1/39. Apneustic breathing in children with brainstem damage due to hypoxic-ischemic encephalopathy.To confirm the presence of apneusis in patients with hypoxic-ischemic encephalopathy and to clarify which factors influence their respiratory patterns, polygraphic studies were performed on two patients. Apneusis was clinically suspected in both patients who had severe brainstem damage. In one subject, inputs of vagal afferents from the gastrointestinal tract and the urinary bladder often resulted in extreme tachypnea instead of apneusis. lung inflation facilitated expiration during inspiratory arrest. Expiration preceded a periodic inhibition of rigospastic discharge in the right biceps muscle. In the other subject, prolonged inspiratory pauses with cyanosis occurred with or without preceding epileptic seizure. Both phenytoin dose reduction and treatment with tandospirone, a serotonin-1A agonist, were effective in improving the respiratory distress in this subject.- - - - - - - - - - ranking = 1keywords = gas (Clic here for more details about this article) |
2/39. pressure limited ventilation with permissive hypoxia and nitric oxide in the treatment of adult respiratory distress syndrome.In the management of adult respiratory distress syndrome pressure limited mechanical ventilation may protect the lungs from overdistention injury. Unacceptable hypoxia may be avoided by adding nitric oxide to the inspiratory gas, and thus make pressure limited ventilation easier to perform. There exists no consensus about an acceptable lower limit of SaO2, and in the present case we gave preference to pressure limitation at the cost of oxygenation. A young woman with severe adult respiratory distress syndrome was set on pressure limited mechanical ventilation with peak pressures of 35-38 cm H2O, PEEP of 10-12 cm H2O, and FiO2 of 0.95 with 20 ppm nitric oxide. SaO2 varied between 75 and 85%, and cardiac output ranged between 5.2 and 7.5 L min-1. oxygen consumption was in the upper normal range, and she did not became acidotic. After 3 days, she started to improve. In conclusion, it seems that hypoxia might be well tolerated as long as the circulation is not compromised. It might prove beneficial to accept some hypoxia to avoid ventilator induced lung damage.- - - - - - - - - - ranking = 1keywords = gas (Clic here for more details about this article) |
3/39. Transient swallow syncope during periods of hypoxia in a 67-year-old patient after self-extubation.OBJECTIVE: To describe the case of an adult patient with swallow syncope after bypass surgery, possibly related to hypoxia. DESIGN: Case report. SETTING: University hospital, medical-cardiologic intensive care unit. PATIENT: A 67-yr-old patient after second aortocoronary bypass operation for unstable angina. MAIN RESULTS: After the patient managed to extubate himself, he was in a borderline respiratory condition with an oxygen mask. When drinking for the first time after extubation, asystole was observed coincidentally with interruption of oxygen insufflation. During the next days, similar events occurred during food ingestion or when drinking liquids after a fall of oxygen saturation. The bradyarrhythmia was readily reversible on administration of atropine and ventricular backup pacing via temporary pacing wires. After normalization of gas exchange, no more episodes of swallowing-associated asystole were observed and the patient was discharged without a permanent pacemaker. There was no esophageal or gastrointestinal disease. Pre- and postoperative PR and QRS durations were normal. CONCLUSION: Extrinsic and transient mechanisms, rather than intrinsic conduction system disease, seem to have been operative in this case. It is suggested that hypoxia reinforced the vagal pharyngocardiac reflex as described in pediatric patients.- - - - - - - - - - ranking = 2keywords = gas (Clic here for more details about this article) |
4/39. nitrogen purging of oxygen pipelines: an unusual cause of intraoperative hypoxia.Intraoperative hypoxia occurred in two patients during the maintenance of the medical gas system. Engineers were purging oxygen pipelines with nitrogen to remove particulate debris but were unaware of a connection to operating room pipelines. This case illustrates the importance of communication between anesthesia providers and engineers servicing the gas system.- - - - - - - - - - ranking = 2keywords = gas (Clic here for more details about this article) |
5/39. Delivery of an hypoxic gas mixture due to a defective rubber seal of a flowmeter control tube.The delivery of an hypoxic gas mixture to a patient during general anaesthesia is a rare event due to contemporary standards of monitoring, equipment design and alarm features. An incident is described where a split occurred in a rubber seal round the top of a flowmeter control tube. This resulted in a downstream oxygen leak and the delivery of an hypoxic gas mixture to the patient. The bobbin on the oxygen flowmeter did not accurately reflect the amount of oxygen being delivered. A paramagnetic oxygen analyser and a fuel cell oxygen electrode indicated that the inspired oxygen concentration was lower than intended. The anaesthetic machine was exchanged, and the operation continued uneventfully. The faulty anaesthetic machine subsequently passed a formal pressure test by the hospital engineers and also close examination of the flowmeter control valves. The importance of monitoring equipment and the interpretation of the information that they provide is emphasized.- - - - - - - - - - ranking = 6keywords = gas (Clic here for more details about this article) |
