Infusion Flow Research Articles

A holstein cow–calf model for the transfer of ciprofloxacin through milk after a long‐term intravenous infusion

This study is part of an ongoing effort to develop animal models that provide milk and sufficient infant (offspring) plasma samples to fully describe a drug's pharmacokinetics to quantitate the risk to the nursing infant. Ciprofloxacin was administered to six healthy Holstein cows as a constant rate intravenous infusion (flow rate was weight adjusted) to achieve a steady-state concentration of approximately 300 ng/mL for 7 days. Plasma and milk samples were collected from the cow at regular intervals over the course of the 7 days. The plasma and milk samples were analyzed for ciprofloxacin by high-performance liquid chromatography. The milk was fed to calves, and calf plasma samples were analyzed to study the lactational transfer of ciprofloxacin from dam to nursing neonate. Remarkably, concentrations of ciprofloxacin in milk were 45 times higher than plasma drug concentrations in the dam. Approximately 6% of the administered dose was transferred to the milk, resulting in an average oral dose of 0.5 mg/kg to the calves with every feeding. The drug did not accumulate in the calves, and plasma concentrations were between one-tenth and one-fifth the plasma concentrations of the dam.

Minimization of the Preanalytical Error in Pharmacokinetic Analyses and Therapeutic Drug Monitoring

The conduct of multicenter pharmacokinetic (PK) analyses for long-established drugs entails specific problems, because samples have to be obtained within daily clinical practice. Practices for intravenous (IV) drug administration vary between hospitals, including the use of different infusion devices, the use of infusion line systems with different line volumes, and different priming and rinsing procedures. Variables of IV drug administration that could influence concentration data obtained in PK analyses were evaluated. Kinetics of drug delivery during initiation and cessation of IV infusions were simulated in vitro for a drop-counter and a syringe-driven infusion system at different flow rates. Furthermore, the percentages of the target drug dosage remaining in the infusion line after different rinsing periods were investigated in vitro and in clinical practice. Varying times required for the drug to migrate from the bag/syringe to the cannula and to reach a steady-state drug administration rate were observed. Time to steady state ranged from almost immediate to 48 minutes depending on the infusion system and flow rate. The longest times were seen for the drop-counter system at low flow rates and were associated with large drug concentration gradients in the infusion line, which makes it difficult to accurately determine start and end of the infusion. For most systems, when rinsing at the end of infusion was performed with once the volume of the infusion line, <5% of the total drug dosage was discarded. Larger variability was seen for slow infusion rates and small infusion volumes. The choice of the infusion apparatus, standardized infusion systems, and standardized operating procedures for drug administration are important when performing postmarketing PK analyses in multicentric studies.

Polymer-coated cannulas for the reduction of backflow during intraparenchymal infusions

Infusate backflow or leak-back along the cannula track can occur during intraparenchymal infusions resulting in non-specific targeting of therapeutic agents. The occurrence of backflow depends on several variables including cannula radius, infusate flow rate, and tip location. In this study, polymer coatings that swell in situ were developed and tested with in vitro hydrogel experiments for backflow reduction. Coatings were applied to the external cannula surface in a dual layer arrangement with a poly(vinyl alcohol) outer layer atop an inner poly(ethylene oxide) and alginate layer. Once these coated cannulas were inserted and allotted an 8-10 min waiting period for hydration, backflow during infusions of 4.0 μl of a macromolecular tracer (Evans Blue labeled albumin) was reduced significantly under flow rates of 0.3-0.6 μl/min, allowing for more effective distribution within targeted regions. Polymer coating thicknesses before and after hydrations were 0.035 and 0.370 mm, respectively. Also, backflow data was fit to a model to estimate the effective local compressive stress caused by the hydrated polymers. After withdrawal of the cannula from the insertion site, the hydrated polymer coatings remained within the cavity left in the hydrogel tissue phantom and formed a seal at the infusion site that prevented further backflow during needle withdrawal. Ex vivo infusions in excised porcine brain tissues also showed significant backflow reduction while also demonstrating the ability to leave a polymer seal in the tissue cavity after cannula removal. Thus, application of these polymers as needle or cannula coatings offers a potentially simple method to improve targeting for local drug delivery.

