Outcomes of patients admitted to intensive care units for acute manifestation of small-vessel vasculitis: a multicenter, retrospective study

Outcomes of patients admitted to intensive care units for acute manifestation of small-vessel vasculitis: a multicenter, retrospective study
Critical Care 2016 20:27 DOI: 10.1186/s13054-016-1189-5
Kimmoun A et al


Background: The outcomes of patients admitted to the intensive care unit (ICU) for acute manifestation of small-vessel vasculitis are poorly reported. The aim of the present study was to determine the mortality rate and prognostic factors of patients admitted to the ICU for acute small-vessel vasculitis. Methods: This retrospective, multicenter study was conducted from January 2001 to December 2014 in 20 ICUs in France. Patients were identified from computerized registers of each hospital using the International Classification of Diseases, Ninth Revision (ICD-9). Inclusion criteria were (1) known or highly suspected granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis (respectively, ICD-9 codes M31.3, M30.1, and M31.7), or anti–glomerular basement membrane antibody disease (ICD-9 codes N08.5X-005 or M31.0+); (2) admission to the ICU for the management of an acute manifestation of vasculitis; and (3) administration of a cyclophosphamide pulse in the ICU or within 48 h before admission to the ICU. The primary endpoint was assessment of mortality rate 90 days after admission to the ICU. Results: Eighty-two patients at 20 centers were included, 94 % of whom had a recent ...................see full article

Economic Evaluation of Telemedicine for Patients in ICUs

Economic Evaluation of Telemedicine for Patients in ICUs
Critical Care Medicine: February 2016 - Volume 44 - Issue 2 - p 265–274
Byung-Kwang Y et al


Objective: Despite telemedicine’s potential to improve patients’ health outcomes and reduce costs in the ICU, hospitals have been slow to introduce telemedicine in the ICU due to high up-front costs and mixed evidence on effectiveness. This study’s first aim was to conduct a cost-effectiveness analysis to estimate the incremental cost-effectiveness ratio of telemedicine in the ICU, compared with ICU without telemedicine, from the healthcare system perspective. The second aim was to examine potential cost saving of telemedicine in the ICU through probabilistic analyses and break-even analyses. Design: Simulation analyses performed by standard decision models. Setting: Hypothetical ICU defined by the U.S. literature. Patients: Hypothetical adult patients in ICU defined by the U.S. literature. Interventions: The intervention was the introduction of telemedicine in the ICU, which was assumed to affect per-patient per-hospital-stay ICU cost and hospital mortality. Telemedicine in the ICU operation costs included the telemedicine equipment-installation (start-up) costs with 5-year depreciation, maintenance costs, and clinician staffing costs. Telemedicine in the ICU effectiveness was measured by cumulative quality-adjusted life years for 5 years after ICU discharge. Measurements and Main Results: The base case cost-effectiveness analysis estimated telemedicine in the ICU to extend 0.011 quality-adjusted life years with an incremental cost of $516 per patient compared with ICU without telemedicine, resulting in an incremental cost-effectiveness ratio of $45,320 per additional quality-adjusted life year (= $516/0.011). The probabilistic cost-effectiveness analysis estimated an incremental cost-effectiveness ratio of $50,265 with a wide 95% CI from a negative value (suggesting cost savings) to $375,870. These probabilistic analyses projected that cost saving is achieved 37% of 1,000 iterations. Cost saving is also feasible if the per-patient per-hospital-stay operational cost and physician cost were less than $422 and less than $155, respectively, based on break-even analyses. Conclusions: Our analyses suggest that telemedicine in the ICU is cost-effective in most cases and cost saving in some cases. The thresholds of cost and effectiveness, estimated by break-even analyses, help hospitals determine the impact of telemedicine in the ICU and potential cost saving.

