The Patient's perspective: A review of the results from a radiotherapy patient experience survey in the North-West of England.

INTRODUCTION: A patient experience survey was undertaken for patients completing radiotherapy at the three Northwest of England Radiotherapy Providers. METHODS: A previously reported National Radiotherapy Patient Experience Survey was adapted and undertaken in the Northwest of England. Quantitative data was analysed to establish trends. Frequency distribution was applied to appraise the number of participants selecting each of the pre-determined responses. Thematic analysis of free text responses was conducted. RESULTS: The questionnaire received 653 responses from the 3 providers across seven departments. Thematic analysis revealed 3 themes; logistics, information and operational. CONCLUSION: The results indicate that the majority of patients are satisfied with their treatment and care. Patients' responses indicate areas for improvements. Expectancy theory states that an individual's satisfaction is related to the difference between expected service and the service received. Consequently, when reviewing services and developing improvement it is important to understand patients' expectations. This regional survey starts to capture what people receiving radiotherapy expect from the service and the professionals delivering their treatment. IMPLICATIONS FOR PRACTICE: This survey responses make a case for reviewing the information provision pre and post radiotherapy. This includes clarifying the understanding of consent for treatment including the intended benefits and potential late effects. There is an argument to offer information sessions prior to radiotherapy to achieve more relaxed and informed patients. A recommendation from this work is for the radiotherapy community undertake a national radiotherapy patient experience survey, facilitated via the 11 Radiotherapy ODNs. A national radiotherapy survey has multiple benefits to inform improvements in practice. This includes benchmarking services against national averages. This approach is aligned with the principles of the service specification in terms of reducing variation and increasing quality.

Point Absorber Limits to Future Gravitational-Wave Detectors.

High-quality optical resonant cavities require low optical loss, typically on the scale of parts per million. However, unintended micron-scale contaminants on the resonator mirrors that absorb the light circulating in the cavity can deform the surface thermoelastically and thus increase losses by scattering light out of the resonant mode. The point absorber effect is a limiting factor in some high-power cavity experiments, for example, the Advanced LIGO gravitational-wave detector. In this Letter, we present a general approach to the point absorber effect from first principles and simulate its contribution to the increased scattering. The achievable circulating power in current and future gravitational-wave detectors is calculated statistically given different point absorber configurations. Our formulation is further confirmed experimentally in comparison with the scattered power in the arm cavity of Advanced LIGO measured by in situ photodiodes. The understanding presented here provides an important tool in the global effort to design future gravitational-wave detectors that support high optical power and thus reduce quantum noise.

Experimental and numerical study of interlock requirements for high-power EYDFAs.

In this work, we studied the interlock requirements in a seed failure scenario for Er3+:Yb3+ doped fiber amplifiers (EYDFAs) pumped with high intensities in the MWcm-2 range at 9XX nm. We fed a time-dependent FEM-tool with the data from backwards directed amplified spontaneous emission (ASE) transients of different commercially available core-pumped single-mode fibers. In the FEM-tool, the Er3+:Yb3+ system is defined as a bi-directional energy transfer process and described by the corresponding rate equations. The power evolution of the pump, seed, and ASE signal is computed by differential equations taking into account the transient population densities of the relevant energy levels. With the model, we computed the temporal evolution of the corresponding energy levels after a seeder failure to take place within tens to hundreds of µs and calculated the associated gain. The fibers under test provide a critical total gain of 30 dB after ∼ 80 µs within the Yb3+ band and after ∼300 µs within the Er3+ band. This time decreases with increasing pump power and doping concentration. The results can be extrapolated to high-power cladding-pumped EYDFAs to meet the challenging requirements of engineering-level systems.

The impact of cardiopulmonary bypass on selenium status, thyroid function, and oxidative defense in children.

Selenium has important functions for oxidative defense and thyroid hormone metabolism. Selenium-dependent enzymes include 5'-iodothyronine deiodinase and glutathione peroxidase (GPX). The objective of this study was to investigate the relationship between plasma selenium, GPX activity, and thyroid hormone status in pediatric cardiac surgical patients. Plasma concentrations of selenium, free triiodothyronine (fT3), free thyroxin (fT4), and c-reactive protein as well as plasma activity of GPX were prospectively evaluated at anesthetic induction and 48 hours postoperatively in 59 children requiring cardiopulmonary bypass (CPB). GPX was measured at additional time points at 6, 12, and 24 hours postoperatively. There was a significant reduction in the plasma selenium concentration after cardiopulmonary bypass with obtained median measurements of 0.61 micromol/L (induction) and 0.51 micromol/L (48 hours postoperatively). The fT3/fT4 ratio decreased significantly from 0.28 at anesthetic induction to 0.22 at 48 hours postoperatively. There were no significant changes of GPX activity. 48 hours fT3 concentration, fT3/fT4 ratio, and selenium concentration were significantly negatively correlated with the time spent in intensive care. The concentration of plasma selenium in children undergoing cardiopulmonary bypass significantly decreases, resulting in diminished deiodinase activity, and a subsequent reduction in the conversion of T4 to T3.