Increased right ventricular output and central pulmonary reservoir function support rise in pulmonary blood flow during adenosine infusion in the ovine fetus

Although adenosine markedly increases fetal pulmonary blood flow, the specific changes in pulmonary trunk (PT), ductus arteriosus (DA), and conduit pulmonary artery (PA) flow interactions that support this increased flow are unknown. To address this issue, seven anesthetized late-gestation fetal sheep were instrumented with PT, DA, and left PA micromanometer catheters and transit-time flow probes. Blood flow profile and wave intensity analyses were performed at baseline and after adenosine infusion to increase PA flow approximately fivefold. With adenosine infusion, DA mean and phasic flows were unchanged, but increases in mean PT (500 ± 256 ml/min, P = 0.002) and the combined left and right PA flow (479 ± 181 ml/min, P < 0.001) were similar (P > 0.7) and related to a larger flow-increasing forward-running compression wave arising from right ventricular (RV) impulsive contraction. Moreover, while the increased PT flow was confined to systole, the rise in PA flow spanned systole (316 ml/min) and diastole (163 ml/min). This elevated PA diastolic flow was accompanied by a 170% greater discharge from a PT and main PA reservoir filled in systole (P < 0.001), but loss of retrograde blood discharge from a conduit PA reservoir that was evident at baseline. These data suggest that 1) an increase in fetal pulmonary blood flow produced by adenosine infusion is primarily supported by a higher PT blood flow (i.e., RV output); 2) about two-thirds of this increased RV output passes into the pulmonary circulation during systole; and 3) the remainder is transiently stored in a central PT and main PA systolic reservoir, from where it discharges into the lungs in diastole.

Influence of Needle Insertion Speed on Backflow for Convection-Enhanced Delivery

Fluid flow back along the outer surface of a needle (backflow) can be a significant problem during the direct infusion of drugs into brain tissues for procedures such as convection-enhanced delivery (CED). This study evaluates the effects of needle insertion speed (0.2 and 1.8 mm/s) as well as needle diameter and flow rate on the extent of backflow and local damage to surrounding tissues. Infusion experiments were conducted on a transparent tissue phantom, 0.6% (w/v) agarose hydrogel, to visualize backflow. Needle insertion experiments were also performed to evaluate local damage at the needle tip and to back out the prestress in the surrounding media for speed conditions where localized damage was not excessive. Prestress values were then used in an analytical model of backflow. At the higher insertion speed (1.8 mm/s), local insertion damage was found to be reduced and backflow was decreased. The compressive prestress at the needle-tissue interface was estimated to be approximately constant (0.812 kPa), and backflow distances were similar regardless of needle gauge (22, 26, and 32 gauge). The analytical model underestimated backflow distances at low infusion flow rates and overestimated backflow at higher flow rates. At the lower insertion speed (0.2 mm/s), significant backflow was measured. This corresponded to an observed accumulation of material at the needle tip which produced a gap between the needle and the surrounding media. Local tissue damage was also evaluated in excised rat brain tissues, and insertion tests show similar rate-dependent accumulation of tissue at the needle tip at the lower insertion speed. These results indicate that local tissue damage and backflow may be avoided by using an appropriate insertion speed.

Idiopathic acute myocardial infarction in a young patient with noncompaction cardiomyopathy

Isolated left ventricular noncompaction (LVNC) is a rare hereditary cardiomyopathy characterized by prominent intraventricular trabeculations separated by deep intertrabecular recessus. While cardiac ischemia due to microvascular dysfunction is common in these patients, ST-segment elevation myocardial infarction (STEMI) is rare and usually seen as a consequence of coincidental coronary artery disease. We report the case of a 20 year-old male patient admitted to our emergency department with a complaint of squeezing chest pain who was subsequently diagnosed with STEMI according to electrocardiographic findings, although an emergent coronary angiogram demonstrated normal coronary arteries. Echocardiography revealed isolated LVNC, and the diagnosis was confirmed via magnetic resonance imaging. Repeat coronary catheterization with acetylcholine infusion and coronary flow reserve measurement failed to demonstrate vasospasm or microvascular dysfunction. As no apparent cause was found, this case was designated 'idiopathic' myocardial infarction. Coronary thromboembolism due to stagnation of blood in the left ventricular cavity remained as the most probable mechanism underlying myocardial infarction.

