The control of post-thoracotomy pain. A comparative evaluation of thoracic epidural fentanyl infusions and cryo-analgesia

Intercostal Cryo Nerve Block in Minimally Invasive Cardiac Surgery: The Prospective Randomized FROST Trial

INTRODUCTION

Intercostal cryo nerve block has been shown to enhance pulmonary function recovery and pain management in post-thoracotomy procedures. However, its benefit have never been demonstrated in minimal invasive thoracotomy heart valve surgery (Mini-HVS). The purpose of the study was to determine whether intraoperative intercostal cryo nerve block in conjunction with standard of care (collectively referred to hereafter as CryoNB) provided superior analgesic efficacy in patients undergoing Mini-HVS compared to standard-of-care (SOC).

METHODS

FROST was a prospective, 3:1 randomized (CryoNB vs. SOC), multicenter trial in patients undergoing Mini-HVS. The primary endpoint was the 48-h postoperative forced expiratory volume in 1 s (FEV1) result. Secondary endpoints were visual analog scale (VAS) scores for pain at the surgical site and general pain, intensive care unit and hospital length-of-stay, total opioid consumption, and allodynia at 6 months postoperatively.

RESULTS

A total of 84 patients were randomized to the two arms of the trial CryoNB (n = 65) and SOC (n = 19). Baseline Society of Thoracic Surgeons Predictive Risk of Mortality (STS PROM) score, ejection fraction, and FEV1 were similar between cohorts. A higher 48-h postoperative FEV1 result was demonstrated in the CryoNB cohort versus the SOC cohort (1.20 ± 0.46 vs. 0.93 ± 0.43 L; P = 0.02, one-sided two-sample t test). Surgical site VAS scores were similar between the CryoNB and SOC cohorts at all postoperative timepoints evaluated, but VAS scores not related to the surgical site were lower in the SOC group at 72, 94, and 120 h postoperatively. The SOC cohort had a 13% higher opioid consumption than the CryoNB cohort. One of 64 CryoNB patients reported allodynia that did not require pain medication at 10 months.

CONCLUSIONS

The results of FROST demonstrated that intercostal CryoNB provided enhanced FEV1 score at 48 h postoperatively with optimized analgesic effectiveness versus SOC. Future larger prospective randomized trials are warranted to determine whether intercostal CryoNB has an opioid-sparing effect in patients undergoing Mini-HVS.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02922153.

Management of Pain in the Critically Ill

Analgesia for critically ill patients can be provided most effectively by the use of modern techniques. Under standing of the anatomical pathways for nociceptive sig nal transmission allows the use of techniques that mod ulate or block nociceptive information at several levels (periphery, spinal cord, and systemic). A comprehen sive discussion of analgesic techniques at each level is presented. Formulation of a treatment plan is discussed. Several examples are presented to show the decision- making process for the use of modern analgesic tech niques in critically ill patients.

Painful neuromas

OBJECTIVES

To perform a topical review of the published literature on painful neuromas.

METHODS

A MEDLINE search was performed using the MESH terms "neuroma", "pain", "diagnosis", and "treatment" for all dates.

RESULTS

Acoustic neuromas and intraabdominal neuromas were excluded from a total of 7616 articles. The reference lists from these articles were further reviewed to obtain other relevant articles.

DISCUSSION

Neuromas develop as part of a normal reparative process following peripheral nerve injury. Painful neuromas can induce intense pain resulting in immense suffering and disability. MRI aids the diagnosis, but, ultrasound imaging allows cost effective accurate diagnosis and localization of neuromas by demonstrating their direct contiguity with the nerve of origin. Management options for painful neuromas include pharmacotherapy, prosthetic adjustments, steroid injection, chemical neurolysis, cryoablation, and radiofrequency ablation. Ultrasound imaging guidance has improved the success in localizing and targeting the neuromas. This review discusses the patho-physiology and accumulated evidence for various therapies and the current percutaneous interventional management options for painful neuromas.

[Continuous paravertebral block as an analgesic method in thoracotomy]

INTRODUCTION

Open thoracotomy is one of the surgical procedures that is still very painful in the postoperative period, which, in this type of surgery can have on respiratory function and subsequent recovery of the patient.

