Detailed presentation about Respiratory alkalosis. its defination, causes, symptoms, treatments and its relation to acid bases disorder.

1. RESPIRATORY
ALKALOSIS
By: Arish Ayub
American university of barbados

2. INTRODUCTION
• Respiratory alkalosis is a condition where the amount of PaCO2 found in the blood
drops to a level below normal range.
• This condition produces a shift in the body's pH balance and causes the body's system
to become more alkaline (basic).
• caused due to deep breathing called hyperventilation.
• It is also caused due to disturbance in acid and bases balance due to alveolar
hypertension.

3. Normal Pathway

4. • In case of Respiratory Alkalosis more
amount of co2 is expelled out.
• Which in turn raises the level of
bicarbonate ion conc.
• In turn to compensate the level of hco3
ions
• Kidney excretes the excess of bicarbonate.
Cont…

5. How it is caused
• Alveolar hypertension leads to
decrease in PaCo2
• decrease in PaCo2 increases the
ratio of Bicarbonate conc. to
PaCo2
• which in turn increases pH level
of blood.

6. • Alveolar hypertension leads to decrease in PaCo2, so the
decrease in PaCo2 increases the ratio of Bicarbonate conc. to
PaCo2 and there by increases pH level of blood thus, term as
Respiratory Alkalosis.
• Alkalosis can be of two types –
1. Acute
2. Chronic

7. •Acute – In acute PaCo2 level is below lower limit of normal
and the serum pH is alkalemic.
•Chronic – In this the PaCo2 level is below the lower level
of normal but the pH level is relatively normal or near
normal.

8. ETIOLOGY
1. Respiratory centre stimulation
2. Hypoxemia Acute
Chronic
3. Cardiopulmonary diseases Pulmonary diseases
Cardiac diseases
4. Mechanic Hyperventilation

9. PATHOPHYSIOLOGY
• Most cases of respiratory alkalosis reflects an increase in alveolar
ventilation.
• Decrease in PaCo2 equals to decrease in Alveolar ventilation.
• It Alkaline the body fluid.
• So decrease in Bicarbonate Conc. that reduces the impact of
Hypocapnia on systemic acidity.

10. • Two types of adaptations Acute
chronic
1. Acute – It is completed within 5 to 10 min of Hypocapnia
Originates principally from Alkaline Titration of the body non
bicarbonate buffers.
2. Chronic – It requires 2 to 3 days of sustained Hypocapnia completion.
Originates from down regulation of renal acidification mechanism
that results in decrease in urinary net acid excretion and decrease in rate of
renal bicarbonate reabsorption.

11. SIGNS AND SYMPTOMS
• Symptoms and signs depend on the rate and degree of fall in PCO2.
Acute respiratory alkalosis causes light-headedness, confusion,
cramps, and syncope. Mechanism is thought to be as a result of
change in cerebral blood flow and pH. Tachypnea or hyperpnea is
often the only sign; carpopedal spasm may occur in severe cases due
to decreased levels of ionized calcium in the blood (driven inside
cells in exchange for hydrogen ion [H+]).
• Chronic respiratory alkalosis is usually asymptomatic and has no
distinctive signs.

12. APPROACH
Respiratory alkalosis may produce a variety of clinical manifestations, ranging
from mild symptoms to fatal outcome, due to direct effects or secondary electrolyte
disturbances.
Respiratory alkalosis can be classified clinically into 3 categories:
1. As a component of disease processes
2. Induced accidentally
3. Induced deliberately (therapeutic).
• Accidental respiratory alkalosis develops as a consequence of inappropriate settings
of mechanical ventilation or associated with extracorporeal membrane oxygenation
(ECMO).

13. ARTERIAL BLOOD GAS (ABG) ANALYSIS
Value Normal range Clinical significance
pH 7.35-7.45 The pH tells you if your patient is acidotic or
alkalotic. It is a measurement of the acid content or
hydrogen ions [H+] in the blood. A high pH
indicates a lower concentration of hydrogen ions
(alkalosis).
PaCO2 35-45 mm Hg The PaCO2 level is the respiratory component of
the ABG. It is a measurement of carbon dioxide
(CO2) in the blood and is affected by CO2 removal
in the lungs. A low PaCO2 level indicates alkalosis.

