Safety and performance of intravenous pumps and syringe drivers in hyperbaric environments.

INTRODUCTION: Critically ill patients require continuation of their care when receiving hyperbaric oxygen treatment. This care may be facilitated via portable electrically powered devices such as intravenous (IV) infusion pumps and syringe drivers, which may create risks in the absence of a comprehensive safety evaluation. We reviewed published safety data for IV infusion pumps and powered syringe drivers in hyperbaric environments and compared the evaluation processes to key requirements documented in safety standards and guidelines. METHODS: A systematic literature review was undertaken to identify English language papers published in the last 15 years, describing the safety evaluations of IV pumps and/or syringe drivers for use in hyperbaric environments. Papers were critically assessed in relation to the requirements of international standards and safety recommendations. RESULTS: Eight studies of IV infusion devices were identified. There were deficiencies in the published safety evaluations of IV pumps for hyperbaric use. Despite a simple, published process for evaluating new devices, and available guidelines for fire safety, only two devices had comprehensive safety assessments. Most studies focused only on whether the device functioned normally under pressure and did not consider implosion/explosion risk, fire safety, toxicity, oxygen compatibility or risk of pressure damage. CONCLUSIONS: Intravenous infusion (and other electrically powered) devices require comprehensive assessment before use under hyperbaric conditions. This would be enhanced by a publicly accessible database hosting the risk assessments. Facilities should conduct their own assessments specific to their environment and practices.

Hepatic arterial infusion pump chemotherapy combined with systemic therapy for patients with advanced colorectal liver metastases: Outcomes in a newly established program.

BACKGROUND AND OBJECTIVES: Colorectal liver metastasis (CRLM) is a leading cause of morbidity and mortality in patients with colorectal cancer. Hepatic arterial infusion (HAI) chemotherapy has been demonstrated to improve survival in patients with resected CRLM and to facilitate conversion of technically unresectable disease. METHODS: Between 2016 and 2018, n = 22 HAI pumps were placed for CRLM. All patients received systemic chemotherapy concurrently with HAI floxuridine/dexamethasone. Overall survival (OS) and progression-free survival (PFS) were assessed using the Kaplan-Meier method. RESULTS: HAI pumps were placed in seven patients with completely resected CRLM and 15 patients with unresectable disease. Twenty-one patients received HAI floxuridine with a median of 5 total HAI cycles (interquartile range: 4-7). Biliary sclerosis was the most common HAI-related complication (n = 5, 24%). Of the 13 patients treated to convert unresectable CRLM, 3 (23%) underwent hepatic resection with curative intent after a median of 7 HAI cycles (range: 4-10). For all HAI patients, the mean OS was 26.7 months from CRLM diagnosis, while the median PFS and hepatic PFS from pump placement were 9 and 13 months, respectively. CONCLUSION: Concomitant HAI and systemic therapy can be utilized at multidisciplinary programs for patients with advanced CRLM, both in the adjuvant setting and to facilitate conversion of unresectable disease.

Comparison of Nausea and Vomiting Associated With Amino Acid Formulations Coinfused With Peptide Receptor Radionuclide Therapy: Commercial Parenteral Nutrition Formulas Versus Compounded Arginine/Lysine.

OBJECTIVES: Positively charged amino acids (AA) such as arginine/lysine are coinfused with radiolabeled somatostatin analogs to reduce rates of nephrotoxicity. In the phase 3 NETTER-1 trial, commercial AA formulations were used in association with 177Lu-DOTA-0-Tyr3-Octreotate (DOTATATE). These formulations were also used in an early-access program (EAP) before regulatory approval of 177Lu-DOTATATE. Our program transitioned to compounded l-arginine 2.5%/l-lysine 2.5% in 0.9% NaCl after commercial approval of 177Lu-DOTATATE. We sought to compare rates of nausea/vomiting with arginine/lysine versus commercial parenteral AA formulations. METHODS: Rates of nausea/vomiting of all 20 EAP patients who received commercial AAs (15% Clinisol) were compared with the first 29 patients to receive 177Lu-DOTATATE after commercial approval and coinfused with arginine/lysine. Other parameters reviewed included infusion rates, need for PRN nausea medications, and other toxicities. RESULTS: Seventeen percent of patients who received compounded arginine/lysine experienced nausea, compared with 100% of patients in the EAP group (P < 0.0001). Infusion-related reactions occurred in 3% of the arginine/lysine cohort versus 35% in the EAP group. Infusion durations were substantially shorter in the arginine/lysine cohort (reduced by 61%). CONCLUSIONS: Coinfusions of arginine/lysine with radiolabeled somatostatin analogs result in substantially lower rates of nausea/vomiting compared with commercial AA formulations designed for parenteral nutrition.

