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I Jenkins

Publications and source records attributed to I Jenkins.

16 recordsLinked to original sources
PubMed2000

Reducing stress responses in the pre-bypass phase of open heart surgery in infants and young children: a comparison of different fentanyl doses.

High-dose opioids are advocated for paediatric cardiac surgery to suppress stress responses but they can produce unwanted side effects. There are no data on the dose-dependent effects of opioids on the stress response on which to base rational opioid administration. We conducted a dose ranging study on 40 children less than 4 yr undergoing elective open heart surgery using one of five fentanyl doses: 2, 25, 50, 100 or 150 micrograms kg-1 before surgery. The standardized anaesthetic also included pancuronium and isoflurane. Blood samples were taken at induction, before incision, after sternotomy, immediately before, and at the end of cardiopulmonary bypass. Patients in the 2 micrograms kg-1 group had significant rises in prebypass glucose (P < 0.01), pre- and post-bypass cortisol (P < 0.01), and pre- and post-bypass norepinephrine (P < 0.01). No significant rise occurred in glucose, cortisol and catecholamines in any of the higher dosage groups. Patients in the 2 micrograms kg-1 group had significantly higher mean systolic blood pressure (P < 0.02) and heart rate (P < 0.04). A balanced anaesthetic containing fentanyl 25-50 micrograms kg-1 is sufficient to obtund haemodynamic and stress responses to the pre-bypass phase of surgery. Higher doses of fentanyl (100 and 150 micrograms kg-1) offer little advantage over 50 micrograms kg-1, and can necessitate intervention to prevent hypotension.

Anesthesia, General↗
PubMed2000

Intravenous clonidine infusion in critically ill children: dose-dependent sedative effects and cardiovascular stability.

Clonidine is used for analgesia and sedation in paediatric anaesthesia, but there are no data on its sedative properties and side effects in critically ill children. We studied 30 ventilated children aged 10 yr and under to determine an effective i.v. dosing range and to assess its cardiovascular effects. Twenty non-paralysed, ventilated children were given a background infusion of midazolam 50 micrograms kg-1 h-1 combined with a variable clonidine infusion (0.1-2 micrograms kg-1 h-1) to maintain optimal sedation. The effects of clonidine 1 microgram kg-1 h-1 on cardiac index were measured in 10 postoperative cardiac patients using a reverse Fick method. Dose-dependent sedation was achievable (713 out of 861 h) without cardiovascular side effects, but an infusion limit of clonidine 1 microgram kg-1 h-1 was inadequate in two patients. An increased dose limit of 2 micrograms kg-1 h-1 combined with midazolam 50 micrograms kg-1 h-1 achieved satisfactory sedation scores for 602 out of a total of 672 h studied with no failures. Clonidine in combination with midazolam at 1 microgram kg-1 h-1 was not associated with significant changes in heart rate arterial pressure or cardiac index.

Adrenergic alpha-Agonists↗
PubMed1998

The outcome of children requiring admission to an intensive care unit following bone marrow transplantation.

We report the results of a retrospective study of the role of intensive care unit (ICU) admission in the management of 367 children who underwent bone marrow transplantation (BMT) at a tertiary referral institution. 39 patients (11%) required 44 ICU admissions for a median of 6 d. 70% received marrow from unrelated donors, half of which were mismatched; 80% had leukaemia and two-thirds were considered high-risk transplants. Respiratory failure was the major reason for admission to ICU. 75% of admissions required mechanical ventilation (for a median of 5 d) and 20 patients had lung injury as defined by the criteria of the Seattle group. None of 11 patients with proven viral pneumonitis survived (P = 0.06) and only one of 20 patients with lung injury survived (P < 0.01). Six of seven patients with a primary neurological problem survived (P < 0.001); these appear to represent a good outcome group. Age, the presence of graft-versus-host disease, the use of inotropes, isolated renal or hepatic impairment, and paediatric risk of mortality (PRISM) score were not predictive of outcome. In total, 12 patients (27% of admissions) survived and were discharged from hospital 30d or more after admission and eight (18%) survived >6 months. ICU admission can be beneficial to selected children post-BMT but it may be less useful in proven viral pneumonitis. Where mechanical ventilation is required, the duration of this support should be limited unless there is rapid improvement.

Acute Disease↗
PubMed1998

DNA sequence sampling of the Streptococcus pneumoniae genome to identify novel targets for antibiotic development.

We initiated a survey of the Streptococcus pneumoniae genome by DNA sequence sampling. More than 9,500 random DNA sequences of approximately 500 bases average length were determined. Partial sequences sufficient to identify approximately 95% of the aminoacyl tRNA synthetase genes and ribosomal protein (rps) genes were found by comparing the database of partial sequences to known sequences from other organisms. Many genes involved in DNA replication, repair, and mutagenesis are present in S. pneumoniae. Genes for the major subunits of RNA polymerase are also present, as are genes for two alternative sigma factors, rpoD and rpoN. Many genes necessary for amino acid or cofactor biosynthesis and aerobic energy metabolism in other bacteria appear to be absent from the S. pneumoniae genome. A number of genes involved in cell wall biosynthesis and septation were identified, including six homologs to different penicillin binding proteins. Interestingly, four genes involved in the addition of D-alanine to lipoteicoic acid in other gram positive bacteria were found, even though the lipoteicoic acid in S. pneumoniae has not been shown to contain D-alanine. The S. pneumoniae genome contains a number of chaperonin genes similar to those found in other bacteria, but apparently does not contain genes involved in the type III secretion commonly observed in gram negative pathogens. The G+C content of S. pneumoniae genomic DNA is approximately 43 mole percent and the size of the genome is approximately 2.0 Mb as determined by pulsed-field gel electrophoresis. Many of the genes identified by sequence sampling have been physically mapped to the 19 different SmaI fragments derived from the S. pneumoniae genome. The database of random genome sequence tags (GSTs) provides the starting material for determining the complete genome sequence, gene disruption analysis, and comparative genomics to identify novel targets for antibiotic development.

