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Respiratory alkalosis is very rarely life-threatening, though pH level should not be 7.5 or greater. The aim in treatment is to detect the underlying cause. When PaCO2 is adjusted rapidly in individuals with chronic respiratory alkalosis, metabolic acidosis may occur. If the individual is on a mechanical ventilator then preventing hyperventilation is done via monitoring ABG levels.
A pH under 7.1 is an emergency, due to the risk of cardiac arrhythmias, and may warrant treatment with intravenous bicarbonate. Bicarbonate is given at 50-100 mmol at a time under scrupulous monitoring of the arterial blood gas readings. This intervention, however, has some serious complications in lactic acidosis, and in those cases, should be used with great care.
If the acidosis is particularly severe and/or intoxication may be present, consultation with the nephrology team is considered useful, as dialysis may clear both the intoxication and the acidosis.
Respiratory stimulants such as nikethamide were traditionally used to counteract respiratory depression from CNS depressant overdose, but offered limited effectiveness. A new respiratory stimulant drug called BIMU8 is being investigated which seems to be significantly more effective and may be useful for counteracting the respiratory depression produced by opiates and similar drugs without offsetting their therapeutic effects.
If the respiratory depression occurs from opioid overdose, usually an opioid antagonist, most likely naloxone, will be administered. This will rapidly reverse the respiratory depression unless complicated by other depressants. However an opioid antagonist may also precipitate an opioid withdrawal syndrome in chronic users.
In people with stable OHS, the most important treatment is weight loss—by diet, through exercise, with medication, or sometimes weight loss surgery (bariatric surgery). This has been shown to improve the symptoms of OHS and resolution of the high carbon dioxide levels. Weight loss may take a long time and is not always successful. Bariatric surgery is avoided if possible, given the high rate of complications, but may be considered if other treatment modalities are ineffective in improving oxygen levels and symptoms. If the symptoms are significant, nighttime positive airway pressure (PAP) treatment is tried; this involves the use of a machine to assist with breathing. PAP exists in various forms, and the ideal strategy is uncertain. Some medications have been tried to stimulate breathing or correct underlying abnormalities; their benefit is again uncertain.
While many people with obesity hypoventilation syndrome are cared for on an outpatient basis, some deteriorate suddenly and when admitted to the hospital may show severe abnormalities such as markedly deranged blood acidity (pH<7.25) or depressed level of consciousness due to very high carbon dioxide levels. On occasions, admission to an intensive care unit with intubation and mechanical ventilation is necessary. Otherwise, "bi-level" positive airway pressure (see the next section) is commonly used to stabilize the patient, followed by conventional treatment.
Positive airway pressure, initially in the form of "continuous" positive airway pressure (CPAP), is a useful treatment for obesity hypoventilation syndrome, particularly when obstructive sleep apnea co-exists. CPAP requires the use during sleep of a machine that delivers a continuous positive pressure to the airways and preventing the collapse of soft tissues in the throat during breathing; it is administered through a mask on either the mouth and nose together or if that is not tolerated on the nose only (nasal CPAP). This relieves the features of obstructive sleep apnea and is often sufficient to remove the resultant accumulation of carbon dioxide. The pressure is increased until the obstructive symptoms (snoring and periods of apnea) have disappeared. CPAP alone is effective in more than 50% of people with OHS.
In some occasions, the oxygen levels are persistently too low (oxygen saturations below 90%). In that case, the hypoventilation itself may be improved by switching from CPAP treatment to an alternate device that delivers "bi-level" positive pressure: higher pressure during inspiration (breathing in) and a lower pressure during expiration (breathing out). If this too is ineffective in increasing oxygen levels, the addition of oxygen therapy may be necessary. As a last resort, tracheostomy may be necessary; this involves making a surgical opening in the trachea to bypass obesity-related airway obstruction in the neck. This may be combined with mechanical ventilation with an assisted breathing device through the opening.
Acute respiratory distress syndrome is usually treated with mechanical ventilation in the intensive care unit (ICU). Mechanical ventilation is usually delivered through a rigid tube which enters the oral cavity and is secured in the airway (endotracheal intubation), or by tracheostomy when prolonged ventilation (≥2 weeks) is necessary. The role of non-invasive ventilation is limited to the very early period of the disease or to prevent worsening respiratory distress in individuals with atypical pneumonias, lung bruising, or major surgery patients, who are at risk of developing ARDS. Treatment of the underlying cause is crucial. Appropriate antibiotic therapy must be administered as soon as microbiological culture results are available, or clinical infection is suspected (whichever is earlier). Empirical therapy may be appropriate if local microbiological surveillance is efficient. The origin of infection, when surgically treatable, must be removed. When sepsis is diagnosed, appropriate local protocols should be enacted.
