUSIONS

The 135 degrees position (incomplete prone position) is the most frequently used positioning therapy in Germany for improvement of oxygenation in patients with acute lung injury. Prone position and CLRT are less frequently used, probably due to an increased frequency of (expected) complications. The authors assume that clear guidelines and algorithms are needed to establish a more routine, safe practical application and a reduction in the complication rate.

Prone ventilation in trauma or surgical patients with acute lung injury and adult respiratory distress syndrome: is it beneficial?

BACKGROUND

To compare the effectiveness of supine versus prone kinetic therapy in mechanically ventilated trauma and surgical patients with acute lung injury (ALI) and adult respiratory distress syndrome (ARDS).

METHODS

A retrospective review of all patients with ALI/ARDS who were placed on either a supine (roto-rest) or prone (roto-prone) oscillating bed was performed. Data obtained included age, revised trauma score (RTS), base deficit, Injury Severity Score (ISS), head Abbreviated Injury Scale score (AIS), chest (AIS), PaO2/FiO2 ratio, FiO2 requirement, central venous pressure (CVP), days on the bed, ventilator days, use of pressors, complications, mortality, and pulmonary-associated mortality. Data are expressed as mean+/-SE with significance attributed to p<0.05.

RESULTS

From March 1, 2004 through May 31, 2006, 4,507 trauma patients were admitted and 221 were identified in the trauma registry as having ALI or ARDS. Of these, 53 met inclusion criteria. Additionally, 8 general surgery patients met inclusion criteria. Of these 61 patients, 44 patients were positioned supine, 13 were placed prone, and 4 patients that were initially placed supine were changed to prone positioning. There was no difference between the groups in age, CVP, ISS, RTS, base deficit, head AIS score, chest AIS score, abdominal AIS score, or probability of survival. The PaO2/FiO2 ratios were not different at study entry (149 vs. 153, p=NS), and both groups showed improvement in PaO2/FiO2 ratios. However, the prone group had better PaO2/FiO2 ratios than the supine group by day 5 (243 vs. 200, p=0.066). The prone group had fewer days on the ventilator (13.6 vs. 24.2, p=0.12), and shorter hospital lengths of stay (22 days vs. 40 days, p=0.08). There were four patients who failed to improve with supine kinetic therapy that were changed to prone kinetic therapy. These patients had significant improvements in PaO2/FiO2 ratio, and significantly lower FiO2 requirements. There were 18 deaths (7 pulmonary related) in the supine group and 1 death in the prone group (p < 0.01 by chi test).

CONCLUSIONS

ALI/ARDS patients who received prone kinetic therapy had greater improvement in PaO2/FiO2 ratio, lower mortality, and less pulmonary-related mortality than did supine positioned patients. The use of a prone-oscillating bed appears advantageous for trauma and surgical patients with ALI/ARDS and a prospective, randomized trial is warranted.

[Pulmonary pseudocysts. A rare entity after thoracic injury]

Post-traumatic pulmonary pseudocyst is a rare manifestation of blunt thoracic injury. Young adults and adolescents are predominantly affected. Here we report the successful outcome of post-traumatic pseudocysts secondary to severe lung contusion with severe intrathoracic haemorrhage in both lower lobes and the upper right lobe by aggressive coagulation management, kinetic therapy/postural drainage and control of secondary infection.

Biomechanical Analysis of Cervical and Thoracolumbar Spine Motion in Intact and Partially and Completely Unstable Cadaver Spine Models With Kinetic Bed Therapy or Traditional Log Roll

BACKGROUND

The main comorbidities associated with spinal cord injury patients are secondary to immobilization. Kinetic bed therapy is used currently to reduce the complications associated with immobilization, but the effect on the unstable spine has not been quantified. The purpose of this study was to compare the motion in the cervical and thoracolumbar spine when cadavers with spinal instabilities are log rolled (LR) on a standard hospital bed or rotated on a RotoRest kinetic treatment table (KTT).

METHODS

Cervical and lumbar instabilities were created surgically in three embalmed cadavers. An electromagnetic tracking device was used to measure the three-dimensional segmental motion generated at C5 to C6 and T12 to L2 during LR and KTT treatments.

RESULTS

In both the cervical and lumbar spine, significantly more motion was observed during LR than KTT treatment.

CONCLUSIONS

We found that in cadavers with severely unstable cervical spine, rotation using a KTT produced less flexion and lateral bending than the LR. Also, in cadavers with severely unstable lumbar spine, treatment with the KTT produced less axial rotation than the LR. Currently, we think that the best way to immobilize the spine while still allowing therapeutic motion is through the use of a KTT.

