ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundMonitoring left ventricular preload is critical to achieve adequate fluid resuscitation in patients with hypotension and sepsis. This prospective study tested the correlation of the pulmonary artery occlusion pressure, the left ventricular end‐diastolic area index measured by transesophageal echocardiography, the arterial systolic pressure variation (the difference between maximal and minimal systolic blood pressure values during one mechanical breath), and its delta down (dDown) component (= apneic ‐ minimum systolic blood pressure) with the response of cardiac output to volume expansion during sepsis.MethodsPreload parameters were measured at baseline and during graded volume expansion (increments of 500 ml) in 15 patients with sepsis‐induced hypotension who required mechanical ventilation. Each volume‐loading step (VLS) was classified as a responder (increase in stroke volume index >or= to 15%) or a nonresponder. Successive VLSs were performed until a nonresponder VLS was obtained.ResultsThirty‐five VLSs (21 responders) were performed. Fluid loading caused an overall significant increase in pulmonary artery occlusion pressure and end‐diastolic area index, and a significant decrease in systolic pressure variation and delta down (P < 0.01). There was a significant difference between responder and nonresponder VLSs in end‐diastolic area index, systolic pressure variation, and dDown, but not in pulmonary artery occlusion pressure. Receiver‐operator curve analysis showed that dDown was a more accurate indicator of the response of stroke volume index to volume loading than end‐diastolic area index and pulmonary artery occlusion pressure. A dDown component of more than 5 mmHg indicated that the stroke volume index would increase in response to a subsequent fluid challenge (positive and negative predictive values: 95% and 93%, respectively).ConclusionThe dDown component of the systolic pressure variation is a sensitive indicator of the response of cardiac output to volume infusion in patient with sepsis‐induced hypotension who require mechanical ventilation.

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundIn the treatment of critically ill patients, blood volume (BV) measurement requires injection of some tracer substance and subsequent blood sampling to analyze the tracer concentration. To obviate both the sampling and laboratory analysis, techniques of pulse oximetry have been adapted to the noninvasive optical measurement in the patient's nose or finger of the arterial concentration of an injectable dye.MethodsThe authors report the clinical accuracy of a new noninvasive bedside BV measurement test that uses pulse spectrophotometry (the pulse method). The device detects pulsatile changes of tissue optical density of a nostril or a finger spanned by a probe emitting two infrared wavelengths (805 and 890 nm). After a peripheral or central intravenous injection of indocyanine green, the arterial dye concentration is continuously computed by reference to the previously measured blood hemoglobin concentration. Three types of tests of its accuracy are described here.ResultsIn 10 healthy volunteers, the authors compared BV determined by the pulse method with an131I‐labeled human serum albumin method. Three subject data sets were excluded because of motion artifact, a low signal:noise ratio, or both. For the other seven volunteers, the bias +/− SD of pulse spectrophotometric BV values were 0.20 +/− 0.24 1 (or 4.2 +/− 4.9%) for the nose probe and 0.34 +/− 0.31 1 (or 7.3 +/− 6.9%) for the finger probe, with a mean BV of 5 l. In 30 patients who underwent cardiac surgery, the pulse method was compared with a standard indocyanine green method using intermittent blood sampling. In three patients, the BV could not be determined by the pulse method because of motion artifact, low signal:noise ratio, or both. In 27 patients, the bias +/− SD of the BV by the pulse method was ‐0.23 +/− 0.37 l (‐5.3 +/− 8.7%) for the nose and ‐0.25 +/− 0.5 l (‐4.2 +/− 8.4%) for the finger. Patient BV ranged from 2.51 to 7.13 l (mean, 4.48 l). In 10 additional patients before cardiac surgery, BV was measured by the pulse method before and shortly after removal of 400 ml blood. The pulse method recorded a decrease of BV of 480 +/− 114 ml. Three days after venesection, the mean BV was 117 +/− 159 ml less than the predonation control.ConclusionsIn most patients, the pulse method provides bedside measurement of BV without blood sampling (except for hemoglobin determination), with an estimated error less than 10%. In 10‐30% of tests the method failed because of motion distortion of the record during the 10‐min data collection period or because of insufficient pulse amplitude in the test tissue.

