Recruitment manoeuvres for adults with acute respiratory distress syndrome receiving mechanical ventilation.

BACKGROUND: Recruitment manoeuvres involve transient elevations in airway pressure applied during mechanical ventilation to open ('recruit') collapsed lung units and increase the number of alveoli participating in tidal ventilation. Recruitment manoeuvres are often used to treat patients in intensive care who have acute respiratory distress syndrome (ARDS), but the effect of this treatment on clinical outcomes has not been well established. This systematic review is an update of a Cochrane review originally published in 2009. OBJECTIVES: Our primary objective was to determine the effects of recruitment manoeuvres on mortality in adults with acute respiratory distress syndrome.Our secondary objective was to determine, in the same population, the effects of recruitment manoeuvres on oxygenation and adverse events (e.g. rate of barotrauma). SEARCH METHODS: For this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), Embase (OVID), the Cumulative Index to Nursing and Allied Health Literature (CINAHL, EBSCO), Latin American and Caribbean Health Sciences (LILACS) and the International Standard Randomized Controlled Trial Number (ISRCTN) registry from inception to August 2016. SELECTION CRITERIA: We included randomized controlled trials (RCTs) of adults who were mechanically ventilated that compared recruitment manoeuvres versus standard care for patients given a diagnosis of ARDS. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information. MAIN RESULTS: Ten trials met the inclusion criteria for this review (n = 1658 participants). We found five trials to be at low risk of bias and five to be at moderate risk of bias. Six of the trials included recruitment manoeuvres as part of an open lung ventilation strategy that was different from control ventilation in aspects other than the recruitment manoeuvre (such as mode of ventilation, higher positive end-expiratory pressure (PEEP) titration and lower tidal volume or plateau pressure). Six studies reported mortality outcomes. Pooled data from five trials (1370 participants) showed a reduction in intensive care unit (ICU) mortality (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.72 to 0.97, P = 0.02, low-quality evidence), pooled data from five trials (1450 participants) showed no difference in 28-day mortality (RR 0.86, 95% CI 0.74 to 1.01, P = 0.06, low-quality evidence) and pooled data from four trials (1313 participants) showed no difference in in-hospital mortality (RR 0.88, 95% CI 0.77 to 1.01, P = 0.07, low-quality evidence). Data revealed no differences in risk of barotrauma (RR 1.09, 95% CI 0.78 to 1.53, P = 0.60, seven studies, 1508 participants, moderate-quality evidence). AUTHORS' CONCLUSIONS: We identified significant clinical heterogeneity in the 10 included trials. Results are based upon the findings of several (five) trials that included an "open lung ventilation strategy", whereby the intervention group differed from the control group in aspects other than the recruitment manoeuvre (including co-interventions such as higher PEEP, different modes of ventilation and higher plateau pressure), making interpretation of the results difficult. A ventilation strategy that included recruitment manoeuvres in participants with ARDS reduced intensive care unit mortality without increasing the risk of barotrauma but had no effect on 28-day and hospital mortality. We downgraded the quality of the evidence to low, as most of the included trials provided co-interventions as part of an open lung ventilation strategy, and this might have influenced results of the outcome.

Barriers and facilitators to early mobilisation in Intensive Care: a qualitative study.

OBJECTIVES: To determine the barriers and facilitators of early mobilisation in the Intensive Care Unit. BACKGROUND: It is well established that mobilising critically ill patients has many benefits, however it is not occurring as frequently as expected. The causes and ways to change this are not clearly understood. METHODS: A qualitative descriptive study involving focus groups with medical, nursing and physiotherapy clinicians, from an Australian quaternary hospital Intensive Care Unit. RESULTS: The major themes related to barriers included the culture of the Intensive Care Unit; communication; and a lack of resources. Major themes associated with facilitating early mobilisation included organisational change; improved communication between medical units; and improved resources. CONCLUSIONS: Early mobilisation was considered an important aspect of critically ill patient's care by all clinicians. Several major barriers to mobilisation were identified, which included unit culture, lack of resources, prioritisation and leadership. A dedicated mobility team led by physiotherapists in the ICU setting could be a viable option to address the identified barriers related to mobility.

Effects of exercise training on exercise capacity and quality of life in patients with a left ventricular assist device: a preliminary randomized controlled trial.

