Early Warning Scores to Support Continuous Wireless Vital Sign Monitoring for Complication Prediction in Patients on Surgical Wards: Retrospective Observational Study

BACKGROUND

Wireless vital sign sensors are increasingly being used to monitor patients on surgical wards. Although early warning scores (EWSs) are the current standard for the identification of patient deterioration in a ward setting, their usefulness for continuous monitoring is unknown.

OBJECTIVE

This study aimed to explore the usability and predictive value of high-rate EWSs obtained from continuous vital sign recordings for early identification of postoperative complications and compares the performance of a sensor-based EWS alarm system with manual intermittent EWS measurements and threshold alarms applied to individual vital sign recordings (single-parameter alarms).

METHODS

Continuous vital sign measurements (heart rate, respiratory rate, blood oxygen saturation, and axillary temperature) collected with wireless sensors in patients on surgical wards were used for retrospective simulation of EWSs (sensor EWSs) for different time windows (1-240 min), adopting criteria similar to EWSs based on manual vital signs measurements (nurse EWSs). Hourly sensor EWS measurements were compared between patients with (event group: 14/46, 30%) and without (control group: 32/46, 70%) postoperative complications. In addition, alarms were simulated for the sensor EWSs using a range of alarm thresholds (1-9) and compared with alarms based on nurse EWSs and single-parameter alarms. Alarm performance was evaluated using the sensitivity to predict complications within 24 hours, daily alarm rate, and false discovery rate (FDR).

RESULTS

The hourly sensor EWSs of the event group (median 3.4, IQR 3.1-4.1) was significantly higher (P<.004) compared with the control group (median 2.8, IQR 2.4-3.2). The alarm sensitivity of the hourly sensor EWSs was the highest (80%-67%) for thresholds of 3 to 5, which was associated with alarm rates of 2 (FDR=85%) to 1.2 (FDR=83%) alarms per patient per day respectively. The sensitivity of sensor EWS-based alarms was higher than that of nurse EWS-based alarms (maximum=40%) but lower than that of single-parameter alarms (87%) for all thresholds. In contrast, the (false) alarm rates of sensor EWS-based alarms were higher than that of nurse EWS-based alarms (maximum=0.6 alarm/patient/d; FDR=80%) but lower than that of single-parameter alarms (2 alarms/patient/d; FDR=84%) for most thresholds. Alarm rates for sensor EWSs increased for shorter time windows, reaching 70 alarms per patient per day when calculated every minute.

CONCLUSIONS

EWSs obtained using wireless vital sign sensors may contribute to the early recognition of postoperative complications in a ward setting, with higher alarm sensitivity compared with manual EWS measurements. Although hourly sensor EWSs provide fewer alarms compared with single-parameter alarms, high false alarm rates can be expected when calculated over shorter time spans. Further studies are recommended to optimize care escalation criteria for continuous monitoring of vital signs in a ward setting and to evaluate the effects on patient outcomes.

Performance and usability of pre-operative prediction models for 30-day peri-operative mortality risk: a systematic review

Estimating pre-operative mortality risk may inform clinical decision-making for peri-operative care. However, pre-operative mortality risk prediction models are rarely implemented in routine clinical practice. High predictive accuracy and clinical usability are essential for acceptance and clinical implementation. In this systematic review, we identified and appraised prediction models for 30-day postoperative mortality in non-cardiac surgical cohorts. PubMed and Embase were searched up to December 2022 for studies investigating pre-operative prediction models for 30-day mortality. We assessed predictive performance in terms of discrimination and calibration. Risk of bias was evaluated using a tool to assess the risk of bias and applicability of prediction model studies. To further inform potential adoption, we also assessed clinical usability for selected models. In all, 15 studies evaluating 10 prediction models were included. Discrimination ranged from a c-statistic of 0.82 (MySurgeryRisk) to 0.96 (extreme gradient boosting machine learning model). Calibration was reported in only six studies. Model performance was highest for the surgical outcome risk tool (SORT) and its external validations. Clinical usability was highest for the surgical risk pre-operative assessment system. The SORT and risk quantification index also scored high on clinical usability. We found unclear or high risk of bias in the development of all models. The SORT showed the best combination of predictive performance and clinical usability and has been externally validated in several heterogeneous cohorts. To improve clinical uptake, full integration of reliable models with sufficient face validity within the electronic health record is imperative.

Nurses' experiences with continuous vital sign monitoring on the general surgical ward: a qualitative study based on the Behaviour Change Wheel

Background

To support early recognition of clinical deterioration on a general ward continuous vital signs monitoring (CMVS) systems using wearable devices are increasingly being investigated. Although nurses play a crucial role in successful implementation, reported nurse adoption and acceptance scores vary significantly. In-depth insight into the perspectives of nurses regarding CMVS is lacking. To this end, we applied a theoretical approach for behaviour change derived from the Behaviour Change Wheel (BCW).

Aim

To provide insight in the capability, opportunity and motivation of nurses working with CMVS, in order to inform future implementation efforts.

Methods

A qualitative study was conducted, including twelve nurses of a surgical ward in a tertiary teaching hospital with previous experience of working with CMVS. Semi-structured interviews were audiotaped, transcribed verbatim, and analysed using thematic analysis. The results were mapped onto the Capability, Opportunity, Motivation – Behaviour (COM-B) model of the BCW.

Results

Five key themes emerged. The theme ‘Learning and coaching on the job’ linked to Capability. Nurses favoured learning about CVSM by dealing with it in daily practice. Receiving bedside guidance and coaching was perceived as important. The theme ‘interpretation of vital sign trends’ also linked to Capability. Nurses mentioned the novelty of monitoring vital sign trends of patients on wards. The theme ‘Management of alarms’ linked to Opportunity. Nurses perceived the (false) alarms generated by the system as excessive resulting in feelings of irritation and uncertainty. The theme ‘Integration and compatibility with clinical workflow’ linked to Opportunity. CVSM was experienced as helpful and easy to use, although integration in mobile devices and the EMR was highly favoured and the management of clinical workflows would need improvement. The theme ‘Added value for nursing care’ linked to Motivation. All nurses recognized the potential added value of CVSM for postoperative care.

Conclusion

Our findings suggest all parts of the COM-B model should be considered when implementing CVSM on general wards. When the themes in Capability and Opportunity are not properly addressed by selecting interventions and policy categories, this may negatively influence the Motivation and may compromise successful implementation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12912-022-00837-x.

Remote Hospital Care for Recovering COVID-19 Patients Using Telemedicine: A Randomised Controlled Trial

BACKGROUND

To ensure availability of hospital beds and improve COVID-19 patients' well-being during the ongoing pandemic, hospital care could be offered at home. Retrospective studies show promising results of deploying remote hospital care to reduce the number of days spent in the hospital, but the beneficial effect has yet to be established.

METHODS

We conducted a single centre, randomised trial from January to June 2021, including hospitalised COVID-19 patients who were in the recovery stage of the disease. Hospital care for the intervention group was transitioned to the patient's home, including oxygen therapy, medication and remote monitoring. The control group received in-hospital care as usual. The primary endpoint was the number of hospital-free days during the 30 days following randomisation. Secondary endpoints included health care consumption during the follow-up period and mortality.

RESULTS

A total of 62 patients were randomised (31 control, 31 intervention). The mean difference in hospital-free days was 1.7 (26.7 control vs. 28.4 intervention, 95% CI of difference -0.5 to 4.2, p = 0.112). In the intervention group, the index hospital length of stay was 1.6 days shorter (95% CI -2.4 to -0.8, p < 0.001), but the total duration of care under hospital responsibility was 4.1 days longer (95% CI 0.5 to 7.7, p = 0.028).

CONCLUSION

Remote hospital care for recovering COVID-19 patients is feasible. However, we could not demonstrate an increase in hospital-free days in the 30 days following randomisation. Optimising the intervention, timing, and identification of patients who will benefit most from remote hospital care could improve the impact of this intervention.

Postoperative urinary retention: risk factors, bladder filling rate and time to catheterization: an observational study as part of a randomized controlled trial

Background

Knowledge of risk factors for postoperative urinary retention may guide appropriate and timely urinary catheterization. We aimed to determine independent risk factors for postoperative urinary catheterization in general surgical patients. In addition, we calculated bladder filling rate and assessed the time to spontaneous voiding or catheterization. We used the patients previously determined individual maximum bladder capacity as threshold for urinary catheterization.

