Comparison of Three Different Analgesic Protocols During Shockwave Lithotripsy

Abstract

Background and Purpose:

Shockwave lithotripsy (SWL) is one of the most important treatment modalities for urinary stone disease. The procedure may cause pain, and patient relaxation and cooperation are crucial in maintaining stone localization for optimal fragmentation and patient comfort during the procedure. As yet, there is not a standard analgesic protocol for patients undergoing SWL. We aimed to use three different analgesic agents and compare their efficacy during SWL in this study.

Patients and Methods:

Written informed consents were obtained from 95 patients with kidney stones, and they were randomized to receive lornoxicam (group L, n=32 patients), paracetamol (group P, n=31 patients), and tramadol with a patient-controlled analgesia device (group T, n=32 patients). All groups received patient-controlled analgesia with tramadol during the SWL procedure. The intensity of pain was evaluated with a visual analog scale (VAS).

Results:

The mean age of the patients was 41.87±16.53 years, 44.07±11.48 years, and 41.24±14.82 years in group L, group P, and group T, respectively. No significant differences were found between the three groups concerning patient age, stone location, or session duration (P>0.05). The mean VAS scores and analgesic consumption were lower in group L compared with other groups (P<0.05).

Conclusion:

The results of this study showed that additional administration of analgesics was decreased with intravenous lornoxicam in comparison with paracetamol and only tramadol.

Introduction

U rolithiasis is known to be an old disease of humans and remains a major issue regarding health and well-being today. The prevalence rate of kidney stones ranges between 8% and 19% in males and 3% and 5% in females in Western countries.¹ As has been shown in previous population-based studies, the prevalance of urinary stones has been increasing over the past 30 years in both males and females.² In addition to its significant medical expenditure, the high recurrence rate, which is more than 50% after 10 years, is another important concern.^3,4

As a result of these issues, many physicians and patients are trying to find new and effective analgesic protocols during renal colic, promote stone passage or stone dissolution, and prevent stone recurrence. Although various surgical approaches, such as percutaneous nephrolithotomy, retrograde intrarenal surgery, and open or laparoscopic stone surgery, are currently available in the management of renal stones, it is widely accepted that shockwave lithotripsy (SWL) is the standard treatment for patients with upper urinary tract stones with a diameter up to 2 cm.⁵ After SWL treatment, stone-free rates have been reported between 45% and 95%.^6
–8

Although SWL is a noninvasive and safe procedure, a number of complications may occur during or after SWL. The pain has been an important problem during the procedure and can affect the success rate of SWL negatively.⁹ For maintenance of the stone in the target area and optimal fragmentation of the stone during SWL, general well-being, comfort, and cooperation of the patient are very important factors. To accomplish these conditions, usually an appropriate analgesic with minimal side effects is used during the SWL procedure. Many analgesic medications, including opioids, nonsteroidal anti-inflammatory drugs (NSAIDS), local anesthetic agents, and a number of combinations have been used during SWL by various techniques, such as general and regional anesthesia, subcutaneous and intravenous injections, patient-controlled analgesia (PCA), and monitored anesthesia care.^9

–12 Another popular technique, multimodal analgesia, which uses a combination of analgesic drugs with different pharmacologic characteristics, increases the quality and efficacy of the treatment and can also decrease the incidence of side effects.

Because the guidelines for pain management during SWL have not been established, the aim of this study was to investigate and compare the effectiveness, adverse effects, and patient satisfaction of three different analgesic agents for pain management during SWL.

Patients and Methods

Between January 2005 and December 2007, a total of 95 patients (American Society of Anesthesiologists physical status I, II) who underwent SWL for kidney stones were included in the study. The approval of the hospital ethics committee and written informed consents were obtained from patients. Patients were evaluated with a physical examination, plain abdominal radiography, urine analysis, routine hematologic and biochemical analysis, and urinary system ultrasonography or intravenous urography.

In this prospective controlled study, the patients were randomized into three groups. Group L (n=32), patients received intravenous (IV) lornoxicam (8 mg) 60 minutes before SWL; group P (n=31) patients received IV paracetamol (1 g) within 15 minutes, 60 minutes before SWL; and group T (control group, n=32) patients received IV tramadol via PCA device during the procedure. All patients were given IV PCA (capable of delivering a bolus dose of 10 mg of tramadol on demand with a basal infusion dose of 5 mg/h and a lockout period of 10 min) during SWL. All patients received no other premedication except lornoxicam and paracetamol, and they were advised not to eat or drink for at least 4 hours before the procedure.