PATIENTS AND METHOD

The aim of the study is to assess continuous paravertebral thoracic block as an analgesic technique in thoracotomy. A total of 139 patients undergoing pulmonary resection surgery by posterolateral thoracotomy received postoperative analgesia using a 1.5% lidocaine infusion (7-10 ml/h) through a thoracic paravertebral catheter for at least 48 h. Pain intensity measured on the visual analogue scale (VAS) both at rest (passive VAS) and during stimulated cough (active VAS) was recorded at time of discharge from the Recovery Unit, and on the second, third and fourth day post-surgery. Postoperative complications and the need for analgesic rescue were studied.

RESULTS

On discharge from recovery, 98.6% of the patients had mild pain (passive VAS <3), 1.4% had moderate pain (passive VAS 4-6) and none with severe pain (EVA >6); on the 2nd day post-surgery, 97.9% had mild pain, and 1.2% moderate pain; on the third day 98.6% had mild pain and 0.7% moderate pain; and on the 4th day 100% had mild pain. There were no complications arising from the analgesic technique.

CONCLUSIONS

Continuous thoracic paravertebral analgesia is effective and safe in controlling post-thoracotomy pain.

CT guided percutaneous cryoneurolysis for post thoracotomy pain syndrome: early experience and effectiveness

RATIONALE AND OBJECTIVES

The aim of this study was to determine the effect of cryoablation on pain levels in patients with histories of post-thoracotomy pain syndrome.

MATERIALS AND METHODS

Eighteen patients were included in this retrospective review. Preprocedural and immediate postprocedural pain scores were recorded, as well as several months after the procedures.

RESULTS

The average preprocedural pain score was 7.5 +/- 2.0, which decreased to 1.2 +/- 1.9 immediately after the procedure. After a mean follow-up period of 51 days, the average pain score was 4.1 +/- 1.7. The difference between preprocedural and postprocedural pain scores was statistically significant by Wilcoxon's rank sum test.

CONCLUSION

Cryoneurolysis of the intercostal nerves statistically significantly decreased pain scores in patients with post-thoracotomy pain syndrome.

Postthoracotomy pain management problems

Pain after thoracotomy is very severe, probably the most severe pain experienced after surgery. Thoracic epidural analgesia has greatly improved the pain experience and its consequences and has been considered the standard for pain management after thoracotomy. This view has been challenged recently by the use of paravertebral nerve blocks. Nevertheless, severe ipsilateral shoulder pain and the prevention of the postthoracotomy pain syndrome remain the most important challenges for management of postthoracotomy pain.

The benefits of adding epidural analgesia to general anesthesia: a metaanalysis

The purpose of this metaanalysis was to determine the benefits of postoperative epidural analgesia in patients operated on under general anesthesia. By searching the American National Library of Medicine's Pubmed database from 1966 to July 10, 2004, 70 studies were identified. These included 5402 patients, of which 2660 had had epidural analgesia. Epidural analgesia reduces the incidence of arrhythmia, odds ratio (OR) = 0.59 (95%CI = 0.42, 0.81, P = 0.001); time to tracheal extubation, OR = -3.90 h (95%CI = -6.37, -1.42, P = 0.002); intensive care unit stay, OR = -2.94 h (95%CI = -5.66, -0.22, P = 0.03); visual analogical pain (VAS) scores at rest, OR = -0.78 (95%CI = -0.99, -0.57, P < 0.00001) and during movement, OR = -1.28 (95%CI = -1.81, -0.75, P < 0.00001); maximal blood epinephrine, OR = -165.70 pg.ml(-1) (95%CI = -252.18, -79.23, P = 0.0002); norepinephrine, OR = -134.24 pg.ml(-1) (95%CI = -247.92, -20.57, P = 0.02); cortisol, OR = -55.81 nmol.l(-1) (95%CI = -79.28, -32.34, P < 0.00001); and glucose concentrations achieved, OR = -0.87 nmol.l(-1) (95%CI = -1.37, -0.37, P = 0.0006). It also reduces the first 24-h morphine consumption, OR = -13.62 mg (95%CI = -22.70, -4.54, P = 0.003), and improves the forced vital capacity (FVC), OR = 0.23 l (95%CI = 0.09, 0.37, P = 0.001) at 24 h. A thoracic epidural containing a local anesthetic reduces the incidence of renal failure: OR = 0.34 (95%CI = 0.14, 0.81, P = 0.01). Epidural analgesia may thus offer many advantages over other modes of postoperative analgesia.

