A Pilot, Double-Blind, Randomized, Controlled Trial of High-Dose Intravenous Vitamin C for Vasoplegia After Cardiac Surgery.

OBJECTIVE: To conduct a pilot feasibility and physiologic efficacy study of high-dose vitamin C in patients with vasoplegia after cardiac surgery. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Two tertiary intensive care units (ICUs). PARTICIPANTS: Post-cardiac surgery patients with vasoplegia. INTERVENTIONS: The authors randomly assigned the patients to receive either high-dose intravenous vitamin C (1,500 mg every 6 hours) or placebo. The primary outcome was time from randomization to resolution of vasoplegia. Secondary outcomes included total norepinephrine equivalent dose in the first 2 days, ICU length of stay, ICU mortality, and in-hospital mortality. MEASUREMENTS AND MAIN RESULTS: The authors studied 50 patients (25 patients in each arms). The mean (standard deviation) time to resolution of vasoplegia was 27.0 (16.5) hours in the vitamin C group versus 34.7 (41.1) hours in the placebo group (mean decrease with vitamin C of 7.7 hours, 95% confidence interval -10.5 to 25.9, p = 0.40). The median (interquartile range) norepinephrine equivalent dose in the first 2 days was 64.9 (23.5-236.5) µg/kg versus 47.4 (21.4-265.9) µg/kg in the vitamin C and placebo group (p = 0.75). The median duration of ICU admission was similar (1.4 [0.5-2.5] days and 1.5 [0.5-3.3] days in the vitamin C and placebo group; p = 0.36). Only 1 patient, in the vitamin C arm, died. CONCLUSION: In patients with post-cardiac surgery vasoplegia, high-dose vitamin C infusion was feasible, appeared safe, and, within the limitations of a pilot study, did not achieve statistically faster resolution of vasoplegia.

An Investigation of Soundscape Factors Influencing Perceptions of Square Dancing in Urban Streets: A Case Study in a County Level City in China.

Square dancing is a popular music-related group physical exercise for health benefits in China mainly participated by mid-aged women and elderly people. This paper investigates the soundscape and enjoyment of the square dancing in urban streets through a case study in Lichuan, a county level city in southwest China, in December 2017. It examines the impact of gender, age, participation and places on perceptions of square dancing soundscape. Two sites along two main urban streets in the city were selected to conduct onsite investigations where residents spontaneously perform square dancing on a daily basis. Ethnographical observations were conducted to identify the social-physical features and sounds of both sites during the dance and without dance. Sound pressure measurements (LAeq and LAmax) were also conducted under the two conditions. An off-site survey was distributed through the local social media groups to understand residents' everyday experiences and perceptions of square dancing in the city; 106 responses were received for the off-site survey. T-tests and Chi-squared tests were used for statistical analysis of the survey data. The results show gender does appear to be a factor influencing the regularity of participation in square dancing, with a bias towards more female participants. Participation frequency of square dance has an impact on the enjoyment of square dancing. There is no correlation between the dislike of watching square dancing, or dislike of the music and a desire to restrict locations for square dancing.

The stop-flow arm equilibrium pressure in preoperative patients: Stressed volume and correlations with echocardiography.

BACKGROUND: The distending intravascular pressure at no flow conditions reflects the stressed volume. While this haemodynamic variable is recognised as clinically important, there is a paucity of reports of its range and responsiveness to volume expansion in patients without cardiovascular disease and no reports of correlations to echocardiographic assessments of left ventricular filling. METHODS: Twenty-seven awake (13 male), spontaneously breathing patients without any history of cardiopulmonary, vascular or renal disease were studied prior to induction of anaesthesia. The no-flow equilibrium pressure in the arm following rapid circulatory occlusion (Parm ) was measured via a radial arterial catheter. Transthoracic echocardiography was used to measure left ventricular end diastolic area and volume as well as the diameter of the inferior vena cava. The Parm and echocardiographic variables were measured before and after administration of 500 mL 0.9% NaCl over 10 minutes. Changes were analysed by paired t test, Pearson's correlation and multiple linear regression. RESULTS: Parm increased overall from 22 ± 5 mm Hg to 25 ± 6 mm Hg (mean difference 3.0 ± 4.5 mm Hg, P = 0.002) following the fluid bolus with corresponding increases in arterial pressure and echocardiographic variables. Variability in the direction of the Parm response reflected concomitant changes in vascular compliance. Only weak correlations were observed between changes in Parm and inferior vena cava diameter indexed to body surface area (R2  = 0.29, P = 0.01). CONCLUSION: Preoperative measurements of Parm increased following acute expansion of the intravascular volume. Echocardiography demonstrated poor correlation with Parm .

