The effect of sevoflurane on cerebral blood flow velocity in children

BACKGROUND: Sevoflurane is a suitable agent for neuroanesthesia in adult patients. In children, cerebrovascular carbon dioxide reactivity is maintained during hypo- and normocapnia under sevoflurane anesthesia. To determine the effects of sevoflurane on middle cerebral artery blood flow velocity (Vmca) in neurologically normal children, Vmca was measured both at different MAC values and at one MAC over a specified time period, using transcranial Doppler sonography. METHODS: Twenty-six healthy children undergoing elective urological surgery were enrolled (16 patients in part I and 10 in part II). In part I of the study anesthesia comprised sevoflurane 0.5, 1.0 and 1.5 MAC in 30% oxygen and a caudal epidural block. Once steady state had been reached at each sevoflurane MAC level, three measurements of Vmca, mean arterial pressure (MAP) and heart rate (HR) were recorded. In part II of the study patients received sevoflurane 1.0 MAC over a 90-min period, with the same variables being recorded at 15-min intervals. RESULTS: Vmca did not vary significantly at 0.5, 1.0 and 1.5 MAC sevoflurane. There was a significant decrease in MAP between 0.5 MAC and 1.0 MAC sevoflurane (P < 0.005) and also between 1.0 MAC and 1.5 MAC (P < 0.01). There was no significant change in Vmca over 90 min at 1.0 MAC sevoflurane. CONCLUSION: Sevoflurane does not significantly affect cerebral blood flow velocity in healthy children at working concentrations.     

The effects of sevoflurane and nitrous oxide on middle cerebral artery blood flow velocity and transient hyperemic response.

We studied the effects of sevoflurane, with and without nitrous oxide, on the indices of cerebral autoregulation (transient hyperemic response ratio and the strength of autoregulation) derived from the transient hyperemic response (THR) test. Twelve patients (ASA physical status I or II) aged 18-40 yr presenting for routine non-neurosurgical procedures were recruited. The middle cerebral artery blood flow velocity was continuously recorded using transcranial Doppler ultrasonography. Preinduction THR tests were performed before the patients were anesthetized with alfentanil, propofol, and vecuronium. End-tidal carbon dioxide concentration and mean arterial pressure (to within 10% with a phenylephrine infusion) were maintained at their preinduction values. THR tests were performed sequentially at the following end-tidal sevoflurane concentrations: 2.2% in oxygen, 3.4% in oxygen, 3.4% with 50% nitrous oxide in oxygen, and 2.2% with 50% nitrous oxide in oxygen. Neither 2.2% nor 3.4% sevoflurane significantly affected cerebral autoregulation. The addition of 50% nitrous oxide to the 2.2%, but not the 3.4%, concentration of sevoflurane increased middle cerebral artery blood flow velocity and decreased autoregulatory indices significantly. IMPLICATIONS: Transient hyperemic response is preserved during sevoflurane anesthesia but is significantly impaired when nitrous oxide is added to the lower concentration of sevoflurane (2.2%). These findings have implications for neurosurgical patients undergoing general anesthesia.     

Pulmonary Doppler flow velocity pattern during caudal epidural anaesthesia in children

BACKGROUND: Haemodynamic effects of caudal anaesthesia in children have not been fully investigated. In the present study, we evaluated pulmonary haemodynamics during caudal anaesthesia in otherwise healthy children using Doppler-echocardiography. METHODS: Fifteen children undergoing elective lower abdominal surgery were randomly divided into two groups: nine children received 1.5% lidocaine and six physiological saline in the caudal epidural space. General anaesthesia was slowly induced and maintained using nitrous oxide and sevoflurane in oxygen. An epidural catheter was inserted into the caudal epidural space. Haemodynamic data including those with echocardiography were measured before and after epidural administration of lidocaine or saline. RESULTS: Mean blood pressure, end diastolic diameter of the left ventricle, ejection fraction of the left ventricle and mean velocity circumferential fibre shortening did not change in either group following caudal epidural block. Indices of pulmonary Doppler flow velocity, including peak velocity of pulmonary flow and acceleration-to-ejection time ratio, demonstrated a significant decrease after caudal lidocaine, but not after saline. CONCLUSIONS: Our data suggest that pulmonary Doppler flow velocity changes during caudal epidural anaesthesia, probably due to an increase in the pulmonary arterial resistance.     

