COMBED: Rapid non-invasive Cardiac Output Monitoring Baseline assessment in adult Emergency Department patients with haemodynamic instability.

OBJECTIVE: The application of rapid, non-operator-dependent, non-invasive cardiac output monitoring (COM) may provide early physiological information in ED patients with haemodynamic instability (HI). Our primary objective was to assess the feasibility of measuring pre-intervention (baseline) cardiac index (CI) and associated haemodynamic parameters. METHODS: We performed a prospective observational study of adults shortly after presentation to the ED of a large university hospital with tachycardia or hypotension or both. We applied non-invasive COM for 5 min and recorded CI, mean arterial pressure (MAP), stroke volume index (SVI) and systemic vascular resistance index (SVRI). We assessed for differences between those presenting with hypotension or hypotension and tachycardia with tachycardia alone and between those with or without suspected infection. RESULTS: We obtained haemodynamic parameters in 46 of 49 patients. In patients with hypotension or hypotension and tachycardia (n = 15) rather than tachycardia alone (n = 31), we observed a lower MAP (60.8 vs 87.7, P < 0.0001), CI (2.8 vs 3.9, P = 0.0167) and heart rate (85.5 vs 115.4, P < 0.0001). There was no difference in SVI (33.7 vs 33.4, P = 0.93) or SVRI (1970 vs 2088, P = 0.67). Patients with suspected infection had similar haemodynamic values except for a lower SVRI (1706 vs 2237, P = 0.011). CONCLUSIONS: Rapid, non-operator-dependent, non-invasive COM was possible in >90% of ED patients presenting with HI. Compared with tachycardia alone, patients with hypotension had lower CI, MAP and heart rate, while those with suspected infection had a lower SVRI. This technology provides novel insights into the early state of the circulation in ED patients with HI.

Rapid response team review of hemodynamically unstable ward patients: The accuracy of cardiac index assessment.

PURPOSE: Intensive care doctors commonly attend rapid response team (RRT) reviews of hospital-ward patients with hemodynamic instability and estimate the patient's likely cardiac index (CI). We aimed to non-invasively measure the CI of such patients and assess the level of agreement between such measurements and clinically estimated CI categories (low <2L/min/m2, normal 2-2.99L/min/m2 or high ≥3L/min/m2). MATERIALS AND METHODS: A prospective, observational study of non-invasive measurement and clinical estimation of CI categories in 50 adult hospital-ward patients who activated the RRT for 'hemodynamic instability' (tachycardia > 100BPM or hypotension < 90mmHg or both). RESULTS: The CI was measured in 47/50(94%) patients and the mean CI was 3.5(95% CI 3.2-3.7) L/min/m2. Overall, 30(64%) patients had a high CI, 13(28%) and 4(9%) had a normal and a low CI, respectively. The level of agreement between measured and clinically estimated CI categories was low(19.2%). Sensitivity and positive predictive values of clinical estimation were low(0% and 3.3% for high CI, and 0% and 50% for low CI, respectively). CONCLUSIONS: Non-invasive CI measurement was possible in almost all hospital-ward patients triggering RRT review for hemodynamic instability. In such patients, the CI was high, and intensive care clinicians were unable to identify a low or a high CI state.

Prevalence of ketosis, ketonuria, and ketoacidosis during liberal glycemic control in critically ill patients with diabetes: an observational study.

