Anesthesiology
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An Automated Oscillometric Technique for Estimating Mean Arterial Pressure in Critically III Newborns
Anesthesiology - Tập 54 Số 5 - Trang 423-425 - 1981
Propofol Neurotoxicity Is Mediated by p75 Neurotrophin Receptor Activation
Background
Propofol exposure to neurons during synaptogenesis results in apoptosis, leading to cognitive dysfunction in adulthood. Previous work from our laboratory showed that isoflurane neurotoxicity occurs through p75 neurotrophin receptor (p75(NTR)) and subsequent cytoskeleton depolymerization. Given that isoflurane and propofol both suppress neuronal activity, we hypothesized that propofol also induces apoptosis in developing neurons through p75(NTR).
Methods
Days in vitro 5-7 neurons were exposed to propofol (3 μM) for 6 h and apoptosis was assessed by cleaved caspase-3 (Cl-Csp3) immunoblot and immunofluorescence microscopy. Primary neurons from p75(NTR-/-) mice or wild-type neurons were treated with propofol, with or without pretreatment with TAT-Pep5 (10 μM, 15 min), a specific p75(NTR) inhibitor. P75(NTR-/-) neurons were transfected for 72 h with a lentiviral vector containing the synapsin-driven p75(NTR) gene (Syn-p75(NTR)) or control vector (Syn-green fluorescent protein) before propofol. To confirm our in vitro findings, wild-type mice and p75(NTR-/-) mice (PND5) were pretreated with either TAT-Pep5 or TAT-ctrl followed by propofol for 6 h.
Results
Neurons exposed to propofol showed a significant increase in Cl-Csp3, an effect attenuated by TAT-Pep5 and hydroxyfasudil. Apoptosis was significantly attenuated in p75(NTR-/-) neurons. In p75(NTR-/-) neurons transfected with Syn-p75(NTR), propofol significantly increased Cl-Csp3 in comparison with Syn-green fluorescent protein-transfected p75(NTR-/-) neurons. Wild-type mice exposed to propofol exhibited increased Cl-Csp3 in the hippocampus, an effect attenuated by TAT-Pep5. By contrast, propofol did not induce apoptosis in p75(NTR-/-) mice.
Conclusion
These results demonstrate that propofol induces apoptosis in developing neurons in vivo and in vitro and implicate a role for p75(NTR) and the downstream effector RhoA kinase.
Anesthesiology - Tập 116 Số 2 - Trang 352-361 - 2012
Postoperative Cognitive Dysfunction after Noncardiac Surgery This article describes a systematic review on the research into postoperative cognitive dysfunction (POCD) in noncardiac surgery to ascertain the status of the evidence and to examine the methodologies used in studies. The review demonstrated that in the early weeks after major noncardiac surgery, a significant proportion of people show POCD, with the elderly being more at risk. Minimal evidence was found that patients continue to show POCD up to 6 months and beyond. Studies on regional versus general anesthesia have not found differences in POCD. Many studies were found to be underpowered, and a number of other methodologic difficulties were identified. These include the different types of surgery in studies and variations in the number and range of neuropsychological tests used. A particular issue is the variety of definitions used to classify individuals as having POCD.
Anesthesiology - Tập 106 Số 3 - Trang 572-590 - 2007
Spinal Pharmacology of Thermal Hyperesthesia Induced by Incomplete Ligation of Sciatic Nerve I. Opioid and Nonopioid Receptors
Anesthesiology - Tập 75 Số 5 - Trang 817-826 - 1991
Acute Pulmonary Edema in Healthy Teenagers Following Conservative Doses of Intravenous Naloxone
Anesthesiology - Tập 60 Số 5 - Trang 485-486 - 1984
Tidal Volume Lower than 6 ml/kg Enhances Lung Protection
Background
Tidal hyperinflation may occur in patients with acute respiratory distress syndrome who are ventilated with a tidal volume (VT) of 6 ml/kg of predicted body weight develop a plateau pressure (PPLAT) of 28 < or = PPLAT < or = 30 cm H2O. The authors verified whether VT lower than 6 ml/kg may enhance lung protection and that consequent respiratory acidosis may be managed by extracorporeal carbon dioxide removal.
