Implantable Infusion Pump Research Articles

More than pacemakers and defibrillators: perioperative management of implantable devices for patient safety.

The use of implantable medical devices (IMDs) continues to increase with estimates that 10% of the American population will have an IMD in their lifetime. IMDs require special considerations for management in the perioperative period to ensure optimal patient care and patient safety. This review summarizes the current perioperative considerations for IMDs. This review summarizes perioperative recommendations for spinal cord stimulators, deep brain stimulators, peripheral nerve stimulators, vagus nerve stimulators, muscle stimulators, intrathecal drug delivery systems, implantable infusion pumps, artificial pancreas devices, continuous glucose monitors, and cochlear implants. There are multiple publications and guidelines regarding the perioperative considerations of cardiac implantable electronic devices; thus, this review excludes those devices. This review includes recommendations on management of the device perioperatively, the potential complications, and postoperative care of the device. There are very few guidelines regarding the perioperative management of IMDs. Given the significant impact that these devices have on patient care and safety, evidence-based guidelines should be established.

Intravenous Treprostinil in Severe Inoperable Chronic Thromboembolic Pulmonary Hypertension Using Implantable Pumps-Single-Center Experience over More Than a Decade.

The management of chronic thromboembolic pulmonary hypertension has significantly changed over the last decade with the availability of both specific therapies and interventional treatments. In parallel, implantable pumps for intravenous administration of treprostinil have broadened the spectrum of continuous prostanoid infusion. We evaluated the course of 17 consecutive patients with inoperable chronic thromboembolic pulmonary hypertension treated with treprostinil by means of an implantable infusion pump between 2011 and 2023 at our center. Complications associated with the infusion system were rare, leading to 0.4 unplanned surgical interventions during 17,160 patient days. No additional safety signals were detected, and clinical benefits achieved with subcutaneous treprostinil before pump implantation could be maintained in all patients. No catheter-related infections or thromboembolic events were observed. Implantable infusion pumps offer an attractive alternative to subcutaneous treprostinil for patients intolerant to the subcutaneous route, including those with chronic thromboembolic pulmonary hypertension.

Experiencia de la neuromodulación en un hospital de alta complejidad

Neuromodulation is a medical practice established for more than forty years. In the neurosurgical field it plays a role in the treatment of different diseases (Parkinson, Dystonia, Epilepsy, etc) and has a great potential to apply in other pathologies (Obsessive Compulsive Disorder, Pelvic pain). In the last years the biotechnological industry has quadrupled the investment in this field because of the demand and therapy application. Neuromodulation encompasses other specialities, for example otorhinolaryngology in cochlear implants, in cardiology with different models of pacemakers, endocrinology with implanted infusion pumps, urological gynecology in incontinence treatments, etc. Our institution -the Hospital Italiano de Buenos Aires- applies all these techniques in its clinical practice, having a hierarchical role as a reference center in education and health policies. Due to these aspects, added to its infrastructure, professional staff and health approach, it can be considered as a reference Neuromodulation Center in the region.

Experimental investigation on effect of accelerated speed and rotor material on life of implantable micro-infusion pump tubing

Peristaltic pumps have been put to use in various biomedical applications like devices for the transfer of body fluids as well as devices for controlled release of medication, including implantable infusion pumps. Out of the various components of a peristaltic pump, tubing is considered the most vulnerable part. This study focuses on the performance of Silicone micro-pump tubing used in such an implantable drug delivery device. Long-term implantable medical devices are expected to be operational for about 10 years. But experimental testing of the reliability of components under normal working speeds are time-consuming and thus delays the product development cycle. While simulating the conditions in the laboratory under accelerated speeds, the effect of increasing the speed must be accounted. In this study, the effect of accelerated speed and rotor material on pump tubing life is investigated. A test jig is developed which simulates the running conditions of the infusion pump for long-duration operation. Different rotor speeds and material configurations are investigated to obtain their effect on long-duration performance. Thermal effects on the roller junctions are studied and found that the Delrin silicone combination has twice the rise in junction temperature than the titanium silicone combination. The failure modes are inspected using microstructure analysis and the best configuration is identified.

The impact of strategies to manage the COVID-19 pandemic on patients with intrathecal baclofen therapy.