Methods

Risk factors for urinary catheterization were prospectively determined in 936 general surgical patients. Patients were at least 18 years of age and operated under general or spinal anesthesia without the need for an indwelling urinary catheter. Patients measured their maximum bladder capacity preoperatively at home, by voiding in a calibrated bowl after a strong urge that could no longer be ignored. Postoperatively, bladder volumes were assessed hourly with ultrasound. When patients reached their maximum bladder capacity and were unable to void, they were catheterized by the nursing staff. Bladder filling rate and time to catheterization were determined.

Results

Spinal anesthesia was the main independent modifiable risk factor for urinary catheterization (hyperbaric bupivacaine, relative risk 8.1, articaine RR 3.1). Unmodifiable risk factors were a maximum bladder capacity < 500 mL (RR 6.7), duration of surgery ≥ 60 min (RR 5.5), first scanned bladder volume at the Post Anesthesia Care Unit ≥250mL (RR 2.1), and age ≥ 60 years (RR 2.0). Urine production varied from 100 to 200 mL/h. Catheterization or spontaneous voiding took place approximately 4 h postoperatively.

Conclusion

Spinal anesthesia, longer surgery time, and older age are the main risk factors for urinary retention catheterization. Awareness of these risk factors, regularly bladder volume scanning (at least every 3 h) and using the individual maximum bladder capacity as volume threshold for urinary catheterization may avoid unnecessary urinary catheterization and will prevent bladder overdistention with the attendant risk of lower urinary tract injury.

Trial registration

Dutch Central Committee for Human Studies registered trial database: NL 21058.099.07.

Current Controlled Trials database: Preventing Bladder Catheterization after an Operation under General or Spinal Anesthesia by Using the Patient’s Own Maximum Bladder Capacity as a Limit for Maximum Bladder Volume. ISRCTN97786497. Registered 18 July 2011 -Retrospectively registered. The original study started 19 May 2008, and ended 30 April 2009, when the last patient was included.

Paravertebral catheter versus EPidural analgesia in Minimally invasive Esophageal resectioN: a randomized controlled multicenter trial (PEPMEN trial)

BACKGROUND

Thoracic epidural analgesia is the standard postoperative pain management strategy in esophageal cancer surgery. However, paravertebral block analgesia may achieve comparable pain control while inducing less side effects, which may be beneficial for postoperative recovery. This study primarily aims to compare the postoperative quality of recovery between paravertebral catheter versus thoracic epidural analgesia in patients undergoing minimally invasive esophagectomy.

METHODS

This study represents a randomized controlled superiority trial. A total of 192 patients will be randomized in 4 Dutch high-volume centers for esophageal cancer surgery. Patients are eligible for inclusion if they are at least 18 years old, able to provide written informed consent and complete questionnaires in Dutch, scheduled to undergo minimally invasive esophagectomy with two-field lymphadenectomy and an intrathoracic anastomosis, and have no contra-indications to either epidural or paravertebral analgesia. The primary outcome is the quality of postoperative recovery, as measured by the Quality of Recovery-40 (QoR-40) questionnaire on the morning of postoperative day 3. Secondary outcomes include the QoR-40 questionnaire score Area Under the Curve on postoperative days 1-3, the integrated pain and systemic opioid score and patient satisfaction and pain experience according to the International Pain Outcomes (IPO) questionnaire, and cost-effectiveness. Furthermore, the groups will be compared regarding the need for additional rescue medication on postoperative days 0-3, technical failure of the pain treatment, duration of anesthesia, duration of surgery, total postoperative fluid administration day 0-3, postoperative vasopressor and inotrope use, length of urinary catheter use, length of hospital stay, postoperative complications, chronic pain at six months after surgery, and other adverse effects.

DISCUSSION

In this study, it is hypothesized that paravertebral analgesia achieves comparable pain control while causing less side-effects such as hypotension when compared to epidural analgesia, leading to shorter postoperative length of stay on a monitored ward and superior quality of recovery. If this hypothesis is confirmed, the results of this study can be used to update the relevant guidelines on postoperative pain management for patients undergoing minimally invasive esophagectomy.

TRIAL REGISTRATION

Netherlands Trial Registry, NL8037. Registered 19 September 2019.

Association between delirium and cognitive change after cardiac surgery

Background

Previous studies provide inconsistent data on whether postoperative delirium (POD) is a risk factor for postoperative cognitive decline (POCD). We thus investigated the relationship between POD and cognitive change after cardiac surgery and assessed the relationship between preoperative cognitive domain scores and POD.

Methods

Postoperative delirium was assessed with the Confusion Assessment Method (CAM) adapted for the intensive care unit and the conventional CAM accompanied by chart review. Cognitive function was assessed with a neuropsychological test battery before elective cardiac surgery and 1 month and 1 yr afterwards. Cognitive change was calculated using the Reliable Change Index (RCI). Multiple linear regression was used to adjust for confounding.

Results

Of the 184 patients who completed baseline assessment, 23 (12.5%) developed POD. At 1 month, the decline in cognitive performance was worse in patients with POD [median composite RCI -1.00, interquartile range (IQR) -1.67 to 0.28] than in patients without POD (RCI -0.04, IQR -0.70 to 0.63, P =0.02). At 1 yr, both groups showed cognitive improvement on average compared with baseline (POD patients median composite RCI 0.25, IQR -0.42 to 1.31, vs non-POD patients RCI 0.92, IQR 0.18-1.53; P =0.08). Correction for differences in age and level of education did not change the results. Patients with POD performed less well than patients without POD on the preoperative Trailmaking test part A ( P =0.03).

Conclusions

Postoperative delirium is independently associated with cognitive decline 1 month after surgery, but cognitive performance generally recovers in 1 yr. Patients with a predisposition to POD can be identified before surgery by worse performance in an attention task.

Clinical trial registration

NCT00293592.

Long-term outcomes and cost effectiveness of high-dose dexamethasone for cardiac surgery: a randomised trial

Prophylactic intra-operative administration of dexamethasone may improve short-term clinical outcomes in cardiac surgical patients. The purpose of this study was to evaluate long-term clinical outcomes and cost effectiveness of dexamethasone versus placebo. Patients included in the multicentre, randomised, double-blind, placebo-controlled DExamethasone for Cardiac Surgery (DECS) trial were followed up for 12 months after their cardiac surgical procedure. In the DECS trial, patients received a single intra-operative dose of dexamethasone 1 mg.kg^-1 (n = 2239) or placebo (n = 2255). The effects on the incidence of major postoperative events were evaluated. Also, overall costs for the 12-month postoperative period, and cost effectiveness, were compared between groups. Of 4494 randomised patients, 4457 patients (99%) were followed up until 12 months after surgery. There was no difference in the incidence of major postoperative events, the relative risk (95%CI) being 0.86 (0.72-1.03); p = 0.1. Treatment with dexamethasone reduced costs per patient by £921 [€1084] (95%CI £-1672 to -137; p = 0.02), mainly through reduction of postoperative respiratory failure and duration of postoperative hospital stay. The probability of dexamethasone being cost effective compared with placebo was 97% at a threshold value of £17,000 [€20,000] per quality-adjusted life year. We conclude that intra-operative high-dose dexamethasone did not have an effect on major adverse events at 12 months after cardiac surgery, but was associated with a reduction in costs. Routine dexamethasone administration is expected to be cost effective at commonly accepted threshold levels for cost effectiveness.

Effect of intrathecal glucocorticoids on the central glucocorticoid receptor in a rat nerve ligation model

BACKGROUND AND AIMS

Despite widespread use, the efficacy of neuraxial glucocorticoids for neuropathic pain is subject to debate. Since most glucocorticoid actions are mediated through its receptor, we explored the effects of intrathecal methylprednisolone acetate (MPA) on total glucocorticoid receptor (tGR) levels and activation of the glucocorticoid receptor (phosphorylated state=pGR) within the spinal dorsal horn (SDH) and dorsal root ganglion (DRG) in a spinal nerve ligation (SNL) model in rats.

METHODS

Rats received unilateral ligation of the L5/L6 spinal nerves and were treated with two intrathecal doses of either 400μg MPA or 0.9% saline with a 72-h interval. Plantar tactile thresholds were measured over time. Seven days after drug treatment, DRG and SDH were harvested to assess tGR and pGR levels using immunohistochemistry and qPCR.

