ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Malignant hyperthermia (MH) is currently diagnosed by the caffeine-halothane contracture (CHC) test. In a previous study, this test was used to establish linkage between the human gene for MH susceptibility and the ryanodine receptor (RYR) gene. The current study extends the genetic linkage analysis to a large French-Canadian kindred. In this family, genetic linkage between RYR and MH genes was not demonstrable using the currently recommended limits of normal for the CHC test in the identification of MH-susceptible individuals. With CHC test threshold limits below those currently recommended, however, complete linkage between the RYR and MH genes was seen. Comparisons of CHC test results with genetic linkage studies will increase the diagnostic accuracy of both tests as well as generate new insights into the biology of MH.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This randomized, double-blind study compared the analgesic and respiratory effects of lumbar epidural morphine 5 mg, nalbuphine 10 mg, and nalbuphine 20 mg in repeated doses in patients after thoracotomy; the first dose was administered intraoperatively. Pre-and postoperative monitoring included continuous pulse oximetry, respiratory inductance plethysmography, and repeated arterial blood gas analysis. Postoperatively, visual analogue pain scores, somnolence scores, respiratory rate, and arterial blood gases were determined for 16 h. Preoperatively, episodes of apnea were common during sleep but were not associated with low hemoglobin oxygen saturation or increased arterial carbon dioxide tension (Paco1). During sleep, some otherwise normal patients had increased PaCO2, and 2 of 15 patients had episodes of hemoglobin oxygen saturation of less than 90%. Postoperatively, 1 and 2 h after arrival in the recovery room, patients who received morphine had lower pain scores than did those who received nalbuphine 10 or 20 mg (P< 0.05). All 6 patients who received morphine had satisfactory analgesia. Two of 4 patients who received nalbuphine 10 mg and all 5 who received nalbuphine 20 mg were withdrawn from the study because of inadequate analgesta (morphinevs.nalbuphine 10 mg, not significant; morphinevs.nalbuphine 20 mg,P< 0.01). Two patients who received morphine had persistently increased PaCO2postoperatively. Two patients who received morphine had episodes of apnea and slow respiratory rate, which were most frequent 6 h after arrival in the recovery room. We conclude that lumbar epidural nalbuphine does not provide adequate analgesia after thoracotomy. Morphine is effective but may be associated with significant respiratory depression, which cannot be predicted on the basis of preoperative respiratory abnormalities, dose of drug, or hourly respiratory rate.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

There is no consensus as to the most appropriate monitor for detecting ischemia during carotid endarterectomy. Accordingly, simultaneous 16-channel continuous electroencephalogram (EEG) and somatosensory evoked potential (SSEP) monitoring were performed in 64 normocapnic patients undergoing carotid endarterectomy and anesthetized with isoflurane or halothane-nitrous oxide (supplemented with fentanyl). Recordings were obtained before, during, and for 15 min after cross-clamping of the internal carotid artery. Internal shunt was not used in any patient, regardless of EEG and SSEP changes. Significant amplitude reduction in the cortical component of the primary negative peak (>50%) in SSEP occurred in 6 patients, and an increase in central conduction time (CCT) (>1 ms) occurred in 5 patients. Major EEG changes occurred in 6 patients, 4 of whom also had SSEP changes. Two patients had transient neurologic deficits postoperatively, with both having SSEP changes (amplitude reduction > 50%), whereas one had EEG changes. Based on these observations, the relative sensitivity and specificity for EEG and SSEP (amplitude reduction > 50%) in detecting postoperative neurologic deficits were 50% and 92% for EEG and 100% and 94% for SSEP, respectively, differences that were not statistically significant. Regarding SSEP, the use of latency change (CCT) as a criterion was associated with a sensitivity of 0% (P= 0.046 from sensitivity of amplitude) and a specificity of 87% (P= 0.17 from specificity of amplitude). The authors concluded the following, regarding the use of EEG and SSEP as diagnostic tests of postoperative neurologic deficit: 1) both forms of electrophysiologic monitoring are associated with a considerable false-positive rate; 2) compared with conventional EEG, SSEP monitoring during carotid endarterectomy has a similar sensitivity and specificity; and 3) amplitude reduction greater than 50% is a better indicator than latency increase during SSEP monitoring.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Airway obstruction plays an important role in the pathogenesis of apnea in premature infants who have not previously undergone anesthesia. To determine the role of airway obstruction in postoperative apnea, we studied 74 former premature infants by integrated recordings of nasal airflow, pneumocardiography, and pulse oximetry during the initial 2 h of recovery from inhalational anesthesia. Apnea (> 6 s) was classified as central, obstructive, or mixed, wherein mixed apnea consisted of central and obstructive apnea within the same apneic episode. Postoperative apnea was observed in 23 infants, ranging in age from 31–48 weeks postconception: 12 had inguinal herniorrhaphy (hernia group) and 11 had other procedures (other group). Of the 268 apneic episodes in the hernia group, 73% were central, 6% obstructive, and 21% mixed. Infants in the other group had 505 apneic episodes, with a distribution nearly identical to that in the hernia group. Central and mixed apnea occurred in all infants experiencing apnea, except in 1 infant, who had only central apnea, whereas obstructive apnea occurred in only one third of the apneic infants. Arterial hemoglobin desaturation was significantly more frequent at the end of mixed and obstructive apnea than after central apnea (P< 0.01). In both groups, arterial hemoglobin O2saturation (Spo2, decreased to < 80% in approximately 35% of mixed and obstructive apneic episodes, compared to approximately 5% of central apneic episodes. Spo2, remained ≥ 90% in over 80% of central apneic episodes, compared to 40% of mixed and obstructive apneic episodes. These results demonstrate that airway obstruction is frequently a component of postoperative apnea and leads to a decrease in Spo2greater than that associated with apnea without obstruction.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

