Infusion Tube Research Articles

Con: Early extubation after cardiac surgery does not decrease intensive care unit stay and cost

Con: Early extubation after cardiac surgery does not decrease intensive care unit stay and cost

Properties of multiphase microspheres of poly(D,L-lactic-co-glycolic acid) prepared by a potentiometric dispersion technique.

Multiphase microspheres of poly(D,L-lactic-co-glycolic acid) (PLGA) were prepared by a multiple emulsion potentiometric dispersion technique. Water-soluble compounds were dissolved in the aqueous phase (W) and emulsified in soybean oil (O) to form a stable emulsion. This primary emulsion was dispersed in a solution of PLGA and acetonitrile (O) to form a W/O/O emulsion. The W/O/O emulsion was then dispersed in a hardening solution of light mineral oil (O) using a potentiometric dispersion technique to produce microspheres of the W/O/O/O type with a very narrow and selective size distribution. The size of the microspheres was controlled by varying the internal diameter of the conductive infusion tube or by the variation of voltage applied to the conductive tube. Particle size analysis revealed a particle size distribution of 1-50 microns for microspheres made by this method as compared to a distribution of 50-500 microns for microspheres made by conventional agitation methods. Chlorpheniramine maleate was encapsulated with a loading efficiency of 88.9% with the potentiometric method as compared with a loading efficiency of 74.3% for the agitation method.

Is the i.v. obstructed or infiltrated? A simple clinical test.

The objective of our study was to determine if clinical observation of pressure-flow relationships (PFR) can differentiate between partial external obstruction (obstruction) and infiltration as a cause of poor performance of gravity-fed infusions. A total of 24 patients with functional intravenous cannulae in situ had obstruction simulated by the application of a tourniquet proximal to the cannula. The change in flow (delta F) for a discrete change in pressure (delta P) was determined in each case by counting drop rates at two different elevations of the fluid reservoir level, 10 cm apart. The same process was repeated in 15 patients in whom the cannula was in an extra vascular location (infiltration). Three sizes of cannula--16-gauge, 18-gauge, and 20-gauge--were examined, with equal distribution of sizes in each group. The effect on flow rates of inflating a blood pressure (BP) cuff proximally on the cannulated limb was assessed. The ratio delta P/delta F is the total resistance of the infusion system, and by subtracting known values for resistance of infusion tubing and cannula, the venous or tissue resistance was calculated. There was a statistically significant difference between the change in flow for obstructed compared with infiltrated cannulae for the same change in pressure for each cannula size. The mean venous resistance was 23 mm Hg/L/hr, while that of tissue was 280 mm Hg/L/hr, with no overlap between groups. There was no effect on flow rate with blood pressure cuff inflation in the infiltrated group whereas flow progressively fell in the obstructed group. Clinical observation of PFRs in poorly functioning gravity-fed IV infusions can assist in detecting infiltration as a cause. Inflation of a blood pressure cuff will further impair flow where the cannula is intravascular, but will have no effect in an extravascular location.

A thermal flow sensor for infusion technique

A flow sensor for measuring flow rates in infusions systems, which is thus suitable for infusion monitoring, is described. The sensor employs a combination of thermal heating and thermal tracing to determine the flow rate. Heating and sensing elements are applied to the outside of the infusion tubing, so that measurement does not compromise the integrity of the tubing. Through the use of two sensor units measurement can be made independently of position.

Determination of Fat-Soluble Vitamins by Liquid Chromatography in Pediatric Parenteral Nutritions

Abstract A reversed phase high performance liquid chromatographic method using narrow-bore columns packed with 3 μm particles is described for the simultaneous determination of transretinol, ergocalciferol, DL-α-tocopherol and phytomenadione. The fat-soluble vitamins were separated in a C18 bonded phase column and eluted with methanol as the eluent pumped at a flow rate of 0.2 mL/min. A spectral detector was used and the wavelenghts were set at 325, 265, 284 and 250 nm for vitamin A, D2, E and K1 respectively. All vitamins were separated in less than 13 minutes. This method was applied to the determination of fat-soluble vitamins in the pediatric parenteral nutritions. The effect of the nutrition composition, daylight and the plastic infusion tubing on the stability of the vitamins was studied. Recovery studies showed good results for all solutes (191.0% −110.5%) and the coefficients of variation were always less than 3%.

