The differential cancer growth associated with anaesthetics in a cancer xenograft model of mice: mechanisms and implications of postoperative cancer recurrence

Anaesthetics may modify colorectal cancer cell biology which potentially affects long-term survival. This study aims to compare propofol and sevoflurane regarding with the direct anaesthetic effects on cancer malignancy and the indirect effects on host immunity in a cancer xenograft mode of mice. Cultured colon cancer cell (Caco-2) was injected subcutaneously to nude mice (day 1). Mice were exposed to either 1.5% sevoflurane for 1.5 h or propofol (20 μg g-1; ip injection) with or without 4 μg g-1 lipopolysaccharide (LPS; ip) from days 15 to 17, compared with those without anaesthetic exposure as controls. The clinical endpoints including tumour volumes over 70 mm3 were closely monitored up to day 28. Tumour samples from the other cohorts were collected on day 18 for PCR array, qRT-PCR, western blotting and immunofluorescent assessment. Propofol treatment reduced tumour size (mean ± SD; 23.0 ± 6.2mm3) when compared to sevoflurane (36.0 ± 0.3mm3) (p = 0.008) or control (23.6 ± 4.7mm3). Propofol decreased hypoxia inducible factor 1α (HIF1α), interleukin 1β (IL1β), and hepatocyte growth factor (HGF) gene expressions and increased tissue inhibitor of metalloproteinases 2 (TIMP-2) gene and protein expression in comparison to sevoflurane in the tumour tissue. LPS suppressed tumour growth in any conditions whilst increased TIMP-2 and anti-cancer neutrophil marker expressions and decreased macrophage marker expressions compared to those in the LPS-untreated groups. Our data indicated that sevoflurane increased cancer development when compared with propofol in vivo under non-surgical condition. Anaesthetics tested in this study did not alter the effects of LPS as an immune modulator in changing immunocyte phenotype and suppressing cancer development.

Effect of perioperative cognitive behavioural therapy on chronic post-surgical pain among breast cancer patients with high pain catastrophising characteristics: protocol for a double-blinded randomised controlled trial

BACKGROUND

Surgery is regarded as the primary treatment for breast cancer. Chronic post-surgical pain (CPSP) is a recognised complication after breast cancer surgery, and it is estimated to affect 20-30% of women. Pain catastrophizing has emerged as one of the most influential psychological variables associated with CPSP.

METHODS

This trial will be a single-centre, prospective, double-blinded, superiority, randomised controlled trial (RCT). Patients scheduled for elective breast cancer surgery (wide local excision or mastectomy with or without axillary lymph node dissection) will be screened preoperatively for high pain catastrophising. Patients with high pain catastrophising, defined as a score of ≥ 24 on the Pain Catastrophising Scale will be deemed eligible for inclusion in the study. Participants will be randomly assigned to receive either a cognitive behavioural therapy or an educational mindfulness based programme during their perioperative period. The primary outcome is the Brief Pain Inventory short form average pain severity score at 3 months postoperatively. Secondary outcomes include patient-reported quality of recovery at days 1-2 after surgery, levels of pain catastrophising, reported depressed mood and anxiety.

DISCUSSION

To the best of our knowledge, this protocol describes the first RCT which directly examines the effect of perioperative cognitive behavioural therapy on CPSP among breast cancer patients with high pain catastrophising characteristics. The outcomes of this trial may have significant implications for these patients because perioperative cognitive behavioural therapy has the potential to become an important perioperative intervention to complement patient management.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04924010 . Registered on 11 June 2021. All item from the World Health Organisation Trial Registration Data set have been included.

Association Between Anesthetic Dose and Technique and Oncologic Outcomes After Surgical Resection of Non-Small Cell Lung Cancer

OBJECTIVES

Because of the biologic effects of volatile anesthetics on the immune system and cancer cells, it has been hypothesized that their use during non-small cell lung cancer (NSCLC) surgery may negatively affect cancer outcomes compared with total intravenous anesthesia (TIVA) with propofol. The present study evaluated the relationship between anesthetic technique and dose and oncologic outcome in NSCLC surgery.

DESIGN

Retrospective cohort study.

SETTING

Surgical records collated from a single, tertiary care hospital and combined with the Scottish Cancer Registry and continuously recorded electronic anesthetic data.

PARTICIPANTS

Patients undergoing elective lung resection for NSCLC between January 2010 and December 2014.

INTERVENTIONS

The cohort was divided into patients receiving TIVA only and patients exposed to volatile anesthetics.

