Comparison Between Two Intraoperative Intravenous Loading Doses of Paracetamol on Pain After Minor Hand Surgery: Two Grams Versus One Gram

Modelling Tools to Characterize Acetaminophen Pharmacokinetics in the Pregnant Population

This review describes acetaminophen pharmacokinetics (PK) throughout pregnancy, as analyzed by three methods (non-compartmental analyses (NCA), population PK, and physiologically based PK (PBPK) modelling). Eighteen studies using NCA were reported in the scientific literature. These studies reported an increase in the volume of distribution (3.5-60.7%) and an increase in the clearance (36.8-84.4%) of acetaminophen in pregnant women compared to non-pregnant women. Only two studies using population PK modelling as a technique were available in the literature. The largest difference in acetaminophen clearance (203%) was observed in women at delivery compared to non-pregnant women. One study using the PBPK technique was found in the literature. This study focused on the formation of metabolites, and the toxic metabolite N-acetyl-p-benzoquinone imine was the highest in the first trimester, followed by the second and third trimester, compared with non-pregnant women. In conclusion, this review gave an overview on acetaminophen PK changes in pregnancy. Also, knowledge gaps, such as fetal and placenta PK parameters, have been identified, which should be explored further before dosing adjustments can be suggested on an evidence-based basis.

Enhanced recovery and accelerated discharge after endoscopic transsphenoidal pituitary surgery: safety, patient feedback, and cost implications

BACKGROUND

Enhanced recovery after surgery (ERAS) is a constant motivation. There is growing evidence that an endoscopic (rather than microscopic) transsphenoidal approach to pituitary tumours can play a role, facilitating faster recovery and a commensurate reduction in length of stay (LOS). Reducing LOS is beneficial to both patients and healthcare systems. We sought to assess the safety, patient feedback, and resource implications of adopting an enhanced recovery and accelerated discharge policy for elective pituitary surgery.

METHODS

We retrospectively assessed two consecutive cohorts of patients undergoing elective surgery for pituitary adenoma in a single UK centre between July 2016 and November 2019. The pre-ERAS cohort included 52 sequential patients operated prior to protocol change. The ERAS cohort included 55 sequential patients operated after a protocol change. Patient demographic data, tumour characteristics, intra- and post-operative CSF leak, the rate and cause of readmission (within 30 days), and the mean and median LOS were recorded. Patient feedback was collected from a subset of patients (n = 23) in the ERAS group.

RESULTS

The two cohorts were well-matched with respect to their demographic, pathological, and operative characteristics. The rates of readmission within 30 days of discharge were similar between the two groups (8% pre-ERAS cohort, 9% ERAS cohort, p = 0.75). In the pre-ERAS cohort, the mean LOS was 4.5 days and median LOS was 3 days. This compares with significant reduction in LOS for the ERAS group: mean of 1.7 days and median of 1 day (p < 0.05). Thirty-nine of 55 patients in the ERAS group were discharged on post-operative day 1. Patient feedback was very positive in the ERAS group (mean patient satisfaction score of 9.7/10 using a Likert scale).

CONCLUSIONS

An enhanced recovery protocol after elective endoscopic pituitary surgery is safe, reduces length of stay, and is associated with high patient satisfaction.

Rehabilitation following carpal tunnel release

BACKGROUND

Various rehabilitation treatments may be offered following carpal tunnel syndrome (CTS) surgery. The effectiveness of these interventions remains unclear. This is the first update of a review first published in 2013.

OBJECTIVES

To review the effectiveness and safety of rehabilitation interventions following CTS surgery compared with no treatment, placebo, or another intervention.

SEARCH METHODS

On 29 September 2015, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL Plus, AMED, LILACS, and PsycINFO. We also searched PEDro (3 December 2015) and clinical trials registers (3 December 2015).

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials that compared any postoperative rehabilitation intervention with either no intervention, placebo, or another postoperative rehabilitation intervention in individuals who had undergone CTS surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data, assessed risk of bias, and assessed the quality of the body of evidence for primary outcomes using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach according to standard Cochrane methodology.

