Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2004
Neither the accuracy nor the precision of thermal dilution cardiac output measurements is altered by acute tricuspid regurgitation in pigs.
Whether measurement of cardiac output using the thermal dilution technique (TDCO) is valid in the presence of tricuspid regurgitation (TR) is controversial. We assessed the accuracy and precision of the technique in pigs by comparison with data from an electromagnetic flowmeter on the aorta (EMCO). TR was created with sutures that immobilized the free-wall leaflets of the tricuspid valve, and cardiac output was adjusted with dobutamine to give values comparable to control measurements. TR reduced forward stroke volume from 17.2 to 12.6 mL/beat and caused the right atrium to dilate and pulse in synchrony with the right ventricle. Acute TR did not affect the linear regression relation between TDCO and EMCO and did not alter the correlation coefficient (r = 0.94 during both control and TR). These data demonstrate that acute TR does not affect the accuracy or precision of TDCO in pigs. ⋯ Cardiac output is a valuable measurement that guides the medical care of patients with heart and lung disease. This study demonstrates that the thermal dilution technique of determining cardiac output is valid when acute tricuspid valve regurgitation is present in pigs.
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Anesthesia and analgesia · Apr 2004
Patient satisfaction with preoperative assessment in a preoperative assessment testing clinic.
Preoperative Assessment Testing Clinics (PATCs) coordinate preoperative surgical, anesthesia, nursing, and laboratory care. Although such clinics have been noted to lead to efficiencies in perioperative care, patient experience and satisfaction with PATCs has not been evaluated. We distributed a one-page questionnaire consisting of satisfaction with clinical and nonclinical providers to patients presenting to our PATC over three different time periods. Eighteen different questions had five Likert scale options that ranged from excellent (5) to poor (1). We achieved a 71.4% collection rate. The average for the subscale that indicated overall satisfaction was 4.48 +/- 0.67 and the average for the total instrument was 4.46 +/- 0.55. Although the highest scores were given for subscales describing the anesthesia, nurse, and lab, only the anesthesia subscale improved with time (P = 0.007). The subscale that involved information and communication had the highest correlation with the overall satisfaction subscale (r = 0.76; P < 0.0001). The satisfaction with the total duration of the clinic visit (3.71 +/- 1.26) was significantly less (P < 0.0001) than the satisfaction to the other items. The authors conclude that the practitioner and functional aspects of the preoperative visit have a significant impact on patient satisfaction, with information and communication versus the total amount of time spent being the most positive and negative components, respectively. ⋯ Patient satisfaction can serve as an important indicator of the quality of preoperative care delivered in Preoperative Assessment Testing Clinics (PATC). Information and communication, both from clinical and nonclinical service providers, remain the most important positive components, and the total duration of the clinic visit represents the most negative component, of patient satisfaction in a PATC.
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Anesthesia and analgesia · Apr 2004
The effects of propofol on hypothalamic paraventricular nucleus neurons in the rat.
The mechanism of hypotension induced by anesthetics is not completely understood. Because no electrophysiologic examination of the effects of propofol on the central nervous system has shown its involvement in the control of sympathetic and cardiovascular functions, we investigated the actions of propofol on rat hypothalamic paraventricular nucleus (PVN) neurons using the whole-cell mode of the patch-clamp technique in rat hypothalamic PVN slice preparations. Propofol induced Cl(-) currents at concentrations of 10(-5) and 10(-4) M, which were sensitive to picrotoxin and, to a lesser extent, to strychnine. Propofol (10(-6) M) enhanced gamma-aminobutyric acid(A) (GABA(A); 10(-6) M)-induced current synergistically. Moreover, propofol (10(-5) and 10(-4) M) significantly increased the decay time of evoked-inhibitory postsynaptic currents, which suggests a postsynaptic modulation of GABA(A) receptors. In addition, propofol (10(-5), 10(-4), and 2 x 10(-4) M) reversibly inhibited voltage-gated Ca(2+) currents. Taken together, these results suggest that propofol enhancement of GABA(A)-receptor mediated currents and inhibition of voltage-gated Ca(2+) currents at the central level, which is involved in the control of cardiovascular and sympathetic functions may be, at least in part, involved in general anesthetic-induced cardiovascular and sympathetic depression. ⋯ We investigated the actions of propofol on the rat hypothalamic paraventricular nucleus neurons, which are involved in the control of cardiovascular and sympathetic functions. The results suggest that propofol enhancement of gamma-aminobutyric acid(A)-receptor mediated currents and inhibition of voltage-gated Ca(2+) currents at the central level may be, at least in part, involved in general anesthetic-induced cardiovascular and sympathetic depression.