Attenuation of the pressor response to tracheal intubation in hypertensive proteinuric pregnant patients by lignocaine, alfentanil and magnesium sulphate

Guidelines for the management of women with severe pre-eclampsia

OBJECTIVE

To provide national guidelines for the management of women with severe pre-eclampsia.

DESIGN

A consensus committee of 26 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised.

METHODS

The last SFAR and CNGOF guidelines on the management of women with severe pre-eclampsia were published in 2009. The literature is now sufficient for an update. The aim of this expert panel guidelines is to evaluate the impact of different aspects of the management of women with severe preeclampsia on maternal and neonatal morbidities separately. The experts studied questions within 7 domains. Each question was formulated according to the PICO (Patients Intervention Comparison Outcome) model and the evidence profiles were produced. An extensive literature review and recommendations were carried out and analysed according to the GRADE® methodology.

RESULTS

The SFAR/CNGOF experts panel provided 25 recommendations: 8 have a high level of evidence (GRADE 1+/-), 9 have a moderate level of evidence (GRADE 2+/-), and for 7 recommendations, the GRADE method could not be applied, resulting in expert opinions. No recommendation was provided for 3 questions. After one scoring round, strong agreement was reached between the experts for all the recommendations.

CONCLUSIONS

There was strong agreement among experts who made 25 recommendations to improve practices for the management of women with severe pre-eclampsia.

Effects of magnesium sulphate on the onset time of rocuronium at different doses: a randomized clinical trial

Background and aims

Rocuronium may provide excellent onset time, but high doses are required for effective action. Several strategies have managed to shorten rocuronium onset time, including the use of Magnesium Sulphate (MgSO₄).

Methods

One hundred and eighty patients were randomized into six groups according to rocuronium dose received (0.3, 0.6 or 1.2 mg.kg^-1) and the administration of saline or MgSO⁴ (60 mg.kg^-1). Correlations between tissue perfusion and rocuronium onset time was determined by variations in perfusion index.

Results

Median (quartiles) rocuronium onset times were 85.5 (74.0–92.0); 76.0 (52.0–87.0) and 50.0 (41.0–59.5) seconds for 0.3, 0.6 mg.kg^-1 and 1.2 mg.kg^-1 doses, respectively. MgSO₄ decreased rocuronium onset at doses of 0.3 mg.kg^-1 (60.0 [48.0–74.3] seconds) and 0.6 mg.kg^-1 (44.0 [39.0–49.0] seconds) but not at 1.2 mg.kg^-1 (38.0 [33.5–56.3] seconds) (p < 0.001). Perfusion index variations in groups that received MgSO₄ were greater than in controls. A negative correlation between shorten onset and increased perfusion index was observed in rocuronium doses of 0.3 mg.kg^-1 (r = -0.50; p < 0.001) and 0.6 mg.kg^-1 (r = -0.424; p < 0.001), but not for 1.2 mg.kg^-1 dose (r = -0.25; p = 0.07).

Conclusion

MgSO₄ reduces rocuronium onset time at doses of 0.3 mg.kg^-1 and 0.6 mg.kg^-1 being that the latter has a similar effect when compared to the dose of 1.2 mg.kg^-1, with or without the use of MgSO₄.

Trial registry at

http://www.ensaiosclinicos.gov.br/

Registry Number

RBR-96CY3K

Pharmacological strategies to prevent haemodynamic changes after intubation in parturient women with hypertensive disorders of pregnancy: A network meta-analysis

Objective : This network meta-analysis (NMA) aimed to determine the relative efficacy and safety of pharmacological strategies used to mitigate haemodynamic instability by intubation for general anaesthesia in hypertensive parturient women undergoing caesarean section. Methods : We considered randomised controlled studies comparing the effects of pharmacological strategies used to alleviate haemodynamic instability during intubation in parturient women with hypertensive disorders of pregnancy. The primary endpoints were maximum blood pressure and heart rate after intubation, and secondary endpoints were the Apgar scores at 1 and 5 min. NMA allowed us to combine direct and indirect comparisons between strategies. Results : Twelve studies evaluating nine pharmacological strategies in 619 patients were included. According to the surface under the cumulative ranking curve, the maximal mean arterial pressure was lowest for high-dose remifentanil (99.4%) followed by nitroglycerin (73.6%) and labetalol (60.9%). The maximal heart rate was lowest for labetalol (99.9%) followed by high dose of remifentanil (81.2%) and fentanyl (61.6%). Apgar score at 1 min was higher with low-dose than with high-dose remifentanil (mean difference, 0.726; 95% confidence interval, 0.056 to 1.396; I2=0.0%). Conclusions : High-dose remifentanil produces minimum blood pressure changes, while labetalol is most effective in maintaining normal heart rate in parturient women with hypertensive disorders of pregnancy during caesarean section under general anaesthesia.

