A concept for the improvement of postoperative pain management

Many articles in the literature document the fact that postoperative pain therapy has not improved for decades despite new insights into pain physiology, the availability of powerful analgesics and the development of new techniques. This project was set up to develop practical, effective, safe, and easy to run acute pain therapy. METHODS. Postoperative pain management had to be optimized according to the facilities available today. Therefore, the legal background is presented first. Second, several medical and organizational principles were chosen to serve as a basis for the new organizational structure: Continuously monitoring the patient's pain during the whole stay in hospital, Introduction of a simple verbal 4-point pain score for determination and documentation of pain allowing the nurses to differentiate pain that should be treated or not, A simple sedation score, Use of "balanced analgesia" and "pre-emptive analgesia", Drug administration according to the needs of the patient, Partial transfer of the responsibility for pain treatment to nurses. Plans and algorithms were expanded to allow nurses and anaesthesiologists to reach the previously determined goals. RESULTS. In a small study including 107 patients, it was demonstrated that the quality of pain treatment improved significantly. Furthermore, patients, nurses and physicians are much more content with the new pain treatment regimen. DISCUSSION. The difficulties in realizing such a concept are described. The importance of thorough teaching is underlined in a nurse-based system. However, it is not yet clear whether this pain treatment has resulted in reduced morbidity, reduced mortality and a shortened hospital stay of the patients.     

Cultural effect on postoperative pain

OBJECTIVE: To investigate whether the S + G2/M fraction (proliferative index) is a prognostic determinant in breast cancers classified as Auer IV. STUDY DESIGN: Prognostic evaluation of Auer IV DNA histograms with respect to the high versus low S + G2/M fraction, obtained by image cytometry on consecutive breast cancer imprint preparations. RESULTS: When studying recurrence-free survival (n = 136), the prognostic value of S + G2/M was found to vary with time: it was negligible before the median time to relapse (1.5 years) but thereafter statistically significant, in both univariate and multivariate analysis. The same pattern was found when overall survival was used as the end point; the effect was delayed to about the median time until death (three years). Tumors with a low S + G2/M fraction were smaller and more often estrogen receptor- and progesterone receptor-positive than those with a high S + G2/M fraction. CONCLUSION: According to ICM-DNA values corresponding to the S + G2/M region, patients with breast cancers classified as Auer IV can be divided into subgroups with different tumor characteristics and prognoses.     

Preoperative assessment and prediction of postoperative results in an artificial arterial network using computer simulation

A computer model has been developed that can be used to describe the human arterial system mathematically. It simulates the complex relationship of morphology and hydraulics in the vessel network. After entering patient data into a standard vessel model, the mean flow velocity, the flow direction, and the blood pressure at each specified point of the flow network can be calculated. The vessel picture can be altered and modified with the help of a graphic editor. Localized or diffuse stenoses, bypasses with simple or multiple anastomoses, end-to-end anastomoses, end-to-side anastomoses, etc., can be studied in terms of the hydraulic effects on the local situation or on the entire vessel system. Experimental results of ultrasonic mean flow data in vessel systems of leg and cerebral arteries of patients are compared with calculated values. The predicted and measured flow velocities show a mean difference of about 10% indicating that such a computer model may be successfully used in the optimal planning of bypass operations.     

A pain education program for chronic cancer pain patients: follow-up results from a randomized controlled trial

The membrane bound metalloprotease aminopeptidase N (APN, CD13, EC 3.4.11.2) is a well established marker of normal and malignant cells of the myelo-monocytic lineage. It is also expressed by leukaemic blasts of a small group of patients suffering from acute or chronic lymphoid leukaemia. Recently, the expression of the APN gene in T cell lines as well as the induction of APN gene and surface expression in human peripheral T cells by mitogenic activation have been demonstrated. Here, by means of cytofluorimetric analysis evidence is provided, that the induction of APN surface expression is partially resistent to the action of the inhibitors of protein biosynthesis, puromycin and cycloheximide, and is not prevented by tunicamycin, an inhibitor of glycosylation. These data suggest that the rapid mitogen-induced surface expression of APN, detectable 20 hours after stimulation is dominated by mechanisms not dependent on de novo protein biosynthesis or glycosylation. As shown by simultaneous analyses, the inhibitors used did also differently modify the induction of surface expression of other inducible glycosylated leukocyte surface antigens, namely CD25, CD69 and CD95.     