BACKGROUND: It is uncertain whether liberal glucose control in critically ill diabetic patients leads to increased ketone production and ketoacidosis. Therefore, we aimed to assess the prevalence of ketosis, ketonuria and ketoacidosis in critically ill diabetic patients treated in accordance with a liberal glycemic control protocol. METHODS: We performed a prospective observational cohort study of 60 critically ill diabetic patients with blood and/or urine ketone bodies tested in ICU. All patients were treated according to a liberal glucose protocol targeting a blood glucose level (BGL) between 10 and 14 mmol/l in a single tertiary intensive care unit in Australia. We measured quantitative bedside blood 3-beta-hydroxybutyrate (ß-OHB) and semi-quantitative urine ketones on ICU admission and daily during ICU stay, for a maximum of 10 consecutive days. RESULTS: Median blood ß-OHB level on admission was 0.3 (0.1, 0.8) mmol/l. Ketoacidosis was rare (3 %), but some level of ketosis (ß-OHB ≥0.6 mmol/l) was found in 38 patients (63 %) early during their ICU stay. However, there was no significant difference in prevalence or severity of ketonemia and ketonuria among patients with BGL above (permissive hyperglycemia) or below 10 mmol/l. On multivariable linear regression analysis there was no association between blood ketone levels and BGL, HbA1c, lactate levels, hematocrit, catecholamine infusion or APACHE III score. In contrast, blood ketone levels tended to be higher after cardiopulmonary bypass surgery (P = 0.06). CONCLUSIONS: Liberal glycemic control in critically ill diabetic patients does not appear to be associated with a high prevalence of ketoacidosis or ketonemia. Moreover, ketosis is typically present on admission and resolves rapidly. Finally, cardiopulmonary bypass surgery may be an important trigger of ketone body production. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ( ACTRN12615000216516 ; trial registration date 5 March 2015).

Liberal Versus Conventional Glucose Targets in Critically Ill Diabetic Patients: An Exploratory Safety Cohort Assessment.

OBJECTIVES: To assess the feasibility, safety, and impact on relative hypoglycemia of liberal versus conventional blood glucose concentration targets in critically ill diabetic patients. DESIGN: Prospective, open-label, sequential-period exploratory study. SETTING: A 22-bed multidisciplinary ICU of a tertiary care hospital in Australia. PATIENTS: Eighty adult diabetic patients, 40 from the conventional before period and 40 from the liberal after period. INTERVENTIONS: Blood glucose concentration targets were 6-10 mmol/L during the before period and 10-14 mmol/L during the after period. MEASUREMENTS AND MAIN RESULTS: We used admission glycated hemoglobin to estimate premorbid baseline blood glucose concentration. We defined glycemic distance as the difference between blood glucose concentration in ICU and baseline blood glucose concentration. During the first 48 ICU hours, we recorded absolute (blood glucose concentration, < 3.9 mmol/L) and relative (glycemic distance, > 30% below baseline) hypoglycemia rates, insulin administration, and outcomes. The groups had similar baseline characteristics. We observed a negative glycemic distance in 248 of 488 blood glucose concentrations (50.8%) during the before period and 164 of 485 (33.8%) during the after period (p < 0.001). We detected relative hypoglycemia in 20 (50.0%) and nine (22.5%) patients in the before and after periods, respectively (p = 0.01). On day 1, 50.0% and 16.7% received insulin in the before and after periods (p = 0.007). ICU and hospital length of stay and mortality were similar between groups. CONCLUSIONS: In a safety cohort of critically ill diabetic patients, a blood glucose concentration target of 10-14 mmol/L resulted in fewer episodes of negative glycemic distance or relative hypoglycemia and reduced insulin administration compared with a target of 6-10 mmol/L.

Validation of a classification system for causes of death in critical care: an assessment of inter-rater reliability.

OBJECTIVE: Trials in critical care have previously used unvalidated systems to classify cause of death. We aimed to provide initial validation of a method to classify cause of death in intensive care unit patients. DESIGN, SETTING AND PARTICIPANTS: One hundred case scenarios of patients who died in an ICU were presented online to raters, who were asked to select a proximate and an underlying cause of death for each, using the ICU Deaths Classification and Reason (ICU-DECLARE) system. We evaluated two methods of categorising proximate cause of death (designated Lists A and B) and one method of categorising underlying cause of death. Raters were ICU specialists and research coordinators from Australia, New Zealand and the United Kingdom. MAIN OUTCOME MEASURES: Inter-rater reliability, as measured by the Fleiss multirater kappa, and the median proportion of raters choosing the most likely diagnosis (defined as the most popular classification choice in each case). RESULTS: Across all raters and cases, for proximate cause of death List A, kappa was 0.54 (95% CI, 0.49-0.60), and for proximate cause of death List B, kappa was 0.58 (95% CI, 0.53-0.63). For the underlying cause of death, kappa was 0.48 (95% CI, 0.44-0.53). The median proportion of raters choosing the most likely diagnosis for proximate cause of death, List A, was 77.5% (interquartile range [IQR], 60.0%-93.8%), and the median proportion choosing the most likely diagnosis for proximate cause of death, List B, was 82.5% (IQR, 60.0%-92.5%). The median proportion choosing the most likely diagnosis for underlying cause was 65.0% (IQR, 50.0%-81.3%). Kappa and median agreement were similar between countries. ICU specialists showed higher kappa and median agreement than research coordinators. CONCLUSIONS: The ICU-DECLARE system allowed ICU doctors to classify the proximate cause of death of patients who died in the ICU with substantial reliability.