Gastroesophageal Reflux-induced Bronchoconstriction: An Intraesophageal Acid Infusion Study Using State-of-the-Art Technology

To study mechanisms of gastroesophageal reflux-induced bronchoconstriction during intraesophageal infusions. Prospective study blinded to the subject. Outpatient pulmonary function laboratory at a 908-bed university hospital. Forty-seven adult subjects divided into four groups: asthmatics with reflux, 20; asthmatics, 7; gastroesophageal refluxers, 10; and normal controls, 10. Asthmatics were defined by American Thoracic Society criteria, and refluxers were defined by symptoms and 24-hour pH monitoring. Dual antimony esophageal pH probe placed just below the upper esophageal sphincter and 5 cm above the lower esophageal sphincter. Intraesophageal infusions of normal saline solution followed by 0.1N hydrochloric acid then normal saline solution were given for 15 to 18 min. Spirometry and specific airway resistance (SRaw) were performed after placement of pH probes, insertion of esophageal infusion tube, and after each infusion. Bernstein tests were assessed during esophageal infusions. Peak expiratory flow rate (PEF) decreased with intraesophageal acid in all four groups (p < 0.014). Esophageal acid clearance improved PEF in all groups except the asthmatics with reflux group that had a further decrease in PEF. These effects were not dependent on a positive Bernstein test or evidence of proximal reflux. The asthmatics with reflux group also had an increase in SRaw with intraesophageal acid, which continued to increase despite acid clearance. Intraesophageal acid infusions caused a decrease in PEF in all groups without evidence of microaspiration, implying a vagally mediated reflex may be involved. Esophageal mucosal inflammation, assessed by a positive Bernstein test, was not required. Asthmatics with reflux also had further decline in PEF despite acid clearance.

A simple method for internal perfusion of mammalian central nervous system neurones in brain slices with multiple solution changes

A simple system for internal perfusion of whole-cell patch-clamped neurones in brain slices allowing multiple, fast solution exchanges is described. With this system, perfusing solutions can be loaded immediately before use during the recording. At perfusion rates of 5-10 microliters/min, complete replacement of solutions in the patch pipette tip, as determined by changes in the pipette resistance and liquid junction potential, was achieved in less than 20 s. This occurred after a 1-min latency that was due to solution flow through the infusion tube. The effectiveness of the system was tested on rat hippocampal CA1 neurones in the slice preparation. The effects of replacement of internal 150 mM K+ by 150 mM Cs+ ions on voltage-activated K+ currents and of changing internal [Cl-] between 20 mM and 150 mM on evoked GABAA-mediated inhibitory postsynaptic currents (IPSCs) were studied. The blockade of K+ currents by Cs+ ions and the changes of IPSCs by altered internal [Cl-] ion concentration were achieved within 3.2 and 1.5 min, respectively, including the 'flow latency' of about 1 min, and recovery following solution change occurred within 5.2 and 1.5 min, respectively. More than 10 effective internal solution replacements could be performed within 1 h in a single neurone without affecting the recording stability.

Microbial contamination of enteral feeding solution and its prevention

In an investigation of microbial contamination of enteral feeding solutions, all 22 residual solutions obtained immediately after administration were contaminated at concentrations of 10 3 to 10 6 viable counts/ml. Major contaminants were glucose-nonfermenting gram-negative bacilli such as Pseudomonas aeruginosa and Acinetobacter calcoaceticus var anitratus. Contamination seemed to have been caused by frequent reuse of bag-type containers and the infusion tubes connected to the bags, neither of which can be washed or dried. Decontamination methods were evaluated by using polypropylene containers that can be washed and disinfected for administration. Few Serratia marcescens on the inside wall of the container were removed by rinsing with tap water, alone or in combination with detergent scrub. Tap water and detergent plus air-drying at 56° C for 1 hour reduced Serratia marcescens only somewhat. Tap water and detergent plus immersion in 0.01% sodium hypochlorite for 1 hour or in water at 70° C for 3 minutes eliminated all 10 11 cells of Serratia marcescens.