MAIN RESULTS

In this review we included 22 trials with a total of 1521 participants. Two of the trials were newly identified at this update. We studied different rehabilitation treatments including immobilisation using a wrist orthosis, dressings, exercise, controlled cold therapy, ice therapy, multi-modal hand rehabilitation, laser therapy, electrical modalities, scar desensitisation, and arnica. Three trials compared a rehabilitation treatment to a placebo, four compared rehabilitation to a no treatment control, three compared rehabilitation to standard care, and 15 compared various rehabilitation treatments to one another.Overall, the included studies were very low in quality. Thirteen trials explicitly reported random sequence generation; of these, five adequately concealed the allocation sequence. Four trials achieved blinding of both participants and outcome assessors. Five were at high risk of bias from incompleteness of outcome data at one or more time intervals, and eight had high risk of selective reporting bias.These trials were heterogeneous in terms of treatments provided, duration of interventions, the nature and timing of outcomes measured, and setting. Therefore, we were not able to pool results across trials.Four trials reported our primary outcome, change in self reported functional ability at three months or more. Of these, three trials provided sufficient outcome data for inclusion in this review. One small high-quality trial studied a desensitisation programme compared with standard treatment and revealed no statistically significant functional benefit based on the Boston Carpal Tunnel Questionnaire (BCTQ) (mean difference (MD) -0.03, 95% confidence interval (CI) -0.39 to 0.33). One low-quality trial assessed participants six months post surgery using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and found no significant difference between a no formal therapy group and a group given a two-week course of multi-modal therapy commenced at five to seven days post surgery (MD 1.00, 95% CI -4.44 to 6.44). One very low-quality quasi-randomised trial found no statistically significant difference in function on the BCTQ at three months post surgery with early immobilisation (plaster wrist orthosis worn until suture removal) compared with a splint and late mobilisation (MD 0.39, 95% CI -0.45 to 1.23).Differences between treatments for secondary outcome measures (change in self reported functional ability measured at less than three months; change in CTS symptoms; change in CTS-related impairment measures; presence of iatrogenic symptoms from surgery; return to work or occupation; and change in neurophysiological parameters) were generally small and not statistically significant. Few studies reported adverse events.

AUTHORS' CONCLUSIONS

There is limited and, in general, low quality evidence for the benefit of the reviewed interventions. People who have undergone CTS surgery should be informed about the limited evidence of effectiveness of postoperative rehabilitation interventions. Until researchers provide results of more high-quality trials that assess the effectiveness and safety of various rehabilitation treatments, the decision to provide rehabilitation following CTS surgery should be based on the clinician's expertise, the patient's preferences and the context of the rehabilitation environment. It is important for researchers to identify patients who respond to a particular treatment and those who do not, and to undertake high-quality studies that evaluate the severity of iatrogenic symptoms from surgery, measure function and return-to-work rates, and control for confounding variables.

Perioperative nonopioid agents for pain control in spinal surgery

PURPOSE

Commonly used nonopioid analgesic agents that are incorporated into multimodal perioperative pain management protocols in spinal surgery are reviewed.

SUMMARY

Spinal procedures constitute perhaps some of most painful surgical interventions, as they often encompass extensive muscle dissection, tissue retraction, and surgical implants, as well as prolonged operative duration. Perioperative nonopioid analgesics frequently used in multimodal protocols include gabapentin, pregabalin, acetaminophen, dexamethasone, ketamine, and nonsteroidal antiinflammatory drugs (NSAIDs). There is evidence to suggest that gabapentin is safe and effective in reducing opioid consumption and pain scores at optimal doses of 600-900 mg orally administered preoperatively. Pregabalin 150-300 mg orally perioperatively has been shown to reduce both pain and narcotic consumption. Most reports concur that a single 1-g i.v. perioperative dose is safe in adults and that this dose has been shown to reduce pain and attenuate narcotic requirements. Dexamethasone's influence on postoperative pain has primarily been investigated for minor spinal procedures, with limited evidence for spinal fusions. Ketamine added to a patient-controlled analgesia regimen appears to be efficacious for 24 hours postoperatively when implemented for microdiskectomy and laminectomy procedures at doses of 1 mg/mL in a 1:1 mixture with morphine. For patients undergoing laminectomy or diskectomy, NSAIDs appear to be safe and effective in reducing pain scores and decreasing opioid consumption.

CONCLUSION

Preemptive analgesic therapy combining nonopioid agents with opioids may reduce narcotic consumption and improve patient satisfaction after spinal surgery. Such therapy should be considered for patients undergoing various spinal procedures in which postoperative pain control has been historically difficult to achieve.

Pharmacokinetics of paracetamol and its metabolites in women at delivery and post-partum

AIM

A recent report on intravenous (i.v.) paracetamol pharmacokinetics (PK) showed a higher total clearance in women at delivery compared with non-pregnant women. To describe the paracetamol metabolic and elimination routes involved in this increase in clearance, we performed a population PK analysis in women at delivery and post-partum in which the different pathways were considered.

METHODS

Population PK parameters using non-linear mixed effect modelling were estimated in a two-period PK study in women to whom i.v. paracetamol (2 g loading dose followed by 1 g every 6 h up to 24 h) was administered immediately following Caesarean delivery and in a subgroup of the same women to whom single 2 g i.v.loading dose was administered 10-15 weeks post-partum.

