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PDAT3 > 1 - Acid Base Disorders > Flashcards

1 - Acid Base Disorders Flashcards

1
Q

Type of Disorder resulting from altercations in

CARBON DIOXIDE
CO2
(HCO3- = Base)

A

Resiratory Disorder

Lungs

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2
Q

Metabolic Base

states where…

A
  • *Excess Acid Produced**
  • –> buffering-associated decrease in HCO3-*

Kidneys are unable to retain HCO-3
or there is a GI Loss –> loss in plasma buffering capacity

  • *Renal Hydrogen Ion secretion is decreased**
  • -> decreased reabsorption of HCO3- = renal induced acidosis
  • Loss of Anions*
  • -> cause kidneys to generate/retain HCO3- to maintain neutrality
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3
Q

Alkalosis Vs Alkalemia

A

Alkalosis
abnormal process –> HIGHER Arterial pH

  • *Akalemia**
  • *Blood - Arterial pH**

>7.4

(>7.44)

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4
Q
  • *Arterial Blood Gas**
  • *NORMAL VALUES**

pH / PaCO2 / PaO2 / SaO2

Serum Chemistry Panel
HCO3-

A

7.4

40

24

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5
Q

Winter’s Formula

A
  • *PaCO2 = ( 1.5 x HCO3- ) + ( 8 +/- 2 )**
  • measured*

Used to determine PaCO after respiratory compensation
for Metabolic Acidosis

Respiratory comp occurs very quickly

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6
Q

MUD PILES

A

Major causes for
HIGH-ANION-GAP Metabolic Acidosis

Methanol, Uraemia, Diabetes,

Paraldehyde, Iron (and Isoniazid), Lactate,

Ethylene glycol, and Salicylate

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7
Q

Type of Disorder resulting from altercations in

**BICARBONATE = HCO-3
(PaCO2 = acid)**
A

METABOLIC Disorder

Kidneys

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8
Q

What if MEASURED PaCO2 DIFFERS from the PREDICTED value?
(Winter’s Formula)
Metabolic Acidosis –> Respiratory Compensation

If Actual PaCO < Winter’s prediction…

A

concurrent
resipiratory ALKAlosis

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9
Q

Compensation Chart

A
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10
Q

Delta Ratio > 1.6

►AG / ►​HCO3-

A

Change in HCO3 is less than expected from AG change

CONCURRENT METABOLIC ALKALOSIS

Actual HCO3 > Estimated HCO3
MORE BASIC than EXPECTED = Other Alkalosis occuring

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11
Q

Respiratory Acid

A

CO2 EXCRETION
via the Lungs

VCO2 = CO2 Production

VE = Minute Ventilation
(volume of gas inhaled / exhaled per munite)

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12
Q

Simple A-B Disorder

A

SINGLE Primary etiological acid/base disorder
MOST COMMON

—> Mixed acid base disorder
after first presentation

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13
Q

Decreased Respiratory Rate
Cause of Respiratory Acidosis

A

–> Reduced MINUTE Ventilation Ve

WONT BREATHE (respiratory center)
sedative OD
stroke / infection / sleep apnea
anything that depresses medullary control of RR(respiratory rate)

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14
Q

Excess Acid Production
Type of Metabolic Acidosis

A

Extra-Renal Acidosis​

Lactic Acidosis

Ketoacidosis

Ingestions/Infusions = MUDPILES
Toxic Alcohols =
Methanol /eth-glycol / dieth-glycol / prop-glycol
Salicylate Poisoning

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15
Q

Delta Ratio = 1

►AG / ►HCO3-

A

Nothing else going on,
aside from the Metabolic Disorder

(0.8 -1.6)

Change in AG is due to the change in HCO3

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16
Q

Respiratory Compensation
for Metabolic Alkalosis

A
  • Decreased Minute Ventilation*
  • -> INCREASE CO2 (more acidic)

Predicting That Value:
PaCO2 = (0.7 x HCO3‐measured) + 20 +/‐ 5

if Actual CO2 > Predicted CO2
conc. respiratory ACIDosis
since the actual ACID is GREATER than what we expect

if Actual < predicted = “ ALKAlosis

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17
Q

Metabolic Compensation
for Respiratory ALKAlosis

A

decreased retention / regeneration of renal HCO3

2 phase
Acute = decrease 10 mmHG PaCO : 2 mmol/L HCO3
Chronic = decrease 10 : 4
chronic is more efficient

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18
Q

Clinical Interpretation for
PRIMARY AB-Disorders

ph = 7.4

A

More likely than NOT
7.4 ph is MIXED** or **COMPENSATED
rarely 7.4, body will NOT overcompensate

