Changes in maternal middle cerebral artery blood flow velocity associated with general anesthesia in severe preeclampsia

In women with severe preeclampsia, significant increases in mean arterial pressures (MAP) are common after rapid induction of general anesthesia (GA) and tracheal intubation. The objectives of this prospective study were to assess the effects of the rapid induction-intubation technique on middle cerebral artery (MCA) flow velocity in severe preeclampsia and to examine the correlation between mean MCA flow velocity (Vm) and MAP. Eight women with severe preeclampsia (study group) and six normotensive women at term (control group) scheduled to undergo cesarean section under GA were studied. Before induction, patients in the study group received i.v. labetalol in divided doses to lower diastolic pressures to <100 mm Hg. Anesthesia was induced with pentothal 4-5 mg/kg, followed by succinylcholine 1.5 mg/kg to facilitate tracheal intubation. A transcranial Doppler was used to measure Vm. Both Vm and MAP were recorded before induction and every minute for 6 min after intubation. In the study group, after the administration of labetalol, MAP decreased from 129 +/- 9 to 113 +/- 9 mm Hg (P < 0.05), and Vm decreased from 59 +/- 11 to 54 +/- 10 cm/s (P < 0.05). After intubation, MAP increased from 113 +/- 9 to 134 +/- 5 mm Hg (P < 0.001), and Vm increased from 54 +/- 10 to 70 +/- 10 cm/s (P < 0.001). In the control group, while MAP increased significantly from 89 +/- 6 to 96 +/- 4 mm Hg (P < 0.05) after intubation, the concurrent increase in Vm from 49 +/- 5 to 54 +/- 7 cm/s was not significant. There was a significant positive pooled correlation between Vm and MAP (r = 0.5, P < 0.0006) in the study group but not in the control group (r = 0.24). After induction and intubation, both Vm and MAP values were significantly increased in the study group patients at all observation points compared with the control group patients. The findings indicate that Vm increases significantly after rapid-sequence induction of GA and tracheal intubation in women with severe preeclampsia, and there seems to be a direct relationship between MAP and Vm. Implications: In women with severe preeclampsia, rapid-sequence induction of general anesthesia and tracheal intubation can cause severe hypertension. Our results indicate that the increase in blood pressure is associated with a significant increase in maternal cerebral blood flow velocity and that there is a significant correlation between these two variables.     

Effect of altering cerebrospinal fluid pressure on spinal cord blood flow

The outcome of patients with cholesterolosis was compared with that of those with chronic cholecystitis operated on for chronic acalculous biliary pain. A total of 55 patients with acalculous biliary pain with a median symptom duration of 24 (range 6-120) months were investigated by dynamic cholescintigraphy and followed for a median of 24 (range 12-60) months. Thirty-five patients underwent cholecystectomy, of whom 22 had a low gallbladder ejection fraction (under 35 per cent), with symptomatic improvement in 21 of these (P < 0.01). All four patients with a normal ejection fraction (35-50 per cent) improved after cholecystectomy but only four of nine with a high ejection fraction (over 50 per cent) did so. Results of histological examination were available in 32 patients and revealed cholesterolosis in 20. A low ejection fraction was found in 16 patients with cholesterolosis, of whom 15 showed symptomatic improvement after cholecystectomy; the other four patients had a high fraction and all improved after cholecystectomy. Overall, symptoms in 19 of 20 patients with cholesterolosis improved after cholecystectomy compared with only seven of 12 with chronic cholecystitis (P = 0.03).     

Changes of upper gastrointestinal blood flow after hemorrhage in rabbits

The effect of hemorrhage and blood transfusion on the regional blood flow of the upper gastrointestinal tract was measured with radioactive microspheres in a rabbit shock model. Fifteen minutes after hemorrhage, mucosal blood flow in the esophagus, corpus, and antrum and total blood flow in the duodenum decreased drastically. The persistent reduction of mucosal blood flow continued until 60 minutes after hemorrhage. In spite of these distribution patterns of mucosal blood flow during hemorrhage, no macroscopic change was seen in any part of the gastrointestinal mucosa. One hour after blood reinfusion, the mucosal blood flow in the corpus was increased markedly, and innumerable hemorrhagic erosions appeared in this region. It may be that the striking increase of mucosal blood flow due to blood transfusion caused bleeding from the disrupted mucosa of the corpus. At this time the impaired flow in the esophagus, antrum, and duodenum tended to be improved already. Six hours after blood reinfusion, the bleeding from the mucosal foci in the corpus ceased and the mucosal blood flow returned to almost normal. Thus the higher susceptibility of the corpus to hemorrhagic shock may be due to the greater degree of rapid increase of mucosal blood flow occurring in this portion alone after blood transfusion as well as to its higher vulnerability to ischemia in the hemorrhagic period. The flow patterns in the muscular layer almost paralleled those in the mucosal layer during hemorrhage and blood transfusion.     

