(4) Cover gauze with tape.

(5) Label dressing with initials and date.

(6) Secure IV tubing with tape to prevent tension

on the center (a stress loop can decrease tension

on the catheter).

F. Care of the Catheter When Not in Use for

Continuous Infusion

Indications

To maintain patency and prevent clotting of the catheter

when the line is used intermittently. Only large-bore catheters (2.5 Fr or larger) may be kept patent by this technique.

PICC lines that are 2 Fr or smaller tend to clot easily if continuous infusions are interrupted.

Equipment

1. 3 mL of heparin–saline solution (10 unit Heparin /mL)

in a 10-mL syringe (follow manufacturer’s guidelines

for syringe sizes)

2. Alcohol wipes

3. Catheter clamps (must have no teeth or be padded), or

use clamp provided on catheter (Fig. 32.10)

4. Clean gloves

5. IV injection cap (needleless is recommended)

Chapter 32 ■ Central Venous Catheterization 207

Technique

1. Converting to a heparin lock

a. Wash hands thoroughly.

b. Don clean or sterile gloves.

c. Prepare sterile work area.

d. Using aseptic technique, open sterile injection cap

package and prefill injection cap with heparinized

saline.

e. Clean the outside of the hub–IV tubing connection

with an antiseptic such as alcohol wipes. Work outward in both directions. Allow to dry.

f. Clamp catheter with padded hemostat, or close

catheter clamp.

g. Holding hub with alcohol swab, disconnect catheter

hub from IV tubing.

h. Connect preflushed injection cap into hub of catheter (gently flushing during connecting can prevent

air from entering catheter).

i. Release clamp and flush line with 1 to 3 mL of heparinized saline (depending on size of catheter).

Fig. 32.13. Occlusive dressing for a central venous

line using presplit gauze. A: Placing split gauze over

the skin entry site. B: Covering split gauze and the

catheter with sterile gauze. Entire dressing is then covered with adhesive tape or clear dressing.

j. Reclamp catheter while plunger of heparin syringe

is depressed to prevent blood from backing into

catheter (positive pressure).

k. Secure catheter and tape to chest or abdomen.

l. Flush catheter with heparinized solution every 6 to

12 hours (per institution policy).

2. Flushing catheters

Equipment is same as for heparin lock.

a. Wash hands thoroughly.

b. Put on gloves and prepare sterile work area.

c. Prepare IV injection cap with antiseptic solution.

Allow to dry.

d. If injection cap is part of a needleless system (recommended), connect flush syringe to cap. If the cap is

not a needleless device, insert needle into IV catheter

plug. Always use a 1-inch or smaller needle. A longer

needle can puncture the catheter.

e. Unclamp catheter and slowly inject 1 to 2 mL of heparinized saline (depending on catheter size). Reclamp

catheter while injecting solution to prevent blood

A

B

 

206 Section V ■ Vascular Access

E. Sterile Dressing for Surgically Placed

Central Venous Lines

Routine changing of central venous catheter dressings

depends on the type of dressing. Transparent dressings should

be changed at least every 7 days, and gauze dressings every 2

days. All dressings should be changed when damp, loose, or

soiled (2).

Equipment

Strict sterile technique is used for all central line dressings.

1. Antiseptic skin prep solution: Per institutional policy (e.g.,

10% povidone–iodine or 0.5% chlorhexidine solution)

2. Sterile gloves, mask, cap, and sterile gown (optional)

3. Scissors (optional)

4. Cotton-tipped applicator

5. 4- × 4-inch sterile gauze square

6. Dressing of choice

a. Semipermeable transparent dressing

b. Sterile 2- × 2-inch gauze squares or presplit 2- ×

2-cm gauze dressing

7. Normal saline or sterile water

8. Adhesive tape (if sterile tape not available, use fresh

unused roll)

Precautions

1. Procedure should be undertaken by trained personnel.

2. Ensure that all personnel wear masks if within 3 ft

radius of sterile area.

3. Use strict aseptic technique.

4. Remove dressing with care, to avoid cutting or dislodging catheter.

5. If it is necessary to clamp the catheter, close the clamp

on the catheter according to the manufacturer’s directions. If the catheter does not have a clamp, use a

rubber-shod clamp. Never place a clamp directly on

the catheter.

