Carbon Monoxide Poisoning Combo

Treatment-Medications

100% oxygen with a nonrebreather mask; hyperbaric oxygen therapy I.V. fluid therapy as appropriate to restore volume

Pathogenesis of CO poisoning.

CO combines with Hb to produce COHb, affinity 200-230 more times for oxygen. Decrease of oxygen carrying capacity of blood Alteration of oxyhemoglobin dissociation curve

carboxyhemoglobin

CO that has bound to Hb

Diagnostic Test Results-Laboratory

Carboxyhemoglobin levels are elevated. Arterial blood gas (ABG) analysis reveals a normal or slightly decreased partial pressure of arterial CO2 and metabolic acidosis. Troponin and creatine kinase levels may be elevated, reflecting myocardial ischemia that's commonly associated with CO exposure. Complete blood count may reveal mild leukocytosis. Serum potassium levels may be decreased and blood glucose levels may be elevated (in severe poisoning). Urinalysis may be positive for albumin and glucose with chronic exposure. Blood urea nitrogen and creatinine levels may be elevated secondary to myoglobulinuria.

What diagnostic tests are indicated in CO poisoning?

EKG, serum CPK, LDH, psychometeric testing

Diagnostic Test Results-Diagnostic Procedures

Electrocardiography shows sinus tachycardia, arrhythmias due to hypoxia, and ischemia or infarction.

Nursing Considerations-Nursing Interventions

Ensure immediate removal of the patient from the source of CO. Administer 100% oxygen via a tight-fitting nonrebreather mask. Continue therapy until the patient is asymptomatic and carboxyhemoglobin levels fall below 10%. Assist with endotracheal intubation and mechanical ventilation as appropriate. Prepare the patient for hyperbaric oxygen therapy, as appropriate. Institute continuous cardiac monitoring to evaluate for changes and development of arrhythmias. Assess level of consciousness and neurologic status. Reorient the patient as necessary. Help the patient use positive coping strategies. Offer support and encourage the patient to express his feelings. Answer questions honestly. Provide consistent, clear explanations. If exposure was intentional, arrange for counseling and institute a no-self-harm contract. Obtain specimens for laboratory testing, such as ABG analysis, electrolyte levels, and carboxyhemoglobin levels.

What symptoms will be seen in COHb of >80%?

Fatal

Fetal pathogenesis of CO

Fetal Hb binds more avidly than HbA Fetal levels decrease more slowly Brain lipid peroxidation - correlate with neurological deterioration

What symptoms will be seen in COHb of <10%.

Mild headache, dyspnea on vigorous exertion No physical findings

Overview-Complications

Myocardial infarction Heart failure Pulmonary edema Aspiration pneumonia Encephalopathy Memory impairment Intellectual dysfunction Shock

What symptoms will be seen in COHb of 20-40%?

Nausea, dizziness, irritability, fatigue, severe headache, confusion, decreased visual acuity, dyspnea on moderate exertion

hyperbaric oxygen chamber

O2 pressure is increased 2-3 times the amount of atmospheric O2

What should the disposition be of a CO poisoning patient?

Patients with COHb levels >25% need to be admitted, close observation or hospital admission until COHb level is <5%

where is CO rapidly absorbed

pulmonary endothelium

What is delayed neuropsychiatric syndrome?

3-240 days after exposure will have memory loss, personality changes, parkinsonsim, mutism, No clinical or laboratory predictors

half life of CO

300 minutes on room air 90 min w high flow oxygen 30 min in hyperbaric chamber

hyperbaric oxygen tx indications

>25% CO >25% CO in preggos (bc CO has an even greater affinity for fetal Hb) severe metabolic acidosis LOC end organ ischemia (via ECG)

What are the different types of CO Poisoning.

Acute CO poisoning - single exposure, medical attention Chronic CO - more than 1 exposure, low concentrations Occult CO Poisoning - never seek medical attention

Symptoms of CO poisoning.

Acute exposure symptoms may not correlate with COHb levels With acute and chronic exposures, any chronic problems will exacerbate, even at low COHb levels Chest pain MI

What is important to understand if the CO poisoning was a suicide attempt?

Also look for Acetaminophen, ASA, ethanol overdose as well.

Nursing Considerations-Associated Nursing Procedures

Arterial puncture for blood gas analysis Blood pressure assessment Carbon monoxide oximetry Cardiac monitoring Cardiac output measurement with iced injectate IV bag preparation IV bolus injection IV catheter insertion Intubation with direct visualization Mechanical ventilation, positive pressure Neurologic assessment Oxygen administration Protective environment (PE) guidelines Pulmonary artery pressure and pulmonary artery wedge pressure monitoring Pulse assessment Pulse oximetry Respiration assessment 12-lead electrocardiogram (ECG) Urine glucose and ketone tests Urine specimen collection, random Venipuncture

Treatment-Activity

Bed rest during the acute phase As tolerated as condition improves

Overview-Incidence

CO poisoning can affect any age-group. It's responsible for 5,000 to 6,000 deaths annually. Approximately 500 of these deaths are unintentional; the remaining deaths are intentional.

Carbon monoxide.

Carbon monoxide is a colorless, odorless, tasteless, nonirritating gas. When inhaled it produces toxicity by causing cellular hypoxia.

Diagnostic Test Results-Imaging

Chest X-rays are usually normal. Head computed tomography scanning may be used to identify neurologic complications.

What are the s/s of CO poisoning?