The effect of remifentanil on cerebral blood flow velocity in children anesthetized with propofol

BACKGROUND: Cerebrovascular stability and rapid anesthetic emergence are desirable features of a neuroanesthetic regimen. In this randomized crossover study the effect of a low-dose remifentanil infusion on cerebral blood flow velocity (CBFV) in children anesthetized with propofol was evaluated. METHODS: Twenty healthy children aged 1-6 years undergoing urological surgery were enrolled. Following face mask induction with sevoflurane, anesthesia was maintained with a standardized propofol infusion. Rocuronium was used to facilitate tracheal intubation and normothermia, and normocapnia were maintained. All children received a caudal epidural block, and a transcranial Doppler probe was placed to measure middle cerebral artery blood flow velocity (Vmca). Each patient received a remifentanil regimen of 0.5 microg x kg(-1) followed by 0.2 microg x kg(-1) x min(-1) in a predetermined order of remifentanil + propofol or propofol alone. Vmca, mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at equilibrium with and without remifentanil. RESULTS: The combination of remifentanil and propofol caused an 8.1% decrease in MAP (P = 0.0005) and an 11.8% decrease in HR (P < 0.0001) compared with propofol alone. Vmca was not different between the two groups (P = 0.4041). CONCLUSION: The addition of remifentanil to propofol anesthesia in children causes a reduction in MAP and HR without affecting CBFV. This may imply that cerebral blood pressure autoregulation is preserved in children under propofol and remifentanil anesthesia.     

Doppler evaluation of erectile dysfunction - part 2

Doppler evaluation in erectile dysfunction (ED) has a significant role in determining the cause of ED. The advantages of penile Doppler and pharmacologic duplex ultrasonography include objective, minimally invasive evaluation of penile hemodynamics at a relatively low cost. Arteriogenic ED may be secondary to peripheral vascular disease and diabetes, or may be seen in association with coronary artery disease. Various parameters, such as diameter of the cavernosal artery, peak systolic flow velocity, degree of arterial dilatation and acceleration time, have been suggested for the diagnosis of arteriogenic ED, but peak systolic flow velocity is the most accurate indicator of arterial disease. This second part of the review article describes the various causes of ED and the interpretation and evaluation of color flow Doppler examination in ED.     

Systemic, but not pulmonary, hemodynamics are depressed during combined high thoraco-cervical epidural and general anesthesia in dogs

PURPOSE: An epidural block is frequently combined with general anesthesia. Both systemic and pulmonary hemodynamics may be affected by high epidural anesthesia and the combined general anesthetic. These effects were investigated in a canine model. METHODS: Systemic and pulmonary hemodynamics during a combined high thoraco-cervical epidural and general anesthesia were studied in dogs; the animals were anesthetized with propofol, 10 mg.kg(-1).hr(-1), or 2% sevoflurane, and then 1% mepivacaine, 5 mL, was injected epidurally between T1 and T2. Cardiac output (CO), pulmonary capillary wedge pressure (PCWP), pulmonary arterial pressure (PAP), mean arterial pressure (MAP), central venous pressure (CVP), electrocardiogram, and arterial and mixed venous gases were monitored for over 90 min after epidural mepivacaine. The interval between sevoflurane and propofol studies was two hours. RESULTS: Baseline measurement of MAP with sevoflurane anesthesia was significantly lower (P < 0.05-0.01) at every time point than with propofol anesthesia. After epidural mepivacaine (C1)-T7/8 blockade), MAP (P < 0.05-0.01), CO (P < 0.05-0.01), and heart rate (P < 0.05-0.01) decreased significantly during both propofol and sevoflurane anesthesia. In the sevoflurane group, stroke volume decreased significantly (P < 0.05-0.01) but recovered; however, MAP (P < 0.01) and CO (P < 0.05) did not recover 90 min after the injection. Mean CVP and systemic vascular resistance were not altered. There were no changes in mean PAP, mean PCWP, and pulmonary vascular resistance. CONCLUSION: A combined high thoracic/general anesthesia depressed systemic hemodynamics, whereas the pulmonary circulation was not affected. The extent of the depression varied with the general anesthetics used, sevoflurane and propofol.     

