[Horner's syndrome in the delivery room : a rare complication of labour epidural analgesia]

Horner's syndrome is a rare and benign complication of neuraxial analgesia during labour. We report the case of a Gravida 1 patient complaining of ptosis, enophthalmia and meiosis during labour, a few hours after a lumbar epidural analgesia was initiated.

Placenta Accreta Spectrum Part II: hemostatic considerations based on an extended review of the literature

"Placenta accreta spectrum" (PAS) is a rare but serious pregnancy condition where the placenta abnormally adheres to the uterine wall and fails to spontaneously release after delivery. When it occurs, PAS is associated with high maternal morbidity and mortality-as PAS management can be particularly challenging. This two-part review summarizes current evidence in PAS management, identifies its most challenging aspects, and offers evidence-based recommendations to improve management strategies and PAS outcomes. The first part of this two-part review highlighted the general anesthetic approach, surgical and interventional management strategies, specialized "centers of excellence," and multidisciplinary PAS treatment teams. The high rates of PAS morbidity and mortality are often provoked by PAS-associated coagulopathies and peripartal hemorrhage (PPH). Anesthesiologists need to be prepared for massive blood loss, transfusion, and to manage potential coagulopathies. In this second part of this two-part review, we specifically reviewed the current literature pertaining to hemostatic changes, blood loss, transfusion management, and postpartum venous thromboembolism prophylaxis in PAS patients. Taken together, the two parts of this review provide a comprehensive survey of challenging aspects in PAS management for anesthesiologists.

Placenta accreta spectrum part I: anesthesia considerations based on an extended review of the literature

"Placenta accreta spectrum" (PAS) describes abnormal placental adherence to the uterine wall without spontaneous separation at delivery. Though relatively rare, PAS presents a particular challenge to anesthesiologists, as it is associated with massive peripartum hemorrhage and high maternal morbidity and mortality. Standardized evidence-based PAS management strategies are currently evolving and emphasize: "PAS centers of excellence", multidisciplinary teams, novel diagnostics/pharmaceuticals (especially regarding hemostasis, hemostatic agents, point-of-care diagnostics), and novel operative/interventional approaches (expectant management, balloon occlusion, embolization). Though available data are heterogeneous, these developments affect anesthetic management and must be considered in planed anesthetic approaches. This two-part review provides a critical overview of the current evidence and offers structured evidence-based recommendations to help anesthesiologists improve outcomes for women with PAS. This first part discusses PAS management in centers of excellence, multidisciplinary care team, anesthetic approach and monitoring, surgical approaches, patient safety checklists, temperature management, interventional radiology, postoperative care and pain therapy. The diagnosis and treatment of hemostatic disturbances and preoperative prepartum anemia, blood loss, transfusion management and postpartum venous thromboembolism will be addressed in the second part of this series.

Guidelines for the management of urgent obstetric situations in emergency medicine, 2022

OBJECTIVE

To provide recommendations on the management of urgent obstetrical emergencies outside the maternity ward.

DESIGN

A group of 24 experts from the French Society of Emergency Medicine (SFMU), the French Society of Anaesthesia and Intensive Care Medicine (SFAR) and the French College of Gynaecologists and Obstetricians (CNGOF) was convened. Potential conflicts of interest were formally declared at the outset of the guideline development process, which was conducted independently of industry funding. The authors followed the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method to assess the level of evidence in the literature. The potential drawbacks of strong recommendations in the presence of low-level evidence were highlighted. Some recommendations with an insufficient level of evidence were not graded.

METHODS

Eight areas were defined: imminent delivery, postpartum haemorrhage (prevention and management), threat of premature delivery, hypertensive disorders in pregnancy, trauma, imaging, cardiopulmonary arrest, and emergency obstetric training. For each field, the expert panel formulated questions according to the PICO model (population, intervention, comparison, outcomes) and an extensive literature search was conducted. Analysis of the literature and formulation of recommendations were conducted according to the GRADE method.

RESULTS

Fifteen recommendations on the management of obstetrical emergencies were issued by the SFMU/SFAR/CNGOF panel of experts, and 4 recommendations from formalised expert recommendations (RFE) established by the same societies were taken up to answer 4 PICO questions dealing with the pre-hospital context. After two rounds of voting and several amendments, strong agreement was reached for all the recommendations. For two questions (cardiopulmonary arrest and inter-hospital transfer), no recommendation could be made.

CONCLUSIONS

There was significant agreement among the experts on strong recommendations to improve practice in the management of urgent obstetric complications in emergency medicine.

