Pen Needle Research Articles

Pen Preference

Controversy and confusion exists around appropriate needle length for injecting insulin. The goal of this study is to evaluate patient satisfaction and efficacy of treatment as determined by A1c levels, when using a 5mm pen needle compared to a 8mm pen needle.

Administration Technique and Storage of Disposable Insulin Pens Reported by Patients With Diabetes

The purpose of the study was to evaluate insulin injection technique and storage of insulin pens as reported by patients with diabetes and to compare correct pen use to initial education on injection technique, hemoglobin A1C, duration of insulin therapy, and duration of insulin pen. Cross-sectional questionnaire orally administered to patients at a university-affiliated primary care practice. Subjects were patients with diabetes who were 18 years or older and prescribed a disposable insulin pen for at least 4 weeks. A correct usage score was calculated for each patient based on manufacturer recommendations for disposable insulin pen use. Associations were made between the correct usage score and certainty in technique, initial education, years of insulin therapy, duration of pen use, and hemoglobin A1C. Sixty-seven patients completed the questionnaire, reporting total use of 94 insulin pens. The 3 components most often neglected by patients were priming pen needle, holding for specific count time before withdrawal of pen needle from skin, and storing an in-use pen. For three-fourths of the insulin pens being used, users did not follow the manufacturer's instructions for proper administration and storage of insulin pens. Correct usage scores were significantly higher if initial education on insulin pens was performed by a pharmacist or nurse. The majority of patients may be ignoring or unaware of key components for consistent insulin dosing using disposable insulin pens; therefore, initial education and reeducation on correct use of disposable insulin pens by health care professionals are needed.

Skin and subcutaneous thickness at injecting sites in children with diabetes: ultrasound findings and recommendations for giving injection

Children who inject insulin need clear guidelines as to the length of needle best for them. We studied the distance from surface to muscle in children in order to make needle choices which are evidence-based. One hundred one children with type 1 diabetes were divided into three groups according to age: 2-6, 7-13, and 14-17 yr. The thickness of skin and subcutaneous (SC) tissue was measured by ultrasound in all injection sites. Skin thickness varied from 1.58 mm in the arm of the youngest children to 2.29 mm in the buttocks of the adolescents. Values decreased progressively based on age (2-6 < 7-13 < 14-17) and on body site (arm < thigh < abdomen < buttocks). Skin + SC thickness varied in a similar fashion. The skin surface to muscle distances were <4 mm in nearly 10% of children, especially in the 2-6 yr group. In this group, the rate of intramuscular (IM) injections using the 4-mm pen needle when a pinch-up is not used would be 20.2%. This rate of IM injections doubles when using the 5-mm needle, and when injections are given under similar conditions it triples using the 6-mm needle. It seems medically appropriate for all children to use short needles where possible to minimize inadvertent IM injections which may increase glycemic variability. Currently, the safest needle for all children appears to be the 4-mm pen needle. However, when used in children aged 2-6 yr, it should be used with a pinched skin fold.

The AutoShield Pen Needle is Useful for Preventing Accidental Puncture While Administering Insulin to others by Injection

