Persistent cortical blindness after a thoracic epidural test dose of bupivacaine.

Thoracic epidural anesthesia is considered as an essential component of the perioperative care for patients undergoing lung resection. Although neurologic adverse events have been associated with this technique, permanent injury is rare. These events primarily involve the peripheral nervous system; for example, nerve root injury. We present a case of persistent cortical blindness after a test dose of bupivacaine was administered into an uneventfully placed thoracic epidural catheter.

Spinal anesthesia for intrapartum Cesarean delivery following epidural labor analgesia: a retrospective cohort study.

PURPOSE: Failed conversion of epidural labor analgesia (ELA) to epidural surgical anesthesia (ESA) for intrapartum Cesarean delivery (CD) has been observed in clinical practice. However, spinal anesthesia (SA) in parturients experiencing failed conversion of ELA to ESA has been associated with an increased incidence of serious side effects. In this retrospective cohort analysis, we examined our routine clinical practice of removing the in situ epidural, rather than attempting to convert to ESA, prior to administering SA for intrapartum CD. METHODS: Hemodynamic data, frequencies of either high or total spinal block, and maternal and neonatal outcome data were gathered from the anesthesia records of all parturients at the Amphia Hospital, undergoing intrapartum CD between January 1, 2001 and May 1, 2005. RESULTS: Complete data were available for 693 patients (97.6%) of the 710 medical records that were identified. Of the 693 patients, 508 (73.3%) had no ELA and received SA, 128 patients (18.5%) received SA following epidural anesthesia for labor, 19 (2.7%) underwent conversion of ELA to ESA, and 38 (5.5%) received general anesthesia. When comparing both SA groups, no clinically relevant differences were observed regarding the incidence of total spinal block (0% in both groups) or high spinal block (0.2 vs 0.8%, P = 0.36). The number of hypotensive episodes, the total amount of ephedrine administered, and the Apgar scores recorded at 5 and 10 min were similar amongst groups. CONCLUSIONS: The incidence of serious side effects associated with SA for intrapartum CD following ELA is low and not different compared to SA only.

Factors affecting the distribution of neural blockade by local anesthetics in epidural anesthesia and a comparison of lumbar versus thoracic epidural anesthesia.

The spread of sensory blockade after epidural injection of a specific dose of local anesthetic (LA) differs considerably among individuals, and the factors affecting this distribution remain the subject of debate. Based on the results of recent investigations regarding the distribution of epidural neural blockade, specifically for thoracic epidural anesthesia, we noted that the total mass of LA appears to be the most important factor in determining the extent of sensory, sympathetic, and motor neural blockade, whereas the site of epidural needle/catheter placement governs the pattern of distribution of blockade relative to the injection site. Age may be positively correlated with the spread of sensory blockade, and the evidence is somewhat stronger for thoracic than for lumbar epidural anesthesia. Other patient characteristics and technical details, such as patient position, and mode and speed of injection, exert only a small effect on the distribution of sensory blockade, or their effects are equivocal. However, combinations of several patient and technical factors may aid in predicting LA dose requirements. Based on these results, we have also formulated suggested epidural insertion sites that may optimize both analgesia and sympathicolysis for various surgical indications.

Continuous positive airway pressure breathing increases cranial spread of sensory blockade after cervicothoracic epidural injection of lidocaine.

BACKGROUND: Continuous positive airway pressure (CPAP) increases the caudad spread of sensory blockade after low-thoracic epidural injection of lidocaine. We hypothesized that CPAP would increase cephalad spread of blockade after cervicothoracic epidural injection. METHODS: Twenty patients with an epidural catheter at the C6-7 or C7-T1 interspace received an epidural dose of lidocaine while breathing at ambient pressure (control group), or while breathing with 7.5 cm H2O CPAP. After injection, we evaluated the spread of sensory blockade. Spirometry variables before and after epidural injection were also measured. RESULTS: Data are presented as median (interquartile range) values. Sensory block ranged from C7 (C4-7) to T4 (T4-6) in the control group and from C2 (C2-4) to T4 (T2-5) in the CPAP group (P = 0.003 for the cranial border). The total number of segments blocked was 7.5 (6.8-9.8) in the control group and 10 (8-12) in the CPAP group (P = 0.13). The number of segments blocked cranial to the injection site was one (0.8-3.5) in the control group and five (3.5-7) in the CPAP group (P = 0.006). The number of patients with a maximal cranial block (up to C2) was one in the control group and seven in the CPAP group (P = 0.02). In both groups, there was a small but significant decrease from baseline in spirometry values, with no differences between groups. CONCLUSION: Applying CPAP during cervicothoracic epidural injection of lidocaine resulted in a more cranial extension of sensory blockade when compared with breathing at ambient pressure.

Continuous positive airway pressure breathing increases the spread of sensory blockade after low-thoracic epidural injection of lidocaine.

Factors affecting the distribution of sensory blockade after epidural injection of local anesthetics remain incompletely clarified. To evaluate if increasing intrathoracic pressure affects the spread of thoracic epidural anesthesia, we randomized 20 patients who received an epidural catheter at the T7-8 or T8-9 intervertebral space into 2 groups. The control group (n = 10) received an epidural test dose of 4 mL lidocaine 2% during spontaneous breathing at ambient pressure. The continuous positive airway pressure (n = 10) group received the same epidural test dose but during spontaneous respiration with 7.5 cm H2O continuous positive airway pressure. The groups were comparable with respect to demographic variables. Fifteen minutes after the conclusion of the epidural injection, the sensory block ranged from from T4 [median, interquartile range 2.75 segments] to T11 (interquartile range 3.5 segments) in the control group and from T5 (interquartile range 2.25 segments) to L2 (IQR 2.25 segments) in the continuous positive airway pressure group (P = 0.005 for the caudal border). The total number of segments blocked was 7 (median, interquartile range 2.25) in the control group and 11 (interquartile range 3.5) in the continuous positive airway pressure group (P = 0.004). The number of segments blocked caudad to the injection site was 3 (median, interquartile range 3.5) in the control group and 6 (interquartile range 2.25) in the continuous positive airway pressure group (P = 0.005). We conclude that continuous positive airway pressure increases the spread of sensory blockade in thoracic epidural anesthesia, primarily by a more caudad extension of sensory blockade.

A comparison of epidural pressures and incidence of true subatmospheric epidural pressure between the mid-thoracic and low-thoracic epidural space.

BACKGROUND: Differences in epidural pressure (EP) may influence the spread of blockade in thoracic epidural anesthesia. We evaluated if EP and the incidence of subatmospheric EP differ between the mid- and low-thoracic epidural space. METHODS: Patients received an epidural catheter at the T3-5 (MID group, n = 20) or T7-10 (LOW group, n = 20) intervertebral space, respectively. The epidural space was identified using a Tuohy needle connected to a pressure transducer, after which EP was measured. RESULTS: The epidural space could not be identified in three patients who were excluded from the study. EP data are presented as median value (interquartile range). Median EP was 1 mm Hg (-1 to 4.5) in the MID group, and 4 mm Hg (2-7.8) in the LOW group (P = 0.04). The incidence of an EP