Pregnancy and delivery in a patient with a Fontan circulation and primary ciliary dyskinesia: A case report

A patient had primary ciliary dyskinesia with a complex cardiac malformation. As a child, she had benefited from a Fontan surgery to maintain a proper cardiac function. In such patients, whether it is safe to become pregnant is controversial. This case illustrates the possibility of carrying a pregnancy to term and providing a vaginal birth if a rigorous preconception consultation is performed to ensure care by a multidisciplinary specialized team, and the patient is properly informed of the risks.

[Spontaneous rupture of a splenic artery aneurysm during the third trimester of pregnancy]

We report the case of a 24-year-old female patient with spontaneous rupture of a splenic artery aneurysm in the third trimester of pregnancy. Pregnancy, throughout the physiological and hormonal changes it imposes, promotes the occurrence of aneurysm of the splenic artery and its rupture. Although this is a rare complication, its prognosis is severe and its typical clinical picture associating abdominal pain, hypotension and anemia is misleading for the clinician who likelier evokes a retroplacental hematoma or an uterine rupture. The maternal and foetal survival depends on rapid diagnosis and multidisciplinary management. Thus, it's important for the clinician to consider this differential diagnosis when abdominal pain or hemoperitoneum occurs in pregnant woman, particularly during the third trimester of pregnancy.

Management practices for postdural puncture headache in obstetrics: a prospective, international, cohort study

BACKGROUND

Accidental dural puncture is an uncommon complication of epidural analgesia and can cause postdural puncture headache (PDPH). We aimed to describe management practices and outcomes after PDPH treated by epidural blood patch (EBP) or no EBP.

METHODS

Following ethics committee approval, patients who developed PDPH after accidental dural puncture were recruited from participating countries and divided into two groups, those receiving EBP or no EBP. Data registered included patient and procedure characteristics, headache symptoms and intensity, management practices, and complications. Follow-up was at 3 months.

RESULTS

A total of 1001 patients from 24 countries were included, of which 647 (64.6%) received an EBP and 354 (35.4%) did not receive an EBP (no-EBP). Higher initial headache intensity was associated with greater use of EBP, odds ratio 1.29 (95% confidence interval 1.19-1.41) per pain intensity unit increase. Headache intensity declined sharply at 4 h after EBP and 127 (19.3%) patients received a second EBP. On average, no or mild headache (numeric rating score≤3) was observed 7 days after diagnosis. Intracranial bleeding was diagnosed in three patients (0.46%), and backache, headache, and analgesic use were more common at 3 months in the EBP group.

CONCLUSIONS

Management practices vary between countries, but EBP was more often used in patients with greater initial headache intensity. EBP reduced headache intensity quickly, but about 20% of patients needed a second EBP. After 7 days, most patients had no or mild headache. Backache, headache, and analgesic use were more common at 3 months in patients receiving an EBP.

Preeclampsia: an update

Preeclampsia was formerly defined as a multisystemic disorder characterized by new onset of hypertension (i.e. systolic blood pressure (SBP) ≥ 140 mmHg and/or diastolic blood pressure (DBP) ≥ 90 mmHg) and proteinuria (> 300 mg/24 h) arising after 20 weeks of gestation in a previously normotensive woman. Recently, the American College of Obstetricians and Gynecologists has stated that proteinuria is no longer required for the diagnosis of preeclampsia. This complication of pregnancy remains a leading cause of maternal morbidity and mortality. Clinical signs appear in the second half of pregnancy, but initial pathogenic mechanisms arise much earlier. The cytotrophoblast fails to remodel spiral arteries, leading to hypoperfusion and ischemia of the placenta. The fetal consequence is growth restriction. On the maternal side, the ischemic placenta releases factors that provoke a generalized maternal endothelial dysfunction. The endothelial dysfunction is in turn responsible for the symptoms and complications of preeclampsia. These include hypertension, proteinuria, renal impairment, thrombocytopenia, epigastric pain, liver dysfunction, hemolysis-elevated liver enzymes-low platelet count (HELLP) syndrome, visual disturbances, headache, and seizures. Despite a better understanding of preeclampsia pathophysiology and maternal hemodynamic alterations during preeclampsia, the only curative treatment remains placenta and fetus delivery. At the time of diagnosis, the initial objective is the assessment of disease severity. Severe hypertension (SBP ≥ 160 mm Hg and/or DBP ≥ 110 mmHg), thrombocytopenia < 100.000/μL, liver transaminases above twice the normal values, HELLP syndrome, renal failure, persistent epigastric or right upper quadrant pain, visual or neurologic symptoms, and acute pulmonary edema are all severity criteria. Medical treatment depends on the severity of preeclampsia, and relies on antihypertensive medications and magnesium sulfate. Medical treatment does not alter the course of the disease, but aims at preventing the occurrence of intracranial hemorrhages and seizures. The decision of terminating pregnancy and perform delivery is based on gestational age, maternal and fetal conditions, and severity of preeclampsia. Delivery is proposed for patients with preeclampsia without severe features after 37 weeks of gestation and in case of severe preeclampsia after 34 weeks of gestation. Between 24 and 34 weeks of gestation, conservative management of severe preeclampsia may be considered in selected patients. Antenatal corticosteroids should be administered to less than 34 gestation week preeclamptic women to promote fetal lung maturity. Termination of pregnancy should be discussed if severe preeclampsia occurs before 24 weeks of gestation. Maternal end organ dysfunction and non-reassuring tests of fetal well-being are indications for delivery at any gestational age. Neuraxial analgesia and anesthesia are, in the absence of thrombocytopenia, strongly considered as first line anesthetic techniques in preeclamptic patients. Airway edema and tracheal intubation-induced elevation in blood pressure are important issues of general anesthesia in those patients. The major adverse outcomes associated with preeclampsia are related to maternal central nervous system hemorrhage, hepatic rupture, and renal failure. Preeclampsia is also a risk factor for developing cardiovascular disease later in life, and therefore mandates long-term follow-up.