Diabetes patients usually perform insulin injection on themselves (self-injection); however, caregivers also administer insulin to patients (other-injection).1 The use of insulin injection pens with needles sometimes causes accidental puncture. Furthermore, if the patient has an infectious disease such as human immunodeficiency virus or Hepatitis C virus, accidental puncture during other-injection can result in transmission of the infectious disease to the caregiver.2,3 The AutoShield® Pen Needle (Becton, Dickinson and Company, Franklin Lakes, NJ), which recaps automatically and prevents accidental puncture,4 has been available in Japan since 2011. However, the ease of use of the AutoShield has not been evaluated. We evaluated the ease of use of the AutoShield by comparing it with the PenNeedle® 32G (Novo Nordisk A/S, Bagsvaerd, Denmark) in other-injection settings: injection to the arm and injection to the abdomen. Our study group included 30 respondents [mean (standard deviation), 38.4 (9.0) years, (range, 24–59 years)] comprising 15 women (50%) and 15 men (50%). Respondents answered a questionnaire (Table 1) immediately after performing injections. Results were scored from 1 to 5. We performed a comprehensive evaluation and investigated individual questionnaire items to determine the differences between the AutoShield and the PenNeedle. Univariate and multivariate analysis were performed using Statview 5.0 software (SAS Institute Inc., Cary, NC) and significance was defined as p < .05. Table 1 Questionnaire Used in the Present Study The AutoShield was significantly superior to the PenNeedle in both injection to the arm [AutoShield 3.63 (1.07), PenNeedle 3.03 (0.67), p = .012] and injection to the abdomen [AutoShield 3.40 (0.97), PenNeedle 2.87 (0.57), p = .012] in the comprehensive evaluation. Univariate analysis revealed that AutoShield length (needle + device) was significantly inferior (too long) compared with the PenNeedle in both injection to the arm [AutoShield 3.37 (0.89), PenNeedle 2.93 (0.64), p < .001] and injection to the abdomen [AutoShield 3.80 (0.61), PenNeedle 3.00 (0.37), p < .001]. However, the AutoShield was significantly superior to the PenNeedle in preventing accidental puncture in both injection to the arm [AutoShield 4.67 (0.55), PenNeedle 3.07 (0.83), p < .001] and injection to the abdomen [AutoShield 4.67 (0.55), PenNeedle 2.93 (0.83), p < .001]. Multivariate analysis revealed that length (needle + device; p = .013) and accidental puncture (p < .001) were significantly different between AutoShield and PenNeedle for the arm. Also, for the abdomen, length (needle + device; p = .023) and accidental puncture (p = .013) were evaluated as significant. The length (needle + device) of the AutoShield was too long, but the AutoShield was superior to the PenNeedle regarding prevention of accidental puncture and in the comprehensive evaluation. We propose that needles for other-injection should be equipped with an automatic recapping ability. Although needles with an automatic recapping ability are more expensive than conventional needles, they may prevent accidental puncture and the spread of infectious diseases.

Impact of a Modified Needle Tip Geometry on Penetration Force as Well as Acceptability, Preference, and Perceived Pain in Subjects with Diabetes

Multiple factors impact subcutaneous insulin injection pain. Injection devices [e.g., syringe or pen needle (PN)] affect pain due to needle length, diameter, needle polishing and lubrication, and needle tip geometry. We evaluated a modified 5-bevel PN tip in 32 G × 4 mm 31 G × 5 mm and 8 mm PNs vs the equivalent marketed 3-bevel PNs in laboratory penetration force testing, as well as in insulin-taking subjects for overall acceptability, comparative pain, and preference. The clinical tests were done in three ways: paired insertions with the subjects blinded to PN tip geometry, after brief at-home use of 5-bevel PNs, and again with subjects informed about each needle's tip geometry in paired insertions. Average penetration force in a skin substitute was 23% lower with the 5-bevel PNs vs similar 3-bevel PNs (p ≤ 0.01). In blinded testing and after at-home use, patients rated the 5-bevel needle as acceptable. After shortterm home use, patients rated the 5-bevel PN less painful and preferable to their usual PN (both p < 0.01). In paired, informed testing, the 5-bevel PN was less painful and preferred to subjects' currently used needles (p ≤ 0.01) and to other marketed PNs (p < 0.01). Needle tip geometry affects penetration force. When blinded, patients did not distinguish differences in PN tip geometry with fine-gauge PN insertions. A 5-bevel needle tip is perceived as less painful and is preferred by subjects following home use for usual injections. Similar results occurred when patients were informed that they were using a needle with a modified tip.

New ways of insulin delivery

New ways of insulin delivery

Needlestick injuries in European nurses in diabetes

With the June 2010 publication of EU Council Directive 2010/32/EU scrutiny is now being focused on the safety and protection of diabetes nurses. We used a questionnaire to study the frequency and risks of Needlestick Injuries (NSI) associated with diabetic injections in European hospitals. 634 nurses participated from 13 western European countries and Russia. When patients with diabetes who self-inject at home are hospitalized injections are given always by the staff in 31% of cases, by the patients themselves where possible in 33%, initially by staff, then the patient takes over in 12% and both staff and patient throughout the stay in 21%. 86% of nurses said their hospitals had a written policy on the prevention of NSI but, where it was available, only 56% were familiar with it. 67% of the nurses had not attended any training on the prevention of NSI and only 13% had attended one in the last year. 7.1% of nurses report recapping needles and 5.9% report storing unprotected needles temporarily on a tray, trolley or cart. 32% of nurses report suffering a NSI while giving a diabetic injection at some point in the past. 29.5% of NSI occurred while recapping a used needle. 57% of nurses unscrew pen needles using their own fingers. In 80% cases the source patient's identity was known and the sharp item was "contaminated" (known previous percutaneous exposure to patient) in almost half the cases (43%). NSIs were reported to the proper authorities in only 2/3 of cases. Our study shows that frequent NSI occur in European nurses treating people with diabetes in hospital settings. These injuries are a source of possible infection despite the small size of diabetes needles. The introduction of safety-engineered medical devices has been shown to reduce the risk of injury. A new European Directive that has now come into force specifically stipulates that wherever there is risk of sharps injury, the user and all healthcare workers must be protected by adequate safety precautions, including the use of "medical devices incorporating safety-engineered protection mechanisms".

