Anesthesia and analgesia
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Anesthesia and analgesia · May 2004
Multiple measures of anesthesia workload during teaching and nonteaching cases.
In this study, we sought to examine several measures of anesthesia provider workload during different phases of anesthesia care and during teaching and nonteaching cases. Clinical work was assessed in real-time during 24 general anesthetics performed by consenting anesthesia providers. Workload was measured using physiological (provider heart rate), psychological (self-assessment and observer rating), and procedural (response latency to an alarm light and workload density) techniques. Clinicians' heart rates, observer and self-reported workload scores, and nonteaching workload density were consistently increased during anesthetic induction and emergence compared with maintenance. In nonteaching cases, workload density correlated with heart rate and with psychological workload. Workload density during teaching cases did not decrease during the induction and was significantly greater than during nonteaching cases. Alarm-light response latency (a measure of clinical vigilance) was significantly prolonged during the teaching compared with nonteaching cases. These results suggest that intraoperative teaching increases the workload of the clinician instructor and may reduce vigilance during anesthesia care. Additionally, multiple workload measures may provide a more comprehensive profile of the work demands of clinical cases. ⋯ Psychological, physiological, and procedural workload measures during routine general anesthesia cases documented the increased work demands of induction and emergence. Intraoperative teaching increased workload and decreased vigilance, suggesting the need for caution when educating during patient care.
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Anesthesia and analgesia · May 2004
Trends in the practice of parental presence during induction of anesthesia and the use of preoperative sedative premedication in the United States, 1995-2002: results of a follow-up national survey.
Both parental presence during induction of anesthesia and sedative premedication are currently used to treat preoperative anxiety in children. A survey study conducted in 1995 demonstrated that most children are taken into the operating room without the benefit of either of these two interventions. In 2002 we conducted a follow-up survey study. Five thousand questionnaires were mailed to randomly selected physician members of the American Society of Anesthesiologists. Mailings were followed by a nonresponse bias assessment. Twenty-seven percent (n = 1362) returned the questionnaire after 3 mailings. We found that a significantly larger proportion of young children undergoing surgery in the United States were reported to receive sedative premedication in 2002 as compared with 1995 (50% vs 30%, P = 0.001). We also found that in 2002 there was significantly less geographical variability in the use of sedative premedication as compared with the 1995 survey (F = 8.31, P = 0.006). Similarly, we found that in 2002 parents of children undergoing surgery in the United States were allowed to be present more often during induction of anesthesia as compared with 1995 (chi(2) = 26.3, P = 0.0001). Finally, similar to our findings in the 1995 survey, midazolam was uniformly selected most often to premedicate patients before surgery. ⋯ Over the past 7 yr there have been significant increases in the number of anesthesiologists who use preoperative sedative premedication and parental presence for children undergoing surgery.
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Anesthesia and analgesia · May 2004
Case ReportsWater intoxication and symptomatic hyponatremia after outpatient surgery.
Severe hyponatremia is associated with a mortality rate of more than 50%, primarily from cerebral edema and central nervous system dysfunction. Water intoxication is an unusual but potentially lethal cause of perioperative hyponatremia. We report a patient with severe postoperative hyponatremia resulting from excessive perioperative water consumption. Anesthesiologists should maintain an index of suspicion for hyponatremia from water intoxication in patients with neurologic symptoms during the perioperative period. Routine preoperative instructions regarding maximum perioperative water intake and inquiry into any concurrent alternative medical therapies may help to avoid this preventable complication. ⋯ Water intoxication is an unusual but potentially lethal cause of perioperative hyponatremia. We report a patient with severe postoperative hyponatremia resulting from excess perioperative water consumption.
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Anesthesia and analgesia · May 2004
The effects of isoflurane on desensitized wild-type and alpha 1(S270H) gamma-aminobutyric acid type A receptors.
gamma-aminobutyric acid type A receptors (GABA(A)-R) mediate synaptic inhibition and meet many pharmacological criteria required of important general anesthetic targets. During synaptic transmission GABA release is sufficient to saturate, maximally activate, and transiently desensitize postsynaptic GABA(A)-Rs. The resulting inhibitory postsynaptic currents (IPSCs) are prolonged by volatile anesthetics like isoflurane. We investigated the effects of isoflurane on maximally activated and desensitized GABA(A)-R currents expressed in Xenopus oocytes. Wild-type alpha(1)beta(2) and alpha(1)beta(2)gamma(2s) receptors were exposed to 600 microM GABA until currents reached a steady-state desensitized level. At clinical concentrations (0.02-0.3 mM), isoflurane produced a dose-dependent enhancement of steady-state desensitized current in alpha(1)beta(2) receptors, an effect that was less apparent in receptors including a gamma(2s)-subunit. When serine at position 270 is mutated to histidine (alpha(1)(S270H)) in the second transmembrane segment of the alpha(1)-subunit, the currents evoked by sub-saturating concentrations of GABA became less sensitive to isoflurane enhancement. In addition, isoflurane enhancements of desensitized currents were greatly attenuated by this mutation and were undetectable in alpha(1)(S270H)beta(2)gamma(2s) receptors. In conclusion, isoflurane enhancement of GABA(A)-R currents evoked by saturating concentrations of agonist is subunit-dependent. The effects of isoflurane on desensitized receptors may be partly responsible for the prolongation of IPSCs during anesthesia. ⋯ Isoflurane enhances desensitized gamma-aminobutyric acid type A receptor (GABA(A)-R) currents, an effect that is subunit-dependent and attenuated by a mutation in an alpha(1)-subunit pore residue of the GABA(A)-R. As GABA release at inhibitory synapses is typically saturating, isoflurane modulation of desensitized receptors may be partly responsible for prolongation of inhibitory postsynaptic currents during anesthesia.
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Anesthesia and analgesia · May 2004
Case ReportsFailed obstetric tracheal intubation and postoperative respiratory support with the ProSeal laryngeal mask airway.
The ProSeal laryngeal mask airway (ProSeal LMA) provides a better seal and probably better airway protection than the classic laryngeal mask airway (classic LMA). We report the use of the ProSeal LMA in a 26-yr-old female with HELLP syndrome for failed obstetric intubation and postoperative respiratory support. Both laryngoscope-guided tracheal intubation and face mask ventilation failed, but a size 4 ProSeal LMA was easily inserted and high tidal volumes obtained. A gastric tube was inserted through the ProSeal LMA drain tube and 300 mL of clear fluid was removed from the stomach. There were no hemodynamic changes during ProSeal LMA insertion. Postoperatively, the patient was transferred to the intensive care unit, where she was ventilated via the ProSeal LMA for 8 h until the platelet count had increased and she was hemodynamically stable. Weaning and ProSeal LMA removal were uneventful. There is anecdotal evidence supporting the use of the LMA devices for failed obstetric intubation (19 cases) and for postoperative respiratory support (8 cases). In principle, the ProSeal LMA may offer some advantages over the classic LMA in both these situations. ⋯ We report the successful use of the ProSeal laryngeal mask airway for failed obstetric intubation and postoperative respiratory support in a patient with HELLP syndrome.