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundPulse dye‐densitometry (PDD) is a newly developed technique for monitoring the arterial concentration of indocyanine green. Using this method, circulating blood volume (CBV) can be calculated without using radioisotopes. In this study, the CBV value obtained by PDD was validated by comparison using the human serum albumin (131) I‐HSA) dilution method.MethodsEleven healthy volunteers underwent placement of cannulae into the radial artery and antecubital vein for withdrawal of blood samples and injection of indicator. Probes for PDD were attached to the right nostril and the right index finger. Indocyanine green (20 mg), dissolved in 4 ml water, and 25 [micro sign]Ci131I‐HSA in 1 ml distilled water were injected simultaneously into the left antecubital vein. Blood samples were withdrawn 3, 6, 10, 20, 30, and 45 min after injection, then processed for spectrophotometric measurement of indocyanine green and scintillation counting.ResultsThe blood dye concentration correlated well with the values obtained by PDD (r = 0.986, imprecision 0.04 +/− 0.11 mg/l, 10.0 +/− 31%. The imprecision of the CBV value obtained by PDD (nose probe) and by the131I‐HSA dilution method was 3.99 +/− 10.54%, 0.259 +/− 0.593 l. The imprecision of the CBV obtained by in vitro spectrophotometry compared with PDD was 2.47 +/− 9.00%, 0.100 +/− 0.446 l.ConclusionsThis newly developed, less invasive method can measure CBV with an imprecision of 3.99 +/− 10.54%, 0.259 +/− 0.593 l (nose probe), and thus is also as accurate as the conventional radioisotope method

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundCombined spinal‐epidural (CSE) analgesia produces rapid‐onset pain relief and allows ambulation in early labor. Epidural local anesthetics may contribute to an increase in operative deliveries by decreasing perineal sensation and causing motor weakness. Operative delivery rates might be reduced with CSE, by avoiding or delaying administration of local anesthetics. This study compares the operative delivery rates associated with a CSE technique and those associated with intravenous meperidine for labor analgesia.MethodsHealthy parturients at full term were assigned randomly to receive CSE or intravenous meperidine analgesia. The CSE group received 10 [micro sign]g intrathecal sufentanil, followed by epidural bupivacaine and fentanyl at their next request for analgesia. Parturients receiving intravenous meperidine had 50 mg on demand (maximum, 200 mg in 4 h). Labor and delivery outcomes in both groups were recorded and compared.ResultsAn intent‐to‐treat analysis of 1,223 women indicated that CSE does not increase the rate of cesarean delivery for dystocia in nulliparous and parous women (CSE, 3.5% vs. intravenous meperidine, 4; P = not significant) or in nulliparous women alone (CSE, 7% vs. intravenous meperidine, 8%; P = not significant). Profound fetal bradycardia that necessitated emergency cesarean delivery within 1 h of the time the mother received sufentanil occurred in 8 of 400 parturients (compared with 0 of 352 who received meperidine; P < 0.01). However, the method of fetal monitoring differed between the two groups. Despite this, neonatal outcomes were similar overall.ConclusionsCombined spinal‐epidural analgesia during labor does not increase the cesarean delivery rate for dystocia in healthy parturient patients at full term, regardless of parity. However, an unexpected increase in the number of cesarean deliveries for profound fetal bradycardia after intrathecal sufentanil was observed. Further investigation is warranted.

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

BackgroundThe antinociceptive effects of systemically administered local anesthetics have been shown in various conditions, such as neuralgia, polyneuropathy, fibromyalgia, and postoperative pain. The objective of the study was to identify the peripheral mechanisms of action of low‐dose local anesthetics in a model of experimental pain.MethodsIn a first experimental trial, participants (n = 12) received lidocaine systemically (a bolus injection of 2 mg/kg in 10 min followed by an intravenous infusion of 2 mg [middle dot]‐1[middle dot] h‐1for another 50 min). In a second trial, modified intravenous regional anesthesia was administered to exclude possible central analgesic effects. In one arm, patients received an infusion of 40 ml lidocaine, 0.05%; in their other arm, 40 ml NaCl, 0.9%, served as a control. In both trials, calibrated tonic and phasic mechanical and chemical (histamine) stimuli were applied to determine differentially the impairment of tactile and nociceptive perception.ResultsMechanical sensitivity to touch, phasic mechanical stimuli of noxious intensity, and heat pain thresholds remained unchanged after systemic and regional application of the anesthetic. In contrast, histamine‐induced itch (intravenous regional anesthesia), axon reflex flare (systemic treatment), and development of acute mechanical hyperalgesia during tonic pressure (12 N; 2 min) of an interdigital web was significantly suppressed after both treatments.ConclusionsIncreasing painfulness during sustained pinching has been attributed to excitation and simultaneous sensitization of particular A [small sigma, Greek]‐ and C‐nociceptors. This hyperalgesic mechanism seems to be particularly sensitive to low concentrations of lidocaine. These findings confirm clinical experience with lidocaine in pain states dominated by hyperalgesia.

ISSN:0003-3022    

出版商:OVID    

年代:1998

数据来源: OVID