Definition of hourly urine output influences reported incidence and staging of acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is commonly defined using the KDIGO system, which includes criteria based on reduced urine output (UO). There is no consensus on whether UO should be measured using consecutive hourly readings or mean output. This makes KDIGO UO definition and staging of AKI vulnerable to inconsistency which has implications both for research and clinical practice. The objective of this study was to investigate whether the way in which UO is defined affects incidence and staging of AKI. METHODS: We conducted a retrospective analysis of two single centre observational studies investigating (i) patients undergoing cardiac surgery and (ii) patients admitted to general intensive care units (ICU). AKI was identified using KDIGO serum creatinine (SCr) criteria and two methods of UO (UOcons: UO meeting KDIGO criteria in each consecutive hour; UOmean: mean hourly UO meeting KDIGO criteria). RESULTS: Data from 151 CICU and 150 ICU admissions were analysed. Incidence of AKI using SCr alone was 23.8% in CICU and 32% in ICU. Incidence increased in both groups when UO was considered, with inclusion of UOmean more than doubling reported incidence of AKI (CICU: UOcons 39.7%, UOmean 72.8%; ICU: UOcons 51.3%, UOmean 69.3%). In both groups UOcons led to a larger increase in KDIGO stage 1 but UOmean increased the incidence of KDIGO stage 2. CONCLUSIONS: We demonstrate a serious lack of clarity in the internationally accepted AKI definition leading to significant variability in reporting of AKI incidence.

Tricuspid Annular Plane Systolic Excursion: Comparing Transthoracic to Transesophageal Echocardiography.

OBJECTIVE: Tricuspid annular plane systolic excursion (TAPSE) represents movement of the lateral annulus of the tricuspid valve toward the apex and denotes right ventricular contractility in the long axis. In transesophageal echocardiography with the probe in the mid-esophagus, TAPSE occurs at a significant angle to the M-mode scan line. The authors describe a novel method to assess TAPSE in 2 dimensions (2D) and compare this with an established method. DESIGN: Prospective cohort study. SETTING: Tertiary cardiac unit. PARTICIPANTS: Forty-three patients scheduled for outpatient transesophageal echocardiography. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: TAPSE was assessed from the transthoracic apical window using M-mode (M-TAPSE) and the mid-esophageal 4-chamber view (2D-TAPSE). To assess 2D-TAPSE, the authors placed an annotation arrow at the junction of the tricuspid annulus and right ventricular free wall during diastole, and a second arrow at this junction at end-systole; 2D-TAPSE represented the distance between the arrows. The mean M-TAPSE was 20.5 (5.9) mm and 2D-TAPSE was 20.5 (5.8) mm. The mean angle between the direction of the lateral tricuspid annular motion and the M-mode scan line from the transthoracic apical window was 19.4 (7.6) degrees and from the mid-esophageal 4-chamber view 62.6 (15.7) degrees (p<0.001). There was a close correlation between M-TAPSE and 2D-TAPSE; r2 = 0.93. Ninety-five percent of 2D-TAPSE were -3.2mm to+3.1mm of M-TAPSE (95% confidence interval -4.0 mm to+4.0 mm). The positive predictive value of 2D-TAPSE<17 mm to predict M-TAPSE<17 was 83%. The negative predictive value of 2D-TAPSE≥17 mm to predict M-TAPSE≥17 was 93%. The intra- and inter-observer variability for 2D-TAPSE was 6.7% and 9.7%, respectively. CONCLUSIONS: Transesophageal 2D-TAPSE appeared to be a reliable and simple method to assess right ventricular function, and demonstrated a close correlation with transthoracic M-TAPSE.

Focused transoesophageal TOE (fTOE): A new accreditation pathway.