[Obstetrical epidural analgesia and postpartum backache]

Backache is a common problem in the general population. The prevalence of backpain is increased during pregnancy and after delivery. Early studies have suggested that labor epidural analgesia might be associated with an increased incidence of backache in the postpartum period. However, these initial studies were retrospective and their design included several methodological deficiencies. All the prospective studies published afterwards (prospective cohort studies and 3 randomized controlled trials) yield the same result: there is no relationship between labor epidural analgesia and long-term postpartum backpain. Pregnant women must be aware of this in order to make an informed and appropriate choice about labor epidural analgesia, the most effective technique for intrapartum pain relief.

[Post-dural puncture headache: treatment and prevention]

Post-dural puncture headache (PDPH) is a common iatrogenic and incapacitating complication. Dural puncture can be intentional (spinal block, myelography,...) or accidental (epidural block). Risk factors are well described and the obstetric patient is at high risk for PDPH. The treatment of PDPH is not standardised. Many options have been proposed, but only the epidural blood patch has apparent benefits. A few measures have been suggested to prevent PDPH after unintentional dural puncture, but none has been shown to work with certainty.

[Pseudoxanthoma elasticum and obstetric epidural analgesia: report of a case]

Pseudoxanthoma elasticum is a rare inherited disorder of the elastic tissue characterised by multisystem manifestations. Skin, eyes, gastro-intestinal system and cardiovascular system are the major affected systems. We describe the anaesthetic management of a parturient affected by this disease.

Management of severe preeclampsia

Features of severe preeclampsia include severe proteinuric hypertension and symptoms of central nervous system dysfunction, hepatocellular injury, thrombocytopenia, oliguria, pulmonary oedema, cerebrovascular accident and severe intrauterine growth restriction. Women with severe preeclampsia must be hospitalized to confirm the diagnosis, to assess the severity of the disease, to monitor the progression of the disease and to try to stabilize the disease. Severe preeclampsia may be managed expectantly, in selected cases. The objective of expectant management in these patients is to improve neonatal outcome. Expectant management is based on antihypertensive treatment and prevention of end organ dysfunction. Antihypertensive treatment improves maternal outcome but has the potential to be deleterious for the foetus. Plasma volume expansion has been suggested for severe preeclampsia but trials failed to show any benefit. Magnesium sulfate is the anticonvulsivant of choice to treat or prevent eclampsia when indicated. Antenatal corticosteroids are recommended in severely preeclamptic women with 26-34 weeks gestation. Timing of delivery is based upon gestational age, severity of preeclampsia, maternal and foetal risks.

[Is a coagulation blood test compulsory before neuraxial blockade for labor analgesia?]

Neuraxial blockade such as epidural, spinal or combined spinal-epidural analgesia is considered to be the best technique for labour analgesia. Even if epidural hematoma is a very rare complication of neuraxial blockade, it may result in severe and definitive neurological injuries. This rare complication is usually associated with coagulation abnormalities. This is the reason why many physicians order routine coagulation screening tests before performing neuraxial blockade. This practice is questionable from the evidence-based medicine and the economic point of view. According to the guidelines published by several scientific societies, no routine coagulation screening tests are required in the absence of any history or clinical suspicion of coagulation impairment. The aim of the present article is to delineate the appropriate attitude in this context.