Levels of training in critical care echocardiography in adults. Recommendations from the College of Intensive Care Medicine Ultrasound Special Interest Group.

Critical care echocardiography (CCE) is commonly performed in many intensive care units across Australia and New Zealand (ANZ). The scope of practice ranges from Basic CCE through to Advanced CCE and includes the use of transthoracic echocardiography and transoesophageal echocardiography. Many training and qualification pathways exist with no standardisation of education goals. This document defines different levels of CCE expertise and recommends minimum training standards for each level of adult CCE in ANZ. Guidelines committee of College of Intensive Care Medicine's Ultrasound Special Interest Group held multiple face to face meetings, organised teleconferences, conducted a survey of the Fellows of the college and reviewed the international CCE training pathways prior to writing these guidelines.

Pearls and pitfalls in comprehensive critical care echocardiography.

Critical care echocardiography is developing rapidly with an increasing number of specialists now performing comprehensive studies using Doppler and other advanced techniques. However, this imaging can be challenging, interpretation is far from simple in the complex critically ill patient and mistakes can be easy to make. We aim to address clinically relevant areas where potential errors may occur and suggest methods to hopefully improve accuracy of imaging and interpretation.

Peripheral venoarterial extracorporeal membrane oxygenation for severe hyperlactataemia after cardiac surgery: a pilot study.

BACKGROUND: Severe hyperlactataemia in patients after cardiac surgery is associated with poor prognosis and implies possible splanchnic hypoperfusion. Peripheral venoarterial extracorporeal membrane oxygenation (splanchnic ECMO) may be more effective at reducing lactic acidosis for these patients. OBJECTIVE: To investigate whether splanchnic ECMO attenuates hyperlactataemia and liver enzyme release in these patients, despite them having a cardiac index > 2 L/min/m2 and a mixed venous oxygen saturation > 55%. DESIGN AND PARTICIPANTS: Retrospective matched case- control study of patients treated with splanchnic ECMO for hyperlactataemia. Seven patients who had had cardiac surgery were treated with splanchnic ECMO compared with seven matched control patients. RESULTS: We observed a mean decrease in lactate levels from 9.9 mmol/L (SD, 2.9 mmol/L) to 1.4 mmol/L (SD, 0.6 mmol/L) in patients receiving 48 hours of splanchnic ECMO, compared with a mean of 10.4 mmol/L (SD, 2.8 mmol/L) to 4.4 mmol/L (SD, 5 mmol/L) during 48 hours in control patients (P < 0.0001). Normalisation of lactate levels (to < 2 mmol/L) was achieved within a mean of 16.3 hours (SD, 14.6 hours) with splanchnic ECMO, compared with 38.3 hours (SD, 23.8 hours) in the control group (P = 0.029). The median increase in alanine aminotransferase level with splanchnic ECMO was 68% (range, -84% to 2015%) compared with 158% (range: 0%-6024%) (not significant) in control patients. CONCLUSION: In a selected cohort of patients who had had cardiac surgery with severe post-operative hyperlactataemia, despite an acceptable cardiac index and a mixed venous oxygen saturation, splanchnic ECMO appeared to reduce overall lactate levels and time to normalisation of lactataemia.

The haemodynamic effects of bolus versus slower infusion of intravenous crystalloid in healthy volunteers.

PURPOSE: This pilot study aimed to characterise the haemodynamic effect of 1L of IV normal saline (NS) administered as a rapid versus slow infusion on cardiac output (CO), heart rate (HR), systemic blood pressures, and carotid blood flow in six healthy volunteers. MATERIALS AND METHODS: Six healthy male volunteers aged 18-65years were randomized to receive 1L NS given over 30min or 120min. On a subsequent study session the alternate fluid regimen was administered. Haemodynamic data was gathered using a non-invasive finger arterial pressure monitor (Nexfin®), echocardiography and carotid duplex sonography. Time to micturition and urine volume was also assessed. RESULTS: Compared to baseline, rapid infusion of 1L of saline over 30min produced a fall in Nexfin®-measured CO by 0.62L/min (p<0.001), whereas there was a marginal but significant increase during infusion of 1L NS over 120min of 0.02L/min (p<0.001). This effect was mirrored by changes in HR and blood pressure (BP) (p<0.001). There were no significant changes in carotid blood flow, time to micturition, or urine volume produced. CONCLUSIONS: Slower infusion of 1L NS in healthy male volunteers produced a greater increase in CO, HR and BP than rapid infusion.