6. Never advance a dislodged catheter into the patient.

7. Do not place adhesive tape on silicone tubing because

this may occlude or damage the catheter.

8. Do not routinely apply prophylactic topical antimicrobial or antiseptic ointment at the insertion site because

of the potential for promoting fungal infections and

antimicrobial resistance (2).

Technique

When a subcutaneous tunnel is used, occlusive dressing

should be applied to both the cutdown site and the catheter

exit site. The dressing on the exit site can be removed after

48 hours if there is no oozing.

1. Restrain patient appropriately, utilizing nonpharmacologic comfort measures.

2. Put on head cover and mask.

3. Scrub as for major procedure.

4. Put on gown and gloves.

5. Prepare sterile work area, using “no-touch” technique.

6. Remove old dressing and discard.

7. Inspect catheter site carefully (Table 32.4).

8. Culture site if there is drainage or it appears inflamed.

9. If area around catheter is contaminated with dried

blood or drainage, clean with diluted hydrogen peroxide/sterile water solution (1:1).

10. Remove gloves. Don sterile gloves.

11. Cleanse area with antiseptic solution, starting at catheter site and working outward in circular motion for 2 to

4 cm. Repeat twice. Allow area to dry.

12. Remove antiseptic with sterile water or saline gauze

and allow to dry.

13. Apply dressing of choice.

a. Clear, adhesive, hypoallergenic, transparent dressing allows for continuous inspection of catheter

insertion site, and is preferred (Fig. 32.10).

(1) If necessary, cut dressing to desired size.

(2) Anchor dressing to skin above catheter skin

entry site so that the point of skin entry is at the

center of the dressing.

(3) Remove remainder of adhesive backing while

applying dressing smoothly over site.

b. Occlusive gauze dressing

(1) Cut gauze halfway across, or use presplit gauze.

Place around catheter, as shown in Fig. 32.13.

(2) Cover remainder of external catheter length

(not hub) with sterile gauze.

(3) If sterile tape is not available, discard outer layer

of tape on roll.

 

Chapter 32 ■ Central Venous Catheterization 205

p. Visualize catheter entering common femoral vein to

ensure cephalad direction of catheter.

q. Obtain radiograph(s) to confirm position in inferior

vena cava, once estimated length is inserted (radiographic contrast material may be required).

r. Ligate vessel with caudad suture, and tie down

cephalad suture without occluding catheter.

s. Check for easy backflow of blood in catheter.

t. Flush catheter with 2.5 to 3 mL of heparinized

saline. If catheter is capped, while infant is transferred from operating room to intensive care unit,

clamp catheter while plunger of heparin syringe is

moving forward to ensure positive pressure in line to

prevent backflow and clotting of blood.

u. Close groin wound with subcuticular 5-0 absorbable

suture, taking care not to penetrate catheter with

needle.

v. Secure the catheter to the skin with at least one

nylon suture to hold it until the cuff has created

enough tissue ingrowth.

w. Cover with dressing of choice.

Fig. 32.11. Insertion of a catheter into the common facial vein. Incision is below

the angle of the mandible at the level of the hyoid bone. The facial vein is ligated at

the junction of the anterior and posterior tributaries. Alternatively, the subcutaneous tunnel may be made with a catheter exit site on the anterior chest wall. Inset:

The catheter is looped in the neck wound to “dampen” the effect of head movement. (Reproduced from Zumbro GL Jr, Mullin MJ, Nelson TG. Catheter placement in infants needing total parenteral nutrition utilizing common facial vein.

Arch Surg. 1971;102:71, with permission of American Medical Association.)

Fig. 32.12. Anatomic view of the site of incision for proximal

saphenous vein cutdown with underlying femoral triangle.

 

204 Section V ■ Vascular Access

m.Cut the catheter length to the premeasured distance

between the neck incision and a point midway

between the center of the nipple line and the suprasternal notch.

n. Perform transverse venotomy (Fig. 32.8).

FOR EXTERNAL JUGULAR OR FACIAL VEIN

(1) Tie cephalad-venous ligature, and exert traction

on both ligatures in opposite directions with aid

of appropriately prepared assistant.

(2) Make short, transverse incision in anterior wall

of vein, and enlarge gently by inserting and

spreading tips of fine vascular forceps.

FOR INTERNAL JUGULAR VEIN

(3) To avoid ligation of the vessel, use purse-string

suture of 6-0 polypropylene, placed in vessel

wall around point of catheter entrance.