Post-cardiotomy mechanical circulatory support using a conventional bypass circuit in children.

OBJECTIVE: Mechanical circulatory support (MCS) is increasingly used after cardiotomy in children when conventional medical treatment fails. Poor overall survival and long-term outcome have been reported. We report our experience of post-cardiotomy MCS using a conventional bypass circuit. METHODS: Over a 4 year and 6 month period 10 patients, with a median age of 16 days (range 5 days to 16 years) required MCS. Eight patients required support for failure to wean from cardiopulmonary bypass during primary correction. Two patients required support for cardiac arrest or poor cardiac output in the postoperative period. RESULTS: The median duration of support was 43 h (range 26-146 h). Seven hospital survivors were alive and well at median follow-up of 18 months (range 4-36 months). One patient could not be weaned off support. Two more patients died after successful weaning from support. Complications in nine patients who could be weaned off support included renal failure (n=6), cerebrovascular events (n=3) and mediastinitis (n=2). CONCLUSIONS: Overall long-term survival (70%) and quality of recovery is usually good even though initial mortality and complication rates may be high. We think that post cardiotomy mechanical circulatory bypass using a conventional bypass circuit can offer a favourable outcome to selected patients.

Arterial to end-tidal carbon dioxide tension difference in children with congenital heart disease.

In children with congenital cyanotic heart disease, right-to-left intracardiac shunting causes an obligatory difference between arterial and end-tidal carbon dioxide tension (PaCO2-PE'CO2) as venous blood, rich in carbon dioxide, is added to the arterial circulation. This obligatory PaCO2-PE'CO2 difference, which can be predicted from knowledge of oxygen saturation, haemoglobin concentration and PaCO2, increases as oxygen saturation decreases, most markedly when the haemoglobin concentration is high. A second possible cause of the PaCO2-PE'CO2 difference is the effect of pulmonary hypoperfusion caused by the shunt. We studied 60 children undergoing cardiac surgery and compared the predicted the PaCO2-PE'CO2 difference with measured values to investigate the extent to which additional factors influence the clinically observed PaCO2-PE'CO2. In many children, observed values were much greater than predicted, which is compatible with some degree of pulmonary hypoperfusion. However, this was not felt to represent the complete picture in all patients. Another cause of ventilation-perfusion mismatch was suspected in those children who showed a considerable improvement in oxygen saturation during ventilation with an increased FIO2. We believe that pulmonary congestion caused by large left-to-right shunts may further increase the PaCO2-PE'CO2 difference.

A randomized controlled trial of the antiemetic effect of three doses of ondansetron after strabismus surgery in children.

METHODS: One hundred and thirty-one healthy children, aged 31-152 months, undergoing strabismus surgery under general anaesthesia, were randomly allocated to one of four groups: group A received 0.04 mg.kg-1 ( identical with 1 mg.m-2) of ondansetron, group B 0.1 mg.kg-1 ( identical with 2.5 mg.m-2), group C 0.2 mg.kg-1 ( identical with 5 mg.m-2) and group D placebo, given intravenously following induction of anaesthesia. Morphine 0.15 mg.kg-1 was given intravenously, intraoperatively, to provide postoperative analgesia. Hourly records of emetic episodes were made for 24 h. RESULTS: A considerably higher proportion of children suffered emesis in the placebo group compared to the active treatment groups taken together, during the first 8 h of postoperative care (76% vs. 45%, P=0.002). During the first 8 h, only 25% of those in treatment group C suffered emesis, the number-needed-to-treat was 3. There was a statistically significant decrease in the chance of vomiting with increasing dose of ondansetron (P=0.03). By 24 h, the difference in the rate of emesis was less marked but still statistically significant (90% vs. 69%, P=0.03). CONCLUSION: Overall, children given ondansetron had less than one-half the risk of vomiting compared to those given placebo (hazard ratio 0.46, 95% confidence interval 0.29-0.74). The mean number of emetic episodes declined from 2.73 in the placebo group to 1.92 in treatment group C. There was no difference in the incidence of side-effects between groups.

Enoximone pharmacokinetics in infants.