Strategies for intra-amniotic administration of fetal therapy in a rabbit model of intrauterine growth restriction.

Intrauterine growth restriction affects up to 10% of all pregnancies, leading to fetal programming with detrimental consequences for lifelong health. However, no therapeutic strategies have so far been effective to ameliorate these consequences. Our previous study has demonstrated that a single dose of nutrients administered into the amniotic cavity, bypassing the often dysfunctional placenta via intra-amniotic administration, improved survival at birth but not birthweight in an intrauterine growth restriction rabbit model. The aim of this study was to further develop an effective strategy for intra-amniotic fetal therapy in an animal model. Intrauterine growth restriction was induced by selective ligation of uteroplacental vessels on one uterine horn of pregnant rabbits at gestational day 25, and fetuses were delivered by cesarean section on GD30. During the five days of intrauterine growth restriction development, three different methods of intra-amniotic administration were used: continuous intra-amniotic infusion by osmotic pump, multiple intra-amniotic injections, and single fetal intraperitoneal injection. Technical feasibility, capability to systematically reach the fetus, and survival and birthweight of the derived offspring were evaluated for each technique. Continuous intra-amniotic infusion by osmotic pump was not feasible owing to the high occurrence of catheter displacement and amnion rupture, while methods using two intra-amniotic injections and one fetal intraperitoneal injection were technically feasible but compromised fetal survival. Taking into account all the numerous factors affecting intra-amniotic fetal therapy in the intrauterine growth restriction rabbit model, we conclude that an optimal therapeutic strategy with low technical failure and positive fetal impact on both survival and birthweight still needs to be found.

Fadiga de alarmes em bombas de infusão no contexto pediátrico: revisão integrativa / Alarm fatigue in infusion pumps in the pediatric context: integrative review / Fatiga de alarma en bombas de infusión en el contexto pediátrico: revisión integrativa

Objetivo: identificar as causas da fadiga de alarmes em estudos de usabilidade de bomba de infusão em terapia intensiva pediátrica. Métodos: Realizou-se uma revisão integrativa nas bases de dados LILACS, SciELO, IBECS, SCOPUS e MEDLINE. Resultados: Foram identificadas 1.164 publicações e selecionados seis estudos primários que emergiram em duas temáticas: compreender as causas dos alarmes da bomba de infusão que constou: biblioteca de fármacos incompleta, limites absolutos e relativos rígidos, falta de protocolo de preparo e administração de medicação, período de férias dos funcionários; e as medidas que podem evitar a fadiga de seus alarmes.Conclusão:falhas na usabilidade de bombas de infusão aumentam os alarmes desnecessários que podem promovem sua fadiga. A utilização segura de bombas de infusão demanda uma equipe que monitore suas práticas e atue promovendo mudanças no contexto de trabalho

Objective: to identify the causes of alarm fatigue in studies of infusion pump usability in pediatric intensive care. Methods: an integrative review was carried out in the LILACS, SciELO, IBECS, SCOPUS and MEDLINE databases. Results: 1,164 publications were identified and six primary studies were selected that emerged in two themes: understanding the causes of the infusion pump alarms that consisted of: incomplete drug library, absolute and strict relative limits, lack of preparation protocol and medication administration, employee vacation period; and measures that can prevent fatigue from your alarms. Conclusion: the causes of alarm fatigue involve low user interaction with the equipment, inadequate work processes and low investment in preventive measures for its occurrence The safe use of infusion pumps requires a team to monitor their practices and act by promoting changes in the work context

