Symptoma

Carbon Monoxide Poisoning

Carbon Monoxide Poisonings

Carbon monoxide poisoning is a potentially fatal condition caused by inhalation of carbon monoxide, a toxic, colorless, odorless and tasteless gas.

The symptoms are acute and develop rapidly. Unborn fetuses, neonates and young children are more susceptible to harmful effects of carbon monoxide [5]. These include:

Chronic poisoning due to exposure to low concentrations of carbon monoxide is also common. It is seen in cases of occupational exposure to carbon monoxide or in smokers. Even chronic passive smoking can cause these symptoms. The signs of chronic exposure usually disappear on spending time away from workplace or home and may give an indication of carbon monoxide poisoning. The signs and symptoms of chronic poisoning include:

In people with heart problems, respiratory disorders, and anemia and in pregnant women, even minor exposure to carbon monoxide may prove to be fatal. Encephalopathies develop in neonates as a result of carbon monoxide exposure.

  • Fatigue

    Symptoms include headache, fatigue, dizziness, nausea or vomiting, and loss of consciousness. [web.archive.org]

    Soon after, rescuers complained of dizziness and developed headache, nausea and fatigue. A carbon monoxide level of 600 ppm was detected. Three rescuers were treated with 100% oxygen. [ncbi.nlm.nih.gov]

    A 39-year-old female executive has a several-month history of fatigue, headache, and memory lapse. During a period of feeling worse than usual, she called a friend, who arrived at the residence to find the woman semicomatose and called 911. [doi.org]

  • Anemia

    Infants, the elderly, people with chronic heart disease, anemia, or breathing problems are more likely to get sick from CO. [web.archive.org]

    The most at-risk groups are unborn babies, infants, people living at high altitudes, those with chronic heart disease, anemia or respiratory problems, and people with already-elevated CO levels such as smokers. [my.clevelandclinic.org]

    Infants, pregnant women, people with lung or heart disease, and people with anemia are especially vulnerable to the effects of carbon monoxide poisoning. [health.ri.gov]

    Fetuses Infants Elderly People Those who suffer from anemia, respiratory or heart disease Precautionary Measures Routinely at the beginning of every heating season home owners should have their fuel burning appliances checked by a qualified technician [carbon-monoxide-poisoning.com]

  • Fever

    Mild carbon monoxide poisoning may present as viral symptoms in the absence of fever. While headache, nausea, and vomiting are the most common presenting symptoms in children, the most common symptom in infants is consciousness disturbance. [ncbi.nlm.nih.gov]

    However, the flu often comes with a fever. As carbon monoxide poisoning progresses, more severe symptoms may include fainting, difficulty thinking clearly, increased heart rate, and eventually loss of consciousness and convulsions. [cbsnews.com]

    The initial symptoms of low to moderate CO poisoning are similar to the flu (but without the fever). [cpsc.gov]

    However, unlike the flu, carbon monoxide poisoning does not cause a high temperature (fever). [wwutilities.co.uk]

    Initial symptoms are similar to the flu but without the fever, headache, fatigue shortness of breath nausea dizziness skin may turn bright red. [al.com]

  • Malaise

    The signs and symptoms of chronic poisoning include: Frequent headache Nausea and vomiting Amnesia Tachypnea Malaise Dyspnea on exertion Confusion Depression Behavioral changes In people with heart problems, respiratory disorders, and anemia and in pregnant [symptoma.com]

    Acute poisoning Malaise, flulike symptoms, fatigue Dyspnea on exertion Chest pain, palpitations Lethargy Confusion Depression Impulsiveness Distractibility Hallucination, confabulation Agitation Nausea, vomiting, diarrhea Abdominal pain Headache, drowsiness [web.archive.org]

    The initial symptoms of acute carbon monoxide poisoning include headache, nausea, malaise, and fatigue. These symptoms are often mistaken for a virus such as influenza or other illnesses such as food poisoning or gastroenteritis. [en.wikipedia.org]

    […] exposure to carbon monoxide (elevation of the carboxyhemoglobin level or the ambient carbon monoxide concentration) or an obvious exposure to carbon monoxide and if they had any of the following symptoms: loss of consciousness, confusion, headache, malaise [doi.org]

    [11] However, any of the following symptoms should alert suspicion in the winter months, especially when the patient has a history compatible with CO exposure and when more than one patient in a group or household presents with similar complaints: Malaise [emedicine.medscape.com]