Reported burden on informal caregivers of ICU survivors: a literature review

Reported burden on informal caregivers of ICU survivors: a literature review
Critical Care 2016 20:16 DOI: 10.1186/s13054-016-1185-9
van Beusekom I et al


Background: Critical illness and the problems faced after ICU discharge do not only affect the patient, it also negatively impacts patients’ informal caregivers. There is no review which summarizes all types of burden reported in informal caregivers of ICU survivors. It is important that the burdens these informal caregivers suffer are systematically assessed so the caregivers can receive the professional care they need. We aimed to provide a complete overview of the types of burdens reported in informal caregivers of adult ICU survivors, to make recommendations on which burdens should be assessed in this population, and which tools should be used to assess them.MethodWe performed a systematic search in PubMed and CINAHL from database inception until June 2014. All articles reporting on burdens in informal caregivers of adult ICU survivors were included. Two independent reviewers used a standardized form to extract characteristics of informal caregivers, types of burdens and instruments used to assess these burdens. The quality of the included studies was assessed using the Newcastle-Ottawa and the PEDro scales. Results: The search yielded 2704 articles, of which we included 28 in our review. The most commonly reported outcomes were psychosocial burden. Six months after ICU discharge, the prevalence of anxiety was between 15 % and 24 %, depression between 4.7 % and 36.4 % and post-traumatic stress disorder (PTSD) between 35 % and 57.1 %. Loss of employment, financial burden, lifestyle interference and low health-related quality of life (HRQoL) were also frequently reported. The most commonly used tools were the Hospital Anxiety and Depression Scale (HADS), Centre for Epidemiological Studies-Depression questionnaire, and Impact of Event Scale (IES). The quality of observational studies was low and of randomized studies moderate to fair. Conclusions: Informal caregivers of ICU survivors suffer a substantial variety of burdens. Although the quality of the included studies was poor, there is evidence that burden in the psychosocial field is most prevalent. We suggest screening informal caregivers of ICU survivors for anxiety, depression, PTSD, and HRQoL using respectively the HADS, IES and Short Form 36 and recommend a follow-up period of at least 6 months.

Recruitment Maneuvers and Positive End-Expiratory Pressure Titration in Morbidly Obese ICU Patients

Recruitment Maneuvers and Positive End-Expiratory Pressure Titration in Morbidly Obese ICU Patients
Critical Care Medicine: February 2016 - Volume 44 - Issue 2 - p 300–307
Pirrone, M et al

Objective: The approach to applying positive end-expiratory pressure in morbidly obese patients is not well defined. These patients frequently require prolonged mechanical ventilation, increasing the risk for failed liberation from ventilatory support. We hypothesized that lung recruitment maneuvers and titration of positive end-expiratory pressure were both necessary to improve lung volumes and the elastic properties of the lungs, leading to improved gas exchange. Design: Prospective, crossover, nonrandomized interventional study. Setting: Medical and surgical ICUs at Massachusetts General Hospital. Patients: Critically ill, mechanically ventilated morbidly obese (body mass index > 35 kg/m2) patients (n = 14). Interventions: This study evaluated two methods of titrating positive end-expiratory pressure; both trials were done utilizing positive end-expiratory pressure titration and recruitment maneuvers while measuring hemodynamics and respiratory mechanics. Measurements were obtained at the baseline positive end-expiratory pressure set by the clinicians, at zero positive end-expiratory pressure, at best positive end-expiratory pressure identified through esophageal pressure measurement before and after a recruitment maneuver, and at best positive end-expiratory pressure identified through a best decremental positive end-expiratory pressure trial. Measurements and Main Results: The average body mass index was 50.7 ± 16.0 kg/m2. The two methods of evaluating positive end-expiratory pressure identified similar optimal positive end-expiratory pressure levels (20.7 ± 4.0 vs 21.3 ± 3.8 cm H2O; p = 0.40). End-expiratory pressure titration increased end-expiratory lung volumes (Δ11 ± 7 mL/kg; p < 0.01) and oxygenation (Δ86 ± 50 torr; p < 0.01) and decreased lung elastance (Δ5 ± 5 cm H2O/L; p < 0.01). Recruitment maneuvers followed by titrated positive end-expiratory pressure were effective at increasing end-expiratory lung volumes while decreasing end-inspiratory transpulmonary pressure, suggesting an improved distribution of lung aeration and reduction of overdistension. The positive end-expiratory pressure levels set by the clinicians (11.6 ± 2.9 cm H2O) were associated with lower lung volumes, worse elastic properties of the lung, and lower oxygenation. Conclusions: Commonly used positive end-expiratory pressure by clinicians is inadequate for optimal mechanical ventilation of morbidly obese patients. A recruitment maneuver followed by end-expiratory pressure titration was found to significantly improve lung volumes, respiratory system elastance, and oxygenation.

