190
through pain). The addition of a 3 mg hydromorsubstantially improved pain control. Thus, we observed that an opioid suppository at a very low dose, which was used during a period of increased abdominal pressure, was far more effective than would be expected given the quantity of morphine administered by infusion. During the same period, an increase in the continuous morphine infusion to 40 mg/hr produced a minimal effect. These observations suggest that further investigation is warranted. Pharmacokinetic and pharmacodynamic (PK-PD) studies in the rat or other animals known to have a vertebral venous plexus may clarify the issue.4 Studies of analgesic efficacy in man should assess the relief produced by opioid suppositories with and without abdominal pressure and should be done, prefrably with concomitant measurements of blood and spinal fluid opioid concentrations. Theoretically, injection of an analgesic into the dorsal vein of the penis, with and without abdominal binders, could provide definitive PK-PD data. There are, of course, alternative explanations for the improved analgesia with rectal administration observed in our patients. For example, it is possible that the venous drainage from the rectum in these patients mostly bypassed the portal circulation, reducing “first pass” hepatic metabolism and increasing the systemic bioavailability of these drugs. Other explanations are possible. Studies are needed to identifjl the cause phone rectal suppository provided
Latenq as Predictor of PostsurgicalPain Intensity and Duration To the Editor: To date, a number of factors affecting postsurgical pain intensity have been identified such as personality traits,‘l* coping ability,3 P-endorphin levelsp and so on (some of which have predictive value), but it would be useful to handle an early and easy index of the incoming pain. Theoretically, to be reliable, this index should be extrapolated from the results collected in a clinical setting free of the limitation of analgesics intake. The thoracic surge.ons of Bologna University have provided us with the opportunity of studying the latency, duration, and intensity of postthoracotomy pain in a setting in which the
.-_-~ll--Vol.7.Nn.4 May 1992
L&m
of improved analgesia and then studies should include evaluation of the Batson’s plexus hypothesis. If analgesics delivered by this method do produce a high concentration at a spinal cord level, this procedure may be of significant benefit to patients with lower extremity and lumbar pain, and may, in theory, provide an alternative to catheter implantation for epidurally-delivered medications. Giibcrt R. Gonzales, MD and
Richard Payne, MD Department of Neurology University of Cincinnati Cincinnati, Ohio
References 1.Batson OV. The
function of the vertebral veins and their role in the spread of metastases. Ann Surg 1940;112:138-149.
2. Epstein HM, Linde W, Clampton AR, Chic IS, Schcnhoff JE. The vertebral venous plexus as a major cerebral outflow tract. venous Anesthesiology 1970;32:332-337. 3. Eckcnhoff JE. The physiologic significance vertebral venous plexus. Surg Gynecol 1970;131:72-76.
of the Obstet
4. Kato A, Ushio Y, Hayakawa T, Yamada K, Ikeda H, Mogami H. Circulatory disturbance of the spinal cord with epidural neoplasm in rats. J Neurosurg 1985;63:260-265.
analgesics consumption was minimized, the clinical staff having adopted, for many years, a psychological approach to influence patients’ cognitive orientation and tberefore the pain they experience.5 The subjects consisted of a series of 126 patients (36 females, 90 males; age 55 f 13 years: range, 18-78 years), thoracic surgery candidates for benign (IV= 27) and for malignant (Jv= 99) lesions. The patients were submitted to a standardized preanesthesia (opiate premedication) and anesthesia. We defined pain latency as the time that elapsed between awakening from anesthesia and onset of pain. Pain intensity was recorded daily at 4 p.m. on a visual analogue scale (VAS, O-10) indicating the point of maximum pain intensity experienced during the preceding 24 hours. Pain duration was established as the total number of days the patients experienced pain. There was a large variability
vol. 7Jvo. 4 n/ray 1992
in the pain parameters recorded between individuals: the maximal pain intensity had a mean value of 7.61 (l-lo), the median latency was 3.5 hr (30 mm-144 hr), and the median pain duration was 7.1 days (l-42 days). The values regarding intensity and duration are in agreement with other results in postthoracotomy patient& already published, whereas data on latency have not been previously described. The quantitative relations between latency and both intensity and duration have been studied, and the following functions were tested to determine the best fit: linear, multiplicative, exponential, and reciprocal. Pearson regression analysis showed latency to be negatively correlated with intensity, and the best fit was represented by a linear function: Y = -0.27X + 9.25 (3 = 31.3, P < 0.001). Latency was also negatively correlated with duration, and the best fit was represented by a reciprocal function: 1 /Y = 0.02x+ 0.12 (12 = 17.3, PC 0.001).
