Anesthetic Management during Electroconvulsive Therapy / 이화의대지

Some patients with depression require electroconvulsive therapy performed undergeneral anesthesia. This requires rapid loss of consciousness, with minimal interferencefrom seizure activity, appropriate muscle relaxation status, prevention of hyperdynamicresponses to the electrical stimulus, and proper recovery of spontaneous ventilationand consciousness. The authors report the first case of electroconvulsive therapy performedwith the patient under general anesthesia at the Ewha Womans UniversityMedical Center, Korea.

Factors Affecting Maternal and Fetal Outcomes of Non-Obstetric Surgery and Anesthesia during Pregnancy: a Retrospective Review of Data at a Single Tertiary University Hospital

Background@#Anesthesia during pregnancy for non-obstetric surgery is generally known to have a negative impact on maternal and fetal outcomes. We assessed the risk of adverse outcomes in fetuses and mothers associated with non-obstetric surgery. @*Methods@#This retrospective study analyzed clinical data on pregnant women who received non-obstetric surgeries at a tertiary university hospital. We reviewed maternity admissions using hospital administrative data during the last 16 years. The outcome assessment included the presence of preterm labor, premature birth, abortion, or stillbirth and the data of newborns. Statistical analyses were performed using the t-test, χ2 test, and multiple logistic regression was used for risk analysis. @*Results@#The incidence of non-obstetric surgery during pregnancy was 0.96%. Gestational age at or above 20 weeks increased the risk of all adverse events 4.5 fold when it was compared to gestational age less than 20 weeks, although the events were only preterm labor or premature birth and no fetal loss. All fetal loss cases occurred in patients at less than 20 weeks of pregnancy. The risk of adverse outcome increased by 2% for every 1 minute increase in anesthesia time. Babies of the mothers who had the adverse outcome event showed lower birth weight and higher neonatal intensive care unit admission rate than those of babies of the mothers without any adverse event after the surgery. @*Conclusion@#Physicians should acknowledge and prepare for common possible adverse events at the stage of pregnancy after non-obstetric surgery, and effort to shorten the duration of surgery and anesthesia is needed.

The Skin-to-epidural distance of parturients by ultrasonography: sitting position versus left lateral position

BACKGROUND: Pre-procedural lumbar ultrasound scanning is a reliable tool to estimate the skin to epidural distance (SED). We conducted an observational study to compare the SED between the sitting position and lateral position using pre-procedural ultrasound imaging of the lumbar spine in parturients. METHODS: Using a 2–5 MHz curvilinear transducer, we obtained images of the lumbar interspaces from L2-3 to L5-S1 in the paramedian sagittal oblique view. The individual distance from the skin to the ligamentum flavum-dura mater unit was measured at the level of L2-3, L3-4, L4-5, and L5-S1 in the left lateral position (distance in lateral position; D-lat). Subsequently, participants were placed in the sitting position, and the distance was measured in the same manner (distance in sitting position; D-sit). Data were grouped according to body mass index (BMI; kg/m²) measurements of ≥ 25 or < 25 and analyzed. The primary outcome was the change determined by ultrasound between D-lat and D-sit at the same lumbar level according to position. RESULTS: Thirty parturients were studied. The difference between D-lat and D-sit in the same lumbar level was not statistically significant. The mean changes between D-lat and D-sit in the same lumbar level were less than 0.18 cm. In BMI ≥ 25 group, the difference between D-lat and D-sit were greater than that of BMI < 25 group at L3-4 level (P = 0.042). CONCLUSIONS: It is important for clinicians to consider that position change is associated with greater differences in SED in obese parturients (BMI ≥ 25) compared with thin parturients (BMI < 25). For obese parturients, the sitting position may be helpful.