Subcutaneous adipose tissue thickness in adults - correlation with BMI and recommendations for pen needle lengths for subcutaneous self-injection

One of the aims of a subcutaneous (SC) injection is to avoid intradermal or intramuscular injections. Pen systems are an alternative solution to single-use syringes and have become standard for example diabetes therapy. Shorter and smaller needles minimize pain and the risk of intramuscular injections. The thickness of subcutaneous adipose tissue (SCAT) varies with position and with body mass index (BMI). The aim of this study was the creation of a map of SCAT thickness at typical spots for SC self-injection. MRI scans of 116 prospectively enroled volunteers (56 men and 60 women) were analysed. SCAT thickness was determined at 17 spots over the abdominal wall, left thigh, buttocks and upper arm, typical sites for subcutaneous self-injection. SCAT thicknesses were correlated with BMI and waist-to-hip ratio (WHR), and a linear curve fit was performed. The best fitting linear functions for the prediction of the SCAT thickness dependent on BMI and WHR were derived. Correlations between SCAT and BMI were higher (0·67-0·21) than with WHR (-0·67 to 0·09). In women, correlation coefficients between SCAT data at the abdomen and BMI/WHR were higher than in men. On the other hand, data showed better correlations at the extremities in men. The data, with correlation between BMI and fat thickness at different injection sites in relation to gender, provide guidance in selecting an adequate pen needle length for deep and safe subcutaneous self-injection. WHR was a much weaker predictor when compared to BMI.

Analysis of the NovoTwist pen needle in comparison with conventional screw-thread needles.

Administration of insulin via a pen device may be advantageous over a vial and syringe system. Hofman and colleagues introduce a new insulin pen needle, the NovoTwist, to simplify injections to a small group of children and adolescents. Their overall preferences and evaluation of the handling of the needle are reported in the study. This new needle has the potential to ease administration of insulin via a pen device that may increase both the use of a pen device and adherence to insulin therapy.

Needle with a Novel Attachment versus Conventional Screw-Thread Needles: A Preference and Ease-of-Use Test among Children and Adolescents with Diabetes

This usability test investigated the overall preference and usability of the novel NovoTwist® insulin pen needle versus conventional screw-thread needles, when used with Next Generation FlexPen®, in children and adolescents with diabetes. This was an open-label, randomized, crossover usability test in children and adolescents with type 1 diabetes who administered insulin with an insulin pen. Test needles were NovoTwist and the participant's current screw-thread needle (or NovoFine® needle). Following instruction, participants attached the needle to Next Generation FlexPen, made an injection into a foam cushion, and detached the needle. This procedure was conducted three times with both needles in a random order. Responses to 13 questions on user experience with each needle (including overall preference, ease of attachment/detachment of needle/cap, handling, learning, confidence in attachment, and convenience of use) were subsequently recorded on a six-point rating scale (1 = very difficult; 6 = very easy). Fifteen children aged ≥ 6 to ≤ 12 years and 15 adolescents aged ≥ 13 to ≤ 17 years participated in the test. A significantly higher proportion of children and adolescents (77%) indicated that they would prefer to use NovoTwist compared with screw-thread needles (p = .005). NovoTwist was preferred by most children and adolescents for overall ease of use (77%; p = .005), for ease of attachment (87%; p < .001) and detachment (83%; p < .001), and as the most appropriate needle to handle for daily injections (73%; p = .016). The mean rating for confidence in correct needle attachment was not significantly different between the two needle types. Seven out of eight parents of children who required assistance for their daily insulin injections stated that they would be "very likely" to allow their child to attach NovoTwist. These factors may promote confidence in this needle, and thus in self-injecting, among younger patients and their parents.

