Effect of air-supported, continuous, postural oscillation on the risk of early ICU pneumonia in nontraumatic critical illness

Inapparent Outbreaks of Ventilator-Associated Pneumonia An Ecologic Analysis of Prevention and Cohort Studies

Objective:

To compare ventilator-associated pneumonia (VAP) rates and patterns of isolates across studies of antibiotic and non-antibiotic methods for preventing VAP.

Design:

With the use of 42 cohort study groups as the reference standard, the prevalence of VAP was modeled in two linear regressions: one with the control groups and the other with the intervention groups of 96 VAP prevention studies. The proportion of patients admitted with trauma and the VAP diagnostic criteria were used as ecologic correlates. Also, the patterns of pathogenic isolates were available for 117 groups.

Results:

In the first regression model, the VAP rates for the control groups of antibiotic-based prevention studies were at least 18 (CI95, 12 to 24) per 100 patients higher than those in the cohort study groups (P< .001). By contrast, comparisons of cohort study groups with all other control and intervention groups in the first and second regression models yielded differences that were less than 6 per 100 and not significant (P> .05). For control groups with VAP rates greater than 35%, the patterns of VAP isolates, such as the proportion ofStaphylococcus aureus,more closely resembled those in the corresponding intervention groups than in the cohort groups.

Conclusions:

The rates of VAP in the control groups of the antibiotic prevention studies were significantly higher than expected and the patterns of pathogenic isolates were unusual. These observations suggest that inapparent outbreaks of VAP occurred in these studies. The possibility remains that antibiotic-based VAP prevention presents a major cross-infection hazard.

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.

Support surfaces for pressure ulcer prevention

BACKGROUND

Pressure ulcers (i.e. bedsores, pressure sores, pressure injuries, decubitus ulcers) are areas of localised damage to the skin and underlying tissue. They are common in the elderly and immobile, and costly in financial and human terms. Pressure-relieving support surfaces (i.e. beds, mattresses, seat cushions etc) are used to help prevent ulcer development.

OBJECTIVES

This systematic review seeks to establish:(1) the extent to which pressure-relieving support surfaces reduce the incidence of pressure ulcers compared with standard support surfaces, and,(2) their comparative effectiveness in ulcer prevention.

SEARCH METHODS

In April 2015, for this fourth update we searched The Cochrane Wounds Group Specialised Register (searched 15 April 2015) which includes the results of regular searches of MEDLINE, EMBASE and CINAHL and The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015, Issue 3).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised trials, published or unpublished, that assessed the effects of any support surface for prevention of pressure ulcers, in any patient group or setting which measured pressure ulcer incidence. Trials reporting only proxy outcomes (e.g. interface pressure) were excluded. Two review authors independently selected trials.

DATA COLLECTION AND ANALYSIS

Data were extracted by one review author and checked by another. Where appropriate, estimates from similar trials were pooled for meta-analysis.

MAIN RESULTS

For this fourth update six new trials were included, bringing the total of included trials to 59.Foam alternatives to standard hospital foam mattresses reduce the incidence of pressure ulcers in people at risk (RR 0.40 95% CI 0.21 to 0.74). The relative merits of alternating- and constant low-pressure devices are unclear. One high-quality trial suggested that alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context.Pressure-relieving overlays on the operating table reduce postoperative pressure ulcer incidence, although two trials indicated that foam overlays caused adverse skin changes. Meta-analysis of three trials suggest that Australian standard medical sheepskins prevent pressure ulcers (RR 0.56 95% CI 0.32 to 0.97). 

AUTHORS' CONCLUSIONS

People at high risk of developing pressure ulcers should use higher-specification foam mattresses rather than standard hospital foam mattresses. The relative merits of higher-specification constant low-pressure and alternating-pressure support surfaces for preventing pressure ulcers are unclear, but alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context. Medical grade sheepskins are associated with a decrease in pressure ulcer development. Organisations might consider the use of some forms of pressure relief for high risk patients in the operating theatre.

Infection control in the intensive care unit

Nosocomial infections are common in many hospital departments, but particularly so on the intensive care unit, where they affect some 20 to 30% of patients. While early diagnosis and appropriate treatment are, of course, important, perhaps the greatest challenge is in the application of techniques to limit the development of such infections. This review will briefly discuss some of the background pathophysiology and epidemiology of nosocomial infection, and then focus on general and infection-specific preventative strategies individually and as part of broader infection-control programs with infection surveillance.

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.

Physiotherapy in critically ill patients

Prolonged stay in Intensive Care Unit (ICU) can cause muscle weakness, physical deconditioning, recurrent symptoms, mood alterations and poor quality of life. Physiotherapy is probably the only treatment likely to increase in the short- and long-term care of the patients admitted to these units. Recovery of physical and respiratory functions, coming off mechanical ventilation, prevention of the effects of bed-rest and improvement in the health status are the clinical objectives of a physiotherapy program in medical and surgical areas. To manage these patients, integrated programs dealing with both whole-body physical therapy and pulmonary care are needed. There is still limited scientific evidence to support such a comprehensive approach to all critically ill patients; therefore we need randomised studies with solid clinical short- and long-term outcome measures.

