Prehospital point-of-care ultrasound in ruptured abdominal aortic aneurysms-a retrospective cohort study.

BACKGROUND: Patients with ruptured abdominal aortic aneurysm (rAAA) require immediate vascular treatment to survive. The use of prehospital point-of-care ultrasound (POCUS) may support clinical assessment, correct diagnosis, appropriate triage and reduce system delay. The aim was to study the process of care and outcome in patients receiving prehospital POCUS versus patients not receiving prehospital POCUS in patients with rAAA, ruptured iliac aneurysm or impending aortic rupture. METHODS: We performed a retrospective cohort study in patients diagnosed with rAAA in the Central Denmark Region treated by a prehospital critical care physician from 1 January 2017 to 31 December 2021. Performance of prehospital POCUS was extracted from the prehospital electronic health records. System delay was defined as the time from the emergency phone call to the emergency medical service dispatch centre until the start of surgery. Data on patients primary hospital admission to a centre with/without vascular treatment expertise, treatments and complications including death were extracted from electronic health records. RESULTS: We included 169 patients; prehospital POCUS was performed in 124 patients (73%). Emergency surgical treatment was performed in 71 patients. The overall survival in the POCUS group was 39% versus 16% in the NO POCUS group (hazard ratio (HR) (95% 0.60, 95% CI: 0.41-0.89, p = .011). In the POCUS group 99/124 (80%) were directly admitted to a vascular surgical centre versus 25/45 (56%) in the NO POCUS, RD 24% (95% CI: 8-40)), (p = .002). In the POCUS group, system delay was a median of 142 minutes (interquartile range (IQR) 121-189) and a median of 232 minutes (IQR 166-305) in the NO POCUS group (p = .006). In a multivariable analysis incorporating age, sex, previously known rAAA, and typical clinical symptoms of rAAA, the HR for death was 0.57, 95% CI 0.38-0.86 (p = .008) favouring prehospital POCUS. CONCLUSIONS: Prehospital POCUS was associated with reduced time to treatment, higher chance of operability and significantly higher 30-day survival in patients with rAAA, ruptured iliac aneurysm or impending rupture of an AAA in this retrospective study. Residual confounding cannot be excluded. This study supports the clinical relevance of prehospital POCUS of the abdominal aorta.

Validity and reliability of measurement of peripheral oxygen saturation during the 6-Minute Walk Test in patients with systemic sclerosis.

Peripheral oxygen saturation (SpO2) using the fingers may have important limitations due to Raynaud's phenomenon and sclerodactyly in patients with systemic sclerosis (SSc). Sensors located at more central body positions may be more accurate as these as less prone to Raynaud attacks. To determine the validity and reliability of the SpO2 measured at the finger, forehead, and earlobe during the 6-Minute Walk Test (6MWT). Eighty two patients with SSc had an arterial line placed while performing the 6MWT. Peripheral oxygen saturation was simultaneously measured by finger, forehead, and earlobe sensors and compared to the arterial oxygen saturation (SaO2) measured before and after the 6MWT. 40 patients repeated the 6MWT one week later to determine re-test reliability. We used Bland-Altman plots to display the agreement between SpO2 and SaO2. The intraclass correlation coefficient for repeated measurement of minimum SpO2 was calculated. The mean difference between SpO2 and SaO2 after the 6MWT was - 3% (SD: ± 5), 0% (SD: ± 2), and 1% (SD: ± 2) for the finger, forehead, and earlobe, respectively. The minimum SpO2 measured at the finger demonstrated the poorest re-test reliability: The ICC (95% CI) showed good agreement using the ear and forehead probe (ICCear = 0.89 [95% CI 0.80; 0.94]; ICCforehead = 0.77 [95% CI 0.60; 0.87]), while a modest reliability was found using the finger probe (ICCfinger = 0.65 95% CI [0.43; 0.80]). SpO2 should be measured using either the earlobe or forehead during the 6MWT in patients with SSc. Clinical Trials.Gov (NCT04650659).

The effects of respiratory rate and tidal volume on pulse pressure variation in healthy lungs-a generalized additive model approach may help overcome limitations.

