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Biomedical subjects

R Fitzgerald

Publications and source records attributed to R Fitzgerald.

At least 37 records · Page 2Linked to original sources
PubMed1997

Changes in oxygenation variables during progressive hypothermia in anesthetized patients.

Because deliberate hypothermia is becoming commonly used during neurosurgery, this study was performed to investigate the effects of a progressive reduction of body core temperature (T) on whole body oxygenation variables in patients undergoing elective intracranial surgery. In 13 patients (Hypothermic Group), T was reduced to 32.0 degrees C using convective-based surface cooling. In six patients (Control Group), T was maintained at 35.5 degrees C during the entire study period. The cardiac index (CI) was determined with a pulmonary artery catheter by thermodilution. Whole body oxygen delivery (DO2) was calculated from CI and arterial oxygen content. Whole body oxygen consumption (VO2), carbon dioxide production (VCO2), and energy expenditure (EE) were determined by ventilation gas analysis (indirect calorimetry). Mixed venous oxygen tension at 50% saturated hemoglobin (P50), and whole body oxygen extraction ratio (O2ER) were calculated. Repeated-measures analysis of variance and the Mann-Whitney test were used for statistical analysis. Data are expressed as means +/- SD. VO2 (from 100 +/- 13 to 77 +/- 11 ml.min-1.m-2), VCO2 (from 75 +/- 7 to 57 +/- 7 ml.min-1. m-2), EE (from 667 +/- 67 to 509 +/- 66 kcal.d-1.m-2), P50 (from 23.8 +/- 1.7 to 20 +/- 0.9 mm Hg), and O2ER (from 0.29 +/- 0.05 to 0.22 +/- 0.03%) decreased significantly in the Hypothermic Group between 35.5 and 32.0 degrees C (p < 0.05). None of these variables changed in the Control Group and at 32.0 degrees C VO2, VCO2, EE, P50, and O2ER were significantly lower in the Hypothermic Group than in the Control Group. DO2 remained unchanged in both groups. We conclude that progressive hypothermia in anesthetized patients reduces metabolic rate but does not change DO2. The significant decrease in O2ER may partly be related to a leftward shift of the oxyhemoglobin dissociation curve, as evidenced by the decrease in P50.

Aged↗
PubMed1995

Optimal values for oxygen transport during hypothermia in sepsis and ARDS.

Mild hypothermia (33 degrees C to 35.5 degrees C) is reported to improve oxygenation and survival in patients with lung failure (1). Although hypermetabolism may account for about 50% of the ventilatory demand in ARDS patients, the concept of reducing oxygen consumption (VO2) by lowering metabolic rate, has only recently gained attention (2). Our study was aimed to test whether mild hypothermia established by continuous veno-venous haemofiltration (CVVHF), could optimize values for oxygen kinetics in ARDS patients. Overall, we recruited 27 patients with ARDS and sepsis. Prior initiation of CVVHF patients had to meet the following criteria: a) Murray score > 2.5, and hypoxaemia with PaO2/FIO2 < 200, b) hyperthermia of > 38 degrees C, c) cardiovascular instability requiring inotropic support. Evaluation of cardio-respiratory data was performed within four different phases (I = before, II + III during and IV = after CVVHF) every 6 hours. Core temperature as derived from the thermistor of pulmonary artery catheter was aimed to be between 35.0 degrees C and 36.5 degrees C. Optimal values for oxygen delivery (DO2) (> 550 mL/min/m2) and VO2 (> 160 mL/min/m2) were defined according to Shoemaker and achieved by fluid loading, transfusion and inotropic support (3). Septic shock occurred in 10 of 14 nonsurvivors (nons) and 2 of 13 survivors (surv). Mean values for DO2 and VO2 were calculated at different body temperature ranges. While at 37 degrees C DO2 was identical between surv and nons, (663 +/- 128 versus 666 +/- 127 means +/- SD) moderate hypothermia led to a small decrease of DO2 in surv and a significant decrease in nons (632 +/- 134 versus 605 +/- 128 mL/min/m2) at 35 degrees C. Concerning VO2 during hypothermia, there was a significant drop in nonsurvivors while in survivors the decrease was less pronounced. We could demonstrate a decrease in DO2 and VO2 during mild hypothermia during CVVHF. However, decreases in nonsurvivors were more pronounced than in survivors. These results suggest that the inability to achieve optimal values for DO2 and VO2 during mild hypothermia induced by CVVHF could serve as a prognostic sign for fatal outcome. Although oxygen consumption is decreased during hypothermia, hypoxaemia may result due to alterations of the oxygen transport on a cellular basis. The relationship between oxygen transport and temperature during CVVHF therefore deserves further studies.