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19
Q

Causes of
METABOLIC ALKALOSIS
increase in HCO3-

A

Hydrogen Ion Loss
absolute or relative from:
intracellular shift / GI loss / Renal loss

Excess admin/retention of HCO3

Volume of CONTRACTION
around a relatively stable amount of HCO3

20
Q

Excess Admin / Retention of HCO3
Cause of Metabolic Alkalosis

A

Sodium Bicarb
ALONG WITH
hypoVOLemia or reduced effective arterial BV or renal impairment

Massive Transfusion of citrated blood
ALONG WITH:
hypoVOLemia or reduced effective arterial BV or renal impairment

21
Q

Anion Gap

A

JUST A MEASUREMENT TOOL

AG = Na+ - (Cl- + HCO3)

~12

Anions - Cations

22
Q

COMPENSATION

Respiratory –helps–> Metabolic

A

when an AB disorder exists –> body atempts to return pH to normal

Metabolic Disturbance –> Lungs try to compensate

OCCURS QUICKLY
munites -> hours

only 1 phase

23
Q

Hydrogen Ion Loss
Cause of Metabolic Alkalosis

A

Intracellular Shift
hypoKALemia (most K is in cells)
extracellular K will get decreased to bring into cell

  • *GI Loss**
  • *Gastric secretions** = vomit / nasogastric suction

Renal Loss
loop or thiazide DIURETICS
lose water / Na / K (lose K, not potassium sparing)

24
Q

Diminished Renal Acid Secretion
Type of Metabolic Acidosis​

A

Renal Acidosis

Distal (TYPE 1) - RTA
Impaired H+ secretion in distal nephron –> progressive retention
normal Anion-gap metabolic acidosis