Regional spinal cord blood flow in rats after severe cord trauma

Spinal cord blood flow (SCBF) was measured in 12 albino rats following acute cord injury produced by the extradural clip compression technique. Severe injury was produced with the clip compressing the cord with a force of 180 gm for 5 minutes, an injury previously shown to produce a severe functional deficit. Regional SCBF was measured 15 minutes, 2 hours, and 24 hours after injury by the 14C-antipyrine autoradiographic technique and a scanning microscope photometer. At 15 minutes and 2 hours, white and gray matter blood flow was severely diminished, and, at 24 hours, there was only minimal improvement. Focal decreases in blood flow were seen in white and gray matter for a considerable distance proximal and distal to the site of cord trauma. Thus, it has been confirmed in this model that severe cord compression injury produces severe posttraumatic ischemia in the cord which lasts for at least 24 hours.     

Changes in physical strain and physical capacity in men with spinal cord injuries

To determine longitudinal changes in physical capacity and physical strain during activities of daily living (ADL), 37 men with spinal cord injuries (C4/5-L5) performed an exercise test and various ADL on two occasions (T1 and T2; interval 34.5 +/- 1.5 months). Parameters of physical capacity were aerobic power (VO(2peak)) and maximal power output (PO(max)). Physical strain was estimated by the heart rate response relative to the heart rate reserve. VO(2peak) at T2 (1.75 +/- 0.55 1*min(1)) did not significantly differ from that at T1 (1.67 + 0.47 1*min(-1)). Absolute PO max improved (P < 0.05) from 64.9 +/- 25.9 (T1) to 71.7 +/- 27.2 W (T2), whereas relative PO(max) did not change. Activity level, time since injury, change in body mass, and occurrence of rehospitalization were the most important predictors of changes in physical capacity. Changes in relative VO(2peak) were related (P < 0.05) to changes in strain during transfers to the shower wheelchair (r = -0.39) and shower seat (r = -0.46), and during the curb ascent (r = -0.47). In conclusion, the hypothesized decline in physical capacity did not occur over the 3-yr period. Maintenance of physical capacity, which may in part be achieved through sport participation and improved medical care, together with avoidance of excessive body mass, may be useful to prevent high levels of strain during ADL.     

Changes in blood chemistries following prolonged enflurane anesthesia

In an effort to identify further the structural requirements for central dopamine receptor agonists, some monohydroxyl analogs of the known agonist 5,6-dihydroxy-2-dipropylamino-1,2,3,4-tetrahydronaphthalene were synthesized. They were examined for production of emesis in dogs and stereotyped behavior in rats. The most potent was 5-hydroxy-2-dipropylamino-1,2,3,4-tetrahydronaphthalene, which was more potent than apomorphine but less so than the dihydroxyl analog. The two enantiomers of the monohydroxyl analog were synthesized by conventional methods from an optically active intermediate, 2-benzylamino-5-methoxy-1,2,3,4-tetrahydronaphthalene. The resolution of this amine was performed with the aid of mandelic acid. Dopaminergic activity was found to be confined to the levo enantiomer. Requirements for both substitution and chirality in the tetralines were found to correspond closely to those known for the dopaminergic aporphines.     

Spinal cord blood flow and evoked potential responses after treatment with nimodipine or methylprednisolone in spinal cord-injured rats

This study examined the effect of nimodipine or methylprednisolone on spinal cord blood flow (SCBF) and electrophysiological function after spinal cord injury in rats. Three groups of male rats (n = 10 per group) were injured by compression of the cord at T1 for 1 minute with a 52-g clip. The hydrogen clearance technique was used to measure SCBF at the T1 segment. Motor and somatosensory evoked potentials were recorded. SCBF and evoked potentials were measured before injury and again at approximately 1 and 2.5 hours after injury. The methylprednisolone group received a bolus of methylprednisolone (30 mg/kg) at 5 minutes after injury and then at 15 minutes after injury, the group received an infusion of methylprednisolone at 5.4 mg/kg per hour. The nimodipine group received placebo at 5 minutes and then received an infusion of nimodipine at 0.02 mg/kg per hour at 15 minutes. The placebo group received placebo at both times. Physiological parameters were closely monitored and maintained within the normal range. Albumin was administered after injury to maintain mean arterial blood pressure at or above 80 mm Hg. The infusions were continued for approximately 3 hours after spinal cord injury. SCBF was not significantly different between the experimental groups at either 1 or 2.5 hours postinjury (P = 0.16 and 0.71, respectively), and evoked potential responses did not return in any rat at any time after injury. Thus, this experiment failed to demonstrate an improvement in SCBF or electrophysiological function with either drug.(ABSTRACT TRUNCATED AT 250 WORDS)     

