Clinical implications of hypothermic ventricular fibrillation versus beating-heart technique during cardiopulmonary bypass for pulmonary valve replacement in patients with repaired tetralogy of Fallot

OBJECTIVES

This study aimed to compare the effects of hypothermic ventricular fibrillation and beating-heart techniques during cardiopulmonary bypass (CPB) on postoperative outcomes after simple pulmonary valve replacement in patients with repaired tetralogy of Fallot (TOF).

METHODS

We retrospectively reviewed the data of 47 patients with repaired tetralogy of Fallot at a single institution, who received pulmonary valve replacement under the ventricular fibrillation or beating-heart technique without cardioplegic cardiac arrest during CPB between January 2005 and April 2015.

RESULTS

The patients were divided into fibrillation (n = 32) and beating-heart (n = 15) groups. On comparing these groups, the fibrillation group had a larger sinotubular junction (27.1 ± 4.6 vs 22.1 ± 2.4 mm), had a longer operation duration (396 ± 108 vs 345 ± 57 min), required more postoperative transfusions (2.1 ± 2.6 vs 5.0 ± 6.3 units) and had a higher vasoactive-inotropic score at intensive care unit admission (8.0 vs 10, all P < 0.05). Echocardiographic data indicated that the systolic internal diameter of the left ventricle was larger in the fibrillation group than in the beating-heart group immediately after surgery and at the 1-year follow-up. Major adverse cardiac events occurred in 3 cases, all from the fibrillation group. Among 7 patients from the fibrillation group with transoesophageal echocardiography data during CPB, 6 had fully opened aortic valves during fibrillation, causing flooding into the left ventricle and left ventricle distension.

CONCLUSIONS

The postoperative outcomes are worse with the ventricular fibrillation technique than with the beating-heart technique during CPB for pulmonary valve replacement in patients with repaired tetralogy of Fallot.

Myocardial Protective Effect of Antegrade Cardioplegic Cardiac Arrest Versus Ventricular Fibrillation During Cardiopulmonary Bypass on Immediate Postoperative and Mid-Term Left Ventricular Function in Right Ventricular Outflow Tract Surgery

The objective of this study is to examine the myocardial protective effect of antegrade cardioplegic cardiac arrest (ACC) versus ventricular fibrillation (VF) on short-term and mid-term left ventricular (LV) function in right ventricular outflow tract (RVOT) surgery. RVOT operations conducted from January 2006 to December 2015 were reviewed. The numbers of cases using ACC and VF were 71 and 49, respectively. Postoperative mortality and morbidity were compared between the two groups. Before and after propensity score matching, left ventricular ejection fraction (LVEF) and left ventricular end-systolic/end-diastolic diameter (LVESD/LVEDD) in echocardiography were measured immediately after operation and at mid-term follow-up between postoperative 6 and 24 months. There was no perioperative mortality or cerebrovascular accident. There was no statistically significant difference in the incidence of ventricular and atrial arrhythmia. In the overall patient group, LVESD was significantly decreased in the ACC group compared to the VF group immediately after operation (-0.65 ± 3.55 mm vs. 2.99 ± 4.98 mm, P = 0.001). Mid-term follow-up data demonstrated that LVEF at midterm was higher in the ACC group than in the VF group (64.80% ± 7.40% vs. 60.24% ± 7.93%, P = 0.022). However, the increased amount compared to preoperative value was not statistically significant (1.94% ± 12.65% vs. -2.94% ± 9.41%, P = 0.059). After propensity score matching, the LVEF was significantly improved in the ACC group compared to the VF group at the mid-term follow-up (6.16% ± 6.77% vs. -5.41% ± 9.05%, P = 0.001). Multiple linear regression model demonstrated that lower preoperative LVEF, ACC rather than VF, and exclusion of RVOT reconstruction procedure were positive prognostic factors for the improvement of LVEF at mid-term follow up. The results of this study suggest that myocardial protection using ACC is safe and may be more beneficial in LV function recovery up to the mid-term follow-up after pulmonary valve replacement and other RVOT procedures.

Acute Basilar Artery Occlusion: Differences in Characteristics and Outcomes after Endovascular Therapy between Patients with and without Underlying Severe Atherosclerotic Stenosis

BACKGROUND AND PURPOSE

Prediction of underlying intracranial atherosclerotic stenosis before endovascular therapy might be helpful for appropriate therapeutic planning in patients with acute ischemic stroke. This study aimed to compare the characteristics and treatment outcomes in patients with acute basilar artery occlusion relative to the existence or nonexistence of underlying intracranial atherosclerotic stenosis.

