[Anesthesic practices in patients with severe postpartum hemorrhage with persistent or worsening bleeding]

Severe postpartum hemorrhage (PPH) is a rare and critical situation which requires fast and well-planned management where close collaboration between obstetricians and anesthesiologists is essential. In case of persisting or worsening bleeding in spite of initially adequate management, the main goal of the anesthesiologist is to maintain hemodynamic stability (fluid resuscitation, transfusion, vasoactive drugs) and optimal respiratory state (oxygenation) and to correct the frequent clotting disorders, whereas the obstetrician and/or the radiologist have to achieve definitive hemostasis. Assessment of the severity of PPH is determined from: quantity of blood loss and/or duration of bleeding, difficulty in maintaining a correct hemodynamic state in spite of active vascular fluid resuscitation, need for vasoactive therapy and transfusion, occurrence and worsening of clotting disorders. Continuous drip Sulprostone requires close clinical surveillance and continuous monitoring (electrocardiography, non-invasive blood pressure monitor, pulse oximetry). When this treatment does not enable sufficiently rapid control of the bleeding (consensus = within 30 minutes), invasive therapy (arterial embolization, vascular ligation even hysterectomy) should be started promptly. When the bleeding continues despite aggressive medical treatments, general anesthesia (even if an epidural catheter is already in place) is needed to proceed with the invasive surgical procedure. This anaesthesia of a "full stomach" patient justifies a rapid-sequence induction with cricoid pressure and intubation. The risk is particularly high in case of hemorrhagic shock. Angiographic embolization should be carried out in an angiography suite which must be equipped for this kind of situation (anesthesia and resuscitation material, adapted monitoring). A member of the anesthesia team must be present throughout this procedure. At best, a multidisciplinary team, specially trained for this purpose, including obstetrician, anesthesiologist, radiologist and biologist should be available. When one or several invasive treatments were necessary to control the bleeding, it is recommended to transfer the patient to a specialized unit (intensive care unit or recovery room).

[Efficacy and safety of inhalation premixed nitrous oxide and oxygen for the management of procedural diagnostic pain in neuropediatrics]

AIM

We studied the use of premixed nitrous oxide and oxygen in 80 patients with neurologic diseases.

PATIENTS AND METHODS

Mean ages ranged 10 +/- 5 yrs. Twenty-three patients (29%) were mentally retardated among which 17 of them presented with severe epilepsy. Painful procedures consisted of: lumbar punctures (80%), intravenous access (7), gastric endoscopy (6), skin biopsy (4), gastrostomy tube management (3). High-risk children were continuously monitored using ECG, non invasive blood pressure and transcutaneous oxygen saturation. We studied acceptation of the inhalation, vital signs, satisfaction of children, parents, medical and nursing staffs; side effects were compared with a group of healthy children undergoing venous access before induction of anesthesia.

RESULTS AND DISCUSSION

Acceptation increased with age. No significant changes in vital signs variables were observed. Satisfaction rate regarding the method was 88% for all children, parents, physicians and nurses. No serious undesirable event (as respiratory depression, seizure, inhalation of gastric content) occurred in these patients. The more frequent side-effects were: drowsiness during and after inhalation (35 and 9% respectively in the handicapped patients); nausea and vomiting (8%), headaches (3%), were more frequent than reported in literature but there were 25% of meningitis among our patients.

CONCLUSION

Premixed nitrous oxide and oxygen was effective for reducing procedural pain and anxiety in children with neurological disorders, even in severely handicapped patients, with minor side-effects.

Preoperative coagulation tests in former preterm infants undergoing spinal anaesthesia

BACKGROUND

Clinical history is insufficient to detect disorders of haemostasis in infants aged less than 1 year and laboratory coagulation testing is recommended in infants before perimedullar anaesthesia.

METHODS

We designed a retrospective study to assess the preoperative coagulation tests [activated partial thromboplastin time (aPTT), prothrombin time, platelet count] performed in 141 former preterm infants who underwent spinal anaesthesia for elective inguinal hernia repair. All the infants had recovered from any significant medical event (necrotizing enterocolitis, intracranial haemorrhages, transfusions of blood products, sepsis, etc.) when they were scheduled for surgery.

RESULTS

Mean values for aPTT were frequently abnormal (60.4%) in infants with a postconceptional age of less than 45 weeks. No complication related to the puncture or abnormal perioperative bleeding was detected.

