Epidural block does not worsen oxygenation during one-lung ventilation for lung resections under isoflurane/nitrous oxide anaesthesia.

BACKGROUND AND OBJECTIVES: The aim of this prospective, randomized, controlled clinical study was to evaluate the effects of thoracic epidural anaesthesia combined with isoflurane/nitrous oxide anaesthesia on intraoperative oxygenation during one-lung ventilation for lung resections. METHODS: Forty patients were randomly allocated to receive general anaesthesia maintained with isoflurane/nitrous oxide (group General, n = 20) or the same anaesthetic combined with thoracic epidural anaesthesia (group Integrated, n = 20). All patients were mechanically ventilated with the same settings (FiO2 = 0.5; VT = 9 mL kg(-1); inspiratory: expiratory time = 1:1; inspiratory pause = 10%). Effects on oxygenation were evaluated by determining the changes in PaO2/FiO2 ratio at 10, 30, 45 and 60 min of one-lung ventilation as compared to values obtained after induction of anaesthesia (supine, two-lung ventilation). RESULTS: The PaO2/FiO2 ratio was decreased in both groups during one-lung ventilation until the end of surgery. No differences were found at any observation time between the groups. Ventilation with 100% oxygen because of SpO2 decrease <92% was required in nine patients of group General (45%) and in eight patients of group Integrated (40%) (P = 0.64). Manual re-inflation of the operated lung was required in one patient of group General only (P = 0.99). Heart rate was lower in group Integrated than in group General throughout the study. No differences between the two groups in mean arterial pressure were observed. CONCLUSIONS: Adding a thoracic epidural block to isoflurane/nitrous oxide anaesthesia during one-lung ventilation for lung resections does not result in clinically relevant detrimental effects on intraoperative oxygenation.

Prospective, randomized, controlled evaluation of the preventive effects of positive end-expiratory pressure on patient oxygenation during one-lung ventilation.

BACKGROUND AND OBJECTIVE: This prospective, randomized, controlled study evaluated the effects on oxygenation by applying a selective and patient-specific value of positive end-expiratory pressure (PEEP) to the dependent lung during one-lung ventilation. METHODS: Fifty patients undergoing thoracic surgery under combined epidural/general anaesthesia were randomly allocated to receive zero PEEP (Group ZEEP, n = 22), or the preventive application of PEEP, optimized on the best thoracopulmonary compliance (Group PEEP, n = 28). Patients' lungs were mechanically ventilated with the same setting during two- and one-lung ventilation (FiO2 = 0.5; VT = 9mL kg(-1), inspiratory :expiratory time = 1 : 1, inspiratory pause = 10%). RESULTS: Lung-chest wall compliance decreased in both groups during one-lung ventilation, but patients of Group PEEP had 10% higher values than patients with no end-expiratory pressure (ZEEP) applied--Group ZEEP (P < 0.05). During closed chest one-lung ventilation, the PaO2 : FiO2 ratio was lower in Group PEEP (232 +/- 88) than in Group ZEEP (339 +/- 97) (P < 0.05); but no further differences were reported throughout the study. No differences were reported between the two groups in the need for 100% oxygen ventilation (10 patients of Group ZEEP (45%) and 14 patients of Group PEEP (50%) (P = 0.78)) or re-inflation of the operated lung during surgery (two patients of Group ZEEP (9%) and three patients of Group PEEP (10%) (P = 0.78)). Postanaesthesia care unit discharge required 48 min (25th-75th percentiles: 32-58 min) in Group PEEP and 45 min (30-57 min) in Group ZEEP (P = 0.60). CONCLUSIONS: The selective application of PEEP to the dependent, non-operated lung increases the lung-chest wall compliance during one-lung ventilation, but does not improve patient oxygenation.

Cervical plexus anesthesia for carotid endarterectomy: comparison of ropivacaine and mepivacaine.

PURPOSE: To evaluate the effectiveness of cervical plexus block performed with ropivacaine 0.75% or 1%, or mepivacaine 2%. METHODS: In a prospective, randomized, double-blind study, 60 patients received deep cervical plexus block with 0.2 ml x kg(-1) divided among C2-C4 injections using ropivacaine 0.75% and 1% or mepivacaine 2%. A blinded observer recorded loss of pin-prick sensation every minute in the C2-C4 dermatomes until readiness for surgery. Then, a superficial cervical block was performed with 0.15 ml x kg(-1) lidocaine 1%. The need for intraoperative supplemental analgesia and degree of pain and time of first postoperative pain medication were also recorded. RESULTS: General anesthesia was not required to complete surgery in any case. No differences in the need for intraoperative supplemental analgesia was observed (7, 6, and 9 patients with ropivacaine 0.75% and 1% or mepivacaine 2%, respectively). Readiness to surgery required 15 (10-25) min with ropivacaine 0.75%, 18 (8-20) min with ropivacaine 1%, and 15 (5-20) min with mepivacaine 2% (P = NS); while patients asked for first postoperative pain medication after 10 (4-13) hr and 9 (6.5 - 11) hr with ropivacaine 0.75% and 1% compared with 5 (0-8) hr with mepivacaine 2% (P<0.05). CONCLUSION: Ropivacaine 0.75% or 1% are appropriate choices when performing cervical plexus anesthesia for carotid endarterectomy, providing nerve block characteristics similar to those of mepivacaine 2%, but with the advantage of longer postoperative pain relief.

Unexpected cardiac arrest during epidural anaesthesia.

We reported the case of sudden asystole requiring close chest cardiac massage in a 56-yrs-old health man receiving epidural anaesthesia for elective transurethral resection of bladder tumour (TURBT). The anaesthetic procedure was performed in a regional-block-room. Cardiac arrest developed few minutes after local anaesthetic injection, before the patient has been transferred to the operating room. The importance of patient monitoring during regional anaesthesia must be further on pointed out, especially when the anaesthetic procedure is performed out of the operating room (e.g. in the recovery room or in a "regional-block-room").