The effect of intravenous ondansetron on maternal haemodynamics during elective caesarean delivery under spinal anaesthesia: a double-blind, randomised, placebo-controlled trial.

BACKGROUND: Spinal anaesthesia for caesarean delivery is frequently associated with adverse effects such as maternal hypotension and bradycardia. Prophylactic administration of ondansetron has been reported to provide a protective effect. We studied the effect of different doses of ondansetron in obstetric patients. METHODS: This prospective double-blind, randomised, placebo-controlled study included 128 healthy pregnant women scheduled for elective caesarean delivery under spinal anaesthesia. Women were randomly allocated into four groups (n=32) to receive either placebo or ondansetron 2, 4 or 8 mg intravenously before induction of spinal anaesthesia. Demographic, obstetric, intraoperative timing and anaesthetic variables were assessed at 16 time points. Anaesthetic variables assessed included blood pressure, heart rate, oxygen saturation, nausea, vomiting, electrocardiographic changes, skin flushing, discomfort or pruritus and vasopressor requirements. RESULTS: There were no differences in the number of patients with hypotension in the placebo (43.8%) and ondansetron 2mg (53.1%), 4 mg (56.3%) and 8 mg (53.1%) groups (P=0.77), nor the percentage of time points with systolic hypotension (7.3% in the placebo group and 11.1%, 15.7% and 12.6% in the ondansetron 2, 4 and 8 mg groups, respectively, P=0.32). There were no differences between groups in ephedrine (P=0.11) or phenylephrine (P=0.89) requirements and the number of patients with adverse effects. CONCLUSIONS: In our study, prophylactic ondansetron had little effect on the incidence of hypotension in healthy parturients undergoing spinal anaesthesia with bupivacaine and fentanyl for elective caesarean delivery.

[An update of the obstetrics hemorrhage treatment protocol]. / Actualización del protocolo de tratamiento de la hemorragia obstétrica.

Obstetric hemorrhage is still a major cause of maternal and fetal morbimortality in developed countries. This is an underestimated problem, which usually appears unpredictably. A high proportion of the morbidity of obstetric hemorrhage is considered to be preventable if adequately managed. The major international clinical guidelines recommend producing consensus management protocols, adapted to local characteristics and keep them updated in the light of experience and new scientific publications. We present a protocol updated, according to the latest recommendations, and our own experience, in order to be used as a basis for those anesthesiologists who wish to use and adapt it locally to their daily work. This last aspect is very important to be effective, and is a task to be performed at each center, according to the availability of resources, personnel and architectural features.

[Analgesic techniques for labour: alternatives in case of epidural failure]. / Técnicas analgésicas para el parto: alternativas en caso de fallo de la epidural.

Epidural analgesia is now the method of choice for the treatment of pain in labour and delivery. However, this technique may fail and provide inadequate or null alleviation to the mother. This paper reviews the risk factors, possible causes and possible therapeutic alternatives to inadequate analgesia, whether pharmacological therapies (neuroaxial, peripheral blocks or analgesic administration via intravenous or inhalational routes) or non-pharmacological ones (relaxation techniques, psychological or mechanical). In all possible cases the efficacy and indications of alternative therapies based on the published literature are reviewed, especially from the point of view of evidence-based medicine. The need is underscored of a multifactorial therapeutic approach to the pregnant woman, not just restricting ourselves to eliminating the pain of childbirth.

[Clinical and pharmacological study of the efficacy of carbetocin in elective caesareans compared to low and usual doses of oxytocin]. / Estudio clínico y farmacoeconómico de la eficacia de la carbetocina en cesáreas electivas respecto a la oxitocina a dosis bajas y a dosis habituales.

OBJECTIVES: To evaluate uterine contractility, bleeding, haemodynamic performance, and side effects of different doses of oxytocin after delivery under spinal anaesthesia in caesarean section without prior labour in childbirth. We also perform a pharmacoeconomic evaluation. MATERIAL AND METHODS: A randomised, descriptive, observational and multicentre prospective study was conducted, which included 104 ASA 1 patients divided into 3 groups. Group 1 (n=52) received after removal of the foetus and coinciding with foetal umbilical cord clamping, 1 IU of oxytocin followed by an infusion of 2.5 UI×h(-1); Group 2 (n=52) a continuous infusion of 20IU oxytocin at a rate of 700mUI×min(-1) followed later by 10UI×h(-1), and group 3, 100µg bolus dose of carbetocin only. RESULTS: There were no statistical differences between groups in anthropometric, obstetric or anaesthetic variables. Significant differences in uterine contraction in vaginal bleeding and the incidence of side effects, particularly headache and tremor, were more pronounced in the carbetocin group. CONCLUSIONS: With these results, we cannot recommend the routine use of carbetocin in caesarean sections, because it is accompanied by an increased incidence of side effects without any improvement in the prevention of obstetric haemorrhage. Finally, it is economically more expensive than the use of low doses of oxytocin, which may be the trend that should be considered in the future, due to the clinical outcomes, and its lower cost.