Anesthetic Experiences of Liver Transplantation in a New Low Volume Hospital: Ewha Womans University Mokdong Hospital / 이화의대지

OBJECTIVES: Liver transplantation (LT) is the only treatment for end stage of liver failure. In Korea, annually it has been performed 1,300 cases. Most of LTs are performed in large volumes centers. More than half of centers performing LT in Korea are low volume hospital and started a LT program recently. We present our four-year experiences and outcomes of anesthesia for LT since 2013. METHODS: Anesthetic and surgical outcomes of 49 consecutive patients who received LT (living donor LT, 21 cases; deceased donor LT, 28 cases) between April 2013 and April 2017 were analyzed retrospectively. RESULTS: All patients were adult, with the mean age of 53.5±9.2 years. The most common cause of original liver diseases was hepatitis B virus-related liver cirrhosis (40.8%). The mean MELD (Model for End-stage Liver Disease) score was 18.8±10.7. Postreperfusion syndrome was observed in 34.7%, which were all controlled by calcium, norepinephrine, ephedrine and epinephrine. The mean postoperative intensive care unit stay of deceased donor LT recipients (13.6±9.0 days) was significantly longer than that of living donor LT recipients (8.0±3.3 days). There was no intraoperative mortality in patients receiving LT. Thirty-day post-transplant survival rate was 93.8% and 3-year survival rate was 88.6 %. The most common postoperative complication was pneumonia. CONCLUSION: We have started LT successfully with multidisciplinary team's steady effort. Adaptation and setting up LT protocol, adequate equipment, proper training at established transplant centers are essential to begin a successful LT program.

Hypoesthesia of the Cutaneous Branch of Cervical Plexus after Shoulder Arthroscopy under General Anesthesia with Ultrasound Guided-Interscalene Block / 이화의대지

We present an uncommon case of hypoesthesia in the posterior and upper third of the superior area on the left ear auricle, after arthroscopic surgery of the shoulder in the lateral position under general anesthesia with ultrasound guided-interscalene brachial plexus block. A 65-year-old man underwent arthroscopic rotator cuff repair of the left shoulder in the right lateral decubitus position. Two days after operation, he complained of numbness around the left auricle; his symptoms persisted until 6 weeks after surgery. Audiometry and sensory examinations were normal. He recovered naturally by 6 months postoperatively. Postoperative neurological deficits that may not be block-related can be attributed to a combination of factors, such as patient-, anesthesia-, and surgery-related factors, including direct trauma, positioning, and retraction. Anesthesiologists should be aware that the injury may not be block-related and consider other possible causes.

Ultrasound measurement of the vertebral level of Tuffier's line in elderly women / 대한마취과학회지

BACKGROUND: It would be imprecise to generalize the vertebral level determined by palpation to patients of all ages. The purpose of this study was to compare the vertebral level passed by Tuffier's line in elderly women with that passed in adult women using ultrasound in the left lateral decubitus flexed position. METHODS: We enrolled 50 female patients over the age of 65 (elderly group) and 50 female patients between ages 20 and 50 (control group) who had been scheduled to undergo spinal anesthesia. Using ultrasound, we marked the L2–5 lumbar spinous processes and intervertebral spaces. The most cephalad part was labeled 1 and the most caudal part was labeled 11. We then identified which line of these vertebral levels Tuffier's line crossed. RESULTS: The median value of the numbers signifying the vertebral level of Tuffier's line was 3 (the L2–3 intervertebral space) in the elderly group, while it was 8 (the lower part of the L4 vertebra) in the control group. The vertebral level of Tuffier's line had statistically significant correlations with age, body mass index, and weight in the elderly group (P < 0.001). CONCLUSIONS: The vertebral level of Tuffier's line determined with ultrasound measurement in the left lateral decubitus flexed position was more cephalad in the elderly women than in those of the control group. Therefore, we should consider that the needle could be inserted at a higher level than expected, and use care in determining the level of needle insertion during spinal anesthesia in elderly women.

Effect of Propofol and Desflurane on Immune Cell Populations in Breast Cancer Patients: A Randomized Trial

Several factors can affect the perioperative immune function. We evaluated the effect of propofol and desflurane anesthesia on the surgery-induced immune perturbation in patients undergoing breast cancer surgery. The patients were randomly assigned to receive propofol (n = 20) or desflurane (n = 20) anesthesia. The total and differential white blood cell counts were determined with lymphocyte subpopulations before and 1 hr after anesthesia induction and at 24 hr postoperatively. Plasma concentrations of interleukin (IL)-2 and IL-4 were also measured. Both propofol and desflurane anesthesia preserved the IL-2/IL-4 and CD4+/CD8+ T cell ratio. Leukocytes were lower in the propofol group than in the desflurane group at 1 hr after induction (median [quartiles], 4.98 [3.87-6.31] vs. 5.84 [5.18-7.94] 10(3)/microL) and 24 hr postoperatively (6.92 [5.54-6.86] vs. 7.62 [6.22-9.21] 10(3)/microL). NK cells significantly decreased 1 hr after induction in the propofol group (0.41 [0.34-0.53] to 0.25 [0.21-0.33] 10(3)/microL), but not in the desflurane group (0.33 [0.29-0.48] to 0.38 [0.30-0.56] 10(3)/microL). Our findings indicate that both propofol and desflurane anesthesia for breast cancer surgery induce a favorable immune response in terms of preservation of IL-2/IL-4 and CD4+/CD8+ T cell ratio in the perioperative period. With respect to leukocytes and NK cells, desflurane anesthesia is associated with less adverse immune responses than propofol anesthesia during surgery for breast cancer. (Clinical trial registration at https://cris.nih.go.kr/cris number: KCT0000939)

