ABSTRACT
A comparison was made of arterial pressures measured invasively from a radial arterial cannula and non-invasively from the middle finger using the 2300 Finapres (Ohmeda) during induction and maintenance of anaesthesia. Digital outputs of both pressures were captured directly onto computer hard disk; data recorded during flushing of the arterial line were excluded from analysis. We studied 53 patients undergoing cardiac, major vascular and neurosurgical procedures; 17705 comparisons of systolic, diastolic and mean pressure were analysed. Overall correlations between Finapres and invasive pressures were poor (r = 0.82, 0.68 and 0.78 for systolic, diastolic and mean pressures, respectively). The Finapres exhibited a high level of accuracy and precision in some recordings. However, patient data sets showed marked variability in average pressure differences (invasive minus Finapres) when examined individually or grouped by operation type. Unexplained variations in pressure difference with time and absolute pressure were observed also. Whilst providing useful beat-to-beat information on arterial pressure trends, the Finapres cannot be recommended as a universal substitute for invasive arterial pressure monitoring.
Subject(s)
Anesthesia, General , Blood Pressure Determination/methods , Blood Pressure Monitors , Monitoring, Intraoperative/methods , Adult , Aged , Arteries/physiology , Blood Pressure/physiology , Catheterization, Peripheral , Female , Fingers/blood supply , Humans , Male , Middle Aged , Monitoring, Intraoperative/instrumentation , Regression Analysis , Time FactorsABSTRACT
To establish anesthesia with minimal respiratory and cardiovascular depression using propofol, the effects of varying the rate of delivery on anesthetic induction dose requirements and hemodynamic changes were studied in four groups of 20 patients each undergoing body surface surgery. All patients were premedicated with temazepam and received 1.5 micrograms/kg fentanyl 5 min before induction. Propofol was delivered at 50, 100, or 200 mg/min by the Ohmeda 9000 infusion pump (groups 1, 2, and 3, respectively) or by bolus of 2 mg/kg (group 4) until loss of verbal contact. Anesthesia was maintained thereafter with propofol infused at 6 mg.kg-1.h-1. Using slower infusion rates, induction took significantly longer (124, 92, 62, and 32 s in groups 1, 2, 3, and 4, respectively) and was achieved with significantly smaller doses of propofol (1.40, 1.96, 2.61, and 2.15 mg/kg in groups 1, 2, 3, and 4, respectively). Slow infusion (groups 1 and 2) caused less depression of systolic and diastolic blood pressure than rapid infusion (groups 3 and 4), but the differences were not statistically significant. Patients in groups 3 and 4 had significantly greater decreases in pulse rate and a greater incidence of apnea than did patients in group 1. There was no correlation between the size of the induction dose and subsequent maintenance requirements of propofol. The finding that the sleep dose of propofol is reduced at slower infusion rates has important practical and theoretical implications when considering the relative potencies of intravenous anesthetics.
Subject(s)
Propofol/administration & dosage , Adult , Anesthesia Recovery Period , Anesthesia, General , Consumer Behavior , Female , Hemodynamics/drug effects , Humans , Infusion Pumps , Infusions, Intravenous , Male , Middle Aged , Preanesthetic Medication , Propofol/blood , Propofol/pharmacology , Temazepam/administration & dosageABSTRACT
The Ohmeda 9000 syringe pump was developed in response to the need for an infusion apparatus to administer intravenous anaesthetic agents. It incorporates a bolus facility for the rapid, controlled delivery of loading infusions, or incremental dosing over a background maintenance infusion, and may be interfaced with a controller for computer-driven infusions. The Ohmeda 9000 pump has undergone bench testing and detailed evaluation in clinical practice using a variety of syringe sizes and makes. It is capable of accurate delivery over a range of infusion rates provided the recommended manufacturers' syringes are used with the appropriate pump setting. The pump was easy to use and reliable in clinical research and routine clinical practice. It should find its niche as the first genuinely 'anaesthetist-friendly' infusion pump.
Subject(s)
Anesthesia, Intravenous/instrumentation , Infusion Pumps , Anesthetics/administration & dosage , Equipment Design , Evaluation Studies as Topic , Humans , Infusion Pumps/standardsABSTRACT
Children presenting with advanced leukaemia and non-Hodgkin's lymphoma may develop life-threatening complications in the early stages of management. Major metabolic disturbances with encephalopathy, septicaemic shock, pneumonitis, massive haemorrhage, or the physical effects of tumour masses may on occasion warrant intensive therapy. Close liaison between paediatric oncologists, oncological surgeons, and anesthesiologists is essential in establishing admission criteria for such cases and in defining therapeutic end points in the event of multisystem failure. This paper discusses the principles of intensive care management of patients with haematological malignancies by considering two cases who developed the tumour lysis syndrome with respiratory and renal failure. A case associated with metabolic encephalopathy is also described.
Subject(s)
Abdominal Neoplasms/drug therapy , Burkitt Lymphoma/drug therapy , Intensive Care Units , Leukemia-Lymphoma, Adult T-Cell/drug therapy , Lymphoma/drug therapy , Tumor Lysis Syndrome/prevention & control , Anesthesiology , B-Lymphocytes , Child , Child, Preschool , Female , Humans , Male , Patient Care Team , Respiration, Artificial , Respiratory Insufficiency/therapy , Risk FactorsABSTRACT
Tumour lysis syndrome occurs when chemotherapy is started in children who present advanced lymphomas and leukaemias. Rapid cell lysis causes life-threatening metabolic derangements because of the release of intracellular potassium, phosphate and uric acid. An alkaline diuresis is commonly established before the start of chemotherapy to minimise uric acid and phosphate deposition within the kidney. Two cases are described where intravenous fluid loading resulted in acute pulmonary oedema, and the intensive care management of such cases is discussed. The improved outcome from increasingly aggressive chemotherapeutic regimens means that children with advanced tumours and organ failure may present for supportive therapy during the early stages of treatment. Close liaison between paediatric oncologists and intensive care staff is essential to establish admission criteria for patients at risk of these complications, and to define therapeutic end points in the event of multisystem failure.
Subject(s)
Critical Care , Diuresis , Pulmonary Edema/etiology , Tumor Lysis Syndrome/prevention & control , Antineoplastic Agents/administration & dosage , Child , Child, Preschool , Female , Humans , Infusions, Intravenous , Male , Time FactorsABSTRACT
The effect of diluting propofol in 5% dextrose on the incidence of i.v. injection pain was studied in 100 adult patients. Severe injection pain occurred in 32% (16 patients) who received undiluted propofol, compared with 10% (five patients) who received dilute propofol. We concluded that the dilution of propofol significantly reduced the incidence of severe pain during injection without increasing postoperative venous sequelae.