Preparation
of 0.1 N solution
[100 ml (100 meq ) of 1.0N HCL] [1000 ml]
[Infusion rate: see bottom section]
Filter HCL with 0.22 micron filter before adding
it to the IV bag .
Alternatively
(Using
37% HCL stock bottle):
[8.3 ml of 37% HCL] [1000 ml NS or D5W]
Preparation of 0.15 N
solution
[150 ml (150 meq) of 1.0 N HCL] [1000 ml]
-This
agent must be infused in glass or
polyolefin container.
-Hydrochloric
acid solution should be administered
through a central venous line to prevent
vein irritation, thrombophlebitis, or
tissue necrosis. Do NOT infuse via a
peripheral vein! Injection of HCl
into a peripheral vein may cause
extravasation and can produce severe
tissue necrosis.
-Solutions
for infusion should NOT exceed 0.2 N
(increased risk of hemolysis and
increased venous irritation).
Concentrations >0.1 N have been
reported to cause corrosive effects,
even when administered through a central
venous catheter.
-Serum
electrolytes and blood gases should be
measured every 4 hours.
-Solution
should be filtered with a teflon 0.22
micron filter before adding to an IV
bag. Sample filter: GE PTFE (Teflon®)
Syringe Filters: Membrane compatible
with most aggressive solutions. http://www.osmolabstore.com/OsmoLabPage.dll?BuildPage&1&1&1051 |
Dosing:
H+ ion deficit (mEq) = 0.3 X weight (kg) X
(measured HCO3 - desired HCO3 [mEq/L])
Rate of H+ replacement: 0.1 - 0.2 mEq/kg/hour
For example, 0.1 N solution IV at 100 mL/h
provides about 10 mEq/h
Stock bottle of
37% HCL.
Determination of molarity of 37% HCL V/V
37 ml of solute/100 ml of solution.
HCL - 37% v/v. Specific gravity: 1.19 g/ml
37ml/100 ml or 370 ml/1000 ml x 1.19 g/ml = 440.3
g/L
HCL Molecular weight = 36.5
Molarity:
440.3 grams /36.5 grams = 12.06 M or ~12M
====================
Compounding 1 liter of 0.1N Solution
====================
M1V1 = M2V2
(0.1)(1000) = (12) (x)
x = (0.1) (1000) / 12
x = 8.3 ml
Therefore add 8.3
ml of 37% HCL to 1 liter of D5W or NS to create a
0.1N HCL solution.
---OR ---(Alternative calculation)
12M (37% HCL) = 12 moles/L = 12 x 36.5 = 438 g/L =
438 mg/ml.
Need 0.1 N = 0.1 M
0.1 M x 36.5 = 3.65 g/L = 3650 mg.
3650 mg / 438 mg = 8.33 ml*
|
| Stability/storage:
24 hr (RT)
Indication:
treatment of severe or refractory metabolic
alkalosis. IV HCl may be indicated in severe
metabolic alkalosis (pH >7.55) or when NaCl or
KCl cannot be administered because of volume
overload or advanced renal failure. May also be
indicated if rapid correction of severe metabolic
alkalosis is warranted (eg, cardiac arrhythmia or
hepatic encephalopathy.)
Equations:
Base
excess in blood (BE-B)
Base excess in blood (BE-B) is the number
of mmol of strong acid that is needed to
adjust to pH 7.4 a blood sample tested at
pCO2 of 40 mm Hg and 37 C.It indicates the
deviation in mmol/l of the buffer bases
from the normal value.
BE - B = (1 - 0.014[Hb])([HCO3-] - 24 +
(1.43[Hb] + 7.7)(pH - 7.4))
The BE requires the measurement of blood
pH, hemoglobin, and HCO3. |
| H+
deficit (mEq) = 0.3 x Wt(kg) x
([HCO3-] - 35) |
| Rate
of H+ replacement =0.1 to 0.2
meq/kg per hour. |
Definitions:
The 'Normality' of a solution is the 'Molarity'
multiplied by the number of equivalents per mole.
The 'Molarity' of a solution is the number
of moles of solute in one liter of solution.
Source: http://www.uab.edu/clabsc/solution.htm
Source:
DRUGDEX®:
Storage and Stability:
HYDROCHLORIC ACID (0.1N) is stable and
compatible in VIAFLEX(R) PLASTIC
CONTAINERS over a 24 hour storage period (Pers
Comm, 1987).
