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Biomedical subjects

A J Petros

Publications and source records attributed to A J Petros.

At least 19 recordsLinked to original sources
PubMed2006

How many oxygen cylinders do you need to take on transport? A nomogram for cylinder size and duration.

When undertaking patient retrieval, it is important to take adequate supplies of oxygen to ensure patient safety. Oxygen can be delivered via a flowmeter into a facemask or used to drive pneumatic ventilators. Given the lack of space in the back of an ambulance or helicopter, the numbers of cylinders that can be taken is limited, hence the number needed to complete the journey must be carefully calculated prior to embarking. We have produced nomograms to predict how many oxygen cylinders will be consumed during a given journey when using either a flowmeter or a commonly used transport ventilator.

Equipment Design↗
PubMed2005

Handwashing in the intensive care unit: a big measure with modest effects.

Handwashing is widely accepted as the cornerstone of infection control in the intensive care unit. Nosocomial infections are frequently viewed as an indicator of poor compliance of handwashing. The aim of this review is to evaluate the effectiveness of handwashing on infection rates in the intensive care unit, and to analyse the failure of handwashing. A literature search identified nine studies that evaluated the impact of handwashing or hand hygiene on infection rates, and demonstrated a low level of evidence for the efforts to control infection with handwashing. Poor compliance cannot be blamed as the only reason for the failure of handwashing to control infection. Handwashing on its own does not abolish, but only reduces transmission, as it is dependent on the bacterial load on the hand of healthcare workers. Finally, recent studies, using surveillance cultures of throat and rectum, have shown that, under ideal circumstances, handwashing can only influence 40% of all intensive care unit infections. A randomised clinical trial with the intensive care as randomisation unit is required to support handwashing as the cornerstone of infection control.

Clinical Trials as Topic↗
PubMed2005

Challenges in the provision of ICU services to HIV infected children in resource poor settings: a South African case study.

The HIV/AIDS epidemic has placed increasing demands on limited paediatric intensive care services in developing countries. The decision to admit HIV infected children with Pneumocystis carinii pneumonia (PCP) into the paediatric intensive care unit (PICU) has to be made on the best available evidence of outcome and the ethical principles guiding appropriate use of scarce resources. The difficulty in confirming the diagnosis of HIV infection and PCP in infancy, issues around HIV counselling, and the variance in the outcome of HIV infected children with PCP admitted to the PICU in African studies compound this process. Pragmatic decision making will require evaluation of at least three ethical questions: are there clinical and moral reasons for admitting HIV positive children with PCP to the PICU, should more resources be committed to caring for HIV children who require the PICU, and how can we morally choose candidates for the PICU? Those working in the PICU in HIV endemic regions need to make difficult personal decisions on effective triage of admissions of HIV infected children with PCP based on individual case presentation, availability of resources, and applicable ethical principles.

Child↗
PubMed2003

Non-invasive diagnosis of tracheobronchomalacia using a modified ventilation radioisotope lung scan.

The use of radionuclide ventilation lung scan to characterise the physiological effects of tracheobronchomalacia is a novel application of this non-invasive technique. In the reported case the right upper lobe was found to be not ventilated below a pressure of 20 cm H2O despite evidence from a dynamic tracheobronchogram of the right upper lobe bronchus opening at the lower pressure of 15 cm H2O.

Bronchial Diseases↗
PubMed2001

Cerebro-splanchnic oxygenation ratio (CSOR) using near infrared spectroscopy may be able to predict splanchnic ischaemia in neonates.