SWL was performed by the same physician. The SWL was performed with the PCK stonelith device (PCK Electronics Inc. Ltd., Ankara, Turkey). The device has a computer-based control system that uses electrohydrolic shockwave generation through the underwater discharge of an electric gap. The pulse rate of shockwaves was adjusted between 90 to 100/min for all patients. SWL therapy is usually started at a low voltage of 14 kV until the patient becomes accustomed to the shocks, and then the voltage is gradually increased to a maximum of 23 kV.

The exclusion criteria were neurologic conditions such as spinal cord injury and multiple sclerosis, bleeding disorders, serum creatinine level >200 mol/L, peptic ulcer disease, age less than 18 years, weight less than 50 kg or more than 100 kg, active urinary tract infection, analgesic/narcotic dependency, chronic use of some drugs such as antidepressants, histamine blockers, and anxiolytics, and a history of an allergic reaction to the medications. Arterial blood pressure, heart rate, respiratory rate, and oxygen saturation were recorded before the procedure, after sedation, at the first minute, and every 5 minutes during the procedure.

The pain level of the patients during SWL was evaluated at 1 minute and then every 5 minutes with a visual analog scale (VAS) by using a 10-cm linear analog scale (0=no pain, 10=very severe pain). During the SWL procedure, the method of pain assessment was explained to the patients.

Statistical analysis

The Kolmogorov-Smirnov test was used to evaluate whether the distribution of variables were normal. The analysis of variance test was used to compare all continuous variables among groups. For multiple comparisons, the Scheffe test was used. The chi-square test was used to compare the sex among three groups. One-way repeated measures analysis of variance was used to compare the variables among five periods separately for three groups. For multiple comparisons, the least significant difference test was used. Two-way repeated measures analysis of variance was used to compare the alteration of five periods among three groups. For multiple comparisons, Scheffe and Tamhane tests were used. The continuous variables were presented as the mean±standard deviation; categorical variables were presented as count and percentage. A P value of<0.05 was considered significant. Analyses were performed using commercial software (PASW ver.18, SPSS Inc, Chicago IL.).

Results

Of the 95 patients in the study group, 73 were men and 22 were women, with a mean age of 42±14.2 years. The mean age of the patients was 41.87±16.53 years, 44.07±11.48 years, and 41.24±14.82 years in group L, group P, and Group T, respectively (P>0.05). All of the stones were located in the kidney with a mean diameter of 9.5±4.2 mm (range 5–15 mm). The stone was in the left kidney in 49 (57.6%) and in the right kidney in 46 (42.4%) of the patients. The clinical and demographic characteristics of the patients are presented in Table 1. No significant differences were found between the three groups concerning patient age, stone burden, stone location, or session duration of the SWL (all P>0.05; Table 1). The number of shocks was not statistically different between the groups. At the end of the SWL, the mean VAS scores were 2.46±2.28, 3.66±2.45, and 4.77±2.75 in group L, group P, and group T, respectively.

Table 1.

Comparison of Clinical Parameters for Both Groups During Shockwave Lithotripsy

Variables	Group L (PCA) (n=32) Mean±SD	Group P (PCA) (n=31) Mean±SD	Group T (PCA) (n=32) Mean±SD	F	P
Age	41.87±16.53	44.07±11.48	41.24±14.82	0.320	0.727
Number of shockwaves	1950.0±162.6	2000.0±0	1960.3±131.2	1.391	0.254
Frequence of PCA administration	0.66±0.55	1.03±0.75	1.09±0.71	3.620	0.031
Frequence of PCA demand	2.10±3.75	7.74±12.62	10.41±11.78	5.170	0.007
PCA (mg)	13.61±9.87	21.84±14.33	22.81±13.65	4.670	0.012

SD=standard deviation; PCA=patient-controlled analgesia.

The mean pain score was not statistically significant between groups at baseline, 5 and 10 minutes (P=0.114, P=0.236 and P=0.659, respectively). There was a significant difference, however, between the groups at 15 and 20 minutes (P=0.034, and P=0.003. respectively). At the end of the SWL treatment, the mean pain score was lower in group L in comparison with other groups. There was not a statistically significant difference between pain levels of group P and group T (Table 2) (Fig. 1). The VAS score in group L was lower than that in the group P and group T at 5, 10, 15, and 20 minutes, but the differences between the groups were statistically significant only at 15 and 20 minutes (P<0.05).

FIG. 1.

The alteration of the visual analog scale, according to groups.

Table 2.