A prospective study was conducted to determine the prevalence of anemia in pediatric day-surgery patients, and a single-blinded study was conducted to evaluate the anesthesiologist's capability to detect preoperative anemia clinically. The subsequent management of children with anemia was noted. During the preoperative examination the anesthesiologist completed a questionnaire and predicted the preoperative hemoglobin concentration based on the history and physical examination. The preoperative hemoglobin concentration was measured for all of the patients, but the results were withheld until after completion of the questionnaire. Documentation was complete in 2,649 patients, and these comprised the final study group. Fourteen patients (0.5%) were anemic (hemoglobin concentration < 100 g/1), but of these, only 5 had been predicted to be anemic based on clinical examination. Seven of these 14 anemic patients were less than 1 yr of age. Only 2 of the anemic patients had surgery postponed, and 1 of these also had a respiratory infection. Forty-four patients were incorrectly predicted to be anemic (i.e., their actual hemoglobin concentration was greater than 100 g/1). We conclude that in our patients, anemia is rare but is more likely to occur in those less than 1 yr of age. The presence of mild degrees of anemia does not alter the decision to proceed with day surgery. The anesthesiologists participating in this study could not reliably detect anemia clinically.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The peripheral vascular effects of thiopental 5 mg/kg and propofol 2.5 mg/kg were compared in five patients whose lungs were being ventilated and in whom a Jarvik-7 artificial heart had been implanted. The patients were monitored, using catheters that had been surgically inserted into the radial artery, the right and left atria, and the pulmonary artery. The Jarvik-7 settings were modified to render the artificial heart “preload independent‘’ and to maintain cardiac output constant. Each patient received both drugs, with the interval between each drug ranging from 16 to 28 h. Hemodynamic parameters and catecholamine and atrial natriuretic peptide plasma concentrations were measured before drug administration and 5, 10, 15, 30, and 45 min later. Both drugs significantly decreased arterial pressure, systemic vascular resistance index, pulmonary arterial pressure (PAP), and right and left atrial pressures (RAP and LAP, respectively). However, propofol 2.5 mg/kg induced a significantly greater and more prolonged decrease in arterial pressure, systemic vascular resistance index, and RAP than that after administration of thiopental 5 mg/kg (P< 0.05). Five minutes after drug injection, mean arterial pressure decreased by 21% after thiopental and by 39% after propofol (P< 0.01); systemic vascular resistance index decreased by 21% after thiopental and by 44% after propofol (P< 0.05); RAP decreased by 20% after thiopental and by 50% after propofol (P< 0.05); mean PAP decreased by 18% after thiopental and by 32% after propofol (P< 0.09); and LAP decreased by 40% after thiopental and by 46% after propofol (P< 0.2). With both drugs, atrial natriuretic peptide, norepinephrine, and epinephrine plasma concentrations remained stable throughout the study period. Because cardiac output was maintained constant throughout the study, these results suggest that propofol 2.5 mg/kg is a more potent vasodilator of venous and arterial beds than is thiopental 5 mg/kg.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

To determine whether the calcium-magnesium-parathyroid hormone-calcitriol (vitamin D) axis responds appropriately to the hypocalcemia that routinely follows initiation of cardiopulmonary bypass (CPB), we measured blood ionized calcium (Ca1), total calcium (CaI), total magnesium (MgI), ultrafilterable magnesium (MgI), total protein, intact parathyroid hormone (PTH), and calcitriol concentrations at eight defined time points in 28 patients undergoing elective cardiac surgery. With the onset of CPB, CaIdecreased from 1.14 ± 0.02 to 0.91 ± 0.03 mM,P< 0.05) (n = 17), and then gradually returned to a normal value by the time of separation from CPB (0.98 ± 0.01 mM). CaI, MgI, MgI, and total protein concentrations declined significantly upon initiation of CPB and remained depressed thereafter. PTH initially decreased upon initiation of CPB (from 50 ± 8 to 24 ± 9 pg/ml, n = 9,P< 0.05), remained inappropriately decreased during the early phases of CPB, and then gradually increased to maximal concentrations in response to hypocalcemia (103 ± 15 pg/ml) before emergence. Calcitriol concentrations (n = 8) were unchanged during surgery. Based on these initial results, which suggested an association between hypomagnesemia and the slow PTH response to hypocalcemia, measurements were repeated in 10 additional patients, to whom magnesium (Mg) (1 g MgSO4in two separate intravenous doses) was administered. Mg administration neither altered the PTH response to ionized hypocaleemia nor hastened the return of CaIto normal. We conclude that MgI, MgI, and CaIconcentrations remain depressed at the time of separation froM CPB, but that routine supplemental administration of neither calcium (Ca) nor Mg is required for the restoration of normal Ca1values after CPB.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