Nasal high-flow oxygen therapy in ICU: A before-and-after study.

BACKGROUND: Non-intubated intensive care patients commonly receive supplemental oxygen by high-flow face mask (HFFM), simple face mask (FM) and nasal prongs (NP) during their ICU admission. However, high-flow nasal prongs (HFNP) offer considerable performance capabilities that may sufficiently meet all their oxygen therapy requirements. STUDY AIMS: To assess the feasibility, safety and cost-effectiveness of introducing a protocol in which HFNP was the primary oxygen delivery device for non-intubated intensive care patients. METHOD: Prospective 4-week before-and-after study (6 months apart) for all adult patients admitted to a 22-bed tertiary ICU in Melbourne, Australia. RESULTS: 117 patients (57 before, 60 after) were included: 86 (73.5%) received mechanical ventilation. Feasibility revealed a significant reduction in HFFM (52.6-0%, p<.001), FM (35.1-8.3%, p=.002) and NP (75.4-36.7%, p<.001) use and an increase in HFNP use (31.6-81.7%, p<.05) during the after period. Following extubation, there was a significant reduction in HFFM use (65.7% vs. 0%, p<.05) and an increase HFNP use (8.6% vs. 87.5%, p<.05). Costing was in favour of the after period with a consumable cost saving per patient (AUD $32.56 vs. $17.62, p<.05). During the after period, more patients were discharged from ICU with HFNP than during the before period (5 vs. 33 patients, p<.05) and fewer patients (5 vs. 14 patients) used three or more oxygen delivery devices. Safety outcomes demonstrated no significant difference in the number of intubations, re-intubations, readmissions or non-invasive ventilation use between the two time periods. CONCLUSIONS: Using HFNP as the primary oxygen delivery method for non-intubated intensive care patients was feasible, appeared safe, and the oxygen device costs were reduced. The findings of our single-centre study support further multi-centre evaluations of HFNP therapy protocols in non-ventilated intensive care patients.

A Pilot Assessment of Carotid and Brachial Artery Blood Flow Estimation Using Ultrasound Doppler in Cardiac Surgery Patients.

OBJECTIVES: To estimate carotid and brachial artery blood flow with Doppler ultrasound in cardiac surgery patients and relate such estimates to cardiac index, lactate levels, and markers of renal function. DESIGN: A prospective observational study. SETTING: A teaching hospital. PARTICIPANTS: Twenty-five elective cardiac surgery patients. INTERVENTIONS: The authors measured bilateral carotid and brachial artery blood flows using Doppler ultrasound and, simultaneously, cardiac index using a pulmonary artery catheter; lactate and serum creatinine levels; and urine output. The relationship between these indices and biomarkers was assessed statistically. MEASUREMENTS AND MAIN RESULTS: Median carotid arterial blood flow was estimated at 0.323 L/min (interquartile ratio [IQR], 0.256-0.429 L/min) on the right and 0.308 L/min (IQR, 0.247-0.376 L/min) on the left at baseline. Median brachial arterial blood flow was estimated at 0.063 L/min (IQR, 0.039-0.115 L/min) on the right and 0.063 L/min (IQR, 0.039-0.081 L/min) on the left at baseline. There was a weak correlation between right- and left-sided flows (brachial: rho = 0.285; carotid: rho = 0.384) and between brachial and carotid flow (right: rho = 0.135, left: rho = 0.225). There also was a weak correlation between cardiac index and brachial flow (right: rho = 0.215; left: rho = 0.320) and carotid flow (left: rho = 0.159) immediately after surgery, and no correlation 1 day after surgery (right brachial: rho = -0.010; left brachial: rho = -0.064; left carotid: rho = -0.060). There were no significant correlations between carotid or brachial flows and lactate and serum creatinine levels or urine output. CONCLUSIONS: In cardiac surgery patients, Doppler-estimated carotid and brachial arterial blood flows have only a weak correlation with cardiac index and no correlation with lactate or creatinine levels or urine output. Thus, Doppler estimation of these blood flows cannot be used to provide noninvasive estimates of cardiac index in patients after cardiac surgery.