[Treatment of severe preeclampsia: until when and for what risks/benefits?]

The four major hypertensive disorders related to pregnancy are preeclampsia, chronic hypertension, preeclampsia superimposed upon chronic hypertension, and gestational hypertension. The development of hypertension and proteinuria in pregnancy is usually due to preeclampsia, particularly in a primigravida. These findings typically become apparent in the latter part of the third trimester and progress until delivery, but some women develop symptoms in the latter half of the second trimester, or intrapartum, or the early postpartum period. Preeclampsia is characterized as mild or severe. Severe hypertension, coagulopathy, thrombocytopenia, liver function abnormalities, and fetal growth restriction are features of severe disease. Laboratory evaluation should assess haemoglobin/hematocrit and platelet count, renal and hepatic function, as well as assessment of fetal well-being and growth. Timing of delivery is based upon gestational age, maternal and fetal condition, and the severity of preeclampsia. Maternal end organ dysfunction and nonreassuring tests of fetal well-being are indications for delivery at any gestational age. Antihypertensive treatment aims at protecting the mother from severe hypertensive encephalopathy, but may jeopardize the fetus. We recommend antenatal corticosteroids (betamethasone) be given to women with preeclampsia at 26 to 34 weeks of gestation. Magnesium sulfate is more effective than phenytoin for prevention of eclamptic seizures.

Bispectral Index Profile During Carotid Cross Clamping

This study aimed at investigating the Bispectral Index (BIS) profile during carotid cross clamping (CXC). The study involved a pilot group of 10 patients undergoing routine carotid endarterectomy with shunt insertion under total intravenous anesthesia, and a study group of 26 additional patients. In all patients, rates of propofol and remifentanil providing a steady-state level of hypnosis (BIS: 40-60) were maintained constant throughout a recording period ranging from 3 minutes before CXC to shunt insertion. BIS was recorded throughout this period and the internal carotid backflow observed at the time of shunt insertion was graded as good, moderate, or poor. In addition, A-Line Autoregressive Index (AAI) and processed electroencephalogram (EEG) parameters were recorded in patients of the study group. All parameters were averaged over 1 minute before CXC, at CXC, 1, 2, and 3 minutes after CXC, and at shunt insertion. Statistical analysis was performed using chi2, Friedman, and Spearman correlation tests. For technical reasons, reliable AAI, BIS monitor-derived, and other processed EEG data were obtained in 24, 25, and 18 patients of the study group, respectively. During the first 3 minutes after CXC, BIS increased over 60 [68.8 (6.1)] in 47%, decreased below 40 [34.9 (4.4)] in 25%, and remained in the 40 to 60 range in 28% of all recruited patients. A BIS increase was more frequently observed in patients with moderate or poor than in those with good internal carotid backflow (78, 67, and 29%, respectively). It was significantly correlated to an increase in AAI and EEG amplitude, a decrease in EEG suppression ratio, and a shorter time between induction of anesthesia and CXC. A BIS decrease was significantly correlated to an increase in suppression ratio and a longer time between induction and CXC. In conclusion, during CXC under a constant level of intravenous anesthesia, BIS may increase, decrease, or remain unchanged. The paradoxical BIS increase could be related to borderline ischemia, a change in brain anesthetic agent concentration, or a change in the nociceptive-antinociceptive balance associated with a CXC-elicited painful stimulation. Caution should be used when interpreting BIS value during CXC.

Blood glucose concentration profile after 10 mg dexamethasone in non-diabetic and type 2 diabetic patients undergoing abdominal surgery

BACKGROUND

Dexamethasone prevents postoperative nausea and vomiting but may increase blood glucose. We compared blood glucose concentrations after dexamethasone in non-diabetic and type 2 diabetic patients undergoing surgery and looked for any association with preoperative glycosylated haemoglobin [HbA (1c)] and BMI.

METHODS

Sixty three patients were enrolled: 32 were non-diabetic (Group ND) and 31 type 2 diabetic (Group D) without insulin treatment. Anaesthesia was induced using i.v. anaesthetic agents and maintained with sevoflurane. All patients received 10 mg dexamethasone at induction. Blood glucose concentrations were measured at induction and then every 60 min for 240 min. Data were analysed using anova. Effects of HbA (1c) and BMI were investigated using linear correlation and logistic regression.

