Details About Overdose or Poisoning Generic Salt :: Oxygen And Hyperbaric Oxygen
Oxygen and Hyperbaric Oxygen
Drug Pharmacology ::
I. Pharmacology. Oxygenis a necessary oxidant to drive biochemical reactions. Room aircontains 21% oxygen. Hyperbaric oxygen (HBO) (100% oxygen delivered tothe patient in a pressurized chamber at 2–3 atm of pressure) may bebeneficial for patients with severe carbon monoxide (CO) poisoning. Itcan hasten the reversal of CO binding to hemoglobin and intracellularmyoglobin, can provide oxygen independent of hemoglobin, and may haveprotective actions in reducing postischemic brain damage. Randomizedcontrolled studies have reported conflicting outcomes with HBOtreatment, but there appears to be at least a marginal benefit inpreventing subtle neuropsychiatric sequelae.
Drug Indications ::
Supplementaloxygen is indicated when normal oxygenation is impaired because ofpulmonary injury, which may result from aspiration (chemicalpneumonitis) or inhalation of toxic gases. The PO2 should be maintained at 70–80 mm Hg or higher if possible.
Supplemental oxygen usually is given empirically to patients with altered mental status or suspected hypoxemia.
Oxygen(100%) is indicated for patients with carbon monoxide poisoning, toincrease the conversion of carboxyhemoglobin and carboxymyoglobin tohemoglobin and myoglobin, and to increase oxygen saturation of theplasma and subsequent delivery to tissues.
Hyperbaricoxygen may be beneficial for patients with severe carbon monoxidepoisoning, although the clinical evidence is mixed. Potentialindications include history of loss of consciousness; metabolicacidosis, age over 50 years, pregnancy, carboxyhemoglobin level greaterthan 25%, and cerebellar dysfunction (eg, ataxia).
E.HBO has also been advocated for treatment of poisoning by carbontetrachloride, cyanide, and hydrogen sulfide and for severemethemoglobinemia, but the experimental and clinical evidence is scanty.
Drug Contra-Indications ::
In paraquat poisoning, oxygen may contribute to lung injury. In fact, slightly hypoxic environments (10–12% oxygen) have been advocated to reduce the risk of pulmonary fibrosis from paraquat.
Relativecontraindications to hyperbaric oxygen therapy include a history ofrecent middle ear or thoracic surgery, untreated pneumothorax, seizuredisorder, and severe sinusitis.
Drug Adverse Effects ::
IV. Adverse effects. Caution: Oxygen is extremely flammable.
Prolongedhigh concentrations of oxygen are associated with pulmonary alveolartissue damage. In general, the fraction of inspired oxygen (FIO2) should not be maintained at greater than 80% for more than 24 hours.
Oxygen therapy may increase the risk of retrolental fibroplasia in neonates.
Administrationof high oxygen concentrations to patients with severe chronicobstructive pulmonary disease and chronic carbon dioxide retention whoare dependent on hypoxemia to provide a drive to breathe may result inrespiratory arrest.
Hyperbaric oxygen treatment can cause hyperoxic seizures, aural trauma(ruptured tympanic membrane), and acute anxiety resulting fromclaustrophobia. Seizures are more likely at higher atmosphericpressures (eg, 3 atm or greater).
E.Oxygen may potentiate toxicity via enhanced generation of free radicalswith some chemotherapeutic agents (eg, bleomycin, Adriamycin, anddaunorubicin).
F. Use in pregnancy. No known adverse effects.
Drug Lab Interactions ::
Drug or laboratory interactions. None known.
Drug Dose Management ::
Dosage and method of administration
Supplemental oxygen. Provide supplemental oxygen to maintain a PO2 of at least 70–80 mm Hg. If a PO2 greater than 50 mm Hg cannot be maintained with an FIO2 of at least 60%, consider positive end-expiratory pressure or continuous positive airway pressure.
Carbon monoxide poisoning. Provide 100% oxygen by tight-fitting mask or via endotracheal tube. Consider hyperbaric oxygen therapyif the patient has serious poisoning (see Indications, above) and thepatient can be treated within 6 hours of the exposure. Consult with apoison center ( 222-1222) or a hyperbaric specialist to determinethe location of the nearest HBO facility. Usually, three HBO treatmentsat 2.5–3 atm are recommended over a 24-hour period.
Drug Chemical Formulations ::
Nasal cannula. Provides 24–40% oxygen, depending on the flow rate and patient’s breathing pattern.
Ventimask. Provides variable inspired oxygen concentrations from 24 to 40%.
Nonrebreathing reservoir mask. Provides 60–90% inspired oxygen concentrations.
Hyperbaric oxygen. One hundred percent oxygen can be delivered at a pressure of 2–3 atm.