Anesthesiology
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Adverse reactions to drugs require that their mechanisms be elucidated, particularly when anaphylaxis is suspected. Early diagnosis can be achieved by plasma histamine measurements. Unfortunately, the short plasma half-life of histamine and the difficulties in handling the sample usually preclude this measurement, although a sensitive radioimmunologic kit is routinely available. ⋯ At least 15 min was necessary to reach the peak level when the responsible drug was administered intravenously. The best time for measuring tryptase was 1-2 h after the reaction (not greater than 6 h), whereas for histamine it was 10 min to 1 h. We conclude that measurement of plasma tryptase along with measurement of plasma histamine may aid in diagnosis of anaphylaxis.
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Although epinephrine increases cerebral blood flow (CBF) and left ventricular blood flow (LVBF) during cardiopulmonary resuscitation (CPR), the effects of high dosages on LVBF and CBF and cerebral O2 uptake have not been examined during prolonged CPR. We determined whether log increment dosages of epinephrine would enhance LVBF and CBF and cerebral O2 uptake in an infant swine CPR model. We compared these responses with epinephrine to those with the alpha-adrenergic agonist, phenylephrine. ⋯ Incremental dosages of epinephrine did not statistically increase cerebral O2 uptake or lower the cerebral fractional O2 extraction when compared with the control group, despite the higher CBF that was generated. In this immature animal CPR model, 10 micrograms.kg-1.min-1 epinephrine is an optimal dosage for maximizing both CBF and LVBF, a dosage that substantially exceeds the current recommended epinephrine dosage for human infant CPR. In addition, for short periods of CPR, 40 micrograms.kg-1.min-1 phenylephrine increases CBF and LVBF to levels similar to those generated by high dosages of epinephrine.
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Review
Management of the difficult adult airway. With special emphasis on awake tracheal intubation.
Difficulty in managing the airway is the single most important cause of major anesthesia-related morbidity and mortality. Successful management of a difficult airway begins with recognizing the potential problem. All patients should be examined for their ability to open their mouth widely and for the structures visible upon mouth opening, the size of the mandibular space, and ability to assume the sniff position. ⋯ Eighty percent of the 127 references in this article were published after 1985. However, there is much more to learn with regard to recognition of the difficult airway, preparation of the patient for an awake intubation, new techniques of endotracheal intubation, and establishment of gas exchange in patients who cannot be intubated or ventilated by mask. As the anesthesiologist's ability to manage the difficult airway significantly improves, respiratory-related morbidity and mortality will decrease.
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Adverse outcomes associated with respiratory events are the single largest class of injury in the American Society of Anesthesiologists Closed Claims Project (762 of the 2,046 cases, 37%). Inadequate ventilation, esophageal intubation, and difficult tracheal intubation are the most common mechanisms of respiratory-related adverse outcomes. An analysis of closed claims data regarding these mechanisms has been reported previously. ⋯ Aspiration (56 claims, 3% of the database) usually occurred during general anesthesia, either during induction prior to tracheal intubation or during maintenance of anesthesia delivered via mask. Bronchospasm (40 claims, 2% of the database) tended to occur during induction of general anesthesia in patients with a history of asthma or chronic obstructive pulmonary disease and/or smoking. The incidence of severe injury (brain damage and death) among these cases in the five categories was 47% overall, ranging from 12% in airway trauma claims to nearly 90% in claims for airway obstruction and bronchospasm.(ABSTRACT TRUNCATED AT 250 WORDS)