Phaeochromocytoma Causing Acute Pulmonary Oedema during Emergency Caesarean Section

We report a case of severe acute pulmonary oedema following induction of general anaesthesia for emergency caesarean section. After several hours of aggressive resuscitation, both mother and child had a favourable outcome. Postoperative investigation of acute renal failure demonstrated a supra-adrenal mass. Further investigation confirmed bilateral phaeochromocytoma as the cause of her condition. A literature review confirmed this to be a rare but important clinical entity, owing to its high mortality. Antenatal diagnosis greatly improves survival. Magnesium sulphate appears to be a useful and safe agent to employ in cases of undiagnosed hypertensive obstetric emergencies.

Effect on Neonatal Outcome of Pharmacological Interventions for Attenuation of the Maternal Haemodynamic Response to Tracheal Intubation: A Systematic Review

The primary aim of this systematic review was to assess the effect on neonatal outcome of pharmacological interventions used for attenuation of the haemodynamic response to tracheal intubation in patients undergoing caesarean Section under general anaesthesia. A systematic search of randomised controlled trials from 1990 to 2015 was conducted. The primary outcome measure was the Apgar score at five minutes and secondary outcomes were umbilical arterial blood gas parameters and neurological adaptive capacity scores. Twenty-seven randomised controlled trials (1,689 patients) were included in the qualitative synthesis. Only five studies using opioids (383 patients) and five studies using non-opioid analgesics (358 patients) were subjected to meta-analysis. The Apgar score at five minutes was significantly lower in neonates of opioid-treated mothers (mean difference: −0.29, 95% confidence interval −0.56 to −0.02, P-value=0.03) compared to mothers in the control group; the umbilical arterial pH was lower and there was a higher requirement for tactile stimulation in neonates. No difference was seen in Apgar scores of neonates of mothers administered non-opioid analgesics compared to placebo. No difference was observed in other parameters between opioid- or non-opioid-treated mothers. This review suggests that opioid interventions for attenuation of the haemodynamic response to tracheal intubation in pregnant patients under general anaesthesia affect neonatal Apgar scores at five minutes in neonates but the difference did not appear to be clinically meaningful. We were unable to demonstrate any difference in safety.

Effect of Intravenous Magnesium Sulfate on the Minimum Alveolar Concentrations of Desflurane Using Bispectral Index Monitoring: A Prospective Randomized Double-blind Controlled Study

BACKGROUND

Magnesium sulfate has been implicated to influence the minimum alveolar concentration (MAC) of various volatile anesthetics, but its effect on desflurane remains unanswered so far.

AIM

To study the effect of perioperative intravenous magnesium sulfate on MAC of desflurane using bispectral index (BIS) monitoring.

SETTINGS

Operating room of a tertiary care hospital.

DESIGN

A prospective, randomized, controlled, double-blind clinical trial.

METHODS

Sixty American Society of Anesthesiologists Physical Status I/II patients aged 18-65 years and scheduled for breast conservative surgeries were randomized into three groups of 20 each. Control group (Group 1) was administered 100 ml normal saline (NS) as bolus followed by NS infusion. Magnesium (Mg) was administered as bolus of 40 mg/kg in 100 ml NS followed by NS infusion in Group 2 and as bolus of 40 mg/kg followed by infusion of 10 mg/kg/h of Mg in NS in Group 3. Anesthesia was induced with propofol, fentanyl, and atracurium. Dial setting of desflurane was adjusted to target a BIS of 45-55. Time from cessation of desflurane to beginning of spontaneous movement, time taken to respond to verbal commands, time of extubation, and time taken to reach BIS value of 70 were recorded.

STATISTICAL ANALYSIS

Statistics was done using SPSS program using ANOVA and the Chi-square test for variables and a P < 0.05 was taken to indicate a significant difference.

RESULTS

No significant difference was present in MAC, end-tidal desflurane, and cumulative consumption of morphine. Recovery was similar in Group 2 and Group 3, but time to eye opening (P = 0.011), time to respond to verbal commands (P < 0.001), and time to extubate (P < 0.001) were significantly delayed when compared with patients in Group 1. Hemodynamic changes were comparable among three groups.

CONCLUSIONS

From this study, we conclude that MACs of desflurane using BIS as a guide remains unaffected by perioperative infusion of magnesium sulfate.

The Influence of Two Different Doses of Magnesium Sulfate on Intraocular Pressure Variations after Injection of Succinylcholine and Endotracheal Intubation: A Prospective, Randomized, Parallel Three-Arm, Double-blind, Placebo-controlled Clinical Trial

Background:

The use of succinylcholine for rapid sequence induction in patients with open globe injuries may be detrimental to the eye.