Elevated high-sensitive troponin T on admission is an indicator of poor long-term outcome in patients with subarachnoid haemorrhage: a prospective observational study

Elevated high-sensitive troponin T on admission is an indicator of poor long-term outcome in patients with subarachnoid haemorrhage: a prospective observational study
Critical Care 2016 20:11 DOI: 10.1186/s13054-015-1181-5
Oras J, et al


Background: Patients with subarachnoid haemorrhage (SAH) frequently develop cardiac complications in the acute phase after the bleeding. Although a number of studies have shown that increased levels of cardiac biomarkers after SAH are associated with a worse short-term prognosis, no prospective, consecutive study has assessed the association between biomarker release and long-term outcome. We aimed to evaluate whether the cardiac biomarkers, high-sensitive troponin T (hsTnT) and N-terminal pro B-type natriuretic peptide (NTproBNP), were associated with poor 1-year neurological outcome and cerebral infarction due to delayed cerebral ischaemia (CI-DCI). ....See full article

Equity of Access to Critical Care Among Elderly Patients in Scotland: A National Cohort Study

Equity of Access to Critical Care Among Elderly Patients in Scotland: A National Cohort Study

Critical Care Medicine: January 2016 - Volume 44 - Issue 1 - p 3–13
Docherty, A; Anderson, N et al


Objective: To compare elderly (≥ 80 yr), older (65–79 yr), and younger (< 65 yr) ICU admissions in Scotland in relation to trends in admission rates, regional variation in admissions, ICU treatment intensity, and ICU and 1-year mortality. Design: National 5-year cohort study of ICU first admissions (January 1, 2005, to December 31, 2009). Setting: All admissions to ICUs and combined units (level 2/3 care) in Scotland captured by the Scottish Intensive Care Society Audit Group database, linked with hospital discharge data and death records. Patients: A total of 40,142 patients: 3,865 were 80 years old or older (9.6%), 13,904 (34.6%) were 65–79 years old; and 22,373 were younger than 65 years (55.7%). Interventions: None. Measurements and Main Results: Between 2005 and 2009, elderly admission rates decreased from 36.6/10,000 (95% CI, 34.0–39.2) in 2005 to 28.7/10,000 (95% CI, 26.5–30.9) in 2009 (p < 0.001; relative decrease, 22.0%); older admission rates also decreased, but less steeply (31.1 [95% CI, 29.9–32.2] to 26.1 [95% CI, 25.1–27.1] per 10,000 population; p < 0.001; relative decrease, 16.1%). Rates were static for younger patients. Restricted to mechanically ventilated elderly patients, rates ranged from 13.9 to 30.1/10,000 between healthboard administrative regions (p < 0.001). Emergency surgical diagnoses were more prevalent for elderly patients (elderly, 39.8%; older, 25.1%; younger, 20.3%; p < 0.001). Subgroup analyses limited to pneumonia admissions (elderly, n = 242; older, n = 1,226; younger, n = 1,836) indicated similar acute physiology scores, but fewer preexisting comorbidities among elderly patients (p = 0.007), who received a shorter duration of organ support and ICU stay. Mortality rates were higher in elderly patients at ICU discharge (elderly, 26.5%; older, 25.0%; younger, 17.0%; p < 0.001; confounder adjusted odds ratio elderly vs younger, 2.33 [95% CI, 2.11–2.58]; p < 0.001). Differences persisted at 1 year (elderly, 52.2%; older, 43.8%; younger, 27.6%; adjusted odds ratio elderly vs younger, 3.72 [95% CI, 3.42–4.06]; p < 0.001). Conclusions: In Scotland, elderly and older ICU admission rates are decreasing, with regional geographic variation. Although limited by an absence of a measure of frailty, patient characteristics and treatment intensity suggest selection of less comorbid elderly patients, indicating possible rationing based on chronologic age.