The Impact on Drug Mass Flow Rate of Interrupting and Resuming Carrier Fluid Flow

Stopping and resuming carrier fluid flow can lead to potentially dangerous transient disturbances in drug mass flow rate. We compared the impact of 2 infusion sets, one with very low dead-space volume and the other with greater dead-space volume, on the amount of drug delivered during stop-and-go carrier fluid flows. Two infusion sets, both with antireflux, connected to an angiocatheter and with dead-space volumes of 6.185 mL and 0.071 mL, respectively, were assessed. Two protocols were studied: carrier fluid flow of 90 mL/h associated with noradrenaline infused at 7 mL/h and carrier fluid flow of 350 mL/h with a noradrenaline infusion flow of 65 mL/h. During both protocols, the carrier fluid was stopped and resumed at the same rate 30 minutes later. Effluent noradrenaline concentration was measured using UV spectrophotometry. Flow change efficiency was calculated from the ratio of the area under the experimental mass flow rate curve to the area under the theoretical instantaneous mass flow rate curve. For both flow rate conditions, flow change efficiency was significantly different for the 2 infusion sets during the 10-minute period after stopping carrier fluid flow and the 10-minute period after restarting it. The major phenomena were sudden decreases in drug delivery after stopping carrier flow and sudden, temporary increases when it was resumed. The very low dead-space volume infusion set resulted in significant reduction in changes in drug delivery compared with the standard set, even at high flow rates. The use of a very low dead-space volume set attenuates disturbances in drug delivery caused by interrupting and resuming carrier fluid flow.

Air elimination capability in rapid infusion systems

Pressure infusion devices are used in clinical practice to apply large volumes of fluid over a short period of time. Although air infusion is a major complication, they have limited capability to detect and remove air during pressure infusion. In this investigation, we tested the air elimination capabilities of the Fluido(®) (The Surgical Company), Level 1(®) (Level 1 Technologies Inc.) and Ranger(®) (Augustine Medical GmbH) pressure infusion devices. Measurements were undertaken with a crystalloid solution during an infusion flow of 100, 200, 400 and 800 ml.min(-1). Four different volumes of air (25, 50, 100 and 200 ml) were injected as boluses in one experimental setting, or infused continuously over the time needed to perfuse 2 l saline in the other setting. The perfusion fluid was collected in an airtight infusion bag and the amount of air obtained in the bag was measured. The delivered air volume was negligible and would not cause any significant air embolism in all experiments. In our experimental setting, we found, during high flow, an increased amount of uneliminated air in all used devices compared with lower perfusion flows. All tested devices had a good air elimination capability. The use of ultrasonic air detection coupled with an automatic shutoff is a significant safety improvement and can reliably prevent accidental air embolism at rapid flows.

CHARACTERIZATION OF THE FLUIDIC PROPERTIES OF A SYRINGE-BASED PORTABLE VITRECTOMY DEVICE

To compare the fluidic properties of the Intrector syringe-based vitrectomy device with other commercially available systems to evaluate its safety in the treatment of vitreoretinal diseases. Mean operator comfortable sustainable syringe plunger pull force was determined using a spring-loaded digital scale. Vacuum levels for syringes of different volumes (3, 5, and 10 mL) and pulling forces were quantified with a pressure transducer. Flow rates of water and egg white were measured both with the cutter at 600 cuts per minute and in the off position with the port open. Infusion flow of water was evaluated using a 1-mL syringe. The mean plunger pull force among operators (n = 8) was 0.80 kg (SD, 0.20 kg). Using the 3-mL syringe with 0.91 kg pull force, mean vacuum level was 135.9 mmHg (SD, 4.8 mmHg) and mean cutter-on flow rates of water and egg white were 1.9 mL/min (SD, 0.1 mL/min) and 0.5 mL/min (SD, 0.1 mL/min), respectively. Larger-bore syringes generated lower vacuum levels and liquid flow rates. The fluidic parameters of the Intrector vitrectomy device measured in this study suggest that at comfortable sustainable syringe pull forces, vacuum levels and liquid aspiration rates are similar to some other commercially available systems and are likely safe.