RESULTS

Allodynia, defined by lowered tactile withdrawal thresholds after SNL, was unaltered by intrathecal MPA. In saline controls, mRNA levels of tGR did not change after SNL in the DRGs or SDH. tGR and pGR protein levels in the SDH however, significantly increased on the ipsilateral side of SNL compared to the contralateral side and to naïve tissue. When treating rats with MPA, tGR mRNA levels were significantly reduced in the SDH compared to saline controls. tGR and pGR protein levels, however were not significantly lower compared to saline controls.

CONCLUSIONS

In intrathecal MPA treated rats, tGR mRNA levels decreased after SNL. However this did not result in lower tGR and pGR protein levels compared to saline controls, and did not decrease ligation-induced mechanical hypersensitivity.

IMPLICATIONS

Intrathecal MPA treatment after SNL did not result in lower tGR and pGR levels within the SDH and DRG compared to saline controls. In present study we did not differentiate between the various isoforms of the GR which might clarify this finding.

Analgesic properties of intrathecal glucocorticoids in three well established preclinical pain models

BACKGROUND AND AIMS

Glucocorticoids, a group of anti-inflammatory agents, are frequently administered in pain medicine. Of interest is the reported activity after intrathecal delivery in patients with neuropathic pain syndromes such as postherpetic neuralgia, though its efficacy is controversial. After the publication of two randomized clinical trials in postherpetic neuralgia patients treated with similar intrathecal methylprednisolone acetate (MPA) dosing regimes with conflicting results; one showing significant pain reduction (Kotani N, Kushikata T, Hashimoto H, Kimura F, Muraoka M, Yodono M, Asai M, Matsuki A: Intrathecal methylprednisolone for intractable postherpetic neuralgia. N Engl J Med 2000;23: 1514-9), the other increased pain sensations (Rijsdijk M, van Wijck AJ, Meulenhoff PC, Kavelaars A, van der Tweel I, Kalkman CJ: No beneficial effect of intrathecal methylprednisolone acetate in postherpetic neuralgia patients. Eur J Pain 2013;38: 175-200), we decided additional research was warranted. Present study sought to determine effects of intrathecally delivered methylprednisolone on pain-like behaviour and pain-associated markers in three well established rodent pain models: (1) intraplantar carrageenan, (2) intraplantar formalin, and (3) ligation of L5/L6 spinal nerves (SNL model).

METHODS

Male rats with intrathecal catheters were examined for (1) tactile allodynia after unilateral hindpaw intraplantar carrageenan injection (2%), (2) flinching and subsequent long term tactile allodynia after unilateral hindpaw intraplantar formalin injection (2.5%) or (3) tactile allodynia after unilateral ligation of the L5 and L6 spinal nerves. Rats were treated with the maximum tolerable intrathecal dose of the soluble methylprednisolone sodium succinate (MP) or the particulate methylprednisolone acetate (MPA). Dorsal root ganglia and spinal cords were harvested for immunohistochemistry to assess markers of neuronal damage (ATF3) and glial activation (GFAP, Iba1).

RESULTS

During dose finding, severe generalized allodynia was observed with high intrathecal doses of both MPA and MP in naive rats. MPA had no effect upon tactile allodynia after carrageenan. MP and MPA did not reverse tactile allodynia in the SNL model, and did not reduce flinching in the formalin model. MP and MPA prevented the delayed (7-day) tactile allodynia otherwise observed in the formalin-injected paw. Systemic MP or perineural MP or MPA did not reduce pain-like behaviour in the SNL model. No reduction of neuronal injury (ATF3) in the dorsal root ganglion or astrocyte activation (GFAP) in the spinal dorsal horn with intrathecal MP or MPA was observed. There was a decrease in microglial activation (Iba1) in the spinal dorsal horn with MPA after SNL.

CONCLUSION

Severe generalized allodynia was observed after high intrathecal doses of MP and MPA in naive rats. No acute analgesic effects with intrathecal glucocorticoids were observed in three well established pain models. Only a late antiallodynic effect was present in the formalin model, 7 days after formalin injection and drug treatment.

IMPLICATIONS

Our results do not support use of intrathecal methylprednisolone in the treatment of pain.

Wireless non-invasive continuous respiratory monitoring with FMCW radar: a clinical validation study

Altered respiratory rate is one of the first symptoms of medical conditions that require timely intervention, e.g., sepsis or opioid-induced respiratory depression. To facilitate continuous respiratory rate monitoring on general hospital wards a contactless, non-invasive, prototype monitor was developed using frequency modulated continuous wave radar. We aimed to study whether radar can reliably measure respiratory rate in postoperative patients. In a diagnostic cross-sectional study patients were monitored with the radar and the reference monitor (pneumotachograph during mechanical ventilation and capnography during spontaneous breathing). Eight patients were included; yielding 796 min of observation time during mechanical ventilation and 521 min during spontaneous breathing. After elimination of movement artifacts the bias and 95 % limits of agreement for mechanical ventilation and spontaneous breathing were −0.12 (−1.76 to 1.51) and −0.59 (−5.82 to 4.63) breaths per minute respectively. The radar was able to accurately measure respiratory rate in mechanically ventilated patients, but the accuracy decreased during spontaneous breathing.

Impact of adding therapeutic recommendations to risk assessments from a prediction model for postoperative nausea and vomiting

BACKGROUND

In a large cluster-randomized trial on the impact of a prediction model, presenting the calculated risk of postoperative nausea and vomiting (PONV) on-screen (assistive approach) increased the administration of risk-dependent PONV prophylaxis by anaesthetists. This change in therapeutic decision-making did not improve the patient outcome; that is, the incidence of PONV. The present study aimed to quantify the effects of adding a specific therapeutic recommendation to the predicted risk (directive approach) on PONV prophylaxis decision-making and the incidence of PONV.

METHODS

A prospective before-after study was conducted in 1483 elective surgical inpatients. The before-period included care-as-usual and the after-period included the directive risk-based (intervention) strategy. Risk-dependent effects on the administered number of prophylactic antiemetics and incidence of PONV were analysed by mixed-effects regression analysis.

RESULTS

During the intervention period anaesthetists administered 0.5 [95% confidence intervals (CIs): 0.4-0.6] more antiemetics for patients identified as being at greater risk of PONV. This directive approach led to a reduction in PONV [odds ratio (OR): 0.60, 95% CI: 0.43-0.83], with an even greater reduction in PONV in high-risk patients (OR: 0.45, 95% CI: 0.28-0.72).

CONCLUSIONS

Anaesthetists administered more prophylactic antiemetics when a directive approach was used for risk-tailored intervention compared with care-as-usual. In contrast to the previously studied assistive approach, the increase in PONV prophylaxis now resulted in a lower PONV incidence, particularly in high-risk patients. When one aims for a truly 'PONV-free hospital', a more liberal use of prophylactic antiemetics must be accepted and lower-risk thresholds should be set for the actionable recommendations.

Is "really conscious" sedation with solely an opioid an alternative to every day used sedation regimes for colonoscopies in a teaching hospital? Midazolam/fentanyl, propofol/alfentanil, or alfentanil only for colonoscopy: a randomized trial

BACKGROUND

We investigated the satisfaction of patients and endoscopists and concurrently safety aspects of an "alfentanil only" and two clinically routinely used sedation regimes in patients undergoing colonoscopy in a teaching hospital.

METHODS

One hundred and eighty patients were prospectively randomized in three groups: M (midazolam/fentanyl), A (alfentanil), and P (propofol/alfentanil); M and A were administered by an endoscopy nurse, P by an anesthesia nurse. Interventions, heart rate, saturation, electrocardiogram, noninvasive blood pressure, and expiratory CO₂ were monitored using video assistance. After endoscopy, patients and gastroenterologists completed questionnaires about satisfaction.

RESULTS

A high level of satisfaction was found in all groups, with patients in group P being more satisfied with their sedation experience (median 1.75, p < 0.001). Gastroenterologist satisfaction varied not significantly between the three alternatives. Patients in group A felt less drowsy, could communicate more rapidly than patients in both other groups, and met discharge criteria immediately after the end of the procedure. Respiratory events associated with sedation were observed in 43% patients in group M, 47% in group P, but only 13% in group A (p < 0.001).

CONCLUSIONS

These results suggest that alfentanil could be an alternative for sedation in colonoscopy even in the setting of a teaching hospital. It results in satisfied patients easily taking up information, and recovering rapidly. Although one might expect to observe more respiratory depression with an "opioid only" sedation technique without involvement of anesthesia partners, respiratory events were less frequent than when other methods were used.