Randomized Trial on the Influence of the Length of Two Insulin Pen Needles on Glycemic Control and Patient Preference in Obese Patients with Diabetes

This study determined the influence of needle length for insulin administration on metabolic control and patient preference in obese patients with diabetes mellitus. In this multicenter, open-label crossover study, insulin pen needles of two different lengths (5 mm and 8 mm) were compared. A total of 130 insulin-treated type 1 and type 2 diabetes patients with a body mass index ≥30 kg/m(2) were randomized, and 126 patients completed the study. Patients started using the 5-mm needle for 3 months, after which they switched to injecting insulin with the 8-mm needle for another 3 months, or vice versa. Hemoglobin A1c (A1C), fructosamine, and 1,5-anhydroglucitol were measured, and self-reported side effects and patient preference were recorded. No within-group changes were observed with respect to A1C, serum fructosamine, 1,5-anhydroglucitol, hypoglycemic events, bruising, and pain. When data of all 126 subjects were pooled, there was a small, but significant, difference between needle lengths (5-mm, A1C 7.47 ± 0.9%; 8-mm, 7.59 ± 1.0%; P = 0.02). Patients reported less bleeding with the 5-mm needle (P = 0.04) and less insulin leakage from the skin with the 8-mm needle (P = 0.01). There were no significant differences in patient preference, with 46% of the patients preferring the 5-mm needle, 41% the 8-mm needle, and 13% not preferring a particular needle length. A 5-mm needle is similar to an 8-mm needle in obese patients with diabetes with respect to metabolic control, injection-related complaints, or patient preference and can be used safely.

Compatibility testing of two types of pen needles with a range of injection pens for diabetes medication

Compatibility of two types of needles with a variety of durable and prefilled injection pens for diabetes medication was tested by attaching the needles according to ISO 11608-2 and verifying penetration into the cartridge using air shots and two-dimensional X-rays. NovoFine and NovoFine Autocover attached correctly to 20 and 19 out of 21 pen types, respectively. Neither needle type attached to Diapen 3.1/3.2, while NovoFine Autocover attached to most, but not all of OptiSet pens.

The Risks of Repeated Use of Insulin Pen Needles in Patients with Diabetes Mellitus

The Risks of Repeated Use of Insulin Pen Needles in Patients with Diabetes Mellitus

Insulin Leakage Value in Relation to Pen Needle Length and Administered Dose After Subcutaneous Injection

During a subcutaneous injection with commonly used pen needles, the safety of drug administration plays an essential role. Today short needles with a length of 5.0 mm are increasingly being used. However, so far it is unresolved whether short needles of <5.0 mm affect the safety of insulin injections because of an increased backflow to the skin surface. We examined the influence of needle length and administered insulin dosage on the insulin backflow and the distribution of human insulin in the tissue by a quantitative determination of the amount of backflow of insulin to the skin surface. For the first time a new 4.5-mm pen needle was examined for its administration safety. Human insulin was radioactively marked. By means of an insulin pen different insulin dosages with pen needles of different lengths into fresh pork rind (ex vivo model) were administered. The amount of the marked insulin leaking from the tissues at the injection site was covered and absorbed immediately into a cotton swab. The amount of leakage was calculated by means of the radioactivity taken up by the swab. The amount of leakage for each measurement was less than 1% of the total dosage administered. The amount of leakage increased with increased dosage administered in absolute terms, but expressed as a percentage of the increased dosage administered the leakage decreased. The needle length (between 12 mm and 4.5 mm) did not have a meaningful influence on the amount of leakage; however, significant differences with different needle lengths could be observed.