Aim:

The aim of this study is to determine if the premedication with magnesium sulfate (MgSO₄) could attenuate the increase in intraocular pressure (IOP) associated with succinylcholine injection and intubation.

Setting:

Operation theaters in a tertiary care University Hospital between December 2014 and July 215.

Design:

This was a prospective, randomized, parallel three-arm, double-blind, placebo-controlled clinical trial.

Participants:

One hundred and thirteen patients’ physical status ASA Classes I and II underwent elective cataract surgery under general anesthesia.

Patients and Methods:

These patients allocated into three groups: Group C (control group) received 100 ml normal saline, Group M1 received 30 mg/kg MgSO₄ in 100 ml normal saline, and Group M2 received 50 mg/kg MgSO₄ in 100 ml normal saline. IOP, mean arterial pressure (MAP), and heart rate (HR) reported at 5-time points related to study drug administration. In addition, any adverse effects related to MgSO₄ were recorded. Intragroup and between-groups differences were examined by analysis of variance test.

Results:

We noticed a significant decrease in IOP in M1 (n = 38) and M2 (n = 37) groups as compared with C group (n = 38) after study drugs infusion, 2 and 5 min after intubation, P < 0.001. While the difference between M1 and M2 groups was insignificant, P = 0.296 and P = 0.647, respectively. There was a significant decrease in MAP and HR in M1 and M2 groups as compared with C group 2 and 5 min after intubation, P = 0.01. While the difference between M1 and M2 groups was insignificant, P = 1.

Conclusion:

MgSO₄ 30 mg/kg as well as 50 mg/kg effectively prevented the rise in IOP, MAP, and HR associated with rapid sequence induction by succinylcholine and endotracheal intubation.

Magnesium in obstetric anesthesia and intensive care

Magnesium, one of the essential elements in the human body, has numerous favorable effects that offer a variety of possibilities for its use in obstetric anesthesia and intensive care. Administered as a single intravenous bolus dose or a bolus followed by continuous infusion during surgery, magnesium attenuates stress response to endotracheal intubation, and reduces intraoperative anesthetic and postoperative analgesic requirements, while at the same time preserving favorable hemodynamics. Applied as part of an intrathecal or epidural anesthetic mixture, magnesium prolongs the duration of anesthesia and diminishes total postoperative analgesic consumption with no adverse maternal or neonatal effects. In obstetric intensive care, magnesium represents a first-choice medication in the treatment and prevention of eclamptic seizures. If used in recommended doses with close monitoring, magnesium is a safe and effective medication.

Pre-delivery remifentanil infusion for placenta accreta cesarean delivery under general anesthesia: an observational study

OBJECTIVE

General anesthesia may be required for placenta accreta cesarean delivery. Intrauterine fetal anesthetic exposure should be minimized to avoid neonatal respiratory depression; opioids are often delayed until post-delivery.

METHODS

In this observational study, we compared neonatal outcome using pre-delivery remifentanil versus post-delivery (deferred) opioids for placenta accreta cesarean delivery. Choice of anesthesia was discretionary. The primary outcome was Apgar score at 5 min comparing women who received pre-delivery remifentanil versus deferred opioid administration. We recorded maternal/obstetric characteristics, surgical characteristics, maternal hemodynamic data, neonatal outcomes: Apgar scores, umbilical vein pH and respiratory interventions at birth.

RESULTS

Between February 2007 and April 2014 we identified 40 general anesthesia placenta accreta cesarean deliveries. The remifentanil dose rate ranged from 0.06 to 0.46 mcg kg(-1 )min(-1). Obstetric and maternal characteristics were similar. Neonatal Apgar, umbilical pH and respiratory intervention outcomes were similar in both groups; Apgar scores median (interquartile range IQR [range]) at 5 min were 9 (8-10) for pre-delivery remifentanil versus 9 (9-10) for deferred opioid administration, p = 0.18.

CONCLUSIONS

We did not observe a significant effect on neonatal Apgar scores at 1 and 5 min, or respiratory interventions at birth when remifentanil infusion was administered pre-delivery.

Effect of peri-operative intravenous infusion of lignocaine on haemodynamic responses to intubation, extubation and post-operative analgesia

BACKGROUND AND AIMS

Lignocaine in intravenous (IV) bolus dose has been used for minimising haemodynamic changes associated with intubation and extubation. Furthermore, IV infusion has been used for post-operative analgesia. We investigated whether IV peri-operative lignocaine (bolus and infusion) would be able to produce both the effects simultaneously in elective laparoscopic cholecystectomies.

METHODS

In this randomised prospective study, 60 patients undergoing elective laparoscopic cholecystectomy were randomly divided into two groups of 30 each. In Group A, patients received 6 ml normal saline as bolus over 10 min followed by 6 ml/h infusion whereas in Group B, patients received preservative free 2% lignocaine 1.5 mg/kg IV bolus (made to a volume of 6 ml with normal saline) administered over a period of 10 min and thereafter an infusion at a rate of 1.5 mg/kg/h (pre-diluted in normal saline made to a volume of 6 ml/h. P < 0.05 was considered as significant.