Pulse pressure variation (PPV) is a well-established method for predicting fluid responsiveness in mechanically ventilated patients. The predictive accuracy is, however, disputed for ventilation with low tidal volume (VT) or low heart-rate-to-respiratory-rate ratio (HR/RR). We investigated the effects of VT and RR on PPV and on PPV's ability to predict fluid responsiveness. We included patients scheduled for open abdominal surgery. Prior to a 250 ml fluid bolus, we ventilated patients with combinations of VT from 4 to 10 ml kg-1 and RR from 10 to 31 min-1. For each of 10 RR-VT combinations, PPV was derived using both a classic approach and a generalized additive model (GAM) approach. The stroke volume (SV) response to fluid was evaluated using uncalibrated pulse contour analysis. An SV increase > 10% defined fluid responsiveness. Fifty of 52 included patients received a fluid bolus. Ten were fluid responders. For all ventilator settings, fluid responsiveness prediction with PPV was inconclusive with point estimates for the area under the receiver operating characteristics curve between 0.62 and 0.82. Both PPV measures were nearly proportional to VT. Higher RR was associated with lower PPV. Classically derived PPV was affected more by RR than GAM-derived PPV. Correcting PPV for VT could improve PPV's predictive utility. Low HR/RR has limited effect on GAM-derived PPV, indicating that the low HR/RR limitation is related to how PPV is calculated. We did not demonstrate any benefit of GAM-derived PPV in predicting fluid responsiveness.Trial registration: ClinicalTrials.gov, reg. March 6, 2020, NCT04298931.

Diaphragmatic dysfunction is associated with postoperative pulmonary complications and phrenic nerve paresis in patients undergoing thoracic surgery.

PURPOSE: We aimed to quantify perioperative changes in diaphragmatic function and phrenic nerve conduction in patients undergoing routine thoracic surgery. METHODS: A prospective observational study was performed in patients undergoing esophageal resection or pulmonary lobectomy. Examinations were carried out the day prior to surgery, 3 days and 10-14 days after surgery. Endpoints for diaphragmatic function included ultrasonographic measurements of diaphragmatic excursion and thickening fraction. Endpoints for phrenic nerve conduction included baseline-to-peak amplitude, peak-to-peak amplitude, and transmission delay. Measurements were assessed on both the surgical side and the non-surgical side of the thorax. RESULTS: Forty patients were included in the study. Significant reductions in diaphragmatic excursion were seen on the surgical side of the thorax for all excursion measures (posterior part of the right hemidiaphragm, p < 0.001; hemidiaphragmatic top point, p < 0.001; change in intrathoracic area, p < 0.001). Significant changes were seen for all phrenic nerve measures (baseline-to-peak amplitude, p < 0.001; peak-to-peak amplitude, p < 0.001; transmission delay, p = 0.041) on the surgical side. However, significant changes were also seen on the non-surgical side for all phrenic nerve measures (baseline-to-peak amplitude, p < 0.001; peak-to-peak amplitude, p < 0.001; transmission delay, p = 0.022). A postoperative reduction in posterior diaphragmatic excursion of more than 50% was significantly associated with postoperative pulmonary complications (coefficient: 2.69 (95% CI [1.38, 4.01], p < 0.001). CONCLUSION: Thoracic surgery caused a significant unilateral reduction in diaphragmatic excursion on the surgical side of the thorax, which was accompanied by significant changes in phrenic nerve conduction. However, phrenic nerve conduction was also significantly affected on the non-surgical side to a lesser extent, which was not mirrored in diaphragmatic excursion. Our findings suggest that phrenic nerve paresis plays a role in postoperative diaphragmatic dysfunction, which may be a contributing factor in the pathogenesis of postoperative pulmonary complications. CLINICAL TRIALS REGISTRATION NUMBER: NCT04507594.

The haemodynamic effects of phenylephrine after cardiac surgery.