The Comparison of the Groups in Terms of Visual Analog Scale, Respiratory Rate, Blood Pressure, and Heart Rate

Variables	Periods	Group L (PCA) (n=32) Mean±SD	Group P (PCA) (n=31) Mean±SD	Group T (PCA) (n=32) Mean±SD	^a F	P
Visual analog scale 0–10)	Baseline	0.14±0.58	0.25±0.62	0±0	2.222	0.114
	5^th min	0.93±1.16	1.53±2.03	0.94±1.45	1.465	0.236
	10^th min	1.86±1.87	2.25±2.55	2.38±2.41	0.419	0.659
	15^th min	2.03±2.08	3.03±2.47	3.62±2.52	3.511	0.034
	20^th min	2.48±2.28	3.66±2.45	4.77±2.74	6.274	0.003
		^bF=7.174, P=0.001	^bF=14.586, P<0.001	^bF=22.623, P<0.001
			^cF=2.209, P=0.116
Respiratory rate (breaths/min)	Baseline	18.50±2.79	20.79±2.54	20.35±3.52	5.134	0.008
	5^th min	19.47±3.41	21.31±2.21	20.91±2.98	3.418	0.037
	10^th min	19.87±3.27	21.24±2.13	21.62±4.08	2.489	0.089
	15^th min	19.39±3.24	20.86±2.81	22.47±2.94	8.563	<0.001
	20^th min	19.93±3.47	20.38±2.71	22.39±3.12	5.339	0.007
		^bF=2.955, P=0.040	^bF=1.479, P=0.238	^bF=3.783, P=0.014
			^cF=8.571, P<0.001
Systolic blood pressure (mm Hg)	Baseline	127.87±18.91	133.45±18.38	132.71±21.57	0.739	0.481
	5^th min	129.94±22.38	135.41±18.62	131.74±19.51	0.573	0.566
	10^th min	132.16±22.24	138.97±25.35	134.06±21.00	0.715	0.492
	15^th min	130.26±19.08	139.31±25.20	136.82±23.41	1.296	0.279
	20^th min	132.52±19.66	142.90±28.89	134.35±21.56	1.598	0.208
		^bF=702, P=0.598	^bF=1.474, P=0.240	^bF=579, P=0.681
			^cF=1.249, P=0.292
Diastolic blood pressure (mm Hg)	Baseline	70.94±12.32	78.24±13.78	76.21±14.90	2.338	0.102
	5^th min	73.25±15.07	79.48±12.11	77.38±15.63	1.486	0.232
	10^th min	74.97±13.78	81.45±13.93	78.94±18.45	1.338	0.267
	15^th min	71.87±18.38	80.97±15.48	81.18±19.94	2.677	0.074
	20^th min	76.14±14.54	80.59±17.16	80.58±15.79	0.768	0.467
		^bF=1.927, P=0.137	^bF=0.861, P=0.501	^bF=3.197, P=0.028
			^cF=2.231, P=0.114
Heart rate (beats/min)	Baseline	79.53±11.51	82.21±16.91	85.56±15.98	1.350	0.264
	5^th min	77.81±10.32	79.38±15.56	79.91±11.25	0.250	0.780
	10^th min	77.13±9.64	79.48±17.47	78.29±11.55	0.246	0.782
	15^th min	75.23±9.01	77.14±16.80	76.44±10.66	0.183	0.833
	20^th min	75.62±9.63	75.79±16.96	78.26±12.47	0.370	0.692
		^bF=6.555, P=0.001	^bF=8.897, P<0.001	^bF=4.829, P=0.005
			^cF=0.297, P=0.744
Oxygen saturation (SPO₂%)	Baseline	98.00±1.69	97.97±1.35	98.12±1.70	0.080	0.923
	5^th min	98.03±1.75	98.00±1.51	98.06±1.76	0.010	0.990
	10^th min	97.81±1.73	97.66±1.37	98.18±1.64	0.899	0.411
	15^th min	97.58±1.77	97.72±1.46	97.94±1.76	0.383	0.683
	20^th min	97.59±1.63	97.66±1.47	97.97±1.96	0.306	0.737
		^bF=3.073, P=0.035	^bF=0.758, P=0.563	^bF=1.131, P=0.363

The comparison among three groups separately for five periods.

The comparison among five periods separately for three groups.

The comparison of the alteration of five periods among three groups.

PCA=patient-controlled analgesia; SD=standard deviation.

The frequencies of PCA demands and administrations were also recorded. In the statistical analysis, it was found that required and administered analgesic dosage were lower in group L than group T (P=0.031, P=0.007, and P=0.012 respectively). There was not a statistical significant difference, however, between group P and other groups (Table 1). The amount of energy delivered to the patients was similar in all groups.