CONCLUSIONS

Other coagulation tests should be evaluated to assess the coagulation status in infants with a postconceptional age of less than 45 weeks.

[Evaluation of antibacterial filters for peridural obstetrical anesthesia]

OBJECTIVES

To assess the antibacterial efficiency of filters used in obstetrics when epidural top-ups are performed.

STUDY DESIGN

Observational prospective study.

PATIENTS AND METHODS

We aseptically collected 201 antibacterial filters that had been used for top-ups with ropivacaine +/- sufentanil for epidural analgesia during labour. We flushed them first with 2 mL of saline and then with 2 mL of a solution containing 1.5 x 10(6) Staphylococcus epidermidis/mL. The filtrates were incubated at 37 degrees C for 72 h. Number of top-ups and duration of epidural analgesia are expressed as median (extremes).

RESULTS

3 (1-10) top-ups were performed for labour analgesia over a period of 6.5 h (1.8-18). After filtering, all the solutions were found to be sterile. Especially, when using Staphylococcus epidermidis solutions, bacteria were not found beyond any filter. These results suggest the integrity of the filter membrane after several boluses. No infection related to epidural analgesia was reported.

CONCLUSION

Antibacterial filters provide a good protection against a potentially contaminated procedure during epidural top-ups.

Dose of prophylactic intravenous ephedrine during spinal anesthesia for cesarean section

STUDY OBJECTIVE

To compare the incidence of maternal hypotension associated with spinal anesthesia for cesarean section when 10-, 15-, or 20-mg prophylactic boluses of intravenous (IV) ephedrine are used.

DESIGN

Prospective observational study.

SETTING

Teaching hospital.

PATIENTS

108 women admitted for elective cesarean section.

INTERVENTIONS

Spinal anesthesia was performed using hyperbaric bupivacaine 10 mg, sufentanil 2 microg, and morphine 0.2 mg (volume 4 mL). Ephedrine (10, 15, or 20 mg) was administered 2 minutes after the intrathecal injection. Maternal blood pressure was checked every 2 minutes. Hypotension was promptly treated with 5-mg ephedrine boluses.

MAIN RESULTS

Incidence of hypotension was significantly higher in women receiving a 10-mg prophylactic dose of ephedrine than in those receiving either a 15-mg or a 20-mg prophylactic dose of ephedrine [23/36 in the 10-mg ephedrine group vs. 13/36 and 10/36 in the 15-mg and 20-mg ephedrine groups, respectively (p< 0.05)].

CONCLUSION

In the conditions of this study, a single bolus of IV ephedrine with doses of either 15 or 20 mg decreased significantly the incidence of maternal hypotension as compared to a single 10-mg bolus of ephedrine.

Engraftment of autologous retrovirally transduced hepatocytes after intraportal transplantation into nonhuman primates: implication for ex vivo gene therapy

The main impediment to effective ex vivo liver gene therapy of metabolic diseases is the lack of experimental work on large animals to resolve such important issues as effective gene delivery, cell-processing techniques, and the development of appropriate vectors. We have used a nonhuman primate, as a preclinical model, to analyze the limiting steps of this approach using recombinant retroviruses. Seven monkeys (Macaca fascicularis) underwent the complete protocol: their left liver lobe was resected, a catheter was placed in the inferior mesenteric vein and connected to an infusion chamber, and the hepatocytes were isolated, cultured, and transduced with a retroviral vector containing the beta-galactosidase gene. The hepatocytes were harvested and returned to the host via the infusion chamber. Biopsies were taken 4-40 days later. No animal was killed in the course of the experiments. They all tolerated the procedure well. We have developed and defined conditions that permit the proliferation and transduction of up to 90% of the plated hepatocytes. A significant proportion of genetically modified cells, representing up to 3% of the liver mass, were safely delivered to the liver via the chamber. Polymerase chain reaction analysis detected integrated viral DNA sequences and quantitative analysis of the in situ beta-Gal-expressing hepatocytes indicated that a significant amount of transduced hepatocytes, up to 2%, had become integrated into the liver and were functional. These results represent substantial advances in the development of the ex vivo approach and suggest that this approach is of clinical relevance for liver-directed gene therapy.