Objetivo: identificar las causas de la fatiga de alarma en estudios de usabilidad de bombas de infusión en cuidados intensivos pediátricos. Métodos: se realizó una revisión integradora en las bases de datos LILACS, SciELO, IBECS, SCOPUS y MEDLINE. Resultados: se identificaron 1.164 publicaciones y se seleccionaron seis estudios primarios que surgieron en dos temas: comprender las causas de las alarmas de la bomba de infusión que consistían en: biblioteca de medicamentos incompleta, límites relativos absolutos y estrictos, falta de protocolo de preparación y administración de medicamentos, período de vacaciones de los empleados; y medidas que pueden prevenir la fatiga de sus alarmas. Conclusión: las causas de la fatiga de las alarmas involucran baja interacción del usuario con el equipo, procesos de trabajo inadecuados y baja inversión en medidas preventivas para su ocurrencia. El uso seguro de las bombas de infusión requiere que un equipo monitoree sus prácticas y actúe promoviendo cambios en el contexto de trabajo

L-carnitine infusion does not alleviate lipid-induced insulin resistance and metabolic inflexibility.

BACKGROUND: Low carnitine status may underlie the development of insulin resistance and metabolic inflexibility. Intravenous lipid infusion elevates plasma free fatty acid (FFA) concentration and is a model for simulating insulin resistance and metabolic inflexibility in healthy, insulin sensitive volunteers. Here, we hypothesized that co-infusion of L-carnitine may alleviate lipid-induced insulin resistance and metabolic inflexibility. METHODS: In a randomized crossover trial, eight young healthy volunteers underwent hyperinsulinemic-euglycemic clamps (40mU/m2/min) with simultaneous infusion of saline (CON), Intralipid (20%, 90mL/h) (LIPID), or Intralipid (20%, 90mL/h) combined with L-carnitine infusion (28mg/kg) (LIPID+CAR). Ten volunteers were randomized for the intervention arms (CON, LIPID and LIPID+CAR), but two dropped-out during the study. Therefore, eight volunteers participated in all three intervention arms and were included for analysis. RESULTS: L-carnitine infusion elevated plasma free carnitine availability and resulted in a more pronounced increase in plasma acetylcarnitine, short-, medium-, and long-chain acylcarnitines compared to lipid infusion, however no differences in skeletal muscle free carnitine or acetylcarnitine were found. Peripheral insulin sensitivity and metabolic flexibility were blunted upon lipid infusion compared to CON but L-carnitine infusion did not alleviate this. CONCLUSION: Acute L-carnitine infusion could not alleviated lipid-induced insulin resistance and metabolic inflexibility and did not alter skeletal muscle carnitine availability. Possibly, lipid-induced insulin resistance may also have affected carnitine uptake and may have blunted the insulin-induced carnitine storage in muscle. Future studies are needed to investigate this.

Optimizing circadian drug infusion schedules towards personalized cancer chronotherapy.

Precision medicine requires accurate technologies for drug administration and proper systems pharmacology approaches for patient data analysis. Here, plasma pharmacokinetics (PK) data of the OPTILIV trial in which cancer patients received oxaliplatin, 5-fluorouracil and irinotecan via chronomodulated schedules delivered by an infusion pump into the hepatic artery were mathematically investigated. A pump-to-patient model was designed in order to accurately represent the drug solution dynamics from the pump to the patient blood. It was connected to semi-mechanistic PK models to analyse inter-patient variability in PK parameters. Large time delays of up to 1h41 between the actual pump start and the time of drug detection in patient blood was predicted by the model and confirmed by PK data. Sudden delivery spike in the patient artery due to glucose rinse after drug administration accounted for up to 10.7% of the total drug dose. New model-guided delivery profiles were designed to precisely lead to the drug exposure intended by clinicians. Next, the complete mathematical framework achieved a very good fit to individual time-concentration PK profiles and concluded that inter-subject differences in PK parameters was the lowest for irinotecan, intermediate for oxaliplatin and the largest for 5-fluorouracil. Clustering patients according to their PK parameter values revealed patient subgroups for each drug in which inter-patient variability was largely decreased compared to that in the total population. This study provides a complete mathematical framework to optimize drug infusion pumps and inform on inter-patient PK variability, a step towards precise and personalized cancer chronotherapy.