Support surfaces for pressure ulcer prevention

BACKGROUND

Pressure ulcers (i.e. bedsores, pressure sores, decubitus ulcers) are areas of localised damage to the skin and underlying tissue. They are common in the elderly and immobile, and costly in financial and human terms. Pressure-relieving support surfaces (i.e. beds, mattresses, seat cushions etc) are used to help prevent ulcer development.

OBJECTIVES

This systematic review seeks to establish: (1) the extent to which pressure-relieving support surfaces reduce the incidence of pressure ulcers compared with standard support surfaces, and, (2) their comparative effectiveness in ulcer prevention.

SEARCH STRATEGY

For this third update we searched: the Cochrane Wounds Group Specialised Register (searched 8 December 2010), The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 4); Ovid MEDLINE (1950 to November Week 3 2010); Ovid MEDLINE (In-Process & Other Non-Indexed Citations December 07, 2010); Ovid EMBASE (1980 to 2010 Week 48); EBSCO CINAHL (1982 to 3 December 2010), and the reference sections of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised studies, published or unpublished, that assessed the effects of any support surface for prevention of pressure ulcers, in any patient group or setting which measured pressure ulcer incidence.Studies reporting only proxy outcomes (e.g. interface pressure) were excluded. Two review authors independently selected studies.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author and checked by another. Where appropriate, estimates from similar studies were pooled for meta-analysis.

MAIN RESULTS

One new trial was included, bringing the total of included studies to 53.Foam alternatives to standard hospital foam mattresses reduce the incidence of pressure ulcers in people at risk (RR 0.40 95% CI 0.21 to 0.74). The relative merits of alternating- and constant low-pressure devices are unclear. One high-quality trial suggested that alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context.Pressure-relieving overlays on the operating table reduce postoperative pressure ulcer incidence, although two studies indicated that foam overlays caused adverse skin changes. Meta-analysis of three trials indicated that Australian standard medical sheepskins prevent pressure ulcers (RR 0.56 95% CI 0.32 to 0.97). 

AUTHORS' CONCLUSIONS

People at high risk of developing pressure ulcers should use higher-specification foam mattresses rather than standard hospital foam mattresses. The relative merits of higher-specification constant low-pressure and alternating-pressure support surfaces for preventing pressure ulcers are unclear, but alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context. Medical grade sheepskins are associated with a decrease in pressure ulcer development. Organisations might consider the use of some forms of pressure relief for high risk patients in the operating theatre.

Recognition and prevention of nosocomial pneumonia in the intensive care unit and infection control in mechanical ventilation

Nosocomial pneumonia (NP) is a difficult diagnosis to establish in the critically ill patient due to the presence of underlying cardiopulmonary disorders (e.g., pulmonary contusion, acute respiratory distress syndrome, atelectasis) and the nonspecific radiographic and clinical signs associated with this infection. Additionally, the classification of NP in the intensive care unit setting has become increasingly complex, as the types of patients who develop NP become more diverse. The occurrence of NP is especially problematic as it is associated with a greater risk of hospital mortality, longer lengths of stay on mechanical ventilation and in the intensive care unit, a greater need for tracheostomy, and significantly increased medical care costs. The adverse effects of NP on healthcare outcomes has increased pressure on clinicians and healthcare systems to prevent this infection, as well as other nosocomial infections that complicate the hospital course of patients with respiratory failure. This manuscript will provide a brief overview of the current approaches for the diagnosis of NP and focus on strategies for prevention. Finally, we will provide some guidance on how standardized or protocolized care of mechanically ventilated patients can reduce the occurrence of and morbidity associated with complications like NP.

Reduction in the incidence of poststroke nosocomial pneumonia by using the "turn-mob" program

BACKGROUND

One of the most common complications in patients with acute ischemic stroke (AIS) is pneumonia, a complication that has an impact on the patient's survival. The purpose of this study was to establish whether the implementation of a passive turning and mobilization program can prevent the occurrence of nosocomial pneumonia (NP) in patients with AIS.

METHODS

We conducted a randomized clinical trial. Patients diagnosed with AIS within the last 48 hours and without mechanical ventilation were included. Group A was the "turn-mob" program: turning and passive mobilization carried out by a previously trained relative. Group B was the control group: standard treatment characterized by turning carried out by the nursing staff. The purpose was to demonstrate whether the implementation of a manual turning and passive mobilization program could reduce the incidence of NP in patients with AIS during their stay at the hospital and up to 14 days after discharge.

RESULTS

In all, 223 patients were included (group A, n = 111; group B, n = 112). Fourteen (12.6%) patients in group A and 30 (26.8%) in group B developed NP. The implementation of the turn-mob program was associated with a decrease in NP, with a relative risk of 0.39 (95% confidence interval .19-.79; P = .008).

CONCLUSION

The turn-mob program applied on patients during the acute phase of an ischemic stroke decreases the incidence of NP.

Continuous lateral rotation therapy to prevent ventilator-associated pneumonia

OBJECTIVE

To investigate the impact of prophylactic continuous lateral rotation therapy on the prevalence of ventilator-associated pneumonia, duration of mechanical ventilation, length of stay, and mortality in critically ill medical patients.

DESIGN

Prospective, randomized, clinical study.