Amino Acyl-tRNA Synthetases↗
PubMed1991

Postbypass hypothermia and its relationship to the energy balance of cardiopulmonary bypass.

Using a newly developed computerized intraoperative data acquisition system, the apparent adequacy of rewarming and its relation to the energy exchange between the patient and the bypass system was investigated. Retrospective analysis of comparable patients identified two groups that had, at the end of surgery, either a nasopharyngeal temperature (NPT) of 36 degrees C or more ("warm" group, n = 19), or a NPT of 35 degrees C or less ("cold" group, n = 19). Temperatures from the nasopharynx, thenar eminence skin, and bypass pump arterial and venous lines were continually recorded and sent to the computer data base together with the pump flow rate. There were no significant differences between the groups regarding time on perfusion, time taken to cool, time of hypothermia, or the time interval from end of perfusion to the end of surgery. However, rewarming time was greater in the warm group (P less than 0.01). The cold group were subjected to more profound hypothermia (P less than 0.001), and had lower NPTs and skin temperatures at the end of bypass (P less than 0.0001 and P less than 0.01, respectively). However, the difference between NPT and thenar skin temperature in each group at either the end of bypass or the end of surgery was the same. The net energy exchange between patient and pump was significantly different (mean in warm, 130 kJ [SD = 530]; in cold, -389 kJ [SD = 427]; P less than 0.003). In conclusion, the adequacy of rewarming can be expressed in terms of the energy exchanged in the bypass system, and cannot be assessed by the nasopharynx:skin temperature gradient.

Anesthesia, Intravenous↗
PubMed1988

Clinical effect of Bretschneider-HTK and St. Thomas cardioplegia on hemodynamic performance after bypass measured using an automatic datalogging database system.

A prospective consecutive study was undertaken to compare the hemodynamic effect of two cardioplegic solutions in CABG patients after bypass, and in relation to aorta occlusion time with the support of a automatic datalogging database. A total of 249 patients were randomized. One group received Bretschneider cardioplegic HTK solution (132 patients, group I) the other group received St. Thomas cardioplegic solution (117 patients, group II). The data was divided in four periods of aortic clamp time: less than or equal to 40 min (group I 26 patients, group II 32 patients); 41-60 min (group I 49 patients, group II 47 patients); 61-80 min (group I 30 patients, group II 29 patients); and greater than 80 minutes (group I 27 pts, group II 9 patients). Anesthesia regime and therapeutic drugs and infusions were given in both groups in similar dosages. Within both groups HR, CO, PAP, PCWP increased after bypass in relation to prebypass values. SVR decreased in both groups by 30%, MAP and PVR decreased only in group I. Between group I and II differences were found in the CI (3.0 vs. 3.3 l/min/m2), MAP (70 vs. 76 mmHg), PMAR (18 vs. 16 mHg), and SVR (827 vs. 954 dyn.sec.cm-5). In significantly more of the patients in group I, sinus rhythm started spontaneously after the release of the aorta clamp (39.5% vs. 20.4%, p less than 0.005). Patients in group I needed temporarily a pacemaker after bypass in 6.3% cases (in 1.1% of patients in group II,). There was no relation of the hemodynamic data in relation to aorta occlusion time within the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bicarbonates↗
PubMed1987

Carola, a computer system for automatic documentation in anesthesia.

A computer system has been designed for documentation and data acquisition during open heart surgery. This computer system (called 'Carola') processes all patient data during cardiac surgery. More than 50 analogue or digital signals are scanned. These are derived from a monitoring rack, a Siemens Servo 900B ventilator with its accessory devices and a heart lung machine. All these values are plotted as well as offline data, such as medications, fluids, laboratory results and user comments, on an A3 format anesthetic record using an eight pen flat bed plotter. Simultaneously all data is written onto a cassette tape. These tapes are then transferred to a database for storage and statistical processing. The sampling frequency is every 10 seconds, averages being calculated over one minute periods. The chart is updated once a minute normally or every 15 minutes for slowly changing signals e.g. temperatures. Hardware and software of the computer have modular design. The hardware consists of two Motorola 6809 based microprocessor systems. The software is entirely written in Pascal. The user interface is implemented on a menu driven basis. A terminal with a keyboard is used for the communication with the users, namely anesthetic nurses and anesthesiologists. The system was readily accepted by the users. The menu structure proved to be easy to learn and allowed fast entries, even when the users were not previously accustomed to the use of a keyboard. The clear and detailed presentation of the data on the plotted chart helped to detect trends early and facilitated therapeutic decisions. From december 1983 the first prototype was used on a routine basis, followed by a second unit in June 1984 and a third in December 1985. Up to now more than 12.500 anesthetic hours have been recorded. Since then almost 100% of all anesthetics performed in our cardiothoracic unit have been documented by the computers, including all short procedures without invasive monitoring and all emergencies.

Anesthesiology↗
PubMed1977

Adult respiratory distress syndrome.

The authors correlated and presented clinical, radiological and pathological findings in 6 patients with Adult Respiratory Distress Syndrome (ARDS): It is a distinct syndrome with characteristic clinical, radiological presentations and pathological findings. It is a unique response of lung to a variety of primary insults. If unrecognized, patients with this syndrome are often fatal. Its possible pathognesis is discussed.

Adult↗