Adolescent↗
PubMed1995

Computed tomography manifestations of tricuspid regurgitation.

Six patients undergoing dynamic contrast enhanced abdominal computed tomography (CT) for upper abdominal symptoms and signs are described. Each patient demonstrated early, intense opacification of the inferior vena cava (IVC) and hepatic veins, exceeding that in the aorta on scans through the upper abdomen. Opacification of the IVC returned to normal on more caudal slices. All six patients were found to have echocardiographically proven tricuspid regurgitation (TR). It is suggested that this sign occurs in patients with TR due to direct reflux of contrast from the right atrium into the IVC during protracted bolus injection. Additional CT findings included patchy parenchymal liver enhancement in four patients and ascites in five. Recognition of this simple sign may direct the clinician to a cardiac aetiology for upper abdominal symptoms and signs.

Female↗
PubMed1994

Ultrasound-guided supraclavicular approach for regional anesthesia of the brachial plexus.

We prospectively studied 40 patients (ASA grades I-III) undergoing surgery of the forearm and hand, to investigate the use of ultrasonic cannula guidance for supraclavicular brachial plexus block and its effect on success rate and frequency of complications. Patients were randomized into Group S (supraclavicular paravascular approach; n = 20) and Group A (axillary approach; n = 20). Ultrasonographic study of the plexus sheath was done. After visualization of the anatomy, the plexus sheath was penetrated using a 24-gauge cannula. Plexus block was performed using 30 mL bupivacaine 0.5%. Onset of sensory and motor block of the radial, ulnar, and median nerves was recorded in 10-min intervals for 1 h. Satisfactory surgical anesthesia was attained in 95% of both groups. In Group A, 25% showed an incomplete sensory block of the musculocutaneous nerve, whereas all patients in Group S had a block of this nerve. Complete sensory block of the radial, median, and ulnar nerves was attained after an average of 40 min without a significant difference between the two groups. Because of the direct ultrasonic view of the cervical pleura, we had no cases of pneumothorax. An accidental puncture of subclavian or axillary vessels, as well as neurologic damage, was avoided in all cases. An ultrasonography-guided approach for supraclavicular block combines the safety of axillary block with the larger extent of block of the supraclavicular approach.

Adolescent↗
PubMed1994

Mediastinal computed tomography in a British Asian population.

We describe a retrospective review of all the thoracic computed tomography (CT) scans performed on British Asian patients at New Cross Hospital, Wolverhampton between January 1989 and April 1992. 39 patients were studied. Of 15 patients with active tuberculosis (TB), 14 showed mediastinal lymphadenopathy. In nine of these 15 patients this adenopathy was the only positive imaging finding, as neither lung parenchymal nor pleural abnormalities were detected on CT or plain chest radiograph (CXR). The patterns of node distribution and enhancement following intravenous contrast are described. We conclude that thoracic CT is useful in Asian or other high risk patients in whom active TB is suspected, but who lack definitive microbiological or CXR proof of diagnosis.

Adolescent↗
PubMed1994

A new device for blind oral intubation in routine and difficult airway management.

41 patients (ASA I-II) were intubated using a new device for blind oral intubation (Augustine Guide). A group of 33 consecutive patients (Mallampati I and II), was studied for routine intubation. Another group of eight patients (Mallampati III and IV) was selected to study the guide in difficult airway management. Intubation was successful in 31 of the 33 normal patients (two patients required a second attempt), and in seven of the eight patients in the difficult intubation group (three patients with two attempts). In the remaining three patients intubation had to be performed by direct laryngoscopy. One patient (Mallampati IV), was intubated by the Augustine guide after three unsuccessful attempts by direct laryngoscopy. The Augustine Guide proved to be helpful to intubating patients with an anterior larynx and receding mandible. However, blind oral intubation attempts required a median duration of 65 s (range 35-90 s). Patients with a low Mallampati score did not benefit from the new device.

Adolescent↗
PubMed1993

Case report: accessory lobe of the liver mimicking lesser omental lymphadenopathy.

An accessory lobe of the liver is an uncommon occurrence and often an incidental finding. We present the case of a middle-aged man whose upper abdominal pain was relieved following removal of an accessory lobe. His preoperative imaging had led us to believe that he had lesser omental lymphadenopathy. We draw attention to the fact that this congenital abnormality can cause diagnostic confusion.

Diagnosis, Differential↗
PubMed1990

A prospective randomised controlled trial of antimicrobial prophylaxis in hydrocephalus shunt surgery.