RESULTS

The rise in pulse rate (PR) and mean arterial pressure (MAP) were less in Group B as compared to the Group A (P < 0.05) during intubation as well as during extubation. Furthermore, the Group B had significant longer mean pain-free post-operative period of 5½ h as compared to 54.43 min in the Group A (P < 0.05).

CONCLUSION

Administration of lignocaine infusion attenuates the rise in PR as well as MAP during the peri-intubation and peri-extubation period. Furthermore, infusion of lignocaine significantly increases the mean pain-free period post-operatively.

Anesthetic management of labor and delivery in patients with elevated intracranial pressure

The anesthetic management of labor and delivery in patients with elevated intracranial pressure is complex. This review discusses the etiologies of diffuse and focal pathologies which lead to elevated intracranial pressure in pregnancy. The role of neuraxial and general anesthesia in the management of labor and delivery is also examined. Finally, a comprehensive review of strategies to minimize increases in intracranial pressure during general anesthesia for cesarean delivery is presented.

Prevention of peri-induction hypertension in preeclamptic patients: a focused review

Many medications have been used to prevent the hypertensive response to the induction of general anesthesia and laryngoscopy in preeclamptic patients, with varying results. In this focused review, we summarize the available data and pharmacologic profiles of these drugs. Several different drug classes may be used safely; however, magnesium bolus, lidocaine, calcium channel antagonists other than nicardipine, and hydralazine are not recommended. Further research is warranted into the hemodynamic impact of varying the induction drug dose or combining different classes of drugs.

Anaesthetic management for emergency caesarean section in a patient with an untreated recently diagnosed phaeochromocytoma

Phaeochromocytoma is a rare cause of hypertension during pregnancy with potentially fatal consequences. If not detected and treated early in pregnancy, it is catastrophic for both the mother and the baby. Management requires close co-ordination between the obstetrician, anaesthesiologist, paediatrician and the endocrinologist. Perioperative management for an emergency caesarean section in a parturient with untreated phaeochromocytoma is an anaesthetic challenge and no standard recommendations have been reported till date. In this case report, we present anaesthetic management in such a case with successful maternal and foetal outcome.

Minimal effective dose of magnesium sulfate for attenuation of intubation response in hypertensive patients

STUDY OBJECTIVE

To study the minimal effective dose of magnesium sulfate to control blood pressure (BP) during intubation in hypertensive patients.

DESIGN

Prospective, randomized, double-blind study.

SETTING

Operating room of an academic medical center.

PATIENTS

80 adult, ASA physical status 1 and 2, controlled hypertensive patients undergoing elective surgery under general anesthesia and requiring endotracheal intubation.

INTERVENTIONS

Patients were randomized to 4 groups. Patients in study groups received a magnesium sulfate infusion at a dose of 30 (Group I), 40 (Group II), or 50 mg/kg (Group III) before induction of anesthesia, while patients in control group (Group IV) received a 1.5 mg/kg lidocaine bolus 90 seconds before intubation. Anesthesia was induced and maintained with a propofol infusion. Laryngoscopy and intubation were performed 4 minutes after administration of vecuronium.

MEASUREMENTS

Heart rate (HR) and BP were recorded before, during, and after endotracheal intubation for 10 minutes. Measures to manage hemodynamic instability were recorded. Serum magnesium levels were also recorded.

MAIN RESULTS

The changes in HR were comparable among groups. Mean arterial pressure (MAP) was maintained within normal limits in Group I patients while Groups II and III patients showed a significant decrease in MAP (P = 0.01) compared with baseline. A total of 6 patients (30%) in Group II and 10 patients (50%) in Group III required interventions (P = 0.001). No patient in Group I and only one patient (5%) in Group IV required intervention.

CONCLUSIONS

Magnesium 30 mg/kg is the optimum dose to control BP during intubation in hypertensive patients. A further increase in the dose of magnesium may cause significant hypotension.