6/39. Mechanical ventilation during pregnancy using a helium-oxygen mixture in a patient with respiratory failure due to status asthmaticus.The authors present a 15-year-old with a second trimester intrauterine pregnancy who developed respiratory failure as the result of status asthmaticus and the development of the adult respiratory distress syndrome. Mechanical ventilation was provided with a combination of oxygen and helium to facilitate gas exchange and limit peak inflating pressures. The physiologic basis for helium's potential beneficial effects on gas exchange are reviewed. Previous reports concerning the use of helium during mechanical ventilation as well as the techniques of delivery are discussed.- - - - - - - - - - ranking = 2keywords = gas (Clic here for more details about this article) |
7/39. Mutations of von Hippel-Lindau tumor-suppressor gene and congenital polycythemia.The von Hippel-Lindau (pVHL) protein plays an important role in hypoxia sensing. It binds to the hydroxylated hypoxia-inducible factor 1 alpha (HIF-1 alpha) and serves as a recognition component of an E3-ubiquitin ligase complex. In hypoxia or secondary to a mutated VHL gene, the nondegraded HIF-1 alpha forms a heterodimer with HIF-beta and leads to increased transcription of hypoxia-inducible genes, including erythropoietin (EPO). The autosomal dominant cancer-predisposition von Hippel-Lindau (VHL) syndrome is due to inheritance of a single mutated allele of VHL. In contrast, we recently showed that homozygous germline 598C-->T VHL mutation leads to Chuvash polycythemia (CP). We subsequently found VHL mutations in three unrelated individuals unaffected with CP, one of whom was compound heterozygous for the 598C-->T mutation and another VHL mutation. We now report seven additional polycythemic patients with VHL mutations in both alleles. Two Danish siblings and another American boy were homozygous for the VHL 598C-->T mutation. Three unrelated white Americans were compound heterozygotes for 598C-->T and another VHL mutation, 562C-->G in two and 574C-->T in the third. Additionally, a Croatian boy was homozygous for a 571C-->G VHL mutation, the first example of homozygous VHL germline mutation causing polycythemia, other than the VHL 598C-->T mutation. We have not observed VHL syndrome-associated tumors in polycythemic subjects or their heterozygous relatives; however, this will need to be evaluated by longitudinal studies. Over all, we found that up to half of the consecutive patients with apparent congenital polycythemia and increased serum Epo we have examined have mutations of both VHL alleles. Those findings, along with reports of CP, underscore that VHL mutations are the most frequent cause of congenital polycythemia and define a new class of polycythemic disorder, polycythemias due to augmented hypoxia sensing.- - - - - - - - - - ranking = 1keywords = gas (Clic here for more details about this article) |
8/39. Unusual facial markings and lethal mechanisms in a series of gasoline inhalation deaths.A review of deaths associated with hydrocarbon toxicity from gasoline sniffing in south australia throughout a 10 year period from July 1987 to June 2002 revealed 4 cases. The victims were all Aboriginal people from remote inland communities. Each death had occurred while the victim was lying in bed sniffing gasoline from a can held to the face. Once unconsciousness had occurred, the mouth and nose had been pressed firmly against the can by the weight of the head. In each case, the effects of gasoline toxicity had been exacerbated by hypoxia and hypercapnia from rebreathing into the container once a tight seal had been established between the face and the can. The circular impressions left by the can edges on the faces of each of the victims provided an autopsy marker that assisted in clarifying the details of the fatal episodes. Discouraging solitary gasoline sniffing in bed may reduce the death rate in communities where this behavior is practiced.- - - - - - - - - - ranking = 8keywords = gas (Clic here for more details about this article) |
9/39. Death scene gas analysis in suspected methane asphyxia.Two cases of methane asphyxia occurring in two boys (age 11 and 12 years) who were found at the bottom of a 37-ft (11.1-m)-deep sewer shaft are described. Attempted resuscitation of the first patient was unsuccessful and achieved only temporary stabilization of the second, who died 48 h after his discovery. Autopsies revealed relatively minor multifocal traumatic injuries, with evidence of hypoxic-ischemic encephalopathy in the patient who survived for 2 days. Subsequent analysis of gas in the shaft revealed 21% oxygen at the surface, 14.3% at a depth of 5 ft (1.5 m), and only 4.8% at depths of 10 ft (3 m) and below. Other gases detected at the lower levels were methane, nitrogen, and carbon dioxide (4.3%). These cases demonstrate the value of atmospheric gas analysis in cases of possible methane asphyxia in confirming the presence of methane and in demonstrating levels of oxygen below that necessary to support life.- - - - - - - - - - ranking = 7keywords = gas (Clic here for more details about this article) |
10/39. Three cases of sudden death due to butane or propane gas inhalation: analysis of tissues for gas components.We report three cases of sudden death due to inhalation of portable cooking stove fuel (case 1), cigarette lighter fuel (case 2), and liquefied petroleum gas (LPG) (case 3). Specimens of blood, urine, stomach contents, brain, heart, lung, liver, kidney, and fat were collected and analyzed for propylene, propane, isobutane, and n-butane by headspace gas chromatography. n-Butane was the major substance among the volatiles found in the tissues of cases 1 and 2, and propane was the major substance in case 3. A combination of the autopsy findings and the gas analysis results revealed that the cause of death was ventricular fibrillation induced by hard muscle exercise after gas inhalation in cases 1 and 2, and that the cause of death in case 3 might be hypoxia. It is possible that the victim in case 3 was under anesthetic toxicity of accumulated isobutane which is a minor component of liquefied petroleum gas.- - - - - - - - - - ranking = 13keywords = gas (Clic here for more details about this article) |
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