(4) Make incision in vessel as for external jugular vein.

o. Bevel intravascular end of catheter (optional).

p. Grasp catheter gently with blunt nontoothed tissue

forceps, introduce catheter tip, and insert into the

vein.

q. Leave loop of catheter in neck wound to dampen

effect of head movement (Fig. 32.11).

r. Close wound with subcuticular 5-0 absorbable

suture, taking care not to penetrate the catheter.

s. Secure the catheter to the skin with at least one

nylon suture to hold it until the cuff has created

enough tissue ingrowth.

t. Use selected method for fixation and dressing.

2. Proximal saphenous vein cutdown

a. Scrub and prepare as for major procedure.

b. Prepare as for cutdown on jugular vein. Make sure

that the patient is in the reverse Trendelenburg position to minimize the risk of an air embolism.

(1) Choose right or left groin area for insertion.

(2) Prepare groin and abdomen on same side.

c. Make incision 1 cm long: 1 cm caudad and 1 cm

lateral to pubic tubercle (Fig. 32.12).

d. Spread incision into subcutaneous tissues, using

curved mosquito hemostat.

(1) Incise superficial fascia.

(2) Identify saphenous vein lying medial and inferior to its junction with femoral vein at foramen

ovale (Fig. 32.12).

e. Move 0.5 to 1 cm distally before

(1) Passing curved mosquito hemostat behind vein.

This avoids inadvertent damage to femoral vein.

(2) Placing two 4-0 absorbable suture ligatures

loosely around vein

f. Create a tunnel, using a small hemostat or tunneling instrument, in subcutaneous plane laterally

onto abdomen, just above or lateral to umbilicus or

on lateral thigh.

g. Flush catheter with heparinized saline and replace

cap.

h. Pull catheter through tunnel into groin wound so

that the Dacron cuff is just within the skin incision.

Estimate the length of the catheter to be inserted so

that the tip will be in inferior vena cava at junction

with right atrium.

i. Cut catheter to appropriate length, and bevel intravascular end (optional).

j. Dissect saphenous vein to junction with common

femoral vein.

Visualizing the junction prevents inadvertent

direction of catheter into lower extremity.

k. Apply traction to vein, using caudad suture. Lateral

tension may also be applied by a scrubbed assistant,

using fine nontoothed vascular forceps.

l. Make transverse venotomy.

m.Dilate vein, if necessary, with blunt dilatator.

n. Moisten catheter with saline to ease passage into

vein.

o. Maintain back-traction on caudad suture to control

bleeding.

A

B

Fig. 32.9. Formation of a subcutaneous tunnel with a VimSilverman needle. A: Tunnel on the anterior chest wall.

B: Alternative route under the scalp.

Fig. 32.10. Broviac catheter with transparent dressing.

 

Chapter 32 ■ Central Venous Catheterization 203

15. Two small, curved mosquito hemostats

16. Dissecting scissors

17. 4-0 Vicryl suture on small, curved needle; 6-0 polypropylene on a tapered needle. This is used for a pursestring stitch as an alternative to ligation of the vessels.

18. Needle holder

19. Suture scissors

20. Appropriate materials for occlusive dressing of choice

Nonsterile

1. Cap and mask

2. Roll of 4- × 4-inch gauze

3. Tape measure

4. Adhesive tape

D. Techniques

In the neonate, the cervical veins are preferable to the

lower-extremity veins. The cervical veins are easily accessible and are a proportionately larger size. When the lower

extremities are used, the greater saphenous vein is often

selected in pediatric patients because of its large size and

consistent anatomy. It is not established whether femoral or

jugular sites have fewer complications in neonates (16,17).

1. Catheter placement via jugular veins

a. Immobilize infant in position similar to that for percutaneous insertion of subclavian venous catheter.

