Marjolein de Wit

Ineffective triggering predicts increased duration of mechanical ventilation.

Objectives: To determine whether high rates of ineffective triggering within the first 24 hrs of mechanical ventilation (MV) are associated with longer MV duration and shorter ventilator‐free survival (VFS). Design: Prospective cohort study. Setting: Medical intensive care unit (ICU) at an academic medical center. Patients: Sixty patients requiring invasive MV. Interventions: None. Measurements: Patients had pressure‐time and flow‐time waveforms recorded for 10 mins within the first 24 hrs of MV initiation. Ineffective triggering index (ITI) was calculated by dividing the number of ineffectively triggered breaths by the total number of breaths (triggered and ineffectively triggered). A priori, patients were classified into ITI >=10% or ITI <10%. Patient demographics, MV reason, codiagnosis of chronic obstructive pulmonary disease (COPD), sedation levels, and ventilator parameters were recorded. Measurements and Main Results: Sixteen of 60 patients had ITI >=10%. The two groups had similar characteristics, including COPD frequency and ventilation parameters, except that patients with ITI >=10% were more likely to have pressured triggered breaths (56% vs. 16%, p = .003) and had a higher intrinsic respiratory rate (22 breaths/min vs. 18, p = .03), but the set ventilator rate was the same in both groups (9 breaths/min vs. 9, p = .78). Multivariable analyses adjusting for pressure triggering also demonstrated that ITI >=10% was an independent predictor of longer MV duration (10 days vs. 4, p = .0004) and shorter VFS (14 days vs. 21, p = .03). Patients with ITI >=10% had a longer ICU length of stay (8 days vs. 4, p = .01) and hospital length of stay (21 days vs. 8, p = .03). Mortality was the same in the two groups, but patients with ITI >=10% were less likely to be discharged home (44% vs. 73%, p = .04). Conclusions: Ineffective triggering is a common problem early in the course of MV and is associated with increased morbidity, including longer MV duration, shorter VFS, longer length of stay, and lower likelihood of home discharge.

Perceived barriers to the use of sedation protocols and daily sedation interruption: a multidisciplinary survey.

BACKGROUND Although use of sedation protocols and daily sedation interruption (DSI) improve outcome, their current use and barriers affecting their use are unclear. METHODS We designed a multidisciplinary, Web-based survey to determine current use of sedation protocols and DSI and the perceived barriers to each, and administered it to members of the Society of Critical Care Medicine. RESULTS The 904 responders were physicians (60%), nurses (14%), or pharmacists (12%); 45% worked in a university hospital. Of 64% having a sedation protocol, 78% used it for >or=50% of ventilated patients. Reasons for lack of protocol use included no physician order (35%), lack of nursing support (11%), and a fear of oversedation (7%). Daily sedation interruption was used by only 40%. Barriers to DSI included lack of nursing acceptance (22%), concern about risk of patient-initiated device removal (19%), and inducement of either respiratory compromise (26%) or patient discomfort (13%). Clinicians who prefer propofol were more likely to use DSI than those who prefer benzodiazepines (55% vs 40, P < .0001). CONCLUSIONS Current intensive care unit sedation practices are heterogeneous, and the barriers preventing the use of both sedation protocols and DSI are numerous. These barriers should be addressed on an institutional basis to boost the use of these evidence-based practices.

Growth in adult prolonged acute mechanical ventilation: implications for healthcare delivery.

