The preliminary results were presented during the XVI International Congress of the Polish Society of Anaesthesiology and Intensive Therapy in Cracow in 2008.

Symptomatic cholecystolithiasis is a common disease, which in the majority of cases requires surgery. Despite the use of relatively low-invasive laparoscopic techniques, in some cases classic laparotomy from the right subcostal access (right oblique-transverse incision, so-called Kocher`s incision) is necessary. Such procedures are commonly performed both in emergency cases (e.g. acute cholecystitis) and elective surgeries. The classic method is also used in patients who require biliary decompression and temporary drainage. The recognized standard of anaesthesia for such procedures is general anaesthesia with intraoperative analgesia with intravenous opioids. Such a standard of management is applied in almost all centres in Poland. Regional anaesthesia in such cases is of limited use and is not routinely performed; it concerns mainly patients with indications for reduced doses or avoidance of opioids during anaesthesia.

In the Beskid Oncology Centre, thoracic paravertebral blocks (TPVB) have been used for several years. This technically simple anaesthesia may be extremely useful for breast surgery [1, 2]. The aim of the study was to assess the usefulness of unilateral paravertebral block before cholecystectomy, its effects on the course of anaesthesia, quality of intra- and postoperative analgesia, incidence of complications, postoperative nausea/vomiting and satisfaction of patients.

METHODS

The prospective, randomized study approved by the Bioethical Committee of the Beskid Medical Board in Bielsko-Biala was carried out amongst patients scheduled for classic cholecystectomy from the right subcostal access (Kocher`s incision). The inclusion criteria were: age above 18 years, no serious co-existing diseases (ASA I or II degree), and patients` written informed consent. The exclusion criteria involved body weight < 50 kg and > 95 kg, contraindications for block, pregnancy, and lack of consent.

Patients were randomly allocated to two groups. In control group, the procedure was performed under general anaesthesia whereas in study, the induction of anaesthesia was preceded by right-sided thoracic paravertebral block. In study group paravertebral anaesthesia was the basic form of intraoperative analgesia.

The procedure preparations were identical in both groups and involved: the anaesthetic visit on the day preceding surgery, oral premedication with midazolam in the dose of 7.5-15 mg, and subcutaneous enoxaparin, 40 mg 12 h before surgery in patients with higher risk of thromboembolic complications.

In both groups, general anaesthesia was induced with etomidate 0.2 mg kg-1 and rocuronium 0.6 mg kg-1. During the procedure, artificial lung ventilation was carried out using the mixture of oxygen and air with the flow of 3-6 L min-1 and sevoflurane in the concentration ensuring proper depth of anaesthesia. In control group, analgesia was provided with fentanyl in fractionated doses.

In study group, prior to surgery, thoracic paravertebral block by the classic Eason and Wyatt method was applied [3]. Under infiltration anaesthesia with 1% solution of lidocaine, a subarachnoid 22G needle was inserted at the level of Th8, about 2.5-3 cm to the right from the midline and the paravertebral space was identified using the loss-of-resistance method. Having confirmed the proper position of the needle using the hanging-drop method, the mixture of 0.5% ropivacaine with fentanyl 0.1mg and clonidine 75 µg was administered to the paravertebral space. The standard volume of the solution was 0,3 mL kg-1: 20 mL in patients with lower body weight and maximum volume – 25 mL in obese patients. In cases of difficulties in identifying the paravertebral space at the planned level, the block was performed one or two levels above Th8. Once local anaesthesia symptoms were achieved within the Th6-Th10 dermatomes (the extent involving the Kocher`s incision and roots of the greater visceral nerve), general anaesthesia was induced.

The postoperative pain management involved intramuscular or intravenous methamizole; if insufficient, ketoprofen or/and tramadol were used; doses of all analgesics administered were recorded.

In both groups, the basic demographic data of patients were compared. The anaesthesia was assessed recording MAP, SpO2 and HR at 5, 10, 15, 30, 45 and 60 min of the procedure and after its completion. All anaesthesia-related complications were recorded; mean consumption of agents used during anaesthesia and duration of procedures were noted. The severity of postoperative pain was measured at 1, 6, 24, 48, and 72 h using the Numerical Pain Rating Scale-11 (NPRS-11) in which lack of pain was scored 0 and the most severe pain -10. Moreover, the presence of nausea or/and vomiting was assessed. Using the simplified version of the Iowa Satisfaction with Anesthesia Scale (ISAS), the patients` satisfaction with anaesthesia was evaluated. The patients undergoing earlier procedures under general anaesthesia for various reasons were asked to compare and assess both forms of anaesthesia. The chief operator, blind to the details of anaesthesia, was postoperatively asked to assess intraoperative anaesthesia-related conditions according to the scale – bad, medium, good, or very good.

The obtained results were statistically analysed. The significance of intergroup differences was assessed using the t or ?2 test. P<0.05 was considered significant.