MATERIALS AND METHODS

Sixty-two patients with acute basilar artery occlusion underwent multimodal endovascular therapy. All patients underwent stent-retriever thrombectomy as a first-line endovascular therapy. Patients with underlying intracranial atherosclerotic stenosis underwent additional intracranial angioplasty and stent placement. The clinical and imaging characteristics and treatment outcomes were retrospectively analyzed and compared between patients with and without intracranial atherosclerotic stenosis.

RESULTS

Underlying intracranial atherosclerotic stenosis was identified at the occlusion site in 15 patients (24.1%). Occlusion in the proximal segment of the basilar artery was more common in patients with intracranial atherosclerotic stenosis (60% versus 6.4%, P < .001), whereas occlusion in the distal segment was more common in those without it (91.5% versus 26.7%, P < .001). Bilateral thalamic infarction on a pretreatment DWI was less common in patients with intracranial atherosclerotic stenosis (0% versus 27.7%, P = .027) compared with those without it. There were no significant differences in the rates of successful revascularization, favorable outcome, symptomatic hemorrhage, and mortality between the 2 groups.

CONCLUSIONS

Underlying intracranial atherosclerotic stenosis was not uncommon in patients with acute basilar artery occlusion. The occlusion segment of the basilar artery and the presence or absence of bilateral thalamic infarction on a pretreatment DWI might be helpful for predicting underlying intracranial atherosclerotic stenosis in patients with acute basilar artery occlusion. Patients with and without underlying intracranial atherosclerotic stenosis who underwent endovascular therapy had similar outcomes.

Prediction of the mid-tracheal level using surface anatomical landmarks in adults: Clinical implication of endotracheal tube insertion depth

Endotracheal tube (ETT) should be placed at the optimal level to avoid single lung ventilation or accidental extubation. This study was performed to estimate the mid-tracheal level by using surface anatomical landmarks in adult patients.Neck computed tomography images of 329 adult patients between the ages of 16 and 79 years were reviewed. In the midline sagittal plane, the levels corresponding to the vocal cords, cricoid cartilage, suprasternal notch, manubriosternal junction, and carina were identified. The surface distances from the cricoid cartilage to the suprasternal notch (extCC-SSN) and that from the suprasternal notch to the manubriosternal junction (extSSN-MSJ) were measured. The relationship between mid-tracheal level and the surface distances was analyzed using Bland-Altman plot.The difference between the extCC-SSN and the mid-tracheal level was -6.6 (12.5) mm, and the difference between the extSSN-MSJ and the mid-tracheal level was -19.2 (6.1) mm. The difference between the extCC-SSN and the mid-tracheal level was smaller in females compared with males [-1.7 (11.7) mm vs -12.8 (10.7) mm; P < 0.001].The mid-tracheal level, which is helpful in planning the insertion depth of an ETT, can be predicted by the surface distance between the cricoid cartilage and suprasternal notch in adults, especially in females.

Simple method for obtaining the optimal laryngoscopic view in children: A prospective observational study

BACKGROUND

Head and neck positioning has an important effect on laryngeal visualization during laryngoscopy. For small children and infants, a head-flat position is traditionally assumed; however, during laryngoscopy, the optimal head position may result in a superior laryngeal view in certain patients.

METHODS

We investigated whether the alignment of the external auditory meatus and the sternal notch with a pillow with an individualized height is associated with improved laryngeal visualization during direct laryngoscopy in pediatric patients. We enrolled 49 pediatric patients (3 to 6years old) receiving general anesthesia. The percentage of glottic opening score and ease of handling the laryngoscope (range 0-10) were recorded before and after head positioning with the pillow.

RESULTS

Most of the children, except two patients, needed a pillow beneath their head to align the external auditory meatus and the sternal notch. The percentage of glottic opening score was significantly higher after pillow adjustment compared to that in the neutral position (50 [20-80] vs. 90 [37.5-100]; p<0.0001). Handling of the laryngoscope improved with pillow adjustment (7 [6.0-8.0] vs. 9 [8.0-10.0]; p<0.0001). There were no significant complications during intubation.

CONCLUSIONS

Positioning of the head in order to align it with the external auditory meatus and sternal notch was associated with superior laryngoscopic visualization in pediatric patients. This resulted, in a more straightforward laryngoscopic procedure.

TRIAL REGISTRATIONS

http://cris.nih.go.kr identifier: KCT 0001156.