To date, the preanesthesia and anesthesia procedures are the only factors proved to affect the latency of postsurgical pain7 &cause the premeditation and anesthesia protocol adopted in our department were preceded and furthermore correspond to the most common procedures employed, it is suggested that the latency parameter could be used as an easily obtainable predictor of the impending pain experience. Valeria Bachiocco, MD Istituto di Ancstcsia c Rianimazione Univcrsita di Bologna Italy
Le&rs
191
Roman0 Bragaglia, MD Istituto de Clinica Chirurgica II Universita di Bologna Italy and Giancarlo Carli, PhD Istituto di Fisiologia Umana Universita di Sierra Italy
1. Tanzer P, Melzack R, Jeans ME. Influence of psychological factors on postoperative pain, mood and analgesic requirements. Pain 1986;24:33 l-342. 2. Bachiocco V, Morselli Labate AM, Rusticali AG, Bragaglia R, Mastrolilli M, Carli G. Intensity, latency and duration of postthoracotomy pain: relationships to personality. Funct Neurol 1990;5:321-332. 3. Turner AJ, Roman0 h(J. Cognitive-behavioral therapy. Im Bonica JJ, ed. The management of pain. Philadelphia: Ica and Febigcr, 1990: 17 1 l-l 72 1. 4. Tamsen A, Sakurada T, Wahlstrom A, Terenius L, Hartvig P. Postoperative demand for analgesics in relation to individual levels of endorpbins and substance Pin cerebrospinal fluid. Pain 1982;13:171-183. 5. Abbey-Smith R Pain relief after thoracotomy. Lancet 1976;1:815. 6. El-Baz NMI, Penficld Faber L, Jensik RG. Continuous epidural infusion of morphine for treatment of pain after thoracic surgery: a new technique. Anaesth Analg 1084;63:757-764. 7. McQuay HG, Carroll D, Moore RA. Postoperative orthopacdic pain: the effect of opiate premeditation and local anaesthctic blocks. Pain 1988;33:291-295.
through pain). The addition of a 3 mg hydromorsubstantially improved pain control. Thus, we observed that an opioid suppository at a very low dose, which was used during a period of increased abdominal pressure, was far more effective than would be expected given the quantity of morphine administered by infusion. During the same period, an increase in the continuous morphine infusion to 40 mg/hr produced a minimal effect. These observations suggest that further investigation is warranted. Pharmacokinetic and pharmacodynamic (PK-PD) studies in the rat or other animals known to have a vertebral venous plexus may clarify the issue.4 Studies of analgesic efficacy in man should assess the relief produced by opioid suppositories with and without abdominal pressure and should be done, prefrably with concomitant measurements of blood and spinal fluid opioid concentrations. Theoretically, injection of an analgesic into the dorsal vein of the penis, with and without abdominal binders, could provide definitive PK-PD data. There are, of course, alternative explanations for the improved analgesia with rectal administration observed in our patients. For example, it is possible that the venous drainage from the rectum in these patients mostly bypassed the portal circulation, reducing “first pass” hepatic metabolism and increasing the systemic bioavailability of these drugs. Other explanations are possible. Studies are needed to identifjl the cause phone rectal suppository provided
Latenq as Predictor of PostsurgicalPain Intensity and Duration To the Editor: To date, a number of factors affecting postsurgical pain intensity have been identified such as personality traits,‘l* coping ability,3 P-endorphin levelsp and so on (some of which have predictive value), but it would be useful to handle an early and easy index of the incoming pain. Theoretically, to be reliable, this index should be extrapolated from the results collected in a clinical setting free of the limitation of analgesics intake. The thoracic surge.ons of Bologna University have provided us with the opportunity of studying the latency, duration, and intensity of postthoracotomy pain in a setting in which the
.-_-~ll--Vol.7.Nn.4 May 1992
L&m
of improved analgesia and then studies should include evaluation of the Batson’s plexus hypothesis. If analgesics delivered by this method do produce a high concentration at a spinal cord level, this procedure may be of significant benefit to patients with lower extremity and lumbar pain, and may, in theory, provide an alternative to catheter implantation for epidurally-delivered medications. Giibcrt R. Gonzales, MD and
Richard Payne, MD Department of Neurology University of Cincinnati Cincinnati, Ohio
References 1.Batson OV. The
function of the vertebral veins and their role in the spread of metastases. Ann Surg 1940;112:138-149.