MEASUREMENTS AND MAIN RESULTS

Final analysis included 746 patients (342 received TIVA and 404 volatile anesthetic). Kaplan-Meier survival curves with log-rank testing were drawn for cancer-specific and overall survival. No significant differences were demonstrated for either cancer-specific (p = 0.802) or overall survival (p = 0.736). Factors influencing survival were analyzed using Cox proportional hazards modeling. Anesthetic type was not a significant predictor for cancer-specific or overall survival in univariate or multivariate Cox analysis. Volatile anesthetic exposure was quantified using area under the end-tidal expired anesthetic agent versus time curves. This was not significantly associated with cancer-specific survival on univariate (p = 0.357) or multivariate (p = 0.673) modeling.

CONCLUSIONS

No significant relationship was demonstrated between anesthetic technique and NSCLC survival. Whether a causal relationship exists between anesthetic technique during NSCLC surgery and oncologic outcome warrants definitive investigation in a prospective, randomized trial.

Impact of perioperative pain management on cancer recurrence: an ASRA/ESRA special article

Cancer causes considerable suffering and 80% of advanced cancer patients experience moderate to severe pain. Surgical tumor excision remains a cornerstone of primary cancer treatment, but is also recognized as one of the greatest risk factors for metastatic spread. The perioperative period, characterized by the surgical stress response, pharmacologic-induced angiogenesis, and immunomodulation results in a physiologic environment that supports tumor spread and distant reimplantation.In the perioperative period, anesthesiologists may have a brief and uniquewindow of opportunity to modulate the unwanted consequences of the stressresponse on the immune system and minimize residual disease. This reviewdiscusses the current research on analgesic therapies and their impact ondisease progression, followed by an evidence-based evaluation of perioperativepain interventions and medications.

How Anesthetic, Analgesic and Other Non-Surgical Techniques During Cancer Surgery Might Affect Postoperative Oncologic Outcomes: A Summary of Current State of Evidence

The question of whether anesthetic, analgesic or other perioperative intervention during cancer resection surgery might influence long-term oncologic outcomes has generated much attention over the past 13 years. A wealth of experimental and observational clinical data have been published, but the results of prospective, randomized clinical trials are awaited. The European Union supports a pan-European network of researchers, clinicians and industry partners engaged in this question (COST Action 15204: Euro-Periscope). In this narrative review, members of the Euro-Periscope network briefly summarize the current state of evidence pertaining to the potential effects of the most commonly deployed anesthetic and analgesic techniques and other non-surgical interventions during cancer resection surgery on tumor recurrence or metastasis.

After a Sharp Decline in HPV Vaccine Rates From 87% to 50%, Irish Health Experts, Politicians and NGOs Joined Forces To Turn The Tide, Helping to Increase Vaccination by 11%. This Is How We Did It

Background and context: Just three years ago, in 2015, HPV vaccination uptake in Ireland was running at 87%. The school-based program was going well, and thousands of girls had completed a two-dose vaccination course which will significantly reduce their risk of cervical cancer and other HPV-related diseases. This was achieved with limited public health messaging. Then an online campaign to undermine the vaccine began to gather momentum. A small number of stories surfaced on social media claiming links between the timing of the vaccination campaigns and the subsequent development of illnesses. The campaign against the vaccine went viral on social media, local radio - and, in November 2015, on a commercial television station - fear began to trump science. In the summer of 2016, when preliminary figures showed uptake had hit 50%, the Irish Cancer Society commenced a campaign to take decisive action. Aim: To reverse the decline in HPV vaccine and restore uptake to previous levels above 80%. Strategy/Tactics: For health campaigners, such as the Irish Cancer Society, the problem of falling HPV vaccine uptake was a perplexing one. The society had pushed hard for the introduction of the HPV vaccine which commenced in 2011. To address the problem the Irish Cancer Society developed an advocacy campaign which eventually led to the establishment of the HPV Vaccination Alliance, a large group of leading health, children and women's groups, with the aim of ensuring that the public saw a broad coalition standing up for the vaccine. The Alliance has simple and consistent messages - including the fact that 40 women will die each year as a result of parents opting out of the vaccination program. Work was done to ensure that politicians were strongly supportive of the vaccine including political briefings with politicians who had previously sought to question its effectiveness. Young women with cervical cancer endorsed the campaign. The Minister for Health strongly endorsed the vaccine. The credibility of support groups for those with reported side effects of the vaccine was undermined by highlighting their links with national and international antivaccine activists as well as highlighting their repeated refusal to answer questions about where they spent money raised from the general public. Outcomes: Figures show uptake of the vaccine has increased to 61% in 2017 - up from 50% in 2016. What was learned: Not enough was done to support the initial implementation of the vaccine which created an information vacuum and under informed vaccination teams. The answer was a classic example of good public health advocacy in action demonstrating the power of alliances delivering consistent, clear and simple messaging.

