Fine bore silicone catheters for peripheral intravenous nutrition in adults

Peripheral parenteral nutrition

BACKGROUND

Peripheral parenteral nutrition (PPN) currently accounts for almost 20 per cent of all parenteral nutrition administered in the UK. In the absence of consensus guidelines there is wide variation in practice. Heterogeneity of clinical trials has made direct comparisons difficult and meta-analysis impossible.

METHODS

Medline, Embase and Cochrane databases were searched for all clinical trials relating to the use of PPN in adults. Relevant papers from the reference lists of these articles and from the authors' personal collections were also reviewed.

RESULTS AND CONCLUSIONS

Effective PPN is possible in about 50 per cent of inpatients requiring parenteral nutrition. Evidence relating to optimal feed composition, choice of cannula, infusion technique and pharmacological manipulation is discussed, along with practical recommendations for the administration of PPN.

The local vascular tolerance to an intravenous infusion of a concentrated glutamine solution in ICU patients

BACKGROUND AND AIMS

The beneficial effects of glutamine is well-documented in ICU patients. However, the documentation and control of enteral administration of glutamine is still insufficient. As an adjunct to enteral nutrition, a concentrated dipeptide solution may be given in a central venous line, but administration via a peripheral vein would be preferable. Therefore, we systematically evaluated local vascular tolerance following a concentrated dipeptide infusion in ICU-patients.

METHODS

ICU-patients (n=20) were randomized to receive a 20% alanyl-glutamine infusion of 0.5 g/kg or placebo during 4 h in a peripheral vein on 3 consecutive days. Local tolerance was evaluated clinically, by Maddox score, and ultrasonically before the infusion and on days 1, 4 and 8 after the infusion.

RESULTS

In the study, 56 out of 60 (93%) planned infusions were administered and 157 out of 168 (93%) clinical evaluations were successfully performed. The ultrasonic evaluation revealed that the utilized veins had a diameter of 2.15+/-0.8 mm (range, 1.0--4.4 mm). There were no signs of thrombophlebitis in any single vein.

CONCLUSION

Administration of a glutamine-containing dipeptide concentrate (20%) by peripheral veins is safe in terms of local tolerance, if a strict protocol is adapted for this purpose is used.

Ultrasonic investigation of the effect of topical glyceryl trinitrate on peripheral arm vein diameter: implications for intravenous nutrition

BACKGROUND

It has been suggested that topical glyceryl trinitrate (GTN) ointment may cause venodilatation and hence deter thrombophlebitis. However, objective evidence of an increase in vein diameter has not been demonstrated.

METHODS

B mode ultrasonography was used to measure arm vein diameter. In a prospective study, measurements were taken before and after 24 hours of exposure to topical GTN.

RESULTS

Reproducibility of vein diameter measurement was demonstrated. Basilic veins were larger than cephalic veins, but exposure to GTN ointment for 24 hours was not associated with measurable venodilatation.

CONCLUSIONS

Ultrasonography enabled noninvasive measurement of intraluminal vein diameter. It is unlikely that GTN prevents thrombophlebitis in superficial arm veins by causing venodilatation.

Incidence of vein thrombosis in peripheral intravenous nutrition: effect of fat emulsions

The relative risk of thrombophlebitis induced by either Long-chain Triglycerides (LCTs) or Medium-chain Triglycerides (MCTs) during peripheral i.v. nutrition (PIN) was evaluated. A total of 76 patients were randomly assigned into group A (n=40) and group B (n=36). The nutritional requirements in both groups were covered by a standardized regime of osmolality 1130 mOsm and pH 5.2, which provided 14 kg/day(-1) nitrogen, 600 kcal/day(-1) of carbohydrates and 1000 kcal/day(-1) of lipids. Group A received the lipids as pure LCTs while group B received a mixture of LCTs/MCTs at a ratio 1:1. The infused nutritional volume was 2000 ml and was delivered via a suitable vein in a proximal forearm, using a fine bore polyurethane 22G catheter. The two standardized regimes were evaluated over a 10 day period regarding the incidence of thrombophlebitis. The cumulative risk of thrombophlebitis was documented to be significantly lower in group A compared to group B (17.5% versus 44.4%, P < 0.05). LCTs appear to prolong peripheral vein feeding by lessening the reaction of venous endothelium to the irritating nutritional infusate.