According to baseline parameters, heart rate, blood pressure, and oxygen saturation were lower at the end of the procedure in all groups. These differences, however, were not statistically significant (P>0.05) (Table 2). When the oxygen saturation, respiratory rates, and heart rates were compared at baseline and after 20 minutes, there was no significant difference between the groups (P>0.05).

Satisfactory stone fragmentation was achieved in all groups. The diameters of stones ranged from 5 to 15 mm for all groups. After SWL treatment, 22 (68.8%) of the 32 patients were stone-free by plain radiography, 6 (18.75%) had residual fragments, and 4 (12.5%) had no sign of stone disintegration in group L. In group P, 20 (64.5%) of the 31 patients were stone-free by plain radiography, 6 (19.35%) had residual fragments, and 5 (16.1%) had no sign of stone disintegration. In group T, 21 (65.6%) of the 32 patients were stone-free by plain radiography, 5 (15.6%) had residual fragments, and 6 (18.75%) had no sign of stone disintegration. Although the stone-free rate was greater and the percentage of residual fragments was lower in group L than in group P and group T, these differences were not statistically significant (P=0.934).

The incidence of nausea and vomiting was higher in group L, and an antiemetic was needed by only one patient in this group. Meanwhile, no patient needed an antiemetic in other groups (Table 3). None of the patients had gastrointestinal side effects (gastric irritation, gastrointestinal bleeding), and systemic adverse effects were not statistically significant between the groups (P>0.05).

Table 3.

Frequency of Side Effects

	Group L (n=32) n (%)	Group P (n=31) n (%)	Group T (n=32) n (%)	X ²	P
Nausea	4 (12.5)	3 (9.7)	2 (6.3)	0.751	0.687
Vomiting	1 (3.1)	0 (0)	0 (0)	2.197	0.333
Skin changes	2 (6.3)	2 (6.3)	3 (9.4)	0.276	0.871
Hematuria	27 (84.4)	28 (90.3)	29 (90.6)	0.744	0.689
Stone-free rates	22 (68.8)	20 (64.5)	21 (65.6)	0.137	0.934
Gastrointestinal effects	1 (3.1)	0 (0)	0 (0)	2.197	0.333

Discussion

The main goal of stone treatment with SWL is to provide maximum stone-free rates and minimum morbidity for the patients. Several surgical approaches, such as endoscopic interventions and open surgical procedures, have been used in the management of urinary system stones, but from 1980 until now, SWL has become the first-line treatment for urinary stones in adults and children because of its noninvasive nature, efficacy, and minimal morbidity.

Approximately 80% to 85% of the renal stones are satisfactorily managed with SWL.¹³ After SWL procedure, the stones that are disintegrated into sandlike fragments are excreted with normal urinary drainage spontaneously. In the present study, group L had a greater stone-free rate and lower percentage of residual fragments than group P and group T; however, these differences were not statistically significant (P>0.05).

Although SWL is an effective method for the management of upper urinary system stone disease, it may cause severe pain during the procedure. It has been reported that the majority of patients who undergo SWL do not tolerate this procedure without analgesia or sedation. The importance of patient comfort and cooperation during SWL procedure for maintenance of the stone localization, optimal fragmentation of the stone, and for success of SWL has been emphasized in a number of previous studies. In this context, numerous studies have been performed to determine the most suitable drug for this procedure and, as mentioned above, several drugs, such as midazolam, NSAIDs, sufentanyl, fentanyl, dexmedetomidine, ketamine, desflurane, local anesthetic creams, subcutaneous prilocaine, different combinations, and propofol have been the focus of previous studies.^14

–18 Despite numerous studies, to date, guidelines for pain management during SWL have not been well established, and for this reason, the search for the ideal analgesic drug continues.

Although several previous studies have compared different local and systemic analgesia regimens for pain relief during SWL, opioids are the most commonly used analgesics for this aim. Tramadol, which is an opioid analgesic, is a synthetic 4-phenyl-piperidine analog of codeine, and it is a centrally acting analgesic for relief of moderate to severe pain.¹⁹ The efficacy of tramadol during SWL has been reported in a extremely limited number of studies.²⁰ Another well-known analgesic group that is used in the management of pain is NSAIDs. NSAIDS, especially tenoxicam, piroxicam, and diclofenac sodium, have been used in relieving pain during SWL.^16,21,22 Paracetamol has a central analgesic effect that is mediated through activation of descending serotonergic pathways.²³ The mechanism of action of paracetamol, however, is still not completely understood. Despite reports of various studies comparing different analgesic techniques during SWL, guidelines for pain management during the procedure are not established.