[Efficacy of low-dose oxytocin during elective cesarean section]. / Eficacia de la oxitocina a dosis bajas en cesáreas electivas.

BACKGROUND AND OBJECTIVE: In cesarean section, the optimal dose of oxytocin to reduce the risk of hemorrhage with the least risk of adverse effects has yet to be defined. We studied the effects of using 2 different doses of oxytocin in women undergoing elective cesarean section under spinal anesthesia. The women had had no prior labor. MATERIAL AND METHODS: Randomized multicenter trial enrolling 104 patients classified as ASA 1. Following fetal extraction and coinciding with umbilical cord clamping, a group of 52 women received 1 IU of oxytocin followed by an infusion of 2.5 IU x h(-1); a second group of 52 women received a continuous infusion of 20 IU at a rate of 700 mlU x min(-1) followed by 10 IU x min(-1). We compared uterine contractility (assessed as absent, moderate, satisfactory), postoperative vaginal bleeding (absent, light, moderate, heavy), hemodynamics, and adverse effects after administration of oxytocin and fetal extraction (electrocardiographic abnormalities, nausea, vomiting, discomfort, headache, blushing, trembling, chills, or chest pain). RESULTS: No significant between-group differences in patient, obstetric, or anesthetic variables were detected. Uterine contraction was satisfactory in over 90% of the patients in both groups on initial assessment during surgery. After surgery, vaginal bleeding was absent or light in over 90% of the women. No significant differences in adverse events were detected between groups. CONCLUSIONS: The incidence of obstetric bleeding is not higher when a lower dose of oxytocin is used; the rate of postoperative adverse events also does not increase.

Allergy to low dose sugammadex.

We describe the case of a fit 17-year-old man who developed a severe allergic reaction to a low clinical dose of sugammadex (3.2 mg kg(-1) , 200 mg intravenously), 1 min after its administration. This was manifest by an intense erythema over the anterior part of the thorax, severe lip and palpebral oedema and bilateral wheeze. On later investigation, the patient had a positive skin prick test to sugammadex (5-mm diameter response, with a negative saline control and positive histamine control of 5 mm) and no response to any other drug tested. Other diagnostic tests supported a diagnosis of allergic reaction to sugammadex.

[Phase II blockade after a subclinical dose of succinylcholine: importance of neuromuscular monitoring]. / Bloqueo fase II después de una dosis subclínica de succinilcolina. Importancia de la monitorización neuromuscular.

Neuromuscular monitoring is not a routine practice in clinical settings worldwide. The little interest expressed is mainly because clinicians lack information and documentation, even though the literature on the subject is vast and experts agree that routine monitoring reduces morbidity related to the use of neuromuscular blockers. We report a case of an unusual phase II neuromuscular block from a subclinical dose of succinylcholine. The blockade lasted longer than expected in a patient with diminished plasma cholinesterase activity. We emphasize that monitoring neuromuscular function aided diagnosis and observation of the block during emergency surgery.

[Neuromuscular blockade monitoring. Part 1]. / Monitorización del bloqueo neuromuscular. 1a parte.

Many recent studies have underlined the importance of quantitative neuromuscular monitoring and the high incidence of residual block in clinical practice in spite of the use of nondepolarizing neuromuscular blockers of intermediate duration. Neuromuscular monitoring facilitates the tailoring of the muscular paralysis and appropriate patient recovery at the end of surgery. Monitoring also controls or prevents residual block and serves to guide the use of reversing agents. This review describes the physiology of neuromuscular junctions as well as the principles and patterns of nerve stimulation and clinical monitoring. In addition to drawing on their own experience, the authors have reviewed the literature available through evidence-based indexes and other databases up to December 2008. Most references found were case series and reviews. Quantitative monitoring is an evidence-based practice that should be applied in all situations in which a neuromuscular block is established.