BACKGROUND: A paucity of studies has examined the effect of exercise training after left ventricular assist device (LVAD) implantation. Previous research has demonstrated that insertion of the LVAD alone improves exercise capacity and quality of life (QOL). This study investigated whether supervised exercise training results in a further improvement. METHODS: This prospective, randomized controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis investigated the effect of exercise training on exercise capacity and QOL in 14 patients who underwent LVAD insertion as a bridge to heart transplantation. Exercise training consisted of 8 weeks of gym-based aerobic and strengthening exercises 3 times a week, with a progressive mobilization program, compared with the control group that completed mobilization alone. Exercise capacity was measured before and after the intervention using maximal cardiopulmonary exercise testing and 6-minute walk distance (6MWD). QOL was measured using the Short Form 36-item assessment. RESULTS: No adverse events were reported. There was a trend toward greater improvement in peak oxygen consumption (Vo(2)), 6MWD, and QOL in the exercise group (n = 7) compared with the control group (n = 7); however, no significant between-group difference was detected for improvements in peak Vo(2) [mean difference (exercise--control)] of 2.96 ml/kg/min (95% confidence interval, -1.04 to 6.97), 6MWD at 54 meters (-51 to 159 meters), and QOL scores over time (p > 0.05). CONCLUSION: Exercise training is feasible and safe in patients with a LVAD. Trends toward greater improvement in exercise capacity and QOL after exercise training warrant further investigation in a larger trial.

Recruitment manoeuvres for adults with acute lung injury receiving mechanical ventilation.

BACKGROUND: Recruitment manoeuvres are often used to treat patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) but the effect of this treatment on clinical outcomes has not been well established. OBJECTIVES: The objective of this review was to examine recruitment manoeuvres compared to standard care as therapy for adults with acute lung injury in order to quantify the effects on patient outcomes (mortality, length of ventilation, and other relevant outcomes). SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 2); MEDLINE (January 1966 to May 2008); EMBASE (January 1980 to May 2008); LILACS (1982 to May 2008); CINAHL (1982 to May 2008); and Current Controlled Trials (www.controlled-trials.com). SELECTION CRITERIA: We included randomized controlled trials of adults who were mechanically ventilated comparing recruitment manoeuvres to standard care for those patients diagnosed with ALI or ARDS. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. MAIN RESULTS: Seven trials met the inclusion criteria for this review (the total number of included participants was 1170). All trials included a recruitment manoeuvre as part of the treatment strategy for patients on mechanical ventilation for ARDS or ALI. However, two of the trials included a package of ventilation that was different from the control ventilation in aspects other than the recruitment manoeuvre. The intervention group showed no significant difference on 28-day mortality (RR 0.73, 95% CI 0.46 to 1.17, P = 0.2). Similarly there was no statistical difference for risk of barotrauma (RR 0.50, 95% CI 0.07 to 3.52, P = 0.5) or blood pressure (MD 0.9 mm Hg, 95% CI -4.28 to 6.08, P = 0.73). Recruitment manoeuvres significantly increased oxygenation above baseline levels for a short period of time in four of the five studies that measured oxygenation. There were insufficient data on length of ventilation or hospital stay to pool results. AUTHORS' CONCLUSIONS: There is not evidence to make conclusions on whether recruitment manoeuvres reduce mortality or length of ventilation in patients with ALI or ARDS.

Skeletal muscle neuronal nitric oxide synthase micro protein is reduced in people with impaired glucose homeostasis and is not normalized by exercise training.

Skeletal muscle inducible nitric oxide synthase (NOS) protein is greatly elevated in people with type 2 diabetes mellitus, whereas endothelial NOS is at normal levels. Diabetic rat studies suggest that skeletal muscle neuronal NOS (nNOS) micro protein expression may be reduced in human insulin resistance. The aim of this study was to determine whether skeletal muscle nNOSmicro protein expression is reduced in people with impaired glucose homeostasis and whether exercise training increases nNOSmicro protein expression in these individuals because exercise training increases skeletal muscle nNOSmicro protein in rats. Seven people with type 2 diabetes mellitus or prediabetes (impaired fasting glucose and/or impaired glucose tolerance) and 7 matched (sex, age, fitness, body mass index, blood pressure, lipid profile) healthy controls aged 36 to 60 years participated in this study. Vastus lateralis muscle biopsies for nNOSmicro protein determination were obtained, aerobic fitness was measured (peak pulmonary oxygen uptake [Vo(2) peak]), and glucose tolerance and insulin homeostasis were assessed before and after 1 and 4 weeks of cycling exercise training (60% Vo(2) peak, 50 minutes x 5 d wk(-1)). Skeletal muscle nNOSmicro protein was significantly lower (by 32%) in subjects with type 2 diabetes mellitus or prediabetes compared with that in controls before training (17.7 +/- 1.2 vs 26.2 +/- 3.4 arbitrary units, P < .05). The Vo(2) peak and indicators of insulin sensitivity improved with exercise training in both groups (P < .05), but there was no effect of exercise training on skeletal muscle nNOSmicro protein in either group. In conclusion, individuals with impaired glucose homeostasis have reduced skeletal muscle nNOSmicro protein content. However, because exercise training improves insulin sensitivity without influencing skeletal muscle nNOSmicro protein expression, it seems that changes in skeletal muscle nNOSmicro protein are not central to the control of insulin sensitivity in humans and therefore may be a consequence rather than a cause of diabetes.