The concept of a focused ultrasound study to identify sources of haemodynamic instability has revolutionized patient care. Point-of-care ultrasound (POCUS) using transthoracic scanning protocols, such as FUSIC Heart, has empowered non-cardiologists to rapidly identify and treat the major causes of haemodynamic instability. There are, however, circumstances when a transoesphageal, rather than transthoracic approach, may be preferrable. Due to the close anatomical proximity between the oesophagus, stomach and heart, a transoesphageal echocardiogram (TOE) can potentially overcome many of the limitations encountered in patients with poor transthoracic ultrasound windows. These are typically patients with severe obesity, chest wall injuries, inability to lie in the left lateral decubitus position and those receiving high levels of positive airway pressure. In 2022, to provide all acute care practitioners with the opportunity to acquire competency in focused TOE, the Intensive Care Society (ICS) and Association of Anaesthetists (AA) launched a new accreditation pathway, known as Focused Transoesophageal Echo (fTOE). The aim of fTOE is to provide the practitioner with the necessary information to identify the aetiology of haemodynamic instability. Focused TOE can be taught in a shorter period of time than comprehensive and teaching programmes are achievable with support from cardiothoracic anaesthetists, intensivists and cardiologists. Registration for fTOE accreditation requires registration via the ICS website. Learning material include theoretical modules, clinical cases and multiple-choice questions. Fifty fTOE examinations are required for the logbook, and these must cover a range of pathology, including ventricular dysfunction, pericardial effusion, tamponade, pleural effusion and low preload. The final practical assessment may be undertaken when the supervisors deem the candidate's knowledge and skills consistent with that required for independent practice. After the practitioner has been accredited in fTOE, they must maintain knowledge and competence through relevant continuing medical education. Accreditation in fTOE represents a joint venture between the ICS and AA and is endorsed by Association of Cardiothoracic Anaesthesia and Critical care (ACTACC). The process is led by TOE experts, and represents a valuable expansion in the armamentarium of acute care practitioners to assess haemodynamically unstable patients.

Urinary Trace Elements Are Biomarkers for Early Detection of Acute Kidney Injury.

Introduction: Acute kidney injury (AKI) is common in hospitalized patients and associated with poor outcomes. Current methods for identifying AKI (rise in serum creatinine [sCr] or fall in urine output [UO]) are inadequate and delay detection. Early detection of AKI with easily measurable biomarkers might improve outcomes by facilitating early implementation of AKI care pathways. Methods: From a porcine model of AKI, we identified trace elements (TEs) in urine that were associated with subsequent development of AKI. We tested these putative biomarkers in 2 observational cohort studies of patients at high risk of AKI: 151 patients undergoing cardiac surgery and 150 patients admitted to a general adult intensive care unit (ICU). Results: In adults admitted to the ICU, urinary cadmium (Cd) (adjusted for urinary creatinine) had area under the receiver operating characteristic curve (AUROC) 0.70 and negative predictive value (NPV) 89%; copper (Cu) had AUROC 0.76 and NPV 91%. In humans (but not pigs), urinary zinc (Zn) was also associated with AKI and, in the ICU study, had AUROC 0.67 and NPV 80%. In patients undergoing cardiac surgery, Zn had AUROC 0.77 and NPV 91%; urinary Cd and Cu had poor AUROC but NPV of 93% and 95%, respectively. In control studies, we found that the urinary biomarkers are stable at room temperature for at least 14 days and are not affected by other confounding factors, such as chronic kidney disease (CKD). Conclusion: Urinary Cd, Cu, and Zn are novel biomarkers for early detection of AKI. Urinary trace metals have advantages over proteins as AKI biomarkers because they are stable at room temperature and have potential for cheap point-of-care testing using electrochemistry.

Focus cardiac ultrasound core curriculum and core syllabus of the European Association of Cardiovascular Imaging.

There is a growing trend of using ultrasound examination of the heart as a first-line diagnostic tool for initial patient evaluation in acute settings. Focus cardiac ultrasound (FoCUS) is a standardized but restricted cardiac ultrasound examination that may be undertaken by a range of medical professionals with diverse backgrounds. The intention of this core curriculum and syllabus is to define a unifying framework for educational and training processes/programmes that should result in competence in FoCUS for various medical professionals dealing with diagnostics and treatment of cardiovascular emergencies. The European Association of Cardiovascular Imaging prepared this document in close cooperation with representatives of the European Society of Anaesthesiology, the European Association of Cardiothoracic Anaesthesiology, the Acute Cardiovascular Care Association of the European Society of Cardiology and the World Interactive Network Focused On Critical Ultrasound. It aims to provide the key principles and represents a guide for teaching and training of FoCUS. We offer this document to the emergency and critical care community as a reference outline for teaching materials and courses related to FoCUS, for promoting teamwork and encouraging the development of the field.