[Treatment with danaparoid during pregnancy for a woman with a cutenous allergy to low-molecular-weight heparin]

The authors describe a case of heparin-induced skin reaction due to two preparations of low molecular weight heparin in a pregnant woman. The main characteristics of heparin-related cutaneous allergy are reported. The use of an heparinoid, usually indicated for patients with heparin-induced thrombocytopenia, appeared to be efficient and safe for the mother and her fetus. An epidural analgesia was performed for labor analgesia, 24 hours after the last injection of danaparid of sodium.

[Nosocomial infections in mother and child: specific risks in the labour ward]

Nosocomial infection is a frequent and potentially lethal complication in obstetrics. The incidence of this complication may be underscored and an accurate surveillance system must be used in each obstetrics unit for infection control. This surveillance system should also identify the patients at risk for infection in order to improve prevention efforts. beta-lactam-sensitive streptococcus is often involved in obstetrical infections and a short antibio-prophylaxis is indicated in most obstetrical procedures. Disinfection strategy, guidelines for clinical practice and control charts should be established in each obstetrics unit to prevent nosocomial infections.

Central venous catheter placement in children: evaluation of electrocardiography using J-wire

Misplacement of a central venous catheter may lead to myocardial perforation and dysrhythmia. Atrial electrocardiography (ECG) through a saline column is an effective but complex method to determine the accurate location of catheters. We evaluated a simplified variant of this technique using the guidewire as an internal electrode in 23 children (5-16 years old) undergoing spinal surgery. Catheters were placed using a Seldinger technique after jugular or subclavian venous puncture. Each time the operator recognized the atrial signal, the catheter was found to be correctly placed on the chest radiograph (20/23). In three patients, the atrial signal was not obtained. A technical error was responsible in one case whereas the two others were related to aberrant migrations of the catheter either into a subclavian vein or into the pleura. In this latter case, the complication was unrecognized on the first radiograph despite malposition having been predicted by atrial ECG. We conclude that a method using atrial ECG guidance is sensitive and specific, and may be an alternative to the classical chest radiograph to detect accurate placement of central venous catheters in children.

[Dural taps in peridural analgesia for labor: management by French anesthesiologists in 1997]

OBJECTIVES

To assess prophylactic and curative managements of dural taps occurring during the setting of epidural analgesia (EA) for labour.

STUDY DESIGN

Nationwide French retrospective survey.

PATIENTS AND METHODS

From April to July 1997, a questionnaire was sent to 799 French obstetrical units located in both teaching and non-teaching public hospitals and private institutions.

RESULTS

Answers were obtained from 267 units (response rate of 33%). Although management of dural taps was similar in 52% of the institutions, only 8% had produced a written protocol. After a dural puncture, EA was still performed in 95% of the units, but usually in another interspace (87%). Large oral fluid intake was the most frequent prophylactic measure (81%). To prevent postdural puncture headache (PDPH), bed rest was largely used (76%) and lasted 24 hours in 46% of the institutions. Prophylactic epidural blood patch (EBP) was performed in 14% of the units. To treat PDPH, a majority of anaesthesiologists performed an EBP (92%) and most of them after a delay of 48 hours (62%). Intravenous and oral caffeine was used in 31 and 24% of the units respectively. Prior to EBP, coagulation status was assessed in about 20% of the units and blood culture in less than 3%. In 65% of the units the injection of EBP was discontinued when the patients felt backache. A large range of volumes were injected, but usually less than 20 mL were administered (81%). In 60% of the units the patients were discharged home after an overnight stay in the hospital. If the first EBP failed, a second one was performed in 61% of the cases.

CONCLUSION

Management of dural taps occurring after EA for pain relief in labour differs widely from one French obstetrical unit to another.

In utero allotransplantation of retrovirally transduced fetal hepatocytes in primates: feasibility and short-term follow-up

In utero allotransplantation of fetal hepatocytes into a preimmune fetus could be used in early treatment of many inherited hepatic metabolic diseases. This study was designed to assess the tolerance to hepatocyte transplantation and to test the feasability and toxicity of such an injection in a primate model. Fetal hepatocytes were obtained from two 120-day-old Macaca mulatta fetuses and cryopreserved. They were thawed, cultured in vitro, and transduced with a recombinant retrovirus expressing beta-galactosidase. Transduction efficiency was 75-85%. Three unrelated fetuses (90, 100, and 104 days old) were each given 1-2 x 10(7) transduced cells via the umbilical vein. This caused vasospasm and severe bradycardia. Two fetuses died in the 48 hours after transplantation; the third survived and was killed at the end of gestation. No evidence of the infused cells was found. Three fetuses (90 days old) were, therefore, given 3-4 10(7) hepatocytes by direct intrahepatic injection. All the fetuses survived without side effect. Donor cells were not apparent from histochemical staining and PCR reactions. There was no evidence of inflammatory reaction. These findings indicate that the protocole could be improved by increasing the number of transplanted cells and using specific hepatic promoters in the retroviral vectors to achieve an effective postnatal chimerism.

