Portable Pump Research Articles

Insulinothérapie par pompe à insuline : autosurveillance glycémique continue ou traditionnelle ?

Use of portable pumps is increasing to achieve intensive insulin treatment. Beside unpredictable insulin absorption and insufficient reactivity to changes of insulin flow rate due to the subcutaneous route, this therapy is however limited by the lack of information on blood glucose level provided by self-blood glucose monitoring. Thus, patient interpretation only leads to speculative adaptation of pump flow rate. The lack of alert toward the risk of hypoglycemia or hyperglycemic ketogenic deviations can lead to the occurrence of deleterious metabolic distorsions, among which severe hypoglycemia stands in first rank. Starting experiences of continuous recording of interstitial glucose level by portable systems using glucose-oxidase allow on short time durations the identification of daily periods of poor metabolic control. Retrospective availability of information gives the possibility of more adequate treatment adaptations than conventional capillary blood glucose monitoring, but does not allow immediate prevention of metabolic events. Only devices providing real time or near-real time information to the patient can fulfill this function. However, the absence of tight parallelism between variations of interstitial and blood glucose levels may lead to erroneous decisions. A true continuous real time information on blood glucose level on long-term seems only expectable from implantable glucose sensors. Still under investigation, these systems should be able to insure vigilance toward the risk of hypo- and hyperglycemia on weekly or monthly periods. Initially used as complementary to capillary self-monitoring, their reliability should allow their use as substitutes for conventional monitoring, except for measurements aimed at signal calibration. Pump control by the sensor signal is conceivable if it corresponds to a direct, continuous, real time measurement of blood glucose, and subject to a simultaneous improvement of insulin infusion modes.

Quelação oral de ferro na Beta-Talassemia

A quelação do ferro com deferroxamina (DFO) melhorou dramaticamente o prognóstico de pacientes com beta talassemia. A DFO reduz os estoques de ferro, bem como a morbidade e mortalidade destes pacientes. No entanto, a necessidade de infusões parenterais prolongadas estimulou a busca por novos quelantes. Deferiprone (DP) é o único quelante oral em uso clínico e já avaliado em estudos clínicos. A terapia combinada com DP e DFO surgiu como alternativa para pacientes talassêmicos. Ela tem o potencial de minimizar os efeitos adversos, aumentar a adesão e a eficácia, e, talvez, atingir compartimentos distintos de ferro no organismo. A disponibilização de novos quelantes e métodos de avaliação do ferro no organismo poderá permitir a individualização do tratamento quelante.

Delivery rate accuracy of portable, bolus-capable infusion pumps used for patient-controlled continuous regional analgesia

Background and Objectives: Portable patient-controlled pumps used for perineural local anesthetic infusion appear to be gaining acceptance and are used for an increasing number of medically unsupervised ambulatory patients. The infusion rate accuracy and reliability of these pumps, which allow patient-controlled boluses of potentially toxic medication, has not been independently investigated. We performed this laboratory study to define the flow-rate accuracy, reliability, and profiles of various portable bolus-capable infusion pumps and varied several factors that may influence pump performance. Methods: Using a computer/scale combination, 4 electronic pumps were tested with 1 and 2 sets of batteries over 100 hours. One elastomeric pump was tested with its flow-regulator at room temperature (20°C to 24°C), skin temperature (32°C), and increased temperature (36°C). The elastomeric pump was also tested by varying the height of the pump relative to the distal end of the catheter. Results: Infusion rate accuracy differed significantly among the pumps, exhibiting flow rates within ±15% of their expected rate for 29% to 100% of their infusion duration. Changing the batteries after 50 hours affected the profile of 1 of the 4 electronic pumps. For the elastomeric pump, an increase in temperature significantly increased the infusion rate. An increase or decrease in pump-to-scale height significantly increased or decreased the infusion rate, respectively. Conclusions: These results suggest that factors such as flow-rate accuracy and consistency, infusion profile, and temperature sensitivity should be taken into consideration when choosing a portable infusion pump for local anesthetic administration. Reg Anesth Pain Med 2003;28:17-23.