[Effects of changes in ion concentrations, osmolarity, and pH on recovery from atracurium- or vecuronium-induced neuromuscular blockade]. / Efecto de las variaciones iónicas, la osmolaridad y el pH sobre la recuperación del bloqueo neuromuscular no despolarizante por atracurio y vecuronio.

OBJECTIVES: To determine changes in sodium, potassium, calcium, magnesium and chloride ion concentrations in blood, osmolarity, and pH during surgery, and to assess the influence of such changes on atracurium- or vecuronium-induced neuromuscular blockade under inhaled or intravenous anesthesia. MATERIAL AND METHODS: Prospective study randomizing 119 ASA 1-2 patients; 52.1% of the patients received atracurium (26.8%, with isoflurane; 25.2%, with propofol) and 47.9% received vecuronium (23.5%, with isoflurane; 24.3%, with propofol). The neuromuscular blockade was confirmed by electromyography of the adductor pollicis muscle (stimuli delivered to the cubital nerve). Two venous blood samples were extracted to measure ureic nitrogen, creatinine, glucose, ion concentrations (sodium, chloride, potassium, calcium, and magnesium), and osmolarity. Arterial blood gases and pH were also assessed. The first blood sample was extracted on inserting the venous catheter and the second on recovery of 25% of the first train-of-four twitch. RESULTS: The onset and duration of action for equipotent doses of atracurium and vecuronium were similar. Likewise, recovery was also similar. Plasma chloride ion and glucose levels tended to rise during surgery, while sodium, potassium and magnesium ion concentrations fell. Both total and effective plasma osmolarities also decreased. Fluid replacement therapy during surgery was at least partly responsible for these changes. Low calcium and magnesium concentrations and alkalosis prolonged some phases of atracurium recovery, while low sodium levels shortened the duration of some atracurium-induced blockade recovery phases. The effect of changes in chloride ion concentrations on recovery was variable. High chloride, low calcium, and especially low sodium ion concentrations shortened some phases of the vecuronium-induced blockade, while alkalosis prolonged its duration. CONCLUSIONS: Changes in electrolyte concentrations and pH as a result of standard fluid replacement therapy are moderate, well tolerated, and do not exercise a strong effect on the behavior of the neuromuscular blockade.

[Eclampsia and total bilateral amaurosis in a woman subsequently diagnosed with reversible posterior leukoencephalopathy syndrome]. / Eclampsia y amaurosis total bilateral en una paciente con diagnóstico a posteriori de leucoencefalopatía posterior reversible.

Eclampsia is a complication of preeclampsia and is characterized by the appearance of grand mal seizures and/or coma, in the absence of any other neurological abnormalities. Neither focal neurological deficit nor prolonged coma tends to develop following a crisis. Eclampsia should therefore lead us to consider other clinical entities that may require special treatment. We report the case of a pregnant woman who presented total bilateral loss of vision following a grand mal seizure. The patient was subsequently diagnosed with reversible posterior leukoencephalopathy syndrome, which has clinical and radiologic manifestations linked to several causes, such as hypertensive encephalopathy, eclampsia, kidney failure, and immunosuppressant therapy. The syndrome involves headache, altered states of consciousness, changes in vision (including blindness), and seizures; these symptoms generally coincide with a rapid increase in blood pressure. Diagnosis requires neuroimaging, and the typical finding is edema in the posterior zones of the brain hemispheres. The most widely accepted hypothesis concerning the pathophysiologic mechanism underlying this syndrome is failure of cerebral autoregulation with development of vasogenic edema. The prognosis is good and the alterations usually resolve completely with appropriate treatment, which is the same as for the management of eclampsia, with strict monitoring of blood pressure.

[Air embolism during elective cesarean section, and uterine atony due to fetal macrosomia]. / Embolia aérea durante cesáirea electiva y atonía uterina por feto macrosómico.

We report the case of a paradoxical air embolism during a scheduled cesarean section for fetal macrosomia (7.010 kg) in a 38-year-old woman with a history of gestational diabetes and preeclampsia. Spinal anesthesia was satisfactory and well tolerated. After approximately 30 minutes (coinciding with uterine exteriorization), the patient presented a sudden episode of dyspnea, confusion, hypotension, and ST segment depression. The episode lasted approximately 10 minutes and resolved spontaneously with no sequelae. Neurological status and the electrocardiogram were normal at the end of surgery and no postoperative lesions were observed. In the immediate postoperative period, the patient presented a massive hemorrhage due to uterine atony. Echocardiography revealed a patent foramen ovale. The clinical signs in this patient are highly suggestive of a paradoxical cerebral and coronary air embolism.