what is the limit of osmolarity for tpn
DESCRIPTION
TPN THROUGH PERIPHERAL AND CENTRAL LINETRANSCRIPT
What is the limit of osmolarity for parenteral nutrition formulas used in
peripheral line administration?
Concerns about the osmolarity of peripheral parenteral nutrition (PPN) formulas
thrombophlebitis
incidence of thrombophlebitis is estimated ato range from a low of
2.3% to as high as
70%.
The range is this wide as there are many variables to consider
osmolarity PPN additives such as heparin and
lipids duration of PPN administration the types of catheters and needles
used
So, although the etiology of
thrombophlebitis in PPN is often multifactorial, the osmolarity of the infused PPN solution may be an important variable.
To decrease the likelihood of phlebitis, the osmolarity of PPN
should be between 600 and
900 mOsm.
For solutions with an osmolarity of
1100 mOsm or greater, lipid emulsion may be added to increase the patient's tolerance for the infusion. However, this approach is not recommended for patients with contraindications,
such as
high triglycerides.
Alternatively
hydrocortisone and heparin can be added to hyperosmolar solutions of up to
1200 mOsm to prevent phlebitis.
Addition of heparin to PN solutions “reduces the formation of a fibrin sheath around the catheter, may
reduce phlebitis… and increases the duration of catheter patency” (Groh-Wargo, et al., 2000). Heparin also
stimulates the release of lipoprotein lipase, which may improve lipid clearance.
This approach may not be appropriate for all types of patients. For example, heparin should be avoided in patients with a history of heparin-induced thrombocytopenia. In addition, hydrocortisone and heparin may not be stable additives for all PPN solutions, especially those containing fat emulsion.
calculating the osmolarity of PPN solutions
Osmolarity (mOsm/L) = (grams dextrose / liter) x 5] + [grams amino acid / liter) x 10] + [(mEq cations / liter) x 2]
Another way
Osmolarity (mOsm/L) =(Amino acid×8)+(glucose ×7)+(Na×2)+(phosphorus×0.2)- 50
Because of the limitations in osmolarity of PPN solutions, the typical PPN composition provides a final concentration of amino acids that is
generally between 2.5% (25 g/L)
and 5% (50 g/L). Dextrose concentrations
NaCL0.9%
LR NaCL3%
ALBUM5%
NaHCO3 D10%
D5 1/2NS
D5NS
KCL
Na(mEq/L)
154 130 513 130-160
4.2?%(.5mEq/ml)8.4%(1mEq/ml)
154
CL(mEq/L)
154 109 513 130-160
0 154
K(mEq/L)
0 4 0 0 0 0 1ml=2mEq
Osmolarity(mOsm/L)
308 275 1025 310 8.4%(2000)
505 406 560 4000
Lactate(mEq/L)
0 28 0 0 0 0 0 0
Dextrosegm/L
0 0 0 0 0 100 50 50
TPN SOLUTIONSAMINOSIN 15% amino acid 1300
TRAVASOL 10% amino acid 998
LIPID 10% 276
LIPID 20% 258
NOVAMINE15% amino acid 1388
HEPTAMINE 8 % amino acid 785