Obstetrical analgesia in a parturient with antithrombin III deficiency

Antithrombin III (AT III) deficiency is a rare inherited disorder which predisposes patients to thrombotic complications. Anti-coagulation is necessary to prevent recurrent thrombosis and high doses of heparin are often required. Anticoagulation complicates analgesia in parturients with the condition. We describe such a patient, in pre-term labour, who was successfully managed during labour with intravenous nalbuphine and inhaled nitrous oxide (N₂O) La déficience en antithrombine est une maladie héréditaire rare qui prédispose aux complications thrombogénes. L’anticoagulation est nécessaire pour la prévention des thromboses récidivantes et requiert des doses élevées d’héparine. L’anticoagulation complique évidemment l’anesthésie de la parturiente. Nous rapportons un cas d’une patiente en travail avant terme, dont l’accouchement s’est déroulé sans complications sous nalbuphine et protoxyde d’azote.     

Obstetrical analgesia and anaesthesia in multiple sclerosis

OBJECTIVES: The use of epidural analgesia and anaesthesia is controversial in patients with multiple sclerosis (MS) due to the potential neurotoxicity of local anaesthetics. The aim of this study was to evaluate the place and the safety of epidural obstetrical analgesia in these patients. PATIENTS AND METHODS: A consecutive series of 19 patients with MS was studied over 4 years, recording the type of anaesthesia and the obstetric and neurologic observations during the pregnancy and post-partum. RESULTS: Ten patients had epidural analgesia. One patient had a caesarean section under epidural anaesthesia. Five patients relapsed during the post-partum period. Only one of them had an epidural for a spontaneous vaginal delivery, without any evidence of a causal relationship. Spinal anaesthesia is generally not advocated in the presence of MS due to concerns relating to the stronger local anaesthetics required and was therefore not used. CONCLUSION: The results confirm that epidural analgesia is innocuous in this context. The important points are the precise evaluation of the existing neurological symptoms and the sparing of local anaesthetics thanks to the addition of opioids.     

Obstetrical anaesthesia and analgesia in chronic spinal cord-injured women

Improved acuteand rehabilitativecareand emphasis on integrating patients into society after spinal cord injury is likely to result in increasing numbers of cord-injured women presenting for obstetrical care. Anaesthetists providing care to these women should be familiar with the complications resulting from chronic cord injury and aware that many may be aggravated by the physiological changes of normal pregnancy. These complications include reduced respiratory volumes and reserve, decreased blood pressure and an increased incidence of thromboembolic phenomena, anaemia and recurrent urinary tract infections. Patients with cord lesions above the T₅ spinal level are at risk for the life-threatening complication of autonomic hyperreflexia (AH) which results from the loss of central regulation of the sympathetic nervous system below the level of the lesion. Sympathetic hyperactivity and hypertension result in response to noxious stimuli entering the cord below the level of the lesion. Labour appears to be a particularly noxious stimulus and patients with injuries above T₅ are at risk for AH during labour even if they have not had previous AH episodes. Morbidity is related to the degree of hypertension and intracranial haemorrhage has been reported during labour and attributed to AH. We report our experience in providing care to three parturients with spinal cord injuries. Two patients had high cervical lesions, one of whom experienced AH during labour and was treated with an epidural block. The second was at risk for AH having had episodes in the past and received an epidural block to provide prophylaxis for AH. In both cases epidural blockade provided effective treatment and prophylaxis for AH. The third patient had alow thoracic cord lesion, a comfortable labour but required an urgent Caesarean section performed under general anaesthesia for placental abruption and antepartum haemorrhage. The outcome of all three maternal-neonatal pairs was excellent. We recommend antepartum anaesthesia consultation for all cordinjured mothers and an epidural block as prophylaxis against AH in all parturients with cord lesions at T₅ or above.     

Epidural analgesia in a pregnant woman with essential thrombocythaemia

Epidural analgesia is often considered as risk of epidural haematoma in patient with essential thrombocythaemia because of the platelet disorder. In this observation, uncomplicated epidural analgesia was performed in a pregnant woman with asymptomatic essential thrombocythaemia, because the absence of bleeding symptoms was associated with normal thrombo-elastography and time of occlusion by PFA-100 suggesting normal platelet function. PFA-100 is a biological test evaluating platelet function in whole blood, which is easy and quick to perform. This case study suggests that this test might be useful in evaluating platelet function in obstetrics but must be validated before recommending its extensive use.     