RESULTS

Blood glucose concentrations increased significantly over time and peaked at 120 min after 10 mg dexamethasone in both groups. The magnitude of increase was comparable between the groups [mean (SD) 29 (19) and 35 (19)% of baseline in Group D and Group ND, respectively]. Maximum concentrations were higher in Group D [8.97 (1.51) mmol litre(-1), range 6.67-12.94 mmol litre(-1)] than in Group ND [7.86 (1.00) mmol litre(-1), range 5.78-10.00 mmol litre(-1)]. There was a significant correlation between the maximum concentrations and BMI (R(2)=0.21) or HbA (1c) (R(2)=0.26). Logistic regression analysis revealed that the higher the BMI, the lower the HbA (1c) threshold associated with an increased probability (>0.5) of observing blood glucose levels higher than 8.33 mmol litre(-1) during 240 min after dexamethasone administration. Similarly, the higher the HbA (1c), the lower the BMI threshold associated with the same probability.

CONCLUSIONS

After 10 mg dexamethasone, blood glucose levels increase in non-diabetic and type 2 diabetic patients undergoing abdominal surgery. Poorly controlled diabetes and severe obesity can influence the development of hyperglycaemia.

Effects of nitrous oxide on spectral entropy of the EEG during surgery under balanced anaesthesia with sufentanil and sevoflurane

BACKGROUND

Spectral entropy of the electroencephalogram (EEG) has been proposed to monitor anaesthetic depth. We investigated the effect of nitrous oxide on response (RE) and state entropy (SE) of the EEG during lumbar disc surgery under anaesthesia with sufentanil and sevoflurane.

METHODS

In an open study, anaesthesia was induced with propofol and sufentanil, and maintained with 2% end-tidal sevoflurane concentration in air/oxygen (FiO2 = 0.4) in 25 patients. During surgery, nitrous oxide was randomly administered either at 0 or at 60% end-tidal concentration in 10 (control group) and 15 patients (nitrous oxide group), respectively. RE and SE were recorded at 2.5 min intervals for 10 min before randomization and for 25 min either continuously (control) or after achieving the target nitrous oxide concentration.

RESULTS

Two patients who received nitrous oxide were excluded from statistical analysis because of protocol violation. Nitrous oxide provoked a significant decrease in RE and SE from 46.2 +/- 11.1 and 44.3 +/- 11.1 to a lowest value of 27.8 +/- 8.3 and 27.1 +/- 8.9, respectively. The decrease in entropy persisted during the 25 min recording period.

CONCLUSIONS

Addition of nitrous oxide during balanced anaesthesia with sufentanil and sevoflurane provokes a decrease in response and state entropy of the EEG during lumbar disc surgery.

Recovery from neuromuscular block after an intubation dose of cisatracurium and rocuronium in lumbar disc surgery

BACKGROUND AND OBJECTIVE

Residual muscle paralysis remains a concern for anaesthesiologists. This study investigated the recovery from neuromuscular block (NMB) after an intubation dose of cisatracurium (C) or rocuronium (R) in 32 patients undergoing lumbar disc surgery.

METHODS

Anaesthesia was induced with propofol and sufentanil, and maintained with sevoflurane in nitrous oxide/oxygen. Patients were randomised to receive twice the ED95 of either cisatracurium (GC) or rocuronium (GR) before tracheal intubation. After placement in prone position, neuromuscular transmission was monitored at the wrist by accelerometry. NMB was antagonised when the TOF ratio (TOFR) was < 0.75 at muscle closure. The time from muscle relaxant to muscle closure, and to TOFR of 0.25 and of 0.50 were recorded. Data were analysed using Student's t-tests, chi-squared tests and two-way mixed-designed ANOVA's. The prediction probability (Pk) of the times from muscle relaxant to muscle closure, and to TOFR of 0.25 for the necessity to antagonize NMB was calculated in both groups. P < 0.05 was considered statistically significant.

RESULTS

NMB was antagonized in 8 (GC) and 6 (GR) patients, respectively. The time from muscle relaxant to muscle closure was shorter in patients whose NMB was antagonized. The Pk of this time was significant in GC (0.85) but not in GR (0.69). In GR contrarily to GC, the times to a TOFR of 0.25 and 0.50 were longer in patients whose NMB was antagonized. The Pk of the time to TOFR of 0.25 was significant in GR (0.95) but not in GC (0.64).

CONCLUSIONS

A single dose of cisatracurium or rocuronium may be associated to some degree of NMB at the end of lumbar surgery, depending on the duration of surgery and on the duration of action of the muscle relaxant which is more variable for rocuronium than for cisatracurium.