Development and in vitro evaluation of a flow-adjustable elastic drug infusion pump

Passive-type drug infusion pumps have several advantages over active-type pumps including a simple drug chamber structure and relatively high operational stability. However, conventional passive-type infusion pumps also have several limitations compared to active ejection pumps, such as a fixed flowrate and monotonic flow pattern. To enhance the clinical feasibility of using passive-type drug infusion pumps, flow readjustment and flow regulation abilities are needed. This paper proposes a new portable elastic drug infusion pump that integrates the advantages of active and passive infusion pumps to improve clinical feasibility. The proposed infusion pump incorporates a passively driven drug chamber and an actively adjusted flow controller, which can adjust and regulate various target flowrates and adjust the flow pattern in accordance with the patient's time-varying physiological status. The proposed infusion pump uses the contraction force of an expanded elastic membrane to extract the drug from the drug chamber for delivery into the patient's body through an outlet catheter. It also utilizes a flow sensor, a flow resistor, and a motor-driven flow restrictor that can monitor the real-time flowrate through the outlet catheter and automatically regulate the actual flow-rate around the target value. Experiments on the proposed system resulted in actual injection rates of 0.49 +/- 0.03 (mean +/- standard deviation), 0.98 +/- 0.03, 1.49 +/- 0.04, and 1.99 +/- 0.03 ml/h when the target injection rate was set to 0.5, 1.0, 1.5, and 2.0 ml/h, respectively. During the entire period of operation from the fully filled state to the totally empty state, an inner-chamber pressure of >100 mmHg was maintained, which shows that the proposed infusion pump can stably maintain its target flowrate as the amount of drug remaining to be injected decreases. It appears that the proposed drug infusion pump can be applied to a wide variety of patient treatments that require short-term, accurate, and stable drug delivery.

Infusion pressure and pain during microneedle injection into skin of human subjects

Infusion into skin using hollow microneedles offers an attractive alternative to hypodermic needle injections. However, the fluid mechanics and pain associated with injection into skin using a microneedle have not been studied in detail before. Here, we report on the effect of microneedle insertion depth into skin, partial needle retraction, fluid infusion flow rate and the co-administration of hyaluronidase on infusion pressure during microneedle-based saline infusion, as well as on associated pain in human subjects. Infusion of up to a few hundred microliters of fluid required pressures of a few hundred mmHg, caused little to no pain, and showed weak dependence on infusion parameters. Infusion of larger volumes up to 1 mL required pressures up to a few thousand mmHg, but still usually caused little pain. In general, injection of larger volumes of fluid required larger pressures and application of larger pressures caused more pain, although other experimental parameters also played a significant role. Among the intradermal microneedle groups, microneedle length had little effect; microneedle retraction lowered infusion pressure but increased pain; lower flow rate reduced infusion pressure and kept pain low; and use of hyaluronidase also lowered infusion pressure and kept pain low. We conclude that microneedles offer a simple method to infuse fluid into the skin that can be carried out with little to no pain.

Diffusion of magnetic nanoparticles in a multi-site injection process within a biological tissue during magnetic fluid hyperthermia using lattice Boltzmann method

In this study the lattice Boltzmann model (LBM) has been used to simulate diffusion of magnetic nanoparticles (MNPs) injected at multiple sites inside a biological tissue during magnetic fluid hyperthermia (MFH). To validate the numerical results, diffusion in infinite one and two dimensional domains have been compared with the analytical solutions. Agreement were excellent. Also diffusion of a water based nanofluid containing magnetite MNPs (ferrofluid) for mono and multi-site injection in the tissue has been studied. Moreover, the effects of ferrofluid injection volume as well as infusion flow rate of ferrofluid on the distribution of MNPs have been investigated.

Mechanical performances of elastomers used in diffusers

The use of elastomeric diffusers (EDs) has grown together with the expansion of home care. In these devices, the fill volume of the drug reservoir and the flow rate are preset and cannot be modified. The elastomer, which makes up the reservoir walls, is what makes the infusate flow due to the pressure it exerts. The purpose of this work was to quantify, under standardized experimental conditions and following recommended conditions of use, the mechanical performances of the 2 commonly used elastomers (silicone and polyisoprene) and their impact on infusion flow rate consistency. Results show that they exhibit different mechanical performances which leads to concerns regarding the use of these devices for some intravenous (IV) therapies.

SIMULATING CONVECTION-ENHANCED DELIVERY IN THE PUTAMEN USING PROBABILISTIC TRACTOGRAPHY.