[Prolonged curarization with suxamethonium in a four-week old infant]

A case of a 28-day-old infant who developed suxamethonium apnoea is described. He was found to be homozygous for atypical cholinesterase. Main characteristics of this disorder are reviewed. Other causes of prolonged apnoea in infants recovering from anaesthesia for surgery of pyloric stenosis are discussed.

[Evaluation of hemostasis before obstetrical epidural anesthesia: a survey in 435 French obstetric departments]

OBJECTIVES

To specify by which means French anaesthesiologists evaluate the haemostasis profile of pregnant women before epidural analgesia.

STUDY DESIGN

Nationwide retrospective survey.

MATERIAL

Questionnaire sent of 847 French obstetrical units.

METHODS

Comparison of categorical qualitative parameters using a chi 2 test.

RESULTS

Answers from 435 centres, including 1,834 anaesthesiologists, performing 227 x 10(3) epidurals for 411 x 10(3) deliveries/year were obtained. A preanaesthetic clinical assessment was performed systematically in two out of three units, and blood samples for PT, aPTT and platelet count were taken in more than 90% of the centres. These laboratory examinations were often made during the 9th month of pregnancy (74%). For more than one-third of the anaesthesiologists, biological data are not essential before epidural puncture. In addition, the lower limits considered as being safe before epidural puncture were highly variable between the teams.

CONCLUSIONS

Coagulation laboratory tests are almost always ordered before epidural obstetrical analgesia in France. The rationale to perform them is not always related to pregnancy induced haemostatic changes. Therefore, this problem should be clarified by a consensus conference for both practical and economical reasons.

Pre-anaesthetic assessment of coagulation abnormalities in obstetric patients: usefulness, timing and clinical implications

The usefulness and optimal timing of laboratory coagulation tests before obstetric extradural analgesia are controversial. Moreover, the significance of mild coagulation abnormalities during pregnancy remains unclear. We have assessed the reliability of coagulation tests performed several weeks before delivery as predictors of coagulation abnormalities during labour. Platelet count, plasma fibrinogen concentration, prothrombin time (PT) and activated partial thromboplastin time (aPTT) were sampled in 797 women during the ninth month of pregnancy and checked during labour. Platelet count was less than 100 x 10(9) litre-1 for 11 women during labour. Only three had been detected by the first sample. Platelet count less than 100 x 10(9) litre-1 or fibrinogen concentration less than 2.9 g litre-1 during labour were associated with an increase in the incidence of postpartum haemorrhage (odds ratio = 19.7). We conclude that a platelet count several weeks before delivery was not reliable in predicting thrombocytopenia during labour and that women with mild coagulation abnormalities in early labour may need special attention regarding the risk of postpartum haemorrhage.

Continuous extradural infusion of ropivacaine 2 mg ml-1 for pain relief during labour

We have assessed the dose-response relationship of a solution of ropivacaine 2 mg ml-1, given as a continuous extradural infusion to women in labour. A total of 133 parturients were allocated randomly to one of four groups to receive a fixed rate ropivacaine infusion of 4, 6, 8 or 10 ml h-1 with additional bolus doses as necessary. Contraction pain, quality of analgesia, sensory block, motor block and neonatal Apgar scores were assessed. There were no significant differences between groups in terms of analgesia or motor block, although significantly more bolus doses were required by the group receiving 4 ml h-1 (P < 0.05 compared with the other groups), and a significantly higher total dose of ropivacaine was administered to the 10-ml h-1 group compared with the 6-ml h-1 group (P = 0.044). There were no significant differences between groups in terms of obstetric or neonatal outcome. We conclude that ropivacaine 2 mg ml-1 was effective and well tolerated when given as a continuous extradural infusion at 6-8 ml h-1 and may be used as the sole analgesic during labour.

