PubMed Health⌕ Search

Biomedical subjects

P D Booker

Publications and source records attributed to P D Booker.

At least 19 recordsLinked to original sources
PubMed2001

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.

Adolescent↗
PubMed2001

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.

Antiemetics↗
PubMed2001

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.

Anesthesia, General↗
PubMed2000

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.

Enoximone↗
PubMed2000

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.

Adrenergic beta-Agonists↗
PubMed2000

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.

Analgesia↗
PubMed1999

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.

Cardiopulmonary Bypass↗
PubMed1999

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.

Angiotensin II↗
PubMed1997

Bilateral continuous paravertebral block used for postoperative analgesia in an infant having bilateral thoracotomy.

We describe the successful postoperative pain management in an 11-month-old infant who underwent bilateral thoracotomy, using continuous infusions of bupivacaine into two directly placed paravertebral catheters. Haemodynamic parameters and pain scores were measured 1-2 h for 60 h while the infusions were continued and, intermittently, blood samples were taken for subsequent measurement of serum bupivacaine concentrations. The technique provided effective pain relief and the infant required no other analgesia postoperatively. There were no adverse haemodynamic consequences or complications relating to either catheter placement or drug infusions. Serum concentrations of bupivacaine remained below toxic levels throughout the study period, though accumulation did occur.

Analgesia↗
PubMed1997

Gut mucosal perfusion in infants undergoing cardiopulmonary bypass: effect of preoperative captopril.

We have studied gut mucosal perfusion in 24 infants, aged 0.7-45 weeks, requiring cardiopulmonary bypass (CPB). Group 2 patients (n = 12) had received the angiotensin converting enzyme inhibitor captopril 0.8-0.9 mg kg-1 orally, 45 min before induction of anaesthesia. Group 1 infants were of similar age and size and required a similar duration of CPB, but did not receive any preoperative medication. An orogastric tonometer allowed intermittent calculations of gastric intramucosal pH (pHi), and rectal mucosal perfusion ("flux") was monitored using laser Doppler flowmetry. Measurements of arterial base deficit and lactate and pyruvate concentrations were made intermittently. We found no significant difference in femoral arterial pressure between the groups at any time before, during or after surgery. Similarly, we found no significant differences in our measures of regional or global tissue perfusion between the groups at any time before, during or after surgery. We conclude that preoperative administration of captopril produced no beneficial effect on gut mucosal perfusion in infants undergoing hypothermic, non-pulsatile CPB.

Angiotensin-Converting Enzyme Inhibitors↗