Ultrasound-Guided Intercostal Nerve Cryoablation

Ultrasound technology has advanced regional anesthesia and pain management, by improving accuracy and reducing complication rates. We have successfully performed cryoablation of intercostal nerves with ultrasound guidance with no complications. Four patients with postthoracotomy pain syndrome had pain relief for at least 1 mo after selective cryoablation of intercostal nerves at the mid-axillary line. Visualizing the pleura during the procedure is the greatest benefit of using ultrasonography, especially in thin patients whose intercostal groove to pleural distance may be <0.5 cm. Although further studies are needed, we feel that this new technique should reduce the risk of pneumothorax as well as improve the success of cryoablation.

The changing practice of thoracic epidural analgesia in the United Kingdom: 1997-2004

The clinical governance framework and medico-legal climate in the United Kingdom has changed significantly in the past 7 years. We used a postal questionnaire to survey thoracic epidural practice in the United Kingdom in 1997 and repeated this survey in 2004. The response rate to both surveys was 59-60%. There has been considerable change in respect of taking specific consent for thoracic epidural analgesia (24% in 1997, 74% in 2004), awake epidural cannulation (40% in 1997, 84% in 2004), availability of an acute pain service (47% in 1997, 95% in 2004) and HDU-only nursing of patients (63% in 1997, 30% in 2004). Of the 2004 respondents, < 1% used the newer, less toxic local anaesthetics, 49% would consider inserting a thoracic epidural in patients receiving clopidogrel, and 34% would consider inserting a thoracic epidural in patients receiving both aspirin and clopidogrel. A central register of thoracic epidural complications would assist in further developing practice.

Efficacy of Methods of Intercostal Nerve Blockade for Pain Relief After Thoracotomy

Intercostal nerve blockade for postthoracotomy pain relief can be accomplished by continuous infusion of local anesthetics through a catheter in the subpleural space or through an interpleural catheter, by cryoanalgesia, and by a direct intercostal nerve block. A systematic review of randomized studies indicates that an extrapleural infusion is at least as effective as an epidural and significantly better than narcotics alone. The other techniques of intercostal blockade do not offer an advantage over narcotics alone.

The effects of cryoanalgesia combined with thoracic epidural analgesia in patients undergoing thoracotomy

This study was performed to evaluate the effects of cryoanalgesia combined with thoracic epidural analgesia on pain and respiratory complications in patients undergoing thoracotomy. Ninety patients were prospectively randomised to epidural analgesia alone (n = 45) or epidural analgesia and cryoanalgesia combined (n = 45). We monitored the use of rescue pain medication and changes in forced vital capacity and forced expired volume in 1 s, and recorded pain and opioid-related side-effects during the immediate postoperative period. The incidence of post-thoracotomy pain and numbness were also assessed up to the sixth month after surgery. Cryoanalgesia combined with thoracic epidural analgesia was associated with earlier recovery in pulmonary function, less pain during movement and a lower daily requirement for rescue analgesia one week after surgery. However, the combination of cryoanalgesia and epidural analgesia failed to decrease the incidence of long-term pain and numbness. In view of its associated long-term morbidity, cryoanalgesia combined with thoracic epidural analgesia is not recommended for patients undergoing thoracotomy.

Effect of cryoanalgesia combined with intravenous continuous analgesia in thoracotomy patients

Fifty patients undergoing thoracotomy was studied to compare the effects of cryoanalgesia combined with intravenous continuous analgesia (IVCA). Patients were randomized into two groups: IVCA group and IVCA-cryo group. Subjective pain intensity was assessed on a visual analogue scale at rest (VAS-R) and during movement (VAS-M). Analgesic requirements were evaluated over the 7 days following surgery. Forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) were measured before operation, on the 2nd and 7th postoperative days (POD). We interviewed patients by telephone to evaluate the prevalence of post-thoracotomy pain at the 1st, 3rd, and 6th months postoperatively. No significant differences were observed between the two groups with respect to postoperative pain, analgesic requirements, side effects, respiratory complications, or prevalence of post-thoracotomy pain. However, a significant increase in FVC and FEV1 was observed on the 7th POD in IVCAcryo group. The incidence of the post-thoracotomy pain at the 1st, 3rd, and 6th months postoperatively was 68, 60, and 44% in IVCA group, and 88, 68, and 28% in IVCAcryo group, respectively. Our study showed that cryoanalgesia combined with IVCA effectively restore respiratory function on 7th POD, but that it was not effective at reducing the incidence of post-thoracotomy pain.