SETTING

Three medical intensive care units of an university tertiary care hospital.

PATIENTS

Patients were randomized to continuous lateral rotation therapy or standard care if they were mechanically ventilated for <48 hrs and free from pneumonia. Primary study end point was development of ventilator-associated pneumonia. Ventilator-associated pneumonia was defined as infiltrate on the chest radiograph plus newly developed purulent tracheal secretion plus increasing signs of inflammation. The diagnosis had to be confirmed microbiologically and required the growth of a pathogen >10(4) colony-forming units/mL in bronchoalveolar lavage. Radiologists were blinded to randomization whereas clinical outcome assessors were not.

INTERVENTIONS

Rotation therapy was performed continuously in a specially designed bed over an arc of 90 degrees. Additional measures to prevent ventilator-associated pneumonia were equally standardized in both groups including semirecumbent position.

MEASUREMENTS AND MAIN RESULTS

Ventilator-associated pneumonia frequency during the intensive care unit stay was 11% in the rotation group and 23% in the control group (p = .048), respectively. Duration of ventilation (8 +/- 5 vs. 14 +/- 23 days, p = .02) and length of stay (25 +/- 22 days vs. 39 +/- 45 days, p = .01) were significantly shorter in the rotation group. In a forward stepwise logistic regression model including the continuous lateral rotation therapy, gender, Lung Injury Score, and Simplified Acute Physiology Score II, continuous lateral rotation therapy just failed to reach statistical significance with respect to development of ventilator-associated pneumonia (p = .08). Intolerance to continuous lateral rotation therapy during the weaning phase was observed in 29 patients (39%). Mortality was comparable in both groups.

CONCLUSIONS

Ventilator-associated pneumonia prevalence was significantly reduced by continuous lateral rotation therapy. Continuous lateral rotation therapy led to shorter ventilation time and length of stay. Continuous lateral rotation therapy should be considered in ventilated patients at risk for ventilator-associated pneumonia as a feasible method exerting additive effects to other preventive measures.

Continuous lateral rotation therapy for acute hypoxemic respiratory failure: the effect of timing

Previous studies have indicated a positive impact of continuous lateral rotational therapy on nosocomial pneumonia, but have shown mixed results in decreasing length of stay or ventilator days. The objective of the study was to determine if the use of a continuous lateral rotational therapy protocol would decrease mortality and morbidity, mean ventilator days, and/or intensive care unit and hospital length of stay in patients with a pulmonary diagnosis. The study also analyzed the effect of the lag time to the initiation of therapy. Prospectively enrolled subjects receiving continuous lateral rotational therapy based on predetermined indications were compared with retrospectively identified control subjects who met the same inclusion criteria from a similar time period in the previous year. Early initiation of continuous lateral rotational therapy resulted in significant decreases in ventilator days and intensive care unit length of stay. The therapeutic benefit of continuous lateral rotational therapy may be enhanced with early identification and treatment of appropriate patients.

Physiological rationale and current evidence for therapeutic positioning of critically ill patients

Prolonged bed rest is common in critically ill patients, and therapeutic positioning is important to prevent further complications and to improve patient outcomes. Nurses use therapeutic positioning to prevent complications of immobility. This article reviews therapeutic positions including stationary positions (supine, semirecumbent with head of bed elevation, lateral, and prone) and active repositioning (manual, continuous lateral rotation, and kinetic therapy). The physiological rationale and current evidence for each position are described. Applicable evidence-based practice guidelines are summarized. Special considerations for therapeutic positioning of critically ill obese and elderly patients are also discussed.

Support surfaces for pressure ulcer prevention

BACKGROUND

Pressure ulcers (also known as bedsores, pressure sores, decubitus ulcers) are areas of localised damage to the skin and underlying tissue due to pressure, shear or friction. They are common in the elderly and immobile and costly in financial and human terms. Pressure-relieving beds, mattresses and seat cushions are widely used as aids to prevention in both institutional and non-institutional settings.

OBJECTIVES

This systematic review seeks to answer the following questions:(1) to what extent do pressure-relieving cushions, beds, mattress overlays and mattress replacements reduce the incidence of pressure ulcers compared with standard support surfaces?(2) how effective are different pressure-relieving surfaces in preventing pressure ulcers, compared to one another?

SEARCH STRATEGY

For this second update the Cochrane Wounds Group Specialised Register was searched (28/2/08), The Cochrane Central Register of Controlled Trials (CENTRAL)(2008 Issue 1), Ovid MEDLINE (1950 to February Week 3 2008), Ovid EMBASE (1980 to 2008 Week 08) and Ovid CINAHL (1982 to February Week 3 2008). The reference sections of included studies were searched for further trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs), published or unpublished, which assessed the effectiveness of beds, mattresses, mattress overlays, and seating cushions for the prevention of pressure ulcers, in any patient group, in any setting. Study selection was undertaken by at least two authors independently with a third author resolving uncertainty. RCTs were eligible for inclusion if they reported an objective, clinical outcome measure such as incidence and severity of new of pressure ulcers developed. Studies which only reported proxy outcome measures such as interface pressure were excluded.