Experiencia de 10 años en el tratamiento con epoprostenol en perfusión intravenosa continua en hipertensión pulmonar arterial grave

Primary pulmonary hypertension and its associated forms is a progressive and often fatal disease, the course of which has been favourably modified by prostacyclin therapy in the last decade. The aim of this study is to analize retrospectively the efficacy of continuous intravenous epoprostenol (synthetic prostacyclin) therapy in pulmonary arterial hypertension, and to compare it with conventional therapy (anticoagulants, digoxin and diuretics). Between 1990-2000, 31 patients with severe precapillary pulmonary hypertension in functional class III or IV went on continuous intravenous epoprostenol therapy, administered by a portable infusion pump through a Hickman catheter. We compared their survival with a group of 16 patients treated with conventional therapy alone. Time of follow-up was 33.25 months in the prostacyclin group and 20 months in the conventional group. The one- three- and five- year survival rates were 86%, 50% and 38% respectively for patients treated with epoprostenol compared with 40%, 40% and 8% survival rates at idetical periods for patients treated conventionally (p = 0,02). Functional class and the mean distance walked in the 6 minutes test were improved in patients treated with prostacyclin (p < 0,01). Serious complications attributable to the delivery system included 3 deaths, mainly due to infection. Continuous intravenous epoprostenol therapy improves survival and exercise capacity in patients with severe pulmonary arterial hypertension despite potentially serious complications attributable to the delivery system.

Sampling of Highly Volatile Accelerants at the Fire Scene

ABSTRACTHighly volatile accelerants such as alcohols and low molecular weight organic solvents diffuse in the air rather than remain in the fire debris at a fire scene. Therefore, these components are not effectively recovered by sampling methods used to analyze the debris recovered from the fire scene. This study examined the effectiveness of air sampling at the fire scene using a portable air pump to collect highly volatile ignitable liquids used as accelerants. This was done by comparing the air sampling method with dynamic headspace sampling and solid phase microextraction (SPME) methods, which are widely used for isolation and sampling of fire debris. Air sampling was performed by adsorption of accelerants on a stainless tube filled with Tenax TA and Carbopack B. The results showed that highly volatile components were more efficiently collected through air sampling when compared with either dynamic headspace or SPME.

Randomized Clinical Trial of Postoperative Subfascial Infusion with Bupivacaine following Ambulatory Open Mesh Repair of Inguinal Hernia

Background: Wound pain remains the commonest problem after ambulatory open repair of inguinal hernia. Postoperative subfascial infusion of the wound with bupivacaine extends local analgesia at home and may achieve superior analgesia compared with oral analgesics alone. The objective of the present trial was to evaluate the efficacy of postoperative subfascial infusion of the wound with 0.5% bupicavaine at 2 ml per hour for 48 h after operation. Methods: Forty-four patients who underwent ambulatory open tension-free mesh hernioplasties were randomized to two arms of treatment. The pump group had an infusion pump containing 100 ml 0.5% bupivacaine being placed between the external oblique aponeurosis and the Prolene mesh, whereas the nonpump group was treated with oral analgesics alone. Assuming that an observed difference of 2.0 existed between the mean pain scores of the two groups, the estimated sample size would be at least 20 patients in each group. Results: Postoperative pain scores at rest and on coughing were significantly lower in the pump group than in the nonpump group on days 0 and 1 after surgery (p < 0.01). Before being discharged, none of the pump group patients requested analgesics, but 6 patients of the nonpump group required analgesic supplement (p = 0.025). Ten patients (50%) of the pump group experienced no pain during the period of bupivacaine infusion. Recovery variables, including time taken to resume ambulation and micturition, were comparable between the two groups. The pump and nonpump group patients returned to their normal activities after a median of 3 and 4 days, respectively (p = 0.217). The postoperative morbidity rates of the two groups were similar. Conclusion: Postoperative subfascial infusion of the wound with 0.5% bupivacaine achieved superior analgesia compared with oral analgesics alone. Portable infusion pump is a safe technique to continue local analgesia at home after ambulatory open repair of inguinal hernia. The drawbacks of the ON-Q Pain Management System included its high cost and frequent seepage of blood-stained anesthetic fluid into the wound dressing.

Development of a dog microdialysis model for determining synovial fluid pharmacokinetics of anti-arthritis compounds exemplified by methotrexate.

