Stable plasma concentrations of unbound ropivacaine during postoperative epidural infusion for 24-72 hours in children.

BACKGROUND AND OBJECTIVES: The aim of this open, non-controlled, multi-centre study was to evaluate the pharmacokinetics and safety of a 24-72 h continuous epidural ropivacaine infusion in children aged 1-9 yr. METHODS: After induction of general anaesthesia, 29 ASA I-II children, scheduled for major surgery in dermatomes below T10 had lumbar epidural catheters placed. A bolus of ropivacaine, 2 mg kg(-1), was given over 4 min, followed immediately by an infusion of 2 mg mL(-1) ropivacaine 0.4 mg kg(-1) h(-1) for the next 24-72 h. RESULTS: Plasma concentrations of total ropivacaine (mean 0.83 and 1.06 mg L(-1) at 16-31 and 59-72 h, respectively) and alpha1-acid-glucoprotein (mean 13 and 25 micromol L(-1) at baseline and 59-72 h) increased over the course of the infusion. Plasma concentrations of unbound ropivacaine were stable throughout the epidural infusion (mean 0.021 range 0.011-0.068 and mean 0.016 range 0.009-0.023 mg L(-1) at 16-31 and 59-72 h, respectively) and were well below threshold levels associated with central nervous system toxicity in adults (0.35 mg L(-1)). Apparent unbound clearance (mean 346, range 86-555 mL min(-1) kg(-1)) showed no age-dependency. No signs of systemic toxicity or cardiovascular effects were observed. All patients received additional analgesics with morphine. CONCLUSION: Following a 24-72 h epidural infusion of ropivacaine 0.4 mg kg(-1) h(-1) in 1-9-yr-old children, the plasma concentrations of unbound ropivacaine were stable over time with no age-dependency.

Validation of a six-graded faces scale for evaluation of postoperative pain in children.

BACKGROUND: The faces pain scales are often used for self-report assessment of paediatric pain. The aim of this study was to evaluate the validity of a six-graded faces pain scale after surgery by comparing the level of agreement between the children's report of faces pain scores and experienced nurses' assessment of pain by observation of behaviour. The faces pain scores before, at and after administration of analgesics were analysed. The study was performed in two South African hospitals, one with a mainly rural population and the other with an urban population. METHODS: A total of 110 children aged 4-12 years, scheduled for inguinal surgery in the two South African hospitals, were included in the study. The anaesthetic technique was standardized. All patients received a caudal block preoperatively. Postoperative pain assessments were made every hour for 8 h after the caudal block was performed. A designated nurse assessed pain by using a four-graded descriptive scale (no, mild, moderate or severe pain) and thereafter the child reported pain by using the six-graded faces pain scale. RESULTS: A high correlation was found between the two methods of assessment (tau = 0.76, P < 0.0001). The correlation between methods was high in both hospital populations and in all age groups. The weakest correlation was found in children aged 8-12 years (tau = 0.56, P < 0.01). Significantly lower faces pain scores were found after administration of analgesics compared with pain rating before analgesics (P < 0.0001). The proportion of patients with pain scores above 2 decreased from 86% to 31% (P < 0.001). CONCLUSIONS: The findings support this six-graded faces pain scale as a useful and valid instrument for measuring pain in the postoperative period in children aged 4-12 years.

Increased incidence of postoperative nausea and vomiting without additional analgesic effects when a low dose of intravenous fentanyl is combined with a caudal block.

