Peter Juhl-Olsen

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Background: Accurate cardiac output assessment is crucial for evaluating hemodynamic status and guiding therapeutic interventions. The fourth generation FloTrac software (the FloTrac method) provides minimally invasive, continuous, and real‐time cardiac output estimations. This study aimed to evaluate the accuracy, precision, and trending performance of cardiac output measurements using the FloTrac method compared to bolus thermodilution cardiac output derived from a pulmonary artery catheter (the thermodilution method).Methods: This prospective clinical interventional study included 41 cardiac surgery patients from September 2023 to September 2024 at Aarhus University Hospital, Denmark. Cardiac output was measured simultaneously using both the FloTrac method and thermodilution method, before and after two preload‐increasing interventions: a modified Trendelenburg maneuver and a fluid bolus administration. Bias, limits of agreement, and percentage error between the methods were assessed for each time point. Trending ability was evaluated using four‐quadrant plots and concordance rates. Interchangeability of the two methods was accepted with a bias within the range of ±0.5 L/min, PE < 30%, and concordance rates ≥ 90%.Results: Bias ranged from −0.36 to 0.79 L/min depending on the intervention, with consistently wide limits of agreement. Percentage errors were 37% and 35% before and after fluid administration, and 37% and 42% before and after the Trendelenburg maneuver. The concordance rate was 85% after fluid administration and 72% after the modified Trendelenburg maneuver. The FloTrac method identified fluid responders with a sensitivity of 23% and specificity of 84% with the thermodilution method as reference.Conclusion: The FloTrac method did not meet the criteria for interchangeability with the thermodilution method for measuring cardiac output in patients after cardiac surgery. Percentage errors were unacceptable for all time points.Editorial Comment: This study assessed an updated version of the FlowTrac cardiac output estimation system, comparing results in clinical cases with some modest preload variation to same time cardiac output measurement with pulmonary artery‐based thermodilution measurements. The findings showed that there was limited agreement between these two methods in these settings, suggesting that they do not appear to be interchangeable.

Background: Video‐assisted thoracoscopic surgery (VATS) is widely used in lung cancer surgery, as this technique causes less pain and faster recovery than open thoracotomy. However, significant postoperative pain persists in a number of patients, often leading to increased opioid use and opioid‐related adverse events in addition to prolonged admission times. Perioperatively administered glucocorticoids have been demonstrated effective in reducing pain after other types of surgeries, but the effect in VATS remains unclear.Methods: This systematic review will assess the impact of glucocorticoids on postoperative pain in adult patients undergoing VATS. We will include randomised trials comparing higher doses of glucocorticoids to lower doses, placebo or no treatment. The review will follow the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis statement and Cochrane methodology. The certainty of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation system. The primary outcome is standardised dynamic pain scores within 24 h. Secondary outcomes are opioid use, time to first mobilisation, length of hospital stay and numeric rating score >3 at any point within the first 24 h following surgery. Exploratory outcomes are opioid‐related adverse effects and glucocorticoid‐related adverse effects classified in major and minor events. Data will be meta‐analysed with sensitivity and subgroup analyses and trial sequential analyses. Furthermore, we will assess the risk of reporting bias and heterogeneity.Conclusion: This systematic review and meta‐analysis will provide an overview of the current evidence of how glucocorticoids affect postoperative pain and recovery in adult patients undergoing VATS.

To systematically evaluate the effect of small changes in transducer position on key hemodynamic variables including CO generated by 4th generation FloTrac software. After cardiac surgery, cardiac output, mean arterial pressure, systemic vascular resistance, and stroke volume variation were measured with 4 generation Flotrac software. The transducer position was randomly placed at the midaxillary plane, 4 cm higher than the midaxillary plane or 4 cm lower than the midaxillary plane. Averages of three measurements were used. Data was available from 20 patients. Cardiac output increased from 4.59 L/min (± 0.92) to 4.78 L/min (± 0.99) with the transducer position at the midaxillary plane to 4 cm higher than the midaxillary plane, and cardiac output decreased to 4.43 L/min (± 0.90) with the transducer 4 cm lower than midaxillary plane (P < 0.001). On the relative scale, CO increased 4.1% (95% CI 3.1-5.0) when comparing the higher transducer level with the midaxillary plane position, and CO decreased 3.4% (95% CI 2.4–4.4) when comparing the midaxillary plane position with the lower transducer level, correspondiong to changes in CO of ≈ 1% per 1 cm change in transducer position. Mean arterial pressure and systemic vascular resistance both changed significantly with transducer position (both P < 0.001), whereas no statistically or clinically significant effect was seen on stroke volume variation (P = 0.98). A four-centimeter change in vertical transducer position induced clinically significant changes in cardiac output measurements by 4th generation FloTrac software. Definitions of optimal cardiac output in goal-directed therapy algorithms require meticulous transducer adjustment and can only be used in the reference patient position.