  • Hypothermia

    We present a preliminary case report series of severe, acute carbon monoxide poisoning in which both hyperbaric oxygen (HBO2) and therapeutic hypothermia (TH) were used to ameliorate neurological sequelae. [ncbi.nlm.nih.gov]

    Suggested related reading from Medictests.com The Quick and Dirty Guide to Hypothermia The Quick and Dirty Guide to Difficulty Breathing The Quick and Dirty Guide to Acid Base Balance Other links for further study Really Good Video Breakdown of Dyshemoglobinemia [medictests.com]

    Hypothermia — Development of a subnormal body temperature. pH — A measurement of the acidity or alkalinity of a fluid. [medical-dictionary.thefreedictionary.com]

  • Dyspnea

    Patient experienced ecphysesis and dyspnea suddenly after HBO₂ therapy (100% oxygen at 0.25 MPa, for 60 minutes with a five-minute air break and decompression at 0.01 MPa/minute). [ncbi.nlm.nih.gov]

    Carbon monoxide (CO) poisoning causes acute symptoms such as headache, nausea, weakness, angina, dyspnea, loss of consciousness, seizures, and coma. Neuropsychiatric symptoms may develop weeks later. [merckmanuals.com]

  • Tachypnea

    Abnormal physical findings included tachypnea in 79% and tachycardia in 47%. The mean COHb value was 26.3 /-11.5%. Syncope occurred more frequently in patients with high COHb levels (P 0.001) and was more common among females (P 0.003). [ncbi.nlm.nih.gov]

    Abnormal physical findings included tachypnea in 79% and tachycardia in 47%. The mean COHb value was 26.3 11.5%. Syncope occurred more frequently in patients with high COHb levels ( P P 0.003). [doi.org]

    The signs and symptoms of chronic poisoning include: Frequent headache Nausea and vomiting Amnesia Tachypnea Malaise Dyspnea on exertion Confusion Depression Behavioral changes In people with heart problems, respiratory disorders, and anemia and in pregnant [symptoma.com]

    Vital signs Tachycardia Hypertension or hypotension Hyperthermia Marked tachypnea (rare; severe intoxication often associated with mild or no tachypnea) Skin: Classic cherry red skin is rare (ie, "When you're cherry red, you're dead"); pallor is present [web.archive.org]

    CVS: Dysrhythmias, Ischaemia, hyper or hypotension (exacerbated in patients with anaemia or underlying cardiovascular disease) GI: abdominal pain, N V, diarrhoea RESP: dyspnea, tachypnea, chest pain, palpitation Other: Non-cardiogenic pulmonary oedema [lifeinthefastlane.com]

  • Hyperpnea

    FULL TEXT Isocapnic Hyperpnea Accelerates Carbon Monoxide Elimination FISHER et al. Am. J. Respir. Crit. Care Med. 1999;159:1289-1292. ABSTRACT FULL TEXT Carbon Monoxide Poisoning Ernst and Zibrak NEJM 1998;339:1603-1608. [web.archive.org]

    Isocapnic hyperpnea accelerates carbon monoxide elimination. American journal of respiratory and critical care medicine. 159(4 Pt 1):1289-92. 1999. [ pubmed ] Henry CR, Satran D, Lindgren B, Adkinson C, Nicholson CI, Henry TD. [lifeinthefastlane.com]

    Fisher and colleagues ( 100, 101 ) have recently developed a method for normocapnic hyperpnea that allows for an increase in minute ventilation, and thus increased clearance of COHb, without harmful hypercapnia. [doi.org]

  • Nausea

    Secondary end points included nausea, need for rescue medication during treatment, and reduction in carboxyhemoglobin levels. [ncbi.nlm.nih.gov]

  • Vomiting

    While headache, nausea, and vomiting are the most common presenting symptoms in children, the most common symptom in infants is consciousness disturbance. [ncbi.nlm.nih.gov]

    Symptoms include headache, fatigue, dizziness, nausea or vomiting, and loss of consciousness. [web.archive.org]

    It hinders the oxygen supply to the body tissues, posing fatal health problems like difficulty in breathing, dizziness, double vision, lightheadedness, abdominal pain, nausea and vomiting. [symptoma.com]