RESULTS

Population PK analysis was performed based on 255 plasma and 71 urine samples collected in 39 women at delivery and in eight of these 39 women 12 weeks post-partum. Total clearance was higher in women at delivery compared with 12th post-partum week (21.1 vs. 11.7 l h⁻¹) due to higher clearances to paracetamol glucuronide (11.6 vs. 4.76 l h⁻¹), to oxidative metabolites (4.95 vs. 2.77 l h⁻¹) and of unchanged paracetamol (1.15 vs. 0.75 l h⁻¹). In contrast, there was no difference in clearance to paracetamol sulphate.

CONCLUSION

The increased total paracetamol clearance at delivery is caused by a disproportional increase in glucuronidation clearance and a proportional increase in clearance of unchanged paracetamol and in oxidation clearance, of which the latter may potentially limit further dose increase in this patient group.

Rehabilitation following carpal tunnel release

BACKGROUND

Various rehabilitation treatments may be offered following carpal tunnel syndrome (CTS) surgery. The effectiveness of these interventions remains unclear.

OBJECTIVES

To review the effectiveness of rehabilitation following CTS surgery compared with no treatment, placebo, or another intervention.

SEARCH METHODS

On 3 April 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register (3 April 2012), CENTRAL (2012, Issue 3), MEDLINE (January 1966 to March 2012), EMBASE (January 1980 to March 2012), CINAHL Plus (January 1937 to March 2012), AMED (January 1985 to April 2012), LILACS (January 1982 to March 2012), PsycINFO (January 1806 to March 2012), PEDRO (29 January 2013) and clinical trials registers (29 January 2013).

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials that compared any postoperative rehabilitation intervention with either no intervention, placebo or another postoperative rehabilitation intervention in individuals who had undergone CTS surgery.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion, extracted data and assessed the risk of bias according to standard Cochrane methodology.

MAIN RESULTS

In this review we included 20 trials with a total of 1445 participants. We studied different rehabilitation treatments including: immobilisation using a wrist orthosis, dressings, exercise, controlled cold therapy, ice therapy, multimodal hand rehabilitation, laser therapy, electrical modalities, scar desensitisation, and arnica. Three trials compared a rehabilitation treatment to a placebo comparison; three trials compared rehabilitation to a no treatment control; three trials compared rehabilitation to standard care; and 14 trials compared various rehabilitation treatments to one another.Overall, the included studies were very low in quality. Eleven trials explicitly reported random sequence generation and, of these, three adequately concealed the allocation sequence. Four trials achieved blinding of both participants and outcome assessors. Five studies were at high risk of bias from incompleteness of outcome data at one or more time intervals. Eight trials had a high risk of selective reporting bias.The trials were heterogenous in terms of the treatments provided, the duration of interventions, the nature and timing of outcomes measured and setting. Therefore, we were not able to pool results across trials.Four trials reported our primary outcome, change in self reported functional ability at three months or longer. Of these, three trials provided sufficient outcome data for inclusion in this review. One small high quality trial studied a desensitisation program compared to standard treatment and revealed no statistically significant functional benefit based on the Boston Carpal Tunnel Questionnaire (BCTQ) (MD -0.03; 95% CI -0.39 to 0.33). One moderate quality trial assessed participants six months post surgery using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and found no significant difference between a no formal therapy group and a two-week course of multimodal therapy commenced at five to seven days post surgery (MD 1.00; 95% CI -4.44 to 6.44). One very low quality quasi-randomised trial found no statistically significant difference in function on the BCTQ at three months post surgery with early immobilisation (plaster wrist orthosis worn until suture removal) compared with a splint and late mobilisation (MD 0.39; 95% CI -0.45 to 1.23).The differences between the treatments for the secondary outcome measures (change in self reported functional ability measured at less than three months; change in CTS symptoms; change in CTS-related impairment measures; presence of iatrogenic symptoms from surgery; return to work or occupation; and change in neurophysiological parameters) were generally small and not statistically significant. Few studies reported adverse events.

AUTHORS' CONCLUSIONS

There is limited and, in general, low quality evidence for the benefit of the reviewed interventions. People who have had CTS surgery should be informed about the limited evidence of the effectiveness of postoperative rehabilitation interventions. Until the results of more high quality trials that assess the effectiveness and safety of various rehabilitation treatments have been reported, the decision to provide rehabilitation following CTS surgery should be based on the clinician's expertise, the patient's preferences and the context of the rehabilitation environment. It is important for researchers to identify patients who respond to a certain treatment and those who do not, and to undertake high quality studies that evaluate the severity of iatrogenic symptoms from the surgery, measure function and return-to-work rates, and control for confounding variables.