Pen Needles

Pen Needles

The Insulin Pen May Be Mightier Than You Think

MR. WENDT is vice president of pharmacy services and clinical operations for Fundamental Clinical Consulting, LLC, which is the parent company of more than 100 skilled nursing facilities, hospices, and home care divisions in 10 states. Insulin pens are expensive, whereas vials are cheap, right? You might be surprised to learn that the typical nursing facility could save thousands of dollars each year by going with the pens for diabetic residents. The key is that 35%-40% of insulin in vials is wasted because pharmacy regulations typically say that a vial must be discarded 28 days after its first puncture. Do the math. A 10-cc vial contains 1,000 units. A typical resident receives 20 units per day, taking just 560 units in those 28 days of vial life. The remaining 440 units have to be tossed. If the 1,000-unit vial costs about $120, that's a staggering waste per patient per month of roughly $50. The average 100-bed facility has more than 30 insulin-dependent residents, so wasted insulin costs it $1,500 per month, or $18,000 annually. And those figures don't include the cost of time spent by the director of nursing and consultant pharmacist in processing the vial's destruction. The insulin pen, under the right circumstances, can provide substantial savings and improve dosing accuracy. Take the given example of 20 units per day per diabetic resident and introduce into the equation the 300-unit insulin pen. The facility nurse would be required to order two pens per patient in the course of the month, none of which would ever have to be discarded because they are used before reaching the 28-day window. The cost of each 300-unit pen is typically $45-$48. Add an extra $10 per month for the more expensive pen needles, and savings as a result of the switch to the pen delivery system would be at least $20-$30 per month per patient. The savings can reach $50 per month depending on the daily insulin dose. The insulin pen's mechanism allows the nurse to determine the appropriate dose by dialing the pen top. For a lot of people, this is far more accurate than trying to adjust a meniscus by sight inside a syringe. I have found that the most nurses greatly prefer administering insulin by the pen after they have tried it. And if a new vial is dropped and broken, it costs $120 to replace the 1,000 units of insulin on the floor. A pen is not only less fragile, but also costs much less to replace. But the pen is not always the most financially beneficial system. The rule of thumb for minimizing waste is that daily doses in excess of 30 units per day are best provided by vials. Once you're required to order more than two pens in a 28-day period per patient, the cost savings for the pen disappears. Thus, economizing does take some thinking on the part of nursing and support from a pharmacy partner. The dispensing pharmacist should tell a facility which delivery system would be the least costly for its particular mix of diabetes patients. The good news for residents using Medicare Part D is that most plans cover the insulin pens and needles. However, not every state Medicaid program has insulin pens on its formulary. The pharmacy provider for your facility can tell you if Medicaid coverage is a problem. The pen is also a good choice for residents who may be discharged home or to assisted living. Especially for those with vision problems, the pen offers a much more accurate dosing mechanism that the patient or the caregiver can manage with confidence. Some insulin and device suppliers have begun to introduce a limited number of 3-cc (300-unit) vials. These should save costs when used appropriately. Moving to an insulin pen has proven popular among residents. Many, when being discharged home, ask for their physicians to order the pen for them.

Comparative glycemic control, safety and patient ratings for a new 4 mm × 32G insulin pen needle in adults with diabetes

Objective:Pen needles (PN) for subcutaneous insulin therapy have become smaller; 5 mm PNs are now the shortest in use. We evaluated the safety, efficacy and patient ratings of a new 4 mm × 32 gauge (G) PN.Research design and methods:Subjects with type 1 and type 2 diabetes and HbA1c 5.5% to 9.5% participated in a randomized non-inferiority cross-over trial, at four U.S. centers. Subjects used 4 mm × 32G PNs and either 5 mm × 31G PNs (4/5 mm) or 8 mm × 31G PNs (4/8 mm) in two, 3-week treatment periods; order of needle use was controlled. Subjects were either ‘low dose’ or ‘regular dose’ users (highest single insulin dose ≤ 20 units and 21–40 units, respectively). Percent absolute change in serum fructosamine (% |Δ Fru|) was the primary endpoint; unexplained, severe hypo- or hyperglycemia was a secondary measure. Leakage at injection sites and pain measured by visual analog scale were tertiary measures. Equivalent glycemic control was defined á priori as % |Δ Fru| (including 95% CI) within 20%; 40 subjects per subgroup provides 90% power at α = 0.05.Clinical trial registration:The study was registered on clinicaltrials.gov (identifier: NCT00928057).Results:Of 173 subjects randomized, 168 completed the study, and 163 were included in the fructosamine analyses – 83 and 80 in the 4/5 mm and 4/8 mm groups, respectively. Subjects were 56% male, mean 52.6 yrs, 63% type 2. Baseline HbA1c = 7.5 ± 1.0% and fructosamine 301 ± 55.1 μmol/L. Mean % |Δ Fru| was 4.9% (95% CI 3.8, 6.0) and 5.5% (4.5, 6.4), respectively, for the 4/5 mm and 4/8 mm groups, meeting glycemic equivalence criteria; results were similar in both dose groups. The median |Δ Fru| was 11.0 μmol/L (8.0, 13.0) and 13.5 μmol/L (9.8, 18.0) for the 4/5 mm and 4/8 mm groups, respectively. Unexplained, severe hypo- and hyperglycemic episodes were infrequent and not different between PNs. The 4 mm PN was rated significantly less painful and preferred by approximately 2/3 of subjects (p < 0.01). All three PNs had similar reported injection site leakage.Limitations:The study was of relatively short duration, in adults in the U.S. Further trials in other patients (e.g., GLP-1 users, pediatrics, obese) should be performed.Conclusions:The 4 mm × 32G PN provided equivalent glycemic control compared to 31G, 5 mm and 8 mm PNs with reduced pain, no difference in insulin leakage and was preferred by patients.