Effect of intra-operative magnesium sulphate on pain relief and patient comfort after major lumbar orthopaedic surgery

The effects of intra-operative magnesium sulphate on pain relief after major lumbar surgery were investigated in 24 patients. Patients were randomly allocated to receive either an infusion of 50 mg x kg(-1) magnesium sulphate or an equivalent volume of saline at induction of anaesthesia. Anaesthesia was induced with propofol and remifentanil. Tracheal intubation was facilitated using rocuronium. Maintenance was achieved with remifentanil and sevoflurane in nitrous oxide/ oxygen. Intra-operative monitoring included standard equipment and neuromuscular transmission. During surgery, neuromuscular block recovery was longer in the magnesium group. Postoperative opioid consumption and pain scores were lower in the magnesium group. The first night's sleep and the global satisfaction scores were better in the magnesium group. The results of the study support magnesium sulphate as a useful adjuvant for postoperative analgesia after major lumbar surgery.

Effect of nitrous oxide on the bispectral index and the 95% spectral edge frequency of the electroencephalogram during surgery

We studied the effect of nitrous oxide on the bispectral index and 95% spectral edge frequency of the electroencephalogram in 20 patients undergoing lumbar surgery under general anaesthesia combined with epidural administration of 5 mg morphine. Anaesthesia was induced with propofol and sufentanil, and maintained with sevoflurane in air/oxygen adjusted to keep the bispectral index between 40 and 60. One and a half hours after the start of surgery, nitrous oxide was administered in a randomised sequence of concentrations (20, 40 and 60% end-expired). Under steady-state conditions, mean (SD) bispectral index and spectral edge frequency decreased as end-tidal concentration of nitrous oxide increased, from 47.7 (4.3) and 15.6 (1.3) at 0% nitrous oxide to 39.8 (6.3) and 14.3 (1.8) at 60% nitrous oxide. A negative correlation was found between nitrous oxide concentration and bispectral index (r = -0.48; p < 0.01) and spectral edge frequency (r = -0.39; p < 0.05). We conclude that this dose-dependent decrease in bispectral index and spectral edge frequency induced by nitrous oxide may reflect the level of analgesia associated with the anaesthetic regimen.

Effects of ephedrine on the onset time of neuromuscular block and intubating conditions after cisatracurium: preliminary results

We studied the effects of intravenous ephedrine on the onset time and the intubating conditions 2 min after a bolus dose of cisatracurium (0.15 mg kg-1). Thirty patients anaesthetized with sufentanil and propofol were randomly divided in 2 groups to receive either ephedrine (70 micrograms.kg-1) or saline, 5 s before propofol. Cisatracurium was administered after loss of consciousness. Neuromuscular block was assessed at the adductor pollicis using accelography. Tracheal intubation was performed 2 min after cisatracurium injection and rated as excellent, good, poor or bad. At intubation, neuromuscular block (% height of control T1) was greater in patients receiving ephedrine (36.1 +/- 25.8% vs 57.9 +/- 25.1%) (mean +/- SD). The frequency of excellent intubating conditions was higher after ephedrine (86.6%) than after saline (40.0%). The onset time of cisatracurium was shorter after ephedrine (167 +/- 64.8 s vs 234.9 +/- 63.1 s). Thus, a low dose of ephedrine given before induction of anaesthesia improves the intubating conditions 2 min after 0.15 mg kg-1 cisatracurium and this effect likely relates to a quicker onset of neuromuscular block.

Effects of mild hypothermic cardiopulmonary bypass on EEG bispectral index

We studied the effect of mild hypothermic cardiopulmonary bypass (30 degrees C) on the EEG Bispectral Index in 10 patients undergoing elective CABG. BIS was recorded at 11 event-related time points during the procedure. After a significant decrease at the induction of anaesthesia, BIS was not further modified during the procedure. BIS was neither affected by surgical stimulation nor by CPB and mild hypothermia. We conclude that we did not find any reason to preclude the use of BIS to assess the hypnotic effects of anaesthetics during normothermic or mild hypothermic CPB.

Target-controlled infusion of propofol and remifentanil combined with bispectral index monitoring for awake craniotomy

We describe the target-controlled administration of propofol and remifentanil, combined with monitoring of the bispectral index, during an awake craniotomy for removal of a left temporo-parietal tumour near the motor speech centre. Target concentrations of the two drugs were adjusted according to the patient's responses to painful stimuli and surgical events, and the need for speech testing. Allowing the effect-site concentrations of propofol and remifentanil to decrease during surgery allowed the performance of cortical speech mapping and the testing of the patient's ability to speak. Although the bispectral index was not used as a guide for the administration of the drugs, its value correlated better with the patient's responsiveness than did the predicted effect-site concentrations of propofol. Side-effects, comprising hypotension, respiratory depression and airway obstruction, were related to rapid increases in drug infusion rates and were easily managed.

