Nutritional management of the frail elderly - presentchallenges and future treatments

PROF. TOMMY CEDERHOLM

DepartmentofGeriatricMedicine,856, HuddingeUniversityHospital,14186 Stockholm,Swedene-mail.·Tommy.Cederholm@ger.hs.sll.se

No short paper received.

E-3

Nurses' educational session getting started inTPNAims

• To examine how nurses can be involved in venousaccess and how the method of access determinessubsequent nursing protocols.

Vascular anatomy

PROF. ROBERT L. SCHELPER

• To support nurses wishing to become more involvedin venous access techniques.

AnatomicPathology,SUNYUpstateMedicalUniversity,Syracuse,NY13210, USAe-mail:schelper@upstate.edu

No short paper received.

Which device for which patient?

Helen Hamilton

NutritionNurseSpecialist,JohnRadcliffeHospital,OxfordOX39DU, Englande-mail.'Helen.Hamilton@orh.nhs.uk

Learning objectives

By the completion of the session the delegates will be

• able to describe the four main types of venous accessdevices (VADs) used for parenteral nutrition

• able to appreciate the importance of catheter size inrelation to individual patients

• able to assist the patient in making informeddecisions regarding their therapy needs.

• Following this session, delegates will be ableto aid the operator in the selection of the most

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appropriate eve and route for the patient'srequirements.

Key words: central venous catheter; central venousaccess; tunnelled catheters; parenteral nutrition; com­plications

Historical

Since 1952, when Aubaniac first reported performingpercutaneous central venous catheterization, the use

of central venous catheters (CVCs) has becomeroutine in the administration of parenteral nutrition(PN). The development of PN necessitated the need toprovide central venous access for prolonged periods oftime within a hospital setting and more recently in acommunity setting.

In 1973 Broviac and his colleagues designed a silasticcentral catheter, placed in a central vein, with the tipterminating in the right atrium. Six years later Hickman(1979) modified this design, increasing the internaldiameter, permitting multiple intravenous therapiesand blood sampling. Unique to this device was thetunneling of a segment of the catheter through thesubcutaneous tissue of the anterior or chest wall and anattached Dacron cuff to stimulate the growth of fibroustissue. These two features were designed to minimize therisk of bloodstream infection by providing a mechanicalbarrier between the skin surface and the intravascularCVe. Hickman's design has since become the model formodern CVCs.

As the diverse demands for CVCs increased, so didthe size of devices, and thus the associated complicationsbecame more apparent. Hoshal's (1971) early researchinvolving large CVCs, studied the rapid development ofCVC - related thrombus, and Pottecher's (1984) workinvolving CVC materials in relation to fibrin formationare fundamental but often forgotten factors when CVCsare inserted. Schelper's (1999) reference to the fragilityof venous anatomy (Fig. I) and the development ofthrombosis, when large CVCs are used without regardto the size of the patient's veins, are also importantconsiderations when selecting a CVC for PN, ifthrombosis and/or stenosis is to be avoided.

The early eighties heralded the arrival of a totallyimplanted central venous access system for both arterialand venous infusions (Neiderhuber 1982). This designattracted considerable interest with researchers who

NORMAL VENOUS STRUCTURE

ARE FBL 0FLOW

Figure I

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hoped the implanted system would compare favourablywith Hickman's (1979) tunneled CVC design.

Peripherally inserted central catheters (PICCs) havebeen used extensively in the acute care setting in theUSA since the 1970s and now account for a highproportion of all devices inserted for intermediate tolong term IV use, i.e. 4 weeks to 1 year (IntravenousNursing Society (INS).

PICCs, which are 50-60 ems in length, should not beconfused with midline catheters, which are only 20 em inlength, and are also placed peripherally in the superficialveins in the antecubital fossa or upper forearm.

Basic principles

Correct central venous access is defined as placement ofthe distal catheter tip in the lower third of the superiorvena cava (SYC) via either the subclavian, internaljugular or ante cubital veins.

This position of the CVC tip permits both infusionand aspiration from the turbulent central venouscirculation, avoiding central venous erosion by theCYC, which although uncommon can result in seriousinjury or death. This complication can be minimized bycareful selection of the percutaneous venous entry sitewith the left sided approach associated with greater riskof erosion and damage to the thoracic duct. A left- sidedapproach to CYC insertion, either via the internaljugular or subclavian vein (Scott, 1988) is also con­sidered to attract a higher risk of thrombosis, due to theangular route of the vessels in their route to the SVCand the inevitable contact of a large CVC with the veinwalls (Hamilton, 2002).