The treatment of brain diseases is complicated by the presence of the blood-brain barrier. This barrier limits the crossing of therapeutic molecules from the blood vessels into the brain. Today, direct intracerebral infusion applying convection-enhanced delivery (CED) is proposed to circumvent this problem and enhance the area of distribution of infusate beyond the parameters of diffusion. Several factors affect the efficacy, predictability and replicability of CED, such as the catheter model, infusion rate and site of infusion. We set out to investigate if probabilistic tractography can be used to model the infusion flow and predict the intracerebral movement of molecules. In this study we describe a modeling and analysis framework based upon probabilistic tractography. This framework was used to compare probabilistic tractography modeling and actual CED infusion measurements in the putamen of non-human primates, as this gray matter structure is proposed as a target for CED treatment of Parkinson's disease.

Technical Evaluation of a New Sterile Medical Device to Improve Anticancer Chemotherapy Administration

To assess the PCHIMX-1 (Doran International), a new sterile medical device intended by its manufacturer to improve the quality and safety of cytotoxic drug infusions, as well as its influence on manipulation times required for pharmacy technicians and nurses and its effect on infusion line outflow parameters. PCHIMX-1 assemblies were compared to standard infusion sets. Pharmacy and oncology units of a French general hospital. Reference assemblies (an infusion bag connected to an infusion set) were compared to PCHIMX-1 assemblies (PCHIMX-1 connected to two bags and to an infusion set). Two assessments were performed: (a) comparison of the times of manipulation during both preparation and administration of 5-fluorouracil infusion bags (n = 40) and (b) effect of PCHIMX-1 on infusion quality. Manipulation times in the pharmacy (TP) and in the ward (TW) were measured, as well as flow rate and infusion efficiency. The results showed that TW was significantly increased, whereas TP was significantly decreased; total time was unchanged. Results also showed that PCHIMX-1 significantly changed infusion efficiency; flow rate was not affected. PCHIMX-1 obliges pharmacy technicians and nurses to change their handling procedures. The device does not have any influence on infusion flow rate but considerably improves infusion quality by ensuring that the full quantity of medication prescribed is administered. PCHIMX-1 guarantees that the complete prescribed dose of chemotherapy is administered without any change in infusion quality and adheres to the latest recommendations concerning occupational exposure protection.

A nonlinear biphasic model of flow-controlled infusions in brain: Mass transport analyses

A biphasic nonlinear mathematical model is proposed for the mass transport that occurs during constant flow-rate infusions into brain tissue. The model takes into account geometric and material nonlinearities and a hydraulic conductivity dependent upon strain. The biphasic and convective–diffusive transport equations were implemented in a custom-written code assuming spherical symmetry and using an updated Lagrangian finite element algorithm. Results of the model indicate that the inclusion of these nonlinearities produced modest changes in the interstitial concentration but important variations in drug penetration and bulk concentration. Increased penetration of the drug but smaller bulk concentrations were obtained at smaller strains caused by combination of parameters such as increased Young’s modulus and initial hydraulic conductivity. This indicates that simulations of constant flow-rate infusions under the assumption of infinitesimal deformations or rigidity of the tissue may yield lower bulk concentrations near the infusion cavity and over-predictions of the penetration of the infused agent. The analyses also showed that decrease in the infusion flow rate of a fixed amount of drug results in increased penetration of the infused agent. From the clinical point-of-view, this may promote a safer infusion that delivers the therapeutic range over the desired volume while avoiding damage to the tissue by minimizing deformation and strain.

Lower esophageal sphincter relaxation reflex kinetics: effects of peristaltic reflexes and maturation in human premature neonates

We defined the sensory-motor characteristics of the lower esophageal sphincter relaxation (LESR) (stimulus threshold volume, response onset, and relaxation period, relaxation magnitude, nadir) during maturation in human neonates. We hypothesized that LESR kinetics differs during maturation and with peristaltic reflex type. Basal and adaptive esophageal motility testing was performed (N = 20 premature neonates) at 34.7 and 39.1 wk (time 1 and time 2). Effects of midesophageal provocation with graded stimuli (N = 1,267 stimuli, air and liquids) on LESR kinetics during esophagodeglutition response (EDR) and secondary peristalsis (SP) were analyzed by mixed models. Frequency of LESR with basal primary peristalsis were different during maturation (P = 0.03). During adaptive responses with maturation, 1) the frequencies of peristaltic reflexes and LESR were similar; 2) liquid stimuli resulted in a shorter LESR response latency and LESR nadir and greater LESR magnitude (all P < 0.05); 3) media differences were noted with LESR response latency (air vs. liquids, P < 0.02); and 4) infusion flow rate-LESR were different (P < 0.01 for air and liquids). Mechanistically, 1) frequency of LESR was greater during peristaltic reflexes at both times (vs. none, P < 0.0001); 2) LESR response latency, duration, and time to complete LESR were longer with EDR (all P < 0.05, vs. SP at time 2); and 3) graded stimulus volume LESR were different for air and liquids (P < 0.01). In conclusion, sensory-motor characteristics of LESR depend on the mechanosensitive properties of the stimulus (media, volume, flow), type of peristaltic reflex, and postnatal maturation. Maturation modulates an increased recruitment of inhibitory pathways that favor LESR.