Delayed Rapid Response Team Activation Is Associated With Increased Hospital Mortality, Morbidity, and Length of Stay in a Tertiary Care Institution

Delayed Rapid Response Team Activation Is Associated With Increased Hospital Mortality, Morbidity, and Length of Stay in a Tertiary Care Institution

Critical Care Medicine: January 2016 - Volume 44 - Issue 1 - p 54–63
Barwise, A, Thongprayoon, C et al


Objective: To identify whether delays in rapid response team activation contributed to worse patient outcomes (mortality and morbidity). Design: Retrospective observational cohort study including all rapid response team activations in 2012. Setting: Tertiary academic medical center. Patients: All those 18 years old or older who had a rapid response team call activated. Vital sign data were abstracted from individual patient electronic medical records for the 24 hours before the rapid response team activation took place. Patients were considered to have a delayed rapid response team activation if more than 1 hour passed between the first appearance in the record of an abnormal vital sign meeting rapid response team criteria and the activation of an rapid response team. Interventions: None. Measurements and Main Results: A total of 1,725 patients were included in the analysis. Data were compared between those who had a delayed rapid response team activation and those who did not. Fifty seven percent patients met the definition of delayed rapid response team activation. Patients in high-frequency physiologic monitored environments were more likely to experience delay than their floor counterparts. In the no-delay group, the most common reasons for rapid response team activation were tachycardia/bradycardia at 29% (217/748), respiratory distress/low SpO2 at 28% (213/748), and altered level of consciousness at 23% (170/748) compared with respiratory distress/low SpO2 at 43% (423/977), tachycardia/bradycardia at 33% (327/977), and hypotension at 27% (261/977) in the delayed group. The group with no delay had a higher proportion of rapid response team calls between 8:00 and 16:00, whereas those with delay had a higher proportion of calls between midnight and 08:00. The delayed group had higher hospital mortality (15% vs 8%; adjusted odds ratio, 1.6; p = 0.005); 30-day mortality (20% vs 13%; adjusted odds ratio, 1.4; p = 0.02); and hospital length of stay (7 vs 6 d; relative prolongation, 1.10; p = 0.02) compared with the no-delay group. Conclusions: Delays in rapid response team activation occur frequently and are independently associated with worse patient mortality and morbidity outcomes.

Noise Levels in Surgical ICUs Are Consistently Above Recommended Standards

NoiseLevels in Surgical ICUs Are Consistently Above Recommended Standards
Critical Care Medicine: January 2016 - Volume 44 - Issue 1 - p 147–152
Tainter, CR, Levine, AR et al