Emboli observed with use of transesophageal echocardiography immediately after tourniquet release during total knee arthroplasty with cement

We analyzed the genetic defect in a 67-year-old Japanese male patient with apolipoprotein (apo) A-I and high density lipoprotein (HDL) deficiencies, corneal opacities, and coronary artery disease. The plasma concentrations of apoA-I and HDL cholesterol were 2.9 to 7.3 mg/dL and 0.08 to 0.19 mmol/L, respectively. The lecithin:cholesterol acyltransferase (LCAT) activity and cholesterol esterification rate were <40% of normal control values. LCAT mass was 550% of normal control. Sequence analysis of polymerase chain reaction-amplified DNA of the proband's apoA-I gene showed a homozygous T-to-A transition resulting in the substitution of Val 156 with Glu (apoA-I Oita). Direct sequencing of samples obtained from other family members showed that the brother was homozygous, whereas the son was a heterozygous carrier of apoA-I Oita. The heterozygote for apo A-I Oita showed nearly 60% of normal apoA-I and normal HDL cholesterol levels. In vivo turnover studies in rabbits demonstrated that the variant apoA-I was rapidly cleared from plasma compared with normal human apoA-I. Our data suggest that the Val156Glu substitution is associated with apoA-I and HDL deficiency, partial LCAT deficiency, and corneal opacities and that Val156 of apoA-I may play an important role in apoA-I function.     

Experiences with Ketalar anesthesia in gynecological and obstetrical operations

The authors' experience with Ketalar anaesthesia applied in 483 cases has been described. The effect of the narcotic on the cardiovascular system, respiration and acid-base household is analysed in details. As stated by the authors, the narcotic is well applicable in obstetrical and gynecological small operations. By appropriate preparation the occurence of side effects can be reduced. With Shirodkar operations increase of the uterine tonus can be prevented by protective premedication. Ketalar is not recommended for the introduction of anaesthesia in cases of Caesarean section as it may increase the incidence of neonatal asphyxia.     

Changes in vitamin E concentration after surgery and anesthesia

The aim of this randomized study was to examine changes in vitamin E concentration in female subjects (age 30-60, ASA I) after cholecystectomy and halothane (N = 16) or isoflurane (N = 16) anaesthesia. Vitamin E concentration was measured two days before, and then one, five and twenty-four hours and four days after surgery. High-pressure liquid chromatography was used for its determination. Simultaneously activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT) were determined. Statistical analysis: ANOVA, Tukay HSD test. The research has been accepted by the Drugs Committee of the Karlovac County Hospital. Preoperative vitamin E concentrations in the halothane group were 8.69 +/- 2.35 micrograms/L, median 8.67 micrograms/L and in the isoflurane group 9.43 +/- 2.4 micrograms/L, median 9.08 micrograms/L. Statistically lower vitamin E concentrations compared with preoperative values were noted one hour (P < 0.05), 5 hours (P < 0.01), 24 hours (P < 0.01), as well as 4 days (P < 0.01) after the operation. The lowest vitamin E concentrations were noted 24 hours after the operation with statistically insignificantly higher values in the isoflurane group (halothane group 5.98 +/- 2.08 micrograms/L, isoflurane group 6.58 +/- 1.51 micrograms/L). Analyzing enzyme (ALT, AST and GGT) pre- and postoperative values, no statistically significant differences between the investigated groups and during the time were observed. Statistically significant differences were found between individual measurement times, with no statistical significance of the differences between the halothane and isoflurane groups. It seems that neither the difference in halothane and isoflurane biotransformation nor their distinct effect on perfusion of some organs are the determining factors in post-operative changes in vitamin E concentration.     