RESULTS

Each study group consisted of 30 patients. The procedures were carried out in 23 male and 27 female patients fulfilling ASA I-II criteria (Table 1). All patients underwent elective anaesthetic and surgical procedures. In control group, one difficult intubation was observed whereas high arterial pressure during 4 anaesthesias (13.3%). In study group, single paravertebral block-related adverse effects were noted: Horner syndrome – 1, vessel puncture during space identification – 1, pleural cavity puncture – 1, numbness of the right upper limb immediately after administration of the agent -1. Identification of the paravertebral space was difficult in 2 cases. Intraoperative hypotonia requiring intensive supply of fluids and ephedrine was observed during 2 anaesthesias in study group. All adverse effects were moderate and did not cause negative clinical sequels.

Mean arterial pressures in study group measured at 30 and 45 min of anaesthesia as well as immediately after surgery were significantly lower than those in control group; yet, the difference disappeared during further observation. No significant differences in HR and SpO2 were observed throughout the observation period. During anaesthesias in study group significantly lower average consumption of fentanyl and rocuronium was noted (Table 2).

The postoperative pain was significantly lower in study group; analgesics were required later and their mean dose was slightly lower (Table 3). Moreover, additional analgesia was administered less frequently (tramadol, ketoprofen), yet the difference recorded was not statistically significant (13.3% - vs 33.3% ). The incidences of postoperative nausea and vomiting during the three days of observation were higher, developed earlier and required higher doses of anti-emetics in control group (Table 4).

In control group, surgeons more frequently defined the anaesthesia-related conditions as very good, however, the difference was not significant (66.6 % vs 43.3 %).

The patients who had previously undergone surgeries under general anaesthesia considered the paravertebral block technique as better.

DISCUSSION

In recent years, increased interest in paravertebral block is observed, which is indirectly evidenced by a relatively high number of publications on this issue. Some of them are casuistic and report new possibilities of using the block for different types of surgeries, such as implantation of heart stimulating systems or cardioverters/defibrillators, coronary-artery bypasses and for thoracic, general, vascular or even plastic surgical procedures [4, 5, 6, 7]. This extremely safe method is a reasonable anaesthetic alternative for some procedures in patients with serious circulatory and respiratory diseases, including children [8, 9, 10]. On the other hand, there are few comparative studies assessing actual benefits of paravertebral blocks in concrete clinical situations. Cholecystectomies performed in the epigastrium and other biliary procedures generate severe postoperative pain and predispose to postoperative nausea and vomiting. Block anaesthesia techniques in such situations seem extremely desirable and are widely recommended [11].

In our study, both methods of anaesthesia enabled classic cholecystectomies. The paravertebral block anaesthesia was stable and safe for patients and transient slight decreases in arterial pressures might have resulted from the sympathetic response, which usually accompanies the block [2, 12, 13]. Paravertebral block provided proper intraoperative analgesia in over 80% of patients. In 5 cases, additional supply of fentanyl in the reduced dose was necessary during deep preparation of the gallbladder. The block resulted in almost two-fold lower severity of postoperative pain, which was observed throughout the observation period (3 days). This evidences high efficacy of unilateral paravertebral block in classic cholecystectomy. In the vast majority of cases, blockage of the spinal nerves and visceral nerve on the dependent side was sufficient. Thus, it is likely that the spread of the local anaesthetic agent from the place of administration (along the anterior surfaces of vertebral bodies to the opposite side) is common and may result in complete blockage of the conduction pathway to the visceral plexus [12, 13]. Bilateral paravertebral blocks provided even better analgesic effects, which in laparoscopic procedures may markedly decrease postoperative pain sensations [14]. Beneficial analgesic effects of paravertebral blocks were also reported in partial resections of the liver [15].

Postoperative nausea and/or vomiting after biliary surgeries and ways to prevent them have been addressed to for many years [16, 17, 18]. In our study, this complication was less common in patients undergoing paravertebral blocks. In our opinion, avoidance of intraoperative opioids directly affected such favourable effects. It was demonstrated that thoracic paravertebral block during laparoscopic cholecystectomy and other hepatic procedures substantially decreased the incidence of postoperative nausea and vomiting [14, 15].

According to patients, paravertebral block anaesthesia was better compared to anaesthetic procedures without blocks as their basic expectations were met (lack of persistent pain and vomiting after surgery). Similar findings were earlier reported in relation to mastectomies [2]. Moreover, good assessment of surgeons, slightly shorter duration of procedures as well as lower consumption of muscle relaxants should be stressed. These findings might be accidental yet they are also likely to have resulted from actual improvement of surgical conditions (relaxation and full analgesia within the abdominal integuments due to spinal nerve blockage). In our opinion, the results should be verified in more comprehensive studies. It is highly likely that paravertebral block before cholecystectomy may affect favourably the risk of persistent neuropathic pain after such procedures, as in cases of persistent chronic syndrome after mastectomy [19, 20].

CONCLUSIONS

1. General anaesthesia supplemented with unilateral thoracic paravertebral block provides good conditions for classic cholecystectomy.

2. Paravertebral block substantially improves the quality of postoperative analgesia, reduces the incidence of postoperative nausea and vomiting, and improves the patients` comfort.

