Experience with wound care in a case with ECMO cannulation using a self-made vacuum-sealing drainage device with constant-temperature flushing.

Background：This study reports experience of wound care at the site of cannulation in the case of a patient with dilated cardiomyopathy (DCM) weaned from extracorporeal membrane oxygenation (ECMO). PURPOSE: To describe the use of a self-made vacuum-sealing drainage device with constant-temperature flushing to manage wound exudates in the cannulation site, aiming to create an environment conducive to wound healing. MATERIALS AND METHODS: Exudates from the wound were processed using the vacuum-sealing drainage technique combined with constant-temperature flushing. Anti-infective agents were systemically administered to control infection and promote wound healing. Additionally, the patient's nutritional status, pain management, psychological well-being, and rehabilitation were assessed and managed as part of the comprehensive care approach. RESULTS: The wound exhibited gradual healing under this multifaceted care strategy. After 48 days of treatment, the patient demonstrated stable disease conditions and achieved wound closure. The patient was subsequently transferred to a general ward for further care. CONCLUSION: The use of a self-made vacuum-sealing drainage device with constant-temperature flushing, along with comprehensive patient management, proved effective in wound care for a critically ill patient with ECMO cannulation. This approach fosters an optimal environment for wound healing and contributes to patient recovery and stability.

A Multicenter, Single-Arm, Objective Performance Criteria-Controlled Clinical Study of the Safety and Efficacy of the Double-Lumen Eustachian Tube Balloon Catheter.

BACKGROUND: To prospectively evaluate the technical efficacy and safety of the double-lumen eustachian tube (ET) balloon catheter in patients with ET dysfunction. METHODS: Patients who were diagnosed with ET dysfunction and needed balloon eustachian tuboplasty (BET) were prospectively enrolled. A double-lumen ET balloon catheter was used to dilate the ET and inject medicine. Efficacy results were assessed by the injection channel patency (ICP) rate, the injection reached the expected site (IRES) rate, and the improvement in eustachian tube function was evaluated by the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7) score. Safety results were assessed in terms of adverse events and device defects. RESULTS: BET was successfully attempted in 87 patients from April 2022 to August 2022 at two academic medical centers in China (01, 02). The ICP rate was 100%, and the IRES rate was 88.51%. The overall ETDQ-7 score was significantly reduced ( p < 0.001) postsurgically at both centers. There were no major complications or device defects. CONCLUSION: The double-lumen ET balloon catheter is technically effective and safe for the treatment of ET dysfunction.

Direct Apical Cannulation With Protek Duo Rapid Deployment Cannula via Mini Thoracotomy for Ambulatory Venoarterial-Extracorporeal Membrane Oxygenation.

National trends show rapid increases in the use of mechanical circulatory support devices (MCSD) over the last 20 years. While current literature has not proven a mortality benefit in cardiogenic shock as a complication of acute myocardial infarction (AMI-CS) with percutaneous MCSD, these devices are vital to maximizing cardiopulmonary parameters for definitive therapy. To minimize complications, many different techniques have been described including a novel off-pump direct apical cannulation for venoarterial-extracorporeal membrane oxygenation (VA-ECMO). This technique allows early ambulation and avoids peripheral artery access complications but has only been described in small case series. Our case series represents the largest summary of patients (50) using this technique and contains the only comparison data to date. Fifty-four percentage of our patients were Society for Cardiovascular Angiography and Interventions (SCAI) stage D and 22% were arrested before cannulation. We achieved flows on average >5 L/min and most patients required biventricular drainage (86%) and an oxygenator (92%). Thirty day survival was 56% and most survivors were bridged to heart transplant (30%). Our most common complication was bleeding (16%). This technique showed significant improvement in ejection fraction (EF), cardiac output/index (CO/CI), and pulmonary artery pressures. This case series demonstrates the safety and efficacy of this novel technique for central cannulation in cardiogenic shock at large scale within a single institution.

Early vs. delayed amniotomy in individuals undergoing pre-induction cervical ripening with transcervical Foley balloon: a meta-analysis.