The activities related to intrathecal baclofen (ITB) therapy could not be interrupted at the outbreak of COVID-19 pandemic due to possible life-threatening related complications such as withdrawal and over dosage syndromes. In this study we reported the different adopted strategies to manage patients with an ITB implanted infusion pump during the pandemic period and studied the impact of these strategies on experiences reported from patients and their caregivers, assessed through a specific survey. Thirty-five patients (mean age: 43.71±12.33 years) were included. Their clinical and medical data were recorded and observed from March 2020 to March 2021 and different strategies implemented in order to limit patients and providers risk of exposure to COVID-19. The impact of these strategies was assessed trough a survey that was performed after the first two months of pandemic (coinciding with the period of general lockdown) and after one year from the pandemic onset. We observed a statistically significant improvement of the following items: difficulties in reaching medical clinic (P=0.0072), continuation of physical therapy (P=0.0021) and feelings of anxiety in medical conditions (P=0.0006). Considering the difficulties in communications with the medical staff we obtained optimal scores both at the beginning of pandemic and after one year from the pandemic onset without significant difference. Our survey showed that the adopted strategies provided a feeling of confidence and safety among ITB patients and their caregivers during the COVID-19 pandemic. We think that a clear communication is always of paramount importance to manage these patients.

Novel Approach for Laparoscopically Placed Chronic Amniotic Fluid Catheters in Sheep

Introduction: Several fetal therapies involve repeated amniotic fluid intervention. We hypothesize that a minimally invasive approach can be used to safely implant an intrauterine catheter infusion system in a fetal ovine model for chronic use during pregnancy. Method: Five pregnant sheep underwent operation between gestational days 110 and 115 (term 145 days). A Codman® implantable infusion pump was adapted for intrauterine use. The chamber was placed in the maternal flank and the tunneled catheter laparoscopically inserted into the amniotic cavity, secured with a pursestring. Three had an additional uterine anchoring suture. Ewes were sacrificed after natural delivery, and the uterus underwent gross and microscopic analyses. Results: There were no maternal mortalities, abortions, or preterm labor. Pumps were accessed and remained functional throughout gestation. Four ewes delivered healthy term lambs; the other delivered twins with failure to progress and demise. On necropsy, catheters secured with an anchoring suture remained in place, while the other 2 dislodged during labor. There was no chorioamnionitis by culture or histology. Conclusion: Laparoscopically placed intra-amniotic infusion catheters were implanted safely and remained functional until delivery in an ovine model. This novel approach has promise in providing safe, durable amniotic fluid access for the potential treatment of fetal disease.

Anesthetic considerations in patients with implantable devices and chronic pain surgery

The use of advanced invasive techniques for the control of chronic pain in patients with multiple comorbidities is becoming increasingly common. Neuromodulation offers a new management alternative involving the infusion of one or more drugs into the epidural or intrathecal space through a fully implantable infusion pump. It also involves spinal stimulation, a minimally invasive technique in which electrodes are positioned in the epidural space and connected to a pulse generator that is implanted subcutaneously and generates pulses designed to suppress the noxious stimulus. This article will describe the anesthetic considerations in cases of implantable drug delivery systems, and spinal and peripheral nerve stimulation devices. Additionally, patients with electrical or drug neuromodulation devices may present to anesthetic practice for surgical indications unrelated to their chronic pain pathology. Hence the importance of being familiar with the basic components of these devices, how they work, what drugs they use and the potential associated complications in the perioperative context, in order to ensure proper management and patient safety.

Rapid Switch From Subcutaneous to Intravenous Treprostinil in Precapillary Pulmonary Hypertension by Pump Implantation.

Limited data are available on the transition from subcutaneous to intravenous prostacyclin in precapillary pulmonary hypertension. We performed a retrospective analysis of all patients who were switched from subcutaneous to intravenous treprostinil with an implantable infusion pump. We included 85 consecutive, clinically stable patients (mean age 66 years and range 16-85), who had been treated with subcutaneous treprostinil for mean 9 months (range 1-78) before pump implantation. An interdisciplinary expert panel defined standards for this procedure before the first implantation. As the first patient experienced a significant hypotensive episode indicating treprostinil overdose postoperatively, the time span to stop subcutaneous treprostinil was reduced to 60 minutes for all following patients. No events associated with the switch from subcutaneous to intravenous treprostinil were observed during postoperative hospital stay in 84 (98.8%) patients. Taking into account a likely depot effect of subcutaneous treprostinil patients can safely be switched to the intravenous route by the implantation of an infusion pump.