TYPE 4 = *hypoaldosteronism*
HYPERKalemia + HYPERChloremic metabolic acidosis

Chronic Renal Failure

25
**5 Step Approach** in determining **which AB disorder** a patient is having
**_Is there a Disorder in the contributors_**_?_ HCO3 = 24? // PaCO2 = 40? **_Is there an -EMIA?_** if so ID it excess acid / loss of base --\> ACIDemia **_Primary Metabolic or Respiratory?_** if **pH & PaCO2** are in ***OPPOSITE*** directions = ***RESPIRATORY*** If in **SAME** direction = **METABOLIC** **_If metabolic Disorder.... Acidosis_** calculate **AG** --\> **delta ratio** **_Determine Compensation_**
26
**What if the MEASURED HCO3- DIFFERS from the PREDICTED value?** **Metabolic Compensation** for Respiratory Acidosis
**_Actual \> Predicted Value_** ( Acute (24hr\>x\<72) = 10:1 / Chronic = 10 : 3 ) concurrent metabolic **ALKAlosis** **_Actual \< Predicted Value_** concurrent metabolic **ACIDosis** OR **Not yet compensated** (timing is key, \>24 hours)
27
**Metabolic Compensation** for **Respiratory Acidosis**
**_INCREASED RETENTION_** or **_Regeneration of RENAL HCO3-_** _2 phase w/ metabolic compensation_ **Acute** = increase of **10 mmHg PaCO2 to 1 mmol/L HCO3- Chronic**=**10 : 3** chronic is MORE efficient
28
**Loss of Bicarbonate Base** Type of **Metabolic Acidosis​**
* Extra-Renal Acidosis​* * **_Does NOT cause an ANION GAP_*** **_Gastrointestinal_** Severe **Diarrhea**, **ureteral Diversion** **_Hyperchloremia_** **NaCl**, **CaCl**2, etc bodies attempts to maintain **electrical neutrality**
29
**Clinical Interpretation for PRIMARY AB-Disorders** pH **\> 7.4**
**_Respiratory ALKalosis_** ***decrease in PaCO2*** (acid) **_Metabolic ALKalosis_** **Increase in HCO3-** (base)
30
Causes of **Respiratory ALKAlosis** *decrease in **PaCO2***
Lungs are stimulated to ***remove*** **MORE CO2 than is produced metabolically in the tissues** **_CENTRAL_** **Anxiety / pain / fever** / infection injury / psychosis / **hyperventilation syndrome / delerium** * *_PERIPHERAL_** * *hypoxemic conditions** = **high altitude** / PE * *Induced** = iatragenic hyperventilation / **intoxications**
31
**Clinical Interpretation for PRIMARY AB-Disorders** pH **\<7.4**
**_Respiratory Acidosis_** **increase in PaCO2** (acid) **_Metabolic Acidosis_** ***decrease in HCO3-*** (base)
32
**Renal Loss of Bicarbonate Base** Type of Metabolic Acidosis​
**_PROXIMAL = Type 2 - RTA_** *decrease in **proximal HCO3- reabsorptive capacity*** results in --\> **bicarb wasting** --\> fall in ***serum bicarb conc.***
33
**Volume Contraction around a relatively stable # of HCO3-** Cause of **Metabolic Alkolosis**
***_LOSS of large volume of fluids_*** that has a **HIGH CL-, but a *low HCO3-*** cause to be more BASIC / ALKALINE _HCO3- RISES_ in this setting because there is **contraction of EC Volume** around a constant quantity of **extracellular HCO3** --\> ***CL- simulatneously falls***
34
**What if MEASURED PaCO2 DIFFERS from the PREDICTED value? (**Winter's Formula) Metabolic Acidosis --\> **Respiratory Compensation** If **Actual PaCO \> Winter's prediction...**
concurrent **resipiratory ACIDosis**
35
Causes of **Respiratory Acidosis**
* **_reduced MINUTE VENTILATION_*** * *Ve** = **(RR) x (VT)** * **Decreased Respiratory Rate*** = WONT BREATHE * **decreased VT*** *=* tidal volume, CANT BREATHER * *_Increased Deadspace_** * *VD / VT**
36
**Respiratory Compensation** | (for **Metabolic Acidosis**)
* *INCREASED Minute Ventilation** (**Ve)** - -\> to ***_decrease CO2_*** (acid) **_Winter's Formula_** used to determine **PaCO2 AFTER compensation**
37
**Decreased Vt** (tidal volume) Cause of Respiratory Acidosis
--\> **reduced Minute ventilation Ve = RR x Vt** **_CAN'T BREATHE_** (respiratory **nerve/muscle fxn)** **Diaphragmatic Paralysis** etc.
38
* *Metabolic Acidosis** * decreased HCO3-*
**MOST COMMON** predominant, when INITIALLY presented * *_Extra-Renal Acidosis_** * *Excess Production of Acid * Loss of Bicarbonate Base*** * *_Renal Acidosis_** * **Diminished renal Acid secretion*** * **Renal LOSS of bicarbonate base***
39
**COMPENSATION** **Metabolic --helps--\> Respiratory**
Respiratory Disturbance --\> kidneys come to compensate ***_OCCURS SLOWLY_*** hours - day **_2 Phases_** **Acute // Chronic** \>24 but \<72 hours // \>72 hours
40
What to do if it is a **Metabolic Disorder?** 5-Step Approach
* *_Calculate AG_** * *Corrected AG** = **Observed** AG + **2.5 (4g/dL - obs albumin)** **AG =** Corrected **AG** - Normal **AG (12)** **HCO3- = Normal HCO (24) - measured HCO** **_Delta Ratio = AG / HCO_**
41
**Increased Deadspace** Cause of **Respiratory Acidosis**
Increased **Vd / VT** caused by: **_Anatomic Deadspace_** short / shallow breathing = *decreased Vt* * *_Alveolar Deadspace_** * *parenchymal lung disease** = **COPD** / fibrosis * **decreased perfusion*** = severe **PE** / **vascular disease**
42
**What if the _measured_ HCO3- _differs_ from the _predicted value_?** Metabolic Compensation for Respiratory ALKAlosis
``` Acute = 10 : 2 decrease Chronic = 10 : 4 decrease ``` * *_Actual \> Predicted_** * *NOT YET COMPENSATED** or conc. metabolic **ALKAlosis** **_Actual \< Predicted_** conc metabolic **Acidosis**
43
**Delta Ratio \< 0.8** ►AG / ►​HCO3-
**Change in HCO3 is _MORE_** than the **expected** degree of **AG change** **_CONCURRENT *non-AG***_ _**METABOLIC ACIDOSIS_**
44
**Acidosis** vs **Acidemia**
**Acidosis** abnormal process --\> ***lower ARTERIAL ph*** if left unopposed * *_Acidemia_** * *BLOOD - Arterial pH** **\<7.4 (\<7.36)**
45
**STEP 3** If * *pH** & **PaCO2** * *Same Vs Opposite Direction** What type of **Acid-Base Disorder?**
**pH** & **PaCO2** are in.... * *_SAME DIRECTION_** * *Primary METABOLIC disorder** * **_OPPOSITE DIRECTION_*** * **Primary RESPIRATORY disorder***

PDAT3 (23 decks)

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