Analgesia for trauma and burns

This article has described the physiologic impact of trauma- and burn-related pain as well as the effect of a clinician's choice of analgesic method, using the specific example of regional analgesia for pain caused by chest trauma. It has been observed that trauma exerts a holistic influence upon the organism, marshalling reflexes, multi-system physiologic stress responses, and psychologic responses--some adaptive and others maladaptive. There is reason to consider that timely analgesia can intervene in this dynamic process and interdict the establishment of a debilitated state. A key finding of these studies is that a report of pain relief may not be the best outcome measure since the choice of analgesic method(s) has a significant impact on the secondary effects of pain. Although extrapolated from studies of perioperative pain, findings do suggest that there may be a critical period of time during which the secondary effects of a painful stimulus may be attenuated or reversed. How long this period of reversibility exists has not been determined, so planning for the level and goals of analgesia intervention should occur early on. Analgesia should be viewed not only as a humanitarian gesture, but also a therapeutic maneuver with the goal being the early restoration of function and the mitigation of a chronic debilitated state. There is scattered evidence that regional analgesic techniques using local anesthetics have some advantages over other analgesic modalities, particularly in the trauma patient with pulmonary compromise; however, as with other medical interventions, one should develop a strategic plan of application which includes consideration of potential complications and side effects, in addition to the potential therapeutic effects. The traumatized body, as well as the attending physician, must deal with inflammation, the neurohumoral reaction, musculoskeletal reflex responses, and numerous other reactions designed to stabilize an acutely destabilized systemic entity. Multimodal analgesia, with the balanced use of systemic and regional medications, has given the best short- and long-term results in studies of postthoracotomy pain. The use of a similar combined plan for posttraumatic analgesia seems logical; however, many questions remain as yet unanswered. In particular, what are the optimal combinations of techniques/medications to employ to maximize analgesia and minimize secondary effects of trauma? Can an aggressive multimodal approach intervene effectively in the development of chronic pain states, and if so, for how long? What are the long-term benefits to be derived from making a significant impact on the stress response? Last, but not least, can analgesic interventions be shown to be cost-effective according to current societal pressures to reduce the cost of health care? These and other questions are not easy to answer. Trauma strikes, in a variable fashion, patients of all ages, with all forms of comorbidity, and is treated by a technology that continues to evolve. Previous research related to the effects of analgesic treatments has been hampered by the limitations that arise when isolated groups embark on vast projects with limited numbers of patients available. It is time for investigators at multiple centers to embark on coordinated efforts to address long-term questions related to trauma and the therapeutic efficacy of analgesia.

Introducing epidural fentanyl for on-ward pain relief after major surgery

BACKGROUND

Epidural opioids have been recommended for analgesia after major surgery. In this report we describe how we introduced a low-cost, on-ward, nurse-based acute pain service using epidural fentanyl after major surgery in the University Hospitals of Oulu and Kuopio.

METHODS

In order to evaluate the feasibility of epidural fentanyl infusion administered by ward nurses, we prospectively assessed pain and side effects during fentanyl infusion (median duration 41 h) after major surgery in 305 consecutive patients in Kuopio.

RESULTS

92% of the patients on the ward who had received epidural fentanyl infusion at 31-54 micrograms h-1 reported at most three episodes of severe pain (/Numerical Rating Scale > 3/ 10) during the initial postoperative days, but there were some patients (8%) who reported several episodes (> 3) of more severe pain (Numerical Rating Scale > 3). Three patients (0.9%) showed a diminished respiratory rate (< 10/min), but only one of them (0.3%) was somnolent. One other patient (0.3%) was not arousable until the cessation of infusion. Nausea and pruritus were minor problems in our patients, but a majority needed a urinary catheter.

CONCLUSION

With well-trained nurses, careful monitoring and appropriate protocols, epidural fentanyl infusion proved to be a feasible method for pain relief after major surgery on a surgical ward.