Prolonged lateral steep position impairs respiratory mechanics during continuous lateral rotation therapy in respiratory failure

OBJECTIVE

To establish whether prolonged lateral steep position during continuous rotation therapy leads to improvement on pulmonary gas exchange, respiratory mechanics and hemodynamics.

DESIGN

Prospective observational study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Twelve consecutive patients suffering from acute lung injury or adult respiratory distress syndrome undergoing continuous rotation therapy.

INTERVENTIONS

Blood gas analysis, static lung compliance, blood pressure, cardiac index and pulmonary shunt fraction were measured in supine as well as in left and right lateral steep position at 62 degrees during continuous rotation therapy (phase I). Rotation was then stopped for 30 min with the patients in supine position, left and right lateral steep position, and the same measurements were performed every 10 min (phase II).

MEASUREMENTS AND RESULTS

Phase I and II revealed no significant changes in PaO(2)/FiO(2) ratio, mean arterial blood pressure, pulmonary shunt fraction, or cardiac index. Significantly lower static compliance was observed in lateral steep position than in supine position (p<0.001). Concomitantly, PaCO(2) was significantly lower in supine position than in left and right lateral steep position (p<0.01).

CONCLUSIONS

Lateral steep positioning impairs the compliance of the respiratory system. Prolonged lateral steep position does not lead to benefits with respect to oxygenation or hemodynamics. Individual response to the different positions is unpredictable. The pauses in "extreme" positions should be as short as possible.

Rotational Bed Therapy to Prevent and Treat Respiratory Complications: A Review and Meta-Analysis

• Background Immobility is associated with complications involving many body systems.

• Objective To review the effect of rotational therapy (use of therapeutic surfaces that turn on their longitudinal axes) on prevention and/or treatment of respiratory complications in critically ill patients.

• Methods Published articles evaluating prophylaxis and/or treatment were reviewed. Prospective randomized controlled trials were assessed for quality and included in meta-analyses.

• Results A literature search yielded 15 nonrandomized, uncontrolled, or retrospective studies. Twenty prospective randomized controlled trials on rotational therapy were published between 1987 and 2004. Various types of beds were studied, but few details on the rotational parameters were reported. The usual control was manual turning of patients by nurses every 2 hours. One animal investigation and 12 clinical trials addressed the effectiveness of rotational therapy in preventing respiratory complications. Significant benefits were reported in the animal study and 4 of the trials. Significant benefits to patients were reported in 2 of another 4 studies focused on treatment of established complications. Researchers have examined the effects of rotational therapy on mucus transport, intrapulmonary shunt, hemodynamic effects, urine output, and intracranial pressure. Little convincing evidence is available, however, on the most effective rotation parameters (eg, degree, pause time, and amount of time per day). Meta-analysis suggests that rotational therapy decreases the incidence of pneumonia but has no effect on duration of mechanical ventilation, number of days in intensive care, or hospital mortality.

• Conclusions Rotational therapy may be useful for preventing and treating respiratory complications in selected critically ill patients receiving mechanical ventilation.

Alveolar recruitment during prone position: time matters

Alveolar recruitment is one of the beneficial effects of prone positioning in patients with ARDS (acute respiratory distress syndrome). However, responses vary among patients and, therefore, we hypothesized that alveolar recruitment is an individual time-dependent process and its measurement might be helpful to 'dose' prone positioning individually. In 13 patients diagnosed with ARDS, EELV (end-expiratory lung volume) was measured in the supine position, immediately after turning to the prone position, at 1, 2, 4 and 8 h in the prone position and after returning to the supine position. Responders were defined based on a 30% increase in oxygenation. EELV increased in responders, whereas it remained constant in non-responders. The time course was different in individual patients. In some responders, a plateau was reached as early as 2-4 h, whereas, in others, 8 h of prone positioning was not sufficient to allow complete recruitment. The increase in lung volume was associated with both an increase in arterial oxygenation and a decrease in venous admixture. Furthermore, responders had significantly lower baseline EELVs than non-responders. In conclusion, alveolar recruitment during prone positioning has been characterized as an individual time-dependent process. Its measurement might be useful to apply prone positioning more individually and might also help to identify responders.

Ventilatory strategies and adjunctive therapy in ARDS

Acute respiratory distress syndrome, a diagnosis based on physiologic and radiological criteria, occurs commonly in critical care setting. A major challenge in evaluating therapies that may improve survival in ARDS is that it is not a single disease entity but, rather, numerous different diseases that result in endothelial injury, where the most obvious manifestation is within the lung resulting in pulmonary oedema. It has been shown that poor ventilatory technique that is injurious to the lungs can propagate systemic inflammatory response and adversely affect the mortality. The current data suggest that high tidal volumes with high plateau pressures are deleterious and a strategy of ventilation with lower tidal volumes and lower plateau pressure is associated with lower mortality. There may be a role for recruitment manoeuvres as well. Other forms of respiratory support still require further research. The present understanding of optimal ventilatory management and other adjunctive therapies are reviewed.