DATA COLLECTION AND ANALYSIS

Trial data were extracted by one researcher and checked by a second. The results from each study are presented as relative risk for dichotomous variables. Where deemed appropriate, similar studies were pooled in a meta analysis.

MAIN RESULTS

For this second update 11 trials met the inclusion criteria bringing the total number of RCTs included in the review to 52.Foam alternatives to the standard hospital foam mattress can reduce the incidence of pressure ulcers in people at risk. The relative merits of alternating and constant low pressure devices are unclear. There is one high quality trial comparing the different alternating pressure devices for pressure ulcer prevention which suggests that alternating pressure mattresses may be more cost effective than alternating pressure overlays.Pressure-relieving overlays on the operating table have been shown to reduce postoperative pressure ulcer incidence, although two studies indicated that foam overlays resulted in adverse skin changes. Two trials indicated that Australian standard medical sheepskins prevented pressure ulcers. There is insufficient evidence to draw conclusions on the value of seat cushions, limb protectors and various constant low pressure devices as pressure ulcer prevention strategies.A study of Accident & Emergency trolley overlays did not identify a reduction in pressure ulcer incidence. There are tentative indications that foot waffle heel elevators, a particular low air loss hydrotherapy mattress and two types of operating theatre overlays are harmful.

AUTHORS' CONCLUSIONS

In people at high risk of pressure ulcer development higher specification foam mattresses rather than standard hospital foam mattresses should be used. The relative merits of higher-tech constant low pressure and alternating pressure for prevention are unclear but alternating pressure mattresses may be more cost effective than alternating pressure overlays. Medical grade sheepskins are associated with a decrease in pressure ulcer development. Organisations might consider the use of some forms of pressure relief for high risk patients in the operating theatre. Seat cushions and overlays designed for use in Accident & Emergency settings have not been adequately evaluated.

Clinical review: airway hygiene in the intensive care unit

Maintenance of airway secretion clearance, or airway hygiene, is important for the preservation of airway patency and the prevention of respiratory tract infection. Impaired airway clearance often prompts admission to the intensive care unit (ICU) and can be a cause and/or contributor to acute respiratory failure. Physical methods to augment airway clearance are often used in the ICU but few are substantiated by clinical data. This review focuses on the impact of oral hygiene, tracheal suctioning, bronchoscopy, mucus-controlling agents, and kinetic therapy on the incidence of hospital-acquired respiratory infections, length of stay in the hospital and the ICU, and mortality in critically ill patients. Available data are distilled into recommendations for the maintenance of airway hygiene in ICU patients.

Is there evidence to support the use of lateral positioning in intensive care? A systematic review

A systematic review of randomised clinical trials was conducted to investigate the efficacy and safety of use of the lateral position in the management of ventilated intensive care patients. One review article and 11 empiric studies, which were mostly of low methodological quality, met the eligibility criteria. Large individual variations in PaO2 response to lateral positioning were demonstrated. Greatest improvement in PaO2 occurred in patients with unilateralpulmonary infiltrates positioned with the bad lung up versus bad lung down (average difference = 33.6 mmHg (range 0-58), effect size 1.13 (95% CI: 0.44, 1.19, P = 0.001)) or supine (average difference=27 mmHg (range 5-42), effect size 0.58 (95% CI: 0.11, 1.06, P = 0.017)). This effect appeared to be most prominent in patients with widespread, unilateral infiltrates. Lung compliance was not affected by lateral positioning. Haemodynamic compromise was evident with lateral positioning of greater than 60 degrees to the right side in patients requiring vasopressors and/or with right ventricular dysfunction; or with lateral positioning in postoperative coronary artery bypass graft patients. No studies were found that had investigated the effect of routine applications of the lateral positioning to improve, prevent or treat pneumonia, decrease mortality or influence other long-term outcomes. The results of this review demonstrate the limited evidence available to support the use of lateral positioning in the intensive care environment. More data reporting the long-term effects of lateral position on long-term outcomes would aid clinical decision making and may improve the application of patient positioning in critical care environments.

Ventilator-associated pneumonia and pressure ulcer prevention as targets for quality improvement in the ICU

The health care culture must change. Florence Nightingale wrote [8] "deep-rooted and universal is the conviction that to give a medicine is to be doing something, or rather everything and to give air, warmth, cleanliness etc. is to do nothing." Hygiene care practices and mobility activities are fundamental and independent care components in the nursing profession. When implemented using available evidence, they can significantly improve patient outcomes. It is time to claim and demonstrate the importance of consistent delivery of the fundamentals of basic nursing care. Interventional patient hygiene is an effective framework to ensure the the basics of nursing care are consistently applied to improve patient outcomes.

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.

Ventilator-associated pneumonia: diagnosis, treatment, and prevention

While critically ill patients experience a life-threatening illness, they commonly contract ventilator-associated pneumonia. This nosocomial infection increases morbidity and likely mortality as well as the cost of health care. This article reviews the literature with regard to diagnosis, treatment, and prevention. It provides conclusions that can be implemented in practice as well as an algorithm for the bedside clinician and also focuses on the controversies with regard to diagnostic tools and approaches, treatment plans, and prevention strategies.

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.