In our study, lower VAS pain scores that were detected in the lornoxicam+tramadol (PCA) group patients suggest that lornoxicam (in combination with tramadol via PCA) may provide important advantages over paracetamol (combination with tramadol via PCA). The efficacy of lornoxicam has been shown in postoperative pain, but there is a limited number of study on its efficacy in SWL.

Although there are numerous studies comparing lornoxicam with other analgesics during various types of surgery in the literature, to our knowledge, there are only two studies on its effect during SWL. Bilir and associates²⁴ compared 8 mg lornoxicam with 20 mg tenoxicam administered before the procedure and found that lornoxicam markedly decreased opioid consumption without increasing side effects. In another previous study, the effects of two different doses of pretreatment-applied lornoxicam on pain during SWL, side effects, and patient comfort were investigated.²⁵ At the end of the study, satisfactory analgesia and a decrease in fentanyl consumption were seen with both doses of lornoxicam. In addition to the increase in satisfaction of the patient and sedation during the procedure, the incidence of nausea and vomiting decreased parallel to the decrease in fentanyl consumption. As a result of that study it was stated that the 8-mg dose of lornoxicam was enough for effective and adequate analgesia, but also increasing the dose to 16 mg did not influence either VAS score or analgesic consumption.

In many studies, IV paracetamol had been combined with injectable opioids, and it has been found that paracetamol reduced the necessity for opioids.^26,27 The analgesic efficacy of IV paracetamol had been reported in two studies during SWL.^28,29 In one of these studies, it was suggested that paracetamol, lornoxicam, and tramadol can be safely and efficiently preferred in pain control throughout the SWL procedure.²⁸ In the other study, some predictive risk factors for pain during SWL treatments were found, which were young age, anxious and depressed patients, previous SWL treatment, and homogeneous stones.²⁹

There are two important receptor types in perception of pain during SWL, which are cutaneous superficial skin nociceptors and visceral nociceptors. Namely, these receptors are periostal, pleural, peritoneal, and/or musculoskeletal pain receptors. NSAIDs provide pain relief by their anti-inflammatory effect caused by prostaglandin synthesis inhibition and are effective via oral, intramuscular, and rectal routes. The adverse effects of the analgesics during SWL range between 3% and 11% in different studies.²⁵ NSAIDs have adverse effects, such as nausea and vomiting, mild orthostatic hypotension, renal dysfunction, gastric irritation, coagulation disorder, gastrointestinal bleeding, dizziness, and respiratory depression.

Lornoxicam, which is a short-acting NSAID form from the oxicam goup, has spinal nociceptor activity and Cox-1 and Cox-2 inhibitory properties as well. According to the results of experimental studies, it has an analgesic effect of 12 times higher than tenoxicam and 3 times higher than piroxicam.³⁰ It has also been shown that lornoxicam inhibited the cyclooxygenase enzyme 100 times more than piroxicam.³⁰ Different aspects of lornoxicam in comparison with other oxicams are its high-efficiency potential, good gastrointestinal tolerance, and a short plasma half-life of 3 to 5 hours. Therefore, a short-acting NSAID may be suitable to decrease the incidence of side effects, provide early discharge, and prevent rehospitalization of the patient while providing good analgesia during the procedure. Apparently for these reasons, lornoxicam can be a good alternative to the current NSAIDs used for SWL analgesia. It has also been reported that lornoxicam does not exert a serious nephrotoxic effect and does not produce an important change on the hemostatic cascade, except for a mild prolongation of the clotting time.²⁸

Despite their effectiveness, because of use of opioids, many adverse effects, such as respiratory depression, bradycardia, hypotension, nausea, vomiting, pruritus, and prolonged recovery time can be seen. It has been revealed that lornoxicam is an effective analgesic with lower side effects than opioids, especially with regard to hemodynamic instability and respiratory depression. In this study, the incidence of adverse effects was greater in group L in comparison with other groups, but these differences were not statistically significant. This study also revealed that additional analgesic consumptions were decreased when we compared the IV lornoxicam+tramadol (PCA) analgesia group with the paracetamol+tramadol (PCA) and control (tramadol [PCA]) group.

As a result, the combination of lornoxicam and tramadol, which is one of the analgesic drug combinations known as multimodal analgesic, showed much more efficacy againist acute pain due to SWL treatment in comparison other groups in this study. On the other hand, although there was no difference with respect to side effects and hemodynamic parameters among all the three groups, it may be speculated that the combination of lornoxicam and tramadol may be preferred instead of other combinations in pain control during SWL according to the results of this study. It should also be stated that there is a need for more comprehensive studies to evaluate the efficacy of multimodal analgesics in the future.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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