An important guideline for anesthesia in patients with ischemic heart disease is the effect on myocardial oxygen demand. Therefore, this investigation evaluated commonly used myocardial oxygen demand formulas for clinical application. The study was performed on patients undergoing coronary bypass surgery (n=62). Measurements of standard hemodynamics were obtained before and after induction of anesthesia, as well as during sternotomy and after surgery. Coronary blood flow was determined by the argon wash-in technique. In 15 patients, a left ventricular tip manometer was used to accurately assess the first derivative of left ventricular pressure time course. The following indices of left ventricular oxygen demand were calculated: 1) rate pressure product (RPP); 2) tension time index (TTI); 3) pressure work index (PWI) according to the methods of Rooke; and 4) additive parameter (Eg), according to the methods of Bretschneider. All hemodynamic indices of myocardial oxygen demand showed moderate correlation with myocardial oxygen uptake (M&OV0312;o2) (RPP: ± = 0.77; TTI: ± = 0.79; PWI: ± = 0.79; Eg: ± = 0.71). On the average, PWI and Eg, led to an underestimation of M&OV0312;o2, in patients. The constants of the PWI and Egformulas, which have been developed based on animal experiments, therefore are not directly applicable to clinical conditions. New constants have been derived for PWI by multiple linear regression analysis of the data in the current investigation. The PWI formula thereby was modified for clinical application (PWImod= K1PsystHR + K2[0.8 Psyst+ 0.2 Pdiest] CI; K1= 8.37 ± 10-4, K2= 8.0 ± 10-6; where Psyst= systolic blood pressure, HR = heart rate; Pdiest= diastolic blood pressure, and CI = cardiac index) and retrospectively showed reasonably good correlation with M&OV0312;o2, (r = 0.84) in patients. The 95% limits of agreement between M&OV0312;o2and PWImodwere ±3.96 ml ± min-1± 100 g-1. The authors conclude from the current investigation that hemodynamic indices of myocardial oxygen demand derived from animal experiments cannot be applied to humans without modification.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Caudal epidural anesthesia has become widely accepted as a means of providing postoperative pain relief and intraoperative supplementation to general anesthesia for children. To determine the best concentration of bupivacaine for combined general-caudal anesthesia in children, 122 children aged 1–8 yr scheduled for outpatient inguinal herniorrhaphy were randomized to receive, in a double-blind fashion, caudal anesthesia with bupivacaine in one of six concentrations (0.125, 0.15, 0.175, 0.2, 0.225, or 0.25%). After incision, a programmed reduction in inspired halothane resulted, if tolerated by the subject, in an inspired halothane concentration of 0.5% 10 min after incision. End-tidal halothane concentration at hernia sac ligation for subjects receiving 0.175% bupivacaine (0.55 ± 0.03%) was less than that for subjects receiving 0.15% bupivacaine (0.75 ± 0.05%;P< 0.05). Subjects receiving 0.175% bupivacaine also were discharged earlier from the postanesthesia care unit (PACU) (27 ± 1 min) than were subjects receiving 0.15% bupivacaine (38 ± 5 min;P= 0.05). Children receiving ≥ 0.2% bupivacaine tended to complain more of leg weakness after surgery; however, the difference did not reach statistical significance (39 of 67vs.16 of 47;P= 0.057). The incidence of complaints of leg weakness and paresthesia was positively correlated with bupivacaine concentration (± = 0.706;P= 0.05). Subjects receiving 0.125% bupivacaine had higher pain scores on arrival to the PACU than did those receiving 0.2% bupivacaine (P= 0.05); there were no other differences in pain scores. Subjects receiving 0.175% bupivacaine ambulated sooner (129 ± 6 min) than did subjects receiving 0.125 and 0.2% bupivacaine (202 ± 20 min, 207 ± 21 min;P≤ 0.01). Subjects receiving 0.175% bupivacaine also were discharged home sooner (167 ± 8 min) than were subjects receiving 0.125 and 0.15% bupivacaine (248 ± 26 min, 255 ± 40 min;P≤ 0.05). Discharge home was delayed in subjects with ineffective intraoperative caudal supplementation (262 ± 27 minvs.196 ± 8 min;P< 0.01) and in subjects who received supplemental analgesics (253 ± 16 minvs.177 ± 17 min;P< 0.001). Although all concentrations were effective for combined general-caudal anesthesia in children, we conclude that 0.175% bupivacaine offers the best combination of effectiveness and rapid recovery and discharge for pediatric surgical outpatients.

ISSN:0003-3022    

出版商:OVID    

年代:1991

数据来源: OVID