Can lean body mass be used to reduce the dose of heparin and protamine for obese patients undergoing cardiopulmonary bypass?

Increasing numbers of obese patients are presenting for cardiac surgery. The convention for heparin dose dictates that a bolus of 300 IU heparin per kilogram of total body weight (TBW) is administered before CPB. During CPB, the activated clotting time (ACT) is maintained for longer than 480 seconds. At the end of the procedure, protamine is administered to neutralize heparin and achieve hemostasis. Both of these drugs can have serious side effects: heparin can induce thrombocytopenia, and protamine has been known to cause reactions in patients allergic to fish, vasectomized men, and some patients with insulin-dependent diabetes. The calculation of lean body mass (LBM) may be a more accurate method of determining drug doses as opposed to TBW and may avoid giving obese patients a relative overdose of heparin, which must subsequently be neutralized with protamine. LBM can be determined by different methods. This study used bio-electrical impedance analysis as a simple, quick, and accurate method of calculating LBM. A comparison was made between two groups of patients whose body mass index (BMI) was >27 kg/m2: Group 1, n = 13, mean BMI = 32, mean body fat = 36% received the conventional dose of 300 IU/kg heparin for their TBW. Group 2, n = 14, mean BMI = 31, mean body fat = 35% received a dose of 300 IU/kg heparin for their calculated LBM. ACT was conducted before and after heparin administration. Additional heparin was administered as required to achieve target ACT > 400 s. Mean ACT results and total heparin doses were analyzed using unpaired two tailed t tests. Our results indicate that with care, a reduction of as much as 25% in the doses of heparin (p = 0.0001) and protamine can be achieved for a substantial number of patients classified as overweight or obese.

Advanced care nurse practitioners can safely provide sole resident cover for level three patients: impact on outcomes, cost and work patterns in a cardiac surgery programme.

OBJECTIVES: There are significant pressures on resident medical rotas on intensive care. We have evaluated the safety and feasibility of nurse practitioners (NPs) delivering first-line care on an intensive care unit with all doctors becoming non-resident. Previously, resident doctors on a 1:8 full-shift rota supported by NPs delivered first-line care to patients after cardiac surgery. Subsequently, junior doctors changed to a 1:5 non-resident rota and NPs onto a 1:7 full-shift rota provided first-line care. METHODS: A single centre before-and-after service evaluation on cardiac intensive care. KEY MEASURES FOR IMPROVEMENT: mortality rates, surgical trainee attendance in theatre and cost before and after the change. After-hour calls by NPs to doctors and subsequent actions were also audited after the change. RESULTS: The overall mortality rates in the 12 months before the change were 2.8 and 2.2% in the 12 months after (P = 0.43). The median [range] logistic EuroSCORE was 5.3 [0.9-84] before and 5.0 [0.9-85] after the change (P = 0.16). After accounting for the risk profile, the odds ratio for death after the change relative to before was 0.83, 95% confidence interval 0.41-1.69. Before the change, a surgical trainee attended theatre 467 of 702 (68%) cases. This increased to 539 of 677 (80%) cases after the change (P < 0.001). The annual cost of staffing the junior doctor and NP programme before the change was £933 344 and £764 691 after. In the year after the change, 192 after-hour calls were made to doctors. In 57% of cases telephone advice sufficed and doctors attended in 43%. CONCLUSIONS: With adequate training and appropriate support, resident NPs can provide a safe, sustainable alternative to traditional staffing models of cardiac intensive care. Training opportunities for junior surgeons increased and costs were reduced.

Unusual case of two synchronous intracavitary primary cardiac tumors.

We report a patient who had two histologic and distinct synchronous intracardiac tumors, with one located in each atrium. The second tumor was missed on intraoperative transesophageal echocardiography, but was discovered when the right atrium was opened using a bi-atrial trans-septal approach. We discuss the merits of this approach and the role of additional imaging for cardiac tumors.