Enoximone and enoximone sulphoxide concentrations were measured in plasma of 20 infants, median age 6.0 (range 0.6-49.7) weeks, during and after prolonged continuous infusions. Patients were given enoximone 1 mg kg-1 and an infusion at 10 micrograms kg-1 min-1 just before being weaned from cardiopulmonary bypass (CPB). The infusion was stopped when clinically indicated, after a median 97 (range 24-572) h. Arterial blood samples were taken 30 min and 12 h after CPB, every 24 h during the infusion, and then 2, 4, 8, 12 and 24 h after the infusion was stopped. Pharmacokinetic non-compartmental analysis was performed using TOPFIT software. Fourteen patients who retained normal hepatic function had a median (95% confidence intervals) clearance of 9.7 (6.3-14.1) ml min-1 kg-1, elimination half-life of 5.2 (2.4-6.8) h and a volume of distribution of 3.6 (2.0-5.7) litre kg-1. The six patients with significant hepatic dysfunction had a lower clearance, 5.7 (2.4-14.5) ml min-1 kg-1, and significantly longer elimination half-life, 7.6 (6.5-10.9) h (P = 0.02). Enoximone sulphoxide elimination half-life was significantly prolonged in three patients with renal dysfunction, 16.2 (10.5-17.7) h versus 6.9 (6.1-9.4) h (P = 0.03). These results confirm that enoximone pharmacokinetics in infants is similar to that found in adults. The infusion rate of enoximone should be reduced if hepatic or renal dysfunction supervenes.

Pharmacokinetics of tramadol in children after i.v. or caudal epidural administration.

We have studied the pharmacokinetics of a single bolus dose of tramadol 2 mg kg-1 injected either i.v. or into the caudal epidural space in 14 healthy children, aged 1-12 yr, undergoing elective limb, urogenital or thoracic surgery. Serum concentrations of tramadol and its metabolite O-demethyl tramadol (MI) were measured in venous blood samples at various intervals up to 20 h by non-stereoselective gas chromatography with nitrogen-selective detection. All pharmacokinetic variables were evaluated using a non-compartmental model. After a single i.v. injection (n = 9), the mean elimination half-life of tramadol was 6.4 (SD 2.7) h, with a volume of distribution of 3.1 (1.1) litre kg-1 and total plasma clearance of 6.1 (2.5) ml kg-1 min-1. All of these pharmacokinetic variables were similar to those reported previously in adults. After caudal epidural administration (n = 5), mean elimination half-life was 3.7 (0.9) h, volume of distribution was 2.0 (0.4) litre kg-1 and total clearance was 6.6 (1.9) ml kg-1 min-1. The caudal/i.v. quotient of the AUC was 0.83, which confirms that there is extensive systemic absorption of tramadol after caudal administration. Serum concentrations of MI showed a time course typical of a metabolite after both modes of administration. Serum concentrations of MI after caudal administration were lower than those after i.v. injection.

A placebo-controlled study of the effects of dopexamine on gastric mucosal perfusion in infants undergoing hypothermic cardiopulmonary bypass.

We used a laser Doppler probe to measure gastric mucosal blood flow (flux) and a paediatric tonometer to intermittently calculate gastric-arterial PCO2 difference (PrCO2-PaCO2 gap) in 50 infants aged 0.3-52 weeks who required hypothermic cardiopulmonary bypass (CPB). During CPB, patients in group 2 (n = 25) were given dopexamine 1.0 mg kg-1 over 5 min, followed by an infusion of 2 micrograms kg-1 min-1. Patients in group 1 (n = 25) received an equal volume of saline. Drug allocation was random and blinded. Measurements of flux, PrCO2-PaCO2 gap and mean femoral arterial pressure (MAP) were made over 5 min during steady state before and after cooling on CPB to 18-24 degrees C. MAP and blood lactate concentrations were similar in both groups throughout CPB. Mean flux decreased from 182 (SD 60) at the beginning of CPB to 158 (51) after rewarming on CPB in group 1, whereas it increased from 180 (56) to 196 (49) in group 2. This post-rewarm flux was significantly greater in group 2 than in group 1 (P = 0.01). Similarly, mean PrCO2-PaCO2 gap increased significantly from 3.6 (6.3) to 8.2 (6.7) in group 1 (P = 0.01) compared with a significant decrease from 5.8 (5.5) to 2.1 (5.5) in group 2 (P = 0.02). Mean PrCO2-PaCO2 gap after rewarming in group 2 was significantly higher than that in group 1 (P = 0.001). These data indicate that dopexamine may be useful in maintaining normal gut perfusion in infants requiring hypothermic CPB.

Angiotensin II concentrations and gut mucosal perfusion in infants undergoing cardiopulmonary bypass.