The purpose of this study was to develop and validate an animal model of drug disposition in synovial fluid (SF) by comparing microdialysis with arthrocentesis using the anti-arthritic drug methotrexate (MTX). Microdialysis probes were calibrated in vitro with the no net flux method using dog synovial fluid. The probes were implanted surgically into the stifle joint space of four dogs and were dialyzed overnight using a portable microinfusion pump. The membrane integrity of the probes was monitored by retrodialysis using an internal standard. After an intravenous bolus of 2.5 mg/kg of MTX, unbound concentrations in synovial fluid, as well as total plasma concentrations, were measured by liquid chromatography tandam mass spectrometer (LC/MS/MS) in samples collected from 0 to 48 h postdose. The probe membrane remained intact at least 48 h after implantation. The mean probe recovery and unbound fraction of MTX in SF were 46.8% and 44.8%, respectively. The unbound fraction of MTX was 44% in synovial fluid. MTX penetrated into the joint space rapidly, with maximal concentrations of 6.6 microM reached at approximately 1 h postdose. The unbound MTX area under the curve in SF was approximately 40% of the total area under the curve in plasma. These data agree well with the previous data obtained for MTX using arthrocentesis. In contrast with arthrocentesis, microdialysis enables the collection of multiple serial SF samples from individual animals with minimal trauma and potential blood contamination. This animal model should prove valuable for studying the disposition of new antiarthritis compounds or biomarkers in SF.

Ambulatory perineural local anesthetic infusion

Single-injection regional nerve blocks generally are limited in providing postoperative analgesia by their duration of 12 to 16 hours or less. The use of a perineural catheter to infuse local anesthetic allows for postoperative analgesia after the initial regional blockade has resolved. The relatively recent introduction of small, portable infusion pumps has allowed this technique to be used in the ambulatory setting. Although this form of analgesia offers significant improvements in pain control after many procedures, multiple factors such as patient education and close follow-up evaluation must be accounted for to provide safe and effective continuous nerve blocks at home. This article reviews important issues related specifically to ambulatory perineural local anesthetic infusion, including indications, exclusion criteria, issues of catheter placement, patient education, discharge criteria, patient follow-up, potential complications, documentation, catheter removal, and infusion pump selection. Copyright 2003, Elsevier Science (USA). All rights reserved.

Therapy for primary pulmonary hypertension.

Therapy for primary pulmonary hypertension.

Implantable closed-loop glucose-sensing and insulin delivery: the future for insulin pump therapy.

Although subcutaneous insulin infusion from portable pumps is the current optimal therapy for type 1 diabetic patients, implantable pumps using the intraperitoneal route allow increased blood glucose stability and lowered incidence of severe hypoglycemia. Subcutaneously implanted enzymatic glucose sensors provide continuous interstitial glucose monitoring, but this may differ from the real-time blood glucose levels. Preliminary investigations of intravascular enzymatic sensors demonstrate their clinical acceptability and accuracy and the possibility of developing closed-loop insulin delivery by combination with implantable pumps.

Advances in regional anesthesia for outpatients

This review will bring to the reader's attention recent developments in the literature regarding regional anesthesia in the outpatient setting, and allow the reader to evaluate whether these developments are appropriate for inclusion in clinical practice. The most stimulating developments in the area of regional anesthesia for outpatients revolve around the use of continuous analgesic therapy for outpatients after discharge. This is reflected in recent publications describing the use of continuous catheters for peripheral nerve blockade using portable pumps to provide 48-72 h of postoperative analgesia. These devices have raised the hope of opioid-free pain relief for virtually the entire duration of postsurgical pain in the outpatient setting. There are also increasing numbers of suggestions on ways to improve the quality of spinal anesthesia in the outpatient setting, particularly by using lower doses of lidocaine to reduce the problem of transient neurologic symptoms after spinal blockade. Several authors have investigated the cost implications of regional techniques in the outpatient setting, and have concluded that they are very competitive with the general anesthetic techniques that are frequently employed. Recent publications suggest additional ways to add regional anesthesia techniques to outpatient surgical practice, particularly with the promise of extensive postoperative pain relief for the ambulatory surgery patient.