BACKGROUND: The use of opioids is known to increase the incidence of postoperative nausea and vomiting (PONV). In spite of this, administration of low doses of an opioid during anaesthesia is common practice, even if a regional anaesthetic technique is used. This study was designed to estimate the effects of intraoperative intravenous administration of fentanyl on PONV in paediatric daycase surgery. METHODS: PONV and pain were evaluated in 29 boys during the first 24 h after daycase penile surgery. Anaesthesia was standardized. The patients were allocated to two groups. Fentanyl 1 micro g.kg-1 i.v. or placebo was administered in a randomized, double-blind design. A caudal block with ropivacaine 2 mg.ml-1, 0.5 ml.kg-1 was performed preoperatively and topical lidocaine gel 20 mg.ml-1 was applied over the wound area immediately after surgery. RESULTS: The total incidence of PONV in hospital and at home during the first 24 h was 36% (5/14) when fentanyl was used, whereas no PONV was reported when placebo was given (P < 0.05). The median time to first administration of analgesics after the caudal block was approximately 6 h. It did not differ between groups. Intraoperative fentanyl did not result in any reduction in pain scores nor the incidence of pain. Fentanyl caused apnoea in one-half of the cases and decreased the breathing rates during the first 10 min of surgery. CONCLUSIONS: Intraoperative use of i.v. fentanyl 1 micro g.kg-1 combined with a regional anaesthetic block is associated with an increased incidence of PONV without any significant contribution to the postoperative pain relief.

The efficacy of caudal ropivacaine 1, 2 and 3 mg x l(-1) for postoperative analgesia in children.

BACKGROUND: The aim of this double blind, randomized, comparative study was to assess the analgesic efficacy and incidence of motor block after caudal block using three different concentrations of ropivacaine, 1, 2 and 3 mg x l(-1), in children 4-12-year-old. METHODS: One hundred and ten children ASA I-II, scheduled for inguinal surgery, were included in the study. After induction of a standardized general anaesthetic technique, all patients received 1 ml x kg(-1) of the ropivacaine solution for a caudal block and were assessed for 8 h after the injection. RESULTS: The ropivacaine was well tolerated in all patients. Median time to treatment with analgesics was 3.3, 4.5 and 4.2 h in the 1, 2 and 3 mg x ml(-1) groups, respectively. During the first 4 h, the pain scores for both a 6-graded faces scale and a 4-graded observer scale were higher in the 1 mg x ml(-1) group than the 3 mg x ml(-1) group. The median sensory block reached T12 in all groups 1 h after the caudal block. Thereafter, the speed of regression was correlated with the ropivacaine concentration. In the patients with a sensory block from T12 and above, the median time to treatment with analgesics was longer than in the children with a sensory block below T12. The incidence of motor block was 28% in the 3 mg x ml(-1) group in comparison with 0 and 13% in the 1 and 2 mg x ml(-1) groups. CONCLUSIONS: It was concluded that 1 ml x kg(-1) of ropivacaine 2 mg x ml(-1) for caudal block provided satisfactory postoperative pain relief after inguinal surgery in 4-12-year-old children. Ropivacaine 1 mg x ml(-1) showed less efficacy while the use of ropivacaine 3 mg x ml(-1) was associated with a higher incidence of motor block with minimal improvement in postoperative pain relief.

Plasma concentrations of ropivacaine following a single-shot caudal block of 1, 2 or 3 mg/kg in children.

BACKGROUND: For documenting the properties of ropivacaine used for regional anaesthesia in children, the relationship between dose and resulting systemic exposure is essential. The aim of this pharmacokinetic part of a randomised, multicentre, double-blind study was to determine the free and total plasma levels of ropivacaine in children aged between 4 and 12 years following a single-shot caudal dose of 1, 2 or 3 mg/kg of ropivacaine for postoperative pain management. METHOD: Following induction of a standardised general anaesthetic (halothane; nitrous oxide: oxygen 60:40), a caudal block using 1 ml/kg ropivacaine in concentrations of 1, 2 or 3 mg/ml was performed in 43 ASA I children (body weight 12-25 kg) scheduled for elective inguinal surgery. Blood samples were collected prior to and 15, 30, 45, 60 and 240 min after placement of the caudal block for determination of total and free ropivacaine plasma concentrations. RESULTS: The peak plasma concentration of total ropivacaine, reached within 15-241 min after the block, increased in proportion to dose, with mean values at 0.27, 0.64 and 0.90 mg/l following 1, 2 and 3 mg/kg respectively. The peak plasma level of free ropivacaine also increased in a dose-proportional manner, with mean levels at 0.014, 0.030 and 0.042 mg/l. The highest individual peak plasma level of free ropivacaine was 0.070 mg/l, well below the threshold levels of CNS toxicity described in adults. No clinical signs of systemic toxicity were observed. CONCLUSION: Following single-shot caudal doses of 1-3 mg/kg in children up to 25 kg and aged between 4 and 12 years, plasma levels of free ropivacaine increase in proportion to dose and all were shown to be within safe limits.

