Background. The safety of epidural anaesthesia in patients at risk for right ventricular
pressure overload remains controversial. We compared the haemodynamic effects of vascular
and cardiac autonomic nerve block, induced by selective lumbar (LEA) and high thoracic epidural
anaesthesia (TEA), respectively, in an animal model subjected to controlled acute right
ventricular pressure overload.
Methods. Eighteen pigs were instrumented with epidural catheters at the thoracic (T) and
lumbar (L) level and received separate injections at T2 (1 ml) and L3 (4 ml) with saline (s) or
bupivacaine 0.5% (b). Three groups of six animals were studied: (i) a control group (LsþTs), (ii)
LEA group (LbþTs), and (iii) TEA group (LsþTb). Haemodynamic measurements including
biventricular pressure-volumetry were performed. Right ventricular afterload was then
increased by inflating a pulmonary artery (PA) balloon. Measurements were repeated after
30 min of sustained right ventricular afterload increase.
Results. LEA decreased systemic vascular resistance (SVR) and did not affect ventricular function.
TEA had minor effects on SVR but decreased left ventricular contractility while baseline
right ventricular function was not affected. Control and LEA-treated animals responded similarly
to a PA balloon occlusion with an increase in right ventricular contractility and heart rate.
Animals pretreated with a TEA did not show this positive inotropic response and developed
low cardiac output in the presence of right ventricular pressure overload.
Conclusions. In contrast to LEA, TEA reduced the haemodynamic tolerance to PA balloon
occlusion by inhibiting the right ventricular positive inotropic response to acute pressure overload

Objective: The aim of this study was to identify predictors
of delayed endotracheal extubation defined as the need for
postoperative ventilatory support after open thoracotomy
for lung resection.
Design: An observational cohort investigation.
Setting: A tertiary referral center.
Participants: The study population consisted of 2,068 patients
who had open thoracotomy for pneumonectomy, lobectomy,
or segmental lung resection between January
1996 and December 2005.
Interventions: Not applicable.
Measurements and Main Results: Preoperative and intraoperative
variables were collected concurrently with the patient’s
care. Risk factors were identified using logistic regression
with stepwise variable selection procedure on 1,000
bootstrap resamples, and a bagging algorithm was used to
summarize the results. Intraoperative red blood cell transfusion,
higher preoperative serum creatinine level, absence of a
thoracic epidural catheter, more extensive surgical resection,
and lower preoperative FEV1 were associated with an increased
risk of delayed extubation after lung resection.
Conclusion: Most predictors of delayed postoperative extubation
(ie, red blood cell transfusion, higher preoperative serum
creatinine, lower preoperative FEV1, and more extensive
lung resection) are difficult to modify in the perioperative period
and probably represent greater severity of underlying lung
disease and more advanced comorbid conditions. However,
thoracic epidural anesthesia and analgesia is a modifiable factor
that was associated with reduced odds for postoperative
ventilatory support. Thus, the use of epidural analgesia may
reduce the need for post-thoracotomy mechanical ventilation

Various techniques and drug regimes for thoracic paravertebral block (PVB) have been evaluated for post-thoracotomy analgesia, but there is no consensus on which technique or drug regime is best. We have systematically reviewed the efficacy and safety of different techniques for PVB. Our primary aim was to determine whether local anaesthetic (LA) dose influences the quality of analgesia from PVB. Secondary aims were to determine whether choice of LA agent, continuous infusion, adjuvants, pre-emptive PVB, or addition of patient-controlled opioids improve analgesia. Indirect comparisons between treatment arms of different trials were made using metaregression. Twenty-five trials suitable for metaregression were identified, with a total of 763 patients. The use of higher doses of bupivacaine (890–990 mg per 24 h compared with 325–472.5 mg per 24 h) was found to predict lower pain scores at all time points up to 48 h after operation (P=0.006 at 8 h, P=0.001 at 24 h, and P<0.001 at 48 h). The effect-size estimates amount to around a 50% decrease in postoperative pain scores. Higher dose bupivacaine PVB was also predictive of faster recovery of pulmonary function by 72 h (effect-size estimate 20.1% more improvement in FEV1, 95% CI 2.08%–38.07%, P=0.029). Continuous infusions of LA predicted lower pain scores compared with intermittent boluses (P=0.04 at 8 h, P=0.003 at 24 h, and P<0.001 at 48 h). The use of adjuvant clonidine or fentanyl, pre-emptive PVB, and the addition of patient-controlled opioids to PVB did not improve analgesia. Further well-designed trials of different PVB dosage and drug regimes are needed.