Preoperative caudal block prevents emergence agitation in children following sevoflurane anesthesia

BACKGROUND: The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain-free procedures, pain is still regarded as a major contributing factor. METHODS: In a prospective, randomized, double-blind study, we enrolled 48 premedicated and calm 2-6-year-old children undergoing inguinal hernia repair. We assigned children to one of two groups: children assigned to the caudal group (n = 24) received a caudal block to supplement sevoflurane, while children assigned to the fentanyl group (n = 24) received a bolus injection of 1 microg kg(-1) intravenous fentanyl before skin incision to supplement sevoflurane. In the post anesthesia care unit, all children were received by their parent, and the incidence of emergence agitation and pain scores, as well as hemodynamic changes, were compared in both groups. RESULTS: Forty-four children completed the study. In the fentanyl group, 59% of the children were agitated following emergence from anesthesia as compared to 4.5% in the caudal group (P < 0.001). Also, pain scores, mean values of heart rate and blood pressure as well as morphine requirement were significantly higher in the post anesthesia care unit in the fentanyl group compared to the caudal group. CONCLUSION: Our results show that in children undergoing inguinal hernia repair, pain control with a preoperative caudal block as compared to intraoperative intravenous fentanyl significantly reduces the incidence of emergence agitation and pain scores following sevoflurane anesthesia.     

布比卡因混合肾上腺素骶管阻滞对全麻新生儿血液动力学的影响

目的 评价布比卡因混合肾上腺素骶管阻滞对全麻新生儿血液动力学的影响.方法 择期或限期行腹部或会阴部手术的足月新生儿30例,性别不限,ASA Ⅰ或Ⅱ级,出生体重≥2 500 g,日龄≤28 d,随机分为3组(n=10):全麻组(A组)、全麻+骶管阻滞(0.2%布比卡因1.25 ml/kg)组(AP组)和全麻+骶管阻滞(0.2%布比卡因混合1:200 000肾上腺素,1.25 ml/kg)组(AE组).分别于骶管阻滞前5 min(T1)及骶管阻滞后5、10、15 min(T2～4)时采用超声心动图仪监测心率、每搏量、心输出量,记录平均动脉压、收缩压、舒张压,计算全身血管阻力.结果 与TI时比较,A组T4时心率减慢,AP组T2～4时心率减慢,AP组T4时心输出量减少,AE组T4时舒张压降低(P<0.05或0.01);各组间血液动力学指标差异均无统计学意义(P>0.05).结论 单独应用布比卡因或混合肾上腺素行骶管阻滞对全麻新生儿血液动力学无明显影响.     

彩色多普勒超声诊断2型糖尿病患者下肢动脉病变

目的分析彩色多普勒超声用于诊断2型糖尿病患者下肢动脉病变的价值。方法对800例2型糖尿病患者的3组下肢动脉：胫前动脉（ATA）、胫后动脉（PTA）和足背动脉（DPA）行彩色多普勒超声检查,从管径、斑块及血流动力学方面进行比较。结果糖尿病患者下肢动脉出现斑块最多、狭窄最严重的是ATA远心端和DPA,PTA斑块相对较少,狭窄较轻。糖尿病包括糖尿病足双侧下肢动脉在管径、管腔最大狭窄率及血流动力学方面差异无统计学意义,病变程度相当。结论彩色多普勒超声在诊断糖尿病下肢动脉病变中具有重要价值,有助于了解血管狭窄程度及血流动力学方面的信息,指导临床治疗。     

Pulsed color-flow Doppler analysis of arterial deficiency in idiopathic clubfoot

This prospective study used pulsed color-flow Doppler sonography to determine differences in the presence and direction of flow through the dorsalis pedis, posterior tibial, and peroneal arteries in a group of children with clubfoot and a comparison group of controls. There was a statistically significant difference in the prevalence of deficient (absent or retrograde flow) dorsalis pedis arteries in children with clubfoot (45%) compared with controls (8%). This indicates that there is an association between some clubfeet and deficiency of the dorsalis pedis artery. There was a trend toward difference in the prevalence of deficiency of the dorsalis pedis artery in the clubfeet that required surgery (54%) compared with those that did not (20%), suggesting that dorsalis pedis artery deficiency may be more prevalent among clubfeet with greater deformity.     