Long-term experience with implantable infusion pumps for intravenous treprostinil in pulmonary arterial hypertension-procedural safety and system-related complications.

Implantable pumps for intravenous treprostinil provide a promising option to overcome drawbacks of parenteral prostanoid administration with external pumps in pulmonary hypertension. We retrospectively analyzed 85 patients undergoing implantation in a single center since 2010. In our cohort, serious complications were rare, and flow rate increase over time warrants careful monitoring.

Treprostinil in the treatment of pulmonary arterial hypertension.

Despite progress over the past 30 years, pulmonary arterial hypertension remains a condition with high morbidity and mortality. Pharmacological and technological advances have shifted the approach to treating pulmonary arterial hypertension. Recent developments revolve heavily around novel routes of drug administration and delivery. In 2009, inhaled treprostinil was approved followed by oral treprostinil in 2013 providing patients with more convenient routes of administration compared with the parenteral alternatives. We are on the cusp of having the first fully implantable infusion pump for continuous intravenous treprostinil delivery. In 2019, generic treprostinil was approved, making the medication much more affordable for patients. In this review, we discuss in detail the recent developments surrounding both traditional and novel treprostinil products.

Flow rate variance of a fully implantable pump for the delivery of intravenous treprostinil in pulmonary arterial hypertension.

Implantable infusion pumps might improve the convenience and safety of intravenous treprostinil for pulmonary arterial hypertension. The LENUS Pro® pump (approved in Europe) has a fixed flow rate. Based on 126 pumps and 2853 refills, we retrospectively analyzed the actual flow rate from 09/2010 to 09/2018. A relevant flow rate variance is evident after three years; therefore, flow rate monitoring and dose adjustment are mandatory.

MR safety assessment of active implantable medical devices.

Increasing numbers of patients with active implantable medical devices (AIMDs) require magnetic resonance (MR) examinations. The manufacturers are continuing to improve the MR compatibility of their AIMDs. To this end, avariety of measurement methods and numerical simulations are used to evaluate the risks associated with magnetic resonance imaging (MRI). In this article, test methods used to investigate interactions between AIMDs with radio frequency fields and time-varying magnetic gradient fields are reviewed. A literature review of known test methods for radio frequency and gradient field exposure of AIMDs with leads, in particular for neurostimulators, cochlear implants, and implanted infusion pumps, is presented. The state of the art and promising methods are discussed. ISO/TS 10974 describes the design of high frequency and gradient injection setups to test conductive materials. A large number of sensor designs have been published to measure the induced voltages and currents through radio frequency and gradient fields and for monitoring AIMDs during MR examinations in in vitro tests. The test methods should be planned to be as conservative as possible to cover the worst case scenario. However, in vitro measurements and computer simulation are far from being able to cover all possible configurations in their complexity and uniqueness. For safer MR examinations, current research recommends in vivo testing prior to MR, parallel radiofrequency transmission techniques, and new sequences with reduced energy input in the presence of AIMDs.

MR safety assessment of active implanted medical devices. German version

Increasing numbers of patients with active implantable medical devices (AIMDs) require magnetic resonance (MR) examinations. The manufacturers are continuing to improve the MR compatibility of their AIMDs. To this end, avariety of measurement methods and numerical simulations are used to evaluate the risks associated with magnetic resonance imaging (MRI). In this article, test methods used to investigate interactions between AIMDs with radio frequency fields and time-varying magnetic gradient fields are reviewed. A literature review of known test methods for radio frequency and gradient field exposure of AIMDs with leads, in particular for neurostimulators, cochlear implants, and implanted infusion pumps, is presented. The state of the art and promising methods are discussed. ISO/TS 10974 describes the design of high frequency and gradient injection setups to test conductive materials. A large number of sensor designs have been published to measure the induced voltages and currents through radio frequency and gradient fields and for monitoring AIMDs during MR examinations in in vitro tests. The test methods should be planned to be as conservative as possible to cover the worst case scenario. However, in vitro measurements and computer simulation are far from being able to cover all possible configurations in their complexity and uniqueness. For safer MR examinations, current research recommends in vivo testing prior to MR, parallel radiofrequency transmission techniques, and new sequences with reduced energy input in the presence of AIMDs.

