Drug Infusion Pumps Research Articles

Intrathecal Catheter-Syringe Adaptor for Short-Term Intrathecal Analgesia with an Externalized Pump: A Case Report

Background: In most patients, cancer pain is effectively treated with conservative medical management consisting of oral and/or transdermal analgesics. Cancer patients tend to fail conservative medical management near the end of their life expectancy, thus requiring alternative routes of analgesia such as intravenous, epidural, or intrathecal. The intrathecal route provides the most effective analgesia due to the close proximity of the opioid receptors in the spinal cord. Though there are many techniques that exist for intrathecal drug delivery, complications can limit effectiveness such as infection, bleeding, cerebrospinal fluid (CSF) leaks, post-dural puncture headaches (PDPH), pump and/or catheter malfunctions, or limitations of technical expertise. Therefore, an important goal in palliative cancer pain therapy is to use equipment that is going to have the fewest number of complications and will be the most familiar to the health care providers. We describe the combination of the Medtronic Indura 1P catheter, which has the least catheter-related complications and can be used with any external drug infusion pump. These are regular infusion pumps that the health care workers are familiar with so they can provide excellent and efficient service to the patient. Methods: In an operating room, the intrathecal catheter was placed using sterile technique under fluoroscopic guidance. The epidural space was identified with loss of resistance technique. Then the introducer needle (supplied in the Indura 1P catheter kit) was advanced until free-flowing CSF was obtained. The spinal catheter was advanced into the intrathecal space through the introducer needle to lumbar 2-3 level. The catheter was tunneled subcutaneously 10 cm lateral to the catheter exit site. A syringe filling device was inserted into the catheter opening and was secured with silk suture. A luer lock syringe was attached to the syringe filling device and CSF was aspirated. The syringe filling device was capped and later attached to an external drug infusion pump. Results: We report the successful use of the Medtronic Indura 1P, one piece intrathecal catheter, connected to the external drug pump for a 3 week period in a patient with metastatic cervical cancer for palliative pain control. Limitations: Case report only. Conclusion: This technique is simple to perform by pain specialists. The catheter modification allows the use of the Medtronic intrathecal catheter with standard external drug infusion pumps. This facilitates the patient’s care in the hospice setting. Key words: Intrathecal drug delivery, palliative medicine, intrathecal analgesia, intrathecal catheter complications, cancer pain, end of life pain control

Infraclavicular Fossa as an Alternate Site for Placement of Intrathecal Infusion Pumps

Intrathecal infusion using an implantable pump is a common method of delivering medication for spasticity or chronic pain. The classic site for placement of the pump is in the abdominal wall. In some patients, there are confounding factors that make placement of an abdominal pump impractical. The purpose of this study was to report the implantation of Synchromed II pumps (Medtronic, Inc, Minneapolis, Minnesota) in the infraclavicular fossa. Four patients, aged 13 to 33 years, underwent infraclavicular placement of a Synchromed II infusion pump. In one patient, severe scoliosis and hip joint contractures precluded placement of the pump in the traditional position. Another patient had several ostomies on the abdominal wall, leaving no place for the pump. In a third, a combination of scoliosis and ostomy rendered the abdomen inappropriate for pump placement. In 3 patients, a 20-mL pump was placed in the infraclavicular fossa. In the fourth, a 40-mL pump was placed in the left infraclavicular fossa. All patients tolerated the operation well. There were no postoperative reports of local pain or discomfort. One patient died from unrelated respiratory compromise several months after pump placement. At last follow-up (average of 11 months), the pumps were functioning well, and there were no wound-related complications. Selected pre- and postoperative photographs are presented. The infraclavicular fossa is a viable alternative to the abdomen as the site for placement of a drug infusion pump.

암 환자 통증 조절을 위한 이식형 약물 주입 펌프 개발

This paper presents a implantable intrathecal drug infusion pump for pain control in cancer patients. This device consists of micropump module, drug reservoir module and control module. The micropump module using cam-follower mechanism composed of small-sized four cams and four followers. Each followers is driven by a cam and liquid is discharged by a sequential reciprocal motion of the followers. The advantage of this structure is that it allows the pump to be clean and valveless. The drug reservoir module composed of drug chamber, gas chamber and diaphragm. The control module composed of battery, wireless communication unit and controller. To design a small-sized, low power pump some analysis were performed to determine the design parameters. To verify the feasibility of the experiment, a prototype was manufactured and its operating characteristics were investigated. Experimental results were in accordance with the expected results obtained from analysis.