Overcoming stability challenges during continuous intravenous administration of high-dose amoxicillin using portable elastomeric pumps.

While treatment of serious infectious diseases may require high-dose amoxicillin, continuous infusion may be limited by lack of knowledge regarding the chemical stability of the drug. Therefore, we have performed a comprehensive study so as to determine the chemical stability of high-dose amoxicillin solutions conducive to safe and effective continuous intravenous administration using portable elastomeric pumps. First, amoxicillin solubility in water was assessed within the range of 25 to 300 mg/mL. Then, amoxicillin solutions were prepared at different concentrations (25, 50, 125, 250 mg/mL) and stored in different conditions (5±2°C, 25±1°C, 30±1°C and 37±1°C) to investigate the influence of concentration and temperature on the chemical stability of amoxicillin. Finally, its stability was assessed under optimized conditions using a fully validated HPLC-UV stability-indicating method. Degradation products of amoxicillin were investigated by accurate mass determination using high-resolution mass spectrometry. Amoxicillin displayed limited water solubility requiring reconstitution at concentrations below or equal to 150 mg/mL. Amoxicillin degradation were time, temperature as well as concentration-dependent, resulting in short-term stability, in particular at high concentrations. Four degradation products of amoxicillin have been identified. Among them, amoxicilloic acid and diketopiperazine amoxicillin are at risk of allergic reaction and may accumulate in the patient. Optimized conditions allowing for continuous infusion of high-dose amoxicillin has been determined: amoxicillin should be reconstituted at 25 mg/mL and stored up to 12 hours at room temperature (22 ± 4°C) or up to 24 hours between 4 and 8°C.

Intermittent bolus versus continuous infusion techniques for local anesthetic delivery in peripheral and truncal nerve analgesia: the current state of evidence.

Manually delivered intermittent bolus (MIB) and programmable intermittent bolus (PIB), alternatives to continuous infusion (CI), involve administering a set volume of solution at a set interval of time. The benefits of intermittent bolus techniques in truncal and peripheral nerve blockade (TPNB) are unclear, and studies have largely demonstrated conflicting results. Using MEDLINE, Embase, Google Scholar, and the Cochrane Library, we conducted an evidenced-based review of published randomized controlled trials comparing intermittent bolus and CI methods in TPNB. In total, 13 randomized controlled trials were identified and evaluated. Outcomes data addressed in these studies included assessments of pain, opioid and local anesthetic consumption, patient satisfaction, adverse events, and physical therapy metrics. The overall quality of current evidence was found to be low given the small sample sizes, heterogeneity of data, and the variations in intermittent bolus techniques between studies. At this time, we found limited supportive data to endorse MIB or PIB over CI in TPNB. While unable to provide data-driven conclusions for local anesthetic delivery methods at this time, we propose that future studies and quantitative analysis between techniques should be on an anatomic, site-specific basis, with greater focus on evaluation of opioid use, adverse events, patient satisfaction, and rehabilitative metrics.

Avaliação microbiológica de superfícies em terapia intensiva: reflexões sobre as estratégias preventivas de infecções nosocomiais / Microbiological evaluation of surfaces in intensive care: thinking about nosocomial infection prevention strategies / Evaluación microbiológica de superficies en cuidados intensivos: reflexiones sobre las estrategias preventivas de infecciones nosocomiales

Objetivo: determinar o perfil microbiológico de bactérias isoladas e identificadas nos leitos e bombas infusoras na unidade de terapia intensiva de um hospital universitário do Estado do Rio de Janeiro. Método: foram coletadas nove amostras de grades das camas dos pacientes e oito de teclados de bomba infusora de uma unidade de terapia intensiva, em outubro de 2014, delimitando-se uma área de 100cm² como parâmetro para ambas as coletas. As amostras foram coletadas através de swabs estéreis que foram umedecidos e transportados em Carry & Blair. Os microrganismos foram isolados, classificados e depois testados em relação à resistência antimicrobiana. Resultados: o gênero Staphylococcus coagulase negativa foi o mais prevalente. Os testes de suscetibilidade a antimicrobianos apontaram alguns destes Staphylococci como multirresistentes. Conclusão: chama-se atenção para a necessidade de ampliação do debate multiprofissional sobre questões de segurança hospitalar, apresentando a educação permanente como um possível caminho de sucesso no controle das infecções.