BACKGROUND: Phenylephrine increases systemic- and pulmonary resistances and therefore may increase blood pressures at the expense of blood flow. Cardio-pulmonary bypass alters vasoreactivity and many patients exhibit chronotropic insufficiency after cardiac surgery. We aimed to describe the haemodynamic effects of phenylephrine infusion after cardiac surgery. METHODS: Patients in steady state after low-risk cardiac surgery received incremental infusion rates of phenylephrine up to 1.0 µg/kg/min with the aim of increasing systemic mean arterial blood pressure 20 mmHg. Invasive haemodynamic parameters, including pulmonary wedge pressures, were captured along with echocardiographic measures of biventricular function before, during phenylephrine infusion at target systemic blood pressure, and 20 min after phenylephrine discontinuation. RESULTS: Thirty patients were included. Phenylephrine increased mean arterial pressure increased from 78 (±9) mmHg to 98 (±10) mmHg with phenylephrine infusion. Also, pulmonary blood pressure as well as systemic- and pulmonary resistances increased. The ratio between systemic- and pulmonary artery resistances did not change statistically significantly (p = .59). Median cardiac output was 4.35 (interquartile range [IQR] 3.6-5.4) L/min at baseline and increased significantly with phenylephrine infusion (median Δcardiac output was 0.25 [IQR 0.1-0.6] L/min) (p = .012). Pulmonary artery wedge pressure increased from 10.2 (±3.0) mmHg to 11.9 (±3.4) mmHg (p < .001). This was accompanied by significant increases in central venous pressure. Phenylephrine infusion increased left ventricular end-diastolic volume from 105 (±46) mL to 119 (±44) mL (p < .001). All results of phenylephrine infusion were reversed with discontinuation. CONCLUSION: In haemodynamically stable patients after cardiac surgery, phenylephrine increased PVR and SVR, but did not change the PVR/SVR ratio. Phenylephrine increased biventricular filling pressures and left ventricular end-diastolic area. Consequently, CO increased as ejection fraction was maintained. These findings do not discourage the use of phenylephrine after low-risk cardiac surgery. REGISTRATION: clinicaltrial.gov (identifier NCT04419662).

Collaboration for Evidence-based Practice and Research in Anaesthesia (CEPRA): A consortium initiative for perioperative research.

Evidence in perioperative care is insufficient. There is an urgent need for large perioperative research programmes, including pragmatic randomised trials, testing daily clinical treatments and unanswered question, thereby providing solid evidence for effects of interventions given to a large and growing number of patients undergoing surgery and anaesthesia. This may be achieved through large collaborations. Collaboration for Evidence-based Practice and Research in Anaesthesia (CEPRA) is a novel collaborative research network founded to pursue evidence-based answers to major clinical questions in perioperative medicine. The aims of CEPRA are to (1) improve clinical treatment and outcomes and optimise the use of resources for patients undergoing anaesthesia and perioperative care, and (2) disseminate results and inform caretakers, patients and relatives, and policymakers of evidence-based treatments in anaesthesia and perioperative medicine. CEPRA is inclusive in its concept. We aim to extend our collaboration with all relevant clinical collaborators and patient associations and representatives. Although initiated in Denmark, CEPRA seeks to develop an international network infrastructure, for example, with other Nordic countries. The work of CEPRA will follow the highest methodological standards. The organisation aims to structure and optimise any element of the research collaboration to reduce economic costs and harness benefits from well-functioning research infrastructure. This includes successive continuation of trials, harmonisation of outcomes, and alignment of data management systems. This paper presents the initiation and visions of the CEPRA network. CEPRA aims to be inclusive, patient-focused, methodologically sound, and to optimise all aspects of research logistics. This will translate into faster research conduct, reliable results, and accelerated clinical implementation of results, thereby benefiting millions of patients whilst being cost and labour-saving.

A comprehensive echocardiographic analysis during simulated hypovolaemia: An observational study.

BACKGROUND: Peri-operative and critically ill patients often experience mild to moderate hypovolaemic shock with preserved mean arterial pressure (MAP), heart rate (HR) and decreased stroke volume index (SVI). OBJECTIVES: The aim of this study was to evaluate echocardiographic parameters during simulated mild to moderate central hypovolaemia. DESIGN: This was a prospective preclinical study. SETTING: Laboratory trial performed in Charité-Universitätsmedizin Berlin, Germany. PATIENTS AND METHODS: Thirty healthy male volunteers underwent graded central hypovolaemia using a lower body negative pressure (LBNP) chamber with a stepwise decrease to simulate a mild (-15 mmHg), mild-to-moderate (-30 mmHg), and moderate state of hypovolaemic shock (-45 mmHg). During every stage, a transthoracic echocardiography examination (TTE) was performed by a certified examiner. MAIN OUTCOME MEASURES: Systolic and diastolic myocardial performance markers, as well as cardiac volumes were recorded during simulated hypovolaemia and compared to baseline values. RESULTS: During simulated hypovolaemia via LBNP, SVI decreased progressively at all stages, whereas MAP and HR did not consistently change. Left ventricular (LV) ejection fraction decreased at -30 and -45 mmHg. Simultaneously with SVI decline, LV global longitudinal strain (LV GLS), tricuspid annular plain systolic excursion (TAPSE), and right ventricular RV S' and left-atrial end-systolic volume (LA ESV) decreased compared to baseline at all stages. CONCLUSIONS: In this study, simulated central hypovolaemia using LBNP did not induce consistent changes in MAP and HR. SVI decreased and was associated with deteriorated right- and left-ventricular function, observed with echocardiography. The decreased filling status was characterised by decreased LA ESV. CLINICAL TRIAL NUMBER: ClinicalTrials.gov Identifier: NCT03481855.

