Publisher's copy made available with the permission of the publisher © 1997 Australian Society of Anaesthetists "Because of a printer's error in the December 1996 issue of Anaesthesia and Intensive Care (Vol. 24, No. 6, p. 708, Figure 4) this paper is reprinted here in its entirety and in its correct form"--cf. p.42Tissue irritation, as evidenced by phlebitis, associated with Optiva™ (Johnson & Johnson Medical) and Insyte™ (Becton Dickinson) polyurethane cannulae was studied. The integrity of the cannulae on removal, the incidence of infection at the cannula site and the factors which influence phlebitis were also examined. One thousand and eight patients had a polyurethane cannula placed for induction of anaesthesia for cardiac surgery. After surgery, the cannula was examined every 24 hours. If evidence of phlebitis occurred, the cannula was removed and sent for culture. All remaining cannulae were removed at 72 hours and the site examined daily for a further three days. There were 503 Optiva™ and 505 Insyte™ cannulae studied. The distributions between the two cannulae with respect to patient characteristics, gauge of cannula, number of attempts and difficulty of insertion, cannula site and anaesthetist inserting were similar. The early removal rate for both groups was 47%. Overall phlebitis rate with Optiva™ was 31% and Insyte™ 33%. This difference is not statistically significant. The cumulative phlebitis rate increased with time but did not differ between the two types of cannulae. Minor tip distortion or shaft kinking of the cannulae occurred in 16.2% of Optiva™ and 23.5% of Insyte™. This difference is statistically significant and may relate to the slightly more acute taper at the Optiva™ cannula tip. Both cannulae were similar in clinical performance.W.J. Russell, S. Micik, S. Gourd, H. Mackay, S. Wrigh

Gourd, S.

Mackay, H.

Micik, S.

Russell, W.

Wright, S.