Interpleural or thoracic epidural analgesia for pain after thoracotomy. A double blind study

The analgetic effect of bupivacaine given epidurally or interpleurally after thoracotomy was investigated in a randomized, double blind, placebo controlled study. 32 patients with both an epidural and an interpleural catheter, were randomized to receive either interpleural or epidural analgesia. The interpleural group was given bupivacaine 5 mg.ml-1 with 5 microgram epinephrine as a 30 ml interpleural bolus, followed by a continuous infusion starting at a rate of 7 ml per hour and epidurally a bolus of 0.9% NaCl followed by a continuous infusion of 0.9% NaCl. The epidural group was given bupivacaine 3.75 mg.ml-1 with 5 microgram epinephrine as a 5 ml epidural bolus, followed by a continuous infusion starting at a rate of 5 ml per hour and interpleurally a bolus of 0.9% NaCl followed by a continuous infusion of 0.9% NaCl. The draining tubes were clamped during the injection of the interpleural bolus and 15 min afterwards. Adequacy of pain relief was evaluated with the Prins-Henry pain scale. Morphine requirement was registered, there was no difference between the groups in pain scores or need for additional morphine.

Pain management and spirometry following thoracotomy: a prospective, randomized study of four techniques

Forty-five patients who underwent anterolateral and posterolateral thoracotomy were studied to compare the relative efficacy of cryoanalgesia, epidural morphine, intrapleural analgesia, and intravenous morphine for relief of postoperative pain and prevention of deterioration in pulmonary function. Spirometry (FEV1, FVC) was performed preoperatively and postoperatively. Patients' pain was assessed using the 0 to 100 mm visual analog scale. Because intravenous morphine was used to supplement pain relief in the patients who received intrapleural analgesia and cryoanalgesia, total morphine use was compared to that administered to patients in the intravenous morphine group. Epidural morphine was found to offer better pain relief than the other treatment modalities. There were no differences in spirometric testing between the groups at any time during the study. Although the number of evaluable patients was insufficient to draw definitive conclusions, 12-week follow-up suggested a difference in the incidence of post-thoracotomy pain syndrome in patients who received cryoanalgesia. It is concluded that post-thoracotomy pain is best relieved with epidural morphine, compared to intrapleural analgesia, cryoanalgesia, and parenteral morphine. There was no change in the deterioration in spirometric tests after thoracotomy, nor was there any advantage offered by cryoanalgesia or intrapleural analgesia over intravenous morphine, with respect to pain relief.

Thoracic versus lumbar epidural fentanyl for postthoracotomy pain

Thirty patients were prospectively randomized to receive either thoracic or lumbar epidural fentanyl infusion for postthoracotomy pain. Epidural catheters were inserted, and placement was confirmed with local anesthetic testing before operation. General anesthesia consisted of nitrous oxide, oxygen, isoflurane, intravenous fentanyl citrate (5 micrograms/kg), and vecuronium bromide. Pain was measured by a visual analogue scale (0 = no pain to 10 = worst pain ever). Postoperatively, patients received epidural fentanyl in titrated doses every 15 minutes until the visual analogue scale score was less than 4 or until a maximum fentanyl dose of 150 micrograms by bolus and an infusion rate of 150 micrograms/h was reached. The visual analogue scale score of patients who received thoracic infusion decreased from 8.8 +/- 0.5 to 5.5 +/- 0.7 (p < or = 0.05) by 15 minutes and to 3.5 +/- 0.4 (p < or = 0.05) by 45 minutes. The corresponding values in the lumbar group were 8.8 +/- 0.6 to 7.8 +/- 0.7 at 15 minutes and 5.3 +/- 0.9 at 45 minutes (p < or = 0.05). The infusion rate needed to maintain a visual analogue scale score of less than 4 was lower in the thoracic group (1.55 +/- 0.13 micrograms.kg-1 x h-1) than in the lumbar group (2.06 +/- 0.19 microgram.kg-1 x h-1) during the first 4 hours after operation (p < or = 0.05). The epidural fentanyl infusion rates could be reduced at 4, 24, and 48 hours after operation without compromising pain relief. Four patients in the lumbar group required naloxone hydrochloride intravenously.(ABSTRACT TRUNCATED AT 250 WORDS)