The effects of preoperative focused cardiac ultrasound in high-risk patients: A randomised controlled trial (PREOPFOCUS).

BACKGROUND: Surgery is the third most common cause of mortality worldwide. Focused cardiac ultrasound (FOCUS) yields information on cardiac status and discloses the presence of unknown pathology. Preoperative FOCUS changes patient treatment, allowing for a patient-tailored anaesthesia. We hypothesised that preoperative FOCUS would reduce the proportion of patients who were either admitted to hospital for more than 10 days or who were dead within 30 days after high-risk, non-cardiac surgery. METHODS: This was a randomised, controlled, multi-center study. Patients ≥65 years of age, admitted for urgent orthopaedic- or abdominal surgery, scheduled for general- or neuraxial anaesthesia and with ASA 3/4 were eligible for inclusion. Patients were randomised in a 1:1 ratio to preoperative FOCUS or no preoperative FOCUS performed in accordance with a predefined protocol. Primary endpoint was the proportion of patients admitted more than 10 days or who were dead within 30 days. Secondary endpoints included major complications, days of admission and changes in anaesthesia handling. RESULTS: During the second COVID-19 wave the study monitoring committee terminated the study prematurely. We included 338 patients of which 327 were included in the final analysis. In the FOCUS group, 41/163 (25%) patients met the criteria for the primary endpoint versus 35/164 (21%) for the control group, adjusted odds ratio 1.37 (95% CI 0.86-2.30), p = .36. The proportions of patients who developed major complications did not differ significantly between groups. Length of hospital stay was 4 (3-8) days in the FOCUS group and 4 (3-7) days on the control group (adjusted p = .24). CONCLUSION: The routine availability of preoperative FOCUS assessment in this cohort does not appear to reduce the risk for hospitalisation exceeding 10 days or 30-day mortality, although study enrolment was prematurely terminated.

Ultrasound Hepatic Vein Ratios Are Associated With the Development of Acute Kidney Injury After Cardiac Surgery.

OBJECTIVE: The authors investigated the use of hepatic venous and right-heart ultrasound parameters in predicting cardiac surgery-associated acute kidney injury (AKI). DESIGN: This was a prospective, contextual, descriptive two-center study. Blood tests,clinical and ultrasound data were obtained preoperatively, and postoperative day one, and day four. The hepatic vein, inferior vena cava, and right-heart Doppler ultrasound parameters were obtained and analyzed. SETTING: The sites of the study were Johannesburg, South Africa, and Aarhus, Denmark. PARTICIPANTS: Adult patients who satisfied inclusion criteria, between August 2019 and January 2020, were included, with a total of 152 participants. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The median (interquartile range) age of patients was 68 (55-73) years, predominantly male, and the majority were hypertensive. Of 152 patients analyzed, 54 (35%) patients developed AKI. Among these, 37 (69%) were classified as Kidney Disease: Improving Global Outcomes (KDIGO) stage I, 11 (20%) as stage II, while six (11%) were stage III. Age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.00-1.10 p = 0.031), The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (AOR 1.43, 95% CI 1.14-1.80, p = 0.005], and preoperative serum creatinine (AOR 1.04, 95% CI 1.01-1.08, p = 0.013) were predictive of AKI. Those who developed AKI had experienced longer cardiopulmonary bypass (CPB) times (p < 0.001). Preoperatively, hepatic vein S-wave measurements were significantly higher in patients with AKI (p < 0.05). On postoperative day one (D1), the hepatic vein flow ratios of patients with AKI were significantly decreased, driven by low S waves and high D waves, and accompanied by significantly elevated central venous pressure (CVP) levels. CVP levels on D1 postoperatively were predictive of AKI (AOR 1.31, 95% CI 1.11-1.55, p = 0.001). Measurements of right ventricular (RV) base, tricuspid annular plane excursion (TAPSE), and inferior vena cava were not associated with the development of AKI (p > 0.05). CONCLUSION: There was an association between the development of AKI and a decrease in hepatic flow ratios on D1, driven by low S-wave and high D-wave velocities. The presence of venous congestion was reflected by significantly elevated CVP values, which were independently associated with AKI on D1. RV base and TAPSE measurements were, however, not associated with AKI. These parameters may reflect perioperative circumstances, including prolonged CPB times and potential fluid management, which can be modified in this period.