Anaesthesia and Intensive Care

English

Adelaide Research & Scholarship

Anaesthesia and Intensive Care, Vol. 25, No. 1, February 1997Anaesth Intensive Care 1997; 25: 42-47EquipmentA Prospective Clinical Comparison of Two IntravenousPolyurethane Cannulae#W. J. RUSSELL*, S. MICIK†, S. GOURD‡, H. MACKAY§, S. WRIGHT**Departments of Anaesthesia and Intensive Care, and Cardiothoracic Services, Royal Adelaide Hospital, Adelaide, S.A.SUMMARYTissue irritation, as evidenced by phlebitis, associated with Optiva™ (Johnson & Johnson Medical) and Insyte™(Becton Dickinson) polyurethane cannulae was studied. The integrity of the cannulae on removal, the incidence ofinfection at the cannula site and the factors which influence phlebitis were also examined. One thousand and eight patients had a polyurethane cannula placed for induction of anaesthesia for cardiacsurgery. After surgery, the cannula was examined every 24 hours. If evidence of phlebitis occurred, the cannula wasremoved and sent for culture. All remaining cannulae were removed at 72 hours and the site examined daily for afurther three days. There were 503 Optiva™ and 505 Insyte™ cannulae studied. The distributions between the two cannulae withrespect to patient characteristics, gauge of cannula, number of attempts and difficulty of insertion, cannula site andanaesthetist inserting were similar. The early removal rate for both groups was 47%. Overall phlebitis rate with Optiva™ was 31% and Insyte™ 33%. This difference is not statistically significant. Thecumulative phlebitis rate increased with time but did not differ between the two types of cannulae. Minor tip distortion or shaft kinking of the cannulae occurred in 16.2% of Optiva™ and 23.5% of Insyte™. Thisdifference is statistically significant and may relate to the slightly more acute taper at the Optiva™ cannula tip. Bothcannulae were similar in clinical performance.Key Words: EQUIPMENT: polyurethane cannulae; ANAESTHETIC TECHNIQUES: intravenous cannulation;COMPLICATIONS: phlebitisPhlebitis is a well-recognized complication of intra-venous therapy. Several factors have been shown tocontribute to phlebitis. Maki and Ringer reported arisk of phlebitis over 50% after four days insertion1and identified patient and other factors which con-tributed to the phlebitis rate. Female patients werefound to be 1.9 times more likely to get phlebitis andinsertion on the forearm was more likely to result inphlebitis than insertion into the hand or wrist. Theyalso reported that the catheter material affected theincidence of phlebitis. A cannula made from Teflon™was 1.37 times more likely after a few days to cause phlebitis than one made with polyurethane(Vialon™). Larsson and colleagues suggested thatthis might be explained by chemical leeching from thedifferent cannula materials2. A difference in phlebitisrates for the two materials was supported by a studyby McKee et al in 191 patients. They found a phlebitisrate at 72 hours of 31% for Vialon™ and a 51% ratefor Teflon™3. A larger study of 645 cannulae used forinduction of anaesthesia by Gaukroger et al but whichremained in for up to four days also found thatVialon™ had only 54% of the phlebitis risk ofTeflon™4. However, a double-blind randomized con-trolled comparison of both types of cannulae at theCentral Middlesex Hospital in London failed to findany difference in phlebitis rate over five days5.# Because of a printer’s error in the December 1996 issue ofAnaesthesia and Intensive Care (Vol. 24, No. 6, p. 708, Figure4), this paper is reprinted here in its entirety and in its correctform*F.R.C.A., F.A.N.Z.C.A., Ph.D., Director, Research and Development,Department of Anaesthesia and Intensive Care.†B.N.(Flinders), C.N., Department of Cardiothoracic Services.‡R.N., Clinical Nurse, Department of Cardiothoracic Services.§B.N.(Flinders), Clinical Nurse, Department of Cardiothoracic Services.**R.N., Clinical Nurse, Department of Cardiothoracic Services.Address for Reprints: Dr W. J. Russell, Department of Anaesthesia andIntensive Care, Royal Adelaide Hospital, North Terrace, S.A. 5000.Accepted for publication on August 8, 1996.43The difference in findings is difficult to explain.One possible explanation is the difference in treat-ment of the Teflon™ surface. All the positive studieswere comparing the Insyte™ made of Vialon™ byBecton Dickinson with the Jelco™ made of Teflon™by Johnson & Johnson Medical. The negative studyused a Teflon™ Vasculon™ cannula made by Viggo-Spectramed. The microscopic surface properties ofsimilar material can be different. A study by Tebbs etal of polyurethane catheters showed that the smooth-ness of the surface differed substantially6 and thesmoother surfaces were associated with a lower bac-terial colonization after one