  • Diarrhea

    CASE REPORT: A 53-year-old woman presented to our ED, reporting non-specific but common symptoms including emesis and diarrhea, one-sided headache, paresthesia, and palpitations. [ncbi.nlm.nih.gov]

    Diseases and Disorders section features more than 300 new figures and tables, as well as 20 new topics including: cyclic vomiting syndrome, traveler’s diarrhea, chronic pruritus, post-herpetic neuralgia, enteropathic arthritis, and hoarding disorder. [books.google.com]

    Acute poisoning Malaise, flulike symptoms, fatigue Dyspnea on exertion Chest pain, palpitations Lethargy Confusion Depression Impulsiveness Distractibility Hallucination, confabulation Agitation Nausea, vomiting, diarrhea Abdominal pain Headache, drowsiness [web.archive.org]

    […] group or household presents with similar complaints: Malaise, flulike symptoms, fatigue Dyspnea on exertion Chest pain, palpitations Lethargy Confusion Depression Impulsiveness Distractibility Hallucination, confabulation Agitation Nausea, vomiting, diarrhea [emedicine.medscape.com]

    More unique symptoms of chronic CO exposure include chronic fatigue, vertigo, paraesthesias, polycythemia, abdominal pain, diarrhea, and recurrent infections ( 29, 42 ). [doi.org]

  • Chest Pain

    A 47-year-old female patient complained of sudden chest pain for 30 minutes. Before admission, the patient had non-radiating burning chest pain after inhalation of soot. [ncbi.nlm.nih.gov]

    Levels 30% commonly cause dyspnea during exertion, chest pain (in patients with coronary artery disease), and confusion. Higher levels can cause syncope, seizures, and obtundation. [merckmanuals.com]

    Shortly thereafter, Anita — who has had two heart attacks — said she began experiencing chest pain. She took nitroglycerin and her conditions temporarily improved. As she went upstairs, the chest pain returned and Anita took a second nitroglycerin. [thegazette.com]

  • Hypotension

    Initial signs included respiratory failure, cardiac ischaemia, hypotension, encephalopathy and a rash, whilst subsequent features included rhabdomyolysis, renal failure, amnesia, dysarthria, parkinsonism, peripheral neuropathy, supranuclear gaze palsy [ncbi.nlm.nih.gov]

    Paramedics had been called and found him to be pyrexial, hypotensive, tachypnoeic and tachycardic. His Glasgow Coma Score (GCS) was 7. He had been doubly incontinent. His chest was clear. [doi.org]

    Hypotension occurs. Carbon monoxide also affects the mitochondrial oxidation. It binds to cytochrome oxidase, an enzyme required for normal oxidative process, thereby affecting the energy processes. Cytochrome C and P450 are also affected. [symptoma.com]

  • Tachycardia

    To the best of our knowledge, this case report is the first carbon monoxide intoxication case in the literature presenting with supraventricular tachycardia attack. [Indexed for MEDLINE] Free full text [ncbi.nlm.nih.gov]

    Abnormal physical findings included tachypnea in 79% and tachycardia in 47%. The mean COHb value was 26.3 11.5%. Syncope occurred more frequently in patients with high COHb levels ( P P 0.003). [doi.org]

  • Cyanosis

    In spite of asphyxiation, cyanosis (turning blue) does not occur; the skin is pink or pale and the lips bright red. [britannica.com]

    Liver function tests - Mild elevation in fulminant hepatic failure Urinalysis - Positive for albumin and glucose in chronic intoxication Methemoglobin level - Included in the differential diagnosis of cyanosis with low oxygen saturation but normal PaO [emedicine.medscape.com]

  • Retrosternal Chest Pain

    A 36-year-old man with retrosternal chest pain was admitted after exposure to CO. The initial electrocardiogram (ECG) showed ST depression in I, aVL, and V3-V4 with slight ST elevation in II, III, aVF leads. [ncbi.nlm.nih.gov]

  • Flushing

    Nicholas Wilkinson thought it had been cause by a ‘flushed kittie’ (a blown out shot), which blew down the stopping and blew the gas into the men's lamps. The Inspectors, Mr. Bell and Mr. [healeyhero.co.uk]

    This is apparently something which cannot be overridden and may prevent hemodialysis from occurring until the hydroxocobalamin has been sufficiently flushed from the system. 29 CARBON MONOXIDE CO works by many of the same pathways as CN but has a different [doi.org]