The effects of glucocorticoids on neuropathic pain: a review with emphasis on intrathecal methylprednisolone acetate delivery

Methylprednisolone acetate (MPA) has a long history of use in the treatment of sciatic pain and other neuropathic pain syndromes. In several of these syndromes, MPA is administered in the epidural space. On a limited basis, MPA has also been injected intrathecally in patients suffering from postherpetic neuralgia and complex regional pain syndrome. The reports on efficacy of intrathecal administration of MPA in neuropathic pain patients are contradictory, and safety is debated. In this review, we broadly consider mechanisms whereby glucocorticoids exert their action on spinal cascades relevant to the pain arising after nerve injury and inflammation. We then focus on the characteristics of the actions of MPA in pharmacokinetics, efficacy, and safety when administered in the intrathecal space.

Infantile postoperative encephalopathy: perioperative factors as a cause for concern

We report on 6 infants who underwent elective surgery and developed postoperative encephalopathy, which had features most consistent with intraoperative cerebral hypoperfusion. All infants were <48 weeks' postmenstrual age and underwent procedures lasting 120 to 185 minutes. Intraoperative records revealed that most of the measured systolic blood pressure (SBP) values were <60 mm Hg (the threshold for hypotension in awake infants according to the Pediatric Advanced Life Support guidelines) but that only 11% of the measured SBP values were <1 SD of the mean definition of hypotension (<45 mm Hg) as reported in a survey of members of the Society for Pediatric Anesthesia in 2009. Four infants also exhibited prolonged periods of mild hypocapnia (<35 mm Hg). One infant did not receive intraoperative dextrose. All infants developed new-onset seizures within 25 hours of administration of the anesthetic, with a predominant cerebral pathology of supratentorial watershed infarction in the border zone between the anterior, middle, and posterior cerebral arteries. Follow-up of these infants found that 1 died, 1 had profound developmental delays, 1 had minor motor delays, 2 were normal, and 1 was lost to follow-up. Although the precise cause of encephalopathy cannot be determined, it is important to consider the role that SBP hypotension (as well as hypoglycemia, hyperthermia, hyperoxia, and hypocapnia) plays during general anesthesia in young infants in the development of infantile postoperative encephalopathy. Our observations highlight the lack of evidence-based recommendations for the lower limits of adequate SBP and end-tidal carbon dioxide in anesthetized infants.

The Dutch hospital standardised mortality ratio (HSMR) method and cardiac surgery: benchmarking in a national cohort using hospital administration data versus a clinical database

Objective

To compare the accuracy of data from hospital administration databases and a national clinical cardiac surgery database and to compare the performance of the Dutch hospital standardised mortality ratio (HSMR) method and the logistic European System for Cardiac Operative Risk Evaluation, for the purpose of benchmarking of mortality across hospitals.

Methods

Information on all patients undergoing cardiac surgery between 1 January 2007 and 31 December 2010 in 10 centres was extracted from The Netherlands Association for Cardio-Thoracic Surgery database and the Hospital Discharge Registry. The number of cardiac surgery interventions was compared between both databases. The European System for Cardiac Operative Risk Evaluation and hospital standardised mortality ratio models were updated in the study population and compared using the C-statistic, calibration plots and the Brier-score.

Results

The number of cardiac surgery interventions performed could not be assessed using the administrative database as the intervention code was incorrect in 1.4–26.3%, depending on the type of intervention. In 7.3% no intervention code was registered. The updated administrative model was inferior to the updated clinical model with respect to discrimination (c-statistic of 0.77 vs 0.85, p<0.001) and calibration (Brier Score of 2.8% vs 2.6%, p<0.001, maximum score 3.0%). Two average performing hospitals according to the clinical model became outliers when benchmarking was performed using the administrative model.

Conclusions

In cardiac surgery, administrative data are less suitable than clinical data for the purpose of benchmarking. The use of either administrative or clinical risk-adjustment models can affect the outlier status of hospitals. Risk-adjustment models including procedure-specific clinical risk factors are recommended.

Including post-discharge mortality in calculation of hospital standardised mortality ratios: retrospective analysis of hospital episode statistics

OBJECTIVES

To assess the consequences of applying different mortality timeframes on standardised mortality ratios of individual hospitals and, secondarily, to evaluate the association between in-hospital standardised mortality ratios and early post-discharge mortality rate, length of hospital stay, and transfer rate.

DESIGN

Retrospective analysis of routinely collected hospital data to compare observed deaths in 50 diagnostic categories with deaths predicted by a case mix adjustment method.

SETTING

60 Dutch hospitals.

PARTICIPANTS

1 228 815 patients discharged in the period 2008 to 2010.

MAIN OUTCOME MEASURES

In-hospital standardised mortality ratio, 30 days post-admission standardised mortality ratio, and 30 days post-discharge standardised mortality ratio.

RESULTS

Compared with the in-hospital standardised mortality ratio, 33% of the hospitals were categorised differently with the 30 days post-admission standardised mortality ratio and 22% were categorised differently with the 30 days post-discharge standardised mortality ratio. A positive association was found between in-hospital standardised mortality ratio and length of hospital stay (Pearson correlation coefficient 0.33; P=0.01), and an inverse association was found between in-hospital standardised mortality ratio and early post-discharge mortality (Pearson correlation coefficient -0.37; P=0.004).

CONCLUSIONS

Applying different mortality timeframes resulted in differences in standardised mortality ratios and differences in judgment regarding the performance of individual hospitals. Furthermore, associations between in-hospital standardised mortality rates, length of stay, and early post-discharge mortality rates were found. Combining these findings suggests that standardised mortality ratios based on in-hospital mortality are subject to so-called "discharge bias." Hence, early post-discharge mortality should be included in the calculation of standardised mortality ratios.

Near-infrared light to aid peripheral intravenous cannulation in children: a cluster randomised clinical trial of three devices

Intravenous cannulation can be difficult in children. Recently, new devices using near-infrared light to make blood vessels visible have become available. We aimed to evaluate the effectiveness of three such devices in facilitating peripheral intravenous cannulation in children. In this cluster randomised clinical trial, daily operating rooms at a tertiary childrens' hospital were randomised to the use of the VeinViewer®, AccuVein® AV300, VascuLuminator Vision® or to a control group. We included 1913 children between birth and 18 years scheduled for elective surgery. Suitable veins for cannulation were more easily visible with the VeinViewer (307/322 (95.3%)) and AccuVein (239/254 (94.1%)) devices than with VascuLuminator (229/257 (89.1%)) (p = 0.03). However, success at the first attempt was not significantly different among groups, ranging from 73.1% to 75.3% (p = 0.93). We conclude that although vein visibility is enhanced, near-infrared devices do not improve cannulation.

General anesthesia as a possible GABAergic modulator affects visual processing in children

Gamma-Aminobutyric Acid (GABA) inhibitory interneurons play an important role in visual processing, as is revealed by studies administering drugs in human and monkey adults. Investigating this process in children requires different methodologies, due to ethical considerations. The current study aimed to investigate whether a new method, being general anesthesia using Sevoflurane, can be used to trace the effects of GABAergic modulation on visual brain functioning in children. To this aim, visual processing was investigated in children aged 4–12 years who were scheduled for minor urologic procedures under general anesthesia in day-care treatment. In a visual segmentation task, the difference in Event-Related Potential (ERP) response to homogeneous and textured stimuli was investigated. In addition, psychophysical performance on visual acuity and contrast sensitivity were measured. Results were compared between before and shortly after anesthesia. In two additional studies, effects at 1 day after anesthesia and possible effects of task-repetition were investigated. ERP results showed longer latency and lower amplitude of the Texture Negativity (TN) component shortly after compared to before anesthesia. No effects of anesthesia on psychophysical measurements were found. No effects at 1 day after anesthesia or of repetition were revealed either. These results show that GABAergic modulation through general anesthesia affects ERP reflections of visual segmentation in a similar way in children as benzodiazepine does in adults, but that effects are not permanent. This demonstrates that ERP measurement after anesthesia is a successful method to study effects of GABAergic modulation in children.

Determination of moderate-to-severe postoperative pain on the numeric rating scale: a cut-off point analysis applying four different methods

BACKGROUND

Cut-off points (CPs) of the numeric rating scale (NRS 0-10) are regularly used in postoperative pain treatment. However, there is insufficient evidence to identify the optimal CP between mild and moderate pain.