Inhaled nitric oxide (NO) selectively widens the lung's arteries which allows for more blood flow to open alveoli for gas exchange. Despite evidence of increased oxygenation status, there is no evidence that inhaled nitric oxide decreases morbidity and mortality in people with ARDS. Furthermore, nitric oxide may cause kidney damage and is not recommended as therapy for ARDS regardless of severity.
Oxygen is given with a small amount of continuous positive airway pressure ("CPAP"), and intravenous fluids are administered to stabilize the blood sugar, blood salts, and blood pressure. If the baby's condition worsens, an endotracheal tube (breathing tube) is inserted into the trachea and intermittent breaths are given by a mechanical device. An exogenous preparation of surfactant, either synthetic or extracted from animal lungs, is given through the breathing tube into the lungs. Some of the most commonly used surfactants are Survanta or its generic form Beraksurf, derived from cow lungs, which can decrease the risk of death in hospitalized very-low-birth-weight infants by 30%. Such small premature infants may remain ventilated for months. A study shows that an aerosol of a perfluorocarbon such as perfluoromethyldecalin can reduce inflammation in swine model of IRDS. Chronic lung disease including bronchopulmonary dysplasia are common in severe RDS. The etiology of BPD is problematic and may be due to oxygen, overventilation or underventilation. The mortality rate for babies greater than 27 weeks gestation is less than 20%
Extracorporeal membrane oxygenation (ECMO) is a potential treatment, providing oxygenation through an apparatus that imitates the gas exchange process of the lungs. However, newborns cannot be placed on ECMO if they are under 4.5 pounds (2 kg), because they have extremely small vessels for cannulation, thus hindering adequate flow because of limitations from cannula size and subsequent higher resistance to blood flow (compare with vascular resistance). Furthermore, in infants aged less than 34 weeks of gestation several physiologic systems are not well-developed, specially the cerebral vasculature and germinal matrix, resulting in high sensitivity to slight changes in pH, PaO, and intracranial pressure. Subsequently, preterm infants are at unacceptably high risk for intraventricular hemorrhage (IVH) if administered ECMO at a gestational age less than 32 weeks.
- The INSURE Method
Henrik Verder is the inventor and pioneer of the INSURE method, a very effective approach to managing preterm neonates with respiratory distress. The method itself has been shown, through meta-analysis; to successfully decrease the use of mechanical ventilation and lower the incidence of bronchopulmonary dysplasia (BPD). Since its conception in 1989 the INSURE method has been academically cited in more than 500 papers. The first randomised study about the INSURE method was published in 1994 and a second randomised study in infants less than 30 weeks gestation was published by the group in 1999. In the last 15 years Henrik has worked with lung maturity diagnostics on gastric aspirates obtained at birth. By combining this diagnostic method with INSURE, Henrik has worked to further improve the clinical outcome of RDS. The lung maturity tests used have been the microbubble test, lamellar body counts (LBC) and measurements of lecithin-sphingomyelin ratio (L/S) with chemometrics, which involved a collaboration with Agnar Höskuldsson.
Severe cases require hemodialysis or hemofiltration, which are the most rapid methods of removing potassium from the body. These are typically used if the underlying cause cannot be corrected swiftly while temporizing measures are instituted or there is no response to these measures.
Potassium can bind to agents in the gastrointestinal tract. Sodium polystyrene sulfonate with sorbitol (Kayexalate) has been approved for this use and can be given by mouth or rectally. However, careful clinical trials to demonstrate the effectiveness of sodium polystyrene are lacking, and use of sodium polystyrene sulfonate, particularly if with high sorbitol content, is uncommonly but convincingly associated with colonic necrosis. There are no systematic studies (>6 months) looking at the long-term safety of this medication. Another medication by the name of patiromer was approved in 2015.
Loop diuretics (furosemide, bumetanide, torasemide) and thiazide diuretics (e.g., chlorthalidone, hydrochlorothiazide, or chlorothiazide) can increase kidney potassium excretion in people with intact kidney function.
Fludrocortisone, a synthetic mineralocorticoid, can also increase potassium excretion by the kidney in patients with functioning kidneys. Trials of fludrocortisone in patients on dialysis have shown it to be ineffective.
Patiromer is a selective sorbent that is taken by mouth and works by binding free potassium ions in the gastrointestinal tract and releasing calcium ions for exchange, thus lowering the amount of potassium available for absorption into the bloodstream and increasing the amount that is excreted via the feces. The net effect is a reduction of potassium levels in the blood serum.