Lipoatrophy associated with the use of insulin analogues: a new case associated with the use of insulin glargine and review of the literature

Importance of the field: Any insulin formulation can in principle cause lipoatrophy; even cases associated with recombinant human insulin have been reported. An increasing number of case reports have been published indicating that lipoatrophy also develops after treatment with various insulin analogues.Areas covered in this review: In this review, we summarise the literature on lipoatrophy associated with the use of insulin analogues published to date. A new case of lipoatrophy associated with the use of glargine is presented.What the reader will gain: Readers will gain insight into: i) pathogenesis of lipoatrophy associated with the use of insulin analogues and ii) clinical features of lipoatrophy.Take home message: Twelve cases with lipoatrophy under treatment with insulin analogues have been reported so far. The exclusive occurrence in lean type 1 diabetic patients, its overlap with further autoimmune diseases and the overrepresentation of female individuals point to an immune pathogenesis. The respective exposition to the analogues lispro, aspart, glargine and detemir prior to lipoatrophy development varied considerably between 4 weeks and 2 years. No spontaneous substantial recovery of lipoatrophic areas has been reported. Frequent use of the same pen needle and lack of rotating of insulin injection sites seem to favour the development of lipoatrophy.

Danger of multiple use of insulin pen needles for diabetic patients

Aim. To evaluate the risk of multiple use of BD Micro-Fine Plus insulin pen needles in terms of their contamination with microflora, pain and localreaction at the injection site. Materials and methods. The study included 45 patients aged above 18 yr with type 1 and 2 diabetes mellitus (DM1 and DM2) treated with shortorultrashort-acting insulins TID. Account was taken of the time each needle was used (once, for 4 and 7 days). Microbiological analysis was madeat the respective time points. Pain sensation after injection was evaluated by patients themselves using a visual-analog scale and severity of local reactionsby the physician. Results. Microbial growth was documented in 20 and 33,3% of the patients who used needles ones or many times respectively. Patients of the lattergroup more frequently complained of pain after injection (on day 4, p=0,08) compared with those of the former one (on day 7, p=0,03). Hyperemicfoci at injection sites developed only in case of using the same needle for 4 and 7 days (13,3 and 26,6% respectively). Conclusion. Multiple use of insulin pen needles by patients with DM should be avoided since it leads to hyperemia at injection sites, pain sensation,and risk of microbial contamination.

Insulin treatment in children and adolescents with diabetes

Department of Pediatrics, Uddevalla Hospital, Uddevalla,SwedenCorresponding author:Hans-Jacob Bangstad, MDDepartment of PaediatricsOslo University HospitalUlleval˚Kirkeveien 166Oslo N-0407Norway.Tel: 0047-22118765;fax: 0047-22118663;e-mail: haba@uus.noConflicts of interest: RH has received lecture honoraria fromNovo Nordisk, Lilly, Sanofi-Aventis, Medtronic and Roche. PJ-Chas received lecture fees from Eli Lilly, Novo-Nordisk, Sanofi-Aventis, Abbott, Bayer, Medtronic and Roche.The remainingauthors have declared no potential conflicts.Editors of the ISPAD Clinical Practice Consensus Guide-lines 2009 Compendium: Ragnar Hanas, Kim Donaghue,Georgeanna Klingensmith, and Peter Swift.This article is a chapter in the