Objective: The equipment, monitor alarms, and acuity of patients in ICUs make it one of the loudest patient care areas in a hospital. Increased sound levels may contribute to worsened outcomes in these particularly vulnerable patients. Our objective was to determine whether ambient sound levels in surgical ICUs comply with recommendations established by the World Health Organization and Environmental Protection Agency, and whether implementation of an overnight “quiet time” intervention is associated with lower ambient sound levels. Design: Prospective, observational cohort study. Setting: Two comparable 18-bed, surgical ICUs in a large, teaching hospital. Only one ICU had a formal overnight quiet time policy at the start of the study period. Measurements and Main Results: Sound levels were measured in 30-second blocks at preselected locations during the day and night over a period of 6 weeks using a simple, hand-held sound meter. All sound measurements in both units at all times exceeded recommended standards. Median minimum sound levels were lower at night in both units (50.8 and 50.3 vs 53.1 and 51.0 dB, p = 0.0003 and p = 0.009) and were similar between the two units (p = 0.52). The maximum overnight sound levels were statistically lower in the unit with the quiet time intervention implemented (62.5 vs 59.6 dB; p = 0.0040) and decreased overnight immediately after implementation of quiet time in the other unit (62.5 vs 56.1 dB; p < 0.0001). Maximum sound levels were lower inside patient rooms (52.2 vs 55.3 dB; p = 0.004), but minimum sound levels were similar (49.1 vs 49.2 dB; p = 0.23). Linear regression analysis showed that ICU census did not significantly influence sound levels. Conclusions: Ambient sound levels in the surgical ICUs were consistently above levels recommended by the World Health Organization and Environmental Protection Agency at all times. The use of a formal quiet time intervention was associated with a significant, but clinically irrelevant reduction in the median maximum sound level at night. Our results suggest that excessive ambient noise in the ICU is largely attributable to environmental factors, and behavior modifications are unlikely to have a meaningful impact. Future investigations, as well as hospital designs, should target interventions toward ubiquitous noise sources such as ventilation systems, which may not traditionally be associated with patient care.

Validity of a Modified Sequential Organ Failure Assessment Score Using the Richmond Agitation-Sedation Scale

Validityof a Modified Sequential Organ Failure Assessment Score Using the RichmondAgitation-Sedation Scale
Critical Care Medicine: January 2016 - Volume 44 - Issue 1 - p 138–146
Vasilevskis, EE, Pandharipande, PP, et al


Objectives: The Sequential Organ Failure Assessment and other severity of illness scales rely on the Glasgow Coma Scale to measure acute neurologic dysfunction, but the Glasgow Coma Scale is unavailable or inconsistently applied in some institutions. The objective of this study was to assess the validity of a modified Sequential Organ Failure Assessment that uses the Richmond Agitation-Sedation Scale instead of Glasgow Coma Scale. Design: Prospective cohort study. Setting: Medical and surgical ICUs within a large, tertiary care hospital. Patients: Critically ill medical/surgical ICU patients. Interventions: We calculated daily Sequential Organ Failure Assessment scores by using electronic medical record-derived data. By using bedside nurse-recorded Glasgow Coma Scale and Richmond Agitation-Sedation Scale measures, we calculated neurologic Sequential Organ Failure Assessment scores using the original Glasgow Coma Scale–based approach and a novel Richmond Agitation-Sedation Scale–based approach, converting the 10-point Richmond Agitation-Sedation Scale to a 4-point neurologic Sequential Organ Failure Assessment score. We assessed construct validity of Richmond Agitation-Sedation Scale–based Sequential Organ Failure Assessment by analyzing correlations with established severity of illness constructs (Acute Physiology and Chronic Health Evaluation II and Glasgow Coma Scale–based Sequential Organ Failure Assessment) and predictive validity by using logistic regression to determine whether Richmond Agitation-Sedation Scale–based Sequential Organ Failure Assessment predicts ICU, hospital, and 1-year mortality. We assessed discriminative performance with c-statistics. Measurements and Main Results: Among 513 patients (5,199 patient-days), Richmond Agitation-Sedation Scale–based Sequential Organ Failure Assessment was strongly correlated with Acute Physiology and Chronic Health Evaluation II acute physiology score at enrollment (r = 0.583; 95% CI, 0.518–0.642) and daily Glasgow Coma Scale–based Sequential Organ Failure Assessment scores (r = 0.963; 95% CI, 0.956–0.968). Mean Richmond Agitation-Sedation Scale–based Sequential Organ Failure Assessment scores predicted ICU mortality (areas under the curve = 0.814)—as did mean Glasgow Coma Scale–based Sequential Organ Failure Assessment (0.799)—as well as hospital and 1-year mortality. Admission Sequential Organ Failure Assessment scores, whether using Richmond Agitation-Sedation Scale or Glasgow Coma Scale, were less accurate predictors of mortality; areas under the curves for ICU mortality for Richmond Agitation-Sedation Scale–based and Glasgow Coma Scale–based Sequential Organ Failure Assessment, for example, were 0.622 and 0.608, respectively. Conclusion: A modified Sequential Organ Failure Assessment score that uses bedside Richmond Agitation-Sedation Scale when Glasgow Coma Scale data are not available is a valid means of assessing daily severity of illness in the ICU and may be valuable for risk-adjustment and benchmarking purposes.