  • Tinnitus

    Difficulty in thinking 46 (44%) 37 (43%) Dizziness 38 (37%) 21 (24%) Nausea 38 (37%) 25 (29%) Acute confusional state 20 (19%) 10 (11%) Paraesthesiae 11 (11%) 6 (7%) Visual disturbance 9 (9%) 4 (5%) Palpitations 8 (8%) 3 (3%) Chest pain 7 (7%) 3 (3%) Tinnitus [web.archive.org]

  • Benign Paroxysmal Positional Vertigo

    The patient described vague, non-specific symptoms not consistent with a diagnosis of benign paroxysmal positional vertigo, labyrinthitis or Ménière's disease. [ncbi.nlm.nih.gov]

  • Retinal Hemorrhage

    Ophthalmologic Flame-shaped retinal hemorrhages Bright red retinal veins (a sensitive early sign) Papilledema Homonymous hemianopsia Noncardiogenic pulmonary edema Neurologic and/or neuropsychiatric Patients display memory disturbance (most common), including [web.archive.org]

    hemorrhages Bright red retinal veins (a sensitive early sign) Papilledema Homonymous hemianopsia Noncardiogenic pulmonary edema Neurologic and/or neuropsychiatric findings may include the following; Memory disturbance (most common), including retrograde [emedicine.medscape.com]

  • Blurred Vision

    The most indicative symptoms experienced were a severe headache, blurred vision, agitation, and confusion. [ncbi.nlm.nih.gov]

    It can also cause sleepiness, blurred vision, ringing in the ears, breathing problems, and confusion. Because CO poisoning is more common in the colder months when colds and flu are common, you might mistake CO poisoning for a cold or flu. [healthvermont.gov]

  • Diplopia

    These include: Dizziness Confusion Agitation Delirium and hallucinations Headache Vertigo Visual disturbances like diplopia Abdominal pain Lethargy Chest pain Palpitation Difficulty in breathing Convulsions Paralysis Syncope Ultimately, death Chronic [symptoma.com]

  • Psychiatric Manifestation

    The most significant neurologic and psychiatric manifestations of carbon monoxide poisoning are subacute or late sequelae, often following a period of complete recovery from an acute episode. [medlink.com]

  • Headache

    To evaluate systematically the characteristics of headache due to acute exposure to carbon monoxide. Headache is the most commonly reported symptom in acute carbon monoxide poisoning. [ncbi.nlm.nih.gov]

    —The headache accompanying acute carbon monoxide poisoning is extremely variable in nature. “Classic” throbbing, diffuse headaches were rarely described by patients. [doi.org]

  • Dizziness

    We report an unusual case of dizziness caused by carbon monoxide poisoning. A 55-year-old man was referred to an ENT surgeon with dizziness. [ncbi.nlm.nih.gov]

    […] and nausea 800 2 hours Collapse and possible unconsciousness 1600 20 minutes Headache, dizziness and nausea 1600 2 hours Collapse, unconsciousness, possible death 3200 5-10 minutes Headache and dizziness 3200 10-15 minutes Unconsciousness and possible [carbonmonoxide.ie]

  • Confusion

    This is the biggest headache for the physician, and it is an area where confusion is common. [doi.org]

    We present an acutely confused adolescent patient who had CO poisoning after narghile tobacco smoking. She presented with syncope and a carboxyhemoglobin level of 24% and was treated with hyperbaric oxygen. [ncbi.nlm.nih.gov]

  • Seizure

    Various reports show the occurrence of self-limiting seizures after carbon monoxide poisoning and as a consequence of hyperbaric oxygen therapy. Contrary to the seizures, status epilepticus has been rarely observed in these conditions. [ncbi.nlm.nih.gov]

    Seizures occurred significantly more often in patients with a COHb level of 20%. CO exposure in our patients was acute, accidental, and occurred during the winter months. [doi.org]

    Carbon monoxide (CO) poisoning causes acute symptoms such as headache, nausea, weakness, angina, dyspnea, loss of consciousness, seizures, and coma. Neuropsychiatric symptoms may develop weeks later. [merckmanuals.com]