Cross-sectional internal diameters of radial, thoracodorsal, and dorsalis pedis arteries in children: relationship to subject sex, age, and body size

The purpose of this study was to determine the average diameter of the radial, thoracodorsal, and dorsalis pedis arteries in a pediatric population and to evaluate the relationship of these measurements to the subject's age, sex, height, weight, and body mass index (BMI). The internal diameters of the radial, thoracodorsal, and dorsalis pedis arteries were non-invasively studied in 45 normotensive, presumed normal children of various ages (4 to 14 years) with the use of a Doppler system. The average diameters of the radial, thoracodorsal, and dorsalis pedis arteries in females and males were as follows: radial artery 1.39 (SD +/- 0.18) mm and 1.57 (SD +/- 0.18) mm; thoracodorsal artery 1.27 (SD +/- 0.11) mm and 1.36 (SD +/- 0.2) mm; and dorsalis pedis artery 1.22 (SD +/- 0.08) mm and 1.34 (SD +/- 0.12) mm. These were correlated with the age, height, weight, and BMI. Gender had a strong influence on the diameter of these arteries. In a linear regression model, weight was found to be statistically the best independent variable for predicting radial and dorsalis pedis diameters, whereas age was the best predictor for the diameter of the thoracodorsal artery. The diameters of these three arteries in an age group of 4 to 14 years ranged between 1 to 2 mm. The age and weight of the children predicted the diameters of the peripheral arteries.     

The Impact of Systemic Vasoconstrictors on the Cerebral Circulation of Anesthetized Patients

Background: The effect of vasoconstrictors on intracerebral hemodynamics in anesthetized patients is controversial. The influence of phenylephrine and norepinephrine on the cerebral circulation was investigated in isoflurane- or propofol-anesthetized patients using transcranial Doppler ultrasonography.

Methods: Forty patients were randomly assigned to have vasoconstrictor tests with norepinephrine or phenylephrine during either isoflurane or propofol anesthesia. Blood flow velocities were simultaneously measured in the middle cerebral artery and ipsilateral extracranial internal carotid artery. Baseline recordings were done during stable anesthesia in a supine position (test 0). A second series of measurements were performed after norepinephrine or phenylephrine had increased mean arterial blood pressure by about 20% (test 1). With maintained norepinephrine or phenylephrine infusion, a final series of results were obtained after the increased mean arterial blood pressure was counteracted by a slightly head-up patient position (test 2).

Results: Both vasoconstrictors significantly increased mean flow velocities in the middle cerebral artery (norepinephrine: 43 +/- 11 cm/s to 49 +/- 11 cm/s; phenylephrine: 43 +/- 8 cm/s to 48 +/- 9 cm/s; +/- SD) and internal carotid artery (norepinephrine: 27 +/- 7 cm/s to 31 +/- 8 cm/s; phenylephrine: 27 +/- 9 cm/s to 31 +/- 10 cm/s) in the isoflurane-but not in the propofol-anesthetized patients. In the head-up position, only small and insignificant flow velocity changes were observed in both cerebral arteries independent of the vasoconstrictor or background anesthetic.     

Dynamic cerebral blood flow autoregulation during sevoflurane anesthesia and TIVA

BACKGROUND: Dynamic cerebral blood flow autoregulation during sevoflurane anesthesia and total intravenous anesthesia (TIVA) is unclear. We examined the cerebral circulation autoregulation during anesthesia by sevoflurane or TIVA. METHODS: We measured mean blood pressure (MBP) and blood flow velocity of the middle cerebral artery by a transcranial Doppler ultrasonography before and during anesthesia using sevoflurane (volatile induction and maintenance of anesthesia (VIMA) group) and using propofol and fentanyl (TIVA group), and the relationship between changes in MBP and cerebral blood flow velocity was evaluated using the method of transfer function analysis. We calculated transfer gain and coherence by cross-spectrum from autospectra of MBP and cerebral blood flow velocity. RESULTS: Transfer gain during anesthesia by TIVA in the low frequency range and high frequency range was near 1 cm.sec-1.mmHg-1. It was about equal to the value of transfer gain before anesthesia. But transfer gain during anesthesia by VIMA was above 2 cm.sec-1.mmHg-1. CONCLUSION: These results suggest that TIVA by propofol and fentanyl maintains the dynamic autoregulation of cerebral blood flow, but sevoflurane impairs the autoregulation.     

Effects of Sevoflurane with and without Nitrous Oxide on Human Cerebral Circulation: Transcranial Doppler Study

Background: This study was designed to evaluate the effects of sevoflurane with and without nitrous oxide on human middle cerebral artery (MCA) flow velocity, cerebrovascular carbon dioxide reactivity, and autoregulation compared with the awake state using transcranial Doppler ultrasonography.

Methods: In 14 patients, the time-mean middle cerebral artery flow velocity (Vmca) was measured when the end-tidal carbon dioxide level was approximately 30, 40, and 50 mmHg under the following conditions: (1) awake; (2) with 2% (1.2 MAC) sevoflurane; and (3) with 1.2 MAC sevoflurane-60% nitrous oxide. In six other patients, the cerebrovascular autoregulation during anesthesia was determined using intravenous phenylephrine to increase blood pressure.