METHODS

A total of 435 patients undergoing general, trauma, or oral and maxillofacial surgery were studied. To determine the optimal CP for pain treatment, four approaches were used: first, patients estimated their tolerable postoperative pain intensity before operation; secondly, 24 h after surgery, they indicated if they would have preferred to receive more analgesics; thirdly, satisfaction with pain treatment was analysed, and fourthly, multivariate analysis was used to calculate the optimal CP for pain intensities in relation to pain-related interference with movement, breathing, sleep, and mood.

RESULTS

The estimated tolerable postoperative pain before operation was median (range) NRS 4.0 (0-10). Patients who would have liked more analgesics reported significantly higher average pain since surgery [median NRS 5.0 (0-9)] compared with those without this request [NRS 3.0 (0-8)]. Patients satisfied with pain treatment reported an average pain intensity of median NRS 3.0 (0-8) compared with less satisfied patients with NRS 5.0 (2-9). Analysis of average postoperative pain in relation to pain-related interference with mood and activity indicated pain categories of NRS 0-2, mild; 3-4, moderate; and 5-10, severe pain.

CONCLUSIONS

Three of the four methods identified a treatment threshold of average pain of NRS≥4. This was considered to identify patients with pain of moderate-to-severe intensity. This cut-off was indentified as the tolerable pain threshold.

Decontamination of the digestive tract and oropharynx in ICU patients

BACKGROUND

Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting.

METHODS

We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance.

RESULTS

A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively.

CONCLUSIONS

In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

[Use of medicines to reduce the risk of postoperative cardiac death: too early for guidelines]

In a review in this journal, Feringa et al. focused on the prevention of cardiovascular complications after non-cardiac surgery. Beta-blockers and statins appear to be the most effective in reducing post-operative mortality due to cardiac events. We have doubts about the external validity of the studies on cardiovascular risks after non-cardiac surgery. A major limitation is that conclusions for all patients have been drawn from relatively small samples with a selection of high-risk patients. Guidelines based upon such studies are 'premature', possibly dangerous and unethical, since the acceptance of such guidelines would preclude large scale studies to confirm the conclusions of the small studies so far performed. Perioperative beta-blockade is only needed in a subgroup of patients with a high-risk cardiac profile.

[Safer operating theatre: easier said than done]

The Netherlands Health Care Inspectorate recently changed its approach to quality of care and patient safety from a reactive to a firmly proactive style. In two reports, the current perioperative processes in Dutch hospitals were scrutinised. Despite a highly-motivated workforce, the inspectorate detected a lack of standardisation, incomplete or inaccessible patient data, poor adherence to hygiene standards and gaps during transfer of care in both the preoperative and intraoperative stages ofsurgery. The inspectorate mandates rapid implementation of various new patient safety approaches, including the use of checklists, 'time-outs' before the start of surgery, double checking of intravenous drugs and improved compliance with hygiene standards, as well as a strict definition of roles and responsibilities of team members. Implementation will require major changes within the processes and culture of operating theatres in Dutch hospitals. Such a change is unlikely to be completed within the short timeframe allowed by the inspectorate.

[Fire and explosion hazard during oxygen use in operating rooms]

In both 2006 and 2007 a large operating room fire occurred in the Netherlands. One patient died as a result of a sudden intense flash fire caused by a leaking oxygen connection. Smaller operating room fires can cause severe burn injuries and inhalation trauma in patients. An oxygen-enriched atmosphere is an important causative factor in most surgical fires. Inflammable substances and ignition sources, such as a diathermic knife or laser, may be present in the operating theatre and environs. The combination of these 3 components (fuel, oxygen and ignition) increases the risk of operation room fires. Prevention and control of this hazard depends on removal of one or more of the 3 components.

Intrathecal low-dose hyperbaric bupivacaine-clonidine combination in outpatient knee arthroscopy: a randomized controlled trial

BACKGROUND

Spinal anesthesia for knee arthroscopy can be produced with a low dose of bupivacaine, but additional intrathecal drugs are often required to lower the risk of failed blocks. We investigated the effect of the addition of clonidine (0, 15 or 30 microg) to 5 mg hyperbaric bupivacaine on the duration of the motor block, analgesic quality and ability to void after the surgery in a randomized controlled trial.

METHODS

Seventy-five patients received spinal anesthesia using either 5 mg hyperbaric bupivacaine (B5C0), 5 mg hyperbaric bupivacaine with 15 microg clonidine (B5C15) or 5 mg hyperbaric bupivacaine with 30 microg clonidine (B5C30). The primary outcome was the duration of the motor block. Secondary outcomes included the time until spontaneous voiding, and the need for additional analgesia or general anesthesia.

RESULTS

The mean time to complete regression of motor block was 70 (+/-43) min in group B5C0. Adding 15 and 30 microg of clonidine increased the motor block duration by 25 [95% confidence interval (CI): 2-48] and 34 (95% CI: 11-57) min, respectively, but resulted in better analgesic quality. The mean time until spontaneous voiding was 177 min in the B5C0 group. This time increased with 18 (95% CI -13 to 49) and 44 (95% CI 15-74) min in group B5C15 and group B5C30, respectively.

CONCLUSION

The addition of 15 microg clonidine to 5 mg of intrathecal hyperbaric bupivacaine prolongs the duration of motor block and improves the quality of the block.

Effects of cardiopulmonary bypass on neurocognitive performance and cytokine release in old and diabetic rats

BACKGROUND

Age and diabetes mellitus have been identified as independent risk factors for cognitive decline after cardiac surgery with cardiopulmonary bypass (CPB). We tested the effects of CPB on cognitive function in aged and diabetic rats utilizing the Morris water maze (MWM).

METHODS

Aged rats (26 months) were randomized into a sham group (cannulation but no CPB, n = 11) and a 90 min CPB group (n = 11). In addition, young rats (n = 14) were made diabetic with streptozotocin 9 weeks before experimentation and randomized to a sham or 90 min CPB group. Cytokine release [interleukin (IL-6)] and short-term MWM performance (days 8-14 after operation) were assessed in all animals. Long-term MWM performance (8 weeks after operation) was assessed in aged rats only.

RESULTS

There were no differences between the aged groups in short-term (P = 0.58) or long-term MWM performances (P = 0.69). The diabetic animals also showed no differences between the sham and CPB groups in MWM performance (P = 0.64). IL-6 assays showed an increased inflammatory response after CPB in the diabetic animals, but not in the elderly groups.

CONCLUSIONS

Ninety minutes of normothermic CPB had no deleterious effect on neurocognitive outcome in elderly or chronically diabetic animals, suggesting that CPB in itself is not a sufficient stressor of the rat central nervous system.

Predicting postherpetic neuralgia in elderly primary care patients with herpes zoster: prospective prognostic study

Postherpetic neuralgia (PHN) is the most frequent complication of herpes zoster (HZ) and difficult to treat. Timely identification of high-risk HZ-patients enables physicians to focus on PHN prevention. To assess which simple to measure factors are independent predictors of PHN, and whether psychosocial and serological/virological parameters have additional predictive value, a prospective cohort study in primary care was conducted. We included 598 elderly (>50 years) consecutive patients with acute HZ (rash <7 days) below sixth cervical dermatome. At baseline demographic, clinical (e.g., duration and severity of pain and rash), psychological (Pain Cognition List [PCL] and Spielberger's Anxiety Inventory), serological (VZV-antibodies) and virological (viremia presence) variables were measured. Blood tests were performed in a random subset of 218 patients. Primary outcome was significant pain (VAS >30 on 0-100 scale) after three months. The final prediction model obtained from multivariable logistic regression was (internally) validated using bootstrapping techniques, and adjusted for optimism. Forty-six (7.7%) patients developed PHN. Independent predictors were age (odds ratio [OR]=1.08 per year), acute pain severity (OR=1.02 per unit), presence of severe rash (OR=2.31), and rash duration before consultation (OR=0.78 per day): area under receiver-operating-characteristic curve [ROC area]=0.77 (95% CI: 0.71-0.82). Of the five PCL scores, only factor V ('trust in healthcare') was an additional predictor (OR=1.01 per unit), though it increased the ROC area with only 0.01 to 0.78. The Spielberger's anxiety scores and serological and virological variables were no additional predictors. Thus, four simple variables can help physicians to timely identify elderly HZ-patients at risk of PHN.