Fine-bore cannulas for peripheral intravenous nutrition: polyurethane or silicone?

The peripheral intravenous route is being used more frequently for the administration of short- to medium-term parenteral nutritional support. Dedicated fine bore cannulas have significantly reduced the incidence of thrombophlebitis. Currently available cannulas are made of polyurethane or silicone. We present our experience with a 23G silicone cannula and a 22G polyurethane alternative. Fifty-four silicone cannulas were used with a median survival of only 3 days, compared with 7 days for 90 polyurethane cannulas (P < 0.0001). Only 22% of silicone cannulas were removed electively compared with 56% of polyurethane cannulas (P < 0.00005). The most common cause for silicone cannula removal was occlusion (48%), which occurred in only 8% of polyurethane cannulas (P < 0.00001). Polyurethane cannulas develop fewer complications and are more effective in the delivery of peripheral intravenous nutritional support.

Influence of fine-bore catheter length on infusion thrombophlebitis in peripheral intravenous nutrition: a randomised controlled trial

Previous studies indicated that the risk of thrombophlebitis associated with continuous infusion of intravenous nutrition (IVN) via peripheral veins was reduced when fine-bore catheters, inserted to 15 cm, were used in place of standard intravenous cannulas. An explanation has not been identified, but may be owing to the greater length of the catheters. A randomised controlled study was performed in which a standard nutritional solution was infused via 22G polyurethane catheters inserted to a length of either 5 cm or 15 cm. Catheters were reviewed twice each day and removed when complications occurred, or when IVN was no longer required. There was no significant difference in median time to thrombophlebitis or extravasation, or in daily risk of thrombophlebitis, between insertion lengths. Survival proportions were similar for each length at all times. Catheters inserted into cephalic veins were more prone to thrombophlebitis or extravasation (nine episodes, 14 catheters) than catheters inserted into basilic veins (five episodes, 24 catheters, P = 0.009). The survival proportion was at all times greater when catheter tips lay in basilic veins. Thus, the risk of thrombophlebitis or extravasation was not influenced by the length of catheter within the vein. However, the vein in which the catheter tip lay appeared to influence the development of morbidity.

Administration of peripheral parenteral nutrition: a prospective study comparing rotation of venous access sites with ultrafine cannulas

Peripheral veins have been used successfully for patients requiring short- to medium-term total parenteral nutrition. This study prospectively compares two methods of peripheral parenteral nutrition (PPN). Forty-six patients requiring parenteral nutrition (PN) were identified prospectively. Fifty courses of PPN were prescribed using a standardized PPN formula of 9.3 g nitrogen, 1400 kCal, 2500 ml (KABI II, Pharmacia). Patients were randomized to receive PPN via 23G, 15 cm flexane catheters (Nutriline) inserted into an antecubital vein which remained in-situ with a continuous infusion over 24 h, or to receive 12-h cyclical infusions through peripherally sited 18G catheters (Venflon) which were removed postinfusion and reinserted into the contralateral forearm on alternate days. Data collected included duration, complications and cost of materials for each prescribed course. A scoring system to determine patient anxiety and depression and a questionnaire regarding patients' perspectives were evaluated. Fifty courses were prescribed, 26 by rotation of veins (RV) and 24 by Nutriline (N). Mean duration of feeding was 7.9 and 8.6 days, respectively; cost of materials were comparable 6.48/day (RV) vs 5.17/day (N); 2 RV patients failed to complete their course (no access [P< 0.05], whilst 9 N patients failed to complete their course (4 severe phlebitis, 2 no venous access, 2 septicaemia, 1 dislodged). Five patients required CPN (RV, N 3) while 4 remaining patients were fed by an alternative PPN method. The overall incidence of anxiety was 20% and of depression 16%, with no significant difference between groups. The majority of patients (87%) found mobility restricted. Twelve-hourly infusions via alternate forearm veins were significantly more successful than continuous infusions via Nutriline, both in terms of completion of the prescribed course and less venous morbidity. This study confirms that rotation of forearm veins allows affordable and successful PN administration to the majority of patients, with low PN-related morbidity.