What Infusion Flow Should Be Used for Mid-Dilution Hemodiafiltration?

Background: There is still no consensus on the optimal infusion flow (Qi) in mid-dilution hemodiafiltration. The aim of this study was to compare mid-dilution with varying Qi. Subjects andMethods: Prospective study in 25 patients who underwent seven hemodialysis sessions with a Qi of 0, 50, 100, 150, 200, 250 and 300 ml/min. Results: All sessions were well tolerated except Qi 300 ml/min. No significant differences in urea, creatinine, α₁-microglobulin or α₁-acid glycoprotein reduction ratios were observed. β₂-Microglobulin, myoglobin and prolactin reduction ratios were higher with Qi 150, 200, 250 and 300 ml/min in comparison with Qi of 0, 50 and 100 ml/min. There were no differences in the removal of small or larger molecules when Qi was 150 ml/min or higher. Conclusions: Optimal Qi in mid-dilution appears to be in the range of 150–250 ml/min since good clinical outcomes, similar efficiency and no technical complications up to a Qi of 250 ml/min were observed.

On-line Measurement of the Resin Infusion Flow Variables Using Artificial Vision Technologies

This paper aims to use artificial vision technologies to measure the resin infusion flow variables. In particular, in this paper is used different artificial vision technologies, visible camera to sense the filling process, IR camera to sense the cure process and a projector to show onto the mould whatever interesting information to carry out the manufacturing process. The devices union is called of Artificial Vision Package (AVP). In this work, the AVP is used as an inverse engineering tool. For a given mould, camera and laser mesh it. By the use of this mesh, and optimization tool computes the optimal channel distribution. This channel is projected into the mould for the proper location. In the injection and curing stage, cameras in the visible and infrared spectrum provide information about the goodness of the process.

Guidelines for automated manual infusion: a practical way of prescribing postdilution on-line hemodiafiltration

Post-dilution on-line hemodiafiltration (OL-HDF) is the most efficient infusion mode to obtain maximum clearances of uremic toxins, with a recommended manual infusion flow (Qi) of 25% of the blood flow with the main limitation that causes alarms by hemoconcentration throughout the session. Recent technical advances allow automatic prescription of Qi if hematocrit and total protein (TP) values are specified. As these analytical results are not possible to obtain in each dialysis session, a practical way to prescribe Qi is to make an automatic prescription adjusting the hematocrit and total protein values at the beginning of the session to obtain the manual prescription required and we will call it automatic-manual prescription. The aim of this study was to compare manual Qi with automatic-manual Qi in postdilution OL-HDF. 30 patients (16 men and 14 women), 59.9 +/- 15 years old, in hemodialysis program for 50.1 +/- 67 months were included. Every patient underwent four OL-HDF sessions, two with manual Qi (4008-S and 5008 monitors) and two with automatic-manual Qi (A-M), one with the same Qi and one with manual Qi +20 (A-M+20). The same usual dialysis parameters were maintained: helixone dialyzer, dialysis time of 266 +/- 39 minutes, blood flow of 420 +/- 36. Recirculation, Kt and intradialysis alarms were measured at each session. No significant differences in the fistula recirculation or dialysis dose measured using Kt. Total infusion volume was 24.9 +/- 4 (4008 S), 23.4 +/- 4 L (5008) with manual Qi, 23.6 +/- 4 L (A-M) Qi (NS) and 25.8 +/- 5 L (A-M+20). Only 14% of patients had no incidents. The number of alarms was significantly higher with manual prescription 55 alarms with 4008 and 40 with 5008 vs. AM (11) p < 0.01) and A-M+20 (16 alarms) We concluded that automatic-manual Qi is a practical way for post-dilutional OL-HDF prescription where the same efficiency and total reinfusion volume with an important reduction of intradialysis alarms are obtained, allowing to rise Qi by 20% without increasing intradialysis alarms.