Changes of peripheral blood flow in patients with cancer of the lungs, esophagus and cardia under the effect of anesthesia and surgery

The authors report the data on changes in peripheral circulation, depending on the kind of anesthesia, the amount of operative blood loss, alterations in circulating blood volume and localization of tumor in patients with cancer of the lung, esophagus and cardia. Totally, 35 patients (15--lung cancer, 10--esophageal cancer, 10--cancer of the cardia) were explored. In 25 cases fluothane was used as the main anesthetic, in 10--neuroleptanalgesia. The state of peripheral circulation was estimated by the period semielimination of radioactive xenon-133 from the muscle depot. It was found that alterations in peripheral circulation were not dependent on tumor localization, the use of fluothane and neuroleptanalgesia is associated with similar changes in peripheral blood flow and, finely, an increased loss of blood results in more pronounced alterations in peripheral circulation.     

Changes in the serum lipoprotein spectrum after gynecologic operations especially after castration

The authors have studied the changes of serum lipoproteins spectrum after various operations in 50 women. They found different changes that can be explicated with operation stress, bleeding or fasting. After the interventions with bilateral ovarectomy they found a dyslipoproteinema with an early and rapid increase of low density lipoproteins.     

Alveolar oxygen uptake and blood flow dynamics in knee extension ergometry

The relationship was studied between the increase in oxygen uptake (VO2) measured breath-by-breath at the mouth, and the increase in femoral artery blood flow measured continuously with pulsed and echo Doppler methods. Five men exercised at 50 W on a knee extension ergometer in both the supine and the upright posture. The kinetics of the responses were determined by curve fitting to obtain the mean response time (MRT = 63% of the time required to achieve steady state). In the upright position, the increase in blood flow (MRT = 12.4 +/- 9.4 s, mean +/- SD) was faster than the increase in VO2 (29.6 +/- 9.3 s). Likewise in the supine position, blood flow increased more rapidly (25.1 +/- 9.7 s vs. 36.7 +/- 9.6 s). It should be noted that the increase in blood flow appeared to be faster than VO2, yet when blood flow adapted more slowly in the supine posture, it had an impact on the adaptation of VO2. This suggests that blood flow might have important effects on metabolism at the onset of submaximal exercise.     

Effects of morphine and halothane anesthesia on coronary blood flow

This study was undertaken to determine the relative effects of morphine and halothane anesthesia on coronary blood flow. Right heart bypass was instituted in 20 dogs by draining the vena cava blood into a cardiotomy reservoir and returning it to the main pulmonary artery. Coronary sinus drainage was measured by a right ventricular cannula. Group I (10 dogs) was sequentially given 0.5, 1, 1.5, 2.0, and 2.5% halothane. Group II (10 dogs) was given 1, 2, 3, 4, and 5 mg per kilogram of morphine intravenously. Arterial pressure, coronary sinus blood flow, cardiac output, arterial pH, PCO2, and PO2 were determined and repeated at each dose level of anesthesia and compared to the control values. Morphine significantly increased coronary flow at 3, 4, and 5 mg/kg without pressure adjustment and at 2 mg/kg after pressure adjustment. Coronary flow with halothane was unchanged from control values except for a decrease at 2.5%. Coronary flow was significantly greater with 3, 4, and 5 mg/kg of morphine than with 1.0 and 1.5% halothane.     

Changes in muscle blood flow distribution during hyperthermia

Blood flow is a critical parameter for obtaining satisfactory temperature distributions during clinical hyperthermia. This study examines the changes in blood flow distribution in normal porcine skeletal muscle before, during and after a period of regional microwave hyperthermia. The baseline blood flow distribution during general anaesthesia and after the insertion of the thermal probes was established independently in order to isolate the changes due to hyperthermia. General anaesthesia alone and thermocouple insertion during anesthesia had no significant effect on the muscle blood flow distribution. Regional microwave heating generated a non-uniform blood flow distribution which was a function of the tissue temperature distribution. Blood flow was greater in those tissues samples in which higher temperatures were recorded and less in those sampled further from the applicators peak SAR (Specific Absorption Rate). The increase in blood flow appears to be primarily a local phenomenon. Although muscle blood flow may be considered to be uniform prior to heating, this does not hold during hyperthermia treatment. Therefore, the non-uniform nature of the blood distribution during heating should be incorporated into any practical bioheat transfer model.     