Impulsivity (delay discounting) for food and cocaine in male and female rats selectively bred for high and low saccharin intake

Previous research in rats indicates that delay discounting for food, a model of impulsivity, predicted the rate of acquisition of cocaine self-administration. In other studies, rats bred for high saccharin intake (HiS) acquired cocaine self-administration at higher rates than those with low saccharin intake (LoS), and female (F) rats acquired cocaine self-administration more rapidly than males (M). The purpose of this study was to examine a possible connection between impulsivity, saccharin intake, and sex by comparing M and F rats from the HiS and LoS selectively bred lines on measures of impulsivity; i.e., their rate of delay discounting for food or i.v. cocaine infusions. The adjusting delay procedure allowed rats access to 2 response levers, and a pellet dispenser or an i.v. drug infusion pump. In 4 groups (HiS M, HiS F, LoS M, LoS F) responses under a fixed-ratio (FR) 1 schedule on one lever resulted in one 45 mg pellet immediately, and responses on the other lever resulted in 3 or 6 pellets after a delay. Four additional groups received either a small cocaine (0.2, 0.4, or 0.8 mg/kg) infusion immediately or a delayed larger infusion (3× the amount of the small infusions). The delay to the larger reinforcer began at 6 s and increased or decreased by 1 s following responses on the delay or immediate levers, respectively. A mean adjusted delay (MAD) was calculated over 30 choice trials during each daily 3-hour session, and it was used as a quantitative measure of impulsivity. In groups maintained by food, HiS rats were more impulsive (lower MADs) than LoS rats, and LoS females were more impulsive than LoS males. There were no phenotype or sex differences in delay discounting for cocaine. Understanding the relationship between impulsivity and other predictors of drug abuse (e.g., sex, saccharin intake) is important in developing prevention and treatment strategies.

Endoscopy in patients with implanted electronic devices

Endoscopy in patients with implanted electronic devices

Changeovers of vasoactive drug infusion pumps: impact of a quality improvement program

BackgroundHemodynamic instability following the changeover of vasoactive infusion pump (CVIP) is a common problem in the intensive care unit. Several empiric methods are used to achieve CVIP. We hypothesized that the variation in these procedures could generate some morbidity. We sought to assess the effects of the standardization of practice, as a quality improvement program, on the CVIP-induced incidents.Materials and methodsWe performed a prospective before-and-after intervention study including all adult patients with a diagnosis of cardiovascular failure who received a continuous infusion of vasoactive drugs or inotropic drugs. After a baseline preimplementation period (phase 1), a standardized 'quick change method' of CVIP using two syringe drivers was implemented in our intensive care unit (phase 2). Endpoints (rate and distribution of incidents: variations of systolic blood pressure >20 mmHg or heart rate >20 beats/min, and arrhythmias) were registered in both 3-month phases.ResultsWe studied a total of 913 CVIP events (phase 1, 435 events; phase 2, 478 events) from 43 patients. Patient characteristics were not significantly different among phases, with a majority of the patients having septic shock. The frequency of incidents was significantly (P < 0.0001) reduced in phase 2 (5.9%, n = 28) versus phase 1 (17.8%, n = 78). This effect was observed whichever catecholamine was used. More than 98% of incidents were blood pressure variations, with a similar distribution of the nature of incidents in both phases.ConclusionThe present study illustrates that adverse events are common following CVIP, and illustrates the positive impact of a quality improvement program to enhance inpatient safety related to this current process of care.

An Error Associated with an Epidural Drug Infusion Pump

An Error Associated with an Epidural Drug Infusion Pump

Infusion Pump Delivers Over-Dosage of Propofol as a Result of Missing Syringe Support

We describe the malfunction of a common drug infusion pump. The syringe saddle was missing and allowed the syringe barrel to contact the pump case, which decreased the outward displacement of the syringe clamp. Then, the infusion pump falsely detected a smaller syringe size and consequently delivered an increased infusion rate and overdose of propofol to the patient. More commonly, an incorrectly mounted syringe may increase the outward displacement of the syringe clamp so that the infusion pump falsely detects a larger syringe size, with resultant less than expected infusion rate.

Medical Devices of the Abdomen and Pelvis

Medical devices in the abdomen and pelvis are probably less frequently seen than those in the chest or extremities, but they are important and should be recognized. These devices can be grouped into a few major categories: intestinal tubes, genitourinary devices, postoperative apparatus, and a wide variety of odds and ends. Many of these devices are used to monitor or treat gastrointestinal and genitourinary disease. Some of them, such as inferior vena cava filters and drug infusion pumps, treat systemic problems, and some of them are devices used in treating another anatomic region. It is strongly recommended that scout views for chest, abdominal, and pelvic computed tomographic studies be carefully examined for medical apparatus. Medical devices are often more easily recognized on scout images, and their inappropriate locations and complications can be better appreciated on the subsequent cross-sectional images if one is alerted to their presence in the first place. The evaluation of routine medical devices should be considered as important as any other aspect of a radiologic examination.