Make sure that the patient is in the Trendelenburg

position to minimize the risk of an air embolism.

b. If right side is to be catheterized, turn head to left

and extend neck. Care must be taken not to extend

the head too much, as this may result in occlusion

of the vein.

c. Estimate length of catheter to be inserted by measuring from a point midway between the nipple and

the midpoint of the clavicle to a point over the sternocleidomastoid muscle at the junction of the middle and lower third of the neck (Fig. 32.7).

d. Put on cap and mask.

e. Scrub as for major procedure and put on gown and

gloves.

f. Prepare neck and scalp area or right chest wall with

antiseptic solution such as iodophor and drape out

the sterile field.

g. Make small, transverse incision (1 to 2 cm) through

skin and platysma muscle low in the neck for the

external jugular and higher up for the facial vein.

h. Free external jugular or facial vein by blunt dissection with curved mosquito hemostat. If internal jugular vein is used, sternocleidomastoid muscle must

be split to locate vein.

i. Pass curved mosquito hemostat behind the vein,

and place proximal and distal ligatures of 4-0 absorbable suture loosely around vein (Fig. 32.8). Be careful not to twist the vessels as the suture is advanced.

j. Using a blunt tunneler, create a subcutaneous tract

from neck to exit on the chest wall medial to the

right nipple. In a baby girl, make sure that the tunnel is far from the breast bud (Figs. 32.9 and 32.10).

k. Thread the end of the catheter through the opening

in the tunneler, and guide the catheter gently

through the subcutaneous tract.

l. Fill the catheter system with heparinized flush

solution.

Fig. 32.7. The jugular veins in relation to major anatomic landmarks.

Fig. 32.8. Catheterization of the external jugular vein; venotomy has been performed prior to inserting the catheter.

 

Infection rates, catheter dwell times, patient outcomes,

and rates of complications should be monitored (2).

10. Remove catheter as soon as it is no longer medically

necessary by slowly withdrawing it from insertion site.

Clean insertion site with prep prior to withdrawing

catheter. Hold pressure over site if bleeding is a problem. Remove prep from skin. Place a clean gauze dressing over site. Document length removed.

Placement of Central Venous Catheters

by Surgical Cutdown

A. Types of Catheters

Silicone catheters are preferred because they are constructed of relatively inert materials, offer increased pliability, and are associated with lower rates of infection and

thrombosis. These catheters are placed in a central vein,

and the distal end is tunneled subcutaneously a short distance from the access site to an exit wound. The catheters

usually have a single lumen with a Dacron cuff, which

adheres to the subcutaneous tract, anchoring the catheter.

Polyethylene catheters have a higher rate of infection and

thrombolytic complications and are not recommended for

long-term IV access.

B. Contraindications

In addition to the relative contraindications delineated earlier, the internal jugular vein should be avoided if the contralateral jugular vein has been catheterized previously, or if

there is thrombosis of the jugular venous system on the

opposite side.

C. Equipment

Sterile

1. Skin prep: Per institutional policy (e.g., 10% povidone–

iodine, or 0.5% chlorhexidine solution)

2. Gown and gloves

3. Cup with antiseptic solution

4. Sterile transparent aperture drape; four sterile towels to

ensure a sterile operative field

5. Four 4- × 4-inch gauze squares

6. Local anesthetic: 0.5% lidocaine HCl in labeled 3-mL

syringe with 25-gauge venipuncture needle

Consider sedation and pain medication in addition

to local anesthesia. Patients who are intubated may be

given a sedative and muscle relaxant in addition to

local anesthesia. When patients are taken to the operating room, general anesthesia is preferred.

7. Catheter of choice

8. Heparinized 0.25 N saline flush solution (1 U/mL) in

3-mL syringe

9. 4-0 polyglactin suture (Vicryl; Ethicon, Somerville,

New Jersey) and 5-0 nylon suture (black monofilament

nylon) on cutting needles (see Appendix B)

10. T connector connected with a sterile 3-mL syringe

filled with heparinized saline

11. No. 11 scalpel blade and holder

12. Two small tissue retractors or self-retaining retractor

13. Tissue forceps

14. Fine vascular forceps

 

202 Section V ■ Vascular Access

4. If the catheter is too far in, as confirmed by radiography

or echocardiography, it may be pulled back, prior to

replacing dressing. Do not advance the catheter, as the

risk of contamination is high.

5. Use sterile technique for dressing changes (mask, cap,

and sterile gloves; sterile gown is optional).

6. Prepare sterile field: Place drape under extremity.

Utilizing the prep solution, prepare the skin at and

around the insertion site, working outward in concentric circles. Allow the prep solution to dry. Repeat process with new gauze/prep solution. Drape prepared

area, leaving insertion site exposed.