2. Epstein HM, Linde W, Clampton AR, Chic IS, Schcnhoff JE. The vertebral venous plexus as a major cerebral outflow tract. venous Anesthesiology 1970;32:332-337. 3. Eckcnhoff JE. The physiologic significance vertebral venous plexus. Surg Gynecol 1970;131:72-76.
of the Obstet
4. Kato A, Ushio Y, Hayakawa T, Yamada K, Ikeda H, Mogami H. Circulatory disturbance of the spinal cord with epidural neoplasm in rats. J Neurosurg 1985;63:260-265.
analgesics consumption was minimized, the clinical staff having adopted, for many years, a psychological approach to influence patients’ cognitive orientation and tberefore the pain they experience.5 The subjects consisted of a series of 126 patients (36 females, 90 males; age 55 f 13 years: range, 18-78 years), thoracic surgery candidates for benign (IV= 27) and for malignant (Jv= 99) lesions. The patients were submitted to a standardized preanesthesia (opiate premedication) and anesthesia. We defined pain latency as the time that elapsed between awakening from anesthesia and onset of pain. Pain intensity was recorded daily at 4 p.m. on a visual analogue scale (VAS, O-10) indicating the point of maximum pain intensity experienced during the preceding 24 hours. Pain duration was established as the total number of days the patients experienced pain. There was a large variability
vol. 7Jvo. 4 n/ray 1992
in the pain parameters recorded between individuals: the maximal pain intensity had a mean value of 7.61 (l-lo), the median latency was 3.5 hr (30 mm-144 hr), and the median pain duration was 7.1 days (l-42 days). The values regarding intensity and duration are in agreement with other results in postthoracotomy patient& already published, whereas data on latency have not been previously described. The quantitative relations between latency and both intensity and duration have been studied, and the following functions were tested to determine the best fit: linear, multiplicative, exponential, and reciprocal. Pearson regression analysis showed latency to be negatively correlated with intensity, and the best fit was represented by a linear function: Y = -0.27X + 9.25 (3 = 31.3, P < 0.001). Latency was also negatively correlated with duration, and the best fit was represented by a reciprocal function: 1 /Y = 0.02x+ 0.12 (12 = 17.3, PC 0.001).
To date, the preanesthesia and anesthesia procedures are the only factors proved to affect the latency of postsurgical pain7 &cause the premeditation and anesthesia protocol adopted in our department were preceded and furthermore correspond to the most common procedures employed, it is suggested that the latency parameter could be used as an easily obtainable predictor of the impending pain experience. Valeria Bachiocco, MD Istituto di Ancstcsia c Rianimazione Univcrsita di Bologna Italy
Le&rs
191
Roman0 Bragaglia, MD Istituto de Clinica Chirurgica II Universita di Bologna Italy and Giancarlo Carli, PhD Istituto di Fisiologia Umana Universita di Sierra Italy
1. Tanzer P, Melzack R, Jeans ME. Influence of psychological factors on postoperative pain, mood and analgesic requirements. Pain 1986;24:33 l-342. 2. Bachiocco V, Morselli Labate AM, Rusticali AG, Bragaglia R, Mastrolilli M, Carli G. Intensity, latency and duration of postthoracotomy pain: relationships to personality. Funct Neurol 1990;5:321-332. 3. Turner AJ, Roman0 h(J. Cognitive-behavioral therapy. Im Bonica JJ, ed. The management of pain. Philadelphia: Ica and Febigcr, 1990: 17 1 l-l 72 1. 4. Tamsen A, Sakurada T, Wahlstrom A, Terenius L, Hartvig P. Postoperative demand for analgesics in relation to individual levels of endorpbins and substance Pin cerebrospinal fluid. Pain 1982;13:171-183. 5. Abbey-Smith R Pain relief after thoracotomy. Lancet 1976;1:815. 6. El-Baz NMI, Penficld Faber L, Jensik RG. Continuous epidural infusion of morphine for treatment of pain after thoracic surgery: a new technique. Anaesth Analg 1084;63:757-764. 7. McQuay HG, Carroll D, Moore RA. Postoperative orthopacdic pain: the effect of opiate premeditation and local anaesthctic blocks. Pain 1988;33:291-295.