Tight intra-operative blood pressure control versus standard care for patients undergoing hip fracture repair - Hip Fracture Intervention Study for Prevention of Hypotension (HIP-HOP) trial: study protocol for a randomised controlled trial

Background

Hypotension during anaesthesia for hip fracture surgery is common. Recent data suggest that there is an association between the lowest intra-operative blood pressure and mortality, even when adjusted for co-morbidities. This is consistent with data derived from the wider surgical population, where magnitude and duration of hypotension are associated with mortality and peri-operative complications. However, there are no trial to data to support more aggressive blood pressure control.

Methods/design

We are conducting a three-centre, randomised, double-blinded pilot study in three hospitals in the United Kingdom. The sample size will be 75 patients (25 from each centre). Randomisation will be done using computer-generated concealed tables. Both participants and investigators will be blinded to group allocation. Participants will be aged >70 years, cognitively intact (Abbreviated Mental Test Score 7 or greater), able to give informed consent and admitted directly through the emergency department with a fractured neck of the femur requiring operative repair. Patients randomised to tight blood pressure control or avoidance of intra-operative hypotension will receive active treatment as required to maintain both of the following: systolic arterial blood pressure >80% of baseline pre-operative value and mean arterial pressure >75 mmHg throughout. All participants will receive standard hospital care, including spinal or general anaesthesia, at the discretion of the clinical team. The primary outcome is a composite of the presence or absence of defined cardiovascular, renal and delirium morbidity within 7 days of surgery (myocardial injury, stroke, acute kidney injury, delirium). Secondary endpoints will include the defined individual morbidities, mortality, early mobility and discharge to usual residence.

Discussion

This is a small-scale pilot study investigating the feasibility of a trial of tight intra-operative blood pressure control in a frail elderly patient group with known high morbidity and mortality. Positive findings will provide the basis for a larger-scale study.

Trial registration

ISRCTN Registry identifier: ISRCTN89812075. Registered on 30 August 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2066-5) contains supplementary material, which is available to authorized users.

Synovial tissue hypoxia and inflammation in vivo

INTRODUCTION

Hypoxia is a microenvironmental feature in the inflamed joint, which promotes survival advantage for cells. The aim of this study was to examine the relationship of partial oxygen pressure in the synovial tissue (tPO(2)) in patients with inflammatory arthritis with macroscopic/microscopic inflammation and local levels of proinflammatory mediators.

METHODS

Patients with inflammatory arthritis underwent full clinical assessment and video arthroscopy to quantify macroscopic synovitis and measure synovial tPO(2) under direct visualisation. Cell specific markers (CD3 (T cells), CD68 (macrophages), Ki67 (cell proliferation) and terminal deoxynucleotidyl transferase dUTP nick end labelling (cell apoptosis)) were quantified by immunohistology. In vitro migration was assessed in primary and normal synoviocytes (synovial fibroblast cells (SFCs)) using a wound repair scratch assay. Levels of tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta), interferon gamma (IFNgamma), IL6, macrophage inflammatory protein 3alpha (MIP3alpha) and IL8 were quantified, in matched serum and synovial fluid, by multiplex cytokine assay and ELISA.

RESULTS

The tPO(2) was 22.5 (range 3.2-54.1) mm Hg and correlated inversely with macroscopic synovitis (r=-0.421, p=0.02), sublining CD3 cells (-0.611, p<0.01) and sublining CD68 cells (r=-0.615, p<0.001). No relationship with cell proliferation or apoptosis was found. Primary and normal SFCs exposed to 1% and 3% oxygen (reflecting the median tPO(2) in vivo) induced cell migration. This was coupled with significantly higher levels of synovial fluid tumour necrosis factor alpha (TNFalpha), IL1beta, IFNgamma and MIP3alpha in patients with tPO(2) <20 mm Hg (all p values <0.05).

CONCLUSIONS

This is the first study to show a direct in vivo correlation between synovial tPO(2), inflammation and cell migration, thus it is proposed that hypoxia is a possible primary driver of inflammatory processes in the arthritic joint.

Bolus remifentanil for chest drain removal in ICU: a randomized double-blind comparison of three modes of analgesia in post-cardiac surgical patients

PURPOSE

We compared 1 versus 0.5 microg/kg bolus remifentanil versus placebo in alleviating pain due to chest drain removal. Effects on sedation, respiratory rate (RR), oxygen saturation, heart rate (HR) and blood pressure were also evaluated.