Deformation mechanisms to ameliorate the mechanical properties of novel TRIP/TWIP Co-Cr-Mo-(Cu) ultrafine eutectic alloys

In the present study, the microstructural evolution and the modulation of the mechanical properties have been investigated for a Co-Cr-Mo (CCM) ternary eutectic alloy by addition of a small amount of copper (0.5 and 1 at.%). The microstructural observations reveal a distinct dissimilarity in the eutectic structure such as a broken lamellar structure and a well-aligned lamellar structure and an increasing volume fraction of Co lamellae as increasing amount of copper addition. This microstructural evolution leads to improved plasticity from 1% to 10% without the typical tradeoff between the overall strength and compressive plasticity. Moreover, investigation of the fractured samples indicates that the CCMCu alloy exhibits higher plastic deformability and combinatorial mechanisms for improved plastic behavior. The improved plasticity of CCMCu alloys originates from several deformation mechanisms; i) slip, ii) deformation twinning, iii) strain-induced transformation and iv) shear banding. These results reveal that the mechanical properties of eutectic alloys in the Co-Cr-Mo system can be ameliorated by micro-alloying such as Cu addition.

Optimal Transducer Level for Atrial and Pulmonary Arterial Pressure Measurement in Patients with Functional Single Ventricle

This study aimed to investigate the optimal transducer level for accurate measurement of atrial and pulmonary arterial pressures in the supine position for patients with functional single ventricle. Contrast-enhanced chest computed tomographic images of 108 patients who underwent either the bidirectional cavopulmonary shunt (BCPS) placement or the Fontan procedure were reviewed. Vertical distances from the skin of the back to the uppermost levels of fluid in the single atrium or the pulmonary artery confluence and their ratios to the greatest anteroposterior (AP) diameter of the thoracic cage were determined. In patients who underwent BCPS, the ratios of the uppermost levels of blood in the atrium and pulmonary artery confluence to the greatest AP diameter of the thorax were 76.0 ± 8.1 and 56.3 ± 5.5 %, respectively. The distance (mm) between these two levels was calculated as 24.2 + 0.31 × age (years) (r ² = 0.08, P < 0.03). In patients who underwent the Fontan procedure, the ratios were 79.3 ± 10.0 and 58.3 ± 5.8 %, respectively. The distance (mm) between these two levels was calculated as 31.1 + 0.44 × age (years) (r ² = 0.05, P < 0.11). The optimal transducer levels for measuring atrial and pulmonary arterial pressures in the supine position are 75-80 and 55-60 % of the AP diameter of the thorax, respectively, in patients with functional single ventricle. We should consider the difference of the pressure when atrial and pulmonary arterial pressures were measured with the same level of transducers.

Reference Levels for Central Venous Pressure and Pulmonary Artery Occlusion Pressure Monitoring in the Lateral Position

OBJECTIVE

To investigate reference levels for central venous pressure or pulmonary artery occlusion pressure monitoring in a lateral position.

DESIGN

Retrospective observational study.

SETTING

A tertiary university hospital.

PARTICIPANTS

A total of 204 adults who underwent chest computed tomography scan in the 90° lateral position from November 2006 to February 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Distances from the mid-sternum to the uppermost and lowermost blood levels of both atria were measured. Ratios of the distance from the bottom of the thorax to the uppermost and the lowermost blood levels of both atria to the largest diameter of the thorax were calculated. There were significant differences between the distances from the mid-sternum to the uppermost and the lowermost blood levels of the right atrium and those of the left atrium in the right and left lateral positions, respectively. There were significant differences in the uppermost (3.3±0.1 cm; 95% confidence interval [CI] 3.1-3.5) and the lowermost (4.4±0.1 cm; 95% CI 4.2-4.7) blood levels of the right atrium between the right and left lateral positions. Although the uppermost (1.5±0.1 cm; 95% CI 1.3-1.8) and the lowermost (0.4±0.1 cm; 95% CI 0.2-0.6) blood levels of the left atrium between the right and left lateral positions showed differences, their extent was smaller than the right atrium. The uppermost and the lowermost blood levels of the right atrium lay lower than those of the left atrium in the 90° right lateral position. In contrast, in the 90° left lateral position, the uppermost and the lowermost blood levels of the right atrium lay higher than those of the left atrium.

CONCLUSIONS

When monitoring the central venous pressure and pulmonary artery occlusion pressure with patients in the lateral position, changes in the blood level of both atria should be considered when releveling the reference transducer.