Conversely, midline catheters, in which the distal tip isnot advanced into the SYC, but terminates in a vesselin the upper arm. Whilst not providing central venousaccess, midline catheters may offer temporary venousaccess (5-7 d) for PN until central venous accessbecomes possible.

Therefore, accurate clinical assessment, prior to CVCinsertion, becomes an essential component in theprocess of selecting the appropriate vein (Hamiltonand Fermo, 1998) to meet the individual patient's needs.Patient safety clearly must be of paramount importanceand therefore the type of CVC and the route by whichcentral venous access is gained may often be determined,by clinical stability.

Haematological stability, i.e. agreed parameters of theclotting profile and platelet count will aid in ensuringhaemostasis during central venous cannulation. Reduc­tion or cessation of anticoagulant therapy, prior tocannulation of major vessels, may influence the methodof CYC insertion, with temporary venous access havingto suffice until haematological stability is resumed.

Elevated inflammatory markers may also influencethe type of CYC to be inserted. Dedicated, tunneled

or implanted CVCs are not advisable in this situation.However, a PICC could provide a safe option that maybe easily removed if symptoms of infection arose.

Assessment of respiratory function will provideinformation that may prevent deterioration in theoverall condition of the patient requiring central venousaccess. Respiratory difficulty or failure, as a result ofsepsis, sputum retention and/or electrolyte or fluidimbalance should influence an experienced operator toavoid the risks surrounding the insertion of a CVC viavessels in the neck or chest and consider placement of aPICC, until clinical stability is resumed.

Understanding the basic principles of central venousaccess and the relevance of clinical stability will aid theoperator and the nurse in dealing with the expandingnumber and types of vascular access devices currentlyavailable and select the safest, given each patients'clinical situation.

Device selection

Catheter choice is a key element in maintaining effectivecentral venous access. Catheters are now available in avariety of sizes, with an increasing number of lumens,cuffs, implanted ports impregnated materials and

Table 2 Four categories of central venous catheters

specialized valves. Device selection is important smceit must match the patient and therapy with the mostappropriate catheter. Ideally, single lumen CVCsdedicated purely for PN can provide not only efficientcentral venous access, but reduce the risk of infection.The selection of a CVC is based on input not only fromthe physician and the nurse, but from the caregiver andthe patient. Once all options are presented to the patienttheir preference will have a strong impact on the devicethat is selected. Specific factors that determine deviceselection for patients requiring PN include: (a) patientmobility, (b) clinical status, (c) anticipated duration oftherapy, (d) potential for further central venous access,(e) risk factors e.g thrombosis, pneumothorax, infection,stenosis (f) body image, (g) environment where PN is tobe administered, (h) lifestyle. Other considerations forCVC device selection include the evaluation of thepatient's available venous access, medical history andcurrent diagnosis.

Selection and placement of CVCs not only permitsdelivery of complex therapeutic agents but also im­proves the patient's quality of life if the correct CVC isselected. The choice of devices is extensive; howeverthese can be divided into four groups (Table 1).

Starting at the most generic level, CVCs are designedfor either short or long-term use. CVCs found inthe short-term category are typically viewed as

Catheter

Non tunneled.

Tunneled (Hickman,Broviac or GroshongCVCs) All utilizeDacron cuff withinsubcutaneoustunnel to secure CVC

Peripherally InsertedCentral Catheter(PICCs)

Implanted ports

Site

Usually internal jugular orsubclavian vein

Usually percutaneousinsertion via subclavianor jugular veins.

Percutaneous insertionvia antecubital vessels,preferably the basilicvein due to thedirect route of thevessel to the SVC

Usually via the cephalicvein with port placed insubcutaneous pocket onchest wall.

Indications

Acute, short-termduration PN

Long-term therapy/community based PN

PN ranging from severalweeks to monthsPossible to use in acuteand community care

Long-term PN

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Advantages

Economic; easily removed;exchanged over wire

Small diameter CVCavailable Possible bedsideinsertion Satisfactory forextended periodsSelf care by patientRepair facility if required

Reduced risk ofcomplications normallyassociated with thoracicinsertion. Repairpossible Nurseplacement possibleat patient'sbedside

Site carePatients able to swim onceinitial surgical scar healed.Good body image

Disadvantages

Patient self care difficultDressings difficult anduncomfortableInfection more likelyas non tunneledSerious insertionalcomplications possibleMay not be acceptable forsome patients whose bodyimage is importantSurgical removal necessaryand therefore additionalscarringThrombosis possibleif large device used via leftapproachSelf care can bedifficult Routine flushingessential, bloodsampling notalways possiblePhlebitis/infectionpossible unlessprecautions ofapplying heattakenMay be unsuitable for trueneedlephobic patients.Needle access required anddisplacement canresult inextravasationSurgical removalnecessary

non-tunneled, percutaneously placed CVCs, usuallyinserted via the internal jugular (11) vein, often followinga surgical procedure. These CVCs are normally ade­quate for 5-7 days, if dedicated purely for PN, until atunneled and cuffed CVC, if the clinical stability of thepatient can be guaranteed.