High osmolality feedings do not increase the incidence of thrombophlebitis during peripheral i.v. nutrition

BACKGROUND

Peripheral i.v. nutrition has been advocated for patients who require short-term i.v. nutrition support to avoid the complications and expense of central venous catheterization. Feeding formulas for peripheral administration have usually been modified by increasing the proportion of lipid, because increasing osmolality is reported to cause thrombophlebitis. The aim of this study was to determine whether standard feeding formulas can be given via the peripheral route and also to establish whether increasing osmolality does increase the incidence of thrombophlebitis under these conditions.

METHODS

Thirty-six patients requiring parenteral nutrition were randomized to receive either a "high" (1700 mOsmol/L) or "standard" (1200 mOsmol/L) osmolality feeding containing 2000 kcal and 12 g nitrogen via a peripheral line.

RESULTS

Twenty patients (mean age 55.6 years, range 16 to 78) received standard osmolality feedings using 20 peripheral feeding lines for a mean duration of 6.8 days (range 2 to 16) with 10 line failures (8 thrombophlebitis, 2 occlusion). Nineteen patients (mean age 56.1 years, range 27 to 83) received high osmolality feedings via 20 lines for a mean of 6.3 days (range 0 to 18) with five line failures (4 thrombophlebitis, 1 occlusion), one failed insertion, one line removed at the patient's request, and four lines that fell out. Forty lines were inserted overall of which 19 (47.5%) were removed electively, 12 (30%) developed thrombophlebitis, 3 (7.5%) occluded, 4 (10%) fell out, 1 (2.5%) was a failed insertion, and 1 (2.5%) was removed for nonmedical reasons.

CONCLUSIONS

Increasing osmolality of total parenteral nutrition did not increase episodes of thrombophlebitis in this trial and did not affect the success rate of the lines. We conclude that standard total parenteral nutrition formulas of higher osmolality than previously thought can be safely given via the peripheral route for short-term feeding and do not increase the risk of thrombophlebitis.

Peripheral infusion as the route of choice for intravenous nutrition: a prospective two year study

A central venous catheter (CVC) is widely regarded as the standard route for delivery of intravenous nutrition (IVN). Peripheral venous infusion avoids the morbidity of a CVC, but may require regular resiting of standard intravenous cannulae, or compromise of the nutritional quality of the feed, to avoid thrombophlebitis. Fine-bore catheters, designed for use in neonates, have been associated with a much lower incidence of phlebitis when used for peripheral IVN in adults, but reports have been limited to selected groups of patients. A prospective study of 302 courses of IVN is presented in which a peripheral vein was the route of first choice. The composition of the feed was determined by the patient's metabolic requirement, and was not compromised to facilitate peripheral venous infusion. In 51% of all courses of IVN the peripheral route alone was used; 76% of patients who received peripheral IVN required only one fine-bore catheter.

Prolonged peripheral parenteral nutrition with an ultrafine cannula and low-osmolality feed

Peripheral parenteral nutrition is an attractive alternative to centrally delivered parenteral nutrition because it obviates the need for central venous cannulation and its attendant complications. Some 45 consecutive patients were fed peripherally using a 22-G polyurethane catheter and a fat-based, low-osmolality feed. Of these patients, 36 were fed for a median of 8.5 (range 3-31) days without peripheral vein thrombophlebitis (PVT). Seven patients developed PVT after a median of 6 (range 5-7) days. The cumulative daily risk of PVT was 0.016 episodes per day. These results suggest that prolonged (more than 7 days) problem-free peripheral parenteral nutrition is possible.