Minimum standards for ultrasound equipment in intensive care. Recommendations from CICM Ultrasound Special Interest Group.

Critical care ultrasonography allows rapid bedside assessment and monitoring of severely ill patients. It provides important information on a real-time basis for patients' management and clinical decision-making, leading to improvements in delivered quality of care. Provision of this service is not possible without appropriate equipment. This document recommends minimum standards for ultrasound equipment required for use in intensive care units in Australia and New Zealand.

Inconsistencies in authoritative national paediatric workforce data sources.

Objective National health workforce data are used in workforce projections, policy and planning. If data to measure the current effective clinical medical workforce are not consistent, accurate and reliable, policy options pursued may not be aligned with Australia's actual needs. The aim of the present study was to identify any inconsistencies and contradictions in the numerical count of paediatric specialists in Australia, and discuss issues related to the accuracy of collection and analysis of medical workforce data. Methods This study compared respected national data sources regarding the number of medical practitioners in eight fields of paediatric speciality medical (non-surgical) practice. It also counted the number of doctors listed on the websites of speciality paediatric hospitals and clinics as practicing in these eight fields. Results Counts of medical practitioners varied markedly for all specialties across the data sources examined. In some fields examined, the range of variability across data sources exceeded 450%. Conclusions The national datasets currently available from federal and speciality sources do not provide consistent or reliable counts of the number of medical practitioners. The lack of an adequate baseline for the workforce prevents accurate predictions of future needs to provide the best possible care of children in Australia. What is known about the topic? Various national data sources contain counts of the number of medical practitioners in Australia. These data are used in health workforce projections, policy and planning. What does this paper add? The present study found that the current data sources do not provide consistent or reliable counts of the number of practitioners in eight selected fields of paediatric speciality practice. There are several potential issues in the way workforce data are collected or analysed that cause the variation between sources to occur. What are the implications for practitioners? Without accurate data on which to base decision making, policy options may not be aligned with the actual needs of children with various medical needs, in various geographic areas or the nation as a whole.

Direct cerebral perfusion and cooling in experimental cardiac arrest.

BACKGROUND: Cerebral protection is a key priority during cardiac arrest (CA). However, current approaches are suboptimal. OBJECTIVE: To test whether direct perfusion and cooling of the anterior cerebral circulation by means of cerebral vessel cannulation and extracorporeal membrane oxygenation (ECMO) increases cerebral oxygenation and induces cerebral hypothermia during CA. METHODS: We performed proof-of-concept animal experiments in sheep. We cannulated the carotid artery (for antegrade perfusion) or the jugular vein (for retrograde perfusion) for direct perfusion and cooling, and the jugular vein on the opposite side for drainage. We connected these cannulae to an ECMO circuit. We induced CA and, after 10 minutes, and during open-chest cardiac massage, we provided ECMO-based perfusion and cooling. We measured cerebral tissue oxygen saturation (SctO2) by near infrared spectroscopy (NIRS) and cerebral temperature by means of invasively inserted tissue temperature probes. RESULTS: In the antegrade perfusion experiments (n = 2), CA markedly decreased the SctO2 to below 40% over 10 minutes, despite open-chest cardiac massage. ECMO-based cerebral perfusion and cooling increased SctO2 levels to 60% and lowered cerebral temperature to 25°C within about 3 minutes. With retrograde perfusion (n = 2), ECMObased cerebral perfusion and cooling was less effective; ECMO increased SctO2 levels slowly and to a much lesser extent and similarly decreased cerebral temperature slowly and to a lesser extent. CONCLUSIONS: During experimental CA, cerebral perfusion and cooling are possible by means of an ECMO circuit connected to the anterior cerebral circulation. Antegrade perfusion appears to be superior. Further investigations of the antegrade perfusion technique appear justified.

The native cardiac output in human sepsis: a systematic review.