Objective: to determine the microbiological profile of bacteria isolated and identified from beds and infusion pumps in the intensive care unit of a university hospital in Rio de Janeiro state. Method: nine samples were collected from patients' bed side rails and eight from infusion pump keypads in an intensive care unit in October 2014. An area of 100cm² was delimited as the sampling parameter. Samples were collected using sterile swabs, which were wetted and transported with Cary-Blair. The microorganisms were isolated, classified, and then tested for antimicrobial resistance. Results: coagulase-negative Staphylococcus was the most prevalent type. Antimicrobial susceptibility testing indicated some of these Staphylococci were multi-drug resistant. Conclusion: multi-professional discussion of hospital safety issues must be expanded, and continuing professional development emerges as one possible pathway to success in nosocomial infection control.

Objetivo: determinar el perfil microbiológico de bacterias aisladas e identificadas en las camas y las bombas de infusión en la unidad de terapia intensiva de un hospital universitario de Rio de Janeiro. Método: se recolectaron nueve muestras de rejas de camas de pacientes y ocho de paneles de las bombas de infusión de una unidad de terapia intensiva, en octubre de 2014, delimitandose un área de 100 cm2 como parámetro para ambas recolecciones. Se recolectaron las muestras a través de swabs estériles que fueron humedecidos y transportados en Carry y Blair. Los microorganismos fueron aislados, clasificados y después probados repecto a la resistencia antimicrobiana. Resultados: el género Staphylococcus coagulasa negativo fue el más prevalente. Las pruebas de susceptibilidad a antimicrobianos mostraron algunos Staphylococci como resistentes a múltiples fármacos. Conclusión: se señala la necesidad de ampliación del debate entre los profesionales de la salud, sobre cuestiones de seguridad hospitalaria, presentando la educación permanente como un posible camino de éxito en el control de las infecciones.

Rapid Push vs Pump-Infused Subcutaneous Immunoglobulin Treatment: a Randomized Crossover Study of Quality of Life in Primary Immunodeficiency Patients.

PURPOSE: Subcutaneous immunoglobulin replacement therapy (IgRT) may be administered once a week with a pump or every other day with a syringe (rapid push). The objective of the study was to compare the impact of pump and rapid push infusions on patient's life quality index (LQI). METHODS: This study was a randomized, crossover, multicenter, non-inferiority trial conducted in adults with primary immunodeficiency (PID) accustomed to weekly infusions at home by pump. Patients used pump or rapid push for 3 months each according to the randomized sequence. Main criterion was PID-LQI factor I (treatment interference). Non-inferiority ratio was set at 90%. RESULTS: Thirty patients entered the study; 28 completed the two periods. IgRT exposure was similar during each period. At the end of each period, mean LQI factor 1 was 87.0 (IC95% [80.3; 94.3]) and 77.80 (IC95% [71.5; 84.7]) for pump and rapid push, respectively. There was a slightly larger effect of rapid push on treatment interference than with pump so that the primary endpoint could not be met. No difference was found on other LQI components, satisfaction (TSQM), or quality of life (SF36v2). Eight patients declared to prefer rapid push while 19 others preferred pump. Of rapid push infusions, 67.2% led to local reactions vs 71.8% of pump infusions (p = 0.11) illustrating its good tolerance. Rapid push and pump infusions achieved similar trough IgG levels with similar incidence of infections. Rapid push saved 70% of administration cost when compared to pump. CONCLUSIONS: Since IgRT is a lifelong treatment in PID patients, individualization of treatment is of paramount importance. Rapid push is a new administration method in the physician's armamentarium which is preferred by some patients and is cost-effective. CLINICALTRIALS. GOV IDENTIFIER: NCT02180763 CLINICAL IMPLICATIONS: Self-administration of small volumes of immunoglobulins at home, every other day, using a syringe (rapid push) is a cost-effective alternative to administration of larger volumes by pump once a week. This study compared subcutaneous infusions of immunoglobulins either weekly via a pump or every other day via a syringe (rapid push). Rapid push is preferred by some patients and is cost-effective, therefore completing a physician's armamentarium.