Hydrothorax with alveolar-pleural fistula mimicking re-expansion pulmonary edema during liver transplantation: a case report / 대한마취과학회지

We present a case of an alveolar-pleural fistula with hepatic hydrothorax in a patient undergoing orthotropic liver transplantation, which was detected by drainage of transudate through an endotracheal tube during operation. A standard endotracheal tube was changed to a double-lumen tube to provide differential lung ventilation. The patient was diagnosed with an alveolar-pleural fistula by direct vision of an air leak during positive-pressure ventilation through a diaphragmatic incision. There was still a concern about worsening his ventilation due to persistent aspiration of pleural effusion towards the ipsilateral lung during the remaining operation period. Surgeon repaired the defect on the exposed lung surface via diaphragmatic opening. Anesthesiologists should consider an alveolar-pleural fistula as a possible differential diagnosis with re-expansion pulmonary edema when transudate emanating from the endotracheal tube is obtained in patients with massive hydrothorax.

The degree of labor pain at the time of epidural analgesia in nulliparous women influences the obstetric outcome / 대한마취과학회지

BACKGROUND: The increased pain at the latent phase can be associated with dysfunctional labor as well as increases in cesarean delivery frequency. We aimed to research the effect of the degree of pain at the time of epidural analgesia on the entire labor process including the mode of delivery. METHODS: We performed epidural analgesia to 102 nulliparous women on patients' request. We divided the group into three based on NRS (numeric rating scale) at the moment of epidural analgesia; mild pain, NRS 1-4; moderate pain, NRS 5-7; severe pain, NRS 8-10. The primary outcome was the mode of delivery (normal labor or cesarean delivery). RESULTS: There were significant differences in the mode of delivery among groups. Patients with severe labor pain had a significantly higher cesarean delivery compared to patients with moderate labor pain (P = 0.006). The duration of the first and second stage of labor, fetal heart rate, use of oxytocin and premature rupture of membranes had no differences in the three groups. CONCLUSIONS: Our research showed that the degree of pain at the time of epidural analgesia request might influence the rate of cesarean delivery. Further research would be necessary for clarifying the mechanism that the augmentation of pain affects the mode of delivery.

Is small tidal volume with low positive end expiratory pressure during one-lung ventilation an effective ventilation method for endoscopic thoracic surgery? / 대한마취과학회지

BACKGROUND: The present study will focus on the rationale for the use of small tidal volume with 6 cmH2O positive end expiratory pressure (PEEP) with the changes of arterial oxygen tension, plateau airway pressure, and static lung compliance during one lung ventilation for endoscopic thoracic surgery. METHODS: Forty-three patients were intubated with a double-lumen endobronchial tube. After positioning the patients in the lateral decubitus, one-lung ventilation was started with 100% oxygen, tidal volume 10 ml/kg without PEEP; arterial oxygen tension, plateau airway pressure, and static compliance were checked as baseline values (T0). Fifteen minutes later, same parameters were measured (T15). The tidal volume had changed to 6 ml/kg with 6 cmH2O PEEP. Fifteen minutes later, the same parameters were measured (T30). RESULTS: Oxygen tension had decreased at T15 (282.1 +/- 83.4 mmHg) compared to T0 (477.2 +/- 82.4 mmHg) (P < 0.0001), but was maintained at T30 (270.4 +/- 81.9 mmHg). There was no difference in peak inspiratory pressure at T15 or T30 compared to T0, plateau airway pressure was increased at T15 and T30 (P < 0.05) and static lung compliance was decreased at T15 and T30 (P < 0.0001). CONCLUSIONS: In carrying out one-lung ventilation for thoracic surgery using an endoscope, the addition of a PEEP of 6 cmH2O in the dependent lung, while reducing the tidal volume of 6 ml/kg, both oxygen tension and lung compliance are maintained without increasing the plateau airway pressure. Protective lung ventilation is useful for one lung ventilation.