Night‐time only insulin pump therapy in young children with type 1 diabetes mellitus

AbstractContinuous subcutaneous insulin infusion via portable pumps has been developed to improve metabolic control in patients with diabetes mellitus by imitating physiological insulin secretion but is generally not recommended for children below the age of 12–14 years. Since especially young children with dawn phenomenon would benefit from continuous insulin application, we started night‐time only insulin pump therapy in four children aged 4–11 years. We retrospectively analysed these patients in regard to metabolic control and satisfaction with therapy. There were no ketoacidotic hyperglycemias or technical defects and the rate of severe hypoglycemia rose slightly from 0.0 to 0.063 per patient and year. Three out of four families reported high satisfaction with the new therapy and an increase in quality of life. Mean HbA1c fell from 7.2% to 6.6%, then rose again.We conclude that night‐time only insulin pump therapy might be a safe way of controlling dawn phenomenon in young children with type 1 diabetes mellitus. Copyright © 2002 John Wiley &amp; Sons, Ltd.

Determination of carbon disulfide at the workplace by sampling on charcoal tubes--problems and solutions.

The aim of the study was to check the reliability and comparability of different analytical methods for ambient monitoring of carbon disulfide (CS2). A stationary sampling system, consisting of a charcoal sampling tube and pump, and two personal sampling systems, consisting of a charcoal sampling tube and a portable pump and of a diffusive charcoal sampler have been compared. The limits of quantification, within-series precision, between-series precision, recovery, and comparability of the methods were investigated. For passive sampling the recovery was determined by three different techniques. For a sampling time of 6 hours the limit of quantification was 0.2 ppm for the personal sampling and 0.01 ppm for the stationary sampling system. The within-series precision was between 5 and 8%. For personal sampling the between-series precision was between 9 and 12% using a passive sampler. The recovery ranged between 45 and 85% depending on the quotient of eluent volume and charcoal mass. The comparison of the two personal sampling methods in a field study using linear regression demonstrated with statistical certainty an excellent concordance of the methods. The study shows that particularly the method for determining air levels of carbon disulfide by passive sampling is associated with high systematic errors. If these errors are unknown or ignored they will result in highly underestimated exposure data for carbon disulfide.

5 questions-and answers-about negative pressure wound therapy.

Q: What is negative pressure wound therapy?A: Negative pressure wound therapy (NPWT) is an adjunctive wound treatment that involves the application of a controlled level of subatmospheric pressure to a wound at 50 mm Hg to 175 mm Hg. 1 Generated by a portable programmable pump, the suction effect is

High-Dose 5-Fluorouracil / Folinic Acid in Combination with Three-Weekly Mitomycin C in the Treatment of Advanced Gastric Cancer. A Phase II Study

Background: The 24-hour continuous infusion of 5-fluorouracil (5-FU) and folinic acid (FA) as part of several new multidrug chemotherapy regimens in advanced gastric cancer (AGC) has shown to be effective, with low toxicity. In a previous phase II study with 3-weekly bolus 5-FU, FA and mitomycin C (MMC) we found a low toxicity rate and response rates comparable to those of regimens such as ELF, FAM or FAMTX, and a promising median overall survival. In order to improve this MMC-dependent schedule we initiated a phase II study with high-dose 5-FU/FA and 3-weekly bolus MMC. Patients and Methods: From February, 1998 to September, 2000 we recruited 33 patients with AGC to receive weekly 24-hour 5-FU 2,600 mg/m² preceded by 2-hour FA 500 mg/m² for 6 weeks, followed by a 2-week rest period. Bolus MMC 10 mg/m² was added in 3-weekly intervals. Treatment given on an outpatient basis, using portable pump systems, was repeated on day 57. Patients’ characteristics were: male/female ratio 20/13; median age 57 (27–75) years; median WHO status 1 (0–2). 18 patients had a primary AGC, and 15 showed a relapsed AGC. Median follow-up was 11.8 months (range of those surviving: 2.7–11.8 months). Results: 32 patients were evaluable for response – complete remission 9.1% (n = 3), partial remission 45.5% (n = 15), no change 27.3% (n = 9), progressive disease 15.1% (n = 5). Median overall survival time was 10.2 months [95% confidence interval (CI): 8.7–11.6], and median progression-free survival time was 7.6 months (95% CI: 4.4–10.9). The worst toxicities (%) observed were (CTC-NCI 1/2/3): leukopenia 45.5/18.2/6.1, thrombocytopenia 33.3/9.1/6.1, vomitus 24.2/9.1/0, diarrhea 36.4/6.1/3.0, stomatitis 18.2/9.1/0, hand-foot syndrome 12.1/0/0. Two patients developed hemolytic-uremic syndrome (HUS). Conclusions: High-dose 5-FU/FA/MMC is an effective and well-tolerated outpatient regimen for AGC (objective response rate 54.6%). It may serve as an alternative to cisplatin-containing regimens; however, it has to be considered that possibly HUS may occur.