Neuromodulation in Pediatrics: Case Series.

OBJECTIVES: Neuromodulation, particularly intrathecal drug delivery systems and spinal cord stimulators (SCSs), can be a valuable tool when treating chronic pain in adults. However, there is a paucity of literature with regard to its use in pediatrics. MATERIALS AND METHODS: We present a series of 14 children and adolescents with intractable pain who received a SCS or a pump for the intrathecal delivery of medications between 2010 and 2016 at our institution. RESULTS: During the study period, we placed 10 intrathecal pumps and 4 SCSs with an average age of 17 years old. Pain scores significantly improved after the implant (P<0.007) and function improved in 79% of patients. Opioid use was also significantly reduced. Three patients eventually had their device removed due to psychiatric comorbidities. Four patients had complications that were treated without further sequelae. CONCLUSIONS: Neuromodulation can offer important options in treating some pediatric chronic pain patients. In-depth knowledge of primary disease and strict patient selection in the context of the patient's social situation is vital to successful treatment.

Prolonged versus short infusion rates for intravenous magnesium sulfate administration in hematopoietic cell transplant patients.

PURPOSE: Hematopoietic cell transplant (HCT) recipients often require intravenous (IV) magnesium repletion due to poor dietary intake, gastrointestinal loss, and use of concomitant magnesium wasting medications. Prolonging the IV magnesium infusion rate has been postulated to reduce renal clearance and improve retention; however, limited evidence supports this hypothesis. METHODS: We reviewed autologous and allogeneic HCT recipients (n = 82) who received IV magnesium at our institution between 2014 and 2016: 41 patients received IV magnesium at a prolonged rate of 0.5 g/h and 41 patients at > 0.5 g/h (mean 2.07 g/h). Primary outcome was percent of days in which magnesium levels were in desired therapeutic range (2-2.7 mg/dL) during hospitalization. RESULTS: Baseline characteristics were similar between cohorts: no difference existed between groups in incidence of gastrointestinal graft-versus-host disease or the percentage of patients who received magnesium replacement in maintenance fluids, received concomitant oral magnesium supplementation, or received parenteral nutrition. Percent of days in desired therapeutic range was not different between groups (p = 0.3). No difference existed between groups with respect to total amount of IV magnesium repletion (22.5 vs. 21.4 g, p = 0.81) or number of days of IV replacement (7.2 vs. 6.2 days, p = 0.41). In terms of safety, there was no difference between groups with respect to incidence of hypomagnesemia or hypermagnesemia (p = 0.43 each). CONCLUSIONS: Overall, prolonging the infusion rate did not correlate with improved magnesium retention based on amount and frequency of magnesium repletion or attainment of goal levels in HCT patients.

Studying the Hypothalamic Insulin Signal to Peripheral Glucose Intolerance with a Continuous Drug Infusion System into the Mouse Brain.

Insulin regulates systematic metabolism in the hypothalamus and the peripheral insulin response. An inflammatory reaction in peripheral adipose tissues contributes to type 2 diabetes mellitus (T2DM) development and appetite regulation in the hypothalamus. Chemokine CCL5 and C-C chemokine receptor type 5 (CCR5) levels have been suggested to mediate arteriosclerosis and glucose intolerance in type 2 diabetes mellitus (T2DM). In addition, CCL5 plays a neuroendocrine role in the hypothalamus by regulating food intake and body temperature, thus, prompting us to investigate its function in hypothalamic insulin signaling and the regulation of peripheral glucose metabolism. The micro-osmotic pump brain infusion system is a quick and precise way to manipulate CCL5 function and study its effect in the brain. It also provides a convenient alternative approach to generating a transgenic knockout animal. In this system, CCL5 signaling was blocked by intracerebroventricular (ICV) infusion of its antagonist, MetCCL5, using a micro-osmotic pump. The peripheral glucose metabolism and insulin responsiveness was detected by the Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT). Insulin signaling activity was then analyzed by protein blot from tissue samples derived from the animals. After 7-14 days of MetCCL5 infusion, the glucose metabolism and insulin responsiveness was impaired in mice, as seen in the results of the OGTT and ITT. The IRS-1 serine302 phosphorylation was increased and the Akt activity was reduced in mice hypothalamic neurons following CCL5 inhibition. Altogether, our data suggest that blocking CCL5 in the mouse brain increases the phosphorylation of IRS-1 S302 and interrupts hypothalamic insulin signaling, leading to a decrease in insulin function in peripheral tissues as well as the impairment of glucose metabolism.