[Anesthesia and preeclampsia]

An assessment of the patient must take place as early as possible in view of anaesthesia. It is recommended to perform a clotting screen as close as possible to the performing of an epidural anaesthesia. The use of aspirin, if indicated for the prevention of PE, does not as such, constitute a contraindication to performing an epidural anaesthesia if: With regards to the minimum platelet count, the recommended cut-off value for the performing of an epidural and spinal anaesthesia are 75 & 50 x 10(9)/l respectively, only if all of the following conditions are met: It is recommended to quickly set up an epidural anaesthesia because this will improve the blood pressure as well as the utero-placenteric haemodynamics and also because this will facilitate the management in case of a caesarean section. Whereas methylergometrine (Methergin) is contraindicated in the preeclamptic patient, it is possible to use oxytocin (Syntocinion) during and after labour. Before performing a spinal anaesthesia, it is recommended to restrain the administration of crystalloids to a maximum of 1000 ml. Also the i.v. antihypertensive treatment should be reduced or interrupted until complete establishment of the anaesthetic. In case a general anaesthesia is to be performed, an assessment of the criteria for difficult intubation should be performed immediately prior to the induction. The technique employed should be a rapid sequence induction with intubation, while preventing a surge in blood pressure induced by the tracheal intubation. Difficulties to extubate should systematically be anticipated. It is possible to perform a loco-regional anaesthesia following an eclamptic crisis if the following conditions are met: In case of overlapping seizures and/or impaired consciousness, a general anaesthesia is recommended.

Critical care management of severe pre-eclampsia

Severe pre-eclampsia is a common disorder in developing countries but still remains a significant problem in developed societies. The management of severe pre-eclampsia in developing countries is frequently hampered by lack of adequate facilities; paradoxically those countries with sufficient resources have a lower incidence of the disease and consequently lack experience in the treatment of severe pre-eclampsia. The management of these patients is further compromised because obstetricians generally lack the necessary knowledge and skills in critical care and conversely critical care specialists may lack appreciation and knowledge of pregnancy physiology and pathophysiology. Patients with severe pre-eclampsia therefore present an interdisciplinary challenge to obstetricians and physicians, who need to be familiar with pregnancy physiology and the current concepts in the pathogenesis and pathophysiology of severe pre-eclampsia. Patients who develop multisystem disease are most appropriately managed by an experienced obstetrician in an obstetric intensive care unit with a physician in consultation.

Répercussions maternelles et néonatales de l'anesthésie générale par rémifentanil pour césarienne programmée

OBJECTIVE

Opioids are routinely omitted at the induction of general anesthesia for Caesarean delivery because of the risks of respiratory neonatal depression. The short-acting opioid remifentanil may afford advantages at the induction and surgical stimulation, without subsequent neonatal depression.

PATIENTS AND METHODS

In this double-blinded study, 40 at term women undergoing elective Caesarean section and requiring general anaesthesia were allocated randomly to receive either remifentanil (0,5 microg/kg) at the induction of anaesthesia (G1, n=20) or placebo (G2, n=20). Induction of anaesthesia was performed with propofol 2 mg/kg and succinylcholine 1 mg/kg. Anaesthesia was maintained with nitrous oxide in oxygen (50/50%, v/v), propofol (100 microg/kg/min), remifentanil (0.2 microg/kg/min) and atracurium. Neonates were assessed by using Apgar scores, possible respiratory depression, with or without ventilation in the mask or intubation and umbilical cord blood gas (artery: UA and vein: UV). Values are expressed as mean values +/-SD. Pearson's Chi squared and t-test were used for statistical analysis P<0.05 was considered significant.

RESULTS

Maternal systolic pressure, mean pressure and heart rate were significantly higher in G1 at induction. Apgar scores, heart and respiratory rate were similar between groups. Seven episodes of respiratory depressions were noted (3 in G1, 4 in G2). Five neonates required only brief assisted ventilation by face-mask (2 in G1, 3 in G2).

CONCLUSION

Remifentanil (0.5 microg/kg) at the induction of anaesthesia in elective Caesarean section under general anaesthesia can be used without subsequent neonatal depression. However, we believe that further research is necessary to extrapolate these results to a pregnancy carrying an acutely distressed foetus.

Undiagnosed phaeochromocytoma mimicking severe preeclampsia in a pregnant woman at term

We report an unusual case of phaeochromocytoma in pregnancy. The patient presented with severe hypertension, visual disturbances, proteinuria, glycosuria and pulmonary oedema at 38 weeks' gestation. The initial diagnosis was severe preeclampsia, but rapid deterioration of the fetus necessitated an emergency caesarean section under general anaesthesia, following which the maternal condition deteriorated rapidly. Differential diagnoses included pulmonary embolus, cardiomyopathy, amniotic fluid embolus and ischaemic/embolic cerebrovascular accident. Despite aggressive maximal treatment, mother and baby died 36 h later. Post mortem examination of the mother revealed a 5.5-cm tumour of the right adrenal gland confirmed histologically as a phaeochromocytoma. We examine the diagnostic dilemmas of this case and consider the treatment and management options when faced with a critically ill mother and the need to deliver her fetus by emergency caesarean section. We also question the clinical priorities during management of a sudden deterioration in both maternal and fetal health.