Kinetic bed therapy to prevent nosocomial pneumonia in mechanically ventilated patients: a systematic review and meta-analysis

INTRODUCTION

Nosocomial pneumonia is the most important infectious complication in patients admitted to intensive care units. Kinetic bed therapy may reduce the incidence of nosocomial pneumonia in mechanically ventilated patients. The objective of this study was to investigate whether kinetic bed therapy reduces the incidence of nosocomial pneumonia and improves outcomes in critically ill mechanically ventilated patients.

METHODS

We searched Medline, EMBASE, CINAHL, CENTRAL, and AMED for studies, as well as reviewed abstracts of conference proceedings, bibliographies of included studies and review articles and contacted the manufacturers of medical beds. Studies included were randomized or pseudo-randomized clinical trials of kinetic bed therapy compared to standard manual turning in critically ill mechanically ventilated adult patients. Two reviewers independently applied the study selection criteria and extracted data regarding study validity, type of bed used, intensity of kinetic therapy, and population under investigation. Outcomes assessed included the incidence of nosocomial pneumonia, mortality, duration of ventilation, and intensive care unit and hospital length of stay.

RESULTS

Fifteen prospective clinical trials were identified, which included a total of 1,169 participants. No trial met all the validity criteria. There was a significant reduction in the incidence of nosocomial pneumonia (pooled odds ratio (OR) 0.38, 95% confidence interval (CI) 0.28 to 0.53), but no reduction in mortality (pooled OR 0.96, 95%CI 0.66 to 1.14), duration of mechanical ventilation (pooled standardized mean difference (SMD) -0.14 days, 95%CI, -0.29 to 0.02), duration of intensive care unit stay (pooled SMD -0.064 days, 95% CI, -0.21 to 0.086) or duration of hospital stay (pooled SMD 0.05 days, 95% CI -0.18 to 0.27).

CONCLUSION

While kinetic bed therapy has been purported to reduce the incidence of nosocomial pneumonia in mechanically ventilated patients, the overall body of evidence is insufficient to support this conclusion. There appears to be a reduction in the incidence of nosocomial pneumonia, but no effect on mortality, duration of mechanical ventilation, or intensive care or hospital length of stay. Given the lack of consistent benefit and the poor methodological quality of the trials included in this analysis, definitive recommendations regarding the use of this therapy cannot be made at this time.

Early physiotherapy in the respiratory intensive care unit

Physiotherapy is an integral part of the management of patients in respiratory intensive care units (RICUs). The most important aim in this area is to enhance the overall patient's functional capacity and to restore his/her respiratory and physical independence, thus decreasing the risks of bed rest associated complications. This article is a review of evidence-based effectiveness of weaning practices and physiotherapy treatment for patients with respiratory insufficiency in a RICU. Literature searches were performed using general and specialty databases with appropriate keywords. The evidence for applying a weaning process and physiotherapy techniques in these patients has been described according to their individual rationale and efficacy. The growing number of patients treated in RICUs all over the world makes this non pharmacological approach both welcome and interesting. However, to date, there are only strong recommendations concerning the evidence-based strategies to speed weaning. Early physiotherapy may be effective in ICU: however, most techniques (postures, limb exercise and percussion/vibration in particular) need to be further studied in a large population. Evidence supporting physiotherapy intervention is limited as there are no studies examining the specific effects of interventions on long-term outcome.

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.

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.

Support surfaces for pressure ulcer prevention

BACKGROUND

Pressure ulcers (also known as bedsores, pressure sores, decubitus ulcers) are areas of localised damage to the skin and underlying tissue due to pressure, shear or friction. They are common in the elderly and immobile and costly in financial and human terms. Pressure-relieving beds, mattresses and seat cushions are widely used as aids to prevention in both institutional and non-institutional settings.

OBJECTIVES

This systematic review seeks to answer the following questions: to what extent do pressure-relieving cushions, beds, mattress overlays and mattress replacements reduce the incidence of pressure ulcers compared with standard support surfaces? how effective are different pressure-relieving surfaces in preventing pressure ulcers, compared to one another?

SEARCH STRATEGY

The Specialised Trials Register of the Cochrane Wounds Group (compiled from regular searches of many electronic databases including MEDLINE, CINAHL and EMBASE plus handsearching of specialist journals and conference proceedings) was searched up to January 2004, Issue 3, 2004 of the Cochrane Central Register of Controlled Trials was also searched. The reference sections of included studies were searched for further trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs), published or unpublished, which assessed the effectiveness of beds, mattresses, mattress overlays, and seating cushions for the prevention of pressure ulcers, in any patient group, in any setting. RCTs were eligible for inclusion if they reported an objective, clinical outcome measure such as incidence and severity of new of pressure ulcers developed. Studies which only reported proxy outcome measures such as interface pressure were excluded.

DATA COLLECTION AND ANALYSIS

Trial data were extracted by one researcher and checked by a second. The results from each study are presented as relative risk for dichotomous variables. Where deemed appropriate, similar studies were pooled in a meta analysis.