OBJECTIVE: To investigate whether near infrared spectroscopy (NIRS) can detect differences in oxyhaemoglobin signal when applied to the abdomens of neonates with surgically proven splanchnic ischaemia. DESIGN: Prospective, observational cohort study. SETTING: Tertiary neonatal referral centre. PATIENTS: Medical and surgical neonates were studied. Two groups were identified, neonates with acute abdomens referred for surgery and those with normal abdomens admitted for medical reasons. INTERVENTIONS: Tissue oxygenation indexes (TOI) of cerebral and splanchnic regions were measured using near infrared spectroscopy (NIRS) and their relative values expressed as a cerebro-splanchnic oxygenation ratio (CSOR). Measurements were made on admission or immediately prior to surgery and subsequently repeated on a daily basis, whenever possible, until discharge from our unit. The area under the receiver operating characteristic (ROC) curve was evaluated and optimum diagnostic cut-off values determined. RESULTS: Forty neonates were studied: 10 with acute abdomens, including four with necrotising enterocolitis (NEC), 29 controls with normal abdomens and one with cerebral hypoxic ischaemic injury. Median CSOR for the control group was 0.96 (interquartile range 0.83-1.02) whereas the acute abdomen group had a significantly lower median CSOR value of 0.66 (0.45-0.69) (p<0.001). The area under the ROC was 0.91 (95% confidence limits 0.78-1.00) for CSOR. Taking a boundary value of CSOR for the prediction of splanchnic ischaemia as less than 0.75, intestinal ischaemia was identified with a positive predictive value of 0.75 (0.43-0.95) and excluded with a negative predictive value of 0.96 (0.81-1.0). This was a better performance than using abdominal TOI alone. CONCLUSIONS: By comparing the TOI of cerebral and splanchnic regions it may be possible to establish the presence of normal splanchnic perfusion and detect when splanchnic ischaemia develops. CSOR had a 90% (56-100%) sensitivity to detect splanchnic ischaemia in neonates. Further work is necessary to confirm these early findings and establish whether abdominal NIRS has a clinical role in detecting splanchnic ischaemia.

Abdomen, Acute↗
PubMed2001

Prolonged use of tissue plasminogen activator for bilateral lower limb arterial occlusion in a neonate.

The authors report the case of a 29-week-gestation twin with very severe vascular compromise of both lower limbs secondary to premature twin-twin transfusion. A tissue plasminogen activator (tPA) infusion was used locally for 13 days with complete recovery of perfusion to both legs, demonstrated by serial angiograms, thereby avoiding bilateral amputation. There were no side effects as a result of the continuous administration of tPA. The authors therefore suggest that the benefits of thrombolysis from a local infusion of tPA in neonates may outweigh the potential risks. This case report thus supports the view that under certain circumstances infusion of tPA in neonates may offer significant benefits. J Pediatr Surg 36:654-656.

Angiography↗
PubMed2001

Energy metabolism of infants and children with systemic inflammatory response syndrome and sepsis.

OBJECTIVE: To evaluate whether critically ill children with systemic inflammatory response syndrome (SIRS) or sepsis have altered resting energy expenditure (REE) and substrate utilization. SUMMARY BACKGROUND DATA: Studies in adults with sepsis have shown increased energy expenditure and mobilization of endogenous fat. In infants and children, energy metabolism and substrate utilization during sepsis have not been characterized. METHODS: Metabolic studies were performed in 21 critically ill children with SIRS or sepsis. Twenty-one stable control children, matched for weight, were also studied. Seven patients required inotropic support and 17 received mechanical ventilation. Fifteen patients with SIRS had evidence of bacterial, fungal, or viral infection and were considered septic. Respiratory gas exchange was measured by computerized indirect calorimetry for 1 to 2 hours continuously. RESULTS: The REE of patients with SIRS or sepsis was not different from that of controls. Similarly, there were no differences in carbon dioxide production and oxygen consumption. Resting energy metabolism was not different between patients with SIRS and patients with sepsis. In addition, the presence of low platelet count or inotropic support did not affect resting energy metabolism. The median respiratory quotient of patients with SIRS or sepsis was 0.88 (range 0.75-1.12), indicating mixed utilization of fat and carbohydrate; this was not significantly different from that of controls. The Pediatric Risk of Mortality Score was not significantly correlated with REE or respiratory quotient. CONCLUSIONS: The energy requirements of children with SIRS or sepsis are not increased. Their resting metabolism is based on both carbohydrate and fat utilization. The authors speculate that these children divert the energy for growth into recovery processes.