hour of incubation. Thuseven if cannulae are made of the same material, otherfactors may still create a significant difference in theclinical phlebitis rate. Although the new Optiva™cannula is made of polyurethane, the cannula is trans-parent and claimed by the company to be an improve-ment on the Vialon™ polyurethane. In addition, theinserting needle is of a different profile, being back-sharpened and it is claimed that about a 20-30%smaller force is required for needle and cannulainsertion. This could alter the tissue damage oninsertion.As the major concern for most clinicians is howlong they can use an intravenous cannula, a trial wasdesigned to prospectively compare the two clinicallyavailable polyurethane cannulae, Optiva™ fromJohnson & Johnson Medical and Insyte™ fromBecton Dickinson with particular reference tophlebitis, which is the most common limiting factorfor long term use.METHODSPatients undergoing cardiac surgery were randomlyallocated to have their induction through either anOptiva™ or Insyte™ polyurethane cannula. Randomi-zation was determined by a table of random numbers.All patients were greater than 18 years old and gaveinformed consent as approved by the Royal AdelaideHospital Ethics Committee.Patients were excluded if informed consent was notpossible or the patient refused. They were alsoexcluded if there was evidence of infection, or thecannulae were not suitable for the patient.The chosen cannula was inserted by an experiencedanaesthetist and then connected to an infusion setrunning a balanced electrolyte solution. This set wasused for the induction of anaesthesia and the admini-stration of drugs and fluids during the operation.After the patient was in the cardiac intensive care andstable so that this IV line was no longer required, thecannula was capped and flushed with heparin saline.This cannula then remained in for a total of threedays, after which it was removed and the siteobserved daily for a further three days for evidence ofphlebitis or infection. After capping, an injectionthrough the cannula of heparin saline flushing solu-tion (50 units in 5 ml) was ordered eight hourly prn.Daily monitoring of the cannula site was per-formed by one of the three study nurses. The cannulasite was assessed for any signs of phlebitis such aserythema, oedema, pain or tenderness, streak forma-tion, a palpable venous cord or any exudate. If thisoccurred within the three days, the cannula wasremoved. If evidence of phlebitis occurred at any timeduring the six days observation, the site was swabbedand the swab sent for culture. In addition, the degreeof phlebitis was graded as mild (pain and/orerythema), moderate (oedema and/or streaking alongvein) or severe (a palpable venous cord and/orexudate at cannula site). If a patient had more thanone symptom or sign, then the highest appropriatecategory was used. This scoring was done at the timethe cannula was removed or during the subsequent post-decannulation observation and the maximumreaction scored.Immediately after removal, the cannula wasexamined macroscopically and any damage or defor-mation recorded.Demographic data was collected on the patientsand a record was kept of all drugs administered dur-ing the three days the cannula was in. In addition,data about the insertion was also recorded. Thisincluded the anaesthetists, the size of the cannula, thesite of insertion, and the ease of insertion.Statistical analysis of the cannula duration was bysurvival analysis using a Kaplan-Meier estimation andmultivariate modelling was done using a Cox propor-tional hazards model with co-variates. The initialvariables for the stepwise regression were chosen by at-test, Chi square, or Wilcoxon as appropriate with athreshold P value of 0.2.RESULTSOne thousand and eight patients had cannulaeinserted for more than 12 hours. Five hundred andthree received Optiva™ cannulae and 505 receivedInsyte™ cannulae. These two groups are wellmatched with respect to age, sex, weight, diabetes,preoperative white cell count and preoperative bloodsugar (Table 1). Similarly the two groups were wellmatched for factors relating to the insertion of theCOMPARISON OF POLYURETHANE CANNULAEAnaesthesia and Intensive Care, Vol. 25, No. 1, February 199744 W. J. RUSSELL, S. MICIK ET ALAnaesthesia and Intensive Care, Vol. 25, No. 1, February 1997TABLE 1All Patients (n=1008)Patient Characteristic Optiva™ Insyte™(n=503) (n=505)Age (years) Mean 61.5 61.2SD 10.7 10.9Min-Max 18-85 26-85Sex Male 387 (77%) 384 (76%)Female 116 (23%) 121 (24%)Weight (kg) Mean 77.0 76.9SD 13.8 12.8Min-Max 40-121 40-121History of diabetes Yes 58 (12%) 80 (16%)No 445 (88%) 425 (84%)White cell count (x103) Mean 7.4 7.5SD 2.0 2.2Min-Max 1.1-22 1.1-20.5Blood sugar level(mmol/l) Mean 6.3 6.5SD 2.7 