Pharmacokinetics and analgesic effect of ropivacaine following ilioinguinal/iliohypogastric nerve block in children.

BACKGROUND: The aim was to investigate the efficacy, tolerance and pharmacokinetics of ropivavcaine when administered for ilioinguinal/iliohypogastric block in children. METHODS: We examined the pharmacokinetics and analgesic efficacy after ilioinguinal/iliohypogastric nerve block with 3 mg.kg-1 ropivacaine 5 mg.ml-1 in 22 children, aged 1-12 years, who were scheduled for inguinal surgery. Sixteen of 22 patients had a postoperative pain score < 4 (Objective Pain Scale). Nine children were given supplementary analgesics during the first six postoperative hours. RESULTS: The peak plasma concentration of total ropivacaine was 1.50 +/- 0.93 mg.l-1 (mean +/- SD) (range 0.64-4.77 mg.l-1) 15-64 min after the injection. The peak plasma concentration of free ropivacaine was 0.05 +/- 0.03 mg.l-1 (0.02-0.14 mg.l-1), which is well below the threshold for toxicity in adults. The terminal half-life was 2.0 +/- 0.7 h. No safety concerns or symptoms suggestive of systemic toxicity were observed. CONCLUSION: A dose of 3 mg.kg-1 of ropivacaine given as a single ilioinguinal/iliohypogastric nerve block in 1-12-year-old children provides satisfactory postoperative pain relief, and is well tolerated.

Increased levels of S-100 protein after cardiac surgery with cardiopulmonary bypass and general surgery in children.

The aim of this study was to evaluate changes in concentrations of the neurospecific protein S-100 in relation to cardiac surgery with cardiopulmonary bypass (CPB) and noncardiac general surgery in children below 3 years of age. Seventeen children underwent surgery for congenital heart disease and all survived without clinical signs of neurological complications. Samples for plasma concentrations of S-100 in these patients were taken on three occasions in connection with surgery: before the start of surgery, after CPB and finally 16-20 h after CPB. In the noncardiac group of 31 children, S-100 concentrations were measured on two occasions: before surgery and during surgery. In both groups, a significant increase in S-100 concentrations was observed during surgery, although the increase in the CPB group was significantly higher than in the noncardiac group. The CPB group included four children with Down's syndrome who had higher mean S-100 concentrations on all sampling occasions compared to the remaining patients. The peak S-100 concentrations after cardiac surgery were related to the duration of CPB, the time from the termination of CPB to the first post-CPB sample, as well as mean arterial pressure and cerebral arteriovenous lactate difference during rewarming. All the children studied (Down's patients excluded) had age-dependent plasma concentrations of S-100 measured before surgery. It can be concluded that CPB initiates a marked but transient release of S-100 into the systemic circulation during open heart surgery in children who are not developing clinical signs of neurological sequelae.

Postoperative comfort in paediatric outpatient surgery.

Postoperative conditions in hospital and at home were evaluated in 200 paediatric daycase patients by using questionnaires and telephone interviews. Pain was assessed by behaviour observation or a faces rating scale depending on age. Anaesthetic methods, nausea/vomiting, analgesics and parents' aspects were also recorded. Seventy per cent of the patients received regional anaesthesia. Immediate postoperative analgesia was satisfactory in 75% of the children. When the effects of intraoperatively administered analgesics wore off at home almost half the children rated higher than mild pain. The increased degree of pain at home was especially pronounced after regional anaesthesia. The total incidence of nausea/vomiting was 28% and fentanyl caused nausea and vomiting in a significantly higher proportion of cases. The study points out that immediate postoperative comfort obtained by prophylactic analgesia needs to be followed by analgesics given on a continuous basis for the first days after surgery.