Kinetic therapy reduces complications and shortens hospital stay in patients with cardiogenic shock - a retrospective analysis

BACKGROUND

Kinetic therapy (KT) has been shown to reduce complications and to shorten hospital stay in trauma patients. Data in non-surgical patients are inconclusive, and kinetic therapy has not been tested in patients with cardiogenic shock.

OBJECTIVE

The present analysis compares KT with standard care in patients with cardiogenic shock.

METHODS

A retrospective analysis of 133 patients with cardiogenic shock admitted to 1 academic heart center was performed. Patients with standard care (SC, turning every 2 h by the staff) were compared with kinetic therapy (KT, using oscillating air-flotation beds).

MEASUREMENTS AND MAIN RESULTS

68 patients with KT were compared with 65 patients with SC. Length of ventilator therapy was 11 days in KT and 18 days in SC (p=0.048). The mortality was comparable in both groups. Pneumonia occurred in 14 patients in KT and 39 patients in SC (p<0.001); pressure ulcers were reduced by 50% (p<0.001). Length of ICU stay (21 days in SC and 13 days in KT, p=0.009) and length of hospital stay were reduced in the patients treated with kinetic therapy.

CONCLUSION

The use of KT shortens hospital stay and reduces rates of pneumonia and pressure ulcers as compared to SC.

Body positioning and its effect on oxygenation--a literature review

Evidence-based health care has become a priority in the National Health Service (NHS), with increased emphasis on clinical practices that are grounded in quality evidence rather than those that persist because of tradition. Turning and positioning of patients are well-accepted nursing activities. Appropriate positioning of the critically ill patient can dramatically improve gas exchange, resulting in a shorter stay in the critical care unit and an improved outcome. This study reviews the current published literature on the subject of positioning and gas exchange, with emphasis on oxygenation. Conclusions made from this study are that nurses need to be aware of how different positions can affect patients' oxygenation. Further research on exploring patients' experience of positioning within the critical care environment and nurses' understanding of positioning and oxygenation is needed.

Kinetic therapy improves oxygenation in critically ill pediatric patients

OBJECTIVE

To compare changes in oxygenation after manual turning and percussion (standard therapy) and after automated rotation and percussion (kinetic therapy).

DESIGN

Randomized crossover trial.

SETTING

General and cardiac pediatric intensive care units.

PATIENTS

Intubated and mechanically ventilated pediatric patients who had an arterial catheter and no contraindications to using a PediDyne bed.

INTERVENTIONS

Patients were placed on a PediDyne bed (Kinetic Concepts) and received 18 hrs blocks of standard and kinetic therapy in an order determined by randomization.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gases were measured every 2 hrs during each phase of therapy. Oxygenation index and arterial-alveolar oxygen tension difference [P(A-a)O(2)] were calculated. Indexes calculated at baseline and after each 18-hr phase of therapy were analyzed. Fifty patients were enrolled. Data from 15 patients were either not collected or not used due to reasons that included violation of protocol and inability to tolerate the therapies in the study. Indexes of oxygenation were not normally distributed and were compared using Wilcoxon signed rank testing. Both therapies led to improvements in oxygenation, but only those from kinetic therapy achieved statistical significance. In patients receiving kinetic therapy first, median oxygenation index decreased from 7.4 to 6.19 (p = .015). The median P(A-a)O(2) decreased from 165.2 to 126.4 (p = .023). There were continued improvements in oxygenation after the subsequent period of standard therapy, with the median oxygenation index decreasing to 5.52 and median P(A-a)O(2) decreasing to 116.0, but these changes were not significant (p = .365 and .121, respectively). When standard therapy was first, the median oxygenation index decreased from 8.83 to 8.71 and the median P(a-a)o(2) decreased from 195.4 to 186.6. Neither change was significant. Median oxygenation index after the subsequent period of kinetic therapy was significantly lower (7.91, p = .044) and median P(A-a)O(2) trended lower (143.4, p = .077).

CONCLUSIONS

Kinetic therapy is more efficient than standard therapy at improving oxygenation and produces improvements in oxygenation that are more persistent.