Effects of changes in position, positive end-expiratory pressure and mean arterial pressure on renal, portal and hepatic Doppler ultrasound perfusion indices: a randomized crossover study in cardiac surgery patients.

Point-of-care ultrasound perfusion indices can be used for detection of AKI and venous congestion. Patients in the postoperative- and intensive care units are frequently exposed to alternating treatment and loading conditions. We aimed to study the effects of changes in preload (patient positioning), positive end-expiratory pressure (PEEP) and afterload (phenylephrine) on renal, portal and hepatic ultrasound indices. We hypothesized that renal resistive index was not influenced by changes in PEEP and patient positioning. This was a single-site, randomized, crossover study. Patients above 18 years scheduled for elective open-heart surgery at Aarhus University Hospital, Denmark, were available for inclusion. Patients were randomized to a sequence of six combinations of PEEP and position in addition to an increase in mean arterial pressure by phenylephrine. Thirty-one patients participated in the study. Resistive index was influenced by positional change (P = 0.007), but not by change in PEEP (P = 0.50) (Table 1). Renal venous stasis index and portal pulsatility fraction increased in the raised legs position (P ≤ 0.019), but not with increases in PEEP. Renal venous flow pattern and hepatic venous flow pattern were affected by position (P ≤ 0.019), but not by PEEP. None of the ultrasound indices were significantly changed by infusion of phenylephrine. Doppler perfusion indices were significantly affected by changes in preload, but not by changes in PEEP or afterload. Although the changes in the Doppler ultrasound indices were significant, they were small in absolute numbers. Therefore, from a clinical perspective, the ultrasound indices were robust.Trial registration Registered at clinicaltrials.com, first posted online June 5th 2020, identifier: NCT04419662.

Supraclavicular ultrasonographic real-time guidance of peripherally inserted central catheters - A feasibility study.

BACKGROUND: Mispositioning is common during insertion of peripherally inserted central catheters. Ultrasonographic visualization of anatomical structures may enable continuous guidance during insertion. The aim was to investigate the feasibility of ultrasonographic real-time guidance of peripherally inserted central catheter placement using the supraclavicular fossa view. METHODS: An observational quality control study was performed including 20 patients. Ultrasonography was performed via the right supraclavicular fossa using a microconvex probe identifying the junction between the right internal jugular- and the subclavian vein forming the right brachiocephalic vein. The wire guide tip was identified at the junction allowing estimation of catheter length. The catheter stiffening wire was followed in real-time into the right brachiocephalic vein towards the superior vena cava. Mispositions and the ability to redirect in real-time were detected. Final catheter tip positions were evaluated by either fluoroscopy or a chest radiograph. RESULTS: Catheters were successfully placed in 19/20 patients. In all patients the junction and the right brachiocephalic vein was identified. Two thrombi were identified in the right brachiocephalic vein and left-sided insertions were performed. In 16 of 17 right-sided insertions, wire guide and catheter stiffening wire were visible. Of the 16 visual catheters, 15 could be followed into the right brachiocephalic vein. Real-time mispositioning was identified in eight cases and optimal redirection was successful in seven. All ultrasound-guided catheter length estimations were adequate. CONCLUSIONS: Supraclavicular ultrasonographic real-time guidance for peripherally inserted central catheter placement was feasible and enabled successful placement together with detection and redirection of mispositioned catheters without delay.

The impact of minimal invasive extracorporeal circulation on postoperative kidney function.