Upper Antero-Medial Thigh as an Alternative Site for Implantation of Intrathecal Pumps: A Case Series

Neuraxial drug delivery via intrathecal drug delivery systems (IDDS) is becoming an increasingly common mode of treating intractable cancer-related pain, chronic pain, or severe spasticity. An implanted infusion pump delivers medication into the intrathecal (subarachnoid) space via a thin catheter. These pumps are commonly placed in the anterior abdominal wall. Certain conditions may render it difficult or unsafe for an IDDS to be implanted at the traditional site; thus, alternative sites have been explored. We report on the use of the upper antero-medial thigh as a safe alternative site for this purpose. Nine patients between 22 and 69 years of age underwent placement of an IDDS infusion pump in the upper antero-medial aspect of one thigh. In each patient, the anterior abdominal wall was precluded for implantation due to various reasons, such as extensive abdominal scar tissue from previous surgeries, placement of feeding tubes and ostomies, large ventral hernia or metastatic masses protruding from the abdomen. Nine patients, with ages ranging from 22 to 69 years old, had IDDS implantation in the upper thigh. The first patient experienced wound dehiscence (antero-lateral location) and after explantation, another pump was placed successfully in the opposite thigh (antero-medial location). One patient has had pump replacement due to end-of-battery life. She also needed an unrelated catheter revision. Seven patients have expired from their disease progression after living for an average of 142.7 days (range 50 days to 354 days) while two patients continue to experience relief from pain and spasticity years later (see Table 1). No neurovascular damage, infections, or other complications occurred in our series. The upper antero-medial thigh is a safe alternative to the anterior abdominal wall for implantation of an IDDS.

Assessment of implantable infusion pumps for continuous infusion of human insulin in rats: potential for group housing.

Group housing is considered to be important for rats, which are highly sociable animals. Single housing may impact behaviour and levels of circulating stress hormones. Rats are typically used in the toxicological evaluation of insulin analogues. Human insulin (HI) is frequently used as a reference compound in these studies, and a comparator model of persistent exposure by HI infusion from external pumps has recently been developed to support toxicological evaluation of long-acting insulin analogues. However, this model requires single housing of the animals. Developing an insulin-infusion model which allows group housing would therefore greatly improve animal welfare. The aim of the present study was to investigate the suitability of implantable infusion pumps for HI infusion in group-housed rats. Group housing of rats implanted with a battery-driven pump proved to be possible. Intravenous infusion of HI lowered blood glucose levels persistently for two weeks, providing a comparator model for use in two-week repeated-dose toxicity studies with new long-acting insulin analogues, which allows group housing, and thereby increasing animal welfare compared with an external infusion model.

Treatment of Spasticity with Baclofen Pump Implantation: A Clinical Prospective Study.

Background Data : The use of an implantable infusion pump for the treatment of spasticity is to provide the patient with lower dose that the patient is taking at the present time, and this small dose will be given in a steady fashion in the form of drip irrigation. The drip irrigation is through a small plastic catheter and in minute amounts continuously. Objective : to assess the efficiency of Baclofen pump implantation in patients with spasticity. Methods : This is a clinical prospective study of 20 patients with an implanted device of Intra thecal Infusion pump to treat cerebral and spinal spasticity (12 male age from 12 to 72 years, 8 female age from7 to 60 years) operated in the department of neurosurgery, Neurosciences hospital, Baghdad, Iraq, from October 2011 to December 2012.We evaluated the Presenting symptoms and sings before the operation and measured the outcome postoperatively. Results : The incidence of complications in ITB surgeries was 15% (3 of 20 patients) all of them were male. Satisfactory results was 90% (18 patients of 20), more obvious in pediatric age group (improvement in spasticity’s scale the postoperative complications were recorded are early emptiness of the infusion pump (withdrawal symptoms) The most common drawback that the patient had been seen in our practice is unavailability of the in our institutes nor in the private sectors and it is very expensive indeed and made a burden on their family. Conclusions : ITB is an excellent method of treating spastic CP generalized secondary dystonic CP, and patients with spinal cause of Spasticity (trauma, multiple sclerosis), with few complications.

An adjustable flow restrictor for implantable infusion pumps based on porous ceramics.