A pilot assessment of alpha-stat vs pH-stat arterial blood gas analysis after cardiac arrest.

PURPOSE: Resuscitated cardiac arrest (CA) patients typically receive therapeutic hypothermia, but arterial blood gases (ABGs) are often assessed after adjustment to 37°C (alpha-stat) instead of actual body temperature (pH-stat). We sought to compare alpha-stat and pH-stat assessment of PaO2 and PaCO2 in such patients. MATERIALS AND METHODS: Using ABG data obtained during the first 24 hours of intensive care unit admission, we determined the impact of measured alpha vs calculated pH-stat on PaO2 and PaCO2 on patient classification and outcomes for CA patients. RESULTS: We assessed 1013 ABGs from 120 CA patients with a median age of patients 66 years (interquartile range, 50-76). Median alpha-stat PaO2 changed from 122 (95-156) to 107 (82-143) mm Hg with pH-stat and median PaCO2 from 39 (34-46) to 35 (30-41) mm Hg (both P < .001). Using the categories of hyperoxemia, normoxemia, and hypoxemia, pH-stat estimation of PaO2 reclassified approximately 20% of patients. Using the categories of hypercapnia, normocapnia, and hypocapnia, pH stat estimation of PaCO2 reclassified approximately 40% of patients. The mortality of patients in different PaO2 and PaCO2 categories was similar for pH-stat and alpha-stat. CONCLUSIONS: Using the pH-stat method, fewer resuscitated CA patients admitted to intensive care unit were classified as hyperoxemic or hypercapnic compared with alpha-stat. These findings suggest an impact of ABG assessment methodology on PaO2, PaCO2 , and patient classification but not on associated outcomes.

High cut-off hemofiltration versus standard hemofiltration: a pilot assessment of effects on indices of apoptosis.

OBJECTIVES: To measure plasma pro-apoptotic and pro-necrotic activity in severe acute kidney injury (AKI) patients within a randomized controlled trial of continuous veno-venous hemofiltration with high cut-off filters (CVVH-HCO) versus standard filters (CVVH-Std). METHODS: We measured pro-apoptotic and pro-necrotic plasma activity by trypan blue exclusion cell viability assay, detection of DNA fragmentation, and by determination of caspase-3 activity and annexin V-based apoptosis and necrosis detection assay. RESULTS: Compared to no apoptosis or necrosis after incubation with healthy plasma, 14-18% of cells showed apoptosis and 4-8% showed necrosis after incubation with plasma from AKI patients. When comparing different measures of pro-apoptotic or pro-necrotic activity, CVVH-HCO and CVVH-Std showed no differential effects on such activity, which remained high over the first 3 days of treatment. However, using annexin V-FITC, there was a significant drop in pro-apoptotic activity across the filter for the CVVH-HCO group (p = 0.043) but not for the CVVH-Std group (p = 0.327) and a significant difference between the two groups (CVVH-HCO vs. CVVH-Std p = 0.006). CONCLUSIONS: Patients with severe AKI have increased pro-apoptotic and pro-necrotic activity. Although on single-pass effect assessment, CVVH-HCO was superior to CVVH-Std in decreasing annexin V-FITC-assessed pro-apoptotic activity, there was no overall attenuation of such activity during the first 3 days of treatment.

Improving communication of the daily care plan in a teaching hospital intensive care unit.