OBJECTIVES: To systematically review randomized controlled trials (RCTs) and perform a meta-analysis comparing early amniotomy with delayed amniotomy in individuals undergoing pre-induction cervical ripening by Foley balloon. The primary outcome was the rate of cesarean delivery. Understanding the impact of the timing of amniotomy on the rate of cesarean delivery is crucial for obstetricians and healthcare providers when making decisions about the management of labor induction. DATA SOURCES: Data were sourced from electronic databases, including PubMed, OVID, Cochrane Library, Web of Science, and ClinicalTrials.gov through February 2024. The review adhered to Preferred Reporting Item for Systematic Reviews guidelines and registered with PROSPERO (ID CRD42023454520). STUDY ELIGIBILITY CRITERIA: Inclusion criteria comprised RCTs comparing early amniotomy with delayed amniotomy in individuals undergoing cervical ripening by Foley balloon. Early amniotomy was defined as amniotomy soon after cervical ripening. Delayed amniotomy was defined as withholding amniotomy until after the onset of the active phase of labor, until at least 4 hours from either initiation of oxytocin or Foley balloon removal/expulsion, or until achieving >4 cm of dilation. Participants included nulliparous or multiparous individuals with singleton pregnancies undergoing labor induction at 37 weeks or later. STUDY APPRAISAL AND SYNTHESIS: A systematic literature search was conducted using defined search terms including "early amniotomy," "delayed amniotomy," "induction of labor," "cervical ripening," and "Foley balloon," and "Foley catheter." The quality of the included trials was assessed using the Cochrane Risk of Bias Tool for randomized controlled trials. The primary outcome was cesarean delivery. Secondary outcomes included outcomes related to labor duration and neonatal outcomes. Pooled relative risks (RR) and weighted mean differences (WMD) with 95% confidence intervals were calculated. RESULTS: Five trials involving 849 participants undergoing induction and cervical ripening by Foley balloon were included. The rate of cesarean delivery did not differ between individuals randomly assigned to the early amniotomy group compared with those assigned to the delayed amniotomy group (22.9% vs. 23.3%; RR 1.00; 95% CI 0.65-1.55). Early amniotomy compared to delayed amniotomy was associated with a higher proportion of delivery within 24 hours (79.9% vs. 67.1%; RR 1.19; 95% CI 1.04-1.36). Early amniotomy compared with delayed amniotomy was associated with a shorter interval from oxytocin to delivery (WMD -1.5 hours; 95% CI -2.1 to -0.8), from Foley expulsion to vaginal delivery (WMD -2.5 hours; 95% CI -4.8 to -0.1), and from the start of oxytocin to vaginal delivery (WMD -1.8 hours; 95% CI -3.2 to -0.4). Other outcomes were not significantly different. CONCLUSION: Early amniotomy following cervical ripening by Foley balloon in individuals with singleton pregnancies did not impact rates of cesarean delivery compared with delayed amniotomy but led to shorter duration for various labor progress outcomes.

Papaverine prior to catheter balloon insertion for labor induction: a randomized controlled trial.

BACKGROUND: Catheter balloon insertion is a common method for cervical ripening and labor induction. Papaverine and its derivatives are musculotropic antispasmodic drugs that directly induce smooth muscle relaxation. Used during childbirth, these drugs have been suggested to shorten the duration of labor. OBJECTIVE: This study aimed to evaluate the effect of administering papaverine before catheter balloon insertion on changes in Bishop scores and on the labor induction-to-delivery interval. STUDY DESIGN: This randomized, double-blinded, placebo-controlled trial was conducted in a single tertiary university-affiliated hospital. Participants were admitted at term for labor induction with an initial Bishop score of ≤6. Participants were randomized to receive 80 mg intravenous papaverine or 0.9% normal saline solution within 30 minutes of Foley catheter balloon insertion. The co-primary outcomes were the difference in Bishop score from before catheter balloon insertion to after removal and the labor induction-to-delivery interval. The secondary outcomes included maternal pain and satisfaction scores, delivery within 24 hours, and neonatal outcomes. Both intention-to-treat and per-protocol analyses were performed. RESULTS: Overall, 110 women were enrolled. In the intention-to-treat analysis, the median difference in Bishop score was greater in the papaverine group than in the placebo group (5 [interquartile range, 1-11] vs 4 [interquartile range, 0-7], respectively; P=.025), and the median catheter balloon insertion-to-delivery interval was shorter in the papaverine group than in the placebo group (21 hours [interquartile range, 6-95] vs 26 hours [interquartile range, 3-108], respectively; P=.031). A higher proportion of women delivered within 24-hours in the papaverine group than in the placebo group (65.5% vs 41.8%, respectively; P=.012). Pain and satisfaction scores, delivery, and neonatal outcomes were similar between the groups. Similar results were found in the per-protocol analysis. CONCLUSION: Papaverine administration before Foley catheter balloon insertion for cervical ripening resulted in improved Bishop scores and shorter catheter balloon insertion-to-delivery intervals.