METHODS

Sixty patients following cardiac surgery were enrolled in this prospective, randomized, double-blind clinical trial. Patients were randomized to 1 or 0.5 microg/kg remifentanil or placebo. All received standardized analgesia. Visual analog scale (VAS) pain scores and cardio-respiratory data were recorded pre-procedure, at drain removal and at 2 min intervals post procedure.

RESULTS

Patients receiving remifentanil had statistically significantly less pain than placebo at drain removal [median (25-75%) VAS: 0.5 microg/kg remifentanil 1 (0-2) versus placebo 5 (3-6), P = 0.001; 1.0 microg/kg remifentanil 0 (0-2) versus placebo 5 (3-6), P = 0.0001]. VAS scores between remifentanil groups were equivalent. Remifentanil 1 microg/kg versus placebo at drain removal revealed significant reductions in HR [mean +/- standard deviation (SD): 76 +/- 15 versus 92 +/- 10, P = 0.01], blood pressure [mean +/- SD: 103 +/- 22 versus 131 +/- 14, P = 0.01] and RR [median (25-75%): 10 (8-12) versus 16 (14-18), P = 0.001]. Remifentanil 0.5 microg/kg versus placebo at drain removal revealed significant reductions in blood pressure [mean +/- SD: 116 +/- 19 versus 131 +/- 14, P = 0.02] and RR [median (25-75%): 12 (10-13) versus 18 (16-18), P = 0.001]. SpO(2) at drain removal was significantly reduced when comparing 1 microg/kg remifentanil versus placebo [median (25-75%): 94 (88-97) versus 97 (96-98), P = 0.049] but not 0.5 microg/kg remifentanil versus placebo. Two patients became apnoeic following 1 microg/kg remifentanil, necessitating respiratory support. Sedation scores in all groups were similar.

CONCLUSIONS

Bolus remifentanil at the tested doses delivers excellent analgesia, but 1 microg/kg remifentanil results in respiratory depression. Remifentanil bolus at 0.5 microg/kg is safe and effective for chest drain removal after heart surgery in ICU.

The impact of intraoperative transoesophageal echocardiography on decision-making during cardiac surgery

BACKGROUND

Real time intraoperative transoesophageal echocardiograpgy (TOE) has an expanding role in peri-operative management and surgical decision making.

OBJECTIVES

Studies of the effect of transoesophageal echocardiography (TOE) on intraoperative decision making commonly emphasise major changes in operative plans. We examined more subtle effects using a novel scale, recording influences on management as follows: Level 1: TOE had no effect on management, confirmed and quantified known pathology. Level 2: TOE altered hemodynamic and/or anesthetic management. Level 3: TOE evaluated the adequacy of surgical intervention/or repair. Level 4: TOE led to an alteration in the surgical plan. We compared the impact of TOE as an aid to intra-operative management in coronary artery bypass cases with other types of cardiac surgery.

METHODS

Retrospective, observational study in a single centre, university-affiliated hospital included 319 patients undergoing cardiac surgery and suitable for TOE. TOE was performed in each patient before and after the institution of cardiopulmonary by-pass. Normal and abnormal echocardiographic findings as well as immediate outcomes of the surgical procedure were recorded using a standard database form. Instances where TOE lead to alteration in operative management were documented. The findings were also compared with those documented on preoperative echocardiography.

RESULTS

In 141 CABG patients TOE had a level 1 impact in 73%, level 2 impact in 11.6%, levels 3 and 4 in 7% and 7.8% respectively. In 178 non CABG patients these values were 2%, 1.6%, (p < 0.05), 72.4% (p < 0.05) and 23.6% (p < 0.05) respectively.

CONCLUSION

The impact of TOE in CABG procedures, while significantly less than that in non-CABG surgical procedures, remains substantial.

Vascular erosion by central venous catheters used for total parenteral nutrition

OBJECTIVE

To establish the incidence of central venous catheter erosion in a patient cohort receiving total parenteral nutrition and to examine risk factors and complications of vascular erosion.

DESIGN AND SETTING

Review of prospectively collected intravenous nutrition service audit records in a tertiary university hospital.

RESULTS

Records of 1,499 patients (2,992 catheters) were studied over the 14 year period 1991-2005. Fisher's exact test was used to determine statistical significance. Five erosions occurred, representing an incidence of 0.17% per catheter or 0.28 per 1,000 catheter days. One of the five patients died from ensuing complications. Mean time to onset of symptoms was 3.6 days following catheter insertion. Symptoms/signs included dyspnoea (n=5), chest pain (n=2) and pleural effusion (n=5). Diagnosis was delayed by a mean of 1.6 days. Three erosions occurred in left subclavian catheters (n=583); two in left internal jugular catheters (n=453). None occurred in right-sided catheters (n=1956). The relative risk of erosion occurring in left-sided catheters compared to right was 2.9 (95% CI 2.76-3.00; p=0.009). There was no statistically significantly greater risk of vascular erosion in subclavian than internal jugular catheters (relative risk 0.9; p=1.0). Older age was a statistically significant risk factor (p=0.009); female sex was not (p=0.18).