7. Follow steps D1 through D7 to complete the PICC

dressing change.

F. PICC Care and Maintenance

1. Evaluate appearance of the catheter and the tissue

around the insertion site frequently.

2. Change IV tubing according to unit policy. Utilize

aseptic technique when changing tubing.

3. To prevent contamination of the line, enter the PICC

only when absolutely necessary.

a. Avoid the use of stopcocks in the line.

b. Always “scrub the hub” with alcohol pad (or similar

product) prior to breaking a connection.

c. If the catheter must be used to infuse medications,

arrange the intermittent injection tubing so that it

does not come in contact with the parenteral alimentation solution until the terminal infusion site.

A dedicated “closed” medication administration system is recommended (13). Gently flush tubing prior

to and after medication administration. Ensure that

the flush and medication is compatible with the parenteral alimentation.

4. Prime volumes are usually <0.5 mL. Use a 5- to 10-mL

syringe when needed to check catheter patency. Do not

use force if resistance is encountered. A small-barreled

syringe (such as a 1-mL syringe) may generate too

much pressure, resulting in catheter rupture (12).

5. Administer a constant infusion of IV fluids at a rate of at

least 1 mL/h. Follow the manufacturer’s recommendations for maximum flow rates.

6. The addition of heparin in small doses (0.5 units heparin/kg/h or 0.5 units heparin/mL of IV fluids) reduces

the risk of occlusion and prolongs catheter patency

(14).

7. Do not utilize the PICC for routine blood sampling.

8. Packed red blood cell transfusions should be given

through a PICC only if absolutely necessary. Although

there is no clinically significant hemolysis, there is a

potential for occlusion of the catheter (15).

9. Monitor quality indicators to identify and solve problems.

 

San Antonio, TX: Klein Baker Medical, 1998, with permission.)

Table 32.4 Examination of the Catheter Site

Assessment Comments

Catheter:

Note external catheter length

Catheter length should be clearly documented. If external length has changed, get radiograph(s) to assess where the

catheter tip is located.

If the catheter is pulled out, cover site with occlusive dressing and measure catheter length to assure that some of the

catheter was not retained in the vessel.

Assess for kinks, tension, damage Kinks and tension can damage catheter. It is recommended that damaged catheters be removed, but some manufacturers provide repair kits.

Insertion site/surrounding skin:

Erythema, drainage, bleeding, edema,

phlebitis, skin breakdown

Mild erythema and/or phlebitis is common after the catheter is inserted. If condition is severe and/or is persistent,

consider removing catheter.

Mild oozing of blood should not persist longer than 24 h.

Edema may be due to venous stasis from lack of extremity movement, constrictive dressings, thrombus, damage to

internal structures, localized infection, or infiltration of infusion into soft tissue.

Avoid skin breakdown by utilizing skin barriers underneath hub, removing dressing adhesives with care, minimizing

tape, and removing antiseptics from skin before applying dressing.

Drainage/leaking Purulent drainage may be due an infectious process. Consider obtaining blood cultures and/or removing the catheter.

Clear drainage may be indicative of infusion leakage. This may be due to catheter occlusion, infiltration, or damage

to catheter.

 

Chapter 32 ■ Central Venous Catheterization 201

2. To prevent migration of the catheter, secure it to the

skin a few millimeters from the insertion site with a

small piece of sterile tape (avoid using tape that contains wire).

3. If the catheter has not been trimmed, loosely coil the excess

length of catheter close to the insertion site and secure to

the skin with more sterile tape. Ensure that there is no

kinking or stretching of the catheter under the dressing.

4. Apply a semipermeable transparent dressing over the

area surrounding the insertion site.

5. Do not allow tapes or transparent dressing to extend

around the extremity. The dressing will form a constricting tourniquet as the infant grows or if there is

venous congestion.

6. Place tape under the catheter hub and criss-cross it over

the hub (chevron). Do not obscure visualization of the

insertion site (Fig. 32.6).

7. To prevent skin breakdown, a skin barrier of hydrocolloid

material or soft gauze can be placed under the hub.

E. Dressing Changes

1. Mild oozing of blood from the insertion site may occur

for up to 24 hours. If oozing occurs, the initial dressing

should be changed when it subsides. If oozing of blood

is a problem, a small piece of thrombin foam can be

applied over the insertion site and under the dressing

for the first 24 hours after insertion.