Does Intravenous Ketamine Enhance Analgesia after Arthroscopic Shoulder Surgery with Ultrasound Guided Single-Injection Interscalene Block?: A Randomized, Prospective, Double-Blind Trial

Ketamine has anti-inflammatory, analgesic and antihyperalgesic effect and prevents pain associated with wind-up. We investigated whether low doses of ketamine infusion during general anesthesia combined with single-shot interscalene nerve block (SSISB) would potentiate analgesic effect of SSISB. Forty adult patients scheduled for elective arthroscopic shoulder surgery were enrolled and randomized to either the control group or the ketamine group. All patients underwent SSISB and followed by general anesthesia. During an operation, intravenous ketamine was infused to the patients of ketamine group continuously. In control group, patients received normal saline in volumes equivalent to ketamine infusions. Pain score by numeric rating scale was similar between groups at 1, 6, 12, 24, 36, and 48 hr following surgery, which was maintained lower than 3 in both groups. The time to first analgesic request after admission on post-anesthesia care unit was also not significantly different between groups. Intraoperative low dose ketamine did not decrease acute postoperative pain after arthroscopic shoulder surgery with a preincisional ultrasound guided SSISB. The preventive analgesic effect of ketamine could be mitigated by SSISB, which remains one of the most effective methods of pain relief after arthroscopic shoulder surgery.

Hypertensive crisis during percutaneous radiofrequency ablation of a metastatic adrenal tumor under general anesthesia: A case report

Radiofrequency ablation (RFA) has been used as an alternative method of surgical treatment to treat neoplasms of variable body organs. In considerable proportion of RFA cases, anesthesiologists are asked to conduct general anesthesia. RFA has been known to be a safe and effective treatment, however injury to adjacent normal tissue during RFA develops serious complications. In particular, unintended injury to normal adrenal tissue of adrenal tumors can cause severe complications such as hypertensive crisis due to excessive secretion of catecholamine. However, serious complications of primary or metastatic adrenal tumors have been rarely reported due to RFA. We report a case of hypertensive crisis with associated tachycardia and ventricular arrhythmia during RFA of hepatocellular carcinoma metastatic to the adrenal gland.

Polyuria during Sevoflurane Anesthesia for Parotidectomy Patient / 이화의대지

Polyuria is occasionally observed during general anesthesia. Usually urine output during general anesthesia is decreased because of anesthetic agents. The authors came across with a case of polyruia during sevoflurane anesthesia which occurred after induction of anesthesia. Polyuria is a nonspecific symptom, but can cause many serious complications. Therefore, it is very important to investigate the cause thoroughly and treat patient appropriately.

The analgesic efficacy of ultrasound-guided transversus abdominis plane block with 2% lidocaine in early postoperative period after lower abdominal surgery

BACKGROUND: Transversus abdominis plane (TAP) block is a new regional anesthetic technique for postoperative pain control after lower abdominal surgery. We evaluated the analgesic efficacy of ultrasound-guided (US-) TAP block in patients undergoing lower abdominal surgery. METHODS: Thirty American Society of Anesthesiologists physical status I or II patients between 20-80 years of age undergoing lower abdominal surgery were randomized to receive standard care (n = 15) including intravenous patient-controlled analgesia (IV-PCA), or to undergo bilateral US-TAP block adjunctively (n = 15). A standard general anesthetic technique was used. After induction of anesthesia, bilateral US-TAP block was performed using total 30 ml of 2% lidocaine. Each patient was assessed postoperatively at 20, 30, and 60 min in postanesthesia care unit (PACU) and at 6, 12, and 24 h in ward for pain scores using verbal numerical rating scale (VNRS), analgesic requirements, quality of sleep, and complications. RESULTS: US-TAP block significantly reduced VNRS pain scores at 20, 30, and 60 min postoperatively (P < 0.001). The US-TAP block group required significantly fewer remifentanil intraoperatively (P < 0.05). Additional analgesic requirements were significantly lower in both PACU and ward (P < 0.05) in the US-TAP block group. There were no statistically significant between-group differences in total infused volume of IV-PCA, time to first requirement of analgesics in ward, and quality of sleep. CONCLUSIONS: US-TAP block with 2% lidocaine provided superior analgesia after lower abdominal surgery especially in the first 60 postoperative min when used as a component of a multimodal analgesic regimen.