Jugular bulb temperature compared with non-invasive temperatures and cerebral arteriovenous oxygen saturation differences during open heart surgery.

Limited information is available about the correlation between cerebral temperature and routine temperature measurements during cardiopulmonary bypass in infants. Nasopharyngeal, tympanic membrane and rectal temperatures were compared with jugular bulb temperature in ten infants operated on with moderate or deep hypothermia. The cerebral arteriovenous saturation differences were correlated with the temperatures at the four measurement sites. The jugular bulb and nasopharyngeal temperatures showed the most rapid response during cooling and rewarming. The tympanic temperature response varied in an unpredictable way. Rectal temperature, which was the target for rewarming, lagged behind during both cooling and rewarming. Overwarming at the end of cardiopulmonary bypass, seen as jugular bulb and nasopharyngeal temperatures exceeding 38 degrees C, was common after deep hypothermia. A high correlation was found between the cerebral arteriovenous oxygen saturation differences and the jugular bulb temperature (r = 0.81) and the nasopharyngeal and the tympanic temperature (r = 0.79), whereas the correlation with rectal temperature was weaker (0.66).

Intraoperative glucose administration influences respiratory quotient during paediatric anaesthesia.

BACKGROUND: Oxidation of carbohydrates and fat yields respiratory quotients (RQ) of 1.0 and 0.7 respectively. Maintained or increased blood glucose concentrations are usually seen during paediatric anaesthesia and surgery even without glucose administration. The aim of the present study was to evaluate whether an intraoperative glucose infusion influences the RQ as an indication of a different metabolic preference in comparison to a glucose-free fluid regime. METHODS: Eighteen children between 0.5 and 24 months of age were studied during anaesthesia with controlled ventilation, oxygen in air, isoflurane, thiopentone, atracurium and fentanyl. Oxygen consumption and carbon dioxide production were measured using indirect calorimetry All children received Ringer acetate as needed; in addition, nine children were given glucose 10%, 3 ml.kg-1.h-1, corresponding to 300 mg.kg-1.h-1. Blood samples for analyses of glucose, lactate, free fatty acids and ketones were taken before and during surgery. RESULTS: RQ was significantly higher in the children given glucose 0.92 +/- 0.08, compared to 0.81 +/- 0.06 in the children without glucose (P < 0.01). Oxygen consumption tended to be higher, although not significantly so, in patients without glucose infusion. Energy expenditure was 1.70 +/- 0.29 kcal.kg-1.h-1, without significant group differences. Higher blood glucose concentrations during surgery were found in the children given glucose. CONCLUSIONS: Our results indicate a higher glucose oxidation rate in patients given glucose during surgery.

Postoperative nausea and vomiting in children using patient-controlled analgesia: the effect of prophylactic intravenous dixyrazine.

BACKGROUND: Although patient-controlled analgesia (PCA) with morphine provides a high degree of satisfactory postoperative analgesia in children, it is often associated with a high incidence of postoperative nausea and vomiting (PONV). Our aim in this study was to evaluate the prophylactic effect of dixyrazine, a phenothiazine with proven anti-emetic properties. METHODS: The incidence of nausea and vomiting was studied in 60 children using PCA after major surgery. The patients were randomised to receive either dixyrazine 0.25 mg kg-1 or placebo on the induction of anaesthesia in a double-blind, placebo-controlled design. The anaesthetic technique was standardised. The PCA pump was programmed to deliver bolus doses of morphine of 20 micrograms kg-1 with a continuous background infusion of 8-10 micrograms kg-1 h-1. Nausea, vomiting, sedation and pain scores were noted every 3 h for a period of 24 h. RESULTS: The morphine consumption of morphine was the same in both groups. During the stay in the recovery room the incidence of vomiting was 3% in the dixyrazine group compared to 30% in the placebo group (P < 0.05). On the ward, 57% versus 83% of the children vomited (P < 0.05). Rescue antiemetics were significantly lower, 30%, in the dixyrazine group compared to 60% in the placebo group (P < 0.05). Higher sedation scores were recorded for the dixyrazine group in the recovery room. No other adverse effects were found. CONCLUSION: A significant number of children using PCA with morphine after major surgery experience PONV. Although prophylactic dixyrazine reduces the incidence and severity of vomiting, the incidence still remains high.