MAIN RESULTS

41 RCTs were included in the review. Foam alternatives to the standard hospital foam mattress can reduce the incidence of pressure ulcers in people at risk. The relative merits of alternating and constant low pressure devices, and of the different alternating pressure devices for pressure ulcer prevention are unclear.Pressure-relieving overlays on the operating table have been shown to reduce postoperative pressure ulcer incidence, although one study indicated that an overlay resulted in adverse skin changes. One trial indicated that Australian standard medical sheepskins prevented pressure ulcers. There is insufficient evidence to draw conclusions on the value of seat cushions, limb protectors and various constant low pressure devices as pressure ulcer prevention strategies.A study of Accident & Emergency trolley overlays did not identify a reduction in pressure ulcer incidence. There are tentative indications that foot waffle heel elevators, a particular low air loss hydrotherapy mattress and an operating theatre overlay are harmful.

REVIEWERS' CONCLUSIONS

In people at high risk of pressure ulcer development, consideration should be given to the use of higher specification foam mattresses rather than standard hospital foam mattresses. The relative merits of higher-tech constant low pressure and alternating pressure for prevention are unclear. Organisations might consider the use of pressure relief for high risk patients in the operating theatre, as this is associated with a reduction in post-operative incidence of pressure ulcers. Seat cushions and overlays designed for use in Accident & Emergency settings have not been adequately evaluated.

Body positioning of intensive care patients: clinical practice versus standards

OBJECTIVE

The routine turning of immobilized critically ill patients at a minimum of every 2 hrs has become the accepted standard of care. There has never been an objective assessment of whether this standard is achieved routinely. To determine if immobilized patients in the intensive care unit (ICU) receive the prevailing standard of change in body position every 2 hrs. To determine prevailing attitudes about patient positioning among ICU physicians.

DESIGN

Prospective longitudinal observational study. E-mail survey of ICU physicians.

SETTING AND PARTICIPANTS

Convenience sample of mixed medical/surgical ICU patients at three tertiary care hospitals in two different cities in the United States. Random sampling of ICU professionals from a directory.

MAIN OUTCOME MEASURES

Changes in body position recorded at 15-min intervals. RESULTS Seventy-four patients were observed for a total of 566 total patient hours of observation, with a mean observation time per patient of 7.7 hrs (range, 5-12). On average, 49.3% of the observed time, patients remained without a change in body position for >2 hrs. Only two of 74 patients (2.7%) had a demonstrable change in body position every 2 hrs. A total of 80-90% of respondents to the survey agreed that turning every 2 hrs was the accepted standard and that it prevented complications, but only 57% believed it was being achieved in their ICUs.

CONCLUSIONS

The majority of critically ill patients may not be receiving the prevailing standard of changes in body position every 2 hrs. This warrants a reappraisal of our care of critically ill patients.

Effect of continuous lateral rotational therapy on the prevalence of ventilator-associated pneumonia in patients requiring long-term ventilatory care

OBJECTIVE

To evaluate the role of continuous lateral rotational therapy on the development of ventilator-associated pneumonia in patients requiring long-term mechanical ventilation.

DESIGN

Prospective control study.

SETTING

Chronic ventilator unit in tertiary care hospital.

METHODS

Thirty-seven patients requiring long-term mechanical ventilation were assigned to receive either continuous lateral rotational therapy or conventional therapy.

RESULTS

Patients receiving continuous lateral rotational therapy had a significantly lower prevalence of pneumonia (17.6%) as compared with control patients (50%, p<.05). The development of pneumonia after being entered into the study was also significantly delayed in continuous lateral rotational therapy patients, 29 +/- 8 days vs. 12 +/- 2 days in controls (p <.05). However, unit mortality, total ventilator days, and the number of patients successfully weaned were not significantly different between groups.

CONCLUSION

In patients requiring long-term ventilator care, continuous lateral rotational therapy reduced the prevalence of pneumonia but did not seem to affect mortality or the period of mechanical ventilation.

Ventilator-associated pneumonia. Prevention, diagnosis, and therapy

Ventilator-associated pneumonia remains the nosocomial ICU infection of greatest concern. The authors have summarized the clinical trials that have assessed specific strategies to prevent VAP and the current controversies regarding the diagnosis and therapeutic approach to this condition. Improvements in care of patients who are at risk for or who have developed VAP will depend on the judicious application of this information for individual patients.

Clinical review: non-antibiotic strategies for preventing ventilator-associated pneumonia

Prevention of nosocomial pneumonia (NP) is the most important step towards reducing hospitalisation costs. The non-antibiotic prevention strategies include measures related to the correct care of the artificial airway, strategies related directly to the maintenance of the mechanical ventilator and the equipment, strategies focused in the gastrointestinal tract, and strategies related to the position of the intubated patients. While simple methods should be part of routine practice, the use of more invasive and expensive preventive measures should be used only in patients who are at high risk of NP. The appropriate use of these techniques can reduce the incidence of NP in intensive care unit patients.

Postoperative nosocomial pneumonia: nurse-sensitive interventions

Nosocomial pneumonia (NP) is well documented as the second most common nosocomial infection. It is now more common in surgical patients than surgical-site or wound infection. Healthcare implications of NP include not only increased patient morbidity and mortality, but also increased use of healthcare resources. The advanced practice nurse plays an integral role in the prevention and minimization of NP across healthcare settings. This article focuses on postoperative NP after abdominal, cardiac, or thoracic surgery in the non-mechanically ventilated patient and discusses the diagnostic assessment, risk factors, and potential nurse-sensitive interventions to prevent or minimize this complication. Ideas for potential nursing research related to these risk factors are described.