Development of an adjustable patient-specific rigid guide to improve the accuracy of external ventricular catheter placement.

OBJECTIVE: The most common method for external ventricular drain (EVD) placement is the freehand approach, which has reported inaccuracy rates of 12.3%-44.9%, especially in the case of altered ventricular anatomy. Current assistive devices require added time or equipment or do not account for shifted ventricles. To improve the accuracy of emergent EVD placement in the setting of altered ventricular anatomy, the authors designed a patient-specific EVD (PS-EVD) guide. METHODS: The PS-EVD guide has a tripod base and a series of differently angled inserts that lock in place at multiple rotational positions, allowing for numerous insertion angles. For testing, the authors designed a 3D-printed phantom skull with a gelatin brain analog containing ventricles simulating normal and altered ventricular anatomy. Low-resolution CT scans of the phantom were used to calculate the insertion angle in relation to the standard perpendicular entry. The corresponding insert at the correct rotational position within the base unit was positioned over the entry point on the phantom, and the catheter was inserted. Accuracy was evaluated with repeat CT scans. RESULTS: With normal ventricular anatomy, as well as abnormally shifted ventricles, proper use of the PS-EVD guide led to accurate catheter insertion into the ventricle in trials, as confirmed on coronal and sagittal CT images, including cases in which a perpendicular trajectory, such as with the Ghajar guide, was insufficient. CONCLUSIONS: The PS-EVD guide allows consistent and accurate EVD placement in phantom skulls with both normal and altered ventricular anatomy. Further trials comparing this device to the freehand approach are required.

Balloon dacryoplasty: A boon for dacryologists in managing persistent congenital nasolacrimal duct obstructions.

PURPOSE: To study the outcomes of balloon dacryoplasty (BD) or (BDCP) in children with persistent congenital nasolacrimal duct obstruction (pCNLDO) by using new and reused balloon catheters. METHODS: Our retrospective analysis focused on managing pCNLDO by using the BD or BDCP technique. The study included children aged >1 year to <12 years who underwent single or multiple probings before. Our specific lacrimal workup included a detailed history and examination, as published earlier. We used conventional, straight, 2 mm × 13 mm/3 mm × 15 mm lacrimal balloons (FCI, Ophthacath). We have described a technique to use the same catheter for three BD procedures (1 new + 2 reuse). The outcomes were categorized as complete success, partial success, and failure. The minimum follow-up of each child was 6 months. RESULTS: We analyzed 64 children (89 eyes) with a mean age of 58 months (15-132 months). All children (100%) had epiphora with discharge and positive FDDT. All children underwent BD under general anesthesia - new balloons in 59 eyes and reused balloons in 30 eyes. The balloons were plasma sterilized akin to vitrectomy cutters and tubings of phaco machines. We noted three leaks from reused balloons (2 from the balloon tip and 1 from the plastic hub). At a mean follow-up of 14.5 months, complete success was noted in 77 eyes (86.5%) (52 new and 25 reuse), while 8 eyes had partial success (8.9%) (4 new and 4 reuse). Failure of BD was noted in four eyes (4.5%) (3 new and 1 reuse). None had significant complications with new or reused balloons. CONCLUSION: BD or BDCP is a quick, safe, easy, and effective procedure that resolves pCNLDO symptoms satisfactorily. Carefully reusing a conventional balloon catheter is possible with comparable efficacy and no additional complications in pCNLDO.

Transpancreatic Sphincterotomy After Double Guidewire Technique Was Noninferior to Primary Transpancreatic Sphincterotomy in Difficult Biliary Cannulation.

