Leiv Arne Rosseland

Assessment of pain

UNLABELLED Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on METHODS Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

Continuous Invasive Blood Pressure and Cardiac Output Monitoring during Cesarean Delivery A Randomized, Double-blind Comparison of Low-dose versus High-dose Spinal Anesthesia with Intravenous Phenylephrine or Placebo Infusion

Background: Prevention of hemodynamic instability during cesarean delivery during spinal anesthesia has been the aim of several studies. Noninvasive monitoring has been used in all previous studies. This is the first study in healthy pregnant women with continuous invasive recording of arterial blood pressure, cardiac output, and systemic vascular resistance. The aim of this randomized trial was to compare the effects of two different intrathecal doses of bupivacaine, with or without intravenous phenylephrine infusion, on cardiac output and systolic blood pressure. Methods: In this double-blinded study, 80 healthy women scheduled to undergo elective cesarean delivery were randomly assigned to one of four different groups receiving 7 mg spinal bupivacaine with or without a concomitant low-dose infusion of phenylephrine (0.25 &mgr;g · kg−1 · min−1) or 10 mg spinal bupivacaine with or without phenylephrine infusion. All patients had 4 &mgr;g sufentanil added to the spinal solution and had cohydration with 750 ml saline, 0.9%. Results: The low-dose spinal bupivacaine group with intravenous phenylephrine infusion was the most stable group regarding all hemodynamic variables. The authors found significant differences between this group and the group that was given the high dose of bupivacaine with intravenous placebo infusion regarding cardiac output (P = 0.005), systemic vascular resistance (P < 0.0001), and systolic blood pressure (P = 0.012). Conclusions: This study shows that low-dose bupivacaine (with sufentanil), combined with a low-dose infusion of phenylephrine and moderate cohydration, gives the best hemodynamic stability during spinal anesthesia for cesarean delivery.

Gender is a confounding factor in pain trials: women report more pain than men after arthroscopic surgery.

&NA; A gender difference in the incidence of acute pain may be a confounder in analgesic trials. We have tested the hypothesis that the incidence of acute pain after knee arthroscopic procedures is greater in women than men. We performed three RCTs on intra‐articular analgesics in which no postoperative analgesia was given until the need for such treatment was documented by scoring moderate‐to‐severe pain on a verbal rating scale (VRS 0–4; n=219), and a 0–100 mm visual analogue pain scale (VAS) within 2 h postoperatively. All trials were performed with an intra‐articular catheter technique. The design allowed us to study the natural course of pain after arthroscopic surgery until analgesia was required. Women reported more pain of at least moderate intensity than men (84 vs 57%; P<0.0001), indicating that being female is a risk factor for early postoperative pain (RR 1.47, 95% confidence interval from 1.23 to 1.74). The VAS score corresponding to moderate and severe pain is similar in men and women. Only short acting anaesthetics were given in order to minimise carry‐over effects. Since previous trials on arthroscopic analgesics neither measured baseline pain nor stratified for gender, a difference between treatment groups could result from an uneven distribution regarding these factors. Our findings have major implications for the interpretation of previously published trials on intra‐articular analgesia.

Detecting postoperative urinary retention with an ultrasound scanner

Background: Retention of urine is a common postoperative problem associated with risk of overdistention and permanent detrusor damage. Prevention of urinary retention by insertion of indwelling catheter may increase the risk of urinary infection. We have performed a reliability test of an ultrasound scanner, implemented in the postoperative monitoring equipment.

No evidence for analgesic effect of intra-articular morphine after knee arthroscopy: A qualitative systematic review

Background and Objectives: Intra-articular (IA) injection of morphine has been the subject of many randomized clinical trials (RCTs). Both negative and positive results have been obtained in trials with a preemptive design, and the question of efficacy remains unresolved. Recent RCTs on patients whose inclusion was delayed until a baseline pain of at least moderate intensity was documented have illuminated the pitfalls of IA analgesic trials. Previously published systematic reviews may have included flawed RCTs in the analyses. Methods: A systematic, qualitative review of RCTs on the analgesic efficacy of IA morphine after knee arthroscopic surgery. Results: Of the 67 screened RCTs, 46 RCTs (43 publications) of IA morphine were included. Thirty-six trials were placebo controlled. Twenty-three of these RCTs were of low scientific quality; randomization and blinding were not adequately described or the method used for statistical analysis of repeated measurements was unsound. Among the 13 RCTs with usable information, 4 of the positive outcomes may be explained by the uneven distribution of patients whose natural course was low postoperative pain intensity. Uneven sex distribution may be a confounding factor in one of these trials. Seven negative and 2 positive trials had reliable information. The only RCT with documented control over baseline pain intensity was negative. Most positive trials had small sample size. Publication bias favors the reporting and publication of positive trials more often than negative ones. Conclusions: There are few well-controlled RCTs on IA morphine, and the negative trials of higher quality counter the evidence from the numerous positive ones of lower quality. The quality of most published trials is poor, and performing meta-analysis on these data is not meaningful. Properly controlled trials, in which early postoperative pain intensity is documented, suggest that there is no added analgesic effect of IA morphine compared with saline alone.