Uptake of solutes by plastic infusion tubing mathematical solutions

The uptake of solutes from aqueous solutions by plastic containers has received considerable attention in recent years. However, the loss of solute from aqueous solutions during flow through plastic tubing has not been as extensively investigated. In this work, the authors present four models to describe the sorption of solute during flow through tubing. These models represent the solution as either a well-stirred compartment or convection flow in a tube, and the plastic as either a well-stirred compartment or a matrix in which diffusion occurs in a radial direction. The time course of outflow solute concentrations observed experimentally after solute infusion into either Tygon or polyvinylchloride tubing was well described by the analytic solutions obtained. The diffusion models appeared to give the more satisfactory fit of the data. However, the data fit showed only small qualitative differences compared to the comportment models. A number of parameters are required to define each model limiting their usefulness. Accordingly, a number of simulations were undertaken to determine he relative effect of each parameter on the outflow concentration profile. As anticipated, the flow rate, the plastic water partition coefficient and the nature of the tubing were important. Extensive loss is most likely at low flow rates when a solute has a high affinity for the infusion tubing.

Side effects during adenosine thallium imaging with single-port or double-port infusion protocols

The double-port infusion protocol during adenosine thallium imaging involves the use of two infusion systems, one for adenosine and one for thallium. The single-port infusion protocol, on the other hand, uses one infusion system; both adenosine and thallium are injected via a “Y” connection. This study examined the possibility that the single infusion system, by displacing a column of blood filled with adenosine, may be responsible for a greater incidence of side effects. In a parallel study, 140 patients underwent adenosine thallium imaging with the single-port system (group 1) and 140 patients underwent imaging with the double-port system (group 2). Both groups were comparable in age (67 ± 10 years vs 64 ± 11 years), gender (men comprised 56% of patients in group 1 and 64% in group 2), resting heart rate, and systolic blood pressure. More patients in group 1 had chest pains (57% vs 44%; p = 0.03), ST-segment depression (25% vs 9%; p = 0.005), nausea (11% vs 4%; p = 0.04), and second- or third-degree atrioventricular block (11% vs 5%; p < 0.08) than did patients in group 2. The other side effects were similar, and peak heart rate and peak systolic blood pressure were also similar. The thallium images that used single-photon emission computed tomography were abnormal in 61% of patients in group 1 and in 65% of patients in group 2 ( p = not significant). The images were of high quality in all but two patients, both in group 1, who had poor images because of low counts, possibly because of backflow of thallium into the adenosine infusion tubing. Thus the use of a single-port infusion system during adenosine thallium imaging is associated with a greater incidence of side effects, possibly because of a bolus effect. A slower rate of thallium injection, the use of a double-lumen catheter, or preferably, the use of double-port infusion systems is suggested to decrease the number of side effects.

Microbial contamination of enteral feeding solution and its prevention

In an investigation of microbial contamination of enteral feeding solutions, all 22 residual solutions obtained immediately after administration were contaminated at concentrations of 10 3 to 10 6 viable counts/ml. Major contaminants were glucose-nonfermenting gram-negative bacilli such as Pseudomonas aeruginosa and Acinetobacter calcoaceticus var anitratus. Contamination seemed to have been caused by frequent reuse of bag-type containers and the infusion tubes connected to the bags, neither of which can be washed or dried. Decontamination methods were evaluated by using polypropylene containers that can be washed and disinfected for administration. Few Serratia marcescens on the inside wall of the container were removed by rinsing with tap water, alone or in combination with detergent scrub. Tap water and detergent plus air-drying at 56° C for 1 hour reduced Serratia marcescens only somewhat. Tap water and detergent plus immersion in 0.01% sodium hypochlorite for 1 hour or in water at 70° C for 3 minutes eliminated all 10 11 cells of Serratia marcescens.