INTRODUCTION: Acute kidney injury following cardiac surgery is a frequent complication associated with increased mortality and morbidity. Minimal invasive extracorporeal circulation is suggested to preserve postoperative renal function. The aim of this study was to assess the impact of minimal invasive versus conventional extracorporeal circulation on early postoperative kidney function. METHODS: Randomized controlled trail including 60 patients undergoing elective stand-alone coronary artery bypass graft surgery and allocated in a 1:1 ratio to either minimal invasive (n = 30) or conventional extracorporeal circulation (n = 30). Postoperative kidney injury was assessed by elevation of plasma neutrophil gelatinase-associated lipocalin (NGAL), a sensitive tubular injury biomarker. In addition, we assessed changes in estimated glomerular filtration rate (eGFR), and the incidence of acute kidney injury according to the Acute Kidney Injury Network (AKIN) classification. RESULTS: We observed no differences between groups regarding increase of plasma NGAL (p = 0.31) or decline of eGFR (p = 0.82). In both groups, 6/30 patients developed acute kidney injury according to the AKIN classification, all regaining preoperative renal function within 30 days. CONCLUSION: Our findings challenge the superiority of minimal invasive compared to conventional extracorporeal circulation in terms of preservation of renal function following low-risk coronary surgery.

The clinical performance of midline catheters-An observational study.

BACKGROUND: The use of peripheral venous catheters (PVCs) is hampered by short dwell time, and central venous catheters (CVCs) are often preferred for medium- to long-time intravenous treatment. Ultrasound techniques allow for easy catheter insertion into the major veins of the upper arm. A new generation of midline catheters, PowerGlide Pro, utilises a one-hand Seldinger technique and can be inserted by one single operator without assistance. This study aimed to evaluate the clinical performance of the PowerGlide Pro midline catheter. METHODS: Consecutively inserted midline catheters were followed in a prospective, observational quality control study. Endpoints were dwell time, the incidence of premature catheter removal, causes of catheter removal and the dwell time and incidence rates of predefined subgroups representing potential effect modifiers. RESULTS: Hundred midline catheters, of which 98 were accessible to follow-up, were inserted in 70 patients. Median dwell time was 8 days and 60 catheters were removed before the indication for intravenous therapy had ceased. The overall incidence for premature catheter removal was 71.8/1000 days and no significant effects of subgroups (sex, body mass index, catheter reinsertions, significant comorbidity, anticoagulant therapy, irritant infusions) were identified for either dwell time or the incidence rate for premature midline catheter removal. The most frequent reasons for premature catheter removal were pain during infusion, clotted catheter or signs of infection. CONCLUSION: The median dwell time of the midline catheters was 8 days with substantial variation, whereas the incidence for premature catheter removal was 71.8/1000 catheter days. The majority of midline catheters were removed prematurely.

Automated echocardiography for measuring and tracking cardiac output after cardiac surgery: a validation study.

Echocardiographic measurement of cardiac output with automated software analyses of spectral curves in the left ventricular outflow tract has been introduced. This study aimed to assess the precision and accuracy of cardiac output measurements as well as the ability to track cardiac output changes over time comparing the automated echocardiographic method with the continuous pulmonary artery thermodilution cardiac output technique and the manual echocardiographic method in cardiac surgery patients. Cardiac output was measured simultaneously with all three methods in 50 patients on the morning after cardiac surgery. A second comparison was performed 90-180 min later. Precisions for each method were measured. Bias and limits of agreement (LoA) between methods were assessed and concordance- and polar plots were used for evaluating trending of cardiac output. When comparing the automated echocardiographic method with the thermodilution technique, the mean bias was 0.72 L/min with LoA - 1.89; 3.33 L/min corresponding to a percentage error of 46%. The concordance rate was 47%. The mean bias between the automated- and the manual echocardiographic methods was - 0.06 L/min (95% LoA - 2.33; 2.21 L/min, percentage error 42%). The concordance rate was 79%. The automated echocardiographic method did not meet the criteria for interchangeability with the thermodilution technique or the manual echocardiographic method. Trending ability was poor when compared to the continuous thermodilution technique, but moderate when compared to the manual echocardiographic method.Trial registry number: NCT03372863. Retrospectively registered December 14th 2017.

When appearances deceive: Echocardiographic changes due to common chest pathology.