Psychosocial predictors of children's postoperative pain

The purpose of this study was to investigate the influence of psychosocial variables in the prediction of children's pain intensity following surgery. Forty-two children, ages 7 to 17 years (M = 12.26, SD = 3.06), completed an interview 1 week prior to surgery assessing anticipatory distress related to their forthcoming surgery and history of coping strategy use. Following surgery, children reported the intensity of their pain using visual analog scales. Findings demonstrated that the majority of children experienced moderate to severe postoperative pain. Hierarchical multiple regression analyses revealed that psychosocial variables added to the prediction of children's postoperative pain after controlling for the influence of surgery-related and demographic variables. These findings lend initial support for the inclusion of psychosocial assessment measures (e.g., anticipatory surgery distress) in the preoperative assessment of pediatric patients who may be at risk for excessive postsurgical pain.     

How is postoperative pain evaluated?

The assessment of postoperative pain and analgesic efficacy is essential as pain levels and morphine requirements are not predictable. Self-assessment with unidimensional methods (such as the visual analogue pain scale, the numerical rating scale and the verbal rating scale) is the rule for adults and children more than 5 years of age. The former is a validated method and the most accurate and reproducible scale. Assessment of pain is difficult in children less than 5 years old. Only the scales for hetero-assessment with behavioural assessment (CHEOPS and OPS) are used. Finally, morphine consumption with PCA is also an indirect pain assessment method. Postoperative pain should be assessed several times a day in every patient, starting in the recovery room and prolonged during hospital stay. Pain should be measured at rest and in dynamic conditions by the medical and paramedical team.     

Measurement and assessment of postoperative pain: a short review

How to measure pain is a great challenge to those who desire to control adequately such a complex experience. Standardized instruments that take into consideration the patient's own account, have been developed in order to make such a task easier. In this article we carry out a revision of the instruments used mostly for measuring postoperative pain, and we point out some of the advantages and disadvantages. We emphasize the need for specific research focusing on the measurement of surgical pain, taking into consideration the multiple dimensions of a painful experience.     

The impact of postoperative pain on the development of postoperative delirium

We performed a prospective observational study to examine the role of postoperative pain and its treatment on the development of postoperative delirium. Pain was measured in direct patient interviews using a visual analog scale (VAS) and was assessed for pain at rest, pain with movement, and maximal pain over the previous 24 h. Postoperative delirium was diagnosed during these interviews by using the confusion assessment method (CAM) and/or by using data from the medical record and the hospital's nursing intensity index. The method of postoperative analgesia, type of opioid, and cumulative opioid dose were also recorded. After controlling for known preoperative risk factors for delirium (age, alcohol abuse, cognitive function, physical function, serum chemistries, and type of surgery), higher pain scores at rest was associated with an increased risk of delirium over the first 3 postoperative days (adjusted risk ratio 1.20, P = 0.04). Pain with movement and maximal pain were not associated with delirium. Method of postoperative analgesia, type of opioid, and cumulative opioid dose were not associated with an increased risk of delirium. We conclude that more effective control of postoperative pain reduces the incidence of postoperative delirium. Implications: We performed daily interviews in a large population of patients undergoing noncardiac surgery to measure their level of pain and development of delirium. We found an association between higher pain levels at rest and the development of delirium. Our results suggest that better control of postoperative pain may reduce this serious complication.     

Safety assessment of postoperative pain management by an acute pain service

The purpose of this study was to evaluate the synthetic retinoids isotretinoin and etretinate to treat dogs with intracutaneous cornifying epitheliomas (ICE), other benign skin neoplasias, and cutaneous lymphoma. Twenty-four dogs were used. All tumors were diagnosed by histologic examination. Ten dogs with multiple (at least 5) benign skin tumors (7 with ICE, 1 each with inverted papillomas, sebaceous adenomas and epidermal cysts) were treated with isotretinoin (n = 7) and/or etretinate (n = 5). Twelve dogs with cutaneous lymphoma were treated with isotretinoin, and 2 dogs with cutaneous lymphoma were initially treated with etretinate. Successful treatment with isotretinoin was achieved in 1 dog with ICE, 1 with inverted papillomas, and 1 with epidermal cysts. Partial improvement with isotretinoin was seen in 2 dogs with ICE. Successful treatment was achieved with etretinate in 4 dogs with ICE (Norwegian Elkhound was the predominant breed with ICE). Remission was achieved in 6 of the 14 dogs with cutaneous lymphoma. Adverse effects developed in 7 of the 24 dogs, so treatment was stopped in 2 dogs.     

