Definition: metabolic alkalosis is a clinical disturbance characterized by a high pH (decrease H+ concentration) and a high plasma bicarbonate concentration
It can be produced by a gain of bicarbonate or a loss of H+ (khanna and khurtzman 2001) Probably the most common cause of metabolic alkalosis is vomiting or gastric function with loss of hydrogen and chloride ions
This order also occurs in pyloric stenosis, in which only gastric fluid is lost Gastric fluid has an acid pH (usually 1-3)
Therefore loss of highly acidic fluid increase the alkalinity of body fluids Other loss of K+ such as diuretic therapy that promotes excretion of K+ (furosemide)
Hypokalemia produces alkalosis In two ways
- The kidney conservative potassium
- Cellular K+ moves out of the cell into ECF
Chronic metabolic alkalosis can occur with long term diuretic therapy, villous adenoma, external drainage of gastric fluids, cystic fibrosis and chronic ingestion of milk and calcium carbonate
- Primary symptoms related to decreased calcium ionization such as tingling of the finger and toes, dizziness, and hypertonic muscles Serum Ca+ level decreased in alkalosis as more Ca+ combines with serum proteins
- Respirations are depressed as compensatory action by the lungs
- Arterial tachycardia may occur As pH increases above 7.6 and hypokalemia develops Ventricular disturbance may occur
- Decreased motility and paralytic ileus may also occur Symptoms of chronic metabolic alkalosis are same as for acute metabolic alkalosis
- ABG’s – pH greater than 7.45 and serum bicarbonate concentration greater than 20mEq/L Serum electrolytes – decreased Ca+ + K+
- Treatment aimed at reversing the underlying disorder
- Sufficient chloride must be supplied for kidney to absorb sodium with chloride Restoring normal fluids by Na+Cl fluids
- To maintain alkalosis Administer K+CL
- Histamine – 2 – receptor antagonists (cimitidine)
- Management of chronic metabolic alkalosis is aimed to correct underlying acid- base disorder
Definition: metabolic acidosis is a clinical disturbance characterized by a low pH (increased H+ concentration) and a low plasma bicarbonate concentration
- It can be produced by a gain of hydrogen ion or a loss of bicarbonate (Swenson, 2001)
- It can be divided clinically into two forms according to values of serum anion gap
- High anion gap acidosis
- Normal anion gap acidosis
- Anion gap = Na+ + K+ – (Cl– + HCO3)
- Anion gap = Na+ – (Cl– + HCO3)
- Potassium is often omitted from the equation because of its low level in the plasma
- The normal value for an anion gap is 8 to 12mEq/L (8 – 12 mmol/L) without K+ in the equation
- Normal anion gap acidosis results from the direct loss of bicarbonate as in diarrhea, lower intestinal fistulas, use of divertics
- High anion gap acidosis results from excessive accumulation of fixed acid
- If it increased to 30mEq/L (30mmol/L) or more than a high anion gap metabolic acidosis is present regardless of what the pH and the HCO3 are
- High ion gap occurs in ketoacidosis, lactic acidosis
- Signs and symptoms of metabolic acidosis vary with the severity of the acidosis may include Headache
- Confusion Drowsiness
- Increased respiratory rate and depth Nausea and vomiting
- Peripheral vasodilatation
- And decreased cardiac output occurs when the pH falls below 7 On Examination physical findings
- Low BP
- Cold and Clammy skin Shock (Swenson 2001)
- ABG’s – expected blood gas changes, low bicarbonate level less than 22mEq/L and low pH less than 7.35
- Serum electrolytes Hyperkalemia ECG
- Treatment is directed at correcting the metabolic defects (Swenson 2001) Decrease source of chloride
- Administer bi carbonate if pH level is less 7.1 Serum K+ level monitored closely Hypokalemia is corrected
- In chronic metabolic acidosis low serum Ca+ are treated Hemodialysis or peritoneal dialysis
Definition: respiratory acidosis is a clinical disorder in which the pH is less than 7.35 and the Pco2 is greater than 42mmHg
It may be either:
- Acute respiratory acidosis
- Chronic respiratory acidosis
Respiratory acidosis is always due to inadequate excretion of Co2 with inadequate ventilation, resulting in elevated plasma Co2 levels and thus elevated carbonic acid (H2CO3) levels (Epstein and singh 2001)
Acute respiratory acidosis occurs in emergency situations such as acute pulmonary edema, aspiration of foreign object, atelectasis, pneumothorax, over dose of sedatives, sleep apnea syndrome
Reparatory acidosis can also occur in disease that impair respiratory muscles such as: muscular dystrophy, myasthenia gravis and gullian-ballian syndrome
- Clinical manifestations in acute and chronic respiratory acidosis vary sudden hypercapnia (PaCO2) can cause increased pulse rate
- Increased respiratory rate
- Increased blood pressure
- Mental cloudiness
- Feeling of fullness in the head
- An elevated PaCO2
- Cerebrovascular vasodilatation
- Increased cerebral blood flow particularly when it is higher than 60mmHg
- Ventricular fibrillation may be the first sign of respiratory acidosis