Changes of venous blood flow velocity waveforms in fetuses with supraventricular tachycardia

Studies in the fetal lamb have shown that atrial pacing beyond a rate of 300-320 beats/min may be associated with dramatic changes of venous blood velocity waveforms, an increase of venous pressure by up to 75%, hydrops, polyhydramnios and placental edema. The aim of our study was to determine the 'critical' heart rate frequency in the human fetus. In 11 fetuses (five with and six without hydrops) with supraventricular tachycardia, pulsed wave Doppler analysis of flow velocity waveforms of the inferior vena cava, the ductus venosus and the left hepatic vein were performed before and after drug treatment. In ten cases cardioversion was achieved by in utero antiarrhythmic drug therapy; in one case treated with digoxin and flecainide the supraventricular tachycardia was decreased to 160-190 beats/min with disappearance of hydrops. Before intrauterine treatment of supraventricular tachycardia, pulsatile reversal of blood flow in the inferior vena cava, ductus venosus and left hepatic vein was visible, with monophasic forward flow during systole and reversed flow during diastole in ten of 11 fetuses. One fetus with supraventricular tachycardia of 195 beats/min showed a normal biphasic forward flow pattern. During drug-induced sinus rhythm, a normal biphasic forward venous blood flow pattern was shown in all ten cases. In five cases pulsatile reversal was demonstrated during a drug-induced reduction of the heart rate from 280 to 210 beats/min and a normal biphasic forward flow velocity waveform appeared during supraventricular tachycardia below 210 beats/min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Presence of epithelial cells in the medullary canal after spinal anesthesia

BACKGROUND AND AIM: Several authors have focused on a causal link between the onset of neurological complications after lumbar injections and the fact that epithelial cells may be drawn into the vertebral canal during these procedures. Complications may arise both early (cephalea, septic and aseptic meningitis) and late (epidermoid tumours). The authors aimed to evaluate whether skin fragments which are carried down by the needle during subarachnoid anesthesia may even be present in the epidural or subarachnoid space three days later and may therefore justify the onset of the above neurological syndromes. METHODS: Five adult cats under narcosis underwent subarachnoid anesthesia using disposable 22G Quincke type needles. Between 0.7 and 1 ml isobaric bupivacaine at 0.50% was injected. The presence of the motor block of the lower limbs was ascertained once the effects of general anesthesia wore off. On the third day, again under general anesthesia, cardio-respiratory arrest was provoked by intravenous injection. Samples of meninges were collected in the injection area. After fixation in a phosphate glutaraldehyde buffer, dehydration in acetone, dehydration by critical point and gold metalisation, the samples were examined using SEM. RESULTS: No epidermal cells were found on the surface of the meninges. On the other hand, a squamous epithelial cell was observed which drained inside a sectioned epidural vessel towards the systemic circulation. CONCLUSIONS: This study confirms the possibility that, after subarachnoid anesthesia using 22G Quincke needles, skin fragments may enter the spinal canal. The permanence or otherwise of the epithelial fragments on the third day depends on the size of the fragment drawn down and the efficacy of the drainage system which removes isolated epithelial cells. This phenomenon may justify the self-limiting character of cephalea and meningisms which, even if not treated, regress in a few days, as well as the scarce development of epidermoid tumours.     

The advantages of the lateral decubitus position after spinal anesthesia with hyperbaric tetracaine

Exercise-induced bronchoconstriction (EIB) is widely prevalent in asthmatic patients. Eosinophilic airway inflammation is considered to be a major factor in the pathogenesis of asthma. However, the effects of eosinophilic airway inflammation on EIB have been elucidated insufficiently. To examine the relationship between the severity of EIB and eosinophilic inflammation, sputum induction and exercise challenge were performed in 21 asthmatic patients. Significantly higher percentages of eosinophils and levels of eosinophil cationic protein (ECP) were found in induced sputum in EIB-positive asthmatics (median (range), eosinophils: 23.5 (11.0-61.0)%; ECP: 1,475 (74.8-17,701) ng x mL(-1)) than in EIB-negative asthmatics (eosinophils: 6.0 (1.0-41.5)% (p=0.006); ECP: 270.6 (10.8-7,700) ng x mL(-1) (p=0.049)). There was a significant correlation between the severity of EIB and the sputum eosinophil percentage (r=0.59, p=0.009) and the level of ECP (r=0.47, p=0.037). The area under the curve of the forced expiratory volume in one second for 30 min after exercise correlated with the percentage of eosinophils (r=0.60, p=0.008) and the level of ECP (r=0.45, p=0.04). There was no correlation between airway responsiveness to methacholine on the one hand and EIB, sputum eosinophils or ECP on the other. In conclusion, these results provide evidence that the severity of bronchoconstriction evoked by exercise is more closely related to eosinophilic airway inflammation than airway hyperresponsiveness to methacholine in asthmatic patients.