Control of postoperative pain with intrapleural analgesia

INTRODUCTION: Personal experience in the treatment of postoperative pain using intrapleural analgesia applied on 50 patients chosen at random in a group of 90 after thoracotomy is reported. METHODS: At the end of operation a peridural catheter for continuative infusion was applied in the paravertebral socket by direct transfixion of chest wall. A local anaesthetic has been given (75 mg of bupivacaine 0.50%) through the catheter at 8 hours interval for three times at the most. The degree of analgesia has been valued immediately before and after medicine administration and during the 8 hours interval by recording the cardiocirculatory and haemogasanalytical parameters. The measurement of pain intensity has been achieved by visual analogous just an hour after operation and subsequently every 4 hours during the first post operative day and every 8 hours during the following days. RESULTS: Most of the examined patients (90%), reported a remarkable attenuation of pain, valued by achromatic grey test after 4 hours since the first giving. The catheter has always been removed during the 8th postoperative day and it did not cause intrapleural complications. The method used warrants a good level of analgesia, improving the respiratory per-formance and giving a rapid mobilization, essential items in the reduction of immediate post operative complications. CONCLUSIONS: The results confirm the validity of this treatment in the pain control of thoracothomized patients with a positive answer in 45 out of 50 examined patients without remarkable complications.     

Management of postoperative pain in surgical units

In order to improve the management of postoperative pain many publications insist on progressive changes in care organization. The following list outlines steps to be taken for implementation of these changes: 1) an initial analysis of management of post-operative pain allows awareness of reforms to be proposed; 2) participation of health teams in special training in order to use evaluation tools and collect data (use of analgesics, adverse effects); 3) establishing policies and procedures: recovery room, guidelines for analgesic use and adverse effects; 4) notifying patient about the various procedures to be used in postoperative period--discussion with the patient during the preoperative interview; 5) current use of standard patient-controlled analgesia (PCA) and locoregional analgesia; 6) use of combined techniques in order to achieve a balanced analgesia; 7) implementing a quality assurance programme which should include analgesic effectiveness, patient satisfaction and prevention of complications; and 8) planning of an Acute Pain Service based on a clinical nurse co-ordinator which offers highly effective forms of postsurgical analgesia.     

Total cavopulmonary anastomosis: selection criteria related to postoperative results

Cystitis cystica, a common urothelial pathology whose aetiology, morphology and clinical significance are poorly understood, affects the human urinary bladder and trigone in both sexes. We have studied the fine structure of urothelial cysts in 11 patients diagnosed cystoscopically as suffering from cystitis cystica. Several abnormal features were observed in the adjacent urothelium, including large intracellular vacuoles (4 patients), Brunn's nest (5), lymphocyte infiltration (10) and generally disorganised urothelial architecture (10). Squamous metaplasia was observed in one case. The wall of each cyst consisted of a 2-3 layered epithelium with either tall columnar or flattened cells lining the fluid-filled lumen. Both types of lining cell possessed short microvilli, while the columnar type also contained numerous membrane-bound, electron dense secretory granules in the apical cytoplasm. Rough endoplasmic reticulum, mitochondria and Golgi membranes were plentiful in the surface cells. Junctional complexes joined adjacent lining cells. The deeper cells contained relatively fewer organelles, while a basal lamina separated the cyst wall from the underlying connective tissue.     

Patient-controlled intranasal analgesia: a method for noninvasive postoperative pain management

Recently, a new device for patient-controlled intranasal analgesia (PCINA) was described, and a pilot study demonstrated promising results with respect to efficacy and patient satisfaction. The present study compares PCINA with intravenous (IV) patient-controlled analgesia (PCA). Fifty orthopedic patients were prospectively studied over an 8-h period on the first day after surgery. The patients were randomly allocated to PCINA group (n = 25) or to an IV PCA group (n = 25). Pain intensity was evaluated at 30-min intervals using a 101-point numerical rating scale. With respect to initial pain intensity, there was no significant intergroup difference. At the 30- to 480-min measurement points pain intensity in the PCINA group (P < 0.0001) and the IV PCA group (P < 0.0001) was significantly less as compared to the initial value. There was no significant intergroup difference in pain intensity. No patient had problems using the PCINA device. The present study demonstrates, that PCINA provides relief of postoperative pain as effectively as IV PCA.     

