Vascular Access The Alpha and Omega of CRRT Rick Hackbarth MD Division of Pediatric Critical Care Grand Rapids, Michigan.

Vascular AccessThe Alpha and Omega of CRRT

Rick Hackbarth MD

Division of Pediatric Critical Care

Grand Rapids, Michigan

Vascular Access Wisdom

“If you don’t have good access you might as well go home!”

Vascular Access

The portal from patient to circuit Affects circuit life

Lost circuits may expose patients to more transfusions and frustrates staff

Affects clearance Lower blood flow rates and hemofiltration rates More downtime

Vascular Access

Two questions to be answered-

What size catheter to use?

Where to put it?

Vascular Access Wisdom

“Size matters!”

Vascular Access

Pousielle’s Law-

Smaller diameters offer greater resistance to flow Longer lengths offer greater resistance to flow Decreasing the diameter by 1/5th is the same as doubling the

length (roughly a 2 French size difference)

Q = ∆Pπr4

8l

Vascular Access

ppCRRT Registry Access Study

13 Pediatric Institutions 376 patients 1574 circuits Circuit survival by Catheter size, site, and modality

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access

Figure 2: Mean Patient Weight vs Catheter Size

0

20

40

60

80

100

5 French 7 French 8 French 9 French 10 French 11.5French

12.5French

Catheter Size

Kg

Hackbarth R et al: IJAIO 30:1116-21, 2007

Number of Patients% Survival at 60

hours

Catheter Size*5 6 0 (p <0.0000)7 57 43 (p < 0.002)8 65 55 (NS)9 35 51 (p < 0.002)

10 46 53 (NS)11.5 71 57 (NS)12.5 64 60 (NS)

Insertion Site

Internal Jugular 58 60 (p < 0.05)Subclavian 31 51 (NS)

Femoral 260 52 (NS)

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access

Hackbarth R et al: IJAIO 30:1116-21, 2007

Shorter life span for 7 and 9 Frenchcatheters (p< 0.002)

1st 72 hrs of circuitlife only

Figure 1: Catheter Location by Size

0

10

20

30

40

50

60

70

80

90

100

5 French 7 French 8 French 9 French 10 French 11.5 French 12.5 French

Catheter Size

%

Femoral

IJ

Subclavian

Unknown

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access Wisdom

“Location, location, location!”

Vascular Access

“Location, location, location!”

Options: Femoral vein Subclavian vein Internal Jugular vein

Vascular Access

“Location, location, location!”Femoral VeinPros: Accessible under almost any conditions Easier to maintain hemostasisCons: Potential for kinking More recirculation Thrombosis Problematic flow with increased abdominal pressures

Vascular Access

“Location, location, location!”Subclavian VeinPros: Shorter catheter/better flow Less recirculationCons: Potential for kinking Difficult hemostasis Potential for venous narrowing Less accessible with cervical trauma

Vascular Access

“Location, location, location!”Internal Jugular VeinPros: Shorter catheter/better flow Less recirculationCons: Difficult hemostasis Less accessible with cervical trauma Catheter length problematic in small infants

Vascular Access

Highly variable position of the IJ vein Ultrasound can be quite helpful

Maecken T et al: CCM 35: S178-85, 2007

Number of Patients% Survival at 60

hours

Catheter Size*5 6 0 (p <0.0000)7 57 43 (p < 0.002)8 65 55 (NS)9 35 51 (p < 0.002)

10 46 53 (NS)11.5 71 57 (NS)12.5 64 60 (NS)

Insertion Site

Internal Jugular 58 60 (p < 0.05)Subclavian 31 51 (NS)

Femoral 260 52 (NS)

Hackbarth R et al: IJAIO 30:1116-21, 2007

Vascular Access

Hackbarth R et al: IJAIO 30:1116-21, 2007

Survival favors IJLocation (p< 0.05)

Vascular Access Wisdom

“It’s déjà vu all over again.”

Vascular Access

Recirculation

More of an issue in femoral catheters especially shorter than 20 cm

Is this really a practical concern with 24/7 clearance? Catheter proximity may be a bigger issue

Vascular Access

Note the relationship of the line tips.