Effect of epidural bupivacaine on the relationship between the bispectral index and end-expiratory concentrations of desflurane

We compared the relationship between the bispectral index and end-tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or 10 ml bupivacaine 0.125% with epinephrine 1/800 000 (group B) before induction of anaesthesia with sufentanil (0.15 microgram.kg(-1)) and propofol (2 mg.kg(-1)); muscle relaxation was obtained with cisatracurium (0.2 mg.kg(-1)). Patients lungs were ventilated to maintain end-tidal desflurane at 3% in O2/N2O (50/50) until 5 min after skin incision, followed by two consecutive 10 min periods at end-tidal desflurane 6% and 9%. bispectral index values were recorded before induction, at 3% desflurane before and 5 min after skin incision, and at 6% and 9% end-tidal desflurane. Bispectral index decreased with increasing end-tidal desflurane concentration (ANOVA: p < 0.05). The decrease in bispectral index was significant between pre-induction, 3% and 6% desflurane. No significant difference was observed at 3% desflurane before and after skin incision, or between 6 and 9% desflurane. The relationship between bispectral index and end-tidal desflurane concentration was fitted by a linear regression in each group. No significant difference in bispectral index was observed between the groups at any time. We conclude that bispectral index decreases with increasing desflurane concentration and that this relationship is not affected by epidural 0.125% bupivacaine.

Effects of two calculated plasma sufentanil concentrations on the hemodynamic and bispectral index responses to Mayfield head holder application

The effects of two calculated plasma sufentanil (SUF) concentrations on the hemodynamic and bispectral index (BIS) responses to Mayfield head holder (MH) application were studied in 20 patients scheduled for intracranial surgery. Premedication consisted of hydroxyzine, alprazolam, and atropine given orally 1 hour before surgery. Anesthesia was provided with propofol (PPF) and SUF using a target-controlled infusion device. Patients were randomly assigned to one of two groups according to calculated plasma concentrations: 3 microg/mL(-1) of PPF and 0.5 ng/mL(-1) of SUF in group I (GI) and 3 microg/mL(-1) of PPF and 1 ng/mL(-1) of SUF in group II (GII). The MH was fixed 33.0+/-6.6 minutes (mean +/- SD) after induction. Systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) as well as heart rate (HR) and BIS were recorded 1 minute before pinning (baseline) as well as 1 minute (P1), 2 minutes (P2), and 3 minutes (P3) after pinning. Multivariate repeat-measured analyses of variance were applied to the baseline-subtracted measurements of hemodynamic and BIS values. Groups were compared using the Student's t test, and P < .05 was considered to be statistically significant. Patients' characteristics, baseline hemodynamic values, and BIS values were similar in both groups. A significant overall time effect was observed for all variables, but no significant overall SUF effect was detected. Increases in SAP, MAP, DAP, and HR did not differ significantly between groups. The increase in hemodynamic variables did not exceed 20% of baseline value in either group. In contrast, at P1, the increase in BIS over the baseline value was significantly higher in GI (15.0+/-7.9) than in GII (6.7+/-6.5). In conclusion, MH application was associated with a significant, although not clinically relevant, increase in hemodynamic variables whatever the calculated plasma SUF concentration (0.5 or 1.0 ng/mL(-1)). In contrast, the increase in BIS observed at pinning was significantly higher in patients with the lowest calculated plasma SUF concentrations. This suggests that the BIS response to noxious stimulation is modulated by the analgesic regimen.

Influence of induction of anaesthesia on intubating conditions one minute after rocuronium administration: comparison of ketamine and thiopentone