2. The catheter site dressing should be replaced when it

becomes damp, soiled, or loose. Transparent dressings

should be changed every 7 days except in those patients

in whom the risk of dislodging the catheter outweighs

the benefit of changing the dressing (2).

3. Inspect catheter site carefully at each dressing change

(Table 32.4).

o. Secure catheter at skin insertion site with a small

piece of sterile tape strip (avoid using tape that

contains wire) and cover with sterile gauze until

radiographic confirmation of position.

D. PICC Dressings (Figs. 32.5, 32.6)

1. Antimicrobial prep solutions should be removed from

the skin with sterile water or saline and allowed to dry

before dressing is placed. Do not use topical antibiotic

ointments or creams on insertion sites (2).

Fig.32.6. PICC dressing with trimmed catheter. No excess

catheter is present externally. The silicone heart is anchored with

a piece of tape, and a sterile transparent dressing is placed over the

insertion site. With use of a “chevron” technique, another piece of

tape is placed under the catheter extension, next to the silicone

heart, and crossed over on top of the transparent dressing. (From

Klein C. NeoPicc: The Neonatal and Pediatric Workshop Manual.

 

Caution: When using a break-away needle, never

advance the needle or retract the catheter after

inserting it into the needle; the catheter may be severed by this action.

f. With small, gentle nudges, a few millimeters at a

time, advance the catheter through the introducer

to a distance of about 6 to 7 cm into the vein.

g. Once the catheter is successfully advanced to about

6 or 7 cm, withdraw the introducer carefully (an

alternative is to insert the catheter to the predetermined distance before withdrawing the introducer).

h. To withdraw the introducer, stabilize the catheter by

applying gentle pressure over the vein proximal to

the introducer, and then remove it carefully from

the insertion site. Break or peel away the introducer

by splitting the wings, and then carefully peel it

away from the catheter.

i. Continue to advance the catheter into the vein to

the premeasured length, by nudging it farther, a few

millimeters at a time, using the fine forceps.

j. Difficulties in advancing catheter: Gently massage

the vein in the direction of blood flow, proximal to

the insertion site, or gently flush the catheter intermittently with 0.5 to 1 mL of heparinized saline;

repositioning the extremity or the head may help.

k. Aspirate to visualize blood return in the catheter,

and flush with 0.5 to 1 mL of heparinized saline to

clear the catheter.

l. Verify length of catheter inserted and adjust as necessary.

m.Attach sterile extension set as per unit protocol.

n. Apply gentle pressure on insertion site with gauze

pad to stop any bleeding.

Table 32.3 Patient Position and Measurement for PICC Insertion

Site of Insertion Position of Baby Measurement

Antecubital veins Supine, abduct arm 90 degrees from trunk; turn head toward

insertion site to prevent catheter from traveling cephalad

through ipsilateral jugular vein

From planned insertion site, along venous pathway,

to suprasternal notch, to third RICS

Saphenous or popliteal veins Supine for greater saphenous vein, prone for small saphenous or

popliteal; extend leg

From planned insertion site, along venous pathway,

to xiphoid process

Scalp veins Supine, turn head to side; may have to turn head to midline during procedure to assist advancement of catheter

Follow approximate venous pathway from planned

insertion site near ear, to jugular vein, right SC

joint, to third RICS

External jugular vein Supine, turn head to side; place roll under neck to cause mild

hyperextension

From planned insertion site, to right SC joint, to

third RICS

Axillary vein Supine, externally rotate and abduct arm 120 degrees, flex forearm and place baby’s hand behind head; vein is found above

artery between medial side of humeral head and small tuberosity of the humerus

From planned insertion site, to right SC joint, to

third RICS

PICC, peripherally inserted central catheter; RICS, right intercostal space; SC, sternoclavicular.

200 Section V ■ Vascular Access

A B

C D

E F

Fig. 32.5. A: Venipuncture with peel-away cannula introducer. B: Withdraw the introducer needle

from the sheath. Note that the introducer sheath is supported to avoid displacement. C: Insert the catheter

into the introducer sheath using fine nontoothed forceps. D: Withdraw the introducer sheath. E: Remove

the introducer sheath by splitting and peeling it away from the catheter. F: Transparent dressing on PICC

catheter. Note that the excess catheter length has been coiled in place under the dressing.