Periarticular Liposomal Bupivacaine Injection Versus Intra-Articular Bupivacaine Infusion Catheter for Analgesia After Total Knee Arthroplasty: A Double-Blinded, Randomized Controlled Trial.

BACKGROUND: Intra-articular bupivacaine hydrochloride (HCl) infusion catheters and periarticular injections of liposomal bupivacaine are often used as postoperative local anesthetics. The purpose of this study was to compare the efficacies of these local anesthetics following total knee arthroplasty. METHODS: This study was a superiority trial with a randomized, controlled, double-blinded design. Patients were randomly assigned to either delivery of bupivacaine HCl by the ON-Q* Pain Relief System pump (n = 96) or by an injection of Exparel (liposomal bupivacaine) (n = 104). The primary outcome of this study was cumulative narcotic consumption on postoperative days 0 through 3. Narcotic consumption data were collected retrospectively from in-hospital records while patients were in the hospital. Following discharge, narcotic consumption data were gathered from patient surveys, as were secondary outcomes measures. RESULTS: We did not identify greater narcotic use in the ON-Q* group compared with the Exparel group (p = 0.641). The mean difference between the groups was 0.5 morphine equivalent (95% confidence interval [CI] = -1.7 to +2.8), with the ON-Q* group consuming an average 10.4 morphine equivalents (95% CI = 8.7 to 12.0) compared with 10.9 (95% CI = 9.3 to 12.5) in the Exparel group. There were no significant differences between groups with regard to any of the secondary measures of pain with the exception of pain while walking and pain with physical therapy (p = 0.019 and p = 0.010, respectively), both of which showed an approximately 1-point difference in favor of the ON-Q* group on a visual analog scale (VAS). There were also no differences in the postoperative side effects, including nausea, constipation, or vomiting, or in the rates of study-related complications, patient satisfaction, or length of hospital stay. CONCLUSIONS: Exparel did not have superior efficacy compared with the ON-Q* Pain Relief System as reflected by narcotic consumption, our primary outcome. There were small significant differences, in favor of the ON-Q* group, in 2 secondary measures of pain during activity, but these approximately 1-point VAS differences are unlikely to be clinically relevant. The choice of a local anesthetic modality should be based on a combination of safety, convenience, and cost considerations. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of the Carefusion Alaris PC infusion pump for hyperbaric oxygen therapy conditions: Technical report.

We present a standardized test methodology and results for our evaluation of the Carefusion Alaris PC infusion pump, comprising the model 8015 PC Unit and the model 8100 Large Volume Pump (LVP) module. The evaluation consisted of basic suitability testing, internal component inspection, surface temperature measurement of selected internal components, and critical performance testing (infusion rate accuracy and occlusion alarm pressure) during conditions of typical hyperbaric oxygen (HBO2) treatment in our facility's class A multiplace chamber. We have found that the pumps pose no enhanced risk as an ignition source, and that the pumps operate within manufacturer's specifications for flow rate and occlusion alarms at all stages of HBO2 treatments, up to 4.0 ATA and pressurization and depressurization rates up to 180 kPa/minute. The pumps do not require purging with air or nitrogen and can be used unmodified, subject to the following conditions: pumps are undamaged, clean, fully charged, and absent from alcohol cleaning residue; pumps are powered from the internal NiMH battery only; maximum pressure exposure 4.0 ATA; maximum pressurization and depressurization rate of 180 kPa/minute; LVP modules locked in place with retaining screws.

Continuous Transversus Abdominis Plane Nerve Blocks: Does Varying Local Anesthetic Delivery Method-Automatic Repeated Bolus Versus Continuous Basal Infusion-Influence the Extent of Sensation to Cold?: A Randomized, Triple-Masked, Crossover Study in Volunteers.