- If respiratory acidosis is severe, intra cranial pressure may increase, resulting in palpation and dilated conjuctival blood vessels
- Chronic respiratory acidosis occurs with pulmonary disease such as:
- Chronic emphysema and bronchitis, obstructive sleep apnea and obesity
- Cyanosis, ICP, tachypnea, COPD
Assessment and Diagnostic Findings
- Arterial blood gas (ABG’s) evaluation reveals a pH less than 7.35 a PaCO2 greater than 42mmHg and variation in the bicarbonate level
- Depending on the duration and cause of the acidosis in acute respiratory acidosis
- Treatment is directed at improving ventilation
- Pharmacological agents are used as indicated e.g bronchodilators, to relieve spasm Antibiotics for infection
- Thrombolytics or anti coagulants are used for pulmonary emboli Adequate hydration
- Mechanical ventilation use appropriately may improve pulmonary ventilation
Respiratory Alkalosis (carbonic acid deficit)
Definition: respiratory alkalosis is a clinical condition in which the arterial pH is greater than 7.45 and the PaCO2 is less than 38mmHg
- As like respiratory acidosis acute and chronic condition can occur
- Respiratory alkalosis is always due to hyperventilation which cause excessive blowing off of CO2 and hence a decrease in the plasma carbonic acid concentration
- Causes can include”
- Extreme anxiety
- Inappropriate ventilator setting
- Chronic respiratory alkalosis results from chronic hypocapnia and decreased serum bicarbonate levels
- Chronic liver insufficiency
- Cerebral tumors are predisposing factors
- Light headedness – due to vasoconstriction and decreased cerebral blood flow
- Inability to concentrate
- Tingling due to decreased calcium
- Tinnitus and at time loss of consciousness
- Arterial dysthermias
- ABG’s assist in the diagnosis of respiratory alkalosis
- In acute state pH is elevated above normal as result of low PaCO2 and normal bicarbonate level
- Serum electrolytes analysis decreased Ca+ level
- Patient with chronic respiratory alkalosis are usually asymptomatic
- Treatment depends on the underlying cause of respiratory alkalosis
- If the cause is anxiety – the patient instructed to breath slowly to allow CO2 to accumulate
- A sedative may be required to relieve hyperventilation in vary anxious patients
- To correct underlying problem
Health Perception–Health Management
• How is your energy level compared with 1 yr ago?
• Do you notice any visual changes?*
• Have you ever smoked? If yes, how many packs per day?
• How is your appetite?
• Has your weight changed over the past yr?*
• Do you take vitamins, herbs, or any other supplements?*
• How much and what kinds of fluids do you drink daily?
• How many dairy products and how much meat do you eat?
• Do you drink coffee? Colas? Tea?
• Do you eat chocolate?
• Do you spice your food heavily?*
• Are you able to sit through a 2-hr meeting or ride in a car for 2 hr without urinating?
• Do you awaken at night with the desire to urinate? If so, how many times does this occur during an average night?
• Do you ever notice blood in your urine?* If so, at what point in the urination does it occur?
• Do you ever pass urine when you do not intend to? When?
• Do you use special devices or supplies for urine elimination or control?*
• How often do you move your bowels?
• Do you ever experience constipation?
• Do you frequently experience diarrhea? Do you ever have problems controlling your bowels? If so, do you have problems controlling the passage of gas? Watery or liquid stool? Solid stool?
• Have you noticed any changes in your ability to do your usual daily activities?*
• Do certain activities aggravate your urinary problem?*
• Has your urinary problem caused you to alter or stop any activity or exercise?*
• Do you require assistance in moving or getting to the bathroom?*
• Do you awaken at night from an urge to urinate?*
• Do you awaken at night from pain or other problems and urinate as a matter of routine before returning to sleep?*
• Do you experience daytime sleepiness and fatigue as a result of nighttime urination?*
• Do you ever have pain when you urinate?* If so, where is the pain?
• How does your urinary problem make you feel about yourself?
• Do you perceive your body differently since you have developed a urinary problem?
• Does your urinary problem interfere with your relationships with family or friends?*
• Has your urinary problem caused a change in your job status or
affected your ability to carry out job-related responsibilities?*
• Has your urinary problem caused any change in your sexual pleasure or performance?*
• Do you have hygiene problems related to sexual activities that cause you concern?*
• Do you feel able to manage the problems associated with your urinary problem? If not, explain.
• What strategies are you using to cope with your urinary problem?
• Has your present illness affected your belief system?*
• Are your treatment decisions related to your urinary problem in conflict with your value system?*