Skeletal muscle nNOS mu protein content is increased by exercise training in humans.

The major isoform of nitric oxide synthase (NOS) in skeletal muscle is the splice variant of neuronal NOS, termed nNOS mu. Exercise training increases nNOS mu protein levels in rat skeletal muscle, but data in humans are conflicting. We performed two studies to determine 1) whether resting nNOS mu protein expression is greater in skeletal muscle of 10 endurance-trained athletes compared with 11 sedentary individuals (study 1) and 2) whether intense short-term (10 days) exercise training increases resting nNOS mu protein (within whole muscle and also within types I, IIa, and IIx fibers) in eight sedentary individuals (study 2). In study 1, nNOS mu protein was approximately 60% higher (P < 0.05) in endurance-trained athletes compared with the sedentary participants. In study 2, nNOS mu protein expression was similar in types I, IIa, and IIx fibers before training. Ten days of intense exercise training significantly (P < 0.05) increased nNOS mu protein levels in types I, IIa, and IIx fibers, a finding that was validated by using whole muscle samples. Endothelial NOS and inducible NOS protein were barely detectable in the skeletal muscle samples. In conclusion, nNOS mu protein expression is greater in endurance-trained individuals when compared with sedentary individuals. Ten days of intense exercise is also sufficient to increase nNOS mu expression in untrained individuals, due to uniform increases of nNOS mu within types I, IIa, and IIx fibers.

Type 2 diabetic individuals have impaired leg blood flow responses to exercise: role of endothelium-dependent vasodilation.

OBJECTIVE: Diabetic individuals have impaired endothelium-dependent forearm vasodilatory responses to ischemia, acetylcholine, and other endothelium-dependent agonists. The functional significance of impaired endothelium-dependent dilation in diabetic individuals is uncertain but is most likely to be manifest during leg muscle exercise and may have relevance to peripheral vascular disease and leg ischemia, which is prevalent in diabetic individuals. The current study aimed to determine the relationship between leg blood flow (LBF) responses to endothelium-dependent vasodilation and dynamic large muscle exercise. RESEARCH DESIGN AND METHODS: LBF responses (thermodilution) to intrafemoral arterial infusions of an endothelium-dependent (acetylcholine) and endothelium-independent (sodium nitroprusside) vasodilator and a standardized 25-min cycling bout at 60% VO(2peak) were compared in nine male type 2 diabetic subjects and nine age-, sex-, VO(2peak)-, and weight-matched control subjects. RESULTS: LBF responses to acetylcholine and exercise but not sodium nitroprusside were significantly (P < 0.05) attenuated in patients with diabetes compared with healthy control subjects. The percentage increase in LBF in response to exercise and acetylcholine were significantly correlated (r = 0.54, P = 0.02). Furthermore, resting plasma glucose was significantly related to the LBF response to exercise (r = -0.66, P = 0.003) independently of insulin, HbA(1c), lipids, BMI, and blood pressure. CONCLUSIONS: The increase in LBF during exercise is substantially attenuated in type 2 diabetic compared with matched control subjects. Impaired endothelium-dependent vasodilation secondary to elevated plasma glucose may underlie this observation. This mechanism may be of importance in determining the leg ischemic threshold in diabetic individuals with peripheral vascular disease.

Nitric oxide synthase inhibition reduces glucose uptake during exercise in individuals with type 2 diabetes more than in control subjects.

Nitric oxide (NO) synthase inhibition reduces leg glucose uptake during cycling without reducing leg blood flow (LBF) in young, healthy individuals. This study sought to determine the role of NO in glucose uptake during exercise in individuals with type 2 diabetes. Nine men with type 2 diabetes and nine control subjects matched for age, sex, peak pulmonary oxygen uptake (VO(2) peak), and weight completed two 25-min bouts of cycling exercise at 60 +/- 2% VO(2) peak, separated by 90 min. N(G)-monomethyl-L-arginine (L-NMMA) (total dose 6 mg/kg) or placebo was administered into the femoral artery for the final 15 min of exercise in a counterbalanced, blinded, crossover design. LBF was measured by thermodilution in the femoral vein, and leg glucose uptake was calculated as the product of LBF and femoral arteriovenous glucose difference. During exercise with placebo, glucose uptake was not different between control subjects and individuals with diabetes; however, LBF was lower and arterial plasma glucose and insulin levels were higher in individuals with diabetes. L-NMMA had no effect on LBF or arterial plasma glucose and insulin concentrations during exercise in both groups. L-NMMA significantly reduced leg glucose uptake in both groups, with a significantly greater reduction (P = 0.04) in the diabetic group (75 +/- 13%, 5 min after L-NMMA) compared with the control group (34 +/- 14%, 5 min after L-NMMA). These data suggest a greater reliance on NO for glucose uptake during exercise in individuals with type 2 diabetes compared with control subjects.