Preclinical studies for cell transplantation: isolation of primate fetal hepatocytes, their cryopreservation, and efficient retroviral transduction

Fetal hepatocytes are an attractive target for in utero cellular transplantation. Their use could provide a very efficient way for implanting normal or transduced cells into the livers of affected fetuses. Marking cells with recombinant retroviruses is a powerful tool for evaluating the chimerism of grafted animals. The technique relies on the ex vivo transduction efficiency of the engrafted cells. We have isolated fetal primary hepatocytes from nonhuman primates. The cells were cultured and transduced with a retroviral vector carrying the Escherichia coli beta-galactosidase gene. Optimal gene transfer efficiency was obtained 48-60 hr after plating and was as high as 90%. Cryopreservation had little effect on cell viability and infectivity: The viability of thawed hepatocytes remained high (75-85%) and the infection efficiency was identical to that of freshly isolated cells. Efficient ex vivo retroviral gene transfer into fetal hepatocytes provides an appropriate system for testing allogenic grafting and for modifying immunogenicity of engrafted cells. These results open up new perspectives for cell transplantation through cell banking.

[Acute fetal distress. The anesthesiologist's point of view]

Foetal distress is a non-specific and imprecise diagnose sometimes associated with surgical delivery of a normal newborn. As this type of delivery is usually considered urgent, emergent anaesthesia is required. General anaesthesia is usually chosen in these cases because it is the quickest anaesthetic technique and because of fears concerning the haemodynamic consequences of regional techniques. Maternal risks of general anaesthesia which is the leading cause of anaesthesia-related maternal mortality (difficult intubation and Mendelson's syndrome) but also neonatal consequences (increased need for neonatal resuscitation) have challenged this policy. Indeed, spinal anaesthesia and extension of a pre-existing epidural analgesia are more and more used during emergency Caesarean section. A better evaluation of the patient's problems based upon a pre-anaesthetic outpatient visit during the last trimester of pregnancy allows a more rational approach to meet the patient's requirements should an emergency. Caesarean section be necessary. For example, a "prophylactic" epidural instituted soon after the beginning of labour may be lifesaving in a patient with obvious signs of difficult intubation. A clear definition of safe standards of equipment and practices either to prevent. Mendelson's syndrome or to cope with a failed intubation drill is of greatest importance. Finally, comprehensive communication between the anaesthetic and obstetrical teams is one of the most useful ways to facilitate safer approach of the management of obstetric emergencies studies. Caesarean section for foetal distress.

Parturient's posture during epidural puncture affects the distance from skin to epidural space

STUDY OBJECTIVE

To assess the factors affecting the distance from skin to epidural space.

DESIGN

Prospective observational study of consecutive cases over a 2-year period.

SETTING

Inpatient obstetric unit in a French university hospital.

PATIENTS

2,123 consecutive term parturients who received epidural anesthesia for cesarean section or epidural analgesia for labor and vaginal delivery.

INTERVENTIONS

At the time of epidural puncture, the interspace used and the patient's posture (sitting or left lateral decubitus) were recorded, and the distance from the skin to the epidural space (DS-ES) was measured to the nearest 0.5 cm using a marked epidural needle.

MEASUREMENTS AND MAIN RESULTS

The relationship between patient factors [height, weight, body mass index (BMI; weight/height2), presence of scoliosis] and technical factors (interspace, patient's posture at puncture) versus DS-ES was investigated using multiple regression analysis. DS-ES correlated positively with the parturient's weight and BMI. In addition, DS-ES was significantly greater when epidural puncture was performed in the lateral position as compared with the sitting position.

CONCLUSION

Both the patient's weight and position during epidural needle placement are important factors influencing DS-ES. A change from the sitting to the lateral position may increase DS-ES, causing catheter dislodgment and consequent inadequate analgesia. Clinical studies relating DS-ES to inadequate analgesia must take these factors into account.

Sevoflurane elimination kinetics in children

We compared the rates of elimination of sevoflurane and halothane in 29 children, aged between one and seven years, undergoing ambulatory anaesthesia. Analgesia was provided by fentanyl and muscle relaxation by atracurium. Anaesthesia was maintained by inhalation of one MAC of either sevoflurane or halothane, based on an equipotent concentration of each agent for the age of the child. Following simultaneous discontinuation of N2O and the inhalational agent, the equation describing N2O washout was identical in the presence of halothane and sevoflurane, showing that there was no effect of the volatile agent on the rate of N2O elimination. The elimination of sevoflurane and N2O give similar types of equations. Halothane elimination gives a logarithmic type of equation, showing a slower release, corresponding to residual tissue content.