Randomised comparison of silicone versus Teflon cannulas for peripheral intravenous nutrition

The use of peripheral intravenous nutrition using standard Teflon cannulas is limited by a high incidence of thrombophlebitis, with resultant frequent line changes and compromised nutritional therapy. Fine-bore silicone catheters may reduce the incidence of thrombophlebitis; we prospectively compared the silicone catheter with a Teflon cannula in a randomised trial. Seventy-nine surgical patients were randomised to receive peripheral nutrition (10 g nitrogen; 1770 kcal; 650 mOsm/l) either via a Teflon cannula (18G, 4.4 cm long) or via a silicone catheter (23G, 15 cm long). Compared with the group randomised to a standard Teflon cannula, patients fed via a silicone catheter had a significant (P < 0.001) improvement in (a) median time to survival of the first catheter (125 h vs 48 h); (b) incidence of catheter reinsertions (13% vs 75%); and (c) incidence of thrombophlebitis (10% vs 48%). Delivery of a moderately hypertonic nutritional solution through a fine-bore silicone catheter is safe, durable and well tolerated, with a low incidence of complications relative to a Teflon cannula. An expanded role for this catheter in nutritional therapy is feasible, which may reduce the requirement for central venous parenteral nutrition.

The effect of dipeptide structure on dipeptide and amino acid clearance in rats

The kinetics of disappearance from the blood of GlyTyr, TyrArg, AlaTyr, TyrAla, GlnGly, GlyGln, GlnAla, and AlaGln and their constituent amino acids was assessed in anesthetized (pentabarbitone) Sprague-Dawley rats (n = 5 for each peptide). Catheters were inserted into both internal jugular veins. A bolus injection of dipeptide was administered into one catheter, and rapid blood samples were taken from the other catheter for measurement of dipeptide and amino acid concentrations. Kinetic parameters for the disappearance of dipeptides and of the amino acids released from the dipeptides from the blood were calculated using standard equations. All dipeptides were cleared rapidly from the blood (clearances ranged from 42.9 +/- 3.28 mL/min/kg body weight for GlyGln to 278 +/- 70.7 for GlnAla, mean +/- SD). Glutaminyl dipeptides with alanine or glycine in the C-terminal position or dipeptides with alanine in the N-terminal position had the greatest clearance values and the shortest half-lives (t1/2). There were significant differences (P < .001) in the volume of distribution of the dipeptides. Many dipeptides had volumes of distribution greater than the blood volume of the animals. The amino acids released from the dipeptides had a longer t1/2 (P < .001) than their parent dipeptides. The t1/2 and the weight-corrected area under the blood concentration-versus-time curve (AUC) of the same amino acid released from different dipeptides differed (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Peripheral versus central intravenous nutrition: comparison of two delivery systems

Forty-six surgical patients who required intravenous nutrition (IVN) were randomly allocated to receive complete IVN by a peripheral (n = 23) or central (n = 23) venous delivery system. The peripheral IVN system combined a fine-bore silicone catheter with lipid-based nutrient solutions whereas the central system used a conventional glucose-based nutrient regimen and a single-lumen central venous catheter. The incidence of catheter complications and the complication-free system function over time were compared. Problems of venous access were not observed with peripheral IVN but occurred with one central catheterization. Three patients with central venous catheters developed bacteraemia but only one incident was thought to be catheter related (bacterial translocation). There were no such episodes with peripheral IVN. Peripheral catheterization was not associated with infective phlebitis, although late-onset chemical phlebitis occurred on four occasions after a mean(s.e.m.) time of 22.8(6.1) days, representing a daily risk of phlebitis of 0.009. There was no significant difference in the probability of complication-free system function with time between peripheral and central IVN (P = 0.14). The fine-bore silicone catheter peripheral IVN delivery system resulted in long-term phlebitis-free infusion for periods that were similar to those of single-lumen central catheterization by life-table analysis.