Topical wound anaesthesia in children--a temporary postoperative pain relief.

BACKGROUND: Administration of local anaesthetics into the surgical wound may modulate pain at the peripheral level. A previous study in adults has shown good analgesic effects of topical lidocaine in wounds after herniorrhaphy. METHODS: Postoperative pain relief after topical administration of 10% lidocaine aerosol in the surgical wound was investigated in a randomised, double-blind study in children undergoing inguinal hernia repair. Forty-four patients aged between 9 months and 11 years were randomised into three groups. One group received active treatment with a lidocaine aerosol 2.5-4.7 mg kg-1, one group received a placebo aerosol and one control group was untreated. Postoperative pain was evaluated by nurse assessment, self-assessment and wound palpation 0, 1, 4 and 12 h after arrival in the recovery room. RESULTS: After 1 h the incidence of pain, as estimated by behavioural assessment and self-assessment, was significantly reduced in the lidocaine group in comparison to the placebo group, but not in comparison to the control group. The reaction on wound palpation was significantly reduced in the lidocaine group compared to both the placebo and control groups. At 0, 4 and 12 h no significant differences between the groups were observed. Plasma lidocaine concentrations were measured in six patients. Maximum individual concentrations were low, ranging from 0.17 to 0.86 microgram ml-1. CONCLUSION: A very short and clinically insignificant pain relief is obtained following the administration of a lidocaine aerosol in the surgical wound. A low pain level in this model may limit the possibility to detect an effect of lidocaine.

Open heart surgery; pump prime effects and cerebral arteriovenous differences in glucose, lactate and ketones.

This study included 17 young children, who were operated with cardioplumonary bypass for congenital heart defects and were cooled to 20 degrees C or 25 degrees C. No glucose, except for the pump prime solution, was administered during surgery. Samples of arterial blood, cerebral venous blood from the jugular bulb and mixed venous blood from the bypass circuit were obtained and analysed for concentrations of glucose, lactate and ketones as well as oxygen saturation. The prime content of lactate significantly contributed to the arterial lactate concentrations, which together with the cerebral arteriovenous (A-V) lactate differences remained elevated throughout the bypass period. The prime content of glucose had less influence on the arterial concentrations and these did not increase until the rewarming period, when indications of gluconeogenesis from lactate were found. Arterial ketone concentrations also increased during rewarming in parallel with significant cerebral uptake of ketones. The lowest cerebral A-V glucose, lactate and oxygen saturation differences were found at the target minimum temperature and this effect was significantly more pronounced in the patients cooled to 20 degrees C.

Methaemoglobin formation after the use of EMLA cream in term neonates.

EMLA cream 5% (a eutectic mixture of lidocaine and prilocaine) is a topical anaesthetic that has become widely used to minimize pain from venipuncture in children. It has not, however, been recommended in neonates owing to the potential risk of methaemoglobinaemia induced by prilocaine. The aim of this study was to establish the safety of 1 g EMLA cream 5% used on intact skin in term neonates. Forty-seven neonates, aged 0-3 months, with a postconceptual age of > or = 37 weeks and a body weight between 2.8 and 5.7 kg, were included in a double-blind, randomized, placebo-controlled study. After baseline observations a total dose of 1.0 g EMLA/placebo was applied to two sites (0.5 g site(-1)) for 60-70 min. Venous methaemoglobin (metHb) levels were determined in each patient at baseline and at three randomly assigned times, 0.5-18 h after application. Following application of the cream, the mean metHb levels were 1.17% (range 0.50-2.53) in the EMLA group and 0.96% (range 0.50-1.53) in the placebo group. The metHb concentrations were significantly higher in the EMLA group in the intervals from 3.5 to 13 h after application than in the placebo group, but were well below potentially harmful levels. Based on these results, a 1-h application of 1 g EMLA cream is safe when used on the intact skin of term neonates below 3 months of age.

Gait analysis, isokinetic muscle strength measurement in patients with Parkinson's disease.