Identification of epidural space by drip method.

In 100 pregnant women, identification of the epidural space was performed by a modified drip method. A saline infusion was prepared, leaving the distal 40 cm of infusion tubing full of air, and then attached to the hub of a Tuohy needle. Accurate identification of the epidural space was accomplished in less than one minute in 95% of cases. There were no unintentional dural punctures. This technique has advantages over the hanging drop and the manual loss of resistance techniques.

Another Cause for Obstruction of Intravenous Infusion Tubing

Another Cause for Obstruction of Intravenous Infusion Tubing

Compatibility of Ketorolac Tromethamine Injection with Common Infusion Fluids and Administration Sets

The compatibility of ketorolac tromethamine injection with commonly used i.v. infusion solutions and administration set components was evaluated. The infusion solutions tested were 0.9% sodium chloride injection, 5% dextrose injection, 0.9% sodium chloride and 5% dextrose injection, Plasma-Lyte A pH 7.4 injection, Ringer's injection, and lactated Ringer's injection. The ketorolac tromethamine admixture concentration studied was 30 mg/50 mL for all solutions. Admixtures were stored in polyvinyl chloride bags and glass bottles at room temperature under fluorescent light and sampled at 0, 6, 24, and 48 hours. Chemical compatibility was determined by high-performance liquid chromatography, and physical compatibility was determined by visual analysis, counting of subvisible particles by HIAC, and pH measurements. Adsorption of ketorolac tromethamine to i.v. administration set components was also evaluated. Ketorolac tromethamine exhibited excellent physical and chemical stability in all six infusion solutions tested. No degradation of drug, formation of particulates, or adsorption to containers or infusion tubing was noted at any concentration for any of the solutions. After the solutions were mixed, the pH remained essentially unchanged. Ketorolac tromethamine injection was physically and chemically stable when mixed with a variety of commonly used infusion solutions and was not adsorbed to administration set components or to glass or polyvinyl chloride containers.

Prediction of flow capability in intravenous infusion systems: implications for fluid resuscitation

The pressure-flow (P-F) relationship for intravenous infusion systems is nonlinear and may be expressed by the quadratic model P = RLF + RTF2. The flow parameters RL and RT may represent the resistance of laminar and turbulent flow, respectively. In this study pressure and flow were measured, and RL and RT were calculated for several infusion tubings, catheter, and system components. We then developed a technique to identify the relative effect of various devices on achieving the higher flows needed for fluid resuscitation. A typical infusion system was chosen, and the experimentally determined flow parameters RL and RT of its components were used in the quadratic P-F relationship at P = 300 mm Hg. Devices in the infusion system were ranked, using a subtractive algorithm, according to their relative impediment to flow as measured by contribution to the pressure drop. The order of devices removed or replaced, from largest to least pressure drop, was as follows: fluid warmer, 16-gauge catheter, check valve, 14-gauge catheter, standard-bore Y tubing, 12-gauge catheter, and standard-bore stopcock, leaving 10-gauge catheter + wide tubing. Devices with large RT, such as fluid warmers and check valves that produce large pressure drops, should generally be avoided during fluid resuscitation when high flows are needed. A similar ordering of device removal or substitution (largest to least pressure drop) was determined using the traditional but incorrect linear P-F model, P = RF, and the order of devices chosen for elimination was different.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of accuracy of intraesophageal pH probe in a dog model.

We performed an experiment in dogs in order to assess the accuracy of an intraesophageal pH probe and to examine possible mechanisms for any lack of accuracy. Two pH probes were placed in the esophagus of supine anesthetized dogs and acid was infused in small serial volumes from an infusion tube placed at the gastroesophageal junction. Two general patterns of pH probe responses were seen: (1) neither probe recorded a fall in pH with acid infusion, and (2) both probes recorded a fall in pH, but in a nonsynchronous manner. Changing the relationship of the tips of the probes with respect to the adjacent mucosa caused a fall in the pH recorded by each probe to the pH of the intraesophageal infusate. This and other evidence seen in the pH tracings suggest that mucosal abutment of the probe tips causes a falsely negative pH recording and raises the question of whether such a phenomenon occurs in human studies.