Included in the percutaneously placed category arePICCs, which have both short- and long-term applica­tions, if venous access is suitable and the clinicalsituation appropriate. PICCs can be particularly usefulin the unstable patient where gaining central venousaccess via the chest may compromise patient stability.Longer-term use of PICCs may also be an option forcertain patients requiring community based PN whomay prefer this type of venous access.

Small diameter, tunneled CVCs and implanted sub­cutaneous ports provide long-term venous access forpatients requiring prolonged PN. By selecting thesmallest device and optimizing CVC tip position (lowerthird SVC) will aid in the reduction of damage to thevein walls and reduce the risk of fibrin sheath formationand thrombosis. An awareness of the osmolality and pHof PN (Ryder, 1996) should also encourage correctpositioning of the CVC tip to provide appropriatehaemodilution and safe administration of PN.

Once seen as a last resort, or reserved for the criticallyill, the use of CVCs for PN has provided an increasingnumber of patients with central venous access not onlyin hospital but also in outpatient settings. PN adminis­tered within the hospital and community setting isexpanding daily and places increasing demands onnurses in relation to patient preparation and assessment(Kayley, 2000). However, although the use of centralvenous access has facilitated innovative patient care, ithas also precipitated many complications arising frominappropriate catheter selection. Therefore, nurses car­ing for patients undergoing this form of venous accessshould not become complacent as a number of seriousrisks and complications, including death, can occur bothduring and after the procedure if the incorrect device orroute is chosen (Drewett, 2000).

References

Aubaniac R. L'injection intraveineuse sons-claviculaire. Advantages ettechnique. Press Med 1952; 60: 1456

Broviac J W, Cole J J, Scribner B H. A silicone rubber atrial catheterfor prolonged parenteral alimentation. Surgery. Gynecology andObstetrics 1973; 136: 602-606

Drewett S R. Complications of central venous catheters: nursing care.Br J Nurs 2000; 9(8): 466-478

Hamilton H. Fermo K. Assessment of patients requiring IV therapyvia a central venous route. Br J Nur 1998; 7(8): 451-460

Hickman R 0, Buckner C D, Clift R A, Sanders J E, Stewart P,Thomas E D. A modified right atrial catheter for access to thevenous system in marrow transplant recipients. Surgery,Gynecology and Obstetrics 1979; 148: 871-875

Hoshal V L, Ause R G, Hoskins P A. Fibrin sleeve formation onindwelling subclavian central venous catheters. Arch of Surgery1971; 102: 353-358

Neiderhuber J E, Ensminger W, Gyves J W, Liepman M, Doan K,Cozzi E. Totally implanted venous and arterial access system toreplace external catheters in cancer treatment. Surgery 1982; 92:706-712

Pottecher T, Forrler M, Picardat P, Krause D, Bellocq J P, Otteni J C.Thrombogenicity of central venous catheters: prospective study ofpolyethylene, silicone and polyurethane catheters withphlebography or post-mortem examination. Eur J Anaest 1984; I:361-365

Schelper R. Endothelium and venous access. Educational session. In:A New Dawn of Opportunity, National Association of VascularAccess Networks (NAVAN) 13th Annual Conference, September:68-76, NAVAN publication. Draper. UT, USA

Further reading

Baranowski L. Central Venous Access Devices: Current technologies,uses and management strategies. Journal of Intravenous Nursing1993; 16(3) May/June: 167-194

Bern M M, Lokich J J, Wallach S R, Bothe A, Benotti P N, Arkin C F,Greco F A, Huberman M, Moore C. Very low doses of warfarincan prevent thrombosis in central venous catheters. Annals ofInternal Medicine 1990; 112: 423-428

Hamilton H. Should the internal jugular or subclavian vein be utilizedin long term central venous access: a review of the literature.Unpublished dissertation, 2002, Brookes University, Oxford.

Krzywda EA. Central Venous Access - Catheters, Technology andPhysiology. MEDSURG Nursing, June 1998; 7(3): 132-141

Ryder M. Device selection: A critical strategy in the reduction ofcatheter-related complications. Nutrition 1996; 12: 143-145

Management and complications

SARAH DREWETT

ClinicalNurseSpecialist

No short paper received.

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