[Perioperative use of psychotropic drugs; advice based on casuistic and 'expert-based medicine']

Little scientific evidence is available on the continuation of psychotropic drugs in the perioperative period. Clinicians often have to rely on case reports and small case series. However, case reports of rare events, such as life-threatening interactions between psychotropic drugs and anaesthetics, do not provide reliable data on the frequency of such events and may lead to a rather defensive approach. Recommendations were published recently based on expert opinion from a multidisciplinary group. This proposal could be used for the development of an official, evidence-based guideline on the perioperative use of psychotropic drugs. The quality of such a guideline would be improved by prospective cohort studies that compare events in patients who discontinue psychotropic medication with those in patients who continue medication for fear of severe withdrawal symptoms.

[Treatment of patients with herpes zoster by epidural injection of steroids and local anaesthetics: less pain after 1 month, but no effect on long-term postherpetic neuralgia--a randomised trial]

OBJECTIVE

To assess the effectiveness of a single epidural injection of steroids and local anaesthetics, as a supplement to the standard treatment, for the prevention ofpostherpetic neuralgia in older patients with herpes zoster.

DESIGN

Open randomised trial.

METHOD

In the period September 2001-February 2004, 598 patients, aged > 50 years, with acute herpes zoster (rash for < 7 days) below dermatome C6, were randomly assigned to receive either standard therapy (oral antiviral agents and analgesics) alone or standard therapy plus an additional single epidural injection of 80 mg methylprednisolone and 10 mg bupivacaine. The primary endpoint was the proportion of patients with zoster-associated pain one month after inclusion. The presence and severity of zoster-associated pain at other time points were secondary endpoints.

RESULTS

At one month, pain was reported by 137 (48%) patients in the injection group versus 164 (58%) in the control group (relative risk; RR: 0.83; 95% CI: 0.71-0.97; p = 0.02). After three months, these values were 58 (21%) and 63 (24%), respectively (RR: 0.89; 95% CI: 0.65-1-21; p = 0.47), and at 6 months: 39 (15%) and 44 (17%) (RR: 0.85; 95% CI: 0.57-1-13; p = 0.43). No subgroups were detectable in which the relative risk for pain at one month after inclusion substantially differed from the overall estimate. At one month, the median severity of pain in the injection group was 2 (on a 100-points scale) versus 6 in the control group (p = 0.02). At later follow-up, there was no longer any statistically significant difference in the severity of pain between the two groups. No patient had major adverse events related to the epidural injection.

CONCLUSION

A single epidural injection of steroids and local anaesthetics in the acute phase of herpes zoster resulted in a modest decrease in zoster-associated pain in the first month. This treatment did not, however, prevent long-term postherpetic neuralgia.

The impact of chronic pain patients' psychotropic drug knowledge and warning labels on the decision whether to drive a car or not

OBJECTIVE

The attitudes of patients towards driving a car while taking medication with psychotropic side effects is unclear. A growing number of patients use these psychotropic medicines on a daily basis, and this may interfere with their ability to drive a car.

METHODS

By means of a survey, we examined attitudes towards driving while using psychotropic medicinal drugs and the effect of warning labels on the decision whether to drive a car or not in patients with chronic pain.

RESULTS

Fifty-eight of 100 patients possessing a driver's license used psychotropic medication. Despite warning labels affixed on the packages that these drugs might impair driving ability, the majority (71%) of these patients continued driving a car. A point of concern is that 40% of these patients reported not to be more cautious in traffic after taking psychotropic drugs.

CONCLUSION

The results of this survey indicate that drug warning labels applied by Dutch pharmacies do not significantly change attitudes towards driving a car in patients taking medicinal drugs with psychotropic side effects. Future road-safety campaigns should pay more attention to the impairing effects of psychotropic drugs on driving.

The effect of addition of intrathecal clonidine to hyperbaric bupivacaine on postoperative pain and morphine requirements after Caesarean section: a randomized controlled trial

BACKGROUND

Intrathecal clonidine prolongs spinal anaesthesia. We investigated the effect of the addition of clonidine (75 microg) to hyperbaric bupivacaine on postoperative morphine consumption after Caesarean section in a randomized controlled double-blind trial.

METHODS

A group of 106 women received spinal anaesthesia using either bupivacaine 0.5% (2.2 ml) heavy with 0.5 ml normal saline 0.9% (B) or bupivacaine 0.5% (2.2 ml) heavy with clonidine (75 microg) in 0.5 ml normal saline 0.9% (BC). The primary outcome was the total morphine consumption in the first 24 h after surgery. Secondary outcomes were the duration of postoperative analgesia, postoperative pain scores, the need for alfentanil during surgery, block regression, clonidine side-effects and morphine side-effects.

RESULTS

Total morphine consumption was similar in both study groups. The mean time to the first analgesic request in the BC group was 129 (SD 13.8) min, compared with 55 (14.2) min in the B group [mean difference (95% CI) -75 (-106 to -44) min]. In the BC group 22 (42%) patients had a complete motor block 1 h after surgery compared with 4 (8%) patients in the B group [RR (95% CI) 0.18 (0.07-0.49)]. Side-effects of intrathecal clonidine were not detected.

CONCLUSIONS

The addition of clonidine (75 microg) to hyperbaric bupivacaine prolongs spinal anaesthesia after Caesarean section and improves early analgesia, but does not reduce the postoperative morphine consumption during the first 24 h. No clinically relevant maternal or neonatal side-effects were detected.

Electrocardiographic changes predicting sudden death in propofol-related infusion syndrome

BACKGROUND

The occurrence of metabolic acidosis, rhabdomyolysis, hyperkalemia, and sudden cardiac death after long-term, high-dose propofol infusion has been referred to as propofol infusion syndrome (PRIS).

OBJECTIVES

The purpose of this study was to explore the ECG abnormalities observed in a patient with PRIS in order to identify possible pathophysiologic mechanisms of the syndrome.

METHODS

ECG changes in the index case were characterized by down-sloping ST-segment elevation in precordial leads V1 to V3 (Brugada-like ECG pattern). We subsequently assessed the relationship between this ECG pattern and the propofol infusion rate, the development of arrhythmias, and the occurrence of sudden death in a previously described cohort of 67 head-injured patients, seven of whom had been identified as having PRIS.

RESULTS

Six of the PRIS patients developed the ECG pattern of ST-segment elevation in leads V1 to V3 and died within hours of irrecoverable electrical storm. This ECG pattern was the first aberration recorded hours before the death of these patients. ECGs that were available for 30 of 60 unaffected patients exhibited a normal pattern. None of the 60 patients developed ventricular arrhythmias.

CONCLUSION

Our findings indicate that development of an acquired Brugada-like ECG pattern in severely head-injured patients is a sign of cardiac electrical instability that predicts imminent cardiac death. Future studies will determine whether such an ECG pattern also predicts imminent cardiac arrhythmia in other patient populations.

Effect of chronic nonmalignant pain on highway driving performance

Most pain patients are treated in an outpatient setting and are engaged in daily activities including driving. Since several studies showed that cognitive functioning may be impaired in chronic nonmalignant pain, the question arises whether or not chronic nonmalignant pain affects driving performance. Therefore, the objective of the present study was to determine the effects of chronic nonmalignant pain on actual highway driving performance during normal traffic. Fourteen patients with chronic nonmalignant pain and 14 healthy controls, matched on age, educational level, and driving experience, participated in the study. Participants performed a standardized on-the-road driving test during normal traffic, on a primary highway. The primary parameter of the driving test is the Standard Deviation of Lateral Position (SDLP). In addition, driving-related skills (tracking, divided attention, and memory) were examined in the laboratory. Subjective assessments, such as pain intensity, and subjective driving quality, were rated on visual analogue scales. The results demonstrated that a subset of chronic nonmalignant pain patients had SDLPs that were higher than the matched healthy controls, indicating worse highway driving performance. Overall, there was a statistically significant difference in highway driving performance between the groups. Further, chronic nonmalignant pain patients rated their subjective driving quality to be normal, although their ratings were significantly lower than those of the healthy controls. No significant effects were found on the laboratory tests.