BACKGROUND: When unintentional pancreatic duct access occurs during difficult biliary cannulation, the double guidewire (DGW) or transpancreatic sphincterotomy (TPS) may be utilized. DGW can be easily switched to TPS due to the existing guidewire in the pancreatic duct. However, the efficacy of TPS after DGW, named sequential DGW-TPS technique, versus primary TPS has not been assessed. AIMS: Our aim was to compare the benefits and adverse events of sequential DGW-TPS technique and primary TPS. METHODS: We performed a comparative retrospective cohort study that enrolled a total of 117 patients with native papillae. The patients were divided into one of 2 groups according to the primary bile duct access technique (sequential DGW-TPS or primary TPS), both with pancreatic stenting. RESULTS: Between November 2017 and May 2023, a total of 84 patients were grouped into sequential DGW-TPS and 33 into primary TPS. The overall post-ERCP pancreatitis (PEP) rate was 4.3% in the entire cohort, with no statistical differences were observed between the groups in terms of PEP rates (P = 0.927), PEP severity (P = 1.000), first biliary cannulation success (P = 0.621), overall cannulation success (P = 1.000), hyperamylasemia incidence (P = 0.241), elevated amylase levels (P = 0.881), and postoperative hospital stay (P = 0.185). Furthermore, these results remained consistent in multivariable regression analysis. CONCLUSIONS: The sequential DGW-TPS technique showed a comparable safety and biliary cannulation success rate to primary TPS in difficult biliary cannulation. Given the potential long-term complications associated with TPS, DGW should be first if inadvertent pancreatic access occurs, with TPS serving as second only if DGW fails.

Cannulation of pancreaticojejunostomy anastomosis with a novel controllable catheter.

Anastomotic stenosis of hepaticojejunostomy and pancreaticojejunostomy are common adverse events after pancreaticoduodenectomy. Kuraoka and colleagues describe their method of cannulating the bile and pancreatic ducts using a novel catheter with a controllable tip, which is useful when it is difficult to align the axis of the forceps port and the anastomosis.

Successful cholangioscopy-guided cannulation using a novel slim cholangioscope.

Selective biliary cannulation is a difficult step in endoscopic retrograde cholangiopancreatography. In this case video, Tanisaka and colleagues report a successful cholangioscopy-guided cannulation achieved using a novel slim cholangioscope with a 2.3-mm scope tip. Cholangioscopy-guided cannulation using this cholangioscope could be a good option in cases of difficult biliary cannulation.

Loss-of-Resistance Versus Dynamic Pressure-Sensing Technology for Successful Placement of Thoracic Epidural Catheters: A Randomized Clinical Trial.

BACKGROUND: The traditional loss-of-resistance (LOR) technique for thoracic epidural catheter placement can be associated with a high primary failure rate. In this study, we compared the traditional LOR technique and dynamic pressure-sensing (DPS) technology for primary success rate and secondary outcomes pertinent to identifying the thoracic epidural space. METHODS: This pragmatic, randomized, patient- and assessor-blinded superiority trial enrolled patients ages 18 to 75 years, scheduled for major thoracic or abdominal surgeries at a tertiary care teaching hospital. Anesthesiology trainees (residents and fellows) placed thoracic epidural catheters under faculty supervision and rescue. The primary outcome was the success rate of thoracic epidural catheter placement, evaluated by the loss of cold sensation in the thoracic dermatomes 20 minutes after injecting the epidural test dose. Secondary outcomes included procedural time, ease of catheter placement, the presence of a positive falling meniscus sign, early hemodynamic changes, and unintended dural punctures. Additionally, we explored outcomes that included number of attempts, needle depth to epidural space, need for faculty to rescue the procedure from the trainee, patient-rated procedural discomfort, pain at the epidural insertion site, postoperative pain scores, and opioid consumption over 48 hours. RESULTS: Between March 2019 and June 2020, 133 patients were enrolled; 117 were included in the final analysis (n = 57 for the LOR group; n = 60 for the DPS group). The primary success rate of epidural catheter placement was 91.2% (52 of 57) in the LOR group and 96.7% (58 of 60) in the DPS group (95% confidence interval [CI] of difference in proportions: -0.054 [-0.14 to 0.03]; P = .264). No difference was observed in procedural time between the 2 groups (median interquartile range [IQR] in minutes: LOR 5.0 [7.0], DPS 5.5 [7.0]; P = .982). The number of patients with epidural analgesia onset at 10 minutes was 49.1% (28 of 57) in the LOR group compared to 31.7% (19 of 60) in the DPS group ( P = .062). There were 2 cases of unintended dural punctures in each group. Other secondary or exploratory outcomes were not significantly different between the groups. CONCLUSIONS: Our trial did not establish the superiority of the DPS technique over the traditional LOR method for identifying the thoracic epidural space ( Clinicaltrials.gov identifier: NCT03826186).