Ventilator circuit and secretion management strategies: a Franco-Canadian survey

OBJECTIVE

To determine the use of ventilator circuit and secretion management strategies in France and Canada.

DESIGN

Binational cross-sectional survey.

POPULATION

Intensive care unit (ICU) directors in French and Canadian university hospitals.

MEASUREMENTS

We compared responses between countries regarding the use of seven circuit and secretion strategies, the rationales against their use, decisional responsibility for these strategies, whether ventilator-associated pneumonia (VAP) practice was audited, and whether VAP prevention guidelines addressing these strategies were used.

RESULTS

The response rate was 72/84 (85.7%) for French and 31/32 (96.9%) for Canadian ICUs. Endotracheal intubation was predominantly oral in both countries. Changing the ventilator circuits only for every new patient was more frequent in France than in Canada (p < .0001). Heated humidifiers were used more in Canada than France (p = .0003). Closed endotracheal suctioning was used more frequently in Canada (p < .0001). In both countries, subglottic secretion drainage and kinetic beds were rarely used. Semirecumbent positioning was reported more often by French than Canadian ICUs (p = .003). Reasons for nonuse of these strategies included adverse effects (heat and moisture exchangers), cost (kinetic beds), lack of convincing benefit (subglottic secretion drainage), and nurse inconvenience (semirecumbency). Decisional responsibility for each strategy differed among institutions. VAP prevention practice was periodically reviewed in 53% of French and 68% of Canadian ICUs (p = .20). VAP prevention guidelines were used in 64% and 30% of these ICUs, respectively (p = .002).

CONCLUSIONS

Our study does not support the notion that published recommendations substantially impact reported use of several ventilator circuit and secretion management strategies. Based on the use of more frequent ventilator circuit changes, closed suctioning systems, heated humidifiers, and respiratory therapists, ventilator circuit and secretion management practice appears more costly in Canada than in France.

Epidemiology and risk factors for nosocomial pneumonia. Emphasis on prevention

VAP is a complex nosocomial infection, the disease expression and resulting patient outcome of which is dependent on host factors, the causative organism, the timing and adequacy of treatment, and the presence of intrinsic or inducible antibiotic resistance. Significant improvements have been achieved in our ability to reduce the occurrence of VAP in the hospital setting. Clinicians caring for mechanically ventilated patients should strive to develop focused programs for the prevention of VAP, other nosocomial infections, and the occurrence of antibiotic-resistant infections at their institutions. The benefits of such programs are well demonstrated. The components of a PDSA (Plan-Do-STUDY-Act) model that can be simply employed to develop a VAP prevention program are as follows: Stages Plan: 1. Identify potentially modifiable risk factors for VAP at the institutional level. 2. Develop a strategy to modify or prevent the occurrence of these risk factors. [figure: see text] Do: 1. Carry out the planned intervention strategy. 2. Identify problems in the implementation of the designed intervention. 3. Update the intervention with solutions for the identified problems. 4. Collect basic data (e.g., VAP rates, severity of illness).

STUDY

1. Analyze data. 2. Summarize the results. Act: 1. Determine the overall success or failure of the intervention. 2. Identify potential modifications to improve the intervention strategy. 3. Prepare for next PDSA cycle. Inherent in the development and application of such programs is the concept that they are continuous processes striving to improve clinical performance over time (Fig. 3). At any given institution, the most likely approach to the prevention of NP and VAP will be a multifaceted one, employing interventions aimed at reducing the occurrence of aerodigestive tract colonization with pathogenic bacteria and aspiration. To be successful, such quality improvement programs must be embraced at the institutional level. Only in this way can hospitals hope to successfully reduce their rates of VAP and sustain or improve upon those efforts over time.

Pulmonary host defenses. Implications for therapy

Pulmonary host defenses comprise a redundant system of protective mechanisms against invasion of the lungs by pathogenic microbes. The upper and lower airways are uniquely suited to contain and remove organisms that gain access to the respiratory mucosa. If the balance between host and organism is disputed, however, microbial clearance may be ineffective, and infection established. Pulmonary host defense mechanisms, which provide the basis for several current therapeutic strategies, are reviewed.

Therapy for ventilator-associated pneumonia

Pneumonia is a serious complication of mechanical ventilation. Pneumonia occurs despite the best efforts at prevention. Multiple methods available to prevent ventilator-associated pneumonia are reviewed, and ventilation-associated pneumonia (VAP) is divided into early versus late onset. The authors discuss the organisms associated with each of these situations, the empiric antibiotic choices, and specific issues related to antibiotic therapy such as resistance, pharmcodynamics, tissue penetration, and types of modifications necessary in empiric choice when the cause of VAP is identified.