The aim of this study was to describe motor performance in Parkinson patients in relation to controls. Gait, concentric isometric and eccentric strength in the ankle dorsiflexors were investigated in 25 patients with Parkinson's disease and in 37 control subjects of the same age. In patients concentric torque was significantly lowered but, eccentric torque was significantly lowered in male patients only. Among controls a significant difference in strength was found between sexes. This was not found in the patient group. No correlation between strength tests and clinical ratings was found in the patient group. Patients walked with significantly lower maximum and ordinary velocity, compared with controls. At constant velocity, stride length was shorter, single support had a shorter duration. The duration for heel on to ball on in males was shorter, reflecting the flat foot strike of Parkinson patients. Single support and the duration of heel on to ball on correlated significantly to the clinical ratings in male but not in female patients. In the male group of patients there was a relation between concentric strength on the one hand and gait velocity, stride length and stride frequency on the other. Female patients generally had fewer symptoms and less deviation from their respective controls in the measurements. The comparatively simple neurophysiological tests presented here may be suitable for evaluation of patients with Parkinson's disease.

Alterations in gait resulting from deliberate changes of arm-swing amplitude and phase.

OBJECTIVE: The purpose of the study was to reach a better understanding of the influence of arm movement in human gait. DESIGN: The experiment involved the adoption of different arm-swing patterns by normal subjects who walked in a gait laboratory. BACKGROUND: The reciprocal swinging of the arms in walking plays an important role in gait, but the details require further research. More insight into the role of the arm-swing in gait could be obtained by adopting different arm-swing patterns while walking at different speeds. METHOD: Thirteen normal subjects were therefore requested to walk adopting different arm-swing patterns which included, one or both arms strapped to the body, full reciprocal excursion of both arms, pace walking and swinging the arms in parallel. From measurements made at different speeds of walking, regressions were calculated which made it possible to compare basal gait characteristics of the different arm patterns. RESULTS: Maximum velocity decreased in all cases. In the test conditions where the arms were strapped, the subjects increased velocity by increasing stride frequency more than stride length. In the other conditions the reverse was the case. CONCLUSION: The experiments show that the gait pattern is very much influenced by changes in arm-swing but the effects are related to the pattern of arm-swing and the speed of walking.

A stable late soleus EMG response elicited by cortical stimulation during voluntary ankle dorsiflexion.

Transcranial electrical or magnetic stimulation was performed in 47 experiments on 42 normal adult subjects. Surface compound muscle action potentials were recorded from the antagonistic tibialis anterior (TA) and soleus (SOL) muscles. A stable late response recorded from SOL during voluntary ankle dorsiflexion is described and called soleus MEP-80. Its origin has been studied with different experimental procedures. (1) It is only obtained during active voluntary dorsiflexion of the ankle within 70-100 msec (mean 86.9 +/- 6.4 msec) whereas passive dorsiflexion does not promote such a response. The size of SOL MEP-80 was always bigger than the primary SOL response. (2) A similar constant response has not been obtained during voluntary plantar flexion from SOL and TA muscles. (3) SOL MEP-80 is not changed significantly by the Jendrassik manoeuvre. (4) It is not obtained or is suppressed when the subject is sitting with the feet free in space. On the other hand, it is obtained when the subject is standing, especially when standing is made difficult. (5) SOL MEP-80 has not been obtained by brain-stem, spinal cord or root stimulation. (6) A later response of longer than 100 msec latency was sometimes obtained at rest but such an S100 soleus response was abolished or transformed to the SOL MEP-80 immediately during ankle dorsiflexion. (7) It is concluded that SOL MEP-80 is a polysynaptic extensor response related to postural mechanisms and originating through convergence of descending motor commands and peripheral sensory feedback.

Effects of propranolol pretreatment on cerebral blood flow, oxygen uptake and catecholamines during metabolic acidosis following E. coli endotoxin in dogs.