Effect of endometrial scratching on unassisted conception for unexplained infertility: a randomized controlled trial.

OBJECTIVE: To investigate whether endometrial scratching increases the chance of live birth in women with unexplained infertility attempting to conceive without assisted reproductive technology. DESIGN: Randomized, placebo-controlled, participant-blind, multicenter international trial. SETTING: Fertility clinics. PATIENT(S): Women with a diagnosis of unexplained infertility trying to conceive without assistance. INTERVENTION(S): Participants were randomly assigned to receive an endometrial biopsy or a placebo procedure (placement of a biopsy catheter in the posterior fornix, without inserting it into the external cervical os). Both groups performed regular unprotected intercourse with the intention of conceiving over three consecutive study cycles. MAIN OUTCOME MEASURE(S): The primary outcome was live birth. RESULT(S): A total of 220 women underwent randomization. The live birth rate was 9% (10 of 113 women) in the endometrial-scratch group and 7% (7 of 107 women) in the control group (adjusted OR, 1.39; 95% CI, 0.50-4.03). There were no differences between the groups in the secondary outcomes of clinical pregnancy, viable pregnancy, ongoing pregnancy, and miscarriage. Endometrial scratching was associated with a higher pain score on a 10-point scale (adjusted mean difference, 3.07; 95% CI, 2.53-3.60). CONCLUSION(S): This trial did not find evidence that endometrial scratching improves the live birth rate in women with unexplained infertility trying to conceive without assistance. CLINICAL TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry ACTRN12614000656639.

Insufficient procedural anticoagulation during leadless pacing led to catheter-related thrombosis in a hemodialysis patient.

BACKGROUND: Leadless pacemaker was a promising innovation than traditional transvenous pacemaker, the procedural complications were prone to be bleeding-related. However, very few reports also concerned about the thrombus formation during the procedure. CASE PRESENTATION: A hemodialysis patient with diabetic gangrene of right foot suffered from catheter-related thrombosis during leadless pacing, resulting in failure of recapture the pacemaker. A low activated clotting time (ACT) level of 104 s confirmed the insufficiency of anticoagulation. Finally, the whole delivery catheter had to be removed from the delivery sheath, another new pacemaker system was applied and successfully implanted after adjusting the ACT level to 248 s. CONCLUSION: Catheter-related thrombosis could be a large obstacle for leadless pacemaker implantation. In addition to routine anticoagulation, ACT monitoring might be necessary during the procedure.

Hydrogel-coated needles prevent puncture site bleeding in arteriovenous fistula and arteriovenous grafts in rats.

INTRODUCTION: Imperfect hemostasis after arteriovenous fistula (AVF) and arteriovenous graft (AVG) cannulation can cause a hematoma or pseudoaneurysm and leads to poor satisfaction. We hypothesized that a hydrogel-coated needle would effectively and rapidly stop bleeding after vascular cannulation in a rat AVF and AVG model. METHOD: A hydrogel comprised of sodium alginate (SA), hyaluronic acid (HA), and calcium carbonate was coated onto the surface of suture needles using a rotating system. The needles were observed using scanning electron microscopy (SEM) and immunofluorescence. Rat AVF with or without renal failure and AVG were punctured using bare and hydrogel-coated needles. The tissues were examined by histology. RESULT: The hydrogel was successfully coated onto the surface of 30 G needles and confirmed by SEM. Hydrogel-coated needles rapidly stopped bleeding after AVF and AVG cannulation in rat. CONCLUSION: In this preliminary animal research, hydrogel-coated needles can stop AVF and AVG puncture-site bleeding; but additional clinical studies are needed to justify whether it is still effective in clinical.

Falloposcopic tuboplasty: an easy, quick, and safe technique.