Classic cherry red skin and bright red venous blood are infrequent and late findings.

Overview-Risk Factors

Confinement in a closed space with an improperly functioning heater, stove, or running engine Cigarette smoking Occupation involving coal mining, auto repair, paint removal, or solvent use Improper or inadequate venting of devices, such as kerosene heaters, camping stoves, gas-powered generators, and charcoal grills

How do you diagnose CO poisoning?

History: most reliable indicator - all victims at a fire scene must be evaluated for CO poisoning COHb - levels may be low because of time elapsed between exposure and presentation to the ED Need to rule out thermal injury or other gas inhalation

What is the treatment for CO poisoning?

Hyperbaric Oxygen Therapy HBO produces more rapid reduction in COHb levels Decreased COHb levels in 23 minutes at 3 atmospheres Induces cerebral vasoconstriction Consider in individuals with severe intoxication, do not respond rapidly to oxygen at room air, pregnant women with COHb >15%, Newborns

Nursing Considerations-Nursing Diagnoses

Impaired gas exchange Ineffective coping Ineffective peripheral tissue perfusion Risk for ineffective cardiac perfusion Risk for ineffective cerebral tissue perfusion Risk for injury

Overview-Causes

Inhalation (intentional or unintentional)

Overview

Inhalation of dangerous amounts of carbon monoxide (CO), a colorless, odorless, tasteless gas that usually results from the combustion of carbon-containing materials Can be unintentional or intentional (as with suicide) Also results from inhalation of methylene chloride vapors, a chemical found in industrial chemicals and solvents (paint thinners and removers); converted in the liver to carbon monoxide through dermal absorption, inhalation, or ingestion

Assessment-History

Malaise Dyspnea on exertion Lethargy Nausea Vomiting Abdominal pain Headache (most common) Drowsiness Dizziness

What is the prognosis of CO Poisoning?

Neurologic recovery with moderate CO poisoning is good 10% severe intoxication will develop a syndrome of neurologic deterioration Higher risk >40 years, prolonged exposure, CT/MRI abnormalities

Patient Teaching-Discharge Planning

Refer the patient and family to local support services, as necessary, to assist with financial concerns. Refer the patient for professional counseling or mental health care, as appropriate, if exposure was intentional.

Treatment-General

Removal from source of CO Supportive care Respiratory support, including endotracheal intubation and mechanical ventilation if indicated

What are sources of carbon monoxide poisoning?

Sterno fuel Tobacco smoke Vehicular smoke exhausts Water heaters Wood stoves

Assessment-Physical Findings

Tachycardia Hypotension or hypertension Hyperthermia Cherry-red lips (not a reliable indicator) and skin or pallor Impaired judgment Papilledema; bright red retinal veins; flame-shaped retinal hemorrhages Ataxia Seizures Emotional lability Brisk reflexes Coma Arrhythmias

What symptoms will be seen in COHb of 41-70%?

Tachycardia, tachypnea, lethargic, ataxia, syncope, seizures, myocardial ischemia, pulmonary edema, metabolic acidosis, coma

Overview-Pathophysiology

The lungs rapidly absorb CO after inhalation. CO is rapidly diffused across the alveoli and picked up on hemoglobin. CO has a high affinity for hemoglobin, reversibly binding with hemoglobin and resulting in the formation of carboxyhemoglobin. Subsequently, oxygenation is impaired and the oxygen-hemoglobin dissociation curve shifts to the left, leading to tissue hypoxia. CO binds to cardiac myoglobin resulting in cardiac depression and hypotension also contributing to further tissue hypoxia. CO also rapidly binds to cytochrome C oxidase in the cell, causing toxicity to the mitochondria, inhibiting cellular respiration, and impairing mitochondrial and muscle function.

Nursing Considerations-Monitoring

Vital signs Cardiopulmonary status Hemodynamics Oxygenation Neurologic function Coping strategies Suicidal ideation ABG results

how does carboxyhemoglobin result in decreased oxygen transport and tissue ischemia

binds to cytochrome oxidase and impairs mitochondrial function

how does carboxyhemoglobin affect muscle function

binds to myoglobin

why is pulse oximetry not reliable

cannot differentiate between carboxyhemoglobin and oxyhemoglobin

late sign of CO poisoning

cherry red skin

2 factors CO elimination is dependent on

degree of oxygenation minute ventilation

DNS

delayed neuropsychiatric syndrome symptom of CO poisoning arises days/weeks/months after CO poisoning recovery characterized by personality changes, movt disorders, neurological defects

Patient Teaching-General

disorder, diagnosis, and treatment the fact that recovery usually occurs in 4 to 8 weeks and that recurrence is very low possibility of delayed neurologic complications need to reduce physical activity for approximately 2 to 4 weeks importance of smoking cessation importance of adequate ventilation, especially when using fuel-burning devices or working with solvents or paint removers positive coping strategies use of home CO monitors importance of maintaining regular follow-up care with a practitioner to monitor for resolution of the condition importance of follow-up care for counseling as appropriate (if toxicity was intentional) need for serial echocardiography to evaluate for improved function.

methylene chloride

inhaled/ingested and then converted to CO by the liver

Nursing Considerations-Expected Outcomes

maintain adequate ventilation and oxygenation identify positive coping strategies exhibit adequate peripheral tissue perfusion maintain adequate cardiac output and hemodynamic stability maintain adequate cerebral tissue perfusion remain free from injury and complications.

why order a head CT?

to rule out other causes of neurologic deficits