Review Article

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.

Authors: Al-Rawi, Omar Y. FRCA *; Pennefather, Stephen H. MRCP, FRCA *; Page, Richard D. FRCS +; Dave, Ishani FRCA *; Russell, Glen N. FRCA *

Institution From the Departments of *Anaesthesia and +Thoracic Surgery, Cardiothoracic Centre, Liverpool, United Kingdom.

Title The Effect of Thoracic Epidural Bupivacaine and an Intravenous Adrenaline Infusion on Gastric Tube Blood Flow During Esophagectomy.[Report]

Source Anesthesia & Analgesia. 106(3):884-887, March 2008.

Abstract BACKGROUND: Gastric tube necrosis is a major cause of anastomotic leak after esophagectomy. A correlation has been shown between reduced flux at the anastomotic end of the gastric tube and anastomotic leaks.

METHODS: We prospectively studied the effect of intraoperative thoracic epidural bupivacaine and subsequent adrenaline infusion on hemodynamics and flux in the gastric tube.

RESULTS: Administering the epidural bolus significantly decreased flux at the anastomotic end of the gastric tube (P < 0.01). Gastric flux was returned to baseline by an adrenaline infusion.

CONCLUSIONS: The administration of a thoracic epidural bolus may decrease flux at the anastomotic end of the gastric tube.

Background: The oesophagectomy procedure includes the formation of a gastric tube to re-establish the continuity of the gastrointestinal tract. The effect of thoracic epidural analgesia (TEA) on gastric mucosal blood flow (GMBF) remains unknown in clinical practice. The aim of this prospective observational study was to assess the microcirculatory changes induced by TEA in the early post-operative course.

Methods: Eighteen consecutive patients who underwent radical oesophagectomy with en-bloc resection and two-field lymphadenectomy for oesophageal cancer, and benefited from TEA during the post-operative course, were studied prospectively, and compared with nine patients who declined the use of TEA in the same period (control group). GMBF was measured using a laser Doppler flowmeter in three consecutive time periods (before and after 1 and 18 h of TEA infusion). Post-operative monitoring also included the measurement of arterial pressure, cardiac output, gas exchange and intrathoracic blood volume index.

Results: After the first and 18th hour of infusion, TEA induced an increase in GMBF compared with baseline and the control group. The mean arterial pressure and intrathoracic blood volume index decreased after the first hour of TEA infusion with no influence on the cardiac index.

Conclusions: This clinical study demonstrates that TEA improves the microcirculation of the gastric tube in the early post-oesophagectomy period. The clinical relevance of TEA in this setting should be validated in larger studies focusing on the clinical outcome following oesophagectomy.

Authors: Solak, O.; Metin, M.; Esme, H.; Solak, O.; Yaman, M.; Pekcolaklar, A.; Gurses, A.; Kavuncu, V.
Eur J Cardio-Thorac Surg 32: 9-12, 2007
Keywords: Chronic post-thoracotomy pain; Neuropathic pain; Gabapentin; Wound pain
Abstract (English): Background: Chronic post-thoracotomy pain (CPTP) consists of different types of pain. Some characteristics of CPTP are the same as those of recognized neuropathic pain syndromes. Objective: We aimed to determine the safety and efficacy of gabapentin (GP) in comparison to naproxen sodium (NS) in patients with CPTP. Methods: Forty consecutive patients with CPTP after posterolateral/lateral thoracotomy were prospectively evaluated. Twenty patients were given GP and another 20 were given NS treatment. Visual Analogue Scale (VAS) and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scorings were performed pretreatment (day 0) and on the 15th, 30th, 45th and 60th days. Adverse events were questioned. The mean ages were 45.7+/-14.9 and 49.8+/-15.2 years and the mean durations of pain were 3.8+/-0.9 and 3.8+/-1.1 months, respectively. Results: The mean pretreatment VAS scores (VAS0) were 6.4+/-0.6 and 6.8+/-0.6, the mean pretreatment LANSS scores (LANSS0) were 18.85+/-1.6 and 20.75+/-2.6 in GP and NS groups, respectively (p>0.05). Minor adverse events which did not mandate discontinuation of treatment were observed in seven patients (35%) in the GP and in four patients (20%) in the NS group. The number of patients with a VAS score <5 at the latest follow-up (VAS60<5) was 17 (85%) and 3 (15%) in GP and NS groups, respectively (p<0.001). Seventeen patients (85%) in the GP and 0 patients (0%) in the NS group had a LANSS score <12 at the latest follow-up. Conclusion: Gabapentin is safe and effective in the treatment of CPTP with minimal side effects and a high patient compliance. These results should be supported with multidisciplinary studies with larger sample sizes and longer follow-ups.