Effectiveness of documented assessment of postoperative pain

Documented assessment of pain does increase patient satisfaction in pain control and treatment but it must be carried out regularly and, more importantly, it must be acted upon. Patients who participate in documented assessment of pain postoperatively may find it easier to communicate their pain levels to the nurse, may feel more informed about their treatment and may be given analgesia more quickly than a control group. Nurses are aware of the importance of pain intensity assessment but do not always assess the effectiveness of the analgesia given. Each individual's perception of pain is unique and the desired amount of relief from pain is infinitely variable. Pain cannot be treated or controlled if it is not accurately assessed. Any information given before surgery decreases anxiety levels and therefore lessens the patient's perception of pain postoperatively, particularly when the information is related to how and where the patient may feel pain. The use of documented pain assessment combined with patient-controlled analgesia systems may be the key to effective postoperative pain control.     

Residual pneumoperitoneum: a cause of postoperative pain after laparoscopic cholecystectomy

After laparoscopic cholecystectomy, residual gas is inevitably retained in the peritoneal cavity. An active attempt is not always made to remove it. Using a double-blind prospective protocol in 40 healthy patients, we evaluated the effect of residual pneumoperitoneum on post-laparoscopic cholecystectomy pain intensity. On completion of surgery, prior to removal of the surgical instruments, the patients were randomly divided into two groups: in the active aspiration (AA) group an active attempt was made to remove as much gas as possible from the peritoneal cavity, while in the nonactive aspiration (NAA) group no such effort was made. Postoperative pain was assessed hourly over a 4-h period with a visual analog scale (VAS) and a patient-controlled analgesia (PCA) device. During the first postoperative hour, the NAA patients made significantly (P < 0.05) more demands (mean +/- SD) for morphine than those in the AA group (31.3 +/- 26.2 vs 15.3 +/- 15.7) and also received a borderline significantly (P = 0.056) larger dose (mean +/- SD) of PCA morphine (3.9 +/- 1.9 mg vs 2.7 +/- 1.3 mg). The VAS scores (mean +/- SD) over the 4-h study period were similar in both groups, being high during the first postoperative hour (AA = 5.1 +/- 2.1 vs NAA = 6.1 +/- 2.2) and then decreasing. We conclude that residual pneumoperitoneum is a contributing factor in the etiology of postoperative pain after laparoscopic cholecystectomy.     

A theory of conditioning: Inductive learning within rule-based default hierarchies.

We present a theory of classical conditioning based on a parallel, rule-based performance system integrated with mechanisms for inductive learning. Inferential heuristics are used to add new rules to the system in response to the relation between the system's predictions and environmental input. A major heuristic is based on "unusualness": Novel cues are favored as candidates to predict events that are important or unexpected. Rules have strength values that are revised on the basis of feedback. The performance system allows rules to operate in parallel, competing to control behavior and obtain reward for successful prediction of important events. Sets of rules can form default hierarchies: Exception rules censor useful but imperfect default rules, protecting them from loss of strength. The theory is implemented as a computer simulation, which is used to model a broad range of conditioning phenomena, including blocking and overshadowing, the impact of statistical predictability on conditioning, and conditioned inhibition. The theory accounts for a variety of phenomena that previous theories have not dealt with successfully. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The peripheral effect of fentanyl on postoperative pain

The clinical value of the analgesic effect of opioids administered peripherally (except for intraarticular administration) has not been clearly demonstrated. The aim of this study was to test the hypothesis that fentanyl, added to a local anesthetic for wound infiltration, can enhance postoperative analgesia via a peripheral mechanism. Patients with inguinal herniorrhaphy performed under spinal anesthesia were randomly assigned to one of two groups (n = 10 each). At the end of surgery, the wound was infiltrated with 10 mL of lidocaine 0.5% and fentanyl 0.001% (10 microg) in one group; in the other group, the wound was infiltrated with 10 mL of lidocaine 0.5% alone (and fentanyl 10 microg IM contralaterally). The following variables were determined in a double-blind manner: the duration of anesthesia (response to a von Frey filament), the duration of analgesia (time to mild postoperative pain), postoperative meperidine consumption, intensity visual analog scale of spontaneous and movement-associated pain 24 h after surgery, and wound pain threshold 24 h after surgery (pressure algometry). The addition of fentanyl for wound infiltration enhanced the duration of anesthesia (130+/-37 vs 197+/-27 min; P < 0.001) and decreased the intensity of spontaneous (50+/-17 vs 19+/-18 mm; P < 0.002) and movement-associated (56+/-15 vs 26+/-21 mm; P < 0.002) pain 24 h postoperatively. Differences between groups for other variables were not statistically significant. Fentanyl added to a local anesthetic for wound infiltration after spinal anesthesia can enhance postoperative analgesia by a peripheral mechanism. IMPLICATIONS: Fentanyl can enhance analgesia by a peripheral mechanism. Added to a local anesthetic for wound infiltration, it may be of benefit for the relief of postoperative pain.