Side effects during continuous epidural infusion of morphine and fentanyl

Respiratory effects, nausea, somnolence, and pruritus were compared during a 48-hr period of continuous epidural morphine (n = 34) and fentanyl (n = 32) infusion in 66 patients following elective total replacement of the hip or knee joint. Respiratory effects were assessed by PaCO2. Side effects were assessed by visual analogue scale and considered to be present when the score was above 30. Assessment was made at preoperative visits then 3, 6, 12, 24, 36, and 48 hr after the epidural injection. The bolus dose and subsequent infusion rate were 3,900 +/- 1,300 micrograms and 427 +/- 213 micrograms.hr-1 for morphine, and 85 +/- 46 micrograms and 56 +/- 27 micrograms.hr-1 for fentanyl. Pain relief was similar in both groups. In the morphine group, PaCO2 elevation and nausea occurred over a period of more than 12 hr (P less than 0.05). In the fentanyl group, there was no PaCO2 change, and nausea was confined to the first few hours. Nausea was more severe (P less than 0.01 at six hours and more frequent (24 hr cumulative incidence, 53 vs 28%, P less than 0.05) in the morphine group. Somnolence was prominent within several hours in two-thirds of patients in both groups. Somnolence continued to decline thereafter in the morphine group, but it was demonstrable in approximately half of the patients throughout the second day in the fentanyl group. The incidence was higher in the fentanyl group at the 48th hr (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Thoracic epidural infusion for postoperative pain relief following abdominal aortic surgery: bupivacaine, fentanyl or a mixture of both?

Thirty patients who had undergone elective abdominal aortic surgery were studied in a prospective, randomised double-blind comparison of thoracic epidural 0.2% bupivacaine alone, thoracic epidural fentanyl alone and thoracic epidural 0.2% bupivacaine combined with fentanyl. Pain relief, pulmonary function, cardiovascular stability and side effects were assessed. Pain relief was excellent in the combined bupivacaine-fentanyl series, being significantly better than the other groups (p less than 0.05) during the entire study period and was not accompanied by hypotension. Forced expiratory parameters were reduced in all groups throughout the study to 50-60% of the pre-operative values, but there were no significant differences between groups. The incidence of side effects attributable to either epidural bupivacaine or fentanyl was low. This study supports the increasing use of epidural infusion analgesia for postoperative pain management after abdominal surgery.

Therapists and therapies for post-thoracotomy neuralgia

An unknown number of patients who undergo thoracic surgery develop post-thoracotomy neuralgia (PTN). Many seek a cure. As with other chronic, benign pain conditions, a variety of treatment modalities may be offered by different specialists. Results of therapy in terms of patient satisfaction are not known. A record of 73 patients with PTN was made. It has been used to measure the incidence, the natural and therapeutic history and the success of the management of PTN. Over 70% of the cases received three or more of the treatment modalities and regimens that have been reputed to be of value. More than 50% were referred to three different types of specialist. No patient claimed to have become free of symptoms as a result of treatment and a significant proportion, not clearly defined, implied that therapy was either more disabling than PTN or made it worse. Side effects of drugs were blamed for the former, and invasive treatments, aimed at nociceptive pathways, were incriminated in the latter. It is reasoned that about 5% of patients undergoing thoracic surgery may require resources for the management of PTN. No patient studied thought that conventional treatments had brought about a cure. Some treatments, known to be deleterious, remain extant. This information reflects and corroborates that from other studies which suggests that multidisciplinary approaches are more appropriate for chronic benign pain conditions than management by isolated physicians using specific therapies.

Pain following thoracotomy. A randomised, double-blind comparison of lumbar versus thoracic epidural fentanyl

Fifty-eight patients scheduled for elective thoracotomy were randomly allocated to receive fentanyl by either the thoracic or the lumbar epidural route for postoperative analgesia. The infusion rate was adjusted to optimise analgesia. Dose adjustment, pain assessment and the incidence of side effects were monitored by a blinded observer at set times over the 24 hour study period. Similar pain scores were obtained in both groups at all assessment times. In addition, there was no significant difference in dose requirements or incidence of side effects between the two groups. There appears little justification for the use of the generally less familiar, and potentially more dangerous, thoracic approach when fentanyl alone is infused into the epidural space following thoracotomy.

Continuous thoracic epidural fentanyl for post-thoracotomy pain relief: with or without bupivacaine?

Twenty-five ASA 1 or 2 patients undergoing thoracotomy were entered into a prospective, randomised, double-blind study comparing thoracic epidural fentanyl alone and thoracic epidural fentanyl combined with 0.2% bupivacaine. Pain relief, pulmonary function and cardiovascular stability were assessed. Pain relief was superior in the bupivacaine series (p less than 0.05) during the first day after operation and this was accompanied by better oxygenation (p less than 0.05); the difference did not persist into the second day. Forced expiratory variables were reduced in both series to 50-60% of the values before operation throughout the study (p less than 0.05) and differences did not occur between the groups. The incidence of side effects attributable to epidural fentanyl was high, but hypotension did not occur. Small doses of bupivacaine administered together with fentanyl into the thoracic epidural space improve analgesia without causing hypotension.