Methods
PPLAT, lung morphology computed tomography, and pulmonary inflammatory cytokines (bronchoalveolar lavage) were assessed in 32 patients ventilated with a VT of 6 ml/kg. Data are provided as mean +/- SD or median and interquartile (25th and 75th percentile) range. In patients with 28 < or = PPLAT < or = 30 cm H2O (n = 10), VT was reduced from 6.3 +/- 0.2 to 4.2 +/- 0.3 ml/kg, and PPLAT decreased from 29.1 +/- 1.2 to 25.0 +/- 1.2 cm H2O (P < 0.001); consequent respiratory acidosis (Paco2 from 48.4 +/- 8.7 to 73.6 +/- 11.1 mmHg and pH from 7.36 +/- 0.03 to 7.20 +/- 0.02; P < 0.001) was managed by extracorporeal carbon dioxide removal. Lung function, morphology, and pulmonary inflammatory cytokines were also assessed after 72 h.
Results
Extracorporeal assist normalized Paco2 (50.4 +/- 8.2 mmHg) and pH (7.32 +/- 0.03) and allowed use of VT lower than 6 ml/kg for 144 (84-168) h. The improvement of morphological markers of lung protection and the reduction of pulmonary cytokines concentration (P < 0.01) were observed after 72 h of ventilation with VT lower than 6 ml/kg. No patient-related complications were observed.
Conclusions
VT lower than 6 ml/Kg enhanced lung protection. Respiratory acidosis consequent to low VT ventilation was safely and efficiently managed by extracorporeal carbon dioxide removal.
Anesthesiology - Tập 111 Số 4 - Trang 826-835 - 2009
Prospective, Randomized Trial Comparing General with Spinal Anesthesia for Cesarean Delivery in Preeclamptic Patients with a Nonreassuring Fetal Heart Trace
Background
There are no randomized studies on neonatal outcome after spinal versus general anesthesia for cesarean delivery in preeclamptic patients with a nonreassuring fetal heart trace. This study examined both markers of neonatal hypoxia and maternal hemodynamics.
Methods
Seventy patients were randomized to general (n = 35) or spinal anesthesia (n = 35). The general anesthesia group received thiopentone, magnesium sulfate, and suxamethonium intravenously before intubation, followed by 50% nitrous oxide in oxygen, 0.75-1.5% isoflurane, and morphine after delivery. The target end-tidal partial pressure of carbon dioxide (Pco2) was 30-34 mmHg. The spinal anesthesia group received 1.8 ml hyperbaric bupivacaine plus 10 microg fentanyl at the L3-L4 interspace. Heart rate and blood pressure were measured at specific time points. Hypotension was treated with ephedrine. Maternal arterial and neonatal umbilical arterial blood gas samples were taken at delivery. Resuscitation requirements were recorded.
Results
In both groups, hemodynamic measures remained within acceptable limits. Spinal anesthesia patients required more ephedrine (13.7 vs. 2.7 mg). Maternal Paco2 was lower in the spinal group (28.9 vs. 32.4 mmHg). One-minute Apgar scores were lower after general anesthesia. Base deficit was greater (7.13 vs. 4.68 mEq/l) and neonatal umbilical arterial pH was lower (7.20 vs. 7.23) after spinal anesthesia. Post hoc analysis showed that if maternal diastolic blood pressure on admission was greater than 110 mmHg, neonatal umbilical arterial base deficit was greater after spinal anesthesia. There was no difference in the number of patients with Apgar scores less than 7 at 1 or 5 min or umbilical arterial pH less than 7.2 or in the requirements for resuscitation.
Conclusions
In preeclamptic patients with a nonreassuring fetal heart trace, spinal anesthesia for cesarean delivery was associated with a greater mean neonatal umbilical arterial base deficit and a lower median umbilical arterial pH. The clinical significance remains to be established. Maternal hemodynamics were similar and acceptable with either anesthetic technique.
Anesthesiology - Tập 99 Số 3 - Trang 561-569 - 2003
Effects of Crystalloid and Colloid Preload on Blood Volume in the Parturient Undergoing Spinal Anesthesia for Elective Cesarean Section
Background
The role of crystalloid preloading to prevent hypotension associated with spinal anesthesia in parturients during cesarean section has been challenged. Direct measurement of blood volume should provide insight regarding the volume-expanding effects. The aim of the current study was to clarify the effects of volume preload with either crystalloid or colloid solution on the changes in blood volume of parturients undergoing spinal anesthesia for cesarean section.