OBJECTIVE: To describe our simplified technique for falloposcopic tuboplasty (FT) and demonstrate its principle and results. DESIGN: A step-by-step description of the technique and demonstration of its principle using a clay model. SETTING: Private infertility clinics in Osaka and Tokyo operated by 10 physicians. PATIENT(S): A total of 431 infertile women with a diagnosis of unilateral or bilateral proximal tubal occlusion (6 cm from the uterotubal ostia), between October 2013 and February 2019 were included. These patients underwent routine work-ups for infertility, including a semen analysis, hysterosalpingography, antimüllerian hormone, basal luteinizing hormone/follicle-stimulating hormone and prolactin concentrations during menstruation, postcoital test in the periovulatory period, and estradiol and progesterone concentrations in the middle of the luteal phase. Physicians performed hysterosalpingography to evaluate tubal patency and uterine shape. Saline infusion sonography was not conducted because it does not accurately identify regions of tubal occlusion and/or stenosis. INTERVENTION(S): The principle of our simplified technique for FT is that a hole is located at the side of the FT catheter tip. Therefore, the balloon and fiberscope move away from the catheter line (Fig. 1). The uterotubal ostium is located at the tip-end of the triangle of the uterine cavity. When a balloon is inserted while visualizing the uterotubal ostium at the nearest position to the ostium, the balloon hits the uterine wall. When a balloon is inserted 5-10 mm from the uterotubal ostium without visualization, the balloon may be easily placed in the ostium through its convex angle, allowing it to slide into the uterine wall (Figs. 2 and 3). Step 1: Confirm anteflexion or retroflexion of the uterus by ultrasound. Step 2: Confirm the direction of the uterotubal ostia by hysteroscopy. Step 3: Adjust the angle of the FT catheter according to steps 1 and 2, insert the catheter into the end of the uterus, pull it back 5-10 mm (without visualizing the uterotubal ostia), and then fix it to the forceps. Catheter placement away from the tubal ostium is confirmed by the residual length of the moving part of the catheter. An attending instructor should ask the operator about the feeling of rigidity when the catheter does not advance and then suggest whether to proceed or stop. In the latter case, the catheter is not moved, saline is infused for 1 minute for lubrication, the balloon is pulled back using the fiberscope to remove the bunching of the balloon, and balloon pressure is changed as follows: 6→8→6→10→6 mmHg. Our institutional review board stated that approval was not required because the video describes the technique of our routine procedure. MAIN OUTCOME MEASURE(S): A description of the FT technique using a clay model and a demonstration of its application in our clinic. RESULT(S): The average operative time was 15.4 minutes, and the clinical pregnancy rate was 24.4% (natural conception and intrauterine insemination without in vitro fertilization). No significant differences were observed in the operative time or pregnancy rate among physicians. Approximately 17 FT procedures may be performed using one fiberscope. CONCLUSION(S): Our simplified technique, which was described and demonstrated in this video article, is a feasible and practical approach for performing FT. It provides excellent cost performance by saving fiberscopes. The most important point is "Introduce the balloon and fiberscope 5-10 mm away from the uterotubal ostia without visualizing it." To facilitate learning this technique, we recommend watching the video and then practicing FT without searching for the uterotubal ostia. Physicians master FT without any assistance by an attending instructor in ≤3 attempts.

Relationship Between the Loaded Pressure and Flow Rate of Packed Red Blood Cells and Various Infusion Solutions in Normal Infusion Lines and Catheters.

BACKGROUND: We investigated the relationship between the loaded pressure and flow rate in various catheters and the entire infusion line including the catheters, in several infusion solutions and packed red blood cells. METHODS: We connected the infusion line and catheter to the infusion solution and used an outer pressure bag or a compressor to pressurize the infusion solution bag to a pressure within the clinical (up to 450 mm Hg) or higher range (up to 1050 mm Hg). We approximated the relationship between the loaded pressure and flow rate in the entire infusion line including the catheter, versus the catheter alone, as a power function and compared the power numbers. RESULTS: In the clinical pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.76, 0.82, 0.81, and 0.86, respectively, while those for the catheter alone were 0.67, 0.63, 0.56, and 0.44, respectively. In the higher pressure range of normal saline, the power numbers of the entire infusion line for the 24-, 22-, 20-, and 18-gauge catheters were 0.68, 0.70, 0.71, and 0.73, respectively, while those for the catheter alone were 0.62, 0.61, 0.59, and 0.58, respectively. As the power number of the entire infusion line was closer to 1.00 than the values of the catheter, the relation between the loaded pressure and the flow rate was more linear in the entire infusion line than that in the catheter. Similar results were obtained using packed red blood cells and 40% glycerin mixture in normal saline. CONCLUSIONS: Regardless of the type of infusion solution or transfusion, the pressure-flow relationship in the catheter was nonlinear and not directly proportional. However, within the clinical pressure range (up to 450 mm Hg), the relationship between the flow rate and pressure in the entire infusion line was almost linear and proportional.