BACKGROUND: Patients admitted to intensive care units have complex care needs. Accordingly, communication and handover of the medical care plan is very important. OBJECTIVE: To assess changes in ICU nurses' understanding of the medical daily care plan after development and implementation of a pro forma to improve documentation and communication of the plan. DESIGN, SETTING AND PARTICIPANTS: The study was conducted between February and November 2012 in a mixed medical-surgical, 18-bed, closed ICU in a teaching hospital. Baseline and post-intervention surveys assessed ICU bedside nurses' self-reported understanding of elements of the daily care plan. INTERVENTION: After receiving input from bedside nurses and medical staff, we developed the daily care plan as a single-page pro forma for handwritten documentation of a clinical problems list, plan and interventions list, daily chest x-ray results, a modified FAST-HUG checklist, and discharge planning during the evening consultant ward round. The finalised pro forma was introduced on 25 July 2012. RESULTS: Introduction of the pro forma daily care plan was associated with marked and statistically significant improvements in nurses' self-reported understanding of a list of the patient's clinical problems, the management plan after the ward round, issues for discharge for the following day (all P < 0.001) and, to a lesser extent, the physiological targets and aims (P = 0.003) and interpretation of the daily chest x-ray (P < 0.001). In the post-intervention survey, only 4/118 free-text comments (3.4%) suggested that documentation of the plan was doctor-dependent, compared with 28/198 (14.1%) at baseline (P = 0.002). CONCLUSIONS: Introduction of a single-page, handwritten, structured daily care plan produced marked improvements in ICU nurses' self-reported understanding of elements of the medical plan, and may have reduced practice variation in medical plan documentation. The effects of this intervention on patient outcomes remain untested.

A questionnaire survey of critical care nurses' attitudes to delirium assessment before and after introduction of the CAM-ICU.

BACKGROUND: Nurses are usually the first to identify delirium in ICU patients. We aimed to assess the attitudes of Australian critical care nurses when we introduced the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU). METHODS: We surveyed all 174 nurses in our ICU using two questionnaires: first after a one-month period of mandated but unstructured delirium assessments, and then following one month of CAM-ICU assessments. We also quantified antipsychotic medication usage by inspecting pharmacy records. FINDINGS: The first survey response rate was 65/174 (37%). Most nurses (73%) thought active delirium assessment was important, and 93% thought their assessments were worth the time required. These assessments were largely unstructured, as only 20% knew a formal delirium test, and only 7% sometimes used one. The second survey response rate was 45/174 (26%). Most (89%) still thought delirium assessment was important, but only 75% thought the CAM-ICU worth the time required (p=0.01 compared to unstructured assessments). Similar proportions (75% and 73%) were confident in the accuracy of their assessments. Many (33%) found the CAM-ICU 'quite' or 'very' hard to perform, but despite this, 82% wanted to continue to use it. Free-text answers suggested this was because medical staff paid more attention to the CAM-ICU. Supporting this, prescriptions of antipsychotic medications increased significantly in the CAM-ICU period. CONCLUSION: Critical care nurses in our Australian ICU who responded to our survey think delirium assessment is important. Although they find unstructured assessments easier to perform, they wanted to persist with the CAM-ICU, in part because it facilitated more appropriate pharmacological treatment of delirium for their patients. We recommend the CAM-ICU as a tool to improve communication between nurses and physicians in the management of delirium.

Routine use of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) by bedside nurses may underdiagnose delirium.

BACKGROUND: The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is emerging as the most frequently used tool for identifying delirium among critically ill patients. OBJECTIVE: To determine whether the number of patients and nursing shifts in which delirium was diagnosed would increase after the introduction of the CAM-ICU in our unit. DESIGN: Before-and-after study. In a 30-day Phase 1, we asked bedside nurses to assess their ICU patients for delirium each shift. We then conducted intensive education on the CAM-ICU for 30 days, including lectures, bedside tutorials, and supervised practice. In Phase 2, for 30 days we asked bedside nurses to record the results of their CAM-ICU assessments. SETTING: 20-bed mixed medical and surgical ICU at the Austin Hospital, Melbourne. PARTICIPANTS: All patients admitted to the ICU during each phase. MAIN OUTCOME MEASURES: Diagnosis of delirium by bedside nurses using either the CAM-ICU or an unstructured clinical assessment, by patient and nursing shift. RESULTS: Compared with unstructured assessments, the CAM-ICU identified a significantly lower proportion of patients (36.7% v 21.3%; P = 0.004) and a significantly lower proportion of shifts (14.7% v 6.4% of shifts, P = 0.002) with delirium. When adjusted for differences in age, sex, Acute Physiology and Chronic Health Evaluation III risk of death and total length of stay between the two periods, assessment type remained a significant predictor of the diagnosis of delirium. CONCLUSIONS: In our hospital, the CAM-ICU detected delirium less often than unstructured delirium assessments made by qualified intensive care nurses.