    Progressive Symptoms of Carbon Monoxide Poisoning Headache Dizziness Irritability Confusion/Memory Loss Nausea and Vomiting Abnormal Reflexes Difficulty in coordination Difficulty in breathing Chest pain Cerebral edema Convulsions/Seizures Coma Death [medictests.com]

  • Irritability

    The specific neurological sequelae included headaches, irritability, personality changes, confusion, and loss of memory. [ncbi.nlm.nih.gov]

    It does not irritate the eyes or respiratory tract. When a person inhales carbon monoxide, the gas enters their blood and interferes with oxygen intake. This damages tissue and can be extremely dangerous to health. [quebec.ca]

    CO exposure range from subtle neuropsychologic signs and symptoms to coma and death and can include headache, dizziness, fatigue, weakness, drowsiness, nausea, vomiting, loss of consciousness, skin pallor, dyspnea on exertion, palpitation, confusion, irritability [cdc.gov]

    Early symptoms of carbon monoxide poisoning include irritated eyes, headache and dizziness. These should not be confused with the flu, seasickness or intoxication. [rms.nsw.gov.au]

  • History of the patient is important is formulation of diagnosis. Occupational or domestic exposure to carbon monoxide can be confirmed.
  • Physical examination, especially of vitals, can give an idea of chronic carbon monoxide poisoning.
  • Determination of carboxyhemoglobin levels in the body is helpful. It is usually raised in carbon monoxide poisoning; however, low levels do not rule out the diagnosis.
  • Creatine Kinase-MB fraction levels are evaluated to detect any myocardial ischemia resulting from carbon monoxide poisoning.
  • Electrolytes and glucose levels are required to rule out other causes of mental derangement.
  • Blood urea nitrogen (BUN) and creatinine levels
    Liver function tests (LFTs) may be needed to assess liver damage.
  • Urinalysis should also be done.
  • Chest X-ray for pulmonary findings
  • Computerized tomography (CT) & magnetic resonance imaging (MRI) of the head are also taken to rule out other neurologic causes. [6][7]
  • Electrocardiography (ECG) often demonstrates sinus tachycardia. Other types of arrhythmias may also be seen.
  • Hypercapnia

    Fisher and colleagues ( 100, 101 ) have recently developed a method for normocapnic hyperpnea that allows for an increase in minute ventilation, and thus increased clearance of COHb, without harmful hypercapnia. [doi.org]

  • Ischemic Changes

    Carbon monoxide (CO) is one of the leading causes of poisoning; it inhibits oxygen delivery, subsequently causing ischemic changes and ultimately death by multiorgan failure. [ncbi.nlm.nih.gov]

    This evaluation may be confounded by several factors, including the absence of overt symptoms and of specific ischemic changes in the electrocardiogram. [doi.org]

Immediate care should be given to the patients [8].

The prognosis of carbon monoxide poisoning is hard to predict. About 30% of the patients suffer fatal complications due to unavailability of immediate medical care. About 11% of the surviving patients suffer from chronic neurological disorders particularly, memory loss. Longer the exposure to carbon monoxide, poorer is the prognosis. Delay in treatment can also lead to poor outcomes.

Carbon monoxide poisoning is usually accidental and caused by [2] [3]:

  • Incomplete burning of gasoline, petrol, diesel or coal in industrial furnaces
  • Carbon monoxide leakage from automobile exhausts
  • Burning of gasoline or coal heaters or stoves at home without proper ventilation
  • Faulty breathing apparatus in scuba divers and mountaineers
  • Gas pipes leakage
  • Blocked chimneys or gas vents
  • Running automobiles in closed garages
  • Indoor grilling
  • Gasoline run generators
  • Wood burning stoves
  • Smoke inhalation
  • Chronic smoking

Exact number of accidents and deaths due to carbon monoxide poisoning is unknown and majority of the cases go unregistered. No racial factors are involved. Males are, however, more predisposed to carbon monoxide poisoning due to workplace exposure.

The cases of carbon monoxide poisoning have a seasonal tendency due to use of heaters and burning of wood and coal for keeping warm in the winters.

Once inhaled, carbon monoxide rapidly diffuses across the alveolar membrane and passes into the blood stream to bind to hemoglobin after displacing oxygen. Another oxygen carrying protein, myoglobin, is also bound by carbon monoxide.