Processing capacity in chronic pain patients: a visual event-related potentials study

Chronic pain may impair performance on attentional processing capacity tasks. In the present study, event-related potentials were recorded to examine whether pain patients show performance decrements on attentional processing capacity tasks due to shared resources by pain and attention or, alternatively, due to deficits in allocating attentional resources during pain. Fourteen chronic pain patients and thirty age and education matched healthy controls were investigated. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a difficult condition, while task-irrelevant visual probes were presented. These probe-elicited P3 amplitudes were assumed to provide the most pure estimate of processing capacity since they are relatively free from target-related processes. Event-related potentials were recorded from the midline electrodes Fz, Cz, Pz, and Oz. For the behavioral measures, it was found that pain patients maintained a different speed-accuracy tradeoff. Pain patients showed faster reaction time responses and higher error rates compared to controls. No significant differences were found between pain patients and controls on the primary task. Pain patients differed from controls with respect to amplitudes elicited by task-irrelevant probe stimuli. For healthy controls, the expected decreased amplitude was found for probe stimuli in the difficult compared to the easy task. In contrast, the pain patients did not show decreased probe amplitudes with increasing task load. The data may imply that allocation of attentional resources is deficient in pain patients, instead of attentional capacity.

Pre-operative detection of valvular heart disease by anaesthetists

We prospectively estimated the prevalence of heart murmurs in 2522 consecutive adult non-cardiac surgery patients during pre-operative evaluation. Factors that contribute to the detection of a heart murmur were identified, and echocardiography was used to evaluate to what extent a murmur reflected presence of valvular heart disease. A cardiac murmur was detected in 106 patients (prevalence 4.2%, 95% CI: 3.5-5.1%). Multivariable logistic regression analyses showed that age and general physical impression were independently associated with detecting a murmur (p-values < 0.01). In 83 (79%) of the patients with a murmur, an echocardiographic diagnosis was available: 39% had aortic valve abnormalities, 24% had mitral valve regurgitation, 7% had other valvular heart disease and 30% did not have any abnormality. Thus, 58 of the 83 patients had valvular heart disease (positive predictive value using routine cardiac auscultation for diagnosing VHD: 70%, 95% CI: 59-79%). Murmurs in patients younger than 40 years never reflected valvular heart disease. Pre-operative cardiac auscultation seems only reasonable in patients aged 40 years or older. Subsequent echocardiography in these selected patients is necessary.

The PINE study of epidural steroids and local anaesthetics to prevent postherpetic neuralgia: a randomised controlled trial

BACKGROUND

Postherpetic neuralgia is the most frequent complication of herpes zoster. Treatment of this neuropathic pain syndrome is difficult and often disappointing. We assessed the effectiveness of a single epidural injection of steroids and local anaesthetics for prevention of postherpetic neuralgia in older patients with herpes zoster.

METHODS

We randomly assigned 598 patients older than 50 years, with acute herpes zoster (rash <7 days) below dermatome C6, to receive either standard therapy (oral antivirals and analgesics) or standard therapy with one additional epidural injection of 80 mg methylprednisolone acetate and 10 mg bupivacaine. The primary endpoint was the proportion of patients with zoster-associated pain 1 month after inclusion. Analyses were by intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN32866390.

FINDINGS

At 1 month, 137 (48%) patients in the epidural group reported pain compared with 164 (58%) in the control group (relative risk [RR] 0.83, 95% CI 0.71-0.97, p=0.02). After 3 months these values were 58 (21%) and 63 (24%) respectively (0.89, 0.65-1.21, p=0.47) and, at 6 months, 39 (15%) and 44 (17%; 0.85, 0.57-1.13, p=0.43). We detected no subgroups in which the relative risk for pain 1 month after inclusion substantially differed from the overall estimate. No patient had major adverse events related to epidural injection.

INTERPRETATION

A single epidural injection of steroids and local anaesthetics in the acute phase of herpes zoster has a modest effect in reducing zoster-associated pain for 1 month. This treatment is not effective for prevention of long-term postherpetic neuralgia.

Acute and subchronic effects of amitriptyline on processing capacity in neuropathic pain patients using visual event-related potentials: preliminary findings

RATIONALE

Little is known about the effects of low doses of amitriptyline, prescribed in the treatment of neuropathic pain, on attentional processing capacity.

OBJECTIVES

Changes due to amitriptyline treatment on attentional processing capacity were investigated on behavioral measures and event-related brain potentials (ERPs) in six patients with neuropathic pain.

MATERIALS AND METHODS

Patients were treated for 15 consecutive days with 25 mg nocturnally administered amitriptyline or placebo in a double-blind crossover randomized design. Measurements were carried out on day 1 and day 15 of each treatment period. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a hard condition, while task-irrelevant visual probes were presented. During task performance, ERPs were measured from the midline electrodes Fz, Cz, Pz, and Oz.

RESULTS

Amitriptyline increased reaction times (RTs) after acute but not after subchronic administration. ERP analyses showed that P3 amplitudes to the task stimuli were not affected by amitriptyline in either treatment phase. Moreover, P3 amplitudes to the probes were increased in the easy compared to the hard task condition after subchronic amitriptyline treatment, indicating beneficial effects of repeated amitriptyline administration. In contrast, acute amitriptyline administration did reduce an earlier visual evoked potential, N1, preceding the P3 component.

CONCLUSIONS

The results suggest that amitriptyline, even at low dosages of 25 mg, affects performance after acute administration in chronic neuropathic pain patients. After 2 weeks of treatment, performance appears to be unaffected. No deficits in processing capacity due to amitriptyline treatment were found.

The incidence of cognitive decline after (not) undergoing coronary artery bypass grafting: the impact of a controlled definition

BACKGROUND

After coronary artery bypass grafting (CABG), 20-30% of patients are reported to suffer from cognitive decline. Studies reporting these high incidences, however, have not included an appropriate control group.

METHODS

We repeatedly administered a series of neuropsychological tests to 112 healthy middle-aged volunteers not undergoing surgery, and applied two widely used definitions of cognitive decline to their test results. In addition, we re-analysed the neuropsychological test data of 281 CABG patients with a definition of cognitive decline that takes into account the natural variability of test performance that was found in the volunteers.

RESULTS

Three months after their first assessment, 14-28% of the volunteers suffered from cognitive decline according to the definitions of cognitive decline after CABG. Using the controlled definition of cognitive decline that takes the natural variability in test performance into account, we found that only 7.7% of the CABG patients suffered from cognitive decline at 3 months after their operation.

CONCLUSION

These data suggest that the incidence of cognitive dysfunction after CABG has previously been greatly overestimated.

Do herpes zoster patients receive antivirals? A Dutch National Survey in General Practice

BACKGROUND

The main complications of herpes zoster (HZ) are postherpetic neuralgia and, in case of HZ ophthalmicus, eye disorders. Antiviral treatment may modify the course of disease and reduce the risk of complications.

OBJECTIVE

To assess which doctors' and patients' characteristics were related to prescription of antiviral therapy for HZ.

METHODS

Ninety general practices (358 008 patients) in The Netherlands registered all patient contacts in a database for one year as part of the Second Dutch National Survey of General Practice. The present study used ICPC code S70 to search that database for patients with a new diagnosis of HZ. The full-text medical records of the selected patients were then reviewed and the potential determinants for the prescription of antiviral drugs (including characteristics of patients, GPs, and practices) analysed using multilevel logistic regression modelling.

RESULTS

Of the 1129 patients diagnosed with HZ (incidence 3.2/1000 patients/year), 22.5% received antiviral drugs. Independent determinants for prescription of antiviral therapy were age [45-54 years: adjusted odds ratio (OR) 2.9 (95% CI 1.6-5.0); 55-64 years: OR 4.2 (95% CI 2.4-7.6); 65-74 years: OR 5.1 (95% CI 2.7-9.6); > or =75 years: OR 8.1 (95% CI 4.4-15.1)], ophthalmic localisation of the shingles (OR 3.2, 95% CI 1.6-6.7), and the presence of asthma/COPD (OR 1.6, 95% CI 1.0-2.6). GPs who reported to strongly adhere to professional guidelines prescribe more frequently antiviral drugs (OR 1.9, 95% CI 1.2-3.1).

CONCLUSIONS

A minority of HZ patients were prescribed antiviral treatment. Increasing age, ophthalmic localisation, presence of asthma/COPD, and adherence to professional guidelines were factors favouring prescription. More information on the determinants of GPs' treatment decisions is necessary for successful implementation of HZ guidelines.