3.0Min-Max 1.5-19.7 1.6-23.0TABLE 2All Patients (n=1008)Cannula Characteristics Optiva™ Insyte™(n=503) (n=505)Cannula gauge 14 ga 95 (19%) 100 (20%)16 ga 379 (75%) 370 (73%)18 ga 29 (6%) 35 (7%)Cannula site (arm) Left 464 (92%) 464 (92%)Right 39 (8%) 41 (8%)Cannula site (position) Upper Arm 1 (0.2%) 1 (0.2%)Antecubital Fossa 80 (16%) 74 (15%)Forearm 143 (28%) 161 (32%)Wrist 134 (27%) 137 (27%)Hand 145 (29%) 132 (26%)Degree ofdifficulty Easy 440 (88%) 434 (86%)Some difficulty 5 (1%) 3 (1%)Extreme difficulty 58 (11%) 68 (13%)Number of attempts 1 445 (88%) 445 (88%)2 47 (9%) 51 (10%)3 8 (2%) 9 (2%)>4 3 (0.6%) 0 (0%)Anaesthetist 1 92 (18%) 113 (22%)2 15 (3%) 12 (2%)3 123 (24%) 101 (20%)4 28 (6%) 38 (8%)5 37 (7%) 35 (7%)6 3 (0.6%) 3 (0.6%)7 78 (15%) 67 (13%)8 38 (8%) 37 (7%)9 64 (13%) 74 (15%)10 27 (5%) 23 (5%)TABLE 3All Patients (n=1008)Cannula Removal Optiva™ Insyte™(n=503) (n=505)Cannula-related 185 (37%) 186 (37%)Phlebitis 111 (22%) 124 (25%)Infiltration 30 (6%) 26 (5%)Leakage 31 (6%) 26 (5%)Other 13 (3%) 10 (2%)Non cannula-related 318 (63%) 319 (63%)End of Trial 264 (53%) 266 (53%)Dislodgement 32 (6%) 28 (6%)Other 22 (4%) 25 (5%)FIGURE 1: The survival of the two types of cannulae for the free-dom from phlebitis at the cannula or cannula site. The Optiva™survival line is shown as solid dots joined by a continuous line. Thesurvival curves have been extended beyond day 6 for clarity. TheInsyte™ is shown as a solid diamond joined by a dashed line.Although there is a better survival of the Optiva™ cannulae, this isnot statistically significant.TABLE 4Variable Coeff Std Hazards 95% CI P valueError RatioEsmolol(Yes:No) 0.66 0.23 1.94 1.24-3.05 0.0039Site of cannula(Antecubital:Wrist) 0.03 0.12 1.03 0.81-1.30 0.8096(Forearm:Wrist) 0.18 0.09 1.20 1.00-1.43 0.0414(Hand:Wrist) –0.15 0.10 0.86 0.70-1.05 0.1357Nurse assessor1:3 0.20 0.08 1.22 1.05-1.42 0.00882:3 0.04 0.08 1.04 0.89-1.21 0.6499cannula (Table 2).In both groups 47% of the cannulae were removedbefore the three days had expired. The commonestreason for removal was phlebitis (Optiva™ 22% andInsyte™ 25%); the difference is not significant (P=0.37 Fisher). A complete list is given in Table 3.With both cannulae there was a progressiveincrease in phlebitis while the cannula remained inand some continued phlebitis in the three days afterremoval (Figure 1). However, although the Optiva™cannulae had a slightly lower progressive incidence,this difference was not statistically significant. Theadjusted survival for Optiva™ after six days was esti-mated at 68.7% (95% CI 64.6-72.8) and for Insyte™was 67.2% (95% CI 63.1-71.3).Only three factors were identified as influencingthe incidence of phlebitis with the Cox proportionalhazards model. These were: the use of esmolol, thesite of the cannulation and the nurse observer identi-fying phlebitis (Table 4). The hazard ratio expressesthe increased risk of the factor being present, e.g.cannulation on the forearm increased the risk ofphlebitis 20% (confidence interval 0-43%, P=0.04).The severity of phlebitis with each type of cannulawas also assessed. At each grade the level of phlebitiswas similar with both cannulae (P=0.41 Chi square,Figure 2). In addition, the type of reaction was alsosimilar (Figure 3). None of these reaction differencesbetween cannulae was statistically significant (allcategories P>0.02).When the cannulae were removed, the shaft andtip of every cannula were examined. Evidence ofdamage was noted in 80 Optiva™ cannulae and 120Insyte™ cannulae (Figure 4). Shaft kinking occurredto both types in about equal frequency (6.1% and8.2% respectively). However, the incidence of tipdamage or distortion with Insyte™ was significantlygreater than with Optiva™ (P=0.0001 Fisher).DISCUSSIONThe two cannulae groups are very well matched forthe characteristics examined and gives grounds forconfidence in the randomization. There was nostatistically significant difference in phlebitis betweenthe two cannulae three days after insertion and in thesubsequent three days of observation. The incidenceof phlebitis over the six days was 31% with theOptiva™ cannula and 33% with the Insyte™. With1008 patients and assuming an α =0.20, this trial hasan estimated power of 87% to detect a real differenceof 5%. As the difference in phlebitis seen was 2% it isunlikely that a clinically significant difference in thesetwo cannulae has been missed.Although 22% of the Optiva™ and 25% of theInsyte™ were removed because phlebitis was identi-fied, a further 15% of Optiva™ and 12% of Insyte™cannulae were removed early for other reasons. Thesurvival incidence at day 3 adjusted for the non-phlebitis removals is 75.3% (95% confidence inter-vals 71.5-79.1) for Optiva™ and 73.1% (95% CI 69.2-77.0) for Insyte™ respectively. At day 6 the