The effects of magnesium sulphate on sevoflurane minimum alveolar concentrations and haemodynamic responses

BACKGROUND AND OBJECTIVE

Magnesium administered before anaesthesia induction results in a significant reduction in intravenous anaesthetic consumption. The purpose of this study was to evaluate whether the dose of intravenous magnesium sulphate reduces the minimum alveolar anaesthetic concentration of sevoflurane for endotracheal intubation (MACEI) and skin incision (MAC), and attenuates haemodynamic responses.

METHODS

We studied 60 patients who were scheduled for elective surgery. Patients were not premedicated before induction of anaesthesia and were randomly assigned to receive intravenous saline 0.9% (Group I, n = 20) or magnesium sulphate 30 mg kg(-1) bolus + 10 mg kg(-1) h(-1) continuous infusion (Group II, n = 20) or 50 mg kg(-1) bolus + 10 mg kg(-1) h(-1) continuous infusion (Group III, n = 20).

RESULTS

Median and 95% confidence limits for sevoflurane MACEI were 2.68 (2.48-2.85), 2.88 (2.70-3.06) and 2.96 (2.70-3.16), and for sevoflurane MAC were 2.08 (1.76-2.40), 2.26 (2.08-2.47) and 2.40 (2.19-2.68) in Groups I, II and III, respectively. The differences in MACEI and MAC among groups were not statistically significant, except Group III in MAC study (P < 0.05). Mean arterial pressures and heart rate did not increase in Groups II and III after endotracheal intubation and skin incision.

CONCLUSIONS

Magnesium sulphate administered before induction of anaesthesia increases MAC of sevoflurane and reduces cardiovascular responses to intubation.

The Comparative Effects of Remifentanil or Magnesium Sulfate Versus Placebo on Attenuating the Hemodynamic Responses After Electroconvulsive Therapy

In this prospective, randomized, double-blind, placebo-controlled, crossover study we compared the effects of remifentanil or magnesium sulfate (MgSO4) versus placebo in attenuating the sympathetic response to electroconvulsive therapy. Twenty adults underwent a total of 115 anesthetics for therapeutic electroconvulsive therapy. Patients were randomly allocated twice into each of the three test groups: placebo control, MgSO4 30 mg/kg, or remifentanil 1.0 microg/kg. Systolic and diastolic arterial blood pressures, heart rate, and oxygen saturations were recorded before IV access was established. Anesthesia was induced with thiopental 4 mg/kg. The trial drug was then administered and neuromuscular blockade was followed with succinylcholine 0.5 mg/kg before electroconvulsive therapy was performed. All measurements were repeated at 0, 1, 3 and 10 min after the seizure ended. Remifentanil and MgSO4 produced a statistically significant attenuation of the increase in systolic arterial blood pressure at 0, 1, and 3 min (P < 0.05). Remifentanil, but not MgSO4 or placebo, attenuated the increase in heart rate at 1 and 3 min but not the peak rate. Remifentanil increased the duration of apnea (mean 90 s), with no other adverse respiratory effects. Mean seizure duration time was 33 (+/- 14) s, with no difference among the groups. In conclusion, remifentanil 1.0 microg/kg and MgSO4 30 mg/kg attenuated the systolic arterial blood pressure response to electroconvulsive therapy without reducing the duration of seizure activity. Because MgSO4 has less effect on HR, it might offer advantages over remifentanil in patients at risk for post-electroconvulsive therapy bradycardia.

General anaesthesia with target controlled infusion of propofol for planned caesarean section: maternal and neonatal effects of a remifentanil-based technique

The present case series evaluated maternal and neonatal effects of remifentanil, combined with propofol, during general anaesthesia for caesarean delivery. Following written informed consent, ten patients scheduled for semi-elective caesarean section were recruited to this prospective, unblinded trial. All patients with non-reassuring fetal status were excluded. A 0.50-micrograms/kg bolus of remifentanil was given intravenously, followed by a continuous infusion of 0.20 micrograms.kg(-1)min(-1). Anaesthesia was induced using propofol target controlled infusion set at a blood concentration of 5 micrograms/mL, 45 s after the remifentanil bolus. Following tracheal intubation the propofol target was reduced to 2.5 micrograms/mL and remifentanil maintained at 0.20 micrograms.kg(-1)min(-1). Mean arterial pressure remained stable throughout anaesthesia. Two patients experienced episodes of hypotension (mean arterial pressure decrease >20%). Although neonatal depression occurred in six babies and assisted mask ventilation was required briefly, recovery was rapid without the need for naloxone or tracheal intubation. Umbilical artery pH was >7.20 in all infants. We conclude that the results of the present case series using a remifentanil/propofol-based technique of general anaesthesia for caesarean section provide a basis to study the safety of this technique in a larger population. Under the conditions of the present trial, this anaesthetic technique seems safe for mother and infant, provided adequate precautions are taken to manage brief, self-limiting infant respiratory depression. At the moment we cannot advise the routine use of this technique, especially since it has not been studied in situations of fetal compromise.