After an intravenous injection of E. coli endotoxin in dogs a decrease in cerebral blood flow (CBF) and an increase in cerebral metabolic rate of oxygen (CMRo2) have been shown to occur. In metabolic acidosis following endotoxin CMRo2 increased with decreasing pH. A possible explanation for the increased CMRo2 after endotoxin and metabolic acidosis seems to be a damage of the blood-brain barrier (BBB) by endotoxin. This gives possibilities for a leakage of hydrogen ions and circulating monoamines from the blood to the brain, thus affecting the cerebral blood flow and metabolism. The effects of an E. coli endotoxin injection on CBF and CMRo2 during metabolic acidosis and beta-adrenoceptor blockade were studied in eight anaesthetized dogs. All the dogs were pretreated with propranolol (PPL), per os 12.5 mg.kg-1 twice a day for one week. Metabolic acidosis (pH 7.01-7.30) was achieved by an intravenous infusion of hydrochloric acid. Endotoxin E. coli lipopolysaccharide O 111:B 4 was given as an intravenous injection of 1 mg.kg-1 bodyweight over a 5 min period. Another five animals, published earlier, with the same experimental protocol but without PPL, constituted a control group. After endotoxin no increase in CMRo2 or CBF was observed with increasing acidosis in the PPL-group. In the control group, after endotoxin, both CBF and CMRo2 increased with decreasing pH. This resulted in a significant difference in both CBF and CMRo2 between the groups in the pH range 7.01-7.15. The present results indicate that the increase in CMRo2 and CBF with metabolic acidodis in endotoxinaemia is mediated via beta-adrenoceptors.

Effects of arterial hypoxia and beta-adrenoceptor blockade on cerebral blood flow and oxygen uptake following E. coli endotoxin in dogs.

Earlier studies in normoxia have shown that an endotoxin injection in dogs leads to an increase in cerebral metabolic rate of oxygen (CMRo2), a decrease in cerebral blood flow (CBF) and increased concentrations of monoamines in blood and cerebrospinal fluid (CSF). In animals pretreated with propranolol (PPL) the CMRo2 increase was abolished and thus beta-adrenoceptor mediated. Arterial hypoxia normally increases CBF without any influence on CMRo2. The aim of this study was to investigate the effects of moderate arterial hypoxia on CBF, CMRo2 and catecholamine concentrations in blood and CSF after endotoxin with and without pretreatment with PPL. Three groups of dogs were studied. Group 1: Six animals were subjected to arterial hypoxia without any other intervention. Group 2: Six animals were given an endotoxin injection (E. coli lipopolysaccharide O 111: B 4), before the induction of hypoxia. Group 3: Eight animals were pretreated with PPL per os, 12.5 mg.kg-1 twice a day for one week before the experiments, and the effects of arterial hypoxia were studied both before and after an intravenous injection of endotoxin. Two levels of hypoxia were studied; oxygen saturation in arterial blood aiming at 75 and 50%. Endotoxin was given intravenously in a dose of 1 mg.kg-1 bodyweight over a 5 minute period. After an endotoxin injection, the response to arterial hypoxia was an increase in CMRo2, in contrast to the unchanged CMRo2 without endotoxin. After pretreatment with PPL the increase in CMRo2 after endotoxin was prevented. The CBF reaction to hypoxia was uniformly an increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Early postoperative lipid administration after neonatal surgery.

The ability of neonates to eliminate and utilize lipid emulsions after surgery was investigated in 12 patients. All were subjected to major surgery within 29 h of birth. All neonates were given 10% glucose iv intraoperatively. Six patients continued with 10% glucose iv for 24 h postoperatively and 6 patients received a combination of 5% glucose and soy bean emulsion (Intralipid 20%). Both regimes provided equal amounts of fluid and energy. Blood glucose, lactate, triglycerides, free fatty acids, fractions of fatty acids in triglycerides, 3-hydroxybutyrate and arterial blood gases were measured at predetermined intervals throughout this period. Administration of a lipid emulsion early after neonatal surgery was well tolerated and utilized, with some latency. Concentrations of triglycerides, free fatty acids and 3-hydroxybutyrate were higher in the lipid group, but no accumulation of these substances was found. Palmitinic and linoleic acid were also higher in the lipid group.