Sonosite

Limb volume measurements, especially in the short term, provide a proxy measure of fluid changes. These were taken with an optoelectronic system (Perometer 400T; Pero-System Messgeräte GmbH, Wuppertal, Germany).^{3 (link),4 (link)}Extracellular fluid (ECF) changes in the whole limb were assessed by bioimpedance spectroscopy (BIS) of the individual lower limbs,^{5 (link)} measured as changes in electrical resistance at zero frequency (R₀) using an SFB7 impedance spectrometer (ImpediMed, Queensland, Australia) according to the protocol as described by Steele et al.^{6 (link)} Increases in R₀ values correspond proportionally to decreases in ECF.^{7 (link)}Local tissue water (LTW) was assessed by measuring tissue dielectric constant (TDC) with a Moisture Meter D (Delfin Technologies, Kuopio, Finland), at specific anatomical sites (on dorsum of foot, medial malleolus, below patella, above patella, inguinal ligament, and lower abdominal wall) using two probes that measure LTW to depths of 2.5 and 5 mm, respectively.⁸ Ultrasound with a 5–16 MHz probe (Fujifilm Sonosite, Bothell, WA, USA), was used to measure skin thickness at the same anatomical sites as TDC. Skin thickness (epidermis and dermis) has previously been shown to be increased uniformly around the arm in breast cancer-related lymphedema and correlates strongly with the degree of swelling.^{9 (link)}

Echocardiography was performed 24 h after the CLP using Vevo 3100 with a 400 MHz probe (FUJIFILM SonoSite, lnc. JAPAN). The mice (prior removal of hair from the precardiac region) were anesthetized with isoflurane inhalation and the limbs were fixed. The long axis section of the left ventricle was evaluated, and the left ventricle movement was detected with M-mode echocardiography. The following four parameters were measured: left ventricular end diastolic diameter (LVEDD), left ventricular end systolic dimension (LVESD), left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS). All data were processed under the same parameters and analyzed by investigator blinded to the experimental treatments. The value of each measurement index was the average value of three consecutive cardiac cycles.

Tongue ultrasonography was performed in Brightness mode using a portable ultrasound machine (M-Turbo; Fujifilm SonoSite, Tokyo, Japan) equipped with a convex transducer (5–10 MHz). All ultrasound examinations were performed by one well-trained examiner, with the participant in a relaxed, seated position. For measurement, the probe was placed underneath the chin, and the angle of the probe was positioned perpendicular to the Frankfurt horizontal plane at the first premolar area (Figure 1A,B) [7 (link),8 (link),9 (link)] using passive pressure. Echo gain was maintained at the same level for all measurements, which were obtained with the tongue in the resting position after swallowing saliva. This process was repeated thrice, and the mean of the three values was recorded for each measurement.
TT and EI measurements were analyzed using ImageJ (version 1.37, National Institutes of Health, Rockville, MD, USA). TT was measured from the dorsal surface of the tongue to the upper border of the geniohyoid muscle. A region of interest that included as much tongue muscle tissue as possible while avoiding the surrounding fascia was selected to determine EI (Figure 1C) [7 (link)]. The mean EI was measured via a histogram-based grayscale analysis, with values ranging from 0 (black) to 255 (white).

Four Canadian ICUs in Edmonton, Alberta, Canada, participated in this prospective, observational cohort study. All are tertiary care referral centers, caring for complex medical, trauma, surgical, oncologic, and transplant patients. All sites are equipped with portable ultrasound machines (Fujifilm Sonosite, Bothell, WA) with probes for TTE, TEE, and TCD. Following a point-of-care ultrasound (POCUS) study by the physician, images are saved and automatically uploaded to the Qpath (Telexy, Maple Ridge, BC, Canada) archiving system, along with a report charted from the scanning physician.
We recruited eligible all consecutive ARDS COVID and non-COVID patients between November 16, 2020, and September 1, 2021, who all received a protocolized hypoxemia shunt workup. Patients were included if they were diagnosed with ARDS who were receiving invasive mechanical ventilation plus COVID-19 pneumonia (comparator group) versus ARDS without COVID (control group). Patients were excluded if less than 18 years old.

Patients were placed in the lateral decubitus position (affected side on top, consistent with the surgical position). Routine skin disinfection was performed, and the T4 and T7 paravertebral spaces were located using a low-frequency convex array ultrasound probe (FUJIFILM Sonosite, Inc., Bothell, WA, USA). The puncture needle for nerve block was injected into the paravertebral space through the short-axis plane of the spine. If no air or blood was drawn, 15 and 20 ml of local anaesthetic mixture (including 0.375% ropivacaine and 0.125 mg/ml dexamethasone) were injected into the T4 and T7 paravertebral spaces, respectively. After the procedure, patients were assisted in transitioning from the lateral decubitus position to the supine position. The block plane was determined after a 20-min observation period. If skin pain and temperature sensation disappeared on the affected side and the block range covered at least the T4–T9 sensory plane segment, the block was considered successful and effective. An anaesthesiologist experienced in nerve block performed the UG-TPVB throughout the trial to ensure consistency.

LUS was performed using a portable ultrasound scanner (Fujifilm Sonosite Inc., Bothell, WA, USA) with a 2–5-MHz convex probe at the beginning and end of hemodialysis. A 28-position B-line score was adopted to calculate the cumulative number of B-lines as an expression of interstitial pulmonary congestion. Anterior and lateral chest scans were performed on both sides of the chest from the second to fourth (left side) or fifth (right side) intercostal spaces at the parasternal to mid-axillary lines. Two different physicians performed two examinations to assess intra- and interoperator concordance. Each operator was blinded to the clinical and bioelectrical impedance analysis data and ultrasonographic measurements performed by the other operator. A third experienced physician with high expertise in LUS evaluations recorded the data.

In a prone position, the TP of the 6th thoracic vertebra was identified using ultrasound with downward counting from the 1st rib. Following standard skin disinfection, a linear transducer (6-13 MHz HFL38x; Fujifilm SonoSite, Bothell, WA) was placed parallel to the thoracic spine to visualize the 6th TP, and an 18G Tuohy needle was inserted by the in-plane technique, in a caudad to cephalad direction. After the needle tip touched the 6th TP, 10 mL of normal saline was applied to confirm spreading to the deep part of the erector spinae muscle and to make space for catheter insertion. Then, a multi-orifice catheter was implanted 3 cm beyond the needle tip. The anesthesiologist checked the location of the catheter tip by fluoroscopy. A loading dose of 20 mL 0.375% ropivacaine was injected 30 minutes before the end of surgery. A programmed intermittent bolus infusion (PIBI) of 15 mL 0.2% ropivacaine every 3 h was started 3 h after injecting the loading dose (20 mL) using a PCA pump with a 5 mL bolus and a lock-out interval of 20 minutes for 2 postoperative days.