Intensive care nurses’ experiences of end-of-life care

Intensive care nurses’ experiences of end-of-life care
Intensive and Critical Care Nursing Article in press
Kisorio,LC ,  Langley G C

Purpose: To explore intensive care nurses’ experiences of end-of-life care in adult intensive care units.

Design and methods: An exploratory, descriptive qualitative approach was utilised. Purposive sampling method was used to select nurse participants (n = 24) working at the selected intensive care units in the three academic affiliated, tertiary specialist hospitals in the Johannesburg and Pretoria regions, South Africa. Using a focus group guide, three focus group discussions were conducted. Data were analysed using the long-table approach ( Krueger and Casey, 2000 ). Trustworthiness of the study was ensured by following the criteria set out by Lincoln and Guba (1985) .

Findings: Five major themes related to nurses’ experiences of end-of-life care emerged. These included: “difficulties we experience”, “discussion and decision making”, “support for patients”, “support for families” and “support for nurses”.


Conclusion: End-of-life care can be difficult and a challenging process. Nevertheless, this study has highlighted some of the interventions and support systems that could be incorporated for improved caring process. Whereas the dying patients and their families need to be continuously supported, critical care nurses too need to be taken care of for them to continue providing the best possible end-of-life care.

Nutrition support practices in critically ill head-injured patients: a global perspective

Nutrition support practices in critically ill head-injured patients: a global perspective

Critical Care 2016 20:6 DOI: 10.1186/s13054-015-1177-1
Chapple L


Background: Critical illness following head injury is associated with a hypermetabolic state but there are insufficient epidemiological data describing acute nutrition delivery to this group of patients. Furthermore, there is little information describing relationships between nutrition and clinical outcomes in this population. Methods: We undertook an analysis of observational data, collected prospectively as part of International Nutrition Surveys 2007-2013, and extracted data obtained from critically ill patients with head trauma. Our objective was to describe global nutrition support practices in the first 12 days of hospital admission after head trauma, and to explore relationships between energy and protein intake and clinical outcomes. Data are presented as mean (SD), median (IQR), or percentages. Results: Data for 1045 patients from 341 ICUs were analyzed. The age of patients was 44.5 (19.7) years, 78 % were male, and median ICU length of stay was 13.1 (IQR 7.9-21.6) days. Most patients (94 %) were enterally fed but received only 58 % of estimated energy and 53 % of estimated protein requirements. Patients from an ICU with a feeding protocol had greater energy and protein intakes (p <0 .001="" 0.002="" 0.42-0.99="" 0.65="" 95="" a="" alive.="" alive="" all="" and="" are="" associated="" both="" ci="" commonplace="" conclusion:="" critically="" deficit="" deficits="" delay="" discharge="" energy="" from="" greater="" head-injured="" hospital="" however="" icu="" ill="" in="" intakes="" likely="" longer="" more="" mortality.="" not="" nutritional="" o:p="" or="" p="" patients="" protein="" respectively="" survive="" than="" these="" those="" times="" to="" until="" was="" were="" with="" without.="">

Safety and efficacy of prothrombin complex concentrate as first-line treatment in bleeding after cardiac surgery

Safety and efficacy of prothrombin complex concentrate as first-line treatment in bleeding after cardiac surgery
Critical Care 2016 20:5 DOI: 10.1186/s13054-015-1172-6
Cappabianca G, et al


