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Biomedical subjects

Robert H Friesen

Publications and source records attributed to Robert H Friesen.

10 recordsLinked to original sources
PubMed2006

A trial of fresh autologous whole blood to treat dilutional coagulopathy following cardiopulmonary bypass in infants.

BACKGROUND: Transfusion of fresh whole blood is superior to blood component therapy in correcting coagulopathies in children following cardiopulmonary bypass (CPB); however, a supply of fresh homologous whole blood is difficult to maintain. We hypothesized that transfusion of fresh autologous whole blood obtained prior to heparinization for CPB and infused following CPB would be associated with improved coagulation function when compared with standard therapy. METHODS: A total of 32 infants 5-12 kg undergoing noncomplex open cardiac surgery were randomly assigned to either the treatment or control group. In the treatment group, 15 ml x kg(-1) of autologous whole blood was collected into a CPDA bag prior to heparinization while 15 ml x kg(-1) of 5% albumin was infused intravenously. After reversal of heparin, coagulation tests were drawn in both groups, and the autologous whole blood was infused over 20 min in the treatment group. RESULTS: The treatment group had greater (P < 0.05) improvement in platelet count, prothrombin time, and fibrinogen than the control group. CONCLUSIONS: We conclude that collection of fresh autologous whole blood prior to heparinization and reinfusion following CPB is associated with greater improvement of coagulation status after CPB in infants.

Anticoagulants↗
PubMed2005

Pediatric sedation outside the operating room: the year in review.

PURPOSE OF REVIEW: This review is a survey of the recent literature concerning issues and trends in the rapidly changing field of pediatric sedation. RECENT FINDINGS: Clinical guidelines for the safe provision of sedation to children continue to be developed and revised. Systems for providing sedation are evolving, and the most successful models emerging are those that involve a dedicated team, either mobile or stationary, of physicians and nurses. A variety of drugs is used, and potent drugs that were designed as anesthetics, such as propofol and ketamine, are being administered outside the operating room by anesthesiologists and non-anesthesiologists. The safety of this practice continues to be debated. The reported incidence of adverse events is different in various settings and systems; however, outcome data are difficult to compare because of differences in study design and outcome definition. There is agreement that sedation is a continuum, and evidence that the depth of sedation attained during procedural sedation in children is often consistent with general anesthesia. Capnography and processed electroencephalogram monitoring have been described in sedation studies, may enhance safety during pediatric sedation, and should be investigated further. SUMMARY: The evolution of systems, drugs, and monitors for the provision of pediatric sedation is continuing. An accurate assessment of safety and other outcomes will be enhanced through the establishment of multicenter collaborative databases.

Journal Article↗
PubMed2005

Correlation of the Bispectral Index Monitor with the COMFORT scale in the pediatric intensive care unit.

OBJECTIVE: The COMFORT scale is a commonly used observational scoring system to assess the level of sedation in ventilated children in pediatric intensive care units (PICUs). The bispectral index (BIS) monitor is a processed electroencephalographic parameter that noninvasively measures the hypnotic effect of anesthetic and sedative drugs on the brain. The objective of this study was to assess the degree of correlation between the COMFORT scale and the BIS monitor. DESIGN: A prospective study in a tertiary level PICU. RESULTS: A total of 75 children were enrolled in the study, resulting in 869 valid paired observations of BIS values and COMFORT scores. The median age was 10 months, with a range of 1 month to 12 yrs. The median COMFORT score was 11 (range, 8-40). The median BIS value was 52 (range, 0-98). In a repeated-measures analysis, the correlation coefficient between COMFORT scores and BIS values averaged over time was 0.61 (p < .0001). CONCLUSIONS: The BIS monitor may be a valid and useful monitor of the level of sedation of children in the PICU. We cannot expect perfect correlation between BIS values and observational scales because they measure different variables. The BIS monitor may be the best objective monitor currently available for children receiving neuromuscular blockade because it does not rely on subjective measures such as those used in the COMFORT scale. The ability of the BIS monitor to distinguish between very deep levels of sedation may be useful to prevent over-sedation of children in PICUs and to help clarify the appropriate target level of sedation for each child.