Several medical treatments shift potassium ions from the bloodstream into the cellular compartment, thereby reducing the risk of complications. The effect of these measures tends to be short-lived, but may temporize the problem until potassium can be removed from the body.
- Insulin (e.g. intravenous injection of 10-15 units of regular insulin along with 50 ml of 50% dextrose to prevent the blood sugar from dropping too low) leads to a shift of potassium ions into cells, secondary to increased activity of the sodium-potassium ATPase. Its effects last a few hours, so it sometimes must be repeated while other measures are taken to suppress potassium levels more permanently. The insulin is usually given with an appropriate amount of glucose to prevent hypoglycemia following the insulin administration.
- Salbutamol (albuterol), a β-selective catecholamine, is administered by nebulizer (e.g. 10–20 mg). This medication also lowers blood levels of K by promoting its movement into cells.
- Sodium bicarbonate may be used with the above measures if it is believed the person has metabolic acidosis.
In renal compensation, plasma bicarbonate rises 3.5 mEq/L for each increase of 10 mm Hg in "Pa"CO. The expected change in serum bicarbonate concentration in respiratory acidosis can be estimated as follows:
- Acute respiratory acidosis: HCO increases 1 mEq/L for each 10 mm Hg rise in "Pa"CO.
- Chronic respiratory acidosis: HCO rises 3.5 mEq/L for each 10 mm Hg rise in "Pa"CO.
The expected change in pH with respiratory acidosis can be estimated with the following equations:
- Acute respiratory acidosis: Change in pH = 0.008 X (40 − "Pa"CO)
- Chronic respiratory acidosis: Change in pH = 0.003 X (40 − "Pa"CO)
Respiratory acidosis does not have a great effect on electrolyte levels. Some small effects occur on calcium and potassium levels. Acidosis decreases binding of calcium to albumin and tends to increase serum ionized calcium levels. In addition, acidemia causes an extracellular shift of potassium, but respiratory acidosis rarely causes clinically significant hyperkalemia.
As a side effect of medicines or recreational drugs, hypoventilation may become potentially life-threatening. Many different central nervous system (CNS) depressant drugs such as ethanol, benzodiazepines, barbiturates, GHB, sedatives and opioids produce respiratory depression when taken in large or excessive doses, or mixed with other depressants. Strong opiates (such as fentanyl, heroin, or morphine), barbiturates, and certain benzodiazepines (short acting ones and alprazolam) are known for depressing respiration. In an overdose, an individual may cease breathing entirely (go into respiratory arrest) which is rapidly fatal without treatment. Opioids, in overdose or combined with other depressants, are notorious for such fatalities.
Respiratory acidosis is a medical emergency in which decreased ventilation (hypoventilation) increases the concentration of carbon dioxide in the blood and decreases the blood's pH (a condition generally called acidosis).
Carbon dioxide is produced continuously as the body's cells respire, and this CO will accumulate rapidly if the lungs do not adequately expel it through alveolar ventilation. Alveolar hypoventilation thus leads to an increased "Pa"CO (a condition called hypercapnia). The increase in "Pa"CO in turn decreases the HCO/"Pa"CO ratio and decreases pH.
Giving the mother glucocorticoids speeds the production of surfactant. For very premature deliveries, a glucocorticoid is given without testing the fetal lung maturity. The American College of Obstetricians and Gynecologists (ACOG), Royal College of Medicine, and other major organizations have recommended antenatal glucocorticoid treatment for women at risk for preterm delivery prior to 34 weeks of gestation. Multiple courses of glucocorticoid administration, compared with a single course, does not seem to increase or decrease the risk of death or neurodevelopmental disorders of the child.
In pregnancies of greater than 30 weeks, the fetal lung maturity may be tested by sampling the amount of surfactant in the amniotic fluid by amniocentesis, wherein a needle is inserted through the mother's abdomen and uterus. Several tests are available that correlate with the production of surfactant. These include the lecithin-sphingomyelin ratio ("L/S ratio"), the presence of phosphatidylglycerol (PG), and more recently, the surfactant/albumin (S/A) ratio. For the L/S ratio, if the result is less than 2:1, the fetal lungs may be surfactant deficient. The presence of PG usually indicates fetal lung maturity. For the S/A ratio, the result is given as mg of surfactant per gm of protein. An S/A ratio 55 indicates mature surfactant production(correlates with an L/S ratio of 2.2 or greater).
In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.20 to 7.38). In the fetus, the lungs are not used for ventilation. Instead, the placenta performs ventilatory functions (gas exchange). Fetal respiratory acidemia is defined as an umbilical vessel pH of less than 7.20 and an umbilical artery PCO of 66 or higher or umbilical vein PCO of 50 or higher.