This paper describes an adjustable flow restrictor for use in gas-driven implantable infusion pumps, which is based on the resistance of a flow through a porous ceramic material. The flow inside the walls of a ceramic tube can be adjusted between 270 nl/min and 1260 nl/min by changing the flow path length in the ceramic over a distance of 14 mm. The long-term stability of the flow restrictor has been analyzed. A drift of -8% from the nominal value was observed, which lies within the required tolerance of ±10% after 30 days. The average time needed to change the flow rate is 40 s. In addition, the maximum adjustment time was 110 s, which also lies within the specification.

An experimental setup for traceable measurement and calibration of liquid flow rates down to 5 nl/min.

This work presents the improvements of an experimental setup for measuring ultra-low flow rates down to 5 nl/min. The system uses a telecentric CCD imaging system mounted on a high-precision, computer-controlled linear stage to track a moving liquid meniscus inside a glass capillary. Compared to the original setup, the lowest attainable expanded uncertainty at any flow rate has been reduced from 5.4% to 2%. In addition, the conformity with specification of three commercial micro-fluidic devices was evaluated using the new setup: one syringe pump, one implantable infusion pump and one thermal flow sensor. The flow sensor and the implantable infusion pump met the compliance criteria (coverage probability 95%). The syringe pump however, failed to meet the specifications at 5 nl/min and 10 nl/min. No assessment could be made at higher flow rates.

Onset Time and Durability of Huntingtin Suppression in Rhesus Putamen After Direct Infusion of Antihuntingtin siRNA.

One possible treatment for Huntington's disease involves direct infusion of a small, interfering RNA (siRNA) designed to reduce huntingtin expression into brain tissue from a chronically implanted programmable pump. Here, we studied the suppression of huntingtin mRNA achievable with short infusion times, and investigated how long suppression may persist after infusion ceases. Rhesus monkeys received 3 days of infusion of Magnevist into the putamen to confirm catheter patency and fluid distribution. After a 1-week washout period, monkeys received radiolabeled siRNA targeting huntingtin. After 1 or 3 days of siRNA delivery, monkeys were either terminated, or their pumps were shut off and they were terminated 10 or 24 days later. Results indicate that the onset of huntingtin mRNA suppression in the rhesus putamen occurs rapidly, achieving a plateau throughout the putamen within 4 days. Conversely, loss of huntingtin suppression progresses slowly, persisting an estimated 27–39 days in the putamen and surrounding white matter. These findings indicate the rapid onset and durability of siRNA-mediated target gene suppression observed in other organs also occurs in the brain, and support the use of episodic delivery of siRNA into the brain for treatment of Huntington's disease and possibly other neurodegenerative diseases.

Intravenous Treprostinil Delivered by the Implantable Pump Lenus Pro®: A Innovative “Surgical” Approach to Management of PAH

Purpose Continuous application of parenteral prostanoids with external pump systems is associated with frequent side effects such as infusion site pain with subcutaneous (s.c.) and rare but possibly life-threatening catheter related infections with intravenous (i.v.) administration. Lenus Pro ® implantable infusion pump was developed to overcome the drawbacks of s.c. administration. Methods and Materials Between September 2010 and October 2012 20 patients underwent implantation at our center. All patients had experienced significant clinical benefits with s.c. Treprostinil but reported serious site pain. All implantations were performed under general anesthesia. Preoperatively single-shot antibiotic prophylaxis was given. After a catheter was placed in the subclavian or cephalic vein, the pump pocket was prepared in the abdominal wall. Lenus Pro® pump was filled intraoperatively, placed in the pump pocket and fixed to the fascia. A catheter was tunneled under the breast tissue and connected with the central venous access by means of a titan connector. No intraoperative complications occurred; postoperatively three patients developed mild seroma. During follow-up, no other complications were observed. More than 300 refill procedures have been performed without any complications. Control of the reflow volume at every refill procedure revealed accurate and constant flow rate of Lenus Pro ® in all patients. Results Parenteral prostanoids are a cornerstone in the treatment of PAH. I.v. Treprostinil administered by Lenus Pro® was safe and effective in our study population, during more than 330 patient-months of treatment there were no pump or catheter related complications, especially no infections. No refill complications were observed. The absence of infusion related side effects is associated with an increase in quality of life, filling intervals of 28 days ensure optimal patient management and compliance. Conclusions We consider this new treatment option a milestone achievement in prostanoid therapy and management of PA.