Effect-site target-controlled infusion of propofol: comparison of Schnider and modified Marsh models

BACKGROUND: We investigated effect-site concentrations of propofol, changes in blood pressure and heart rate, time to loss of consciousness, time to loss of eyelid reflex and awakening time during anesthesia using effect-site target-controlled infusion, to compare the differences between Schnider and modified Marsh model. METHODS: Forty American Society of Anesthesiologists (ASA) physical status I or II patients between the ages of 18 and 55 years old and who were scheduled for elective surgery under general anesthesia were enrolled in this study. The patients were randomized into two groups: one group using modified Marsh model (Group 1) and the other group using Schnider model (Group 2). Effect-site concentrations of propofol, blood pressure, heart rate and BIS at each anesthetic stage were recorded. Time to loss of consciousness, time to loss of eyelid reflex and awakening time were measured. RESULTS: Group 1 showed shorter time to loss of consciousness and eyelid reflex at the lower effect-site concentration of propofol than Group 2 (P < 0.05). The effect-site concentrations of Group 1 were higher than those of Group 2 at eye opening and extubation (P < 0.05). CONCLUSIONS: Induction of anesthesia is achieved at lower effect-site concentration of propofol and more rapidly in the modified Marsh model than in the Schnider model. However the effect-site concentrations of propofol for awakening are higher in the modified Marsh model than in the Schnider model.

The effect of Trendelenburg position and pneumoperitoneum on regional cerebral oxygen saturation during gynecological laparoscopic surgery

BACKGROUND: The Trendelenburg positon and pneumoperitoneum for gynecological laparoscopic surgery can affect cerebral oxygenation through the change of cerebral blood flow. The aim of this study was to evaluate the effect of pneumoperitoneum in a 20degrees Trendelenburg position on regional cerebral oxygen saturation (rSO2). METHODS: Thirty-three female patients of American Society of Anesthesiologists I and II physical status who were undergoing gynecological laparoscopic surgery were enrolled. The rSO2 was monitored with near-infrared spectroscopy (INVOS 5100, Somanetics, Troy, USA). The rSO2, the rate of change in the rSO2, the mean arterial pressure (MAP), heart rate (HR), arterial partial pressure of CO2 (PaCO2) and O2 (PaO2) and end-tidal CO2 (ETCO2) were measured at the following times: immediately before the pneumoperitoneum and when placing the patient in the Trendelenburg position (T0), 5, 10, 15 and 20 min after pneumoperitoneum and position change (T1, T2, T3 and T4). RESULTS: Both the right and the left rSO2 increased significantly during pneumoperitoneum in a Trendelenburg position compared with the value at T0 (from T1 to T4) (P < 0.01). The MAP and PaCO2 also increased significantly (P < 0.01). CONCLUSIONS: During the gynecologiccal laproscopioc surgery, cerebral oxygenation, as assessed by rSO2, increased even though the Trendelenburg position and pneumoperitoneum could increase MAP, intracranial pressure and PaCO2, which is considered to be maintained by cerebral autoregulation.

Preoxygenation in pediatric patients

BACKGROUND: Preoxygenation with tidal volume breathing for 3 min is a standard technique using 100% oxygen for prevention of hypoxia during the induction of general anesthesia. The measurement of end tidal oxygen concentration is useful in preoxygenation monitoring. The aim of the study was to determine the effects of preoxygenation in pediatric patients during 3 min with tidal volume breathing. METHODS: Sixty patients who were scheduled for general surgery were divided into 0-6 yr old children (Group I, n = 20), 7-15 yr old children (Group II, n = 20) and adults (Group III, n = 20). Patients with an inflatable mask connected to an anesthesia machine breathed 100% oxygen spontaneously for 3 min with tidal volume in all three groups. End tidal oxygen concentration, end tidal carbon dioxide concentration and respiratory rate were measured simultaneously for 3 min. RESULTS: Group I and II showed significantly higher end tidal oxygen concentrations than Group III from 10 sec to 160 sec with 3 min tidal volume breathing (P < 0.05). The mean time required for end tidal oxygen concentration of 90% was 85.5 +/- 18.5 sec for Group I, 101.5 +/- 21.5 sec for Group II and 148.0 +/- 24.0 sec for Group III. Therefore, Group I and II showed a significantly shorter time than Group III (P < 0.05). CONCLUSIONS: Pediatric patients showed a significantly shorter time to obtain the required preoxygenation.