Most indications for performing echocardiography focus on the evaluation of properties intrinsic to the heart. However, numerous extra-cardiac conditions indirectly convey changes to the echocardiographic appearance through alterations in the governing physiology. Pulmonary embolism increases pulmonary arterial pressure if a sufficient cross-sectional area of the pulmonary vascular bed is occluded. This may result in dilatation of the right ventricle and, in severe cases, concomitant early diastolic septal collapse into the left ventricle. Acute respiratory failure has been shown to yield a similar echocardiographic appearance in experimental conditions due to the resultant pulmonary vasoconstriction. Echocardiography in the presence of pulmonary disease can reveal underlying cardiac pathologies such as pulmonary hypertension that contribute to the clinical severity of respiratory distress. Positive pressure ventilation affects preload, afterload, and compliance of both ventricles. The echocardiographic net result cannot be uniformly anticipated, but provides information on the deciding physiology or pathophysiology. Mediastinal pathology including tumors, herniation of abdominal content, and pleural effusion can often be visualized directly with echocardiography. Mediastinal pathologies adjacent to the heart may compress the myocardium directly, thus facilitating echocardiographic and clinical signs of tamponade in the absence of pericardial effusion. In conclusion, many pathologies of extra-cardiac origin influence the echocardiographic appearance of the heart. These changes do not reflect properties of the myocardium but may well be mistaken for it. Hence, these conditions are essential knowledge to all physicians performing echocardiography across the spectrum from advanced cardiological diagnostics to rapid point-of-care focused cardiac ultrasonography.

Where are we heading with fluid responsiveness research?

PURPOSE OF REVIEW: Fluid responsiveness prediction is not always possible with well established dynamic approaches such as passive leg raising or pulse pressure variation in the ICU. The purpose of the present review is to summarize emerging alternative techniques for fluid responsiveness prediction in adult critically ill patients and discuss their methodology and applicability. In addition, the future role of fluid responsiveness prediction in the ICU is discussed. RECENT FINDINGS: Several new dynamic techniques have been investigated and they all contribute to the applicability of fluid responsiveness techniques. Although increasing the applicability, most of the emerging techniques still rely on ventilator setting changes in patients that are fully or almost fully adapted to the ventilator or require reliable flow monitoring, which prevents broad applicability. Yet, the mini/micro fluid challenges and the use of extrasystolic preload changes have the potential of being more applicable but all reviewed methods need further validation and methodological refinement. SUMMARY: Emerging techniques are encouraging for broader applicability of fluid responsiveness prediction. Still, the clinical impact of correctly predicting fluid responsiveness remains to be investigated in the critically ill and the research community should have a clear aim of moving toward that type of studies.

A successful model to learn and implement ultrasound-guided venous catheterization in apheresis.

BACKGROUND: Apheresis treatments can be performed with peripheral venous catheters (PVC), although central venous catheters (CVC) are inserted when PVCs fail or patient with history of difficult vascular access prior to the apheresis. Ultrasound guidance for PVC has shown promising results in other settings. PURPOSE: To investigate if ultrasound guidance for PVC could be implemented among apheresis nurses. Second, how implementation of ultrasound guidance affected the number of CVCs used for apheresis per patient. METHOD: Apheresis nurses completed a systematic training program for ultrasound-guided vascular access. All independent catheterizations were registered during the implementation stage. The number of CVCs in the pre- and postimplementation stages of the ultrasound guidance was compared. RESULTS: Six nurses completed the training program within a median of 48 days (range 38-83 days). In 77 patients, 485 independent ultrasound-guided PVC placements were performed during the implementation stage. All apheresis treatments (485/485) were accomplished using PVCs without requiring CVC as rescue. During the preimplementation stage, 125 of 273 (45.8%) procedures required a CVC for completion of apheresis procedures; during the postimplementation stage only 30 of 227 (13.2%) procedures required a CVC (p < 0.001). In the postimplementation stage, no CVCs were placed as rescue caused by failed PVCs but were only placed for patients where the ultrasound machine was unavailable. It indicates an effective success rate of 100% for ultrasound-guided PVC use. CONCLUSION: This study showed that ultrasound guidance could be implemented among apheresis nurses as a routine tool eliminating the need of CVC as a rescue.

Effects of Progressive Hypoventilation on Left Ventricular Appearance: An Alternative Etiology of Acute Sonographic Short-Axis D-Shaping.

