Identification of epidural space using air with normal saline
Notice bibliographique
Résumé
Identification of the epidural space has been achieved by a number of techniques, of which loss of resistance to air or saline is the most commonly used. Some anaesthetists prefer air while others advocate using normal saline [1]. Whereas no serious adverse effects have been associated with the use of saline, there are a number of case reports describing complications associated with the use of air for identification of the epidural space [2]. The list of complications includes venous air embolism, pneumocephalus and patchy distribution of epidural block [2]. Despite this, a large number of anaesthetists including ourselves have been continuing to use air for identifying the epidural space. A recent survey showed that more than 30% of obstetric anaesthetists in Britain preferred air to normal saline [3]. The superior quality of the ‘feel’ that one gets throughout the insertion of the Tuohy needle is the reason why we prefer using air. Recently, we devised a new approach using both air and normal saline together. We use a combination of three-way taps connected together between the Tuohy needle and the loss of resistance syringe ( Fig. 9). The side ports of these three-way taps are connected using a short length of extension tubing forming a vertical loop. The three-way taps are then turned so that they communicate with each other through the extension tubing connected to their side ports. Arrangement of three-way taps and tubing attached to Tuohy needle and loss of resistance syringe. Note that for the purpose of illustration an opaque liquid has been used in place of saline. Normal saline is drawn up through the Tuohy needle connected to this assembly. Thus, the dead space of the needle and the descending limb of the loop formed by the extension tubing contain normal saline. The syringe and the ascending limb, on the other hand, contain only air. The three-way taps are locked, the tip of the Tuohy needle inserted into the lumbar intervertebral space selected and at a depth of 2 cm the three-way taps are unlocked. The needle is advanced feeling the resistance to the column of air in the syringe and the ascending limb of the loop. On entering the epidural space, however, it is the normal saline from the descending limb of the loop that is injected first and not the air. Using this technique, we experience the same quality of resistance that is usually felt using air. An extension tubing with two male ends can be used to connect the three-way taps. We constructed our own as shown in the figure. The dead space of the descending limb should be 2–4 ml as this is the volume that tends to get injected at loss of resistance. The whole assembly must be tested for leaks before beginning the procedure.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».