Carboxyhemoglobin (HbCO) is formed as a result. Carboxyhemoglobin not only limits the oxygen delivery to the tissues but also decreases the affinity of hemoglobin for normal oxygen [4]. The tissues suffer hypoxic injury as a result of tissue asphyxia. Cardiac output is reduced. Hypotension occurs.
Carbon monoxide also affects the mitochondrial oxidation. It binds to cytochrome oxidase, an enzyme required for normal oxidative process, thereby affecting the energy processes. Cytochrome C and P450 are also affected. Acidosis occurring as a result of carboxyhemoglobin formation leads to hyperventilation and shortness of breath.

Carbon monoxide also causes the release of nitric oxide (NO) from vascular epithelium, leading to vasodilation, leakage of plasma from capillaries and edema. Oxygen free radicals trigger the apoptotic pathway, causing irreversible cell injury if the condition persists for long. In the central nervous system (CNS), demyelination of nerve fibers is interfered with. In brain tissue, areas of necrosis might be seen.

  • Gas pipes should be regularly checked for leakage.
  • Proper ventilation of the spaces where heaters or stoves are burnt should be ensured.
  • Heaters should be turned off before sleeping.
  • Professionals should be employed for installation of gas operated and other heating appliances.
  • Carbon monoxide detectors should be installed in industrial and domestic setups.

Carbon monoxide (CO) is the gas produced as a result of incomplete oxidation process. It is commonly produced as a by-product during industrial or domestic burning of gasoline, diesel or petrol or coal. The gas is colorless, odorless (therefore, difficult to detect) and has high affinity for hemoglobin in human blood. It is, therefore, aptly known as the “silent killer”. It readily enters the circulation, displacing oxygen from the hemoglobin and depriving the tissues of oxygen. Rapid treatment is usually required in cases of carbon monoxide poisoning to counter its effects [1].

Improper burning of wood, gas or petrol can cause the formation of carbon monoxide gas which is highly toxic to the human body. It hinders the oxygen supply to the body tissues, posing fatal health problems like difficulty in breathing, dizziness, double vision, lightheadedness, abdominal pain, nausea and vomiting. The person can faint and even go into a coma if not treated immediately.

The gas operated stoves and heaters should be checked regularly to avoid leakage problems. Areas where stoves are burnt should be well ventilated. With proper precautionary measures, carbon monoxide poisoning can be avoided.

  1. Varon J, Marik PE, Fromm RE, Jr., Gueler A. Carbon monoxide poisoning: a review for clinicians. The Journal of emergency medicine. Jan-Feb 1999;17(1):87-93.
  2. Simpson K. The danger of accidental carbon monoxide poisoning; a review of 100 cases. British medical journal. Oct 2 1954;2(4891):774-776.
  3. Mant AK. Accidental carbon monoxide poisoning: a review of 100 consecutive cases. The Medico-legal journal. 1960;28:30-39.
  4. Thom SR, Keim LW. Carbon monoxide poisoning: a review epidemiology, pathophysiology, clinical findings, and treatment options including hyperbaric oxygen therapy. Journal of toxicology. Clinical toxicology. 1989;27(3):141-156.
  5. Yarar C, Yakut A, Akin A, Yildiz B, Dinleyici EC. Analysis of the features of acute carbon monoxide poisoning and hyperbaric oxygen therapy in children. The Turkish journal of pediatrics. May-Jun 2008;50(3):235-241.
  6. Beppu T. The role of MR imaging in assessment of brain damage from carbon monoxide poisoning: a review of the literature. AJNR. American journal of neuroradiology. Apr 2014;35(4):625-631.
  7. Ferrier D, Wallace CJ, Fletcher WA, Fong TC. Magnetic resonance features in carbon monoxide poisoning. Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologistes. Dec 1994;45(6):466-468.
  8. Crocker PJ. Carbon monoxide poisoning, the clinical entity and its treatment: a review. Military medicine. May 1984;149(5):257-259.
  9. Norkool DM, Kirkpatrick JN. Treatment of acute carbon monoxide poisoning with hyperbaric oxygen: a review of 115 cases. Annals of emergency medicine. Dec 1985;14(12):1168-1171.
  10. Di Mauro G, Marchesi G, Longoni C, Pani U. [Treatment of acute carbon monoxide poisoning with hyperbaric oxygen therapy: review of the last 2 years' experience]. Minerva anestesiologica. Oct 1991;57(10):968-969.

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