CONCLUSION

In patients receiving total parenteral nutrition via central venous catheters, erosion has an incidence per catheter of 0.17% and is more likely to occur in left-sided catheters and elderly patients.

Effect of intraoperative intravenous crystalloid infusion on postoperative nausea and vomiting after gynaecological laparoscopy: comparison of 30 and 10 ml kg(-1)

BACKGROUND

I.V. fluid administration has been shown to reduce postoperative nausea and vomiting (PONV). The optimum dose is unknown. We tested the hypothesis that administration of i.v. crystalloid of 30 ml kg(-1) would reduce the incidence of PONV compared with 10 ml kg(-1) of the same fluid.

METHODS

A total of 141 ASA I female patients undergoing elective gynaecological laparoscopy were randomized, in double-blind fashion, to receive either 10 ml kg(-1) (n=71; CSL-10 group) or 30 ml kg(-1) (n=70; CSL-30 group) of i.v. compound sodium lactate (CSL).

RESULTS

In the first 48 h after anaesthesia, the incidence of vomiting was lower in the CSL-30 group than in the CSL-10 group (8.6% vs 25.7%, P=0.01). Anti-emetic use was less in the CSL-30 group at 0.5 h (2.9% vs 14.3%, P=0.04). The incidence of severe nausea was significantly reduced in the treatment group at awakening (2.9% vs 15.7%, P=0.02), 2 h (0.0% vs 8.6%, P=0.04) and cumulatively (5.7% vs 27.1%, P=0.001). The numbers needed to treat to prevent vomiting, severe nausea and antiemetic use in the first 48 h were 6, 5 and 6, respectively.

CONCLUSION

I.V. administration of CSL 30 ml kg(-1) to healthy women undergoing day-case gynaecological laparoscopy reduced the incidence of vomiting, nausea and anti-emetic use when compared with CSL 10 ml kg(-1).

Comparative study of analgesic efficacy and morphine-sparing effect of intramuscular dexketoprofen trometamol with ketoprofen or placebo after major orthopaedic surgery

AIMS

Multimodal analgesia is thought to produce balanced and effective postoperative pain control. A combined therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) and opiates could result in synergistic analgesia by acting through different mechanisms. Currently there are very few parenterally administered NSAIDs suitable for the immediate postoperative period. Therefore, this study was undertaken to assess the analgesic efficacy, relative potency, and safety of parenteral dexketoprofen trometamol following major orthopaedic surgery.

METHODS

One hundred and seventy-two patients elected for prosthetic surgery, were randomized to receive two intramuscular injections (12 hourly) of either dexketoprofen 50 mg, ketoprofen 100 mg or placebo in a double-blind fashion. Postoperatively, the patient's pain was stabilized, then they were connected to a patient- controlled analgesia system (PCA) of morphine for 24 h (1 mg with 5 min lockout).

RESULTS

The mean cumulative amount of morphine (CAM) used was of 39 mg in the dexketoprofen group and 45 mg in the ketoprofen group vs 64 mg in the placebo group. (Reduction in morphine use was approximately one-third between the active compounds compared with placebo (adjusted mean difference of -25 mg between dexketoprofen and placebo and -23 mg between ketoprofen and placebo. These differences were statistically significant: P </= 0.0003; 95% CI -35, -14. Pain-intensity scores were consistently lower with the active compounds, the lowest corresponded to the dexketoprofen-treated patients. Regarding sedation, there were statistically significant differences between the two active compounds and placebo only at the 2nd and 13th hours. Wound bleeding was specifically measured with no statistically significant differences found between all the groups.

CONCLUSIONS

Intramuscular administration of dexketoprofen trometamol 50 mg has good analgesic efficacy both in terms of opioid-sparing effect and control of pain after major orthopaedic surgery.