Labour epidural analgesia for a woman with hereditary macrothrombocytopenia

Epidural analgesia is often considered as risk of epidural haematoma in a patient with thrombocytopenia. In this observation, uncomplicated epidural analgesia was performed in a pregnant woman with hereditary macrothrombocytopenia. She received continuous epidural labour analgesia for a vaginal delivery with a platelet count at 63x10(9)/l but platelets with high mean platelet volume (20fL) and normal function. No neurological sequelae or excessive bleeding occurred.     

Epidural analgesia in labor for a woman with an intrathecal baclofen pump

A 28-year-old woman in active labor at 38 weeks of gestation requested epidural analgesia. She had previously received an intrathecal baclofen infusion pump to relieve the spasticity of cerebral palsy. She had right hemiparesis and cerebral palsy but was otherwise healthy. The patient had been seen one month before her expected delivery date by a staff anesthesiologist. A lumbar X-ray demonstrated the intrathecal catheter entering the L3-4 interspace and extending to the mid-thoracic region. For labor analgesia the epidural space was identified at L4-5 with the patient sitting, using a standard 17-gauge Tuohy needle. An epidural catheter was threaded to 5 cm and provided effective analgesia until delivery four hours later. There were no postnatal complications.     

Labor epidural analgesia for a woman with a pityriasis versicolor in the lumbar region

Epidural analgesia is usually contraindicated in case of infection at the site of needle insertion. Tinea versicolor is a benign superficial cutaneous fungal infection caused by the proliferation of a skin commensal yeast of low pathogenicity. We report the case of a pregnant woman with a tinea versicolor in the lumbar region, who benefited from a labor epidural analgesia, realised with reinforced antiseptic measures. No neurological or infectious complication occurred.     

Postoperative nitrous oxide analgesia

Nitrous oxide is occasionally used as an analgesic agent in the postoperative period. The feasibility of administering a known concentration from an air entrainment oxygen mask, using a primary flow of Entonox, (50% oxygen/50% nitrous oxide) was investigated. Accurox (C.R. Bard Canada Inc.) blenders, disconnected from their facemasks, were studied using a primary flow of Entonox. An increase in air entrainment of approximately 13% was demonstrated. Concentrations of about 20% nitrous oxide in oxygen enriched air, appropriate for postoperative analgesia, can be produced, but the methods are extravagant in the use of Entonox and are likely to be slightly unreliable.     

Tolerance to nitrous oxide analgesia in rats and mice.

The purpose of these experiments was to characterize the nature of tolerance to the analgesic action of nitrous oxide. Analgesia was assessed in rats using a tail-flick latency test and in mice using an abdominal constriction test. Rats and mice were exposed to nitrous oxide, 75 per cent, the balance oxygen, continuously for 16--18 hours. On re-exposure to nitrous oxide 30 min later, these animals were found tolerant to nitrous oxide in that the analgesic response was decreased by at least 50 per cent. Animals tolerant to nitrous oxide were not tolerant to morphine. Morphine (0.25--1.5 mg/kg) produced equal degrees of analgesia in control and nitrous oxide-tolerant mice and rats. In contrast, rats made tolerant to morphine by repeated daily injections of as much as 400 mg/kg subcutaneously or by subcutaneous implantation of morphine pellets (75 mg, twice) showed a decreased analgesic response to nitrous oxide. Thus the cross-tolerance between nitrous oxide and morphine appears unique in that it is unidirectional.     

Nitrous oxide analgesia in selected dental patients

Nitrous oxide analgesia is presented as the analgesic method of choice in medically compromised patients. The resemblance between the action of nitrous oxide and that of morphine is emphasized. The combination of the opiate-like action of nitrous oxide with the advantages of an inhalation technique makes it preferable and superior to parenteral opiate administration. It may thus be termed as an inhalation “opiate”.Since its introduction into clinical use by Wells in 1844 (1), nitrous oxide (N₂0) has been applied as an anesthetic and analgesic agent in various medical situations, including dentistry (2). The development of equipment affording safe administration of accurate concentrations of either pre-mixed or adjustable N₂0 and oxygen enabled the application of “relative analgesia” as an important technique in the relief of pain. The pharmacological action and analgesic properties of N₂0 received renewed interest after Berkowitz et al (3) showed the resemblance between its mode of action and that of opiates. Recent human and animal studies indicated that N₂0 activates the endogenous opiate system(s) in a manner similar to that of morphine (4). The availability of an analgesic gas which, on the one hand, mimics opiate action whilst on the other hand its administration is continuously adjustable, as opposed to other modes of sedation, makes it into an ideal adjunct in dental procedures. Owing to its minimal side effects, the use of N₂0 is especially recommended in the management of anxious children and medically compromised patients.This report presents three illustrative patients in whom nitrous oxide proved to be the drug of choice during dental procedures.