Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2010
Ventilation-perfusion ratio in perflubron during partial liquid ventilation.
Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detected Pao(2). We investigated this approach by numerical simulations and applied it to quantify local Va/Q in the perfluorocarbons during partial liquid ventilation. ⋯ The results show that derivation of Va/Q from local Po(2) measurements using fMRI in perflubron is feasible. The low detected Va/Q suggests that oxygen transport into the perflubron-filled alveolar space is significantly restrained.
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Anesthesia and analgesia · Jun 2010
Case ReportsCase reports: management of intractable upper extremity pain with continuous subarachnoid block at the low cervical level without impairment of upper extremity function.
We present a case of continuous subarachnoid block for the treatment of refractory cancer pain in the shoulder and upper extremity on the right side of the patient. The catheter tip was placed in the subarachnoid space close to the nerve roots on the right side at the height of C5 corresponding to the painful region. Until the patient died, his pain was controlled with infusions of bupivacaine (30-58.7 mg/d) and morphine (2-19.6 mg/d) for 120 days during which upper extremity function was not disturbed and respiratory function and performance status were improved. This case suggests continuous subarachnoid block at the low cervical level is useful for refractory cancer pain in the shoulder and upper extremity.
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Anesthesia and analgesia · Jun 2010
What will anesthesiologists be anesthetizing? Trends in neurosurgical procedure usage.
To anticipate future changes to the practice of neuroanesthesia, we examined the nationwide trends in frequently performed operative neurosurgery. ⋯ The highest volume trends in operative neurosurgery are for spinal fusion (increasing at a rate of approximately 12,000 procedures/y), craniotomy for tumors and other purposes (increasing at a rate of approximately 2,700 procedures/y), and a decrease in shunts (decreasing at a rate of approximately 3,000 per year). The data suggest that intracranial endovascular treatment remains relatively rare, but it is growing exponentially, and lengths of stay are increasing, whereas inhospital deaths are decreasing. The conclusions of this study are limited by the imprecise nature of the ICD-9-CM procedure codes, the categorization scheme we used, and by the sampling methods of the National Inpatient Sample.
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Anesthesia and analgesia · Jun 2010
Low tidal volume and high positive end-expiratory pressure mechanical ventilation results in increased inflammation and ventilator-associated lung injury in normal lungs.
Protective mechanical ventilation with low tidal volume (Vt) and low plateau pressure reduces mortality and decreases the length of mechanical ventilation in patients with acute respiratory distress syndrome. Mechanical ventilation that will protect normal lungs during major surgical procedures of long duration may improve postoperative outcomes. We performed an animal study comparing 3 ventilation strategies used in the operating room in normal lungs. We compared the effects on pulmonary mechanics, inflammatory mediators, and lung tissue injury. ⋯ Comparing intraoperative strategies, ventilation with high PEEP resulted in increased production of inflammatory markers. Low PEEP resulted in lower levels of inflammatory markers. High Vt/low PEEP resulted in less histologic lung injury.
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Anesthesia and analgesia · Jun 2010
Brief report: effects of positive end-expiratory pressure on internal jugular vein cross-sectional area in anesthetized adults.
We tested whether positive end-expiratory pressure (PEEP) increases right internal jugular vein (RIJV) cross-sectional area (CSA) in 45 ASA physical status I and II adults. All patients received a standardized IV fluid bolus, induction of general anesthesia, tracheal intubation, and mechanical ventilation. We evaluated the CSA of the RIJV using ultrasound without PEEP (control) and with PEEP (10 cm H(2)O) in the supine, level position. Addition of PEEP increased RIJV CSA 0.42 + or - 0.41 cm(2) (mean + or - SD, median 0.34 cm(2), P < 0.001), which represented a 41% mean increase in CSA.