Post partum headache after epidural analgesia without dural puncture

In order to improve our knowledge of post partum headache, during a two-year period we studied a large population of pregnant patients of our institution using a four-stage process including two questionnaires (the first at 12-15 weeks' gestation and the second in the first week after delivery), a pre-anesthetic visit at 36 +/- 2 weeks' gestation and a computer printout obtained at delivery. Of 1058 patients for whom records were complete and who had epidural analgesia during labor not complicated by dural puncture, 128 (12.1%) complained of post partum headache. In patients who did not receive epidural analgesia, the incidence of post partum headache tended to be higher (15.2%). However, because of the low response rate (27.1%) and the low absolute number of patients with headache (27) in the non-epidural group, statistical comparison was not possible. Data from the medical history or from the current pregnancy as well as data obtained during delivery (maternal and fetal-neonatal) were not significantly different between those patients free of pain and those presenting with headache, except for a history of migraine and pregnancy-induced hypertension which were both associated with an increased risk of post partum headache. These risk factors should be considered in both clinical studies and obstetric malpractice claims.

Addition of oral clonidine to postoperative patient-controlled analgesia with i.v. morphine

Using a randomized, double-blind, placebo-controlled design, we have investigated, in 40 patients undergoing major abdominal surgery, the effect of oral clonidine 300 micrograms, 1 h before and 12 h after surgery on postoperative morphine requirements (evaluated by PCA). During the 24 h of the study, pain scores measured every 6 h did not differ significantly. Morphine requirements tended to be reduced in the clonidine group but the difference was not significant. There were no significant differences also in mean arterial pressure, ventilatory frequency and the incidence of pruritus and nausea. Heart rate was significantly lower until 18 h after surgery and sedation was significantly more pronounced in patients receiving clonidine. We cannot recommend routine oral administration of clonidine before surgery to improve postoperative analgesia.

Anaesthesia for caesarean section in a patient receiving high dose amiodarone for fetal supraventricular tachycardia

We report the anaesthetic management of a Caesarean section in a woman treated with high dose amiodarone for fetal supraventricular tachycardia. Most of the interactions between anaesthesia and amiodarone therapy previously reported were observed during general anaesthesia. We therefore chose epidural anaesthesia using incremental doses of lignocaine 2% with adrenaline and fentanyl. This technique appeared to be safe, but since severe refractory vasodilation with hypotension may occur, potent vasopressor agents should be immediately available.

[Use of Diprivan in gynecology]

1. Propofol as an induction agent At a dose of 2 to 2.5 mg.kg-1, as a bolus injection over 30 to 60 seconds, for gynaecological procedures of short duration (abortion, D and C), propofol can be characterized as follows when compared with other induction agents: ADVANTAGES OVER METHOHEXITONE AND ETOMIDATE: decreased incidence of hiccups and abnormal movements, increased quality of induction, similar to that obtained with thiopentone, decreased postoperative nausea and vomiting. ADVANTAGES OVER THIOPENTONE: shorter recovery period, more rapid recovery of consciousness and orientation. DISADVANTAGES WHEN COMPARED WITH THIOPENTONE: more frequent pain at the injection site, however its prevention is possible, more frequent apnoea, but may be avoided by slowly injecting the drug, higher cost. The main advantage of propofol over thiopentone (shorter recovery period), makes day-case gynaecological procedures one of its major indications. This concerns young, healthy women, whose professional and family lives are important and who may benefit from minimal disruption in their way of life. 2. Propofol as a maintenance agent Propofol is given as a continuous infusion at a dose ranging from 6 to 12 mg.kg-1.h-1 for maintenance of prolonged procedures (abdominal surgery, hysterectomy) and can be characterized as follows with respect to halogenated anaesthetics: ADVANTAGES OVER ENFLURANE AND ISOFLURANE: decreased postoperative nausea and vomiting, increased recovery scores (1st hour). COMPARED WITH DESFLURANE: shorter induction time than desflurane, less respiratory problems at induction, similar recovery period, same incidence of nausea and vomiting. The administration of propofol for maintenance of anaesthesia has the main advantage of reducing the incidence of postoperative nausea and vomiting when compared to conventional halogenated anaesthetics. Respective costs of the various techniques, using propofol or the new halogenated anaesthetics, may be a criterion for choice in the future.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilatory effects of epidural clonidine during the first 3 hours after caesarean section