OBJECTIVES: The purpose of this study was to evaluate the effects of progressive hypoventilation on echocardiographic measures of the left ventricular (LV) appearance in a porcine model. METHODS: Ten piglets were included in the experimental group, and 5 served as controls. The experimental group underwent 3 interventions of progressive hypoventilation (baseline: tidal volume, 240 mL; respiratory frequency, 16 minutes-1 ; first intervention: tidal volume, 240 mL; respiratory frequency, 8 minutes-1; second intervention: tidal volume, 240 mL; respiratory frequency, 4 minutes-1 ; and third intervention: tidal volume, 120 mL; respiratory frequency, 4 minutes-1 ). Respiratory resuscitation was initiated if the MAP decreased to 50% of the baseline level or at the end of the third intervention. Transthoracic sonography and invasive measurements were obtained throughout. The primary end point was the LV end-diastolic eccentricity index, a measure of LV D-shaping. RESULTS: The median LV end-diastolic eccentricity index increased from 1.1 (interquartile range, 1.0-1.1) at baseline to 1.4 (1.3-1.4) 3 minutes after the third intervention (P < .001) and returned to baseline after resuscitation (P = .093). The MAP declined from 87 mm Hg (81-92 mm Hg) to 50 mmHg (33-66 mm Hg) after initiation of the third intervention (P < .001). The mean pulmonary arterial pressure increased from 20 mm Hg (15-21 mm Hg) to 39 mm Hg (38-40 mm Hg) during the second intervention (P < .001). CONCLUSIONS: Progressive hypoventilation led to a marked D-configuration of the LV and a sharp decrease in systemic blood pressure. After respiratory resuscitation, sonographic measures normalized. These findings were explainable by the pressure changes observed within the left and right ventricles.

Dobutamine aggravates haemodynamic deterioration induced by pleural effusion: A randomised controlled porcine study.

BACKGROUND: Pleural effusion is a common finding in critically ill patients and may contribute to circulatory instability and the need for inotropic support. OBJECTIVE: We hypothesised that dobutamine would affect the physiological determinants preload, afterload, contractility and changes of inferior vena cava characteristics during experimental pleural effusion. DESIGN: A randomised, controlled laboratory study. SETTING: Animal laboratory, conducted from March 2013 to May 2013. ANIMALS: Twenty-four Landrace and Yorkshire female piglets (21.3 ±â€Š1.7 kg). INTERVENTION: Twenty piglets were included in the analyses. After inducing bilateral pleural effusion (30 ml kg), the piglets were block randomised to either incremental dobutamine infusion (n = 10) or control (n = 10). MAIN OUTCOME MEASURES: Ultrasonographic measures of left ventricular end-diastolic area, left ventricular afterload, left ventricular fractional area change and inferior vena cava diameter and distensibility were used to assess the basic physiological effect of incremental dobutamine administration during experimental pleural effusion. RESULTS: In the dobutamine group, preload, measured as left ventricular end-diastolic area, decreased from 11.3 ±â€Š2.0 cm after creation of the pleural effusion to 8.1 ±â€Š1.5 cm at a dobutamine infusion rate of 20 µg kg min (P < 0.001). In the same period, central venous pressure and the expiratory diameter of the inferior vena cava decreased from 9 ±â€Š3 to 7 ±â€Š4 mmHg (P < 0.001) and from 1.1 ±â€Š0.2 to 0.9 ±â€Š0.1 cm (P = 0.008), respectively. CONCLUSION: In a porcine model of pleural effusion, dobutamine affected basic haemodynamic determinants substantially by decreasing left ventricular preload. Changes in central venous pressure and inferior vena cava characteristics were minimal, discouraging their use as indices of preload. This study underlines the significance of evaluating basic haemodynamic determinants to avoid inappropriate, potentially harmful treatment.

Transthoracic echocardiography in the perioperative setting.

PURPOSE OF REVIEW: A need for further assessment of patients in the perioperative setting and an increasing availability of ultrasonography equipment have facilitated the diffusion of ultrasonography and lately focused transthoracic echocardiography (TTE) in anesthesiology practice. This review will discuss the possible use of focused TTE in the perioperative setting and provides an update on present and future perspectives. RECENT FINDINGS: Several studies focusing on patient management and diagnostic accuracy of perioperative, focused TTE, have been published recently. Several multidisciplinary guidelines addressing use and educational aspects of focused ultrasonography are available, yet guidelines focusing solely on the use in the perioperative setting are lacking. SUMMARY: Hemodynamically significant cardiac disease or pathophysiology can be disclosed using TTE. Focused TTE is feasible for perioperative patient management and monitoring and will be an inevitable and indispensable tool for the anesthetist. Future research should focus on the outcome of perioperative TTE performed by anesthetists, using rigorous study designs and patient-centered outcomes such as mortality and morbidity.