Background: Bleeding after cardiac surgery requiring surgical reexploration and blood component transfusion is associated with increased morbidity and mortality. Although prothrombin complex concentrate (PCC) has been used satisfactorily in bleeding disorders, studies on its efficacy and safety after cardiopulmonary bypass are limited. Methods: Between January 2005 and December 2013, 3454 consecutive cardiac surgery patients were included in an observational study aimed at investigating the efficacy and safety of PCC as first-line coagulopathy treatment as a replacement for fresh frozen plasma (FFP). Starting in January 2012, PCC was introduced as solely first-line treatment for bleeding following cardiac surgery. Results: After one-to-one propensity score–matched analysis, 225 pairs of patients receiving PCC (median dose 1500 IU) and FFP (median dose 2 U) were included. The use of PCC was associated with significantly decreased 24-h post-operative blood loss (836 ± 1226 vs. 935 ± 583 ml, p < 0.0001). Propensity score–adjusted multivariate analysis showed that PCC was associated with significantly lower risk of red blood cell (RBC) transfusions (odds ratio [OR] 0.50; 95 % confidence interval [CI] 0.31–0.80), decreased amount of RBC units (β unstandardised coefficient −1.42, 95 % CI −2.06 to −0.77) and decreased risk of transfusion of more than 2 RBC units (OR 0.53, 95 % CI 0.38–0.73). Patients receiving PCC had an increased risk of post-operative acute kidney injury (AKI) (OR 1.44, 95 % CI 1.02–2.05) and renal replacement therapy (OR 3.35, 95 % CI 1.13–9.90). Hospital mortality was unaffected by PCC (OR 1.51, 95 % CI 0.84–2.72). Conclusions: In the cardiac surgery setting, the use of PCC compared with FFP was associated with decreased post-operative blood loss and RBC transfusion requirements. However, PCC administration may be associated with a higher risk of post-operative AKI.

Impact of prolonged assisted ventilation on diaphragmatic efficiency: NAVA versus PSV

Impact of prolonged assisted ventilation on diaphragmatic efficiency: NAVA versus PSV
Critical Care 2016 20:1
DOI: 10.1186/s13054-015-1178-0
Di mussi, R et al


Background: Prolonged controlled mechanical ventilation depresses diaphragmatic efficiency. Assisted modes of ventilation should improve it. We assessed the impact of pressure support ventilation versus neurally adjusted ventilator assist on diaphragmatic efficiency. MethodPatients previously ventilated with controlled mechanical ventilation for 72 hours or more were randomized to be ventilated for 48 hours with pressure support ventilation (n =12) or neurally adjusted ventilatory assist (n = 13). Neuro-ventilatory efficiency (tidal volume/diaphragmatic electrical activity) and neuro-mechanical efficiency (pressure generated against the occluded airways/diaphragmatic electrical activity) were measured during three spontaneous breathing trials (0, 24 and 48 hours). Breathing pattern, diaphragmatic electrical activity and pressure time product of the diaphragm were assessed every 4 hours. Results: In patients randomized to neurally adjusted ventilator assist, neuro-ventilatory efficiency increased and neuro-mechanical efficiency increased .
In patients randomized to pressure support ventilation, these did not change. Electrical activity of the diaphragm, neural inspiratory time, pressure time product of the diaphragm and variability of the breathing pattern were significantly higher in patients ventilated with neurally adjusted ventilatory assist. The asynchrony index was 9.48 [6.38– 21.73] in patients ventilated with pressure support ventilation and 5.39 [3.78– 8.36] in patients ventilated with neurally adjusted ventilatory assist (p = 0.04). Conclusion: After prolonged controlled mechanical ventilation, neurally adjusted ventilator assist improves diaphragm efficiency whereas pressure support ventilation does not.Trial registration ClinicalTrials.gov study registration: NCT0247317, 06/11/2015.