Objective:Patients requiring prolonged acute mechanical ventilation (PAMV, defined as mechanical ventilation ≥96 hrs) have hospital survival rates similar to those requiring <96 hrs of mechanical ventilation and consume about two thirds of hospital resources devoted to mechanical ventilation care. Because of this disproportionate resource utilization and the shifting U.S. demographics, we projected the expected volume of adult PAMV cases through year 2020. Design:We used data from the National Inpatient Sample/Health Care Utilization Project of the Agency for Healthcare Research and Quality from 2000 to 2005 to calculate historic annual age-adjusted PAMV incidence rates using estimated population statistics from the U.S. Census Bureau. To predict future growth by age group, we fit linear regression models to the historic incidence rate changes. Age-adjusted estimates were computed using population projections obtained from the U.S. Census Bureau. Setting:U.S. hospitals. Patients:Nationally representative sample of U.S. hospital discharges with PAMV (code 96.72 from the International Classification of Diseases, Ninth Revision). Interventions:None. Measurements and Main Results:Historic annualized increase in PAMV was ∼5.5%, compared with ∼1% per annum growth in both U.S. population and hospital admissions. The fastest annualized growth was observed among 44–65 (7.9%) followed by 18–44 (4.7%), ≥85 (4.6%), and 65–84 (3.4%) age groups. Factoring in both age-specific growth in PAMV population and overall U.S. adult population changes, we project PAMV to more than double from approximately 250,000 cases in 2000 to 605,898 cases by year 2020. Conclusions:Patients undergoing PAMV are a large and resource-intensive population whose increase outpaces growth in the general U.S. population and in overall hospital volume. Policy makers must factor this projected rapid growth in frequency of PAMV into future resource and work force planning. Given the resource-intensive nature of these patients, strategies need to be developed to optimize their care and to increase efficiency of healthcare delivery to this large and growing population.

Randomized trial comparing daily interruption of sedation and nursing-implemented sedation algorithm in medical intensive care unit patients

IntroductionDaily interruption of sedation (DIS) and sedation algorithms (SAs) have been shown to decrease mechanical ventilation (MV) duration. We conducted a randomized study comparing these strategies.MethodsMechanically ventilated adults 18 years old or older in the medical intensive care unit (ICU) were randomly assigned to DIS or SA. Exclusion criteria were severe neurocognitive dysfunction, administration of neuromuscular blockers, and tracheostomy. Study endpoints were total MV duration and 28-day ventilator-free survival.ResultsThe study was terminated prematurely after 74 patients were enrolled (DIS 36 and SA 38). The two groups had similar age, gender, racial distribution, Acute Physiology and Chronic Health Evaluation II score, and reason for MV. The Data Safety Monitoring Board convened after DIS patients were found to have higher hospital mortality; however, no causal connection between DIS and increased mortality was identified. Interim analysis demonstrated a significant difference in primary endpoint, and study termination was recommended. The DIS group had longer total duration of MV (median 6.7 versus 3.9 days; P = 0.0003), slower improvement of Sequential Organ Failure Assessment over time (0.70 versus 0.23 units per day; P = 0.025), longer ICU length of stay (15 versus 8 days; P < 0.0001), and longer hospital length of stay (23 versus 12 days; P = 0.01).ConclusionIn our cohort of patients, the use of SA was associated with reduced duration of MV and lengths of stay compared with DIS. Based on these results, DIS may not be appropriate in all mechanically ventilated patients.Trial registrationClinicalTrials.gov NCT00205517.

Observational study of patient-ventilator asynchrony and relationship to sedation level.

PURPOSE Clinicians frequently administer sedation to facilitate mechanical ventilation. The purpose of this study was to examine the relationship between sedation level and patient-ventilator asynchrony. MATERIALS AND METHODS Airway pressure and airflow were recorded for 15 minutes. Patient-ventilator asynchrony was assessed by determining the number of breaths demonstrating ineffective triggering, double triggering, short cycling, and prolonged cycling. Ineffective triggering index (ITI) was calculated by dividing the number of ineffectively triggered breaths by the total number of breaths (triggered and ineffectively triggered). Sedation level was assessed by the following 3 methods: Richmond Agitation-Sedation Scale (RASS), awake (yes or no), and delirium (Confusion Assessment Method for the intensive care unit [CAM-ICU]). RESULTS Twenty medical ICU patients underwent 35 observations. Ineffective triggering was seen in 17 of 20 patients and was the most frequent asynchrony (88% of all asynchronous breaths), being observed in 9% +/- 12% of breaths. Deeper levels of sedation were associated with increasing ITI (awake, yes 2% vs no 11%; P < .05; CAM-ICU, coma [15%] vs delirium [5%] vs no delirium [2%]; P < .05; RASS, 0, 0% vs -5, 15%; P < .05). Diagnosis of chronic obstructive pulmonary disease, sedative type or dose, mechanical ventilation mode, and trigger method had no effect on ITI. CONCLUSIONS Asynchrony is common, and deeper sedation level is a predictor of ineffective triggering.