Vascular Access

Catheter proximity

Inadvertent removal of infusions Circuit clotting with platelet transfusions Entraining calcium into the circuit

Vascular Access Wisdom

“You can’t always get what you want, but you might get what you need!”

Vascular Access

French

Size5 7 8 10 12

Flow Rate

(ml/min)? 80-100 150-200 250-300 285-330

Catheter Specifications

Vascular Access

French

Size5 7 8 10 12

Diameter

(mm)1.67 2.3 2.7 3.3 4.0

Catheter Specifications

Vascular Access

Vessel diameter vs Age

0

0.5

1

1.5

2

2.5

3

0 2 4 6 8 10 13 16 19

Years

cmFemoral

IVC

IJ

Steinberg et al: Catheterization and Cardiovascular Diagnosis 27: 197-201, 1992

Vascular Access

Pousielle’s Law-Q = ∆Pπr4

8l

Vascular Access

Relative Resistance to IVC Blood Flow

0

2

4

6

5 7 8 10 12

Catheter Size (French)

Rela

tive R

esis

tan

ce

Infant

2 year old

6 year old

10 year old

16 year old

Vascular Access

Relative Resistance to IVC Blood Flow

0

2

4

6

5 7 8 10 12

Catheter Size (French)

Rela

tive R

esis

tan

ce

4kg

12 kg

20 kg

30 kg

60 kg

Vascular Access

It was six men of Indostan

To learning much inclined,

Who went to see the Elephant

(Though all of them were blind),

That each by observation

Might satisfy his mind.

John Godfrey Saxe

The Blind Men and the Elephant

Differing Perspectives on the ICU Patient

Vascular Access

And so these men of Indostan

Disputed loud and long,

Each in his own opinion

Exceeding stiff and strong,

Though each was partly in the right,

And all were in the wrong!

John Godfrey Saxe

The Blind Men and the Elephant

Differing Perspectives on the ICU Patient

Vascular Access

Vascular Access

Vascular Access

Vascular Access

Vascular Access

Two questions to be answered-

What size catheter to use?

Where to put it?

Vascular Access

What size catheter should we use?

Don’t use a 5 French catheter. Choose the largest diameter that is safe for the child. Choose the smallest catheter that will achieve the

necessary flow easily. Choose the the minimum length to position the tip for

optimal flow. In the femoral position, longer catheters will minimize

recirculation

Vascular Access

Where should the catheter go?

What sites are available? Are there anatomic or physiologic constraints? Which vessel is optimal for the catheter size? Is the patient coagulopathic? Consider patient mobility and risk of kinking. Is there elevated intra-abdominal pressure?

Vascular Access

Where should the catheter go?

Answer: Internal Jugular vein if possible

PATIENT SIZE CATHETER SIZE &

SOURCE

SITE OF INSERTION

NEONATE Single-lumen 5 Fr (COOK) Femoral artery or vein

Dual-Lumen 7.0 French

(COOK/MEDCOMP)

Femoral vein

3-6 KG Dual-Lumen 7.0 French

(COOK/MEDCOMP)

Internal/External-Jugular,

Subclavian or Femoral vein

Triple-Lumen 7.0 Fr

(MEDCOMP)

Internal/External-Jugular,

Subclavian or Femoral vein

6-30 KG Dual-Lumen 8.0 French

(KENDALL/ARROW)

Internal/External-Jugular,

Subclavian or Femoral vein

>15-KG Dual-Lumen 9.0 French

(MEDCOMP)

Internal/External-Jugular,

Subclavian or Femoral vein

>30 KG Dual-Lumen 10.0 French

(KENDALL, ARROW)

Internal/External-Jugular,

Subclavian or Femoral vein

>30 KG Triple-Lumen 12 French

(KENDALL/ ARROW)

Internal/External-Jugular,

Subclavian or Femoral vein

Disney Wisdom

“I would rather entertain and hope that people learned something than educate people and hope they were entertained.”