We compared the effect of thiopentone and ketamine on intubating conditions after rocuronium 0.6 mg.kg-1 in two groups of patients (n = 16 each), aged 21-44 years, undergoing elective surgery. Premedication consisted of alprazolam 1 mg by mouth 1 h before surgery. All patients received midazolam 2 mg intravenously 2 min before intravenous administration of thiopentone 5 mg.kg-1 or ketamine 2.5 mg.kg-1. Muscle relaxation was provided by rocuronium 0.6 mg.kg-1. One minute after rocuronium administration, tracheal intubation was performed within 15 s by a skilled anaesthetist blinded to the treatment group assignment. Intubating conditions were graded as excellent, good, fair or poor on the basis of jaw relaxation, position of vocal cords and diaphragmatic response. Neuromuscular transmission was assessed at the adductor pollicis muscle using a TOF-GUARD monitor. Excellent and good intubating conditions were obtained in 100% of patients in the ketamine group and in 50% of patients in the thiopentone group (p = 0.002). Jaw relaxation was similar in both groups but vocal cord conditions were better and the diaphragmatic response less marked in the ketamine group compared with the thiopentone group (p = 0.002). The degree of neuromuscular block [% decrease of T1, mean (SD)] at the time of intubation was similar: 51.8 (25)% (ketamine group) and 54.3 (23.1)% (thiopentone group). We conclude that ketamine 2.5 mg.kg-1 provides better intubating conditions than thiopentone 5 mg.kg-1 1 min after administration of rocuronium 0.6 mg.kg-1.

Effects of target-controlled anesthesia with propofol and sufentanil on the hemodynamic response to Mayfield head holder application

The effects of target-controlled anesthesia with propofol and sufentanil on the hemodynamic response to Mayfield head holder (MH) application were evaluated in 18 ASA I and II patients undergoing scheduled intracranial surgery. Premedication consisted of hydroxyzine, alprazolam and atropine given orally 1 h before surgery. Anesthesia was provided with propofol and sufentanil using a target-controlled infusion device; constant calculated plasma concentrations of 4 micrograms ml-1 propofol and 0.5 ng ml-1 sufentanil were maintained throughout the study. Muscle relaxation was obtained with atracurium and ventilation was controlled with air/oxygen. The MH was fixed 45 +/- 12 min (mean +/- SD) after induction of anesthesia. Heart rate and systolic, diastolic, and mean non invasive arterial pressure were monitored and recorded 5 min before induction of anesthesia (control), 1 min before MH application (MH-1), at MH application, and 1 and 2 min after MH application. Systolic, diastolic, mean arterial pressure, and heart rate increased significantly during and after MH application when compared with MH-1 values, but remained constantly lower than control. Hemodynamic parameters measured 1 min before MH application were significantly lower than control. The results of the study indicate that target-controlled anesthesia maintained with constant calculated plasma concentrations of 4 micrograms ml-1 propofol and 0.5 ng ml-1 sufentanil prevents the increase in arterial pressure and heart rate beyond control values following MH application but may induce some degree of arterial hypotension in the absence of nociceptive stimulation.

Predictive accuracy of continuous propofol infusions in neurosurgical patients: comparison of pharmacokinetic models

The performance of 10 pharmacokinetic models in predicting blood propofol concentrations was evaluated in patients during neurosurgical anesthesia. Eight patients-ASA category I or II, aged 49 +/- 18-years, weighing 71 +/- 20 kg, and scheduled for routine neurosurgery-were anesthetized with propofol and sufentanil using Ohmeda pumps controlled with a personal computer. Sufentanil was administered as a bolus of 0.3 microgram.kg-1, 5 min before induction of anesthesia, and infused at a constant rate of 0.5 microgram.kg-1.h-1 throughout the study. At induction, propofol was administered as a bolus of 1.5 mg.kg-1 followed by a continuous infusion of 6 mg.kg-1.h-1. During surgery, the propofol infusion rate was deliberately increased by 2 mg.kg-1.h-1 every 15 min up to 12 mg.kg-1.h-1. Arterial blood samples were drawn at the end of each infusion step for measurement of propofol concentrations by high-performance liquid chromatography. Measured propofol concentrations were compared with theoretical concentrations derived from 10 published pharmacokinetic models designed in different clinical settings. Each model has been assessed by calculating the median of the performance error, the median of the absolute performance error, and their 10th and 90th percentiles. Models designed for certain categories, such as children, young, or elderly patients who received propofol as a bolus injection, showed a bad predictive accuracy. The models of Gepts et al. (Anesth Analg 1987; 66:1256-1263, Anaesthesia 1988; 43(suppl):8-13), Tackley et al. (Br J Anaesth 1989;62:46-53), and Cockshott (Postgrad Med J 1985;61:55), derived from healthy patients receiving continuous propofol infusions, provided the best agreement between expected and measured propofol concentrations; they showed bias and inaccuracy lower than 17%. In conclusion, the accurate prediction of blood propofol concentrations from different continuous infusion rates in ASA I or II patients requires the selection of appropriate pharmacokinetic models derived from similar categories of patients and using a similar technique of propofol administration. However, in clinical practice, the selection of a specific set among the appropriate models is balanced by the interindividual variability in blood propofol concentrations adjusted to clinical effects.