Use of a Scalp Vein Infusion Set in Oculoplastic Surgery

The scalp vein infusion set is a sterile, readily available device which has been used in a variety of oculoplastic procedures. Segments of the infusion tubing have been employed as bolsters for eyelid traction, tarsorrhaphy, and skin sutures. The tubing may also be placed in wounds for improved drainage. The material has enhanced postoperative wound care and has not been associated with significant complications.

Incidence of infection related to arterial catheterization in children: a prospective study.

The incidence of infection related to arterial catheterization has not been studied in critically ill children, using systematic catheter cultures. We studied prospectively 68 children in whom 70 arterial catheters were inserted. After the aseptic catheterization procedure, no component of the system was changed. The insertion site was inspected daily for signs of inflammation. Upon removal, catheters were cultured using a semiquantitative method. Blood and infusion fluid specimens were also cultured if septicemia was clinically suspected. Mean duration of catheterization was 59 +/- 6 (SE) h. In our series, all catheter and infusion fluid cultures were negative. Local inflammation was not predictive of catheter tip infection and correlated poorly with duration of catheterization (r = 0.2). In our experience, the incidence of infection related to arterial catheterization is low. Routine change of infusion fluid, tubing, dressing and insertion site as well as systematic catheter culture in the absence of fever appears unwarranted.

Malfunction of continuous subcutaneous insulin infusion systems: a one-year prospective study of 127 patients.

Malfunction of portable continuous subcutaneous insulin infusion (CSII) systems may result in either ketoacidosis or serious hypoglycemia. To determine the types and frequencies of infusion system failure and the resulting clinical consequences, we recorded their occurrences in a 1-yr prospective study of 127 patients who were using insulin infusion pumps in a clinical practice setting. Of the 127 patients, 109 (86%) experienced at least one infusion system failure during the study. Most of the infusion system failures (96%) occurred in the syringe, infusion tube and connections, or subcutaneous infusion site. Virtually all malfunctions resulted in interruption of insulin flow, and most were associated with temporary loss of diabetes control. Equipment malfunction was documented in 6 of 7 patients who used insulin pumps and were treated in our hospital for diabetic ketoacidosis during the study. Pump "runaway" was not observed. We conclude that infusion system malfunction resulting in interruption of insulin flow is a common occurrence, is often associated with temporary hyperglycemia, and may account for some of the increased incidence of diabetic ketoacidosis previously described in these patients.

Stability and availability of cyclosporine in 5% dextrose injection or 0.9% sodium chloride injection

The stability of cyclosporine in commonly used i.v. solutions and the percentage of the drug delivered via polyvinyl chloride administration tubing were studied. Cyclosporine injection was prepared according to the manufacturer's instructions and diluted with 5% dextrose injection (D5W) or with 0.9% sodium chloride injection (NS). Admixtures containing cyclosporine 2 mg/mL were prepared in polyvinyl chloride minibags (five for each solution) and in glass containers (three for each solution). The sample obtained at time zero from a glass container protected from light was the control. Additional samples were prepared in minibags and run through 70-inch polyvinyl chloride administration sets. An HPLC assay for cyclosporine was used. Exposure to room light did not significantly affect cyclosporine concentrations. More than 90% of the initial drug concentration remained after 24 hours under all storage conditions, but less than 95% remained after 6 hours in samples diluted with NS and stored in plastic. At times up to 60 minutes, cyclosporine concentrations were significantly different in solutions infused from the minibags through polyvinyl chloride tubing from those in control solutions. Under these conditions, cyclosporine is stable in D5W in glass containers or polyvinyl chloride minibags for 24 hours and in NS for 6 hours (polyvinyl chloride) to 12 hours (glass). However, because of the potential for leaching of plasticizers, cyclosporine admixtures should be stored in glass or used within six hours if stored in polyvinyl chloride minibags. Approximately 10% of the initial drug concentration is lost to 70-inch length polyvinyl chloride infusion tubing.