Clinical comparisons of 0.5% and 0.375% levobupivacaine for ultrasound-guided axillary brachial plexus block with nerve stimulation / 대한마취과학회지

BACKGROUND: In an axillary brachial plexus block (ABPB), where relatively large doses of local anesthetics are administered, levobupivacaine is preferred due to a greater margin of safety. However, the efficacy of levobupivacaine in ABPB has not been studied much. We performed a prospective, double-blinded study to compare the clinical effect of 0.375% levobupivacaine with 0.5% levobupivacaine for ultrasound (US)-guided ABPB with nerve stimulation. METHODS: Forty patients undergoing elective upper limb surgery were randomized into two groups: Group I (0.375% levobupivacaine) and Group II (0.5% levobupivacaine). All four main terminal nerves of the brachial plexus were blocked separately with 7 ml of levobupivacaine using US guidance with nerve stimulation according to study group. A blinded observer recorded the onset time for sensory and motor block, elapsed time to be ready for surgery, recovery time for sensory and motor block, quality of anesthesia, patient satisfaction and complications. RESULTS: There were no significant differences in the time to find nerve locations, time to perform block and number of skin punctures between groups. Insufficient block was reported in one patient of Group I, but no failed block was reported in either group. There were no differences in the onset time for sensory and motor block, elapsed time to be ready for surgery, patient satisfaction and complications. CONCLUSIONS: 0.375% levobupivacaine produced adequate anesthesia for ABPB using US guidance with nerve stimulation, without any clinically significant differences compared to 0.5% levobupivacaine.

Impending compartment syndrome of the forearm and hand after a pressurized infusion in a patient under general anesthesia: A case report / 대한마취과학회지

A 74-year-old woman underwent posterior lumbar decompressive fusion at L4-5 for treating spondylolisthesis, with the patient under general anesthesia and she was in the prone position. Following attempts to transfuse blood using a pressurized bag, the intravenous infusion site of the left hand along with the noninvasive blood pressure cuff was changed. Swelling and several bullae on the left forearm and hand were visible. Removal of intravenous catheter, hyaluronidase injection, wet dressing were subsequently performed. In postanesthesia recovery unit, the patient did not complain of pain, and the radial pulse and oxygen saturation of the left appeared normal. Three days after the incident, the edema on the patient's forearm and hand subsided, and the patient was discharged without any complications two weeks afterwards. Impending compartment syndrome should be given close attention, and particularly when performing pressurized infusion in patients who are unable to express pain because they are under general anesthesia.

The effects of hip abduction with external rotation and reverse Trendelenburg position on the size of the femoral vein; ultrasonographic investigation / 대한마취과학회지

BACKGROUND: Femoral vein (FV) catheterization is required for critically ill patients, patients with difficult peripheral intravenous access, and patients undergoing major surgery. The purpose of this study was to evaluate the effects of hip abduction with external rotation (frog-leg position), and the frog-leg position during the reverse Trendelenburg position on diameter, cross-sectional area (CSA), exposed width and ratio of the FV using ultrasound investigation. METHODS: Ultrasonographic FV images of 50 adult subjects were obtained: 1) in the neutral position (N position); 2) in the frog-leg position (F position); 3) in the F position during the reverse Trendelenburg position (FRT position). Diameter, CSA, and exposed width of the FV were measured. Exposed ratio of the FV was calculated. RESULTS: The F and FRT positions increased diameter, CSA and exposed width of the FV significantly compared with the N position. However, the F and FRT positions had no significant effect on exposed ratio of the FV compared with the N position. The FRT position was more effective than the F position in increasing FV size. CONCLUSIONS: The F and FRT positions can be used to increase FV size during catheterization. These positions may increase success rate and reduce complication rate and, therefore, can be useful for patients with difficult central venous access or at high-risk of catheter-related complication.