Most studies recommend a 0.1 to 0.15
Normal hydrochloric acid solution prepared
in sterile water, 5% dextrose in water or
normal saline (Wagner et al, 1980g;
Williams & Lyons, 1980g). One group of
clinicians prepared a 0.1 Normal
hydrochloric acid solution by drawing 100
milliequivalents of concentrated
hydrochloric acid into a syringe and
filtering it through a disposable 0.22
micron filter as it was added to a liter
of 5% dextrose in water or normal saline
(Wagner et al, 1980g). Others prepared a
0.15 Normal hydrochloric acid solution by
diluting 12.5 milliliters of concentrated
hydrochloric acid (35% to 38%) to a total
volume of 1 liter with sterile water
(Williams & Lyons, 1980g).
INTRAVENOUS RATE OF ADMINISTRATION:
The rate of infusion was 100 to 125
milliliters/hour of a 0.15 Normal
hydrochloric acid solution in sterile
water (Williams & Lyons, 1980g). One
group of practitioners infuses a liter of
0.1 Normal hydrochloric acid in 5%
dextrose and water or normal saline over 4
to 6 hours (Wagner et al, 1980g). Some
clinicians have corrected severe metabolic
alkalosis with prolonged infusion of
hydrochloric acid (over a period of 17
days), administering 100 to 400
milliequivalents hydrochloric acid daily
through a central venous catheter as 0.1
Normal hydrochloric acid (Reisman &
Puri, 1982f).
The amount of hydrochloric acid (HCL)
administered is based upon base excess (milliequivalent/liter),
with an equivalent amount being
administered. One report recommends the
following formula (Wagner et al, 1980g):
HCL (mEq) = Weight (kilogram) x 0.3
X base excess (mEq/liter).
The amount of hydrochloric acid
administered to each of the 21 patients
treated was based upon 1 of 3 equations:
Bicarbonate Excess = (0.5 X Weight in kg)
X (serum bicarbonate -24); OR Chloride
Deficit = (0.2 X Weight in kg) X (103-
serum chloride); OR Base Excess = (0.3 X
Weight in kg) X (measured base excess).
The pH of amino acid solutions containing
added hydrochloric acid was significantly
higher than that observed with
hydrochloric acid added to normal saline.
The addition of 100 milliequivalent/liter
hydrochloric acid to normal saline
produced a pH of approximately 1.5,
whereas, addition of the same amount to a
3.5%, 5.5%, and 8.5% amino acid solution
increased the pH to approximately 3, 4.5,
and 5, respectively.
The
infusion generally continues until the
total base excess is between 0 and 50
milliequivalent (Williams & Lyons,
1980g).
|
Source:
UpToDate®:
Hydrochloric acid — If acetazolamide is
ineffective, the metabolic alkalosis can
be corrected directly by the intravenous
infusion of HCl, which buffers the excess
bicarbonate. HCl is usually given as an
isotonic solution (150 meq per liter) over
8 to 24 h. It can be infused into a major
vein (since HCl is very corrosive) or into
a peripheral vein if the HCl is buffered
in an amino acid solution and given with a
fat emulsion.
The amount of HCl required (in meq) can be
estimated from the space of distribution
of bicarbonate in metabolic alkalosis
(approximately equal to 50 percent of lean
body weight [LBW] in kg) times the
bicarbonate excess per liter:
HCO3 excess = 0.5 x LBW x (Plasma HCO3 -
24)
In a 60 kg woman with a plasma bicarbonate
concentration of 38 meq/L, for example:
HCO3 excess = 0.5 x 60 x 14 = 420 meq
It is important to remember that this
formula is only an estimate and that it
does not take into account any continuing
acid loss, as with nasogastric suction.
Minimizing continuing acid loss in this
setting with an H2-blocker also may be
helpful. |
Source:
Merck Manual:
http://www.merck.com/mmpe/sec12/ch157/ch157d.html
Metabolic
Alkalosis:
Underlying conditions are treated, with
particular attention paid to correction of
hypovolemia and hypokalemia.