Can cardiac pacemakers and magnetic resonance imaging systems co-exist?

This editorial refers to ‘ In vivo heating of pacemaker leads during magnetic resonance imaging’† by R. Luechinger et al ., on page 376 One of the earliest lessons learned by physicians and technologists working in the field of magnetic resonance imaging (MRI) is that cardiac pacemakers represent a strict contraindication to performing an examination. However, there are multiple examples of implants and devices that previously were contraindicated for MRI and are now allowed within specific guidelines. These include neurostimulation systems, cochlear implants, a drug infusion pump, and a bone fusion stimulator. Because of expanding clinical indications, both MR and pacemaker technology has steadily advanced. It is no surprise then that these two powerful technologies might clash. There has been a steady increase in the number of pacemakers implanted in the United States and worldwide. More than 900 000 pacemakers were implanted worldwide in 2003, and since 1999 implantation rates have increased 5–6% per year. MR systems have been increasing in number as well. There are now ∼15 000 MR systems worldwide, and 35 million MR studies performed yearly. MR is an important diagnostic tool in musculoskeletal, central nervous system, and oncological disorders. It is also rapidly expanding into the cardiovascular arena. Because of its varied clinical applications there are times when denying MR examinations to patients with a pacemaker may have a significant impact on public health. The patients may be subjected to a more invasive or less accurate test which may influence the quality of healthcare. A 1999 Japanese study found that 17% of patients with pacemakers were denied MRI in the previous year.1 Applying those numbers worldwide, the effect could influence the healthcare of over 1 million people. Notably, harmful effects to patients have been documented. To date there have been 10 deaths attributed to … *Corresponding author. Tel: +1 918 592 0999; fax: +1 918 878 2436. E-mail address : martin{at}oklahomaheart.com

The Infection Risk of Intrathecal Drug Infusion Pumps after Multiple Refill Procedures

The objective of this study was to evaluate the long-term infection risk from refilling intrathecal drug delivery devices. We studied 25 patients (14 females and 11 males) with intrathecal infusion pumps placed for spasticity (23 patients) and chronic pain (two patients). In this study group there were 890 refill procedures (mean 35.6±20.5; range 8-72 times) performed on an outpatient basis by four different physicians. All refill procedures were performed in a sterile and standardized fashion as suggested by the manufacturer, using manufacturer's approved kits for the refills. During the study period, five patients had recurrent infection of the urinary tract and three patients had recurrent infections of the respiratory tract. At the last pump refill of each patient, residual drug, extracted from the pump reservoir, was sent to a laboratory for aerobic and anaerobic cultures. All cultures, in all pumps, were negative for aerobic and anaerobic bacteria. We conclude that periodic refills of intrathecal implanted pumps do not seem to be a risk factor for infection if standard sterile refill procedures are performed. In this study, it was clear that comorbid infections from other parts of the body do not present as a risk for device contamination.

Deaths Linked to Drug Infusion Pump Overdosing

Deaths Linked to Drug Infusion Pump Overdosing

Protection of sensitive patient-connected medical devices from the subversive use of mobile telecommunication equipment.

The UK Department of Health has recently advised caution with respect to the uncontrolled use of private mobile telecommunication equipment in designated sensitive hospital areas. This advice, which has clear implications for patient safety and well being, was issued following reports of the interference of automatic drug delivery devices, infusion pumps and other sensitive systems. The difficulty of monitoring relatives, visitors and, occasionally, staff who use such mobile telephones in the sensitive areas has led to an initiative by The Princess Margaret Hospital to automatically and continuously monitor the frequencies used by the mobile telephones and to initiate an alarm should such phones be used within a designated area. This paper describes a protocol for the use of these monitors developed in the Princess Margaret Hospital which is designed to minimize the number of monitoring units while providing optimum departmental cover.

A bolus plus continuous infusion protocol for controlling neuromuscular blockade during anesthesia.

Neuromuscular blockade is controlled during anesthesia by administering either bolus doses or a continuous infusion of a blocking agent. To test whether a constant infusion technique requires less attention and provides better control we used a computer to simulate neuromuscular blockade. Using the model we maintained 95% blockade with mivacurium, atracurium, and vecuronium. It required 1.2 changes per hour to maintain the blockade by continuous infusion; an average of 4.5 bolus per hour were required to maintain blockade by the bolus technique. When the bolus and continuous infusion techniques were combined, only 0.16 changes per hour were required. Atracurium was then given to ten patients during anesthesia, following the bolus plus continuous infusion protocol. After a bolus was given to obtain 100% twitch depression, for tracheal intubation, neuromuscular function was assessed by train-of-four stimulation of the ulnar or facial nerves by observing the resultant muscle movement. When the first twitch of the train-of-four returned, relaxation was maintained by continuous infusion. A bolus was given and the drug infusion rate was changed whenever the level of relaxation changed from the desired one twitch of the train-of-four. The infusion rate was adjusted only 1.12 +/- 0.79 times per hour. The desired level of muscle relaxation was easily controlled using the bolus plus continuous infusion protocol. The infusion scheme might be implemented in future drug infusion pumps.