Results: Sevoflurane (1.2 MAC) significantly decreased Vmca compared with the awake value at each level of end-tidal carbon dioxide, whereas 1.2 MAC sevoflurane-60% nitrous oxide did not exert significant influence. The Vmca in normocapnic patients decreased from 69 cm/s to 55 cm/s with 1.2 MAC sevoflurane and then increased to 70 cm/s when nitrous oxide was added. Sevoflurane (1.2 MAC) with and without 60% nitrous oxide had a negligible effect on cerebrovascular carbon dioxide reactivity. A phenylephrine-induced increase of mean arterial pressure did not influence Vmca during anesthesia.     

The effects of propofol or sevoflurane on the estimated cerebral perfusion pressure and zero flow pressure

The zero flow pressure (ZFP) is the pressure at which blood flow ceases through a vascular bed. Using transcranial Doppler ultrasonography, we investigated the effects of propofol or sevoflurane on the estimated cerebral perfusion pressure (eCPP) and ZFP in the cerebral circulation. Twenty-three healthy patients undergoing nonneurosurgical procedures under general anesthesia were studied. After induction of anesthesia using propofol, the anesthesia was maintained with either propofol infusion (n = 13) or sevoflurane (n = 10). Middle cerebral artery flow velocity, noninvasive arterial blood pressure, and end-tidal carbon dioxide partial pressure were recorded awake as a baseline, and during steady-state anesthesia at normocapnia (baseline end-tidal carbon dioxide partial pressure) and hypocapnia (1 kPa below baseline). The eCPP and ZFP were calculated using an established formula. The mean arterial blood pressure decreased in both groups. The eCPP decreased significantly in the propofol group (median, from 58 to 41 mm Hg) but not in the sevoflurane group (from 60 to 62 mm Hg). Correspondingly, ZFP increased significantly in the propofol group (from 25 to 33 mm Hg) and it decreased significantly in the sevoflurane group (from 27 to 7 mm Hg). Hypocapnia did not change eCPP or ZFP in the propofol group, but it significantly decreased eCPP and increased ZFP in the sevoflurane group.     

小儿肱动脉与足背动脉血压值的对比研究

目的探讨小儿肱动脉与足背动脉血压值的差异性及其内在规律。方法随机抽取生长发育正常的8~11岁学生共120名,采用自身配对方法,测量其平卧、坐位时的足背动脉与平卧时的肱动脉血压并进行分析比较。结果平卧时小儿足背动脉收缩压显著低于肱动脉收缩压(P<0.01),而其舒张压比较,差异无显著性意义(P>0.05);坐位时,足背动脉收缩压、舒张压均显著高于平卧位肱动脉血压(均P<0.01);足背动脉血压与肱动脉血压呈正相关并存在线性依存关系。结论小儿足背动脉测压简便易行,可根据回归方程推算肱动脉血压。     

Effect of caudal block on sevoflurane requirement for lower limb surgery in children with cerebral palsy

Background: Caudal block is a widely used technique for providing perioperative pain management in children. In this randomized double‐blinded study, we evaluated the effects of preoperative caudal block on sevoflurane requirements in children with cerebral palsy (CP) undergoing lower limb surgery while bispectral index (BIS) values were maintained between 45 and 55. Methods: 52 children undergoing Achilles‐tendon lengthening were randomized to receive combined general–caudal anesthesia (caudal group, n = 27) or general anesthesia alone (control group, n = 25). Caudal block was performed with a single dose of 0.7 ml·kg^?1 of 1.0% lidocaine containing epinephrine at 5 μg·ml^?1. The control group received no preoperative caudal block. The endtidal sevoflurane concentrations (ET_sev) were adjusted every minute to maintain the BIS values between 45 and 55. Results: The ET_sev required to maintain the BIS values were not significantly different between the control and caudal groups after induction of anesthesia [2.1 (0.2) vs 2.2 (0.4); P = 0.773]. However, significantly higher ET_sev was observed in the control group before surgical incision [2.0 (0.2) vs 1.8 (0.3); P = 0.013] and during the first 20 min after surgical incision [2.2 (0.3) vs 1.4 (0.3); P < 0.001]. There was no significant difference in BIS values between the control and caudal groups throughout the study period (P > 0.05). In the caudal group, the caudal block was successful in 25 of 27 (92.6%) patients. Conclusions: Caudal block effectively reduced sevoflurane requirements by 36% compared to general anesthesia alone in children with CP undergoing lower limb surgery while BIS values were maintained between 45 and 55.     