OBJECTIVES: To determine whether hypothermic cardiopulmonary bypass (CPB) per se causes an increase in angiotensin II (A-II) concentration in infants and to investigate the relationship between A-II concentration and gut mucosal perfusion. DESIGN: Prospective, open, nonrandomized, observational study. SETTING: Children's teaching hospital. PARTICIPANTS: Thirty acyanotic infants requiring CPB. INTERVENTIONS: A-II concentrations were measured on six occasions before, during, and after CPB. An orogastric tonometer allowed intermittent calculations of gastric intramucosal pH (pHi). Gastric mucosal blood flow (flux) was monitored using a laser Doppler flowmeter. Ten infants acted as controls (group 1); 10 infants received captopril, 0.9 mg/kg orally, 45 minutes before induction of anesthesia (group 2), and 10 infants received enalaprilat, 0.06 mg/kg intravenously, just before CPB (group 3). MEASUREMENTS AND MAIN RESULTS: A-II concentrations were abnormally high in 28 of 30 patients before CPB (median, 450 pg/mL (range, 83 to 5,787 pg/mL). A-II concentrations in groups 1 and 2 decreased during CPB, but values remained at twice normal levels throughout surgery (median, 171 to 198 pg/mL post-CPB). A-II concentrations remained normal (range, 52 to 120 pg/mL) during and after CPB in patients receiving enalaprilat (group 3). The authors found no significant correlation between A-II concentration and pHi or flux before, during, or after surgery. CONCLUSIONS: Acyanotic infants requiring cardiac surgery may have high perioperative concentrations of A-II. Hypothermic CPB is associated with a decrease in A-II concentration. Reductions in gut mucosal perfusion seen in some infants during hypothermic CPB are not related to increases in A-II concentrations.

Intraaortic balloon pumping in children.

BACKGROUND: Intraaortic balloon pump (IABP) usage in young children remains a rarity because, first, there is a widespread misconception that the greater elasticity of the aorta in children may prevent effective augmentation, and second, children in low cardiac output states are more likely to have associated right ventricular failure and pulmonary problems. We report our experience with the use of IABP in children undergoing cardiac surgery in whom mechanical support was necessary for the treatment of refractory cardiac failure. METHODS: Over a 3-year period, 14 children were identified as requiring IABP support after cardiac surgery. Their median age was 3 years (range 7 days to 13 years) and their median weight was 13.3 kg (range 3.5-51 kg). Indications for IABP use were: failure to wean from cardiopulmonary bypass (5 patients), sudden deterioration in intensive therapy unit (ITU) (3 patients), progressive deterioration in ITU (4 patients), and prophylactic therapy for known poor preoperative ventricular function (2 patients). RESULTS: Ten of 14 patients (71%) were successfully weaned from the IABP, of whom 8 became long-term survivors (57%). Among the survivors, the mean duration of IABP usage was 127 h (range 12-260 h), while for those who died while on IABP, the mean duration was 15 h (range 8-24 h). The most major IABP-related complication encountered was mesenteric ischemia, which had a fatal outcome. CONCLUSIONS: IABP therapy, used as an adjunct to conventional medical treatment, can give properly selected young children in refractory low cardiac output states after heart surgery a greater than 50% chance of long-term survival.

Thromboembolism leading to myocardial ischaemia in a patient requiring a fenestrated Fontan operation.

We report a case of air/thromboembolism of the left anterior descending coronary artery complicating a fenestrated Fontan procedure treated with aprotinin. The patient was successfully treated by saphenous vein grafting to the left anterior descending coronary artery and reconversion of the Fontan circulation to the original cavo-pulmonary connection.

Caudal tramadol for postoperative analgesia in pediatric hypospadias surgery.

Ninety boys, aged 13-53 months, undergoing repair of hypospadias, were allocated randomly to receive 0.8 ml kg-1 of one of three solutions into the caudal extradural space: group B received bupivacaine 2 mg kg-1, group T received tramadol 2 mg kg-1 in 0.9% saline and group BT a mixture of both. Postoperative pain was assessed hourly for 12 h after injection using a modified TPPPS pain score and additional analgesia was administered to those children whose pain scores were > 3/10. Nine patients (30%) in group T required additional analgesia within 1 h of surgery compared with only two (6.7%) and three (10%) patients in groups B and BT, respectively (P = 0.04). Mean duration before additional analgesia was required in the remaining patients was 9.3 (SD 3.0) h in group B, 10.7 (2.2) h in group T and 10.5 (2.0) h in group BT (P > 0.20). There were no significant differences between the groups in mean ventilatory frequency, sedation scores, incidence of emesis, facial flushing or pruritus. We conclude that caudal tramadol had a slow onset of action and that the addition of tramadol to bupivacaine, when both drugs were administered caudally, did not significantly prolong the duration of action of bupivacaine.