Intra‐articular morphine for pain relief after knee arthroscopy

Background: Peripheral opioid analgesia is well documented. But the clinical usefulness of intra‐articular morphine after surgery is uncertain. The aim of the present study was to evaluate the analgesic effects of intra‐articular morphine after knee arthroscopy.

Effective pain relief from intra-articular saline with or without morphine 2 mg in patients with moderate-to-severe pain after knee arthroscopy: a randomized, double-blind controlled clinical study

Background: Intra‐articular (IA) morphine has given good and prolonged pain relief in some studies when given at the end of arthroscopic procedures in the knee joint. However, similar studies have not been able to document any local analgesic effect of morphine. A large number of the negative studies have not demonstrated any assay sensitivity. We have documented that around 40% of patients have only very mild or no pain after arthroscopic procedures in the knee joint. This obviously is a confounding factor, reducing assay sensitivity when all patients are included in IA morphine studies.

Changes in blood pressure during healthy pregnancy: a longitudinal cohort study.

Objective: To study longitudinally changes in blood pressure (BP) and heart rate (HR) during healthy pregnancies and to evaluate the influence of parity, pregestational overweight, and excessive weight gain. Methods: A prospective longitudinal cohort study of 57 healthy white women with singleton pregnancies. BP and HR were measured repeatedly at gestational age 14–16 weeks, 22–24 weeks, 30–32 weeks, 36 weeks, and 6 months postpartum using both an oscillometric measurement device (Dinamap) and finger arterial pressure (Finometer PRO). Results: SBP, DBP, and mean arterial pressure (MAP) reached a statistically significant trough at gestational age 22–24 weeks using both measurement devices. When compared with the nonpregnant measurement, SBP at gestational age 22–24 weeks was 6.2 mmHg [95% confidence interval (95% CI) 1.3–11.2] lower measured by Finometer and 7.2 mmHg (95% CI 4.2–10.1) lower measured by Dinamap. DBP and MAP were 8.9 mmHg (95% CI 4.6–13.2) and 9.8 mmHg (95% CI 5.3–14.2) lower measured by Finometer. Measured by Dinamap, DBP and MAP were 4.5 mmHg (95% CI 1.7–7.3) and 5.4 mmHg (95% CI 2.8–7.9) lower at gestational age 22–24 weeks when compared with the nonpregnant state. SBP was significantly higher in women with pregestational BMI at least 25 kg/m2 with both measurement devices (both P < 0.05). There were no differences in SBP, DBP, or MAP depending on parity or excessive weight gain. Conclusion: BP measured repeatedly by two different noninvasive devices during pregnancy and postpartum showed a statistically significant drop in mid-pregnancy, followed by a progressive increase until term.

Regional anaesthesia for a Caesarean section in women with cardiac disease: a prospective study.

Background We conducted a prospective observational survey of pregnant women with cardiac disease. The aim was to analyse and present the mode of delivery, outcome, and haemodynamic changes during a caesarean section under regional anaesthesia in women with cardiac disease.

Changes in blood pressure and cardiac output during cesarean delivery: the effects of oxytocin and carbetocin compared with placebo.

Background:Little is known about maternal hemodynamics after Cesarean delivery. Uterine contractions may increase cardiac output. Oxytocin is the first-line treatment for uterine atony, although the effects of the long-acting oxytocin analogue carbetocin are comparable with that of oxytocin. The authors analyzed the effects of i.v. oxytocin 5 U, carbetocin 100 µg, and placebo on hemodynamics, uterine tone, adverse events, and blood loss after Cesarean delivery. Methods:This was a randomized, double-blinded, placebo-controlled, parallel-group comparison of carbetocin and oxytocin after elective Cesarean delivery of singletons under spinal anesthesia (n = 76). Continuously measured invasive systolic arterial pressure was the primary outcome measure. Results:The mean systolic arterial pressure decrease was 28 mmHg (95% CI, 22–34) after oxytocin and 26 mmHg (95% CI, 20–31) after carbetocin. The decrease was greatest after 80 (95% CI, 71–89) and 63 s (95% CI, 55–72), respectively (P = 0.006). The differences were nearly undetectable after 2.5 min, although the effect of carbetocin was slightly greater than placebo (P < 0.001). The group differences in systolic arterial pressure decreased over 5 min and were gone at 1 h. Heart rate and cardiac output increased in all three groups. Stroke volume increased after oxytocin and carbetocin but was unchanged after placebo. Conclusions:The hemodynamic side effects of oxytocin 5 U and carbetocin 100 µg were comparable. The lack of an increase in stroke volume in the placebo group challenges the theory that uterine contraction causes autotransfusion of uterine blood, leading to an increase in preload.