Postoperative pain management and respiratory depression after thoracotomy: a comparison of intramuscular piritramide and intravenous patient-controlled analgesia using fentanyl or buprenorphine

STUDY OBJECTIVE

To compare the analgesic efficacy of fentanyl, buprenorphine, and piritramide and to define the respiratory risk during conventional postoperative pain management and patient-controlled analgesia (PCA).

DESIGN

Randomized, single-blind study.

SETTING

Department of anesthesiology of an urban hospital.

PATIENTS

Sixty patients (ASA) physical status II and III) recovering from unilateral thoracotomy performed under standardized general anesthesia including intercostal blockade.

INTERVENTIONS

Patients were treated with intramuscular (IM) piritramide (7.5 to 15 mg as needed) or intravenous (IV) PCA with fentanyl (demand dose 34 micrograms) or buprenorphine (demand dose 80 micrograms) during the early postoperative period, using the On-Demand Analgesia Computer (ODAC, Janssen Scientific Instruments, Beerse, Belgium).

MEASUREMENTS AND MAIN RESULTS

The mean postoperative observation period was 24 to 25 hours. During this time, patients requested 55.8 +/- 23.2 mg of piritramide, 1.04 +/- 0.54 mg of fentanyl, or 1.81 +/- 0.78 mg of buprenorphine. Analgesia in all groups was judged mostly good to excellent, with a preference for PCA. Side effects were only of minor intensity in all groups; euphoria or dysphoria occurred only with buprenorphine. Two patients using PCA and five patients having IM analgesia developed short periods of respiratory depression (respiratory rate less than or equal to 8 breaths/minute and/or oxygen (O2) desaturation less than or equal to 90%), which promptly responded to commands to breathe deeply. Respiration rates did not differ, and frequent arterial blood sampling showed normal mean partial pressures of oxygen (PO2) and carbon dioxide (PCO2) and arterial oxygen saturation (SaO2) in all subgroups.

CONCLUSIONS

Opioid-induced respiratory depression occurred infrequently during postoperative pain management whether by conventional means or using PCA, even though high doses of opioid analgesics were required intermittently for adequate postoperative pain relief by either technique.

Continuous epidural hydromorphone for postthoracotomy pain relief

Forty-four patients were treated with a continuous infusion of lumbar epidural hydromorphone (0.05%) after thoracic operations. Postoperatively, visual analog pain scores were obtained. On postoperative day 1 and 2, more than 90% of the patients experienced either no pain (visual analog pain scale = 0) or mild pain (visual analog pain score = 1 to 3) at rest. The incidence of side effects (hypoventilation, pruritus, and nausea) was less than reported with other epidurally administered opioids. Continuous infusion of lumbar epidural hydromorphone produced safe, predictable analgesia after thoracotomy.

Lumbar epidural fentanyl infusions for post-thoracotomy patients: analgesic, respiratory, and pharmacokinetic effects

Ten patients undergoing a thoracotomy were studied for 24 hours postoperatively to determine the effects of a continuous lumbar epidural fentanyl infusion on postoperative pain, arterial blood gases (ABG), respiratory pattern (respiratory inductive plethysmography, RIP), and fentanyl plasma concentration (CONC). Patients served as their own controls because RIP and ABG data were obtained the night prior to surgery during sleep. Epidural fentanyl was administered as a bolus of 1.5 micrograms/kg followed by an infusion of 1.0 micrograms/kg/h started 1 hour after induction. Insufficient analgesia was treated with a bolus of 0.5 micrograms/kg and an infusion increase of 0.25 micrograms/kg/h. Postoperative assessment included RIP, ABG, CONC, and visual analog pain score (PS). The average infusion rate postoperatively was 1.47 +/- 0.08 micrograms/kg/h (114.3 +/- 8.3 micrograms/h). A mean PS of 2.1 +/- 0.3 was achieved; however, there was a delay in attaining this. There was no significant incidence postoperatively of apnea or slow respiratory rate. A significant but clinically insubstantial increase in PaCO2 and decrease in pH occurred. A steady state CONC of approximately 2.0 ng/mL was reached after 9 hours. The PS correlated with CONC in half the patients (0.60 less than r less than 0.86), indicating a systemic component may have contributed to the analgesic effect.