Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2002
Bispectral index values and spectral edge frequency at different stages of physiologic sleep.
Bispectral index (BIS) and spectral edge frequency (SEF) are used as measures of depth of anesthesia and sedation. We tested whether these signals could predict physiologic sleep stages, by taking processed electroencephalogram measurements and recording full polysomnography through a night's sleep in 10 subjects being investigated for mild sleep apnea/hypopnea syndrome. Computerized polysomnograph signals were analyzed manually according to standard criteria, classifying each 30-s epoch as a specific sleep stage. The BIS and SEF values were taken at the end of each period of sleep when the same stage had lasted for at least 2 min. Before sleep, median values for BIS were 97 +/- 12.1 and for SEF 23 +/- 4.2 Hz. After sleep initiation, the median BIS values for arousal, light, slow wave, and rapid eye movement sleep were 67 +/- 20.2, 50 +/- 16.5, 42 +/- 11.2, and 48 +/- 7.1, respectively, and the median SEF values were 20 +/- 4.7, 15 +/- 3.6, 10 +/- 2.6, and 19 +/- 4.1 Hz, respectively. Although both BIS and SEF decreased with increasing sleep depth, the distribution of values at each sleep depth was considerable, with overlap between each sleep stage. Neither BIS nor SEF reliably indicated conventionally determined sleep stages. In addition, the response of the BIS was slow and patients could arouse with low BIS values, which then took some time to increase. ⋯ Although computer processing of the electroencephalogram can provide an adequate index of depth of anesthesia, the same processing cannot reliably convey depth of natural sleep. At each sleep stage, the output signal has a wide range of possible values.
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Opening of the first door of pulse photometry gave us pulse oximeter. The next door opens to multiwavelength pulse photometry. It will give us a high performance pulse oximeter, providing a wide variety of clinical information simultaneously. This next generation of pulse photometry should further improve bedside monitoring and patient care.
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Anesthesia and analgesia · Jan 2002
Case ReportsHuman error: the persisting risk of blood transfusion: a report of five cases.
It is common experience that virus transmission, particularly transmission of the human immunodeficiency virus (HIV), is a principal concern of patients and physicians regarding blood transfusion (1). Many physicians are probably unaware that transfusion-transmitted HIV infection is approximately 50 to 100 times less likely to occur than transfusion error (2-4). This misconception may have been encouraged by the scarcity of reports on transfusion error relative to the tremendous public attention focused on HIV infection. We present five cases illustrating how anesthesiologists, intensivists, and emergency physicians are particularly vulnerable to the risk of administering blood to the wrong recipient. All five cases were collected during a 4-yr period. Transfused units of packed red cells totaled approximately 50,000 U during this period in our department. ⋯ Human error leading to the transfusion of blood to an unintended recipient is a major source of transfusion-related fatalities. We report five cases that highlight some specific areas in which transfusion error is likely to occur.
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Anesthesia and analgesia · Jan 2002
Peripheral nerve blockade with long-acting local anesthetics: a survey of the Society for Ambulatory Anesthesia.
Despite the growth of ambulatory anesthesia and the renewed popularity of regional techniques, there is little current information concerning outpatient regional anesthesia practices or attitudes about discharge with an insensate extremity. We present results from a survey sent to all members of the Society for Ambulatory Anesthesia (SAMBA). The survey was mailed in January 2001 to 2373 SAMBA members, along with a self-addressed stamped return envelope. After 3 mo, 1078 surveys were returned (response rate 45%). Respondents indicated that they were most likely to perform axillary (77%), interscalene (67%), and ankle blocks (68%) on ambulatory patients. They were less likely to perform lower extremity conduction blocks in ambulatory patients (femoral blocks, 40%; all other types of blocks, <23%]. Eighty-five percent of respondents discharged patients with long-acting blocks, but this was mainly limited to three types. Of the 16% who never or rarely discharged patients with long-acting blocks, the primary reasons were concern about patient injury (49%) and the inability for patients to care for themselves (28%). Only 22% of office-based anesthesiologists would perform upper extremity blocks and only 28% would perform lower extremity blocks (P < 0.001). This survey demonstrates that use of regional anesthesia in outpatients is common but restricted to a few techniques. Discharge with an insensate upper extremity is prevalent but discharge with an insensate lower extremity is not common and remains controversial. Despite the reasoning for the reported practices, randomized data are necessary to confirm the validity of these concerns. ⋯ This survey demonstrates that use of regional anesthesia in outpatients is common but restricted to a few techniques. Discharge with an insensate upper extremity is common but discharge with an insensate lower extremity is not prevalent and remains controversial.
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Anesthesia and analgesia · Jan 2002
Case ReportsProlongation of rapacuronium neuromuscular blockade by clindamycin and magnesium.
We report a prolonged neuromuscular block with the nondepolarizing muscle relaxant rapacuronium in the presence of clindamycin. Even when using "short-acting" muscle relaxants, the anesthesiologist must routinely monitor the neuromuscular function.