Tramadol or fentanyl analgesia for ambulatory knee arthroscopy

In a double-blind, randomized, controlled study, 61 patients who received a standardized anaesthetic for day case arthroscopic knee surgery were studied. Group T (n = 31) received tramadol 1.5 mg kg-1, and group F (n = 30) received fentanyl 1.5 micrograms kg-1 at the induction of anaesthesia. All patients also received 20 mL of intra-articular bupivacaine 0.5% at the end of surgery. Assessments were made of pain at rest and on movement, analgesic requirements and side-effects at hourly intervals up to 6 h and by means of a postal questionnaire at 24 h and 48 h post-operatively. Group F had higher pain scores than group T at 4 h only [VAS 3.3 (1.6-5.5) vs. 2.4 (1-4), P = 0.039, respectively; median (interquartile range)]. There were no other significant differences between the groups in terms of pain scores, supplemental analgesic requirements or incidence of side-effects. We conclude that tramadol offers little benefit clinically compared with fentanyl when used at induction of anaesthesia for day case arthroscopic knee surgery. Further studies are indicated in patients with more severe pain to determine the role of tramadol in post-operative analgesia.

Pre-emptive glycopyrrolate 0.2 mg and bradycardia during gynaecological laparoscopy with mivacurium

In a prospective, randomized, double-blind, placebo-controlled trial, the effect of pre-emptive glycopyrrolate 0.2 mg given intravenously on the incidence of bradycardia in patients undergoing elective gynaecological laparoscopy with mivacurium neuromuscular blockade was investigated. Seven out of 32 (21.6%) control patients developed bradycardia (heart rate < 50 min-1), compared with 3 of 31 (9.6%) patients receiving glycopyrrolate (P = 0.4). Glycopyrrolate 0.2 mg, given immediately before induction in gynaecological laparoscopy with mivacurium, did not significantly reduce the incidence of intraoperative bradycardia.

Acute superior vena caval syndrome with airway obstruction following elective mediastinoscopy

A 47-year-old female patient had a subclinical superior vena caval syndrome which developed into the 'full blown' acute condition when she was placed into the left lateral position after mediastinoscopy. She developed airway obstruction requiring urgent re-intubation and subsequent admission to the intensive care unit. This subclinical condition might have been suspected pre-operatively if closer attention had been paid to the history, physical examination and review of the computerised axial tomography scan: she had a history of intermittent dysponea, wheeze and cough which was worse on waking and improved as the day progressed, she had a positive Pemberton's sign and the computerised axial tomography scan showed that the lesion was encroaching on the superior vena cava.

Clonidine at induction reduces shivering after general anaesthesia

PURPOSE

Postanaesthetic shivering occurs in 5-65% of patients. In addition to causing discomfort, it is associated with deleterious consequences. Our objective was to investigate the effect of 150 micrograms clonidine, at induction of anaesthesia, on perioperative core and peripheral temperature, incidence of postanaesthetic shivering and patients' perception of cold.

METHODS

Sixty ASA 1 or 2 patients scheduled for elective orthopaedic limb surgery were randomly allocated to group 1, who received 150 micrograms clonidine iv, or group 2, who received a saline bolus iv, before induction. In all patients, anaesthesia was induced with fentanyl and propofol and maintained by spontaneous respiration (via a laryngeal mask airway) of oxygen, nitrous oxide and enflurane. Core (nasopharyngeal) and peripheral (dorsal hand) temperatures were recorded at induction and 15-min intervals. Nurses, unaware of the treatment groups, recorded visible shivering in the recovery room. When cognitive function returned, patients were asked to grade their perception of cold on a 10 cm linear analogue scale, higher scores indicating heat discomfort.

RESULTS

While core temperature decreased and peripheral temperature increased in both groups, there was no difference between the groups at any time. However, there was a lower incidence of shivering in the clonidine group (20% vs 66.7%, P < 0.001). Patients receiving clonidine felt warmer; thermal comfort score (median interquartile range) 5.9 (5.0-7.2) vs 5.0 (4.5-6.0), P < 0.05).

CONCLUSION

Clonidine 150 g iv at induction of anaesthesia reduces the incidence of shivering and patients' subjective perception of cold on emergence from general anaesthesia.

Prevention of spinal anesthesia-induced hypotension in the elderly: comparison between preanesthetic administration of crystalloids, colloids, and no prehydration

The practice of routinely prehydrating patients by infusing a crystalloid or colloid solution (up to 1.0 L/70 kg) for prevention of spinal anesthesia-induced hypotension has been challenged recently, after several reports of failure to demonstrate its efficacy in young women. We compared the incidence and frequency of hypotension and vasopressor therapy after spinal anesthesia and no prehydration with crystalloid and colloid prehydration in elderly patients. Eighty-five ASA grade I or II patients (aged 60-89 yr) for elective total hip replacement were randomized to receive 500 mL crystalloid solution (Hartmanns, n = 29), 500 mL colloid (Haemaccel, n = 28), or no prehydration (n = 28) over 10 min prior to spinal anesthesia. Hypotension was defined as a 30% decrease from baseline systolic blood pressure (BP) or systolic < 90 mm Hg, and was treated with ephedrine 3-mg boluses. Although absolute systolic BP readings were significantly higher in the colloid group between 6 and 30 min (P < 0.05), the incidence of hypotension was not significantly different between the groups. The incidence of ephedrine use, incidence of nausea/vomiting, and median total dose of ephedrine were similar in all groups. We conclude that, in elderly patients undergoing elective procedures, withholding prehydration is not associated with any greater degree of hypotension or need for vasopressor therapy compared with crystalloid or colloid prehydration.