Fine bore silicone rubber and polyurethane catheters for the delivery of complete intravenous nutrition via a peripheral vein

The aim of the study was to evaluate two fine bore catheters for the delivery of complete intravenous nutrition (IVN), of osmolality 1250 mosm/kg, via a peripheral vein. 50 patients were randomised to receive either a 23G silicone rubber catheter or 22G polyurethane catheter. The median duration of feeding was 9 days for silicone rubber catheters and 10 days for polyurethane catheters. Silicone rubber catheters developed complications significantly more frequently (44%) than polyurethane catheters (22%, p < 0.05). There was no significant difference in the median life span of the catheters removed because of complications, nor in the daily risk of thrombophlebitis. 92% of patients who were fed through a polyurethane catheter required only a single catheter for the duration of IVN. The peripheral venous route should be the first choice when the administration of IVN is considered for a period of less than 2 weeks.

First choice for total parenteral nutrition: the peripheral route

Historically, total parenteral nutrition (TPN) has been administered by the central venous route because of the rapid development of thrombophlebitis when TPN solutions are administered into peripheral veins. The insertion and placement of central venous catheters is, however, associated with morbidity and mortality and is the main cause of TPN-related complications. By avoiding central venous catheterization, TPN can be made safer. Current awareness about the pathophysiology of peripheral vein thrombophlebitis and the use of a number of techniques that prevent or delay onset of peripheral vein thrombophlebitis mean it is now possible to administer TPN via the peripheral route. These techniques and changes in the practice of TPN in recent years (eg, reduction of caloric loads and use of lipid emulsions) mean peripheral parenteral nutrition is a technique that is now applicable to the majority of hospitalized, nutritionally compromised patients for whom intravenous feeding is anticipated for less than 10 to 14 days.

Organ clearance of tyrosyl-arginine and its effect on amino acid metabolism in young sheep

In a long-term multiple-catheter sheep model (n = 5), organ clearance of the dipeptide tyrosyl-arginine (TyrArg) and its effects on interorgan amino acid metabolism were investigated. Clearance by hindlimb and splanchnic tissues was measured during infusion into the external iliac artery and superior mesenteric artery, respectively. The hindlimb, intestine, and total splanchnic region removed 32% +/- 9.2% (mean +/- SE), 23% +/- 15%, and 33% +/- 24%, respectively, of the amount of TyrArg infused. There was a large release of tyrosine and arginine when TyrArg was infused into either the hindlimb or intestine, which was quantitatively similar to the TyrArg taken up by these organs. However, across the total splanchnic region, the baseline influx of tyrosine and arginine was not altered by infusion of TyrArg. During either clearance study, only trace amounts of TyrArg or its constituent amino acids were excreted in urine. Infusion of TyrArg produced the following effects on interorgan amino acid metabolism: (1) a reduction in the initial efflux of phenylalanine, leucine, isoleucine, and valine from the hindlimb; (2) a reduction in net efflux of citrulline by the intestine and total splanchnic tissues; and (3) a reduction in efflux of arginine and uptake of citrulline from the kidney. In conclusion, we have shown that TyrArg is cleared from the bloodstream by hindlimb (predominantly muscle) and splanchnic tissues. These results indicate that TyrArg taken up by the hindlimb and intestine was hydrolyzed to its constituent amino acids, which were released quantitatively into the circulation. Of the tissues studied, only the liver appeared to use the amino acids liberated from hydrolysis of TyrArg.(ABSTRACT TRUNCATED AT 250 WORDS)

Peripheral parenteral nutrition: a preliminary report on its efficacy and safety

In this preliminary study of peripheral parenteral nutrition, we compared our first nine patients fed by this method with 21 patients fed by total parenteral nutrition during the same period. We found that peripheral parenteral nutrition was as effective as total parenteral nutrition in improving physiologic function (both skeletal and respiratory muscle function). We also found that by using the protocol described here thrombophlebitis was not a significant problem. Additional study is required to ascertain the exact incidence of this and other complications. We would advocate the greater use of peripheral parenteral nutrition in suitable patients and the use of this protocol for its administration.