Chemotherapy with cisplatin and 5-fluorouracil chronomodulated infusion in locally advanced or metastatic/recurrent carcinoma of the cervix.

The purpose of this study was to review our experience with the combination of circadian chronomodulated 5-fluorouracil infusion in association with cisplatin in patients with locally advanced or metastatic cancer of the cervix in order to assess the activity and tolerability of the combination. Twenty patients with locally advanced disease and 21 patients with metastatic or recurrent disease were treated from January 1995 to May 1999. 5-fluorouracil (600 mg/m2, days 1 to 5) was administered by a continuous circadian-shaped infusion employing an external programmable portable pump; cisplatinum (20 mg/m2) was infused days 1 through 5 i.v. over a 2-hr period. Response to treatment was evaluated after 3 and 6 cycles of therapy. Patients with locally advanced disease who achieved a clinical shrinkage of their tumor or were at least stable were submitted to surgery; pelvic radiotherapy was administered to patients with disease progression. Seven patients with locally advanced disease achieved a partial clinical response (overall response, 35%; 95% CI, 15.4-59.2), and 12 of 20 patients were submitted to surgery. Median progression-free and overall survival were 17 months and 36 months, respectively. Objective responses were observed in 9 of 21 patients with metastatic/recurrent disease (7 partial plus 2 minor responses: overall response 43%; 95% CI, 21.8-65.9). Median time to progression and overall survival were 5 and 17 months, respectively. Cisplatinum plus 5-fluorouracil chronomodulated infusion showed a moderate but definite activity and was well tolerated in both groups of patients. In consideration of clinical results comparable to more toxic and expensive regimens reported in the literature, the combination appears to be a reasonable option especially for women with metastatic/recurrent cervical carcinoma and a promising treatment in combination with definitive radiotherapy in patients with locally advanced disease.

PRELIMINARY ASSESSMENT OF ATMOSPHERIC METHYLCYCLOPENTADIENYL MANGANESE TRICARBONYL AND PARTICULATE MANGANESE IN SELECTED URBAN SITES

Methylcyclopentadienyl manganese tricarbonyl (MMT: C 9 H 7 MnO 3 ) is an organometallic additive that has been used since 1976 as an octane enhancer in Canadian unleaded gasoline. Very few studies have determined its atmospheric concentrations and only one study offers recent data on its ambient level. This preliminary study aims to assess atmospheric concentrations of MMT and respirable and total Mn (Mn R and Mn T ) in selected sites, at two underground car parks and one gasoline station, related to high levels of automobile traffic. It is also an investigation of the applicability of the current analytical method. In total, 34 air samples were collected using a Gil-Air portable pump during 4 consecutive days and then were analyzed by neutron activation analysis. The concentrations vary between 40 and 104 ng/m 3 for Mn R , 146 and 204 ng/m 3 for Mn T , and 6 and 128 ng/m 3 for MMT (including ultrafine particulates, Mn UF ). Of the 12 Mn R results, 7 showed concentrations greater than the U.S. EPA reference concentration (RfC = 50 ng/m 3 ). The ratios of Mn R to Mn T varied from 0.20 to 0.65 with a mean of 0.38. The results for MMT and Mn UF raise serious doubts about the specificity of the sampling and chemical analysis methodology proposed by the Occupational Safety and Health Administration (OSHA) for MMT in air.