Alcohol-Use Disorders in the Critically Ill Patient

Alcohol abuse and dependence, referred to as alcohol-use disorders (AUDs), affect 76.3 million people worldwide and account for 1.8 million deaths per year. AUDs affect 18.3 million Americans (7.3% of the population), and up to 40% of hospitalized patients have AUDs. This review discusses the development and progression of critical illness in patients with AUDs. In contrast to acute intoxication, AUDs have been linked to increased severity of illness in a number of studies. In particular, surgical patients with AUDs experience higher rates of postoperative hemorrhage, cardiac complications, sepsis, and need for repeat surgery. Outcomes from trauma are worse for patients with chronic alcohol abuse, whereas burn patients who are acutely intoxicated may not have worse outcomes. AUDs are linked to not only a higher likelihood of community-acquired pneumonia and sepsis but also a higher severity of illness and higher rates of nosocomial pneumonia and sepsis. The management of sedation in patients with AUDs may be particularly challenging because of the increased need for sedatives and opioids and the difficulty in diagnosing withdrawal syndrome. The health-care provider also must be watchful for the development of dangerous agitation and violence, as these problems are not uncommonly seen in hospital ICUs. Despite studies showing that up to 40% of hospitalized patients have AUDs, relatively few guidelines exist on the specific management of the critically ill patient with AUDs. AUDs are underdiagnosed, and a first step to improving patient outcomes may lie in systematically and accurately identifying AUDs.

Accuracy of previous estimates for adult prolonged acute mechanical ventilation volume in 2020: update using 2000-2008 data.

Objectives:Patients requiring prolonged acute mechanical ventilation (mechanical ventilation ≥96 hrs) have hospital survival rates similar to those requiring <96 hrs of mechanical ventilation and consume approximately two-thirds of hospital resources devoted to mechanical ventilation care. Using 2000–2005 data, we previously estimated that their volume will go from approximately 250,000 cases in 2000 to 605,898 by year 2020. With 2006–2008 data becoming available, we explored the precision of our previous formulas and estimates. Design:We utilized National Inpatient Sample/Health Care Utilization Project of the Agency for Healthcare Research and Quality data from 2000 to 2008 to calculate historic annual age-adjusted prolonged acute mechanical ventilation incidence rates using estimated population statistics from the U.S. Census Bureau. To predict future growth by age group, we fit linear regression models to the historic incidence rate changes. Age-adjusted estimates were computed using population projections obtained from the U.S. Census Bureau. Setting:U.S. hospitals. Patients:Nationally representative sample of U.S. hospital discharges with prolonged acute mechanical ventilation (International Classification of Diseases version 9 code 96.72). Interventions:None. Measurements and Main Results:Formulas based on the 2000–2005 data predicted the 2008 prolonged acute mechanical ventilation volume within a 1.9% margin. The historic annualized increase in adult prolonged acute mechanical ventilation increased from 5.0% to 5.2% after incorporating the 2006–2008 data. Factoring in the 2006–2008 data altered our 2020 prolonged acute mechanical ventilation estimates from 605,898 (95% confidence interval 456,695–779,806) to 625,298 (95% confidence interval 552,168–698,838), an upward revision of 3.2%. Conclusion:Our original projections for growth of the adult prolonged acute mechanical ventilation population in the U.S. hospitals by the year 2020 are altered only slightly by adding the 2006–2008 data. Relatively precise prediction of the 2008 prolonged acute mechanical ventilation numbers by the original formulas lends internal validity to the methodology. By virtue of being a large, resource-intensive, and rapidly increasing population, this group of mechanical ventilation patients requires continued close monitoring over time to optimize our preparedness to meet their growing healthcare needs.