Acute effects of upright position on gas exchange in patients with acute respiratory distress syndrome

Patients with acute respiratory distress syndrome (ARDS) have dorsal atelectasis of the lungs. This is probably caused by several mechanisms: compression on dependent lung zones, purulent secretions in alveoli, and upward shift of the diaphragm. An upright position (UP) of the patient (the whole body in a straight line at 40 to 45 degrees) can theoretically ameliorate these mechanisms. The objective was to evaluate whether there was an improvement of gas exchange during UP of ARDS patients and to evaluate the hemodynamic effects. A prospective interventional study was performed in the surgical and medical ICUs and the burn unit of the Ghent University Hospital, a tertiary care center. Included were ARDS patients with onset of ARDS within 48 hours before start of the study. Patients were excluded when there was hemodynamic instability or when the PaO2/FiO2 ratio deteriorated during the 2 hours preceding UP. After a 2-hour observation period in a semirecumbent position, patients were put in UP for 12 hours. Respiration and hemodynamic data were recorded at the start and end of the 2-hour observation period, and after 1, 4, and 12 hours in UP. Eighteen patients were included in the study. There was a significant increase of the PaO2/FiO2 ratio during UP (P < .001). Except for the need for volume resuscitation in 5 patients (27.8%), there was no significant change in the hemodynamic profile of the patients. Upright positioning of patients with ARDS, a relatively simple maneuver, resulted in an improvement of gas exchange and was tolerated hemodynamically relatively well during a 12-hour observation period.

Kinetic therapy positively influences oxygenation in patients with ALI/ARDS

Acute respiratory distress syndrome (ARDS) is a fulminant form of respiratory failure, with diverse aetiology, despite technological advances in intensive care medicine; mortality rates remain 50-70%. Costs associated with the management of patients in intensive therapy unit (ITU) are very high; therefore, the requirement for those working in critical care to provide evidence-based practice is mandatory. One area of investigation is that kinetic therapy improves pulmonary complications in critically ill patients by positively influencing oxygenation and gaseous exchange. Whilst kinetic therapy does appear to be an effective therapy in ITU, there are inconsistencies in reported findings, and thus, clearly a need for further research into this innovative therapy to maximize its potential.

Rotación continua lateralizada o terapia cinética: una actualización de conocimientos

Acute lung injury and, when extreme, acute respiratory distress syndrome, are thought to be expression of a diffuse and overwhelming inflammatory reaction of the pulmonary capillary membrane to a variety of causes. The ventilatory support is essential in this patients. In the last years we know the significance of the postural treatment in this type of patients through the prone positioning. The continuous lateral rotation therapy or kinetic therapy (KT) is the new manner by other positioning beside the technological advances. Lowly it's introducing in our setting. The follow article would respound the next questions: What's the KT? How must to make the KT? What recommendations have been offered by specialists from the complications? Which is it efectivity?

Methods to prevent ventilator-associated lung injury: a summary

Mechanical ventilation can cause ventilator-associated lung injury (VALI). This may manifest itself in various forms such as pneumothorax or, at the most extreme level, multi-system organ failure. The exact mechanisms by which the injury occurs are not known but appear to involve the conversion of mechanical stimulation of alveolar membranes into intracellular signalling, with subsequent upregulation of inflammatory mediators that produce the damage. This has been termed biotrauma. Furthermore, disruption of alveolar-capillary membranes may allow the release of these mediators into the systemic circulation that underpins the systemic inflammatory response syndrome. Various protective ventilatory strategies may be employed in order to reduce the lung damage and shall be discussed in this paper.

Prone positioning in the patient who has acute respiratory distress syndrome: the art and science

Acute respiratory distress syndrome (ARDS) remains a significant contributor to the morbidity and mortality of patients in the ICU. A variety of treatments are used to support the lung of the patient who has ARDS and improve gas exchange during the acute injury phase. It seems, however, that the simple, safe, and noninvasive act of prone positioning of the critically ill patient who has ARDS may improve gas exchange while preventing potential complications of high positive end-expiratory pressure, volutrauma, and oxygen toxicity. This article provides the critical care nurse with the physiologic rationale for use of the prone position, indications and contraindications for use, safe strategies for prone positioning, and care techniques and monitoring methods of the patient who is in the prone position.

The pragmatics of feeding the pediatric patient with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents the ultimate pulmonary response to a wide range of injuries, from septicemia to trauma. Optimal nutrition is vital to enhancing oxygen delivery, supporting adequate cardiac contractility and respiratory musculature, eliminating fluid and electrolyte imbalances, and supporting the proinflammatory response. Research is providing a better understanding of nutrients that specifically address the complex physiologic changes in ARDS. This article highlights the pathophysiology of ARDS as it relates to nutrition, relevant nutritional assessment, and important enteral and parenteral considerations for the pediatric patient who has ARDS.

