Patients who have been poisoned by CO should be immediately removed from the offending source, and therapy to reverse the tissue hypoxia should be initiated. Removal of CO from the body will be accomplished by the same therapies applied toward relieving tissue hypoxia.
The mainstay of therapy for CO poisoning is the administration of 100 percent oxygen through a tight- fitting nonrebreather mask at a flow rate of 10 L/min. Comatose patients will require endotracheal intubation and mechanical ventilation. If there are signs of inhalation injury, continuous positive airway pressure should be used. In addition to providing for one-third of the bodys total oxygen requirement by simple dissolution in plasma, 100 percent oxygen also reduces the half-life of CO in the body to approximately 40 to 80 minutes from the 240-minute half-life of CO when breathing normal room air.
The use of hyperbaric oxygen at 2.5 to 3 atm of pressure has been advocated recently. In addition to reducing the half-life of CO to 20 to 25 minutes, oxygen at these pressures dissolves in plasma to concentrations that are sufficient to meet total body oxygen requirements in the absence of functioning hemoglobin. Proponents of hyperbaric oxygen therapy contend that its use reduces morbidity, especially that related to delayed neurologic sequelae, and that hyperbaric oxygen therapy is useful even if treatment is delayed for 20 hours after exposure. In a retrospective review, Norkool and Kirkpatrick found the rate of sequelae in patients treated with hyperbaric oxygen to be one-fourth that of the rate found in a previous study in which patients had not received this therapy. Cialis Jelly
Table 2—Severities of CO Poisoning
Mild poisoning Criteria:
COHb levels <30 percent No signs or symptoms of impaired cardiovascular or neurologic (unction May complain of headache, nausea, or vomiting Treatment: Admission of patients with COHb levels >25 percent Symptomatic medication
100 percent oxygen by nonrebreathing mask until COHb remains <5 percent
Patients with underlying heart disease should be admitted and cardiac (unction be appropriately monitored regardless of COHb level. Moderate poisoning Criteria:
COHb levels from 30 to 40 percent
No signs or symptoms of impaired cardiovascular or neurologic
(unction Treatment: Admission
Cardiovascular status should be followed closely even in absence of clear cardiac effects, especially in those patients with underlying heart disease. Determination of acid-base status (will be corrected by high-flow oxygen)
100 percent oxygen by nonrebreathing mask until COHb remains <5 percent Severe poisoning Criteria: COHb levels >40 percent or
Cardiovascular or neurologic functional impairment at any COHb
Cardiovascular (unction monitoring Acid-base status monitoring 100 percent oxygen by nonrebreathing mask Transport to a hyperbaric oxygen facility, immediately if available, or if no improvement in cardiovascular or neurologic (unction is seen in within 4 h)
One drawback of hyperbaric oxygen therapy is that it is not readily available. Concern has been expressed regarding the transfer of patients in unstable condition or potentially unstable condition to a hyperbaric oxygen facility that may be quite a distance away. Cuidelines put forth by Dolan suggest that comatose patients with high levels of COHb remain at the original hospital of admission until levels fall to below 9 percent; if they remain comatose or begin to present with neurologic symptoms, only then should transport to a distant center be considered. In transport, 100 percent oxygen should be continued via mask.
As a strong proponent of hyperbaric oxygen therapy, Kirkpatrick advocates the use of this treatment immediately in any patient with COHb levels greater than 40 percent and in any patient exhibiting neurologic problems other than mild headache and nausea. A prior history of unconsciousness and cardiac abnormalities would also be cause for referral. canadian cialis online
The treatment of CO poisoning can be separated into three categories: treatment for mild poisoning, moderate poisoning, and severe poisoning (Table 2). In mild poisoning, COHb levels are below 30 percent, and there are no signs or symptoms demonstrating reduced cardiovascular or neurologic function. Patients may complain of headache, nausea, and vomiting, and these may be treated with the appropriate medication. Treatment consists of administration of 100 percent oxygen through a nonrebreathing mask until COHb levels fall below 5 percent. Patients with underlying heart disease should be admitted and cardiac (unction closely monitored.
In moderate poisoning, COHb levels range from 30 percent to 40 percent with no cardiac or neurologic dysfunction; however, cardiovascular status should be closely followed even in the absence of cardiac effects, particularly in those patients with underlying heart disease. Acid-base status should be determined owing to the possible buildup of lactic acid resulting from the lack of oxygen and dependence upon anaerobic metabolism. Administration of 100 percent oxygen is continued until COHb levels fall below 5 percent and all signs and symptoms of poisoning have resolved.
In severe poisoning, COHb levels are greater than 40 percent, or cardiovascular or CNS symptoms are evident. If a hyperbaric oxygen chamber is readily available, patients should be immediately transported to the facility. If not, these individuals should be treated the same as the moderately poisoned. If improvement is not seen in four hours with administration of 100 percent oxygen via mask, they should be transported to the nearest hyperbaric oxygen facility regardless of transport time. Supportive therapy more than likely will be required, with cardiac monitoring a must.
Whether hyperbaric oxygen is used or not, it is essential to admit all patients with COHb levels greater than 25 percent, those patients with a history of heart disease and COHb levels greater than 15 percent, and any patients presenting with ECG evidence of ischemia, impaired mental function, or neurologic symptoms. Patients not fitting into these groups can be treated with 100 percent normobaric oxygen until their COHb levels fall below 5 percent and any symptoms wane. After such treatment is completed, COHb levels may rise again several hours later due to slow release of CO from the tissues. Therefore, conservative therapy for patients treated with 100 percent normobaric oxygen should include prolonged administration of high-flow oxygen with serial determinations of COHb levels. eriacta tablets