Portable Data Acquisition and Control Apparatus for Implanted Drug Infusion Pump Interrogation

Now that implantable drug infusion pumps are well established clinically, methods for diagnosing suspected pump failures are needed. The authors previously constructed a benchtop data acquisition and control apparatus to assist our work in developing new pump technology. Although this device is technically capable of in vivo pump monitoring, it is cumbersome. Thus, they recently created a portable interrogation unit with more limited features. This portable pump interrogation apparatus consists of a 32 bit MS-DOS labtop computer, data acquisition software, an analog/ASCII interface, a pressure transducer, and appropriate fluid conduits. Communication between the device and the implanted pump is via a percutaneous needle puncture of the drug reservoir refill septum. This procedure is identical to that employed in a standard pump refill. Pump performance is evaluated by incrementally filling the pump reservoir while simultaneously measuring reservoir pressure. The resulting data are presented on the computer screen as a plot of pressure versus volume that quickly and simply either eliminates or confirms the reservoir pressure source as a failure mode. Diagnostic runs are saved on file for archival purposes. Their benchtop apparatus has been a valuable and reliable tool over many years of use. The authors believe that their portable apparatus will be equally beneficial.

Portable Data Acquisition and Control Apparatus for Implanted Drug Infusion Pump Interrogation

Portable Data Acquisition and Control Apparatus for Implanted Drug Infusion Pump Interrogation

Algorithm to control "effect compartment" drug concentrations in pharmacokinetic model-driven drug delivery.

In most computer-controlled pharmacokinetic model-driven drug infusion pumps, simulation of a linear compartmental pharmacokinetic model is used to compute the rate of intravenous drug infusion required to achieve setpoint central compartment (plasma) drug concentrations. For many drugs, it has been suggested that it is the drug concentration in a hypothetical "effect" compartment, rather than in the plasma, that should be manipulated to achieve maximum control over pharmacologic action. Controlling the effect compartment drug concentration is algorithmically more difficult than controlling the central compartment drug concentration because of the time delay between administration of drug into the central compartment and its subsequent appearance in the effect compartment. Presented in this paper is a model-based dosing algorithm for use in pharmacokinetic model-driven drug infusion devices that target the theoretical effect compartment drug concentration.

Transdermal fentanyl: Suggested recommendations for clinical use

Transdermal fentanyl offers the advantage of providing continuous administration of a potent opioid in the absence of needles and expensive drug-infusion pumps for the treatment of cancer pain. When transdermal fentanyl is initiated, it may be necessary to change the dose every 24–48 hr until an appropriate dose is titrated to the needs of the patient. This should be done by providing short-acting opioids as rescue analgesics for breakthrough pain. Well-accepted principles established for chronic opioid use in cancer pain management should apply to the administration of transdermal fentanyl as well. These include dose titration, the coadministration of adjuvant drugs to counteract opioid side effects and enhance analgesia, and the need to reassess the patient continuously for recurrent tumor and other new sources of pain. Further clinically relevant studies are needed and include 1) the determination of the relative potency of transdermal fentanyl, especially in comparison with oral and parenteral morphine; 2) a prospective study of the side-effect profile of transdermal fentanyl in relationship to oral morphine; and 3) the role of oral transmucosal administration of fentanyl in selection of starting doses of transdermal fentanyl and as a means to provide rescue doses for breakthrough pain.

MR imaging of patients with implanted drug infusion pumps

The influence of magnetic resonance (MR) imaging on the integrity and function of an implantable, programmable drug infusion pump and the distortion of the image by this device were tested. Six identical pumps were tested in magnetic fields of 1.5 T. Pump memory was not affected by the procedure. The pump rotor stalled (no infusion) as long as the device was within the magnetic field. Drug delivery resumed as programmed after the pump was removed from the field. No structural damage to the electrical or mechanical pump components was detected. The pump caused a circular image artifact (a signal dropout) within 8-10 cm of the device. The authors conclude that MR imaging is accurate if the area of interest is at least 10 cm from the pump, and that with awareness of temporary infusion cessation, it is safe to perform MR imaging in patients with this implanted pump.

Draft for comment — Standards Australia drug infusion pumps — Committee HT/18-approval and test specification-medical electrical equipment Part 2: Specific requirements-drug infusion pumps & controllers

Draft for comment — Standards Australia drug infusion pumps — Committee HT/18-approval and test specification-medical electrical equipment Part 2: Specific requirements-drug infusion pumps & controllers