In patients with head injury undergoing rapid sequence intubation, does pretreatment with intravenous lignocaine/lidocaine lead to an improved neurological outcome? A review of the literature

It is well known that laryngeal instrumentation and endotracheal intubation is associated with a marked, transient rise in intracranial pressure (ICP). Patients with head injury requiring endotracheal intubation are considered particularly at risk from this transient rise in ICP as it reduces cerebral perfusion and thus may increase secondary brain injury. The favoured method for securing a definitive airway in this patient group is by rapid sequence intubation (RSI). In the United States the Emergency Airway Course teaches emergency physicians to routinely administer intravenous lidocaine as a pre treatment for RSI in this patient group in an attempt to attenuate this rise in ICP. A literature search was carried out to identify studies in which intravenous lidocaine was used as a pretreatment for RSI in major head injury. Any link to an improved neurological outcome was also sought. Papers identified were appraised in the manner recommended by the evidence based medicine group to ensure validity. There were no studies identified that answered our question directly and, furthermore, it is our belief that no such study, at present, exists in the literature. Six valid papers were found, which individually contained elements of the question posed and these are presented in a narrative and graphic form. There is currently no evidence to support the use of intravenous lidocaine as a pretreatment for RSI in patients with head injury and its use should only occur in clinical trials.

Phaeochromocytoma: an unusual cause of hypertension in pregnancy

A primiparous, full-term, 28-year-old woman underwent an emergency lower segment Caesarean section under epidural anaesthesia for failure to progress in the first stage. Despite an uneventful pregnancy and delivery, she developed a hypertensive crisis in the postoperative period complicated by acute pulmonary oedema requiring ventilation for 48 h in the intensive care unit. Intravenous magnesium sulphate infusions and hydralazine boluses were used to control the blood pressure, which was associated with clonus, hyperreflexia, tachycardia and profuse sweating. The patient made a good recovery. Later measurement of urinary catecholamines in the recovery phase showed greatly elevated levels of norepinephrine, dopamine and vanillyl mandelic acid. Further investigations included a normal abdominal computed tomography scan and a I-123 meta-iodo-benzyl-guanidine scintigraphy scan which revealed a 3- to 4-cm irregular tumour located at the level of the lower pole of the right kidney and further liver hot spots. Intravenous magnesium sulphate infusion proved successful in controlling hypertension caused by a phaeochromocytoma in the postpartum period.

Alfentanil given immediately before the induction of anesthesia for elective cesarean delivery

Opioids are routinely omitted at the induction of general anesthesia for cesarean delivery because of concerns about neonatal respiratory depression. The subsequent unmodified maternal stress response to tracheal intubation reduces placental perfusion. The short-acting opioid alfentanil may afford advantages at the induction, without subsequent neonatal depression. In this double-blinded study of elective cesarean deliveries, 40 patients were allocated randomly to receive either alfentanil 10 microg/kg (n = 18) or placebo (n = 22), 1 min before the induction of anesthesia with thiopental 4 mg/kg and succinylcholine 1.5 mg/kg. Anesthesia was maintained with 50% nitrous oxide, 0.5% isoflurane in oxygen, and atracurium. Neonates were assessed by using Apgar scores, Neurologic and Adaptive Capacity Scores, and umbilical cord blood gas and catecholamine analysis. After intubation, mothers receiving alfentanil had a smaller increase in mean arterial blood pressure, (11 +/- 15 vs 31 +/- 13 mm Hg, P < 0.001) and lower plasma norepinephrine concentrations, (336 +/- 152 vs 486 +/- 241 pg/mL, P < 0.05). Neonates in the alfentanil group had greater umbilical arterial oxygen tensions (27.8 +/- 7.0 vs 22.6 +/- 7.4 mm Hg), slightly reduced Apgar scores (both P < 0.05), but similar Neurologic and Adaptive Capacity Scores. One neonate in the alfentanil group required naloxone. The maternal stress response was attenuated in the alfentanil group but at the cost of early neonatal depression. However, all neonates should be monitored for possible immediate, but transient, respiratory depression.

Remifentanil in emergency caesarean section in pre-eclampsia complicated by thrombocytopenia and abnormal liver function

We describe the use of remifentanil in a woman with severe pre-eclampsia who presented for emergency caesarean section. Remifentanil was effective in obtunding the hypertensive response to laryngoscopy and intubation. Previous studies have found no significant adverse effects of remifentanil on the neonate. With its short duration of action, the use of this new opioid has several potential advantages in the above setting. Further studies are required to explore the use of remifentanil as an adjunct to obstetric general anaesthesia.