Background: Intravenous therapies are essential for hospitalised patients. The rapid dissemination of portable ultrasound machines has eased ultrasound‐guided intravenous access and facilitated increased use of long peripheral venous catheters (LPCs). This study aimed to evaluate the clinical performance and complications of LPCs.Methods: Retrospective, observational single‐site study. Data from all consecutively inserted LPCs during a period of 18 months was evaluated. The primary endpoint was the all‐cause incidence rate of catheter removal. Secondary endpoints included specific reasons for the catheter removal and the associations between predefined characteristics of the patients, the infusions and the catheters with catheter failure.Results: During the period, 751 PVCs were inserted in 457 patients. The reasons for catheter removal were recorded in 563 cases. The overall incidence rate of catheter removal was 95.8/1000 catheter days (95% CI 88.4–103.8). The median dwell time was 8 days (IQR 5–14), and the total dwell time was 6136 days. Catheter failure occurred in 283 (50.3%) cases, of which the most common cause was phlebitis (n = 101, 17.9%). In multivariable analyses, the use of the cephalic vein was significantly associated with both all‐cause catheter failure (p < .001) and catheter failure due to phlebitis (p < .001). In multivariable analyses, vancomycin infusion was not significantly associated with all‐cause catheter failure (HR 1.15 (0.55–2.42), p = .71) or catheter failure due to phlebitis (HR 1.49 (0.49–4.53), p = .49).Conclusion: The overall incidence rate of catheter removal was 95.8/1000 catheter days, and the most common causes of catheter failure were phlebitis, infiltration and unintended catheter removal. The use of the cephalic vein was significantly associated with catheter failure in multivariable analyses. We did not find an association between vancomycin infusion and catheter failure in multivariable analyses.

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 (ICC_ear = 0.89 [95% CI 0.80; 0.94]; ICC_forehead = 0.77 [95% CI 0.60; 0.87]), while a modest reliability was found using the finger probe (ICC_finger = 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).

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 (V_T) or low heart-rate-to-respiratory-rate ratio (HR/RR). We investigated the effects of V_T 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 V_T from 4 to 10 ml kg⁻¹ and RR from 10 to 31 min⁻¹. For each of 10 RR-V_T 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 V_T. Higher RR was associated with lower PPV. Classically derived PPV was affected more by RR than GAM-derived PPV. Correcting PPV for V_T 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.

Background The 6-Minute Walk Test (6MWT) is a standardised method routinely used to screen for and monitor interstitiel lunge disease and/or pulmonary arterial hypertension in patients with systemic sclerosis (SSc). Studies shows that esaturations during the 6MWT are associated with severity of pulmonary manifestations in patients with SSc ^[1]. Digital sensors are commonly used to measure peripheral oxygen saturation (SpO₂) during the 6MWT. However, digital-based sensors may have important limitations in patients with SSc due to disease-related microangiopathy, Raynaud’s phenomenon, sclerodactyly and motion artifacts during the 6MWT ^[2]. Sensors located at more central body positions may therefore be more accurate as these as less prone to Raynaud attacks. Objectives To determine the validity and re-test reliability of peripheral oxygen saturation measured at the finger, forehead, and ear during the 6MWT in patients with SSc. Methods 82 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. We used Bland-Altman plots to display the agreement between SpO₂ and SaO₂, and between the minimal SpO₂ (minSpO₂) one week apart. The intraclass correlation coefficient (ICC, 95% confidence interval 95% CI]) for repeated measurement of minSpO2 was calculated. Results The mean difference (SpO₂ - SaO₂, ± standard deviation [SD]) after the 6MWT was –3.3% (±4.82), 0.15% (±1.55), and 1.36% (±1.93) for the finger, forehead, and earlobe, respectively (Table 1). The finger minSpO₂ also demonstrated the poorest re-test reliability: The mean difference in minSpO₂ (visit2-visit1, ±SD) was 1.28% (±5.3), 0.74% (±4.36) and –1.10% (±2.87),). The ICC (95% CI) showed good agreement using the ear and forehead probe (ICC_ear = 0.89 [0.80; 0.94]; ICC_forehead = 0.88 [0.60; 0.87]), while a modest reliability was found using the finger probe (ICC_finger = 0.65 [0.43; 0.80]). Conclusion Peripheral oxygen saturation should be measured using either the earlobe or forehead during the 6MWT in patients with SSc. References [1]Villalba, W. O. et al. Six-minute walk test for the evaluation of pulmonary disease severity in scleroderma patients. Chest 131, 217–222 (2007). [2]Pathania, Y. S. Alternatives for erroneous finger probe pulse oximetry in systemic sclerosis patients during COVID-19 pandemic. Rheumatol. Int. 41, 2243–2244 (2021). Validity and re-test reliability of peripheral oxygen during the 6MWT (n= 82) Acknowledgements: NIL. Disclosure of Interests Amanda Lynggaard Riis: None declared, Esben Naeser Paid instructor for: Boehringer Ingelheim Denmark, Katja Thorup Aaen: None declared, Henrik Hovgaard: None declared, Peter Juhl-Olsen: None declared, Elisabeth Bendstrup Speakers bureau: Hoffman-la-Roche. Boehringer Ingelheim. Glaxo Smith Kleine. Daichii Sankyo, Klaus Soendergaard Speakers bureau: Boehringer Ingelheim, Consultant of: Boehringer Ingelheim, Grant/research support from: Boehringer Ingelheim.