The PB3300 intraarterial blood gas monitoring system

Continuous intraarterial blood gas (IABG) monitoring is in clinical use both in the operating room and intensive care unit. This technology uses miniature, optically-based sensors that can be placed into a patient's artery. The arterial blood gas values are transduced into an optical signal that is measured by a bedside monitor on which the values are displayed. In this paper, we describe the operating principles of the PB3300 Intra-Arterial Blood Gas Monitoring System (Puritan-Bennett Corporation, FOxS Division, Carlsbad, CA). Topics include the principles of fluorescent determinations of pH,PCo ₂, andPO ₂; the optical path of the PB3300; system calibration; dye layer geometry; and clinical operation. The accuracy, precision, and drift of the system measuring tonometered aqueous standards are reported. The following values were noted for eight sensors sending data to eight monitors: system bias and precisions of 0.00±0.02 pH at a pH of 7.40, –2.5±1.5 mm HgPCo ₂ at aPCo ₂ of 40 mm Hg, and 3.3±1.3 mm HgPO ₂ at aPO ₂ of 80 mm Hg.

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Abstrakt Die kontinuierliche intraarterielle Blutgasüberwachung (IABG) wird klinisch sowohl im OP als auch auf der Intensivstation eingesetzt. Hierbei werden miniaturisierte, optische Sensoren angewandt, die sich direkt in der Arterie des Patienten plazieren lassen. Die Blutgaswerte werden in optische Signale umgesetzt und von einem bettseitigen Monitor gemessen und angezeigt. In dieser Arbeit beschreiben wir das Funktionsprinzip des Intra-Arteriellen Blutgasanalysesystems PB3300 (Puritan-Bennett Corporation, FOxS Division, Carlsbad, CA). Themen sind die Grundlagen der Bestimmung von pH, PCO2 und PO2 mittels Fluoreszenz; die optische Übertragung des PB3300; die Kalibrierung des Systems; die Geometrie der Farbschichten und der Einsatz in der Klinik. Die Genauigkeit, Auflösung und Drift des Systems bei der Messung von tonometrischen wässrigen Standards wird beschrieben. Die folgenden Werte ergaben sich aus einer Meßreihe mit 8 Sensoren, die an 8 Monitore angeschlossen waren (jeweils Bias, Streuung und Sollwert): 0.00±0.02 pH bei 7.40 pH, –2.5±1.5 mmHg PCO2 bei 40 mmHg PCO2 und 3.3±1.3 mmHg PO2 bei 80 mmHg PO2.

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Resumen La monitorizaciòn continua de gases intraarteriales tiene uso clinico, tanto en el pabellòn de operaciones como en la unidad de cuidados intensivos. Esta tecnologia utiliza sensores miniatura de tipo òptico que pueden ser introducidos en una arteria del paciente. Los valores de gases arteriales son transducidos en forma de señal òptica que es medida al lado de la cama del paciente por un monitor que presenta los valores numéricos. En este trabajo, describimos los principios de operaciòn del PB3300 Intra-Arterial Blood Gas Monitoring System (Puritan-Bennett Corporation, FOxS Division, Carlsbad, CA). Los temas incluyen los principios de determinaciones fluorescentes de pH, PCO₂, and PO₂; la via òptica del PB3300; calibraciòn del sistema; geometria de la capa de colorante; y la operaciòn clinica. Se presentan la exactitud, precisiòn, y deriva (drift) del sistema, midiendo soluciones acuosas de tonometrìa estàndar. Los siguientes valores fueron registrados para ocho sensores enviando informaciòn a ocho monitores: los sesgos del sistema y las precisiones fueron de 0.00±0.02 pH a pH 7.40, –2.5±1.5 mmHg PCO₂ a PCO₂ 40 mmHg, y 3.3±1.3 mmHg PO₂ a PO₂ 80 mmHg.

     

Nurse/patient dependency — is it iatrogenic?

It is often assumed that nursing care is given in response to the patient's degree of incapacity. This study indicates that rather than nursing care arising as a response to patients' dependency, nursing care is producing dependency. A considerable proportion of the measured dependency of 168 elderly patients arose from the type of nursing care they received--it was iatrogenic. Task allocation nursing was found to be positively unhealthy for elderly long-stay patients, whilst individualized care (nursing process) was associated with lower patient dependency, a shorter hospital stay and a better chance of surviving the hospital stay. The findings demonstrate the inadequacy of nurse staffing formulas which are based on patient dependency. It is suggested that despite the rising numbers of very old people in the population, the elimination of nurse-induced dependency could reduce the level of dependency in geriatric wards.     

Reflection-on-practice: enhancing student learning

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The challenge of change in nurse education: traditionally trained nurses' perceptions of Project 2000

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Comparison of two warming interventions in surgical patients with mild and moderate hypothermia

Two interventions: a forced warm-air device (Bair-Hugger series 500, Augustine Medical Inc., Eden Prairie, MN, USA), group 1; and a standardized approach to the use of warmed blankets (group 2) are compared with the aim of enhancing thermoregulation in surgical patients with mild and moderate hypothermia in the immediate recovery period. One hundred and twenty patients in a post-anaesthetic care unit were systematically allocated to group 1 or group 2 so each group consisted of 110 participants. No significant differences were found between the groups in gender, age, time in surgery, use of warmed intravenous fluids or muscle relaxants, or type of surgery. After exclusion of orthopaedic patients, significant differences in the mean rewarming rates were found, with more rapid rewarming occurring within group 1 (the group rewarmed with a forced warm-air device, t = 2.15, df = 92, P = 0.03) compared with group 2. No significant differences were found in the mean rewarming time, or heat gain between groups, and subsequent power estimates were less than 0.80. This study supports improved rewarming rates in select surgical patients (with mild or moderate hypothermia) using the Bair-Hugger^TM compared with a standardized blanket rewarming intervention and identifies the need for patient comfort and cost-benefit analysis to be considered in future studies.     

A survey of current practice in skeletal pin site management

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