The effect of nitrous oxide on cerebral blood flow velocity in children anaesthetised with desflurane

The aim of this study was to determine the effect of nitrous oxide on cerebral blood flow velocity in children anaesthetised with desflurane. Eighteen healthy children scheduled for elective surgery were enrolled into the study. Anaesthesia was induced using sevoflurane, and a caudal block was performed following tracheal intubation. Anaesthesia was maintained with 1 age-adjusted MAC desflurane. A transcranial Doppler probe was used to measure middle cerebral artery blood flow velocity. Each patient was randomised to receive a sequence of either air/nitrous oxide/air or nitrous oxide/air/nitrous oxide in 30% oxygen. Fifteen minutes after each change in the nitrous oxide concentration, three measurements of cerebral blood flow velocity, blood pressure and heart rate were recorded. Neither the addition nor removal of nitrous oxide caused any significant changes in middle cerebral artery blood flow velocity, heart rate or blood pressure. This may be due to a more potent cerebral vasodilatory effect of desflurane in children.     

The hemodynamic effects of pediatric caudal anesthesia assessed by esophageal Doppler

Pediatric caudal anesthesia is an effective method with an infrequent complication rate. However, little is known about its cardiovascular consequences. Transesophageal Doppler, a noninvasive method, provides the opportunity for a reappraisal of the hemodynamic effects of this technique. After parental informed consent, we studied 10 children aged 2 mo to 5 yr who were scheduled for lower abdominal surgery. General anesthesia was induced using sevoflurane and was followed by the insertion of a transesophageal Doppler probe. Caudal anesthesia was performed using 1 mL/kg of 0.25% bupivacaine with 1/200,000 epinephrine. Hemodynamic variables were collected before and after caudal anesthesia. No complications arose during insertion of the probe. The mean time between the two sets of measurements was 15 min. Heart rate, systolic, diastolic, and mean arterial blood pressures were not modified by caudal anesthesia. Descending aortic blood flow increased significantly from 1.14 to 1.92 L/min. (P = 0.0002). Aortic ejection volume increased from 8.5 to 14.5 mL (P = 0.0002). Aortic vascular resistances decreased from 6279 to 3901 dynes. s(-1) x m(-5) (P = 0.005). Caudal anesthesia did not affect heart rate and mean arterial blood pressure but induced a significant increase in descending aortic blood flow. IMPLICATIONS: Although pediatric caudal anesthesia does not alter heart rate nor arterial blood pressure, significant changes occur in regional blood flow distribution. Descending aortic blood flow increases significantly after caudal anesthesia, whereas lower body vascular resistances decrease.     

Spinal anesthesia with bupivacaine decreases cerebral blood flow in former preterm infants

Spinal anesthesia is commonly used in former preterm infants (FPI). In these patients, hypotension induced by spinal anesthesia may impair cerebral blood flow. We measured cerebral blood flow velocity (CBFV) by transcranial Doppler ultrasound to assess the effect of hypotension induced by spinal anesthesia on cerebral hemodynamics. Twelve FPI scheduled for inguinal hernia repair were operated under spinal anesthesia using 1 mg/kg isobaric 0.5% bupivacaine. Systolic, diastolic, and mean middle cerebral artery CBFV were measured at 5 min before and 5 min and 10 min after spinal anesthesia using a transcranial pulsed Doppler ultrasonography. Arterial blood pressure and heart rate were recorded simultaneously. Cerebral arteries resistance index (RI) was calculated as RI = (peak systolic CBFV - end-diastolic CBFV)/peak systolic CBFV. Diastolic CBFV decreased significantly from 30.0 +/- 11.1 cm/s to 20.1 +/- 8.4 cm/s at 5 min and to 20.1 +/- 7.0 cm/s at 10 min. RI increased significantly from 0.7 +/- 0.1 to 0.8 +/- 0.1 at 5 min and 10 min. Systolic, diastolic, and mean arterial blood pressures decreased significantly at the same time intervals. We suggest that in FPI, spinal anesthesia induces a decrease in cerebral blood flow related to changes in arterial blood pressure. Whether these changes have deleterious consequences remains to be determined. IMPLICATIONS: In former preterm infants having spinal anesthesia with bupivacaine, a decrease in cerebral blood flow velocity is displayed by middle cerebral artery transcranial Doppler examination.