Prediction of the midtracheal level based on external anatomical landmarks: implication of the optimal insertion depth of endotracheal tubes in pediatric patients

BACKGROUND

Optimal positioning of endotracheal tubes (ETTs) decreases the risk of accidental extubation or endobronchial intubation. This study evaluated the usefulness of external anatomical landmarks as practical references for determining an insertion depth of an ETT in pediatric patients.

METHODS

Computed tomography images of the necks of 183 pediatric patients (≤16 years of age) were reviewed. Levels corresponding to the vocal cords, cricoid cartilage, suprasternal notch, manubriosternal junction, and carina were identified on sagittal reconstructed images. The surface measurements from the cricoid cartilage to the suprasternal notch and that from the suprasternal notch to the manubriosternal junction were determined. Bland-Altman analysis was used to interpret the relationship between the midtracheal level and the surface measurements.

RESULTS

The difference between the midtracheal level and the surface distance from the cricoid cartilage to the suprasternal notch was 3.5 ± 7.0 mm, which was closer to zero than that between the midtracheal level and the surface distance from the suprasternal notch to the manubriosternal junction of 15.1 ± 6.1 mm.

CONCLUSION

The midtracheal level, helpful in planning the insertion depth of an ETT, can be predicted by measuring the surface distance from the cricoid cartilage to suprasternal notch in pediatric patients.

The influence of age on positions of the conus medullaris, Tuffier's line, dural sac, and sacrococcygeal membrane in infants, children, adolescents, and young adults

BACKGROUND

The purpose of this study was to analyze the distances between the conus medullaris and the Tuffier's line, and between the dural sac and the sacrococcygeal membrane (SCM) in the same pediatric population.

METHODS

Spinal magnetic resonance images and simple X-ray images of 350 patients aged from 1 month to 20 years were reviewed. Positions of the conus medullaris, Tuffier's line, the dural sac, and the SCM were identified. Each position was recorded in relation to the corresponding vertebral body segments. The distances between the conus medullaris and Tuffier's line, and between the dural sac and the SCM, were measured and then assessed according to age using an analysis of variance and a linear regression analysis.

RESULTS

The median levels of the conus medullaris and Tuffier's line were in the lower third of L1 [the first lumbar vertebral body] and the middle third of L5, respectively. The levels of the conus medullaris and Tuffier's line were lower in younger populations. The distance between the conus medullaris and Tuffier's line ranged from 1.5 to 4.75 vertebral body height. However, a narrow range of 1.5-2.5 vertebral height was observed only in children younger than 2 years. The level of the dural sac did not differ greatly by age, but the upper limit of the SCM was lower in older populations. The distance between the dural sac and the upper limit of the SCM increased with age.

CONCLUSIONS

In children, there is a distance of 1.5-4.75 vertebral body height between the conus medullaris and the Tuffier's line. However, these distances were narrower among younger populations. The distance between the dural sac and the upper limit of the SCM increased with age.

Production of RbCs Molecules in the Rovibronic Ground State via Short-Range Photoassociation to the 2 1 Π1 , 2 3 Π1 , and 3 3 Σ1+ States

We report the production of ultracold ⁸⁵ Rb¹³³ Cs molecules in their rovibronic ground state X ¹ Σ⁺ (v=0; J=0), by short-range photoassociation (PA) to the 2 ¹ Π₁ , 2 ³ Π₁ , and 3 ³ Σ1+ states. In the PA frequency range from 11650 to 12150 cm^-1 (corresponding to energy levels 15500-16000 cm^-1 above the bottom of the X potential), we have observed 40 sets of new PA lines. For selected PA states, we investigate vibrational branching, rotational branching, and saturation behavior. Among these 40 new PA lines, the 3 ³ Σ1+ (v=3) state has the highest molecule production rate of 2 x 10³  molecules s^-1 into the rovibronic ground state.

Effect of molecular weight of hyaluronic acid (HA) on viscoelasticity and particle texturing feel of HA dermal biphasic fillers

Background

Hyaluronic acid (HA) dermal biphasic fillers are synthesized for their efficacy in correcting aesthetic defects such as wrinkles, scars and facial contouring defects. The fillers consist of crosslinked HA microspheres suspended in a noncrosslinked HA. To extend the duration of HAs within the dermis and obtain the particle texturing feel, HAs are crosslinked to obtain the suitable mechanical properties.