Objectives: This study was designed to evaluate the effectiveness of low-volume interscalene brachial plexus block for post-thoracotomy ipsilateral shoulder pain and to compare it with nonsteroidal anti-inflammatory drug treatment. Design: Prospective nonblinded study. Setting: University hospital. Participants: Sixty adult patients. Intervention: Patients who underwent elective thoracic surgery under combined epidural and general anesthesia, and after surgery were free of incisional pain but complaining of shoulder pain, were included in the study. They were selected in a sequential manner and placed into 2 groups of 30 patients each. Group 1 had a low-volume interscalene brachial plexus block, using 10 mL of bupivacaine 0.5%. Group 2 had an intramuscular injection of diclofenac sodium, 75 mg. Measurements and Main Results: Pain was measured during their stay in the postanesthesia care unit (PACU) by using a visual analog score (VAS). Opioids were administered when pain relief was incomplete. Pain intensity was re-estimated the next morning and patient satisfaction was scored. VAS was found to be significantly lower in the low-volume interscalene block group than in the diclofenac group at 30 minutes after treatment and when leaving PACU (p < 0.001 for both). Patients in the interscalene block group stayed longer in the PACU (p = 0.019), and significantly fewer required rescue opioids (p = 0.03). There was no significant difference between the groups in patient satisfaction with the pain treatment. Conclusions: The authors concluded that low-volume interscalene brachial plexus block is a superior treatment for post-thoracotomy shoulder pain compared with diclofenac injection, although it requires a slightly longer stay in the PACU. J Cardiothorac Vasc Anesth 21: 554-7, 2007

R. G. Davies1, P. S. Myles1,2,3,* and J. M. Graham4
1Department of Anaesthesia and Pain Management, Alfred Hospital Commercial Road, Melbourne, Victoria 3004, Australia
2Academic Board of Anaesthesia and Perioperative Medicine, Monash University Victoria 3800, Australia
3Centre for Clinical Research Excellence Canberra, Australia
4Department of Anaesthesia, Austin Hospital Heidelberg, Australia

*Corresponding author: Department of Anaesthesia and Pain Management, The Alfred Hospital, PO Box 315, Melbourne, VIC, 3004, Australia. E-mail: p.myles@alfred.org.au

Epidural analgesia is considered by many to be the best method of pain relief after major surgery. It is used routinely in many thoracic surgery centres. Although effective, side-effects include hypotension, urinary retention, incomplete (or failed) block, and, in rare cases, paraplegia. Paravertebral block (PVB) is an alternative technique that may offer comparable analgesic effectiveness and a better side-effect profile. We undertook a systematic review and meta-analysis of all relevant randomized trials comparing PVB with epidural analgesia in thoracic surgery. Data were abstracted and verified by both authors. Studies were tested for heterogeneity, and meta-analyses were done with random effects or fixed effects models. Weighted mean difference (WMD) was used for numerical outcomes and odds ratio (OR) for dichotomous outcomes, both with 95% CI.

We identified 10 trials that had enrolled 520 thoracic surgery patients. All of the trials were small (n<130) and none were blinded. There was no significant difference between PVB and epidural groups for pain scores at 4–8, 24 or 48 h, WMD 0.37 (95% CI: –0.5, 121), 0.05 (–0.6, 0.7), –0.04 (–0.4, 0.3), respectively. Pulmonary complications occurred less often with PVB, OR 0.36 (0.14, 0.92). Urinary retention, OR 0.23 (0.10, 0.51), nausea and vomiting, OR 0.47 (0.24, 0.53), and hypotension, OR 0.23 (0.11, 0.48), were less common with PVB. Rates of failed block were lower in the PVB group, OR 0.28 (0.2, 0.6). PVB and epidural analgesia provide comparable pain relief after thoracic surgery, but PVB has a better side-effect profile and is associated with a reduction in pulmonary complications. PVB can be recommended for major thoracic surgery.