BACKGROUND: It remains unknown whether continuous or scheduled intermittent bolus local anesthetic administration is preferable for transversus abdominis plane (TAP) catheters. We therefore tested the hypothesis that when using TAP catheters, providing local anesthetic in repeated bolus doses increases the cephalad-caudad cutaneous effects compared with a basal-only infusion. METHODS: Bilateral TAP catheters (posterior approach) were inserted in 24 healthy volunteers followed by ropivacaine 2 mg/mL administration for a total of 6 hours. The right side was randomly assigned to either a basal infusion (8 mL/h) or bolus doses (24 mL administered every 3 hours for a total of 2 bolus doses) in a double-masked manner. The left side received the alternate treatment. The primary end point was the extent of sensory deficit as measured by cool roller along the axillary line at hour 6 (6 hours after the local anesthetic administration was initiated). Secondary end points included the extent of sensory deficit as measured by cool roller and Von Frey filaments along the axillary line and along a transverse line at the level of the anterior superior iliac spine at hours 0 to 6. RESULTS: Although there were statistically significant differences between treatments within the earlier part of the administration period, by hour 6 the difference in extent of sensory deficit to cold failed to reach statistical significance along the axillary line (mean = 0.9 cm; SD = 6.8; 95% confidence interval -2.0 to 3.8; P = .515) and transverse line (mean = 2.5 cm; SD = 10.1; 95% confidence interval -1.8 to 6.8; P = .244). Although the difference between treatments was statistically significant at various early time points for the horizontal, vertical, and estimated area measurements of both cold and mechanical pressure sensory deficits, no comparison remained statistically significant by hour 6. CONCLUSIONS: No evidence was found in this study involving healthy volunteers to support the hypothesis that changing the local anesthetic administration technique (continuous basal versus hourly bolus) when using ropivacaine 0.2% and TAP catheters at 8 mL/h and 24 mL every 3 hours significantly influences the cutaneous effects after 6 hours of administration. Additional research is required to determine whether changing variables (eg, local anesthetic concentration, basal infusion rate, bolus dose volume, and/or interval) would provide different results.

An assessment of the performance of the Baxter elastomeric (LV10) Infusor™ pump under hyperbaric conditions.

INTRODUCTION: There are limited data on the use of elastomeric infusion pumps during hyperbaric oxygen treatment. AIM: This study evaluated the flow rate of the Baxter elastomeric LV10 Infusor™ pump under normobaric (101.3 kPa) and three hyperbaric conditions of 203 kPa, 243 kPa and 284 kPa. METHODS: Elastomeric pumps were secured to participants in the same manner as for a typical patient, except that a container collected the delivered antibiotic solution. Pumps and tubing were weighed before and after the test period to determine volume delivered and to calculate flow rates at sea level and the three commonly used hyperbaric treatment pressures at two different time periods, 0-2 hours (h) and 19-21 h into the infusion. RESULTS: The mean flow rates in ml·h⁻¹ (SD) were: 9.5 (0.4), 10.3 (0.6), 10.4 (0.6), 10.4 (0.5) at 0-2 h and 10.5 (1.0), 12.2 (0.6), 9.4 (0.5), 10.3 (0.9) at 19-21 h for the normobaric, 203 kPa, 243 kPa and 284 kPa conditions respectively. There was no significant association between flow rate and time period (P = 0.166) but the 203 kPa flow rates were significantly faster than the other flow rates (P = 0.008). In retrospect, the 203 kPa experiments had all been conducted with the same antibiotic solution (ceftazidime 6 g). Repeating that experimental arm using flucloxacillin 8 g produced flow rates of 10.4 (0.8) ml·h⁻¹, with no significant associations between flow rate and time period (P = 0.652) or pressure (P = 0.705). CONCLUSION: In this study, the flow rate of the Baxter LV10 Infusor™ device was not significantly affected by increases in ambient pressure across the pressure range of 101.3 kPa to 284 kPa, and flow rates were generally within a clinically acceptable range of 9-12 ml·h⁻¹. However, there was evidence that the specific antibiotic solution might affect flow rates and this requires further study.