Patient attitudes to perioperative suppository administration for postoperative analgesia

Four hundred surgical patients were questioned preoperatively to ascertain their attitudes to suppository analgesia. Given a choice, 82 per cent of patients expressed a preference for intramuscular administration of diclofenac, with 18 per cent choosing a suppository. Males were more likely than females to choose an intramuscular injection. Males choosing a suppository were more likely to belong to a higher socio-economic group while females choosing a suppository were more likely to be married. Twenty-three per cent of patients who initially opted for intramuscular administration changed to suppository administration when the possibility of pain or discomfort at the injection site was explained. Females who changed to suppository administration were more likely to belong to a higher socio-economic group and to be married. Twenty-seven per cent of patients choosing an intramuscular injection expressed concern if a suppository were to be inserted without consent. Eleven per cent of patients choosing a suppository expressed similar concern. There is an overall reluctance, particularly within the male population to accept suppository analgesia. Patients from higher socio-economic groups may be more willing to accept what they perceive to be less traditional forms of treatment.

Do epidurals cause back pain?

Postpartum back pain may occur in up to 44% of women after childbirth. The increasing use of epidural analgesia during labour over the past 35 years has led many women and some doctors to attribute postpartum back pain to this. Such suggestions, if unfounded, may undermine parturients' confidence in epidural analgesia. However, the outcome of recent, randomized studies clearly shows that epidural analgesia does not cause back pain.

Back pain and pregnancy: a review

Back pain is a common symptom in association with pregnancy. This article reviews the pathogenesis of back pain during pregnancy (gestational back pain) and of new onset postpartum back pain. The studies implicating epidural analgesia and postpartum back pain are discussed. Possible physiological mechanisms contributing to gestational back pain are outlined. Guidelines are provided for the prevention and symptomatic management of the back pain syndromes of pregnancy.

The space blanket and shivering during extradural analgesia in labour

The incidence of shivering in women during epidural analgesia in labour is up to 33%, and may be highly distressing. Its mechanism is unclear, but the most widely held theory is that it is thermogenic. Pharmacological suppression may adversely effect the foetus or induce maternal hypothermia, and although physical remedies such as direct heat application are effective, they are also expensive and cumbersome. We recently found that the space blanket, a simple aluminised metallic foil, used pre-emptively, reduces shivering after general anaesthesia. We investigated the effect of the space blanket on the incidence and intensity of shivering, axilliary skin temperature, and subjective perception of cold during epidural analgesia for labour in 50 women over a four-hour time frame. Patients were randomised into group 1, who were wrapped in a space blanket immediately after commencement of epidural analgesia with bupivacaine, and group 2 (matched controls). Shivering was defined as visible tremor of the head, neck, trunk or limbs as observed by the attending midwives. Twenty-nine percent of group 1 and 35% of group 2 shivered (not significant), but a reduction in shivering intensity was observed in group 1 (P < 0.05). There was no significant difference in skin temperatures in either group, and no significant temperature change within the groups. Both groups had similar thermal comfort scores throughout the study, which correlated poorly with the presence of shivering. We conclude that there is no benefit in application of the space blanket to reduce epidural-analgesia related shivering in labour, which may indicate a non-thermogenic mechanism for this phenomenon.

Posterior column sensory impairment during ambulatory extradural analgesia in labour

Ambulatory or "walking" extradural analgesia in labour has recently gained popularity because of preservation of motor function and subjective somatic sensation in the lower limbs, resulting in increased maternal satisfaction. This is produced by combining dilute concentrations (e.g. 0.1%) of bupivacaine with opioids. Detailed clinical neurological examination after mobile extradural analgesia has not been reported. We have investigated the effect of 0.1% bupivacaine 15 ml and fentanyl 2 micrograms ml-1 on motor and sensory function in the lower limbs in 50 primigravidae requesting extradural analgesia in labour. This was performed before and 30 min after confirming placement of a lumbar extradural catheter. While power, co-ordination and reflexes in all lower limb muscle groups remained within normal limits, 66% (n = 33) developed abnormal distal proprioception, 44% (n = 22) had a positive Romberg's sign and 38% (n = 19) had altered vibration sense. Moreover, 44% (n = 22) said that their legs felt different on standing and they did not feel confident walking unaccompanied. However, this subjective perception correlated poorly with the presence of posterior column sensory signs. Although there was a reduction in pain scores on a visual analogue scale after 30 min (mean 8.85 (SEM 0.3) vs 3.06 (0.32); P < 0.0001), pain increased within 60 min (5.77 (0.45); P < 0.001).