Influence of catheter type on occurrence of thrombophlebitis during peripheral intravenous nutrition

To reduce the likelihood of thrombophlebitis during intravenous feeding through a peripheral vein, the osmolality of the solution is usually reduced by disproportionately raising the lipid content and lowering the carbohydrate, electrolyte, and aminoacid concentrations. The possibility that delivery system rather than feed is the main influence on the development of thrombophlebitis was examined in a randomised comparison of a fine-bore silicone catheter against a short 'Teflon' cannula. The nutrient solution given through a peripheral vein was a standard feed used for infusion into a central vein (osmolality 1250 mOsmol/kg, 13 g nitrogen, 200 g glucose [800 kcal], and lipid emulsion [1000 kcal]). 27 patients received the infusion through a fine-bore silicone rubber catheter (diameter 23 G, length 15 cm) and 23 through a teflon catheter (diameter 20 G, length 3.2 cm). The median duration of feeding was 5 days in each of the two groups. Thrombophlebitis developed in all patients in the teflon group but in only 2 (7%) of the silicone group. The first silicone catheter for a patient lasted a median of 128.5 h, compared with 40 h for the first teflon cannula (p less than 0.001). The results show that when a nutrient solution of osmolality 1250 mOsmol/kg is delivered through a peripheral vein with an ultrafine-bore silicone catheter, the risk of thrombophlebitis is low. For many patients intravenous feeding may thus be given through a peripheral instead of a central vein without compromising the nutritional adequacy of the feed.

Peripheral venous nutrition: the equal relevance of volume load and osmolarity in relation to phlebitis

This study aimed to investigate the peripheral vein tolerance for total parenteral nutrition (TPN) and to point out the factors which induce phlebitis. TPN was administered from 'all-in-one' bags. Five different types of TPN were investigated, wherein the amounts of amino-acids, dextrose, lipids, osmolarity and volume were varied. Type I (829 mOsm/l) was a low energy (1570 NPE kcal) nutritive mixture of 2425 ml with 9.5 g N. Type II (842 mOsm/l) was an intermediate energy (1800 NPE kcal) mixture of 2525 ml with 9.5 g N. Type III (860 mOsm/l) contained 1800 NPE kcal and 13.5 g N in 2775 ml. Type IV (790 mOsm/l) was only a dilution of Type III with 250 ml water. Type V (1044 mOsm/l) covered normal energy needs (2000 NPE kcal) and 13.5 g N in 2580 ml. All bags contained standard amounts of electrolytes, vitamines, trace elements and heparin (1.000 IE/l). The infusion site was not changed until phlebitis developed or oral feeding could be started. Type I, II, III and IV were given to at least 30 patients, and Type V to only 11 patients because of an unacceptable high phlebitis rate (91% after 2.8 days). The phlebitis rate for Type I, II, III and IV was 4%, 12%, 24% and 27% respectively after 48h increasing to 14%, 37%, 55% and 73% respectively after 14 days. The mean infusion time and phlebitis rate were related to each component of the nutritive mixture. A poor relation was found between the phlebitis rate and the amount of amino-acids, dextrose or lipid respectively. Both osmolarity (with variabl volume) and volume (with variable osmolarity) correlated poorly with the phlebitis rate (r = 0.37 and 0.29 respectively). However, the osmolarity rate, defined as the number of milliOsmols infused per hour, correlated well with the phlebitis rate (r = 0.95). Our results demonstrate that the peripheral route can be used as a practical alternative for central venous administration, if the osmolarity rate is limited.