Results

Hyaluronic acid (HA) dermal biphasic fillers are prepared by mixing the crosslinked HA microspheres and the noncrosslinked HAs. The elastic modulus of the fillers increased with raising the volume fraction of the microspheres. The mechanical properties and the particle texturing feel of the fillers made from crosslinked HA (1058 kDa) microspheres suspended in noncrosslinked HA (1368 kDa) are successfully achieved, which are adequate for the fillers.

Conclusions

Dermal biphasic HA fillers made from 1058 kDa exhibit suitable elastic moduli (211 to 420 Pa) and particle texturing feel (scale 7 ~ 9).

Optimizing Prone Cardiopulmonary Resuscitation: Identifying the Vertebral Level Correlating With the Largest Left Ventricle Cross-Sectional Area via Computed Tomography Scan

BACKGROUND

Placing the patient in the prone position frequently is required for some surgical procedures. If cardiac arrest occurs and the patient cannot be safely turned supine, cardiopulmonary resuscitation (CPR) may need to be performed with the patient in the prone position. Although clear landmarks have been defined for supine CPR, the optimal hand position for CPR in the prone position has not been clearly determined. The purpose of this study was to determine anatomically the optimal hand position for CPR in the prone position.

METHODS

We reviewed retrospectively the chest computed tomography images of 100 patients taken in the prone position. The vertebral body levels crossing the medial angle of the scapula, the inferior angle of the scapula, and the spinous process of the vertebral body connected to the most inferior rib were identified, and we selected the image level at which the left ventricular (LV) cross-sectional area was the largest. This level was defined as the optimal compression level and correlated to surface anatomical landmarks. We calculated the ratio of the distance from the C7 spinous process to the level of the largest LV cross-sectional area divided by the distance from the C7 spinous process to the spinous process of the vertebral body connected with the most inferior rib.

RESULTS

The level of the largest LV cross-sectional area in the prone position was 1 vertebral segment below the inferior angle of the scapula in 45% (99% confidence interval [CI], 33-58) of patients and 0 to 2 vertebral segments below that in 95% (99% CI, 86-98) of patients. The mean (SD) ratio of the distance from the C7 spinous process to the level of the largest LV cross-sectional area divided by the distance from the C7 spinous process to T12 spinous process was 67% ± 7% (99% CI, 65-69).

CONCLUSIONS

When the patient is positioned prone, the largest LV cross-sectional area is 0 to 2 vertebral segments below the inferior angle of the scapula in at least 86% of patients. Further studies are needed to determine whether this position is optimal for chest compressions in the prone position.

Estimation of the plasma effect site equilibration rate constant of sufentanil in children using the time to peak effect of heart rate and blood pressure

Objectives:

Although targeting the effect site concentration may offer advantages over the traditional forms of administering intravenous anesthetics, it is not applicable for sufentanil in children because its plasma effect site equilibration rate constant (k_e0) is not known yet. We estimated k_e0 of sufentanil in children using the time to peak effect (t_peak) method.

Materials and Methods:

Under general anesthesia, sufentanil t_peak was measured after administration of a submaximal bolus dose by means of the decrease in heart rate, blood pressure and calculated approximate entropy (ApEn) of electroencephalogram in 105 children (age range: 3–11 years). k_e0 was estimated using t_peak and known sufentanil pharmacokinetic parameters in normal children.

Results:

The mean t_peaks were measured as 44 ± 22 s and 227 ± 91 s by heart rate and by mean blood pressure respectively. The estimated k_e0 were 5.16/min and 0.49/min by heart rate and blood pressure respectively. t_peak could not be measured using the ApEn, thus k_e0 could not be calculated by ApEn in children.

Conclusions:

Shorter measured sufentanil t_peak by heart rate compared to blood pressure indicate that the heart rate decrease faster than decreasing of blood pressure. Moreover, the calculated sufentanil k_e0 in children depends on the pharmacodynamics parameters.

Critical incidents, including cardiac arrest, associated with pediatric anesthesia at a tertiary teaching children's hospital

BACKGROUND

Analysis of critical incidents provides valuable information to improve the quality and safety of patient care. This study identified and analyzed pediatric anesthesia-related critical incidents including cardiac arrests in a tertiary teaching children's hospital.

METHODS

All pediatric anesthesia-related critical incidents reported in a voluntary departmental reporting system between January 2008 and August 2013 were included in the analysis. A critical incident was defined as (i) any incident that altered patients' vital signs and affected the management of patients while they were under the care of an anesthesiologist, and (ii) human factor: where patient injury or accidents were as a result of human error. Changes in vital signs that recovered spontaneously were excluded.