Trendelenburg positioning and continuous lateral rotation improve oxygenation in hepatopulmonary syndrome after liver transplantation

Hepatopulmonary syndrome (HPS) is characterized by hypoxia, orthodeoxia, and platypnea, associated with severe chronic liver disease. Liver transplantation is generally viewed as the only curative treatment for this syndrome, but it may be complicated by prolonged hypoxia after the procedure. We report on a 58-year-old female patient with alcoholic cirrhosis and HPS who underwent liver transplantation. She developed severe hypoxia after transplantation that improved with the initiation of Trendelenburg's positioning in combination with continuous lateral rotation. Although many techniques for dealing with posttransplant hypoxia for HPS have been described, positioning is a simple maneuver that may correct the pathophysiologic abnormalities seen in HPS by gravitationally shifting blood away from the lung bases to improve oxygenation. Although this represents a single patient, the results were reproducible, and the intervention is simple and associated with minimal potential complications. The authors think this is a useful intervention to apply to the severely hypoxic patient with HPS, and a trial with more patients is warranted.

Acute effects of continuous rotational therapy on ventilation-perfusion inequality in lung injury

OBJECTIVE

To investigate ventilation-perfusion (VA/Q) relationships, during continuous axial rotation and in the supine position, in patients with acute lung injury (ALI) using the multiple inert gas elimination technique.

DESIGN

Prospective investigation.

SETTING

Eighteen-bed intensive care unit in a university hospital.

PATIENTS AND INTERVENTIONS

Ten patients with ALI (PaO2/FIO2 ratio < 300 mm Hg) were mechanically ventilated in a pressure controlled mode and placed on a kinetic treatment table.

MEASUREMENTS AND RESULTS

Distributions of VA/Q were determined 1) during rotation (after a period of 20 min) and 2) after a resting period of 20 min in the supine position. During axial rotation, intrapulmonary shunt (19.1 +/- 15% of cardiac output) was significantly reduced in comparison with when in the supine position (23 +/- 14%, p < 0.05), areas with "low" VA/Q were not affected by the positioning maneuver. General VA/Q mismatch (logarithmic distribution of pulmonary blood flow) was decreased during rotation (0.87 +/- 0.37) in comparison with when the patient was in the supine position (0.93 +/- 0.37, p < 0.05). Arterial oxygenation was significantly improved during continuous rotation (PaO2/FIO2 = 217 +/- 137 mm Hg) as compared with in the supine position (PaO2/FIO2 = 174 +/- 82 mm Hg, p < 0.05). The positive response of the continuous rotation on arterial oxygenation was only demonstrated in patients with a Murray Score of 2.5 or less, indicating a "mild to moderate" lung injury, while in patients presenting with progressive ARDS (Murray Score > 2.5), the acute positive response was limited.

CONCLUSIONS

Continuous axial rotation might be a method for an acute reduction of VA/Q mismatch in patients with mild to moderate ALI, but this technique is not effective in late or progressive ARDS. Further studies including a large data collection are needed.

Effects of extreme lateral posture on hemodynamics and plasma atrial natriuretic peptide levels in critically ill patients

OBJECTIVE

To quantify the hemodynamic effects of turning critically ill, mechanically ventilated patients to the extreme left and right lateral postures.

DESIGN

Prospective investigation.

SETTING

Eight-bed intensive care unit in a university hospital.

PATIENTS

Twelve consecutive patients presenting with severe respiratory failure and requiring continuous positive inotropic support.

INTERVENTIONS

All patients were mechanically ventilated and placed in a kinetic treatment system. They were positioned in the supine, left dependent, and right dependent postures, resting for 15 min in each position.

MEASUREMENTS AND RESULTS

Hemodynamic measurements, assessments of right ventricular function, and determinations of intrathoracic blood volume were performed in three different positions. Concentrations of atrial natriuretic peptide in plasma were quantified. In three patients, the findings were controlled by transesophageal echocardiography. Cardiac index [median (range) 5.5 (3.2-8.1) vs 4.3 (3.2-7.5) l/min per m2, p < 0.01], intrathoracic blood volume [1125 (820-1394) vs 1037 (821-1267) ml/m2, p < 0.01], and right ventricular end-diastolic volume [130 (83-159) vs 114 (79-155) ml/m2, p < 0.05] increased significantly in the left dependent position compared to supine. Mean arterial pressure did not change. Atrial natriuretic peptide levels rose from 140 to 203 pg/ml. In the right dependent position, we found a marked decrease in the mean arterial pressure [85 mmHg (supine) to 72 mmHg (right dependent), p < 0.01]. Cardiac index and intrathoracic blood volume were unchanged, but right ventricular end-diastolic volume decreased from 114 to 102 ml/m2 (p < 0.05). Additionally, atrial natriuretic peptide levels decreased significantly (median delta value: 37 pg/ml). In echocardiographic controls we found an increase in right ventricular end-diastolic diameters in the left dependent position and shortened diameters in the right dependent position.

CONCLUSIONS

Extreme lateral posture affects the cardiovascular system in critically ill, mechanically ventilated patients: in the left dependent position a "hyperdynamic state" is reinforced, while the right decubitus position impairs right ventricular preload and predisposes to hypotension. Echocardiography and changes in plasma atrial natriuretic peptide values indicate that these findings are due to altered distensibility of the right ventricle caused by regional intrathoracic gravitational changes. We conclude that the duration and the angle of lateral posture should be restricted in hemodynamically unstable patients.