Acute inhibitory effect of alcohol on sodium-lithium countertransport

To assess a possible acute effect of environmental factors on sodium-lithium countertransport (SLC), we determined the activity of this transport system in 14 healthy volunteers, who are nonhabitual drinkers, before and 1 hour after intake of alcohol (0.8g/kg) with "Coke" as the vehicle. Alcohol significantly increased the "leak pathway" component of lithium efflux from a baseline value of 0.21 +/- 0.02 to 0.24 +/- 0.02 mmol/Lcell.h(p < 0.003); and reduced the Vmax of the transporter (0.38 +/- 0.05 to 0.31 +/- 0.04mmol/Lcell.h;p < 0.0005) without significantly changing its affinity for external sodium. The reduction in Vmax was dependent on the initial activity of the transporter (r2 = 0.5). A plot of reduction in Vmax against the product of initial Vmax value and blood alcohol level in each subject revealed a stronger relationship (r2 = 0.86), suggesting that the observed change in Vmax was also dependent on blood alcohol level. Coke alone did not change any of the parameters. We conclude that alcohol acutely inhibits SLC as well as alters erythrocyte membrane in a manner that increases passive lithium efflux.

Pre-emptive use of the space blanket reduces shivering after general anaesthesia

We have investigated the role of aluminized metal foil (space blanket, UN 320), used pre-emptively, in post-anaesthetic shivering and patients' subjective perception of cold after general anaesthesia of short duration. Sixty-eight ASA I and II patients undergoing orthopaedic and plastic surgery on the peripheries were allocated randomly to two groups: those in group 1 were wrapped (not less than 60% of body surface area) in the space blanket before induction of anaesthesia. In group 2 patients had standard surgical draping. In all subjects, anaesthesia was induced with fentanyl and propofol, and maintained with nitrous oxide and enflurane in oxygen, after a laryngeal mask airway was positioned. Patients were asked to grade their perception of cold on a visual analogue scale, before induction and on recovery. Skin (dorsum of hand) and core (nasopharyngeal) temperatures were recorded at 15-min intervals. Occurrence of shivering and cold scores were recorded by blinded observers. Groups were similar in age and gender; duration of anaesthesia was also similar (mean 41.6 (SEM 4.8) vs 47.5 (3.3) min, respectively). The incidences of shivering were 15% and 63% in groups 1 and 2, respectively (P < 0.001). Cold scores were 2.4 (0.4) and 5.7 (0.5), respectively (P < 0.001). Skin temperatures increased with increasing duration of anaesthesia in both groups but were greater at 15, 30 and 45 min in group 1 (33.38 (0.25) vs 31.56 (0.31), 34.46 (0.25) vs 32.45 (0.31) and 35.22 (0.36) vs 33.13 (0.34), respectively; P < 0.001 each comparison). Core temperature increased slightly in group 1 and decreased in group 2 (P = 0.11).(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoprotein(a) and treatment of chronic renal disease

OBJECTIVES

To compare lipoprotein(a) [Lp(a)] and albumin concentrations in patients with chronic renal disease receiving different forms of treatment and to determine, if any, the relationship between these variables.

DESIGN

A prospective cross-sectional, case-controlled study.

SETTING

A tertiary referral nephrology and dialysis unit.

SUBJECTS

Forty-four consecutive non-diabetic patients with chronic renal failure treated by renal transplantation (n = 18), haemodialysis (n = 18), continuous ambulatory peritoneal dialysis (CAPD; n = 8), and 30 healthy controls from subjects drawn from University personnel were studied.

INTERVENTIONS

Fasting morning venous blood was analysed for Lp(a), albumin, total cholesterol and glucose concentrations.

MAIN OUTCOME MEASURES

Comparison of plasma levels of these variables between the sub-groups.

RESULTS

Concentrations (median; 95% CI) of Lp(a) were significantly (P < 0.05) higher (38.4 mg dl-1; range 15.4-72.0) and of albumin lower (31.6 g l-1; range 28-35.2) in the CAPD group compared with both control subjects and other groups of chronic renal disease patients.

CONCLUSIONS

The elevated Lp(a) concentrations seen only in association with reduced albumin concentrations in CAPD patients suggest a regulatory role for albumin with albumin losses stimulating production of Lp(a).