Anaesthesia for caesarean section in a patient with recent subarachnoid haemorrhage and severe pre-eclampsia

Subarachnoid haemorrhage is a leading 'indirect' cause of maternal death in the UK. We describe the case of a 43-year-old woman who presented with headache, photophobia and neck stiffness of sudden onset at 32 weeks' gestation. Cerebral computed tomography demonstrated subarachnoid blood in the cisterns around the midbrain, and oral nimodipine was started to prevent vasospasm. Preparations were made for endovascular coil embolisation in the event of identification of a posterior circulation aneurysm. However, angiography under general anaesthesia failed to reveal any vascular abnormality. On emergence from anaesthesia, headache persisted, and over the next 24 h severe pre-eclampsia developed. Magnesium sulphate was started, and urgent Caesarean section performed under general anaesthesia without incident. The rationale for the neuroradiological, obstetric and anaesthetic management is discussed.

General anesthesia with remifentanil for Cesarean section in a parturient with an acoustic neuroma

PURPOSE

To describe the anesthetic management of a parturient with a large acoustic neuroma undergoing general anesthesia with remifentanil for Cesarean section.

CLINICAL FEATURES

A near-term parturient presented with a large intracranial mass. Cesarean section under general anesthesia was elected one week prior to craniotomy for tumour resection. Remifentanil infusion, 0.2-1.0 microg x kg(-1) x min(-1), was used from induction to emergence of general anesthesia. The neonate was born seven minutes after the remifentanil infusion was started. She had normal umbilical cord pH and her Apgar scores were 7 and 8, at one and five minutes respectively. Although the neonate received supplemental oxygen, she did not require naloxone. Both mother and neonate made an uneventful recovery.

CONCLUSION

Remifentanil was effective in producing stable hemodynamic conditions, without severe neonatal respiratory depression, during induction and maintenance of general anesthesia for a Cesarean delivery in a parturient with a large intracranial tumour.

Management of pre-eclampsia and haemolysis, elevated liver enzymes, and low platelets syndrome

Pre-eclampsia remains a major cause of maternal and fetal ill-health. Defective placentation and endothelial dysfunction appear to underlie the clinical features. Recent publications regarding the diagnosis, treatment, prediction and prevention of pre-eclampsia, and contemporary issues in the management of the haemolysis, elevated liver enzymes, and low platelets syndrome, are discussed in this review.

Spinal haematoma following epidural anaesthesia in a patient with eclampsia

A patient with a twin pregnancy required a Caesarean section for severe pre-eclampsia. Her platelet count was 71 x 10(9).l-1. Epidural anaesthesia was performed after platelet transfusion. A spinal epidural haematoma was diagnosed postoperatively. A generalised tonic-clonic seizure sparing the lower limbs enabled early diagnosis to be made. The patient recovered with no permanent neurological damage after laminectomy and clot removal. The risks and benefits of regional techniques require careful consideration, and postoperative monitoring for recovery of neural blockade is essential.

Mivacurium for caesarean section in hypertensive parturients receiving magnesium sulphate therapy

The interaction between mivacurium and magnesium sulphate was investigated in a group of parturients undergoing caesarean section under general anaesthesia. Thirty parturients were studied; 10 normotensive controls (group NT), 10 hypertensive controls (group HT) and 10 hypertensives who received magnesium sulphate (group HTM). At induction group HT received 30 microg/kg of alfentanil and group HTM 10 microg/kg of alfentanil and 30 or 60 mg/kg of magnesium sulphate. Neuromuscular function was monitored by electromyography. Mivacurium 0.15 mg/kg was given after 60% recovery of T1 following succinylcholine. Magnesium concentrations and plasma cholinesterase activity were significantly elevated in group HTM (1.57 +/- 0.53 mmol/1 and 4.60 +/- 1.27 kU/1) compared with group HT (0.71 +/- 0.18 mmol/1 and 3.44 +/- 0.97 kU/1) and group NT (0.60 +/- 0.07 mmol/1 and 2.86 +/- 0.82 kU/1) (P < 0.005). Time to maximal recovery, and time from 25-75% of maximal recovery from mivacurium, were significantly prolonged in group HTM (60.9 +/- 15.3 min and 16.8 +/- 5.6 min) compared with group HT (34.9 +/- 7.6 min and 7.6 +/- 3.6 min) and group NT (37.4 +/- 14.4 min and 8.5 +/- 3.4 min) (P < 0.01). Time to 25% recovery was prolonged in group HTM (35.1 +/- 7.4 min) compared with the other two groups (HT: 21.6 +/- 6.4 min and NT: 22.8 +/- 10.2 min) (P < 0.01). Whilst the duration of action of mivacurium, determined by electromyography, is prolonged by subtherapeutic serum magnesium concentrations, of the available non-depolarizing relaxants mivacurium would seem to be most appropriate for caesarean section.