Prevalence and impact of alcohol and other drug use disorders on sedation and mechanical ventilation: a retrospective study

BackgroundExperience suggests that patients with alcohol and other drug use disorders (AOD) are commonly cared for in our intensive care units (ICUs) and require more sedation. We sought to determine the impact of AOD on sedation requirement and mechanical ventilation (MV) duration.MethodsRetrospective review of randomly selected records of adult patients undergoing MV in the medical ICU. Diagnoses of AOD were identified using strict criteria in Diagnostic and Statistical Manual of Mental Disorders, and through review of medical records and toxicology results.ResultsOf the 70 MV patients reviewed, 27 had AOD (39%). Implicated substances were alcohol in 22 patients, cocaine in 5, heroin in 2, opioids in 2, marijuana in 2. There was no difference between AOD and non-AOD patients in age, race, or reason for MV, but patients with AOD were more likely to be male (21 versus 15, p < 0.0001) and had a lower mean Acute Physiology and Chronic Health Evaluation II (22 versus 26, p = 0.048). While AOD patients received more lorazepam equivalents (0.5 versus 0.2 mg/kg.day, p = 0.004), morphine equivalents (0.5 versus 0.1 mg/kg.day, p = 0.03) and longer duration of infusions (16 versus 10 hours/day. medication, p = 0.002), they had similar sedation levels (Richmond Agitation-Sedation Scale (RASS) -2 versus -2, p = 0.83), incidence of agitation (RASS ≥ 3: 3.0% versus 2.4% of observations, p = 0.33), and duration of MV (3.6 versus 3.9 days, p = 0.89) as those without AOD.ConclusionThe prevalence of AOD among medical ICU patients undergoing MV is high. Patients with AOD receive higher doses of sedation than their non-AOD counterparts to achieve similar RASS scores but do not undergo longer duration of MV.

Monitoring of Patient-Ventilator Interaction at the Bedside

Monitoring of patient-ventilator interactions at the bedside involves evaluation of patient breathing pattern on ventilator settings. One goal of mechanical ventilation is to have ventilator-assisted breathing coincide with patient breathing. The objectives of this goal are to have patient breath initiation result in ventilator triggering without undue patient effort, to match assisted-breath delivery with patient inspiratory effort, and to have assisted breathing cease when the patient terminates inspiration, thus avoiding ventilator-assisted inspiration during patient exhalation. Asynchrony can occur throughout the respiratory cycle, and this paper describes common asynchronies. The types of asynchronies discussed are trigger asynchrony (ie, breath initiation that may manifest as ineffective triggering, double-triggering, or auto-triggering); flow asynchrony (ie, breath-delivery asynchrony, which may manifest as assisted-breath delivery being faster or slower than what patient desires); and cycling asynchronies (ie, termination of assisted inspiration does not coincide with patient breath termination, which may manifest as delayed cycling or premature cycling). Various waveforms are displayed and graphically demonstrate asynchronies; basic principles of waveform interpretation are discussed.

Health care-associated infections in surgical patients undergoing elective surgery: are alcohol use disorders a risk factor?

BACKGROUND Health care-associated infections (HAI) result in 100,000 deaths/year. Alcohol use disorders (AUD) increase the risk of community-acquired infections and HAI. Small studies have shown that AUD increase the risk of HAI and surgical site infections (SSI). We sought to determine the risk of HAI and SSI in surgical patients undergoing elective inpatient joint replacement, coronary artery bypass grafting, laparoscopic cholecystectomy, colectomy, and hernia repair. STUDY DESIGN The Nationwide Inpatient Sample was analyzed (years 2007 and 2008). HAI were defined as health care-associated pneumonia, sepsis, SSI, and urinary tract infection. Primary outcomes were risk of HAI and SSI in patients with AUD. Secondary outcomes were mortality and hospital length of stay in patients with HAI and SSI, alpha = 10(-6). RESULTS There were 1,275,034 inpatient admissions analyzed; 38,335 (3.0%) cases of HAI were documented, and 5,756 (0.5%) cases of SSI were identified. AUD was diagnosed in 11,640 (0.9%) of cases. Multivariable analysis demonstrated that AUD was an independent predictor of developing HAI: odds ratio (OR) 1.70, p < 10(-6), and this risk was independent of type of surgery. By multivariable analysis, the risk of SSI in patients with AUD was also higher: OR 2.73, p < 10(-6). Hospital mortality in patients with HAI or SSI was not affected by AUD. However, hospital length of stay was longer in patients with HAI who had AUD (multivariable analysis 2.4 days longer, p < 10(-6)). Among patients with SSI, those with AUD did not have longer hospital length of stay. CONCLUSIONS Patients with AUD who undergo a variety of elective operations have an increased risk of infectious postoperative morbidity.