Jugular bulb desaturation during coronary artery surgery: a comparison of off-pump and on-pump procedures † †Presented in part at the annual Outcomes Meeting at Key West, FL, USA, 2001. ‡ ‡This article is accompanied by the Editorial

BACKGROUND

Conventional coronary artery bypass surgery has been associated with cerebral injury attributed to cardiopulmonary bypass (CPB) and surgical manipulation of the ascending aorta. Off-pump coronary artery surgery avoids these factors and could prevent cerebral injury. However, moving the heart from its natural position affects the circulation and could compromise cerebral oxygenation and perfusion. We set out to compare episodes of poor global cerebral oxygenation, defined as a jugular bulb saturation less than 50%, between patients randomized to off-pump or (conventional) on-pump coronary artery surgery.

METHODS

One hundred and eighty-seven patients were assigned randomly to off-pump or on-pump coronary artery surgery. Oxygen saturation in the jugular bulb (SjO2) was measured during revascularization of the three main coronary vessels in the off-pump group, and at the start of CPB, before rewarming, and after rewarming in the on-pump group. We compared samples with jugular bulb with desaturation (SjO2) < or = 50%) between treatment groups.

RESULTS

One hundred and seventy-five patients (81 in the off-pump group [93%] and 94 in the on-pump group [94%]) had complete jugular oxygen saturation data. Thirty-nine patients in the off-pump group (48%) and 25 patients in the on-pump group (27%) had one or more samples with desaturation during revascularization or CPB (odds ratio after adjustment for other factors, 0.39; 95% confidence interval, 0.21-0.73, P<0.01).

CONCLUSION

Jugular bulb desaturation occurs more frequently during off-pump coronary artery surgery than during conventional coronary artery surgery.

Assessing the applicability of scoring systems for predicting postoperative nausea and vomiting

We have validated two scoring systems for predicting postoperative nausea and vomiting, derived by Apfel et al. and Koivuranta et al. from 1388 adult inpatients undergoing a wide range of surgical procedures. The predictive accuracy of the scoring systems was evaluated in terms of the ability to discriminate between patients with and without postoperative nausea and vomiting (discrimination) and agreement between observed and predicted outcomes (calibration). Discrimination and calibration were less than expected based on previous reports, with both scoring systems providing risk predictions that were too extreme. The area under the ROC curve was 0.63 for Apfel et al.'s scoring system and 0.66 for Koivuranta et al.'s scoring system. Neither of the scoring systems provided a risk threshold for administering anti-emetic prophylaxis that yielded satisfying results in terms of predictive values, sensitivity and specificity. Hence, in their original forms, the scoring systems do not guarantee accurate prediction of the risk of postoperative nausea and vomiting in other patient populations. Koivuranta et al.'s scoring system appears to be more robust across different populations.

Cerebral hemodynamic responses to blood pressure manipulation in severely head-injured patients in the presence or absence of intracranial hypertension

The management of cerebral perfusion pressure (CPP) remains a controversial issue in the critical care of severely head-injured patients. Recently, it has been proposed that the state of cerebrovascular autoregulation should determine individual CPP targets. To find optimal perfusion pressure, we pharmacologically manipulated CPP in a range of 51 mm Hg (median; 25th-75th percentile, 48-53 mm Hg) to 108 mm Hg (102-112 mm Hg) on Days 0, 1, and 2 after severe head injury in 13 patients and studied the effects on intracranial pressure (ICP), autoregulation capacity, and brain tissue partial pressure of oxygen. Autoregulation was expressed as a static rate of regulation for 5-mm Hg CPP intervals based on middle cerebral artery flow velocity. When ICP was normal (26 occasions), there were no major changes in the measured variables when CPP was altered from a baseline level of 78 mm Hg (74-83 mm Hg), indicating that the brain was within autoregulation limits. Conversely, when intracranial hypertension was present (11 occasions), CPP reduction to less than 77 mm Hg (73-82 mm Hg) further increased ICP, decreased the static rate of regulation, and decreased brain tissue partial pressure of oxygen, whereas a CPP increase improved these variables, indicating that the brain was operating at the lower limit of autoregulation. We conclude that daily trial manipulation of arterial blood pressure over a wide range can provide information that may be used to optimize CPP management.

The accuracy of trained nurses in pre-operative health assessment: results of the OPEN study

We quantified the accuracy of trained nurses to correctly assess the pre-operative health status of surgical patients as compared to anaesthetists. The study included 4540 adult surgical patients. Patients' health status was first assessed by the nurse and subsequently by the anaesthetist. Both needed to answer the question: 'is this patient ready for surgery without additional work-up, Yes/No?' (primary outcome). The secondary outcome was the time required to complete the assessment. Anaesthetists and nurses were blinded for each other's results. The anaesthetists' result was the reference standard. In 87% of the patients, the classifications by nurses and anaesthetists were similar. The sensitivity of the nurses' assessment was 83% (95% CI: 79-87%) and the specificity 87% (95% CI: 86-88%). In 1.3% (95% CI: 1.0-1.6%) of patients, nurses classified patients as 'ready' whereas anaesthetists did not. Nurses required 1.85 (95% CI: 1.80-1.90) times longer than anaesthetists. By allowing nurses to serve as a diagnostic filter to identify the subgroup of patients who may safely undergo surgery without further diagnostic workup or optimisation, anaesthetists can focus on patients who require additional attention before surgery.

Association between early and three month cognitive outcome after off-pump and on-pump coronary bypass surgery

OBJECTIVE

To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery.

DESIGN

Randomised trial with an additional prediction study within the two randomised groups.

SETTING

Three centres for heart surgery in the Netherlands.

PATIENTS

281 patients, mean age 61 years.

INTERVENTIONS

Participants were randomly assigned to off-pump or on-pump coronary bypass surgery.

MAIN OUTCOME MEASURES

Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months.

RESULTS

Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three months. This association was stronger in on-pump patients (odds ratio (OR) 5.24, p < 0.01) than in off-pump patients (OR 1.80, p = 0.23). Early decline was present in 54 patients (49%) after off-pump surgery and 61 patients (57%) after on-pump surgery (OR 0.73, p = 0.25).

CONCLUSIONS

In patients undergoing first time coronary bypass surgery, early cognitive decline predicts cognitive outcome after three months. Early cognitive decline is not significantly influenced by the use of cardiopulmonary bypass.

Association between early and three month cognitive outcome after off-pump and on-pump coronary bypass surgery

OBJECTIVE

To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery.

DESIGN

Randomised trial with an additional prediction study within the two randomised groups.

SETTING

Three centres for heart surgery in the Netherlands.

PATIENTS

281 patients, mean age 61 years.

INTERVENTIONS

Participants were randomly assigned to off-pump or on-pump coronary bypass surgery.

MAIN OUTCOME MEASURES

Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months.

RESULTS

Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three months. This association was stronger in on-pump patients (odds ratio (OR) 5.24, p < 0.01) than in off-pump patients (OR 1.80, p = 0.23). Early decline was present in 54 patients (49%) after off-pump surgery and 61 patients (57%) after on-pump surgery (OR 0.73, p = 0.25).

CONCLUSIONS

In patients undergoing first time coronary bypass surgery, early cognitive decline predicts cognitive outcome after three months. Early cognitive decline is not significantly influenced by the use of cardiopulmonary bypass.

The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390]

BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life. The results of PHN treatment are rather disappointing. Epidural injection of local anaesthetics and steroids in the acute phase of HZ is a promising therapy for the prevention of PHN. Since randomised trials on the effectiveness of this intervention are lacking, the PINE (Prevention by epidural Injection of postherpetic Neuralgia in the Elderly) study was set up. The PINE study compares the effectiveness and cost-effectiveness of a single epidural injection of local anaesthetics and steroids during the acute phase of HZ with that of care-as-usual (i.e. antivirals and analgesics) in preventing PHN in elderly patients. METHODS / DESIGN: The PINE study is an open, multicenter clinical trial in which 550 elderly (age >/= 50 yr.) patients who consult their general practitioner in the acute phase of HZ (rash < 7 days) are randomised to one of the treatment groups. The primary clinical endpoint is the presence of HZ-related pain one month after the onset of the rash. Secondary endpoints include duration and severity of pain, re-interventions aiming to treat the existing pain, side effects, quality of life, and cost-effectiveness. CONCLUSION: The PINE study is aimed to quantify the (cost-) effectiveness of a single epidural injection during the acute phase of HZ on the prevention of PHN.