Many authors have shown the analgesic efficacy of 150-800 micrograms of epidural clonidine in the postoperative period. Its use as an analgesic after caesarean section has recently been studied with higher dosages (400-800 micrograms). Our study aimed at assessing the analgesic and ventilatory effects of two smaller doses of epidural clonidine (150 and 300 micrograms), which were compared to the effects of 10 mg of parenteral morphine (M) during the first 3 h after caesarean section. The duration of the analgesic effect was longest with 150 micrograms of epidural clonidine. Arterial blood pressure decreased from 30 min after the injection to the end of the study in both epidural clonidine groups. A marked sedation was observed in patients receiving 300 micrograms of epidural clonidine and was frequently associated with snoring, obstructive apnoea and episodes of arterial oxygen desaturation. We conclude that 150 micrograms of epidural clonidine provides better and longer analgesia after caesarean section than 10 mg of parenteral morphine, and seems preferable to higher doses (300 micrograms) in this setting, since 300 micrograms of epidural clonidine may produce unacceptable respiratory obstructive disturbances.

Neonatal pattern of breathing during active and quiet sleep after maternal administration of meperidine

The aim of this study was to reappraise the effects of maternal meperidine administration on breathing pattern during the first hours of life taking into account the state of alertness. Because breathing instability is more pronounced during active sleep, we hypothesized that meperidine administration might create a greater risk for respiratory instability during active sleep, the prominent sleep state in newborns. We studied eight full-term, healthy newborns whose mothers had received a continuous i.v. infusion of meperidine (81 +/- 9 mg) that was terminated 5.5 +/- 2.1 h before delivery. These infants were compared with a control group of eight full-term newborns whose mothers did not receive any opioids. In both groups, all babies were delivered vaginally after a normal labor and had Apgar scores of 9 or 10 at 1 and 5 min. Neonatal gastric secretion and maternal venous and umbilical venous blood were sampled at delivery for determination of meperidine concentration. From 60 to 300 min after delivery, behavioral sleep states and thoracic and abdominal movement as well as transcutaneous arterial oxygen saturation (SaO2) were monitored continuously. The number of apneic spells lasting more than 3 s during 100 min of recording and the percentage of time with SaO2 below 90% in each sleep state were recorded. During quiet sleep, all respiratory variables were similar in both groups. During active sleep, there were significantly more apneic episodes (37.1 +/- 25.1 versus 11.2 +/- 13.9) and a higher percentage of time with SaO2 less than 90% (14.3 +/- 16.7% versus 1.3 +/- 1.5%) in the meperidine group than in the control group (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[Fetal and neonatal effects of perimedullary opioids used in obstetrical anesthesia]

The use of spinal or epidural narcotics is more and more frequent in obstetric patients since it enhances the analgesia induced by local anesthetics. However, specific information regarding their fetal and neonatal effects is rare. Fetal effects are mainly dependent on the respiratory and hemodynamic maternal effects, and thus usually limited when usual low dosages of intraspinal narcotics are used. Neonatal respiratory depression, which is the main neonatal risk, has not been fully studied. In contrast, the evaluation of Apgar and neurobehavioral scores, performed for all the narcotics used, shows little changes when low dosages are used. However, the use of larger dosages epidurally is associated with an increased frequency of low neurobehavioral scores. Therefore, the use of low dosages of epidural narcotics is recommended since there is little available information about the risk of neonatal respiratory depression and no clear maternal advantage of higher dosages.

[Passive compliance of the total respiratory system in newborn infants born by cesarean section]

The compliance of the total respiratory system (CRS) was measured by the occlusion technique: a) at H1-H2, H6-H7 and D3-D4 in 8 full-term newborns after cesarean section; b) at H1-H2 and H6-H7 in 6 full-term newborns delivered vaginally and at D3-D4 in 10 full-term newborns delivered vaginally. At H1-H2 respiratory frequency measured by inductive plethysmography was not significantly different between newborns after cesarean section (60 +/- 6 c/min) and newborns delivered vaginally (53 +/- 16 c/min). CRS normalized for body weight was not significantly different between newborns after cesarean section and those delivered vaginally at H1-H2 (0.6 +/- 0.1 vs 0.7 +/- 0.1 ml/cmH2O/kg) and at H6-H7 (0.7 +/- 0.1 vs 0.8 +/- 0.3 ml/cmH2O/kg). At D3-D4, CRS was significantly greater than at H6-H7 in newborns after cesarean section (1.1 +/- 0.2 ml/cmH2O/kg, p less than 0.001) and in newborns delivered vaginally (1 +/- 0.1 ml/cmH2O/kg, p less than 0.02). We conclude that in newborns after cesarean section without tachypnea, the evolution in CRS is similar to that in newborns delivered vaginally.