Direct removal of lactate from the body (e.g. with hemofiltration) is difficult, with limited evidence for benefit. In type A lactic acidosis, treatment consists of effective management of the underlying cause, and limited evidence supports the use of sodium bicarbonate solutions to improve the pH (which is associated with increased carbon dioxide generation and may reduce the calcium levels).
In type B lactic acidosis produced by medication, withdrawal of the medication may be necessary to resolve the lactic acidosis.
Lactic acidosis in the context of mitochondrial disorders (type B3) may be treated with a ketogenic diet and possibly with dichloroacetate (DCA), although this may be complicated by peripheral neuropathy and has a weak evidence base.
Treatment of uncompensated metabolic acidosis is focused upon correcting the underlying problem. When metabolic acidosis is severe and can no longer be compensated for adequately by the lungs, neutralizing the acidosis with infusions of bicarbonate may be required.
Treatment consists of oral bicarbonate supplementation. However, this will increase urinary bicarbonate wasting and may well promote a bicarbonate . The amount of bicarbonate given may have to be very large to stay ahead of the urinary losses. Correction with oral bicarbonate may exacerbate urinary potassium losses and precipitate hypokalemia. As with dRTA, reversal of the chronic acidosis should reverse bone demineralization.
Thiazide diuretics can also be used as treatment by making use of contraction alkalosis caused by them.
In closed circuit SCUBA (rebreather) diving, exhaled carbon dioxide must be removed from the breathing system, usually by a scrubber containing a solid chemical compound with a high affinity for CO, such as soda lime. If not removed from the system, it may be re-inhaled, causing an increase in the inhaled concentration.
This is relatively straightforward. It involves correction of the acidemia with oral sodium bicarbonate, sodium citrate or potassium citrate. This will correct the acidemia and reverse bone demineralisation. Hypokalemia and urinary stone formation and nephrocalcinosis can be treated with potassium citrate tablets which not only replace potassium but also inhibit calcium excretion and thus do not exacerbate stone disease as sodium bicarbonate or citrate may do.
Although the etiology is unconfirmed, transient hyperammonemia is known to be caused by increased levels of ammonia in the blood stream, as well as a failure of the urea cycle to convert enough of the ammonia into urea. Since transamination of proteins is a leading producer of ammonia, protein restriction may be recommended as a therapy to reduce the symptoms of the episode. THAN can also be treated by avoiding amino acids in TPN or total parenteral nutrition or by giving a high caloric diet to limit catabolism of the tissues and therefore to minimize the breakdown of endogenous protein. The most common treatments are dialysis (both peritoneal and hemodialysis), sodium benzoate, and arginine. Sodium Benzoate combines with glycine to be excreted in the form of hippuric acid. The goal of these treatments is to convert nitrogen to a compound that can be excreted more easily.
The underlying cause determines the prognosis of lactic acidosis. In sepsis, elevated lactate levels correlate with mortality. The mortality of lactic acidosis in people taking metformin was previously reported to be 50%, but in more recent reports this was closer to 25%.
There is no proven treatment for congenital lactic acidosis. Treatments that are occasionally used or that are under investigation include the ketogenic diet and dichloroacetate. Other treatments aim to relieve symptoms – for example, anticonvulsants may be used to relieve seizures.
Hyperbaric oxygen is also used in the treatment of carbon monoxide poisoning, as it may hasten dissociation of CO from carboxyhemoglobin and cytochrome oxidase to a greater extent than normal oxygen. Hyperbaric oxygen at three times atmospheric pressure reduces the half life of carbon monoxide to 23 (~80/3 minutes) minutes, compared to 80 minutes for oxygen at regular atmospheric pressure. It may also enhance oxygen transport to the tissues by plasma, partially bypassing the normal transfer through hemoglobin. However, it is controversial whether hyperbaric oxygen actually offers any extra benefits over normal high flow oxygen, in terms of increased survival or improved long-term outcomes. There have been randomized controlled trials in which the two treatment options have been compared; of the six performed, four found hyperbaric oxygen improved outcome and two found no benefit for hyperbaric oxygen. Some of these trials have been criticized for apparent flaws in their implementation. A review of all the literature on carbon monoxide poisoning treatment concluded that the role of hyperbaric oxygen is unclear and the available evidence neither confirms nor denies a medically meaningful benefit. The authors suggested a large, well designed, externally audited, multicentre trial to compare normal oxygen with hyperbaric oxygen.
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide. This condition is one of the four basic categories of disruption of acid–base homeostasis.