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REFERENCES

1.   Najarian MM, Johnson JM, Landercasper J, Havlik P, Lambert PJ, McCarthy D: Paravertebral block: an alternative to general anesthesia in breast cancer surgery. Am Surg 2003; 69: 213-218.

2.   Paleczny J, Loniewska-Paleczny E, Pysz M, Hura G: Porównanie zastosowania piersiowej blokady przykregowej iogólnego wgruczolu piersiowego. Anaesthesiol Intensive Ther 2005; 37, 12-16.

3.   Eason MJ, Wyatt R: Paravertebral thoracic block – aAnaesthesia 1979; 34: 638-642.

4.   Tsai T, Rodriguez-Diaz C, Deschner B, Thomas K, Wasnick JD: Thoracic paravertebral block for implantable cardioverter-defibrillator and laser lead extraction. J Clin Anesth 2008; 20: 379-382.

5.   Mehta Y, Arora D, Sharma KK, Mishra Y, Wasir H, Trehan N: Comparison of continuous thoracic epidural and paravertebral block for postoperative analgesia after robotnic - assisted coronary artery bypass surgery. Ann Card Anaesth 2008; 11: 91-96.

6.   Falkensammer J, Hakaim AG, Klocker J, Biebl M, Lau LL, Neuhauser B, Mordecai M, Crawford C, Greengrass R: Paravertebral blockade with propofol sedation versus general anesthesia for elective endovascular abdominal aortic aneurysm repair. Vascular 2006; 14:17-22.

7.   Rudkin GE, Gardiner SE, Cooter RD: Bilateral thoracic paravertebral block for abdominoplasty. J Clin Anesth 2008; 20: 54-56.

8.   Basagan-Mogol E, Turker G, Yilmaz M, Goren S: Combination of apsoas compartment, sciatic nerve, and TI2-Ll paravertebral blocks for femoropopliteal bypass surgery in apatient. J Cardiothorac Vasc Anesth 2008; 22: 337-339.

9.   Serpetinis E, Bassiakou E, Xanthos T, Baltatzi L, Kouta A: Paravertebral block for open cholecystectomy in patients with cardiopulmonary pathology. Acta Anaesthesiol Scand 2008; 52: 872-873.

10.  Berta E, Spanhel J, Smakal 0, Smolka V, Gabrhelik T, Lonnqvist PA: Single injection paravertebral block for renal surgery in children. Paediatr Anaesth 2008; 18: 593-597.

11.  Zalecane postepowanie przeciwbólowe wpooperacyjnym wedlug Krajowego Nadzoru Specjalistycznego wanestezjologii iterapii. Ordynator Leków 2005; 11-12: 49-50.

12.  Richardson J, Lonnqvist PA: Thoracic paravertebral block. Br J Anaesth 1998; 81: 230-238.

13.  Hilgier M, Rykowski J: Blokady splotu trzewnego iów trzewnych. Blokady ukladu wspólczulnego (Red.: M. Hilgier). a-medica press, Bielsko-Biala, 1995: 98-117.

14.  Naja MZ, Ziade Mp, Lonnqvist PA: General anaesthesia combined with bilateral paravertebral blockade(T5-6) vs general anaesthesia for laparoscopic cholecystectomy: arandomized clinical trial. Eur J Anaesthesiol 2004; 21: 489-495.

15.  Moussa AA: Opioid saving strategy: bilateral single-site thoracic paravertebral block in right lobe donor hepatectomy. Middle East J Anesthesiol 2008; 19: 789-801.

16.  Karanicolas PJ , Smith SE, Kanbur B, Davies E, Guyatt GH: The impact of prophylactic dexamethasone on nausea and vomiting after laparoscopic cholecystectomy: areview and meta-analysis. Ann Surg 2008; 248: 751.

17.  Erhan Y, Erhan E, Aydede H, Yumus 0, Yentur A: Ondansetron, granisetron, and dexamethasone compared for the prevention of postoperative nausea and vomiting in patients undergoing laparoscopic cholecystectomy: Aplacebo-controlled study. Surg Endosc 2008; 22: 1487-1492.

18.  Ozturk T, Kaya H, Aran G, Aksun M, Savaci S: Postoperative beneficial effects of esmolol in treated hypertensive patients undergoing laparoscopic cholecystectomy. Br J Anaesth 2008; 100: 211-214.

19.  Paleczny J, Pysz M: Ocena wplywu piersiowej blokady przykregowej na przewlekly ból po mastektomii. Ból 2005; 4: 17-22.

20.  Kairaluoma PM, Bachmann MS, Rosenberg PH, Pere PJ: Preincisional paravertebral block reduces the prevalence of chronic pain after breast surgery. Anesth Analg 2006; 103: 703-708.

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Address:

*Jerzy Paleczny
ul. Mieszka I 11/4, 43-300 Bielsko-Biała
tel.: 0-33 822 73 87, 0-606 257 702
e-mail: j.pal@wp.pl

Received: 12.12.2008
Accepted: 10.02.2009