Alkalinization of 0.5% lidocaine for intravenous regional anesthesia

Although remaining a controversial issue, alkalinization of lidocaine or bupivacaine may shorten the time to onset and increase the duration of the sensory block. The aim of this study was to evaluate the effect of pH adjustment on the sensory and motor blocks during intravenous regional anesthesia (IVRA) with lidocaine. Thirty-one patients scheduled for minor hand surgery performed under IVRA were randomized into two groups: Group 1 (n = 14): 1% lidocaine, 3 mg/kg, diluted with the same volume of physiological saline solution (pH = 6.63 +/- 0.05), and Group 2 (n = 17): 1% lidocaine, 3 mg/kg, diluted with the same volume of 1.4% sodium bicarbonate (pH = 7.34 +/- 0.05). final concentration of lidocaine was thus 0.5% in both groups. Sensory block was assessed by pinprick every 2 minutes in areas corresponding to six terminal nerves: ulnar, median, radial, musculocutaneous, medial cutaneous nerve of arm and intercostobrachial, and medial cutaneous nerve of forearm. The time between release of tourniquet (at the end of surgery) and appearance of pain was recorded. Motor blockade was evaluated by asking the patient to squeeze strongly a blood pressure cuff previously inflated to 40 mmHg. This maneuver was performed before and every 2 minutes after injection. No statistical differences were found between the two groups whatever the parameter studied. In conclusion, there is no advantage (over plain solutions) to using pH-adjusted lidocaine during IVRA for hand surgery.

Ventilatory response to CO2 following intravenous ketamine in children

The effects of intravenous ketamine (bolus of 2 mg.kg-1 followed by a continuous infusion at a rate of 40 micrograms.kg-1.min-1) on ventilatory response to carbon dioxide were studied in nine children ranging in age from 6 to 10 yr and in weight from 20 to 48 kg. Ketamine did not affect resting respiratory rate, tidal volume, end-tidal CO2 tension (PETCO2), or minute ventilation. Five minutes after the ketamine bolus, the slope VE/PETCO2 decreased significantly (P less than 0.05) from 1.71 +/- 0.47 to 1.05 +/- 0.23 1.min-1.mmHg-1 (mean +/- SD). After 30 min of continuous iv ketamine infusion, the slope returned to 1.65 +/- 0.44 1.min-1.mmHg-1, a significantly higher value (P less than 0.05) compared with the nadir and not significantly different from control. The minute ventilation at a PETCO2 of 60 mmHg decreased from 824 +/- 98 to 626 +/- 26 ml.kg-1.min-1 5 min after iv ketamine, and remained depressed (640 +/- 125 ml.kg-1.min-1 P less than 0.05) throughout the 30-min ketamine infusion. In addition, the slope VT/PETCO2 and the VT 60 did not change during the study; nonetheless, the slope f/PETCO2 and the f 60 decreased significantly following iv bolus ketamine, and the f 60 remained significantly decreased following ketamine infusion. The authors conclude that clinically useful doses of iv ketamine significantly alter ventilatory control in children.

The respiratory effects of isoflurane, enflurane and halothane in spontaneously breathing children

The respiratory effects of halothane, isoflurane and enflurane were assessed during nitrous oxide anaesthesia (N2O 50%) in three groups of unstimulated, spontaneously breathing children who weighed 10-20 kg and were aged 1-6 years. Respiratory variables were measured or calculated from capnographic and pneumotachographic recordings at three multiples of minimal alveolar concentration (MAC). The slope of the carbon dioxide response was measured. Similar increases in end tidal carbon dioxide were found for the three agents at each MAC multiple, and similar decreases in tidal volume and in the slope of the ventilatory response to carbon dioxide. A dose-related tachypnoea occurred with halothane and a significant decrease in the duration of inspiration and the duration of each breath at the deepest level of anaesthesia. A significant increase in both these times occurred with enflurane, and a decrease in respiratory rate. No change in respiratory rate occurred with isoflurane at increasing alveolar concentrations whereas at each level of anaesthesia inspiratory time was significantly reduced.