survival45 COMPARISON OF POLYURETHANE CANNULAEAnaesthesia and Intensive Care, Vol. 25, No. 1, February 1997FIGURE 2: Comparison of the incidence and degree of phlebitis found in the Optiva™ and Insyte™ cannulae. Most cannulae showed nophlebitis but in those which did the grades of severity were equally distributed between the two types.46 W. J. RUSSELL, S. MICIK ET AL(i.e. non-phlebitis rate) is 68.7% (95% confidenceintervals 64.6-72.8) for Optiva™ and 67.2% (95% CI63.1-71.3) for Insyte™. This shows that in both groupsthere was about 10% additional phlebitis over thethree days after removal. The first day post-removalhowever, has about 50% of the additional phlebitisand if the second day is included this will cover over80% of the delayed phlebitis. Thus this pattern isfaster than an exponential decay and it can bereasonably extrapolated that over 90% of the addi-Anaesthesia and Intensive Care, Vol. 25, No. 1, February 1997FIGURE 4: Comparison of the type of cannula damage found with the Optiva™ and Insyte™ cannulae. Tip damage was more frequent withthe Insyte™ (P=0.0001). However, this did not appear to affect the incidence of clinical phlebitis.FIGURE 3: Comparison of the type and frequency of phlebitis found in the Optiva™ and Insyte™ cannulae. Most cannulae showed nophlebitis but in those which did the patterns of the phlebitic response were equally distributed between the two types.tional change will be observed within the three days.The Cox’s proportional hazard model to identifythe major factors in phlebitis in this study found threeparameters of interest. The use of esmolol isidentified as the most significant factor. This mustremain in doubt as the number of patients receivingesmolol was very small. However esmolol is wellknown to provoke histamine release so that aphlebitic enhancement may be expected. The site ofcannulation is of significance as the use of the midforearm veins is common. Possibly in the cardiacscenario when patients are cold and vasoconstrictedthese veins are experiencing an unusually low flow asthey tend to be superficial.It appears that in spite of differences in appearanceand needle profile, both the Optiva™ and the Insyte™cannulae have a similar risk of phlebitis in clinical useand similar survival expectations.ACKNOWLEDGEMENTThe financial support of Johnson & JohnsonResearch Pty Limited is gratefully acknowledged.Help with data preparation by Mrs Julie Jones and DrPeter Spencer and assistance with statistical analysisby Mr Stephen Halpin of Datapharm Australia is alsoacknowledged with thanks.REFERENCES1. Maki D, Ringer M. Risk factors for infusion-related phlebitiswith small peripheral venous catheters. Ann Intern Med 1991;114:845-854.2. Larsson N, Stenberg K, Linder L-E, Curelaru L. Cannulathrombophlebitis: a study in volunteers comparing polytetra-fluorethylene, polyurethane, and polyamide-ether-elastomercannulae. Acta Anaesthesiol Scand 1989; 33:223-231.3. McKee JM, Shell JA, Warren TA, Campbell VP. Complicationsof intravenous therapy: a randomized prospective study—Vialon vs. Teflon. J Intravenous Nursing 1989; 12:288-295.4. Gaukroger PB, Roberts JG, Manners TA. InfusionThrombophlebitis: a prospective comparison of 645 Vialon™and Teflon™ cannulae in anaesthetic and postoperative use.Anaesth Intensive Care 1988; 16:265-271.5. Payne-James JJ., Rana SK, Rogers J, McSwiggan D, Bray MJ,Silk DBA. Development of thrombophlebitis in peripheral veinswith Vialon and PTFE-Teflon cannulas: a double-blind ran-domised controlled trial. Ann R Coll Surg Engl 1991; 73:322-325.6. Tebbs SE, Sawyer A, Elliott TSJ. Influence of surface mor-phology on in vitro bacterial adherence to central venous-catheters. Br J Anaesth 1994; 72:587-591.47 COMPARISON OF POLYURETHANE CANNULAEAnaesthesia and Intensive Care, Vol. 25, No. 1, February 1997

Cannula thrombophlebitis: a study in volunteers comparing polytetrafluorethylene, polyurethane, and polyamide-ether-elastomer cannulae. Acta Anaesthesiol Scand

Complications of intravenous therapy: a randomized prospective study— Vialon vs.

Development of thrombophlebitis in peripheral veins with Vialon and PTFE-Teflon cannulas: a double-blind randomised controlled trial. Ann R Coll Surg Engl

Influence of surface morphology on in vitro bacterial adherence to central venouscatheters.

Infusion Thrombophlebitis: a prospective comparison of 645 Vialon™ and Teflon™ cannulae in anaesthetic and postoperative use. Anaesth Intensive Care

Risk factors for infusion-related phlebitis with small peripheral venous catheters. Ann Intern Med

A prospective clinical comparison of two intravenous polyurethane cannulae

A prospective clinical comparison of two intravenous polyurethane cannulae

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