14. ARTERIAL BLOOD GAS ANALYSIS
• In summary, if pH > 7.45 and PaCO2 < 35mmHg and the HCO3-
level is normal, the patient has respiratory alkalosis.

15. CAUSES /ILLNESS
 The main causes of Respiratory Alkaloisis or Hyperventillation are as
follows:-
a) Temperature increase in body(Fever)
b) Aspirin Toxicity
c) Controlled mechanical ventillation
d) Hyperventillation
e) Hysteria
f) Pain
g) Neurological injuries
h) Embolism
i) Asthma

17. • Many patients with hyperventillation syndrome appear anxious and
are frequently tachycardic.
understandably, tachypnea is a frequent finding.
• In acute hyperventillation, chest wall movement and breathing rate
increases. In patients with chronic hyperventillation, these physical
finding may not be as obvious.
• The hyperventillation syndrome can mimic many conditions that are
more serious. Symptoms may include paresthesias, circumoral
mumbness ,chest pain or tightness, dyspnea and tetany.

18. • Cardiovascular effects of hypocapnia in healthy and alert patients are minimal, but
in patients who is anesthetized , critically ill , or receiving mechanical ventillation ,
the effect can be more significant. Cardiac output and systemic blood pressure may
fall as a result of the effects of sedation and positive pressure ventillation on
venous return systemic vascular resistence and heart rate.

19. • Cardiac rhythm disturbance may occur because of increased
tissue hypoxia related to the leftward shift of the
hemoglobin-oxygen dissociation curve.

20. SUMMARY
 CNS causes are as follows:-
Pain,Hyperventillation,Anxiety,Panicdisorders,Psychosis,Fever,Cerebrovascularacci
dent, Meningitis, Encephalitis, Tumor, Trauma etc.
 Hypoxic-related causes are as follows:-
High altitude and right to left shunts
 Drug- related causes are as follows:-
Progesterone,Methylxanthine toxicity, Salicylic toxicity, Catecholamines,
Nicotine etc.
 Endocrine related causes are as follows:-
Pregnancy and hyperthyroidism

21.  Pulmonary causes are as follows:-
Pneumothorax, Pneumonia, Pulmonary edema, Pulmonary embolism, Aspiration,
Interstitial lung diseases, asthma, Emphysema, Chronic bronchitis etc.
 Miscellaneous causes are as follows :-
Sepsis, Severe anemia, Hepatic failure, Mechanical ventillation, Heat exhaustion,
Recovery phase of metabolic acidosis, Congestine heart failure etc.

22. • Breathe into a paper bag
• Fill the paper bag with carbon dioxide by exhaling into it.
• Breathe the exhaled air from the bag back into the lungs.
• Repeat this several times.
• Restrict oxygen intake into the lungs
• by closing one of the nostrils, so the lesser amount of oxygen enters the lungs
for mankind the co2 and o2 conc equal.
Treatment

24. • High altitude sickness is treated with acetazolamide 250mg 12 hourly,
Dexamethasone 4mg 6 hourly, oxygen therapy and descent to lower altitude
in severe cases.
• For critically ill patients on mechanical ventilation with respiratory alkalosis,
tidal volume and respiratory rate needs to be decreased with adequate pain
control.
• Sedatives and antidepressants should not be used in cases of respiratory
alkalosis.

25. REFERENCES
• Berend K, de Vries AP, Gans RO. Physiological approach to assessment of acid-
base disturbances. N Engl J Med. 2014;371:1434-1445.
• Androgue HJ, Madias NE. Management of life-threatening acid-base disorders:
second of two parts. N Engl J Med. 1998;338:107-111.
• Byrne, G. (2015). MedScape. Nursing Standard, 29(51), 29-29.
doi:10.7748/ns.29.51.29.s34