This prospective investigation was conducted to evaluate the efficacy of different volumes of epidural blood patch (EBP) for treatment of postdural puncture headache (PDPH) in 81 consecutive patients. In the first part of the investigation (Study part I), 10 ml of blood was injected for EBP in 28 patients. In the second randomized part of the investigation (Study part II), the patients were allocated to receive for EBP either 10 ml (27 patients) or 10-15 ml (26 patients), according to the height of the patient. The procedure was considered initially successful if PDPH disappeared completely during the 2-h recovery room follow-up. To evaluate the long-term success, a questionnaire was mailed to all patients. The EBP performed 3.7 +/- 2.9 days following the dural puncture was initially successful in 88-96% of the patients in the different study groups. In the questionnaire, only 50-68% of the patients reported that PDPH had disappeared immediately without recurrence. In 16-36% of the patients the PDPH returned at lesser intensity and in 14-17% PDPH was reported to have continued, disappearing gradually in all patients. Despite this, 87% of all patients were satisfied with the EBP treatment. There were no statistically significant differences between the groups. The results indicate that a larger, height-adjusted volume of blood for EBP in adults does not produce a better effect on PDPH compared to a standard 10-ml volume. Despite the excellent initial effect (91%) seen in our patients, a permanent effect of the blood patch was only achieved in 61%.

Spinal anaesthesia was compared in 40 obese patients (increased body mass index (BMI] and 40 patients with normal BMI when 3 ml of plain 0.5% bupivacaine was injected at either the L3-4 or L4-5 interspace. More extensive cephalad spread of sensory block was achieved in patients with increased BMI compared with patients with normal BMI after injection at both L3-4 and L4-5 (P less than 0.05). The use of the L3-4 interspace instead of L4-5 resulted in a higher mean spread of block in patients with both increased (T4 vs T8) or normal (T9 vs T11) BMI (P less than 0.05). The interindividual variability of the blocks was relatively small in patients with normal BMI injected at L4-5, compared with the three other groups (normal BMI injected at L3-4, increased BMI injected at L3-4 and L4-5). Good anaesthesia was produced in all patients for orthopaedic surgery of the lower extremity. In an obese patient it is recommended that plain bupivacaine be administered at L4-5 instead of L3-4 when extensive spread of the block is to be avoided.

Interscalene block may cause phrenic nerve block and decreased diaphragmatic motion. We evaluated the effect of continuous interscalene block on ventilatory function and diaphragmatic motion. We studied ten patients scheduled for surgery or manipulation of the shoulder. Preoperatively, the patients underwent spirometry and double-exposure chest radiography. They received an interscalene block with 0.75% bupivacaine. Thereafter, 0.25% bupivacaine was infused into the interscalene space for 24 h. Spirometry was repeated three times and double-exposure radiography twice. The maximal inspiratory and expiratory pressures were measured repeatedly. Haemoglobin oxygen saturation (SPO2) was monitored with pulse oximetry. The block provided adequate anaesthesia for surgery or manipulation. All patients had a marked ipsilateral paresis of the diaphragm in the radiographs 3 h after the initial block. Twenty-one hours later five patients had diaphragmatic motility comparable to the situation before the block. In the other five patients, the amplitude of diaphragmatic motility on the side of the block was only 4-37% of the values before the block. All patients had a clear reduction in forced vital capacity (FVC), forced expiratory volume in 1s (FEV1) and peak expiratory flow (PEF) 3 and 8 h after the block without signs of dyspnoea. In conclusion, in all our patients interscalene block caused an ipsilateral hemidiaphragm paresis, which in five of ten patients persisted until the end of the continuous block.

Possible correlations between age and certain characteristics of spinal blockade with plain bupivacaine were investigated in 124 patients, ages ranging from 15 to 92 yr. Three millilitre of 0.5% solution (sp. gr. 1.000 at 37 degrees C) was injected at the L3-L4 interspace. There were great individual variations in all age groups, but the maximum spread of analgesia increased with age, although the correlation was poor (P less than 0.05). The spread of analgesia to L2 and L3 segments in the oldest patients (greater than or equal to 70 yr) was about twice as fast as that in the youngest (less than 30 yr). Complete motor blockade of the lower extremities developed most rapidly in the oldest patients (greater than or equal to 80 yr; mean 11 min), while in patients younger than 50 yr the mean time to complete motor block was approximately doubled. The mean sensory recovery of the two uppermost segments and the mean sensory recovery of the S1 segment did not correlate significantly with age. The decrease of systolic arterial pressure was correlated with the height of the sensory block only in the oldest (greater than or equal to 80 yr) patients. Post-spinal headache was encountered in two patients (1.6%).