Child↗
PubMed2004

Depth of consciousness and deep sedation attained in children as administered by nonanaesthesiologists in a children's hospital.

BACKGROUND: Sedation of children is administered by nonanaesthesiologists in a variety of locations within our children's hospital. The purpose of this study was to assess the depth of sedation administered to children in four locations using the Bispectral Index (BIS) and the University of Michigan Sedation Scale (UMSS). METHODS: Eighty-six children under the age of 12 years undergoing procedures with conscious or deep sedation were enrolled. The study included patients undergoing cardiac catheterization, computerized tomography imaging, gastrointestinal endoscopy, and dental procedures. Sedation for each procedure was based on departmental protocols and preferences; the study did not dictate choice or dose of drugs. An independent observer applied the UMSS sedation scale at 10 min intervals for 1 h. The observer and the personnel administering sedation were blinded to the BIS score, which was recorded continuously. RESULTS: The goal of either conscious or deep sedation was attained in 53% (BIS) and 72% (UMSS) of patients. Depth consistent with general anaesthesia was observed in 35% (BIS) and 0% (UMSS), and an awake state was observed in 12% (BIS) and 28% (UMSS). About 8% of patients experienced desaturation and airway events associated with deeper levels of sedation. CONCLUSIONS: Our data demonstrate wide variations in depth of sedation attained in the hospital. The goal of either conscious or deep sedation was not achieved in a significant number of children. This is a therapeutic failure that requires reassessment of sedation protocols and investigation of new approaches.

Anesthesia, General↗
PubMed2004

Sedation, analgesia, and neuromuscular blockade in the pediatric intensive care unit: survey of fellowship training programs.

OBJECTIVE: To survey current sedation, analgesia, and neuromuscular blockade practices in pediatric critical care fellowship training programs in the United States. DESIGN: Questionnaire survey sent by all program directors. The survey could be submitted either via a Web site, fax, or mail. SETTING: University school of medicine. SUBJECTS: Fifty-nine pediatric critical care fellowship training program directors in the United States, listed on the Accreditation Council for Graduate Medical Education Web site. INTERVENTIONS: Survey. MEASUREMENTS AND MAIN RESULTS: The response rate was 59.3% (35 questionnaires). Midazolam, lorazepam, morphine, and fentanyl are the most frequently used drugs in pediatric intensive care units for analgesia and sedation. Most pediatric intensive care units surveyed have a written sedation policy (66%). The majority of units responding to the survey (85.7%) routinely use a scoring system to assess agitation and pain in children, with the most common being the COMFORT score. All of the pediatric intensive care units surveyed reported weaning drugs slowly to try to prevent drug withdrawal. Movement disorders related to prolonged sedation and analgesia seem to be more common than is reported in the literature, with 65.7% of units reporting cases. There is good consensus on the indications for neuromuscular blockade, with vecuronium being the most popular drug. CONCLUSIONS: When compared with a similar survey from 1989, this survey suggests that pediatric critical care units with fellowship training programs have made some changes in their approach to sedation and analgesia over the past decade. More fellowship directors report the use of sedation protocols and better recognition, prevention, and management of drug withdrawal. Similar analgesic, sedative, and neuromuscular blocking drugs are being used but some more commonly than a decade ago.

Analgesics↗
PubMed2003

A comparison of remifentanil and fentanyl for fast track paediatric cardiac anaesthesia.