Patients with Cl-responsive metabolic
alkalosis are given 0.9% saline solution
IV; infusion rate is typically 50 to 100
mL/h greater than urinary and other
sensible and insensible fluid losses until
urinary Cl rises to > 25 mEq/L and
urinary pH normalizes after an initial
rise from bicarbonaturia. Patients with Cl-unresponsive
metabolic alkalosis rarely benefit from
rehydration.
Patients with severe metabolic alkalosis (eg,
pH > 7.6) sometimes require more urgent
correction of serum pH. Hemofiltration or
hemodialysis is an option, particularly if
volume overload is present. Acetazolamide
250 to 375 mg po or IV once/day or bid
increases HCO3 − excretion but may
also accelerate urinary losses of K+ and
PO4 −; volume-overloaded patients
with diuretic-induced metabolic alkalosis
and those with posthypercapnic metabolic
alkalosis may especially benefit.
Hydrochloric acid in a 0.1 to 0.2
normal solution IV is safe and effective
but must be given through a central
catheter because it is hyperosmotic and
scleroses peripheral veins. Dose is 0.1 to
0.2 mmol/kg/h, with frequent monitoring of
ABG and electrolytes.
|
| Alternatives
(usage depends on patient specific
conditions): |
-
Ammonium chloride (NH4Cl) (Note:
Hydrochloric acid is the drug of choice in
patients with hepatic dysfunction who are
unable to tolerate ammonium chloride.)
CLINICAL PHARMACOLOGY:
The ammonium ion (NH4+) in the body plays
an important role in the maintenance of
acid-base balance. The kidney uses
ammonium (NH4+) in place of sodium (Na+)
to combine with fixed anions in
maintaining acid-base balance, especially
as a homeostatic compensatory mechanism in
metabolic acidosis. When a loss of
hydrogen ions (H+) occurs and serum
chloride (Cl−) decreases, sodium is
made available for combination with
bicarbonate (HCO3−). This creates an
excess of sodium bicarbonate (NaHCO3)
which leads to a rise in blood pH and a
state of metabolic alkalosis.
The therapeutic effects of ammonium
chloride depend upon the ability of the
kidney to utilize ammonia in the excretion
of an excess of fixed anions and the
conversion of ammonia to urea by the
liver, thereby liberating hydrogen (H+)
and chloride (Cl−) ions into the
extracellular fluid.
Dosing: Ammonium Chloride
Injection, USP is administered
intravenously and must be diluted before
use. Solutions for intravenous infusion
should not exceed a concentration of 1% to
2% of ammonium chloride. Dosage is
dependent upon the condition and tolerance
of the patient. It is recommended that the
contents of one to two vials (100 to 200
mEq) be added to 500 or 1000 mL of
isotonic (0.9%) sodium chloride injection.
The rate of intravenous infusion should
not exceed 5 mL per minute in adults
(approximately 3 hours for infusion of
1000 mL). Dosage should be monitored by
repeated serum bicarbonate determinations.
Supplied:
100 mEq (5 mEq/mL) - 20 ml vial
267.5 mg/ml.
For the treatment of hypochloremia or
hypochloremic metabolic alkalosis in
patients who cannot receive sodium
chloride and who do not have end-stage
hepatic disease: Intravenous
dosage: Adults: Individualize dosage
based on the patient's carbon dioxide
combining power. Each gram of ammonium
chloride will reduce the carbon dioxide
combining power of a 70-kg adult by about
1.1 volume %, or 16 mg/kg will lower the
carbon dioxide combining power by 1 volume
%. In the absence of edema or hyponatremia,
the dosage may be calculated on the basis
of the chloride deficit by the following
formula: mEq of chloride ion (as ammonium
chloride) = chloride deficit x 0.2 L/kg x
weight (kg). The chloride deficit is 103
— serum Cl in mEq/L. One-half of the
calculated value should be administered,
the carbon dioxide combining power should
be rechecked and the need for further
treatment assessed. Do not exceed a
concentration of 1—2% of ammonium
chloride or an infusion rate greater than
5 ml/minute. |
|
- Acetazolamide
(Diamox): chloride-resistant metabolic
alkalosis. Metabolic alkalosis
(unlabeled use): I.V. 250 mg every 6 hours
for 4 doses or 500 mg single dose;
reassess need based upon acid-base status.
Alternatively: 5-10 mg/kg/d PO/IV divided
q6h. Carbonic anhydrase inhibitor that
blocks HCO3 reabsorption in the proximal
renal tubules.
|
|