RESULTS

During the 6-year study period, a total of 229 critical incidents were reported from 49,373 anesthetic procedures. The most frequently reported incidents were associated with the respiratory system (55%), with tracheal tube-related events accounting for 40.9% of respiratory incidents followed by laryngospasm (17.3% of respiratory incidents). Cardiac arrest occurred in 42 cases in this study (8.5 cases per 10,000 anesthetics). Cardiovascular problems were the major causes of cardiac arrest (66.7%), and incidents of cardiogenic shock and hemorrhage/hypotension contributed equally to the cardiac arrest induced by cardiovascular problems (each 16.7%). Human factor-related events accounted for 58.5% of all critical incidents of which 53.7% were respiratory events.

CONCLUSION

Despite recent improvements in safety of pediatric anesthesia, many preventable factors still remain that can lead to critical incidents.

Randomized controlled trial on preemptive analgesia for acute postoperative pain management in children

BACKGROUND

Preemptive analgesia is an anti-nociceptive treatment that starts before surgery and prevents the establishment of central sensitization. Whether preemptive analgesia is more effective than conventional regimens for managing postoperative pain remains controversial. This study evaluated the efficacy of intravenous preemptive analgesia for acute postoperative pain control in pediatric patients.

METHODS

In this prospective randomized controlled trial, 51 children aged 3-7 years, scheduled for corrective osteotomy were randomized into control (group C) or preemptive (group P) group. Both groups received standardized general anesthesia, including intravenous patient-controlled analgesia (IV-PCA) with fentanyl, which was started before skin incision in group P or 5 min thereafter in group C. IV-PCA data, pain scores using verbal rating scale (VRS) and Wong-Baker FACES(®) pain rating scale (WBFS), emergence agitation score (EAS) using the Pediatric Anesthesia Emergence Delirium (PAED) scale, analgesic requirements, and complications were recorded.

RESULTS

The primary outcome, pain score at postoperative 1 h, showed no difference between the groups. Both groups did not demonstrate emergence agitation (PAED cutoff value ≥ 12), although the EAS at admission to the postanesthetic care unit (PACU) was lower in group P than in group C (P = 0.002; mean difference 4.85, 95% CI 1.97-7.73). There were no differences in the delivered volume of IV-PCA, frequency of pushing the IV-PCA button, effective push attempts, VRS, WBFS, EAS at discharge from the PACU, additional analgesic requirements, and complications.

CONCLUSION

Preemptive analgesia using IV-PCA with fentanyl showed no significant advantages for postoperative analgesia after corrective osteotomy in pediatric patients.

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 <x/d <25) of a circular jet at Re ≈ 7,000. Lagrangian flow features and turbulence quantities in an Eulerian frame are estimated around ten diameters downstream of the jet origin and at various radial distances from the jet core. Lagrangian properties include trajectory, velocity and acceleration of selected particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

Influence of caudal traction of ipsilateral arm on ultrasound image for supraclavicular central venous catheterization

BACKGROUND

The first step for successful ultrasound (US)-guided subclavian vein (SCV) catheterization using a supraclavicular approach is to obtain a good longitudinal image of SCV for in-plane needle placement. We evaluated the efficacy of caudal traction of ipsilateral arm on the exposure of the SCV.

METHODS

We enrolled 20 infants, 20 children, and 20 adults undergoing general anesthesia. After tracheal intubation, US probe was applied as the supraclavicular approach, and the longitudinal US image of SCV was obtained in 3 different ipsilateral arm positions: neutral, caudal traction, and abduction. The length of puncturable SCV, the diameter of SCV, and the available angle for needle insertion in 3 different arm positions were analyzed.

RESULTS

In all patients, the length of puncturable SCV and the available angle for needle insertion were significantly increased after caudal traction (35.6% ± 27.1% and 25.0% ± 19.3%, respectively) and decreased after the abduction (36.6% ± 22.9% and 29.5% ± 23.8%, respectively) compared to neutral position. The diameter of SCV was not changed after applying the caudal traction in infants and children. However, in adults, the caudal traction slightly increased the diameter of SCV (P = .012).

CONCLUSION

The caudal traction of ipsilateral arm toward to the knee improves the longitudinal US view of SCV for the supraclavicular approach, without reducing its size. Proper caudal traction of the arm might ensure the high success rate with safe needle insertion technique. Abduction should be avoided during US-guided supraclavicular SCV catheterization.