Approaches in the management of acute respiratory failure in children

PURPOSE OF REVIEW

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are conditions that are associated with significant morbidity and mortality in children. There have been no advances in preventing ARDS, but this review highlights strategies directed at minimizing ventilator-induced lung injury and other new adjunctive therapies in the care of these patients.

RECENT FINDINGS

High-frequency oscillatory ventilation, airway pressure release ventilation, and partial liquid ventilation are potential protective ventilatory modes for children with ALI or ARDS. Recruitment maneuvers, prone positioning, and kinetic therapy are all reported to improve oxygenation by opening the lung while positive end-expiratory pressure maintains functional residual capacity. Inhaled nitric oxide and surfactant are used to reduce inspired oxygen concentration and facilitate gas exchange, but their efficacy in ARDS continues to be investigated. Also, early investigations suggest that a specialized enteral formula can be a useful adjunctive therapy by reducing lung inflammation and improving oxygenation. When mechanical ventilation and adjunctive therapies fail, extracorporeal life support continues to be used as a rescue therapy.

SUMMARY

It is likely that a combination of these therapies will maximize treatment and clinical outcomes in the future, but the only way that will be proven is through large controlled clinical trials in pediatric patients.

Inhaled nitric oxide for acute hypoxic respiratory failure in children and adults: a meta-analysis

We systematically reviewed randomized controlled trials examining inhaled nitric oxide (INO) for the treatment of acute respiratory distress syndrome or acute lung injury in children and adults. Qualitative assessments of identified trials were made, and metaanalyses were performed according to Cochrane methodology. Five randomized controlled trials (n = 535) met entry criteria. One study demonstrated significant improvement in oxygenation in the first 4 days of treatment, with no difference after this. There was no difference in ventilator-free days between treatment and placebo groups, and no specific dose of INO was more advantageous than any other. INO had no effect on mortality in trials without crossover of treatment failures to open-label INO (relative risk, 0.98; 95% confidence interval, 0.66-1.44). Other clinical indicators of effectiveness, such as duration of hospital and intensive care stay, were inconsistently reported. Lack of data prevented assessment of all outcomes. If further trials assessing INO in acute respiratory distress syndrome or acute lung injury are to proceed, they should be stratified for primary etiology, incorporate other modalities that may affect outcome, and evaluate clinically relevant outcomes before any benefit of INO can be excluded.

Unilateral lung injury

Mechanical ventilation is a supportive lifesaving therapy that can potentially cause lung injury if periodic alveolar overdistension, or cyclic collapse, and reopening occur. The use of a low tidal volume with moderate to high positive end-expiratory pressure improves the survival of patients with acute lung injury and acute respiratory distress syndrome. Positioning the patient with the "good lung down" and using differential ventilation with selective positive end-expiratory pressure are the two currently accepted ventilatory strategies to be applied in patients with severe unilateral lung injury. However, both have serious limitations in clinical practice. Lung injury may be rather inhomogeneous-confined to one lung or preferentially distributed toward the dependent lung areas. In unilateral lung injury, ventilatory strategies that allow recruitment of injured lung and that avoid overdistension of uninjured lung parenchyma should be applied. Experimental studies have shown that the use of selective tracheal gas insufflation and partial liquid ventilation facilitates low tidal volume with appropriate gas exchange while reducing cyclic lung stretch and shear stresses. Further studies are needed to determine future applications of these therapies in humans.

Gas exchange in the ventilated patient

Increased knowledge of the pathophysiologic mechanisms of impaired gas exchange during acute respiratory failure during recent years has stimulated many studies that evaluate different treatments to improve oxygenation and outcome. Changes in body position (mainly prone positioning) can significantly improve gas exchange in patients with acute respiratory distress syndrome and acute lung failure, with few complications related to the maneuver; however, no survival advantage has yet been detected. A correlation between aerated lung tissue and oxygenation also confirms the importance of recruitment maneuvers in improving gas exchange. Recent suggestions that recruitment of alveoli proceeds during most of the inspired vital capacity and not only around the lower inflection point of the pressure-volume curve raises the question how to best perform recruitment maneuvers. New data support the hypothesis that maintenance of even small amount of spontaneous breathing during mechanical ventilation (with airway pressure release ventilation or biphasic positive airway pressure) can improve gas exchange, whereas other unconventional ventilatory modes have not yet proved advantageous. Some mechanisms responsible for the high percentage of nonresponse to inhaled nitric oxide have recently been proposed, and combinations of inhaled nitric oxide with other therapies have been tested. Increased knowledge in this area may, in the future, make inhaled nitric oxide more attractive in the treatment of adult respiratory failure as well as in neonatal intensive care.