Role of intravenous acetaminophen in postoperative pain management

SUMMARY The need to safely treat the postoperative pain of patients is apparent. Opioids, although effective, have multiple morbidities associated with their use. A multimodal approach to postoperative pain management can serve to minimize the undesirable effects of opioids. Intravenous acetaminophen (paracetamol) has recently become available in the USA where many practitioners are not familiar with this drug. This article reviews the history, pharmacology and clinical uses of intravenous acetaminophen in the treatment of perioperative pain.

Pharmacokinetics of a loading dose of intravenous paracetamol post caesarean delivery

BACKGROUND

The postpartum period affects drug disposition, but data of intravenous paracetamol loading dose pharmacokinetics immediately following caesarean delivery have not yet been reported.

METHODS

Immediately following caesarean delivery, women received a 2-g loading dose of intravenous paracetamol. Plasma samples were collected at 1, 2, 4 and 6 h. Individual pharmacokinetics were calculated assuming a linear one-compartment model with instantaneous input and first-order output. Data were reported using median and range.

RESULTS

Twenty-eight patients undergoing caesarean delivery were recruited (age 31.5 [20-42] years, weight 79 [57-110] kg, body surface area 1.9 [1.5-2.4]m(2)). Median paracetamol plasma concentrations after 1, 2, 4 and 6 h were 22.5, 15.25, 7.9, and 3.9 mg/L respectively. Paracetamol clearance was 20.3 (11.8-62.8) L/h or 10.9 (7-23.8)L/hm(2), distribution volume 58.3 (42.9-156) L or 0.72 (0.52-1.56) L/kg.

CONCLUSION

Pharmacokinetics of intravenous paracetamol have been estimated following caesarean delivery. Although limited to a loading dose shortly after surgery, the results are clinically relevant since this is the first description in this patient population. These data provide evidence on which to base further integrated pharmacokinetic/pharmacodynamic studies in peripartum analgesia.

Effectiveness of intravenous acetaminophen for pain management in orthopedic surgery patients: a systematic review

BACKGROUND

Fear of poor pain management has been listed by patients as a reason for delaying or refusing surgical procedures. Uncontrolled pain has been associated with increased time in the post anesthesia care unit, poor sleep, increased hospital length of stay and decreased patient satisfaction. Acetaminophen (paracetamol) has been used for more than a century to control pain and to treat fever in both adults and children. The intravenous formulation has been available in Europe for many years, but it has only recently become available in the United States.

REVIEW OBJECTIVE

The objective was to synthesize the best available evidence regarding the safety and efficacy of intravenous acetaminophen (paracetamol) for pain control after an orthopedic surgical procedure.

INCLUSION CRITERIA

The review considered patients 18 years of age and older who had received intravenous acetaminophen (paracetamol) for pain control after an orthopedic surgical procedure.This review considered as intervention the intravenous acetaminophen (paracetamol) for pain control after an orthopedic surgical procedure.This review considered the following outcome measures: pain intensity, pain relief, pain scores, use of rescue medication, adverse event reporting, and patient satisfaction scores.This review considered only randomized controlled trials.

SEARCH STRATEGY

The search strategy aimed to find both published and unpublished studies in English language from 2006 to 2011. Multiple databases were searched including MEDLINE, CINAHL, EMBASE, and EBSCO.

METHODOLOGICAL QUALITY

The studies were critically appraised using the standardized instruments provided by the Joanna Briggs Institute.

DATA COLLECTION

Data was extracted using standardised data extraction form provided by the Joanna Briggs Institute DATA SYNTHESIS: Due to the heterogeneous nature of the study methods meta-analysis was considered not appropriate. The results are presented in a narrative summary.

RESULTS

The use of intravenous acetaminophen (paracetamol) for the treatment of pain and fever is gaining increased acceptance across a wide variety of patients despite limited research. The systematic review to identify randomized control trials in orthopedic patients identified only two such studies. These studies were in vastly different patient groups and the results of which could not be combined for meta-analysis.

CONCLUSIONS

The results of this review indicate that intravenous acetaminophen (paracetamol) has been used during and following a variety of orthopedic surgical procedures with moderate improvement in post procedural pain, but did not substantially change the need for rescue medications.

IMPLICATIONS FOR PRACTICE

The studies included in this review provide insufficient evidence to support the routine use of intravenous acetaminophen (paracetamol) for pain control following orthopedic surgical procedures.

IMPLICATIONS FOR RESEARCH

Further research is needed in a broader patient population. Measurements for interventions and outcomes need to be standardized in order to ensure proper comparison and application of results.