Methods
Thirty-six healthy parturients scheduled for elective cesarean section during spinal anesthesia were allocated randomly to one of three groups receiving 1.5 l lactated Ringer's solution (LR; n = 12), 0.5 l hydroxyethylstarch solution, 6% (0.5 l HES; n = 12), and 1.0 l hydroxyethylstarch solution, 6% (1.0 l HES; n = 12), respectively. Blood volume and cardiac output were measured before and after volume preloading with indocyanine green (ICG), and the indocyanine green blood concentrations were monitored by noninvasive pulse spectrophotometry.
Results
After volume preload, the blood volume significantly increased in all three groups (P < 0.01). The volume of infused solution remaining in the vascular space in the LR, 0.5-l HES, and 1.0-l HES groups were 0.43+/-0.20 l, 0.54+/-0.14 l, and 1.03+/-0.21 l, respectively, corresponding to 28% of lactated Ringer's solution and 100% of hydroxyethylstarch solution infused. Significant increases in cardiac output were observed in the 0.5-l and 1.0-l HES groups (P < 0.01). A significant correlation between the percentage increase in blood volume and that of cardiac output was observed by volume preloading (r2 = 0.838; P < 0.001). The incidence of hypotension was 75% for the LR group, 58% for the 0.5-l HES group, and 17% for the 1.0-l HES group, respectively.
Conclusions
The incidence of hypotension developed in the 1.0-l HES group was significantly lower than that in the LR and 0.5-l HES groups, showing that greater volume expansion results in less hypotension. This result indicates that the augmentation of blood volume with preloading, regardless of the fluid used, must be large enough to result in a significant increase in cardiac output for effective prevention of hypotension.
Anesthesiology - Tập 91 Số 6 - Trang 1571-1571 - 1999
The Effects of Epidural Ropivacaine and Bupivacaine for Cesarean Section on Uteroplacental and Fetal Circulation
Background
Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function.
Methods
Healthy parturient women with singleton, uncomplicated pregnancies at term received 115-140 mg 0.5% ropivacaine (n = 11) or 0.5% bupivacaine (n = 10) in incremental epidural doses. The first ultrasound measurement was performed before injection of the study drug. Pulsatility indexes (PI) were derived for the blood flow velocity waveforms of the maternal placental and nonplacental uterine arteries; the placental arcuate artery; and the fetal umbilical, middle cerebral, and renal arteries. The fetal heart then was examined by echocardiography. The PI of the maternal uterine arteries and the fetal umbilical artery were measured 5 min after the injection of the local anesthetic. When sensory analgesia had reached the T6-T4 level, the ultrasound measurement was repeated with the same methods and targets as in the baseline measurement.
Results
Both drugs provided adequate surgical anesthesia for cesarean section. In the bupivacaine group, the PI values for the maternal placental and nonplacental uterine arteries increased significantly 5 min after the main dose (P = 0.01, P = 0.002) and when sensory analgesia had reached the T6-T4 level (P = 0.004, P = 0.01) as compared with the baseline measurement. Simultaneously, the PI in the fetal middle cerebral artery decreased significantly (P = 0.02). The PI for the maternal uterine artery increased significantly (P = 0.01) after ropivacaine administration but only on the nonplacental side and not until sensory analgesia had reached the T6-T4 level. No effect on the Doppler indexes obtained from the umbilical artery was observed in either group. There were no significant differences relative to baseline values in any fetal myocardial measurement or in any ultrasound measurement between the groups. Neither drug had any detrimental effect on Apgar scores or umbilical cord acid-base status. None of the neonates' conditions was markedly depressed according to neurobehavioral testing.
Conclusions
Within this small study, epidural 0.5% ropivacaine for cesarean section did not compromise the utero-placental circulation in healthy parturient women with uncomplicated pregnancies. It provided surgical anesthesia that was equally effective as that provided by 0.5% bupivacaine.
Anesthesiology - Tập 83 Số 1 - Trang 23-32. - 1995
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