Case-Control Studies↗
PubMed2001

Systemic antibiotics fail to clear multidrug-resistant Klebsiella from a pediatric ICU.

STUDY OBJECTIVES: To determine the magnitude of infection rate and antimicrobial resistance in a pediatric ICU (PICU), and to evaluate the efficacy of using broad-spectrum antibiotics. DESIGN: A 3-month, prospective, observational cohort audit. SETTING: A 12-bed tertiary, referral PICU. PATIENTS OR PARTICIPANTS: All children admitted to the PICU for > 72 h. INTERVENTIONS: Surveillance cultures of throat and rectum on admission and once weekly thereafter. MEASUREMENTS AND RESULTS: Of the 150 admissions during the 3-month period, a total of 52 patients (24 girls and 28 boys) requiring mechanical ventilation for a minimum of 3 days were enrolled in the audit. The median age and interquartile range (IQR) was 17 months (IQR, 5.8 to 63); length of stay, 6.5 days (IQR, 4 to 13); ventilation days, 5 (IQR, 3 to 11); pediatric risk of mortality score, 14 (IQR, 9 to 19); and risk of mortality, 0.03 (IQR, 0.014 to 0.087). Fifteen patients (29%) developed 21 infections, mainly lower-airway infections and septicemias. Of the 52 children, 7 children carried multidrug-resistant bacteria and 3 patients progressed to develop four infections with those resistant bacteria. Of the seven carriers, six patients carried gentamicin-resistant Klebsiella. Methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae and gentamicin-resistant Pseudomonas aeruginosa each were carried by one child. Six of those nine resistant isolates were present in the admission flora. Despite the potent combination of piperacillin/tazobactam and amikacin, three children acquired the multidrug-resistant Klebsiella while in the PICU and became nosocomial carriers. CONCLUSIONS: Only surveillance cultures allow the distinction between import of multidrug-resistance and resistant bacteria acquired while in PICU. In this study, two thirds of the resistant isolates were imported. The introduction of newer potent systemic antibiotic combinations failed to control the endemic reservoir of multidrug-resistant Klebsiella and suggests that such policies have little impact.

Amikacin↗
PubMed1999

Use of the laryngeal mask airway during repair of atrial septal defect in children.

We describe the elective use of the laryngeal mask airway in two children undergoing cardiopulmonary bypass for repair of an atrial septal defect. Total surgical time was short and cardiopulmonary bypass performed at normothermia allowing removal of the laryngeal mask airway on the operating table on completion of surgery. We were able to adequately oxygenate and ventilate the children throughout the procedure using positive pressure ventilation and spontaneous ventilation. The use of caudal fentanyl and rectal diclofenac aided postoperative pain management. Atrial septal defect repair has become one of the more straightforward cardiac operations partly as a result of new cardiopulmonary bypass techniques. Avoidance of intubation and postoperative ventilation in appropriate patients would make this procedure ideal for 'fast tracking' and offers the potential advantages of decreased length of stay in hospital and reduction in overall costs.

Administration, Rectal↗
PubMed1999

Position of the internal jugular vein in children. A study of the anatomy using ultrasonography.

The relative anatomy of the internal jugular vein (IJV) was studied in 25 patients undergoing cardiac catheterization under general anaesthesia, with the use of a portable ultrasound probe. In 14 of cases the IJV was anterior, 1 anterolateral and in 10 lateral to the carotid artery between the two heads of the sternocleidomastoid muscle. At the level of the cricoid cartilage, in six cases the IJV was anterior, three anterolateral and in 16 of children the IJV was lateral to the carotid artery. When attempting to cannulate the IJV, because of the variability in relationship of the IJV to CA the technique used should be modified depending upon the level at which cannulation is attempted. The position of the IJV in the child appears to be so variable extra care should be taken when cannulating the IJV and it should not be assumed that the techniques used in adults are directly transferable.

Adolescent↗