A portable mechanical pump providing over four days of patient-controlled analgesia by perineural infusion at home

Background and Objectives: Local anesthetics infused via perineural catheters postoperatively decrease opioid use and side effects while improving analgesia. However, the infusion pumps described for outpatients have been limited by several factors, including the following: limited local anesthetic reservoir volume, fixed infusion rate, and inability to provide patient-controlled doses of local anesthetic in combination with a continuous infusion. We describe a patient undergoing open rotator cuff repair who was discharged home with an interscalene perineural catheter and a mechanical infusion pump that allowed a variable rate of continuous infusion, as well as patient-controlled boluses of local anesthetic for over 4 days. Case Report: A 77-year-old woman, who had previously required a 3-day hospital admission for acute postoperative pain following an open repair of her left rotator cuff, presented for an open repair of her contralateral rotator cuff. Preoperatively she received an interscalene block and perineural catheter. After the procedure she was discharged home with a portable pump that infused ropivacaine continuously at a rate of 6 mL/h and allowed a 2-mL patient-controlled bolus every 20 minutes (550-mL reservoir). The basal infusion was decreased, as tolerated, by having the patient reprogram the pump with instructions given over the telephone. Without the use of any oral opioids, the patient scored her surgical pain 0 to 1 (on a scale of 0 to 10) while at rest and 2 to 3 for 2 physical therapy sessions during which she used the bolus function to reinforce her analgesia. After 98 hours of infusion, the patient's husband removed the catheter with instructions given over the telephone, and her subsequent surgical pain was treated with oral opioids. Conclusion: Continuous, perineural local anesthetic infusions are possible on an ambulatory basis for multiple days using a portable, programmable pump that provides a variable basal infusion rate, patient-controlled boluses, and a large anesthetic reservoir. Reg Anesth Pain Med 2002;27:100-104.

Continuous subcutaneous insulin infusion in the treatment of children and adolescents with type 1 diabetes mellitus.

Continuous subcutaneous insulin infusion (CSII) with a portable insulin pump has been used for several years in the treatment of adult patients with diabetes mellitus (DM). This treatment, however, has rarely been utilised in children and adolescents. We studied the use of CSII in 16 children and adolescents with type 1 DM at Tampere and Kuopio University Hospitals between 1992 and 1997. The longest treatment periods are more than 4 years. The reasons for switching to CSII treatment and the goals achieved were evaluated. Glycaemic control before and during CSII treatment and the occurrence of hypoglycaemia and ketoacidosis were analysed. Compared with conventional insulin treatment, improved glycaemic control and a reduced frequency of hypoglycaemic events were achieved with CSII in those with particularly poor initial metabolic control (HbA1c >10.0%). The overall satisfaction with pump therapy was high in both patients and their families. According to our experience, CSII may be of benefit, especially in young infants with type 1 DM, but also in affected adolescents with unacceptable glycaemic control.

The airborne 1,3-butadiene concentrations in rubber and plastic processing plants

Environment pollution by 1,3-butadiene had considerably increased in Japan. The main cause of the pollution is the automotive exhaust gas, and leaks from factories, smoking, and burning of rubber and plastic products are considered to be minor sources. The object of this study was to determine the contamination levels of airborne 1,3-butadiene in factories processing rubber and plastics containing 1,3-butadiene. The concentrations of airborne 1,3-butadiene were measured in 21 plants (10 rubber processing plants and 11 plastics processing plants) in Osaka. 1,3-Butadiene in air was collected for 10 minutes with a charcoal tube and a portable small pump adjusted to a 250 ml/min flow rate. In each plant, indoor air samples at five points and an outdoor air sample at one point outside the plant were collected. The samples were subjected to gas chromatography/mass spectrometry after thermal desorption from the charcoal. The concentrations of airborne 1,3-butadiene in the rubber processing plants and the plastics processing plants were 0.14-2.20 micrograms/m3 (geometric mean: 0.48 microgram/m3) and 0.23-4.51 micrograms/m3 (geometric mean: 0.80 microgram/m3), respectively. In all plants examined, indoor 1,3-butadiene concentrations were higher than the outdoor concentrations around the plants. Therefore, 1,3-butadiene was considered to arise from the processing of rubber or plastics, but the indoor 1,3-butadiene concentrations were much lower than the PEL-TWA (1 ppm = 2.21 mg/m3) of OSHA and the TLV-TWA (2 ppm) of ACGIH. The concentrations in the plants with closed room conditions without ventilation were higher than the concentrations in the other plants. It was suggested that ventilation affected the 1,3-butadiene concentration in the plants.