BACKGROUND: Fast track anaesthetic protocols for cardiac surgical patients have been developed to facilitate early tracheal extubation. We compared anaesthetics based on either remifentanil or fentanyl for fast track paediatric cardiac anaesthesia. METHODS: Fifty patients with atrial septal defect or simple ventricular septal defect who were deemed suitable for fast track anaesthetic management were randomly assigned to group R (remifentanil) or group F (fentanyl). After sevoflurane induction, patients received either R infusion or F bolus. Following intubation, isoflurane 0.5 MAC was administered to all patients. Blood pressure (BP) and heart rate (HR) were recorded at baseline and pre- and postinduction, intubation, skin incision and sternotomy. Other parameters measured included time to extubation, reintubation rate and requirements for postoperative analgesia, ondansetron, and nitroprusside in the paediatric intensive care unit. RESULTS: BP decreased similarly from baseline in both groups. Decreases in HR over time were significantly greater in group R. Haemodynamic response to incision/sternotomy was low and similar in both groups. There were no significant differences in extubation time, reintubation incidence, postoperative narcotic requirements, postoperative hypertension or postoperative nausea/vomiting. CONCLUSIONS: The remifentanil based anaesthetic was associated with a significantly slower HR than the fentanyl based anaesthetic. The clinical implications of the slower HR during remifentanil anaesthesia could be important and should be investigated.

Analgesics, Opioid↗
PubMed2003

Validation of the bispectral index monitor during conscious and deep sedation in children.

UNLABELLED: In this study, we tested the validity of the bispectral index (BIS) monitor during conscious and deep sedation of children by comparing it with the University of Michigan Sedation Scale (UMSS), a validated observational pediatric sedation scale. Eighty-six children <12 yr of age were enrolled in this observational study. The subjects underwent conscious or deep sedation administered by non-anesthesiologists for diagnostic or therapeutic procedures in four departments in a children's hospital. Sedation medications varied among departments and were not controlled by the study protocol. An independent observer derived a UMSS score at 10-min intervals for 1 h during sedation; personnel administering sedation medications and performing the procedures were blinded to the BIS and UMSS scores. Significant correlation between BIS scores and UMSS scores was found (r = -0.704, P < 0.0001), including in subjects <6 mo of age (n = 6) (r = -0.761, P < 0.001). Poor correlation was found when ketamine or an oral combination of chloral hydrate, hydroxyzine, and meperidine were used for sedation. We conclude that BIS correlates well with UMSS scores and may be a valid measure of conscious and deep sedation in children. IMPLICATIONS: We compared bispectral index scores with a validated observational scale of conscious and deep sedation in children and found significant correlation. We conclude that the bispectral index may be a valid measurement of depth of sedation in children.

Administration, Oral↗
PubMed2002

Duration of preoperative fast correlates with arterial blood pressure response to halothane in infants.

UNLABELLED: In this study, we sought to determine whether the duration of preoperative fasting affects the decrease in blood pressure observed in infants and children during halothane anesthesia. Two-hundred-fifty pediatric patients were divided into 5 age groups: term neonates (n = 50), 1-6 mo (n = 50), 6-24 mo (n = 50), 2-6 yr (n = 50), and 6-12 yr (n = 50). After anesthetic induction with halothane, end-tidal halothane was maintained at 2 minimum alveolar anesthetic concentration (MAC) for 10 min to allow myocardial uptake. Patients were grouped by duration of preoperative fast (0-4 h, 4-8 h, 8-12 h, and >12 h). Changes in heart rate and systolic (SAP) and mean (MAP) arterial blood pressure from preinduction to 2 MAC were compared among fasting groups within each age group. In the 1- to 6-mo age group, the changes in SAP and MAP were significantly greater in infants fasting 8-12 h than in those fasting 0-4 h (SAP, -51 mm Hg versus -31 mm Hg, respectively; MAP, -48 mm Hg versus -32 mm Hg; P < 0.05). No statistically significant differences were noted in the older age groups. The results of this study demonstrate that prolonged preoperative fasting is associated with a greater decrease in blood pressure in infants. This exacerbation of the already significant hemodynamic depression observed in infants during halothane anesthesia underscores the importance of adherence to published fasting guidelines. IMPLICATIONS: We studied changes in blood pressure during halothane anesthesia in infants and children and found that blood pressure decreased to a greater extent in infants who fasted for longer than 8 h before surgery. This exacerbation of the already significant hemodynamic depression observed in infants during halothane anesthesia underscores the importance of adherence to published fasting guidelines.

Anesthetics, Inhalation↗