Despite attempts to reduce their incidence, shunt infections remain a major complication of the treatment of hydrocephalus. Various forms of antimicrobial prophylaxis are in use, but no controlled, statistically valid trial has been conducted to assess their efficacy. Such a trial was therefore carried out and its design is described here. After a 1-year retrospective and prospective study by members of the United Kingdom Hydrocephalus Group to establish feasibility and infection rates, a statistical study showed that at least 712 patients would be required. Six centres were enrolled to fulfil these requirements, and ethical committee approval was obtained at each. The chosen prophylactic regimen was 10 mg vancomycin administered into the ventricular system during surgery. Adults and children undergoing insertion or revision of ventriculoperitoneal shunts were included unless they were receiving therapeutic antimicrobials. Randomisation was by computer-generated numbers. Controls received the antimicrobial regimen, if any, currently used in that centre, the only difference between the two groups being intraventricular vancomycin in the test group. Diagnosis of shunt infection included accepted clinical and microbiological criteria reinforced by measurement of serum C-reactive protein levels. Follow-up was for at least six months. After 2.5 years only 158 patients had been enrolled in the trial, 80 controls and 78 tests. There were 5 preventable infections in the control group and 2 in the test group. In view of the small total the planned statistical analysis was not possible. Therefore, while no problems were encountered with toxicity, the trial failed to enroll enough patients to answer the question of efficacy of antimicrobial prophylaxis in shunt surgery and the reasons for this are discussed.

Cerebrospinal Fluid Shunts↗
PubMed1989

Out-patient lumbar radiculography with iohexol.

A prospective study of 200 patients undergoing lumbar radiculography using 10 ml iohexol (240 mgI/ml) was undertaken to determine whether the procedure could be safely performed on an out-patient basis. No statistically significant differences in the incidence and severity of side-effects were found between the 99 out-patients and 101 in-patient controls. Three out-patients had to be kept in hospital at the end of the observation period and a further three out-patients were re-admitted to hospital because of severe side-effects. Out-patient lumbar radiculography is a safe procedure provided there is careful patient selection, adequate advice and easy access to medical help should problems arise following the examination. Adopting this practice considerably reduces the cost of lumbar radiculography and indirectly increases the availability of orthopaedic beds.

Ambulatory Care↗
PubMed1989

Use of the appendix stump in the treatment of meconium ileus.

Three neonates with meconium ileus who failed to respond to non-operative measures were successfully treated by appendicectomy and irrigation with Gastrografin into the small bowel via the appendix stump. The meconium was emptied out and the stump ligated. This method avoids enterotomy, enterostomies or resection of bowel. The post-operative course is simplified and hospital stay decreased. Removal of the appendix precludes future disease of this organ which may be problematic in patients with cystic fibrosis.

Appendectomy↗
PubMed1989

Evaluation of chlordecone in a two-stage model of hepatocarcinogenesis: a significant sex difference in the hepatocellular carcinoma incidence.

Chlordecone (Kepone) has been extensively studied for its toxicity in male production workers who were exposed to large quantities of this organochlorine pesticide. Concern that these workers might be at an increased risk of developing liver cancer prompted us to test chlordecone in a two-stage rat model of hepatocarcinogenesis. Chlordecone acted largely as a liver tumor promoter rather than as a complete hepatic carcinogen in both male and female Sprague-Dawley rats. Dose-response experiments showed that the hepatocarcinogenic effects of long-term chlordecone administration became undetectable at concentrations in non-initiated rat liver in the same range as those measured in human biopsies taken from exposed workers who exhibited no liver effects. Although the toxicity of chlordecone in women has never been studied, we found a dramatic sex difference in the incidence of malignant liver tumors caused by chlordecone promotion in rats. Frank hepatocellular carcinomas were observed in up to 63% of female rats whose livers were previously 'initiated' with a subcarcinogenic dose of diethylnitrosamine given 24 h after partial hepatectomy, and then 'promoted' by 27 weeks of chlordecone administration. In contrast, none of comparably treated males had malignant liver tumors, even after 44 weeks of 'promotion' with chlordecone. Females in the diethylnitrosamine-initiated/chlordecone-promotion groups also contained gamma-glutamyltranspeptidase-positive 'preneoplastic' hepatocellular foci that were more abundant and larger than those observed in comparably-treated males. Moreover, because similar levels of chlordecone were measured in the livers of both sexes at the end of the experimental period, the development of hepatocellular carcinomas in the diethylnitrosamine-initiated female rats appeared to be due to their increased sensitivity to the promotion treatment.

Animals↗