BACKGROUND: The cardiac output (CO) response to sepsis is typically measured in the intensive care unit after modification by fluid and/or vasoactive drug resuscitation and found to be hyperdynamic. In contrast, the native (preresuscitation) CO in human sepsis is poorly defined. DESIGN AND DATA SOURCES: Systematic literature review of studies reporting the cardiac index (CI) of patients with sepsis before resuscitation, using searches of PubMed, MEDLINE and Embase. RESULTS: We identified 5667 citations from 1929 to 2014. Of 179 articles meeting inclusion criteria, only four studies reported CO measurements before any treatment, in a total of 181 patients. Only two of the four studies reported age distribution (mean age, 72 years) for a total of 159 patients. We calculated the mean CI in these four studies to be 2.68 L/ min/m(2) (SD, 0.42 L/min/m(2); median, 2.52 L/min/m(2); range, 2.36-3.3 L/min/m(2)). Only one study presented mixed venous oxygen saturation data as an estimate of the adequacy of perfusion, and in three studies there was evidence of reduced cardiac performance. CONCLUSION: Data about the native CO in human sepsis are scant because therapeutic intervention usually precedes measurement. From the limited data available, it appears that most patients are in a normodynamic haemodynamic state at presentation, and cardiac performance also seems to be impaired at the earliest stage of sepsis. As initial resuscitation is partly predicated on assumptions about the underlying cardiovascular physiology, our findings suggest the need to address this knowledge deficit in the management of patients with severe sepsis.

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.

Informed consent in the intensive care unit: the experiences and expectations of patients and their families.

OBJECTIVE: To describe the awareness of intensive care unit patients and their next of kin (NoK) about invasive procedures and their expectations of informed consent for procedures in the ICU. DESIGN AND SETTING: A written survey of patients and their NoK in a tertiary, university-affiliated ICU, using multiplechoice questions, Likert scales and comments to generate semiquantitative and qualitative data. PARTICIPANTS: Fifty-one ICU patients and 69 NoK completed the survey. Inclusion criteria were unplanned ICU admission, ICU length-of-stay > 24 hours, English speaking and competent to consent to participate. MAIN OUTCOME MEASURES: Proportion of procedures respondents were aware had occurred during ICU admission; satisfaction with information received; preferred method of receiving information and giving consent; and expectations of when procedural consent is required. RESULTS: Patients and NoK were unaware of many procedures performed during their admission. Respondents correctly identified 49% (95% CI, 45%-53%) of procedures performed during the patient's ICU admission. Despite this, most patients (80%; 95% CI, 69%-91%) and NoK (94%; 95% CI, 89%-100%) were satisfied with information provided about procedures. Over half of respondents (55%; 95% CI, 46%-64%) only expected consent for procedures that were "risky or not routine". About one-quarter (27%; 95% CI, 23%-31%) expected to give consent before every procedure and 15% (95% CI, 11%-18%) expected no procedural consent process. Patients and NoK strongly preferred a verbal rather than written consent process. CONCLUSIONS: Our results suggest there is a limited degree of support for routine procedural consent from ICU patients and their NoK.

Informed consent for procedures in the intensive care unit: ethical and practical considerations.

There is increasing interest in procedural consent (informed consent for invasive procedures) in the intensive care unit. We reviewed studies of procedural consent and show that it is not yet routine practice to obtain consent before performing invasive procedures on ICU patients. We considered logistical barriers to procedural consent in the critical care environment and the ethical implications of introducing routine procedural consent to the ICU.

A novel echocardiographic imaging technique, intracatheter echocardiography, to guide veno-venous extracorporeal membrane oxygenation cannulae placement in a validated ovine model.

BACKGROUND: Echocardiography plays a fundamental role in cannulae insertion and positioning for extracorporeal membrane oxygenation (ECMO). Optimal access and return cannulae orientation is required to prevent recirculation. The aim of this study was to compare a novel imaging technique, intracatheter echocardiography (iCATHe), with conventional intracardiac echocardiography (ICE) to guide placement of ECMO access and return venous cannulae. METHODS: Twenty sheep were commenced on veno-venous ECMO (VV ECMO). Access and return ECMO cannulae were positioned using an ICE-guided technique. Following the assessment of cannulae position, the ICE probe was then introduced inside the cannulae, noting location of the tip. After 24 h, the sheep were euthanized and cannulae position was determined at post mortem. The two-tailed McNemar test was used to compare iCATHe with ICE cannulae positioning. RESULTS: ICE and iCATHe imaging was possible in all 20 sheep commenced on ECMO. There was no significant difference between the two methods in assessing access cannula position (proportion correct for each 90%, incorrect 10%). However, there was a significant difference between ICE and iCATHe success rates for the return cannula (p = 0.001). Proportion correct for iCATHe and ICE was 80% and 15% respectively. iCATHe was 65% more successful (95% CI 27% to 75%) at predicting the placement of the return cannula. There were no complications related to the ICE or iCATHe imaging. CONCLUSION: iCATHe is a safe and feasible imaging technique to guide real-time VV ECMO cannulae placement and improves accuracy of return cannula positioning compared to ICE.