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Biomedical subjects

U Borg

Publications and source records attributed to U Borg.

At least 19 recordsLinked to original sources
PubMed2000

Interhospital transport of the extremely ill patient: the mobile intensive care unit.

BACKGROUND: Critically ill patients may require specialized care that is offered only at tertiary referral centers. As regionalization and specialization of critical care become more common, transportation of critically ill patients must be refined. Transportation of critically ill patients within a hospital, much less outside the hospital, is often deemed unsafe because of medical instability. We report, here, our results from 2 yrs' experience of transporting extremely ill patients with respiratory failure via a ground critical care transport service. METHODS: A mobile intensive care unit was equipped and staffed to nearly recreate the intensive care environment. Staffing included a physician, nurse, respiratory therapist, and driver--all with extensive critical care experience. The mobile intensive care unit was equipped with a full pharmacy, advanced ventilatory equipment, and capability for full invasive hemodynamic monitoring. Data were analyzed by retrospective review. The predicted mortality rate, based on Pao2/Fio2 ratios, was compared with the actual mortality rate. RESULTS: During a 2-yr period, 39 critically ill patients were transported. Thirty-six of the 39 were candidates for extracorporeal lung assist, with a mean positive end-expiratory pressure requirement of 15.9, a mean Fio2 requirement of .93, and a mean Pao2/Fio2 ratio of 59.8. Pulmonary arterial catheters and peripheral arterial catheters were in place in 66.6% and 72% of patients, respectively. Vasoactive medications were being infused in 56%, and 74% were receiving medical paralytics. One patient died during movement from the bed to the transport gurney. Other than one episode of transient hypotension, there were no complications or untoward outcomes related to transport. Unique therapeutic interventions were performed at the receiving facility on 34 of 39 patients. The predicted mortality rate, based on indicators of lung dysfunction, was 68% to 100%; the actual subsequent hospital mortality rate was 43%. CONCLUSIONS: When a mobile intensive care unit is properly staffed and equipped and patient stabilization is performed before transfer, severely ill patients with respiratory failure can be transferred safely. For patients with respiratory failure, there may be a survival advantage in transfer to regional centers of expertise.

Adult↗
PubMed1998

Acute respiratory distress syndrome: estimated incidence and mortality rate in a 5 million-person population base.

BACKGROUND: Various estimates of the incidence and mortality rate of the acute (adult) respiratory distress syndrome (ARDS) have been published. The studies that led to those estimates were based on relatively small patient populations and employed variable diagnostic identifiers of ARDS. The purpose of this study was to estimate the incidence of ARDS and its mortality rate from a large database to which refined diagnostic criteria were applied. We conducted a retrospective review of all hospital discharges over a 4-year period, using screening criteria designed to select patients with ARDS. Discharges from all acute care hospitals in the state of Maryland were reviewed using a computer database from the Health Services Cost Review Commission (HSCRC). Patients >/= 12 years of age were included. Screening criteria consisted of ICD-9 codes 518.5 and 518.82 cross-referenced with procedural codes for ventilatory support (96.70, 96.71 and 96.72). Data were normalized to the number of cases per 100,000 people. RESULTS: During the 4-year study period there were 2,501,147 hospitalizations. Applying the ICD-9 ARDS criteria yielded lower and upper limits of 159-205, 439-568, 531-694 and 529-720 cases of ARDS for 1992, 1993, 1994 and 1995, respectively. Normalizing for a population of 5 million yields yearly lower and upper limit rates of 3.2-4.2, 8.8-11.4, 10.6-13.8 and 10.5-14.2 cases of ARDS per 100,000 people. Mortality upper and lower limit rates based upon the same duration, admissions and population were 38-49%, 39-52%, 36-47%, and 36-49%, respectively. CONCLUSIONS: The incidence of ARDS in Maryland is in the range of 10-14 cases per 100,000 people. The ARDS mortality rate is 36% to 52%, similar to that calculated in previous studies.

Journal Article↗
PubMed1995

Too sick to move?

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Critical Care↗
PubMed1991

Efficacy of continuous arteriovenous hemofiltration with dialysis in patients with renal failure.

OBJECTIVE: To document the efficacy of continuous arteriovenous hemofiltration with dialysis following renal failure, without protein restriction, and to explore the magnitude and clinical applications of total daily urea clearance. DESIGN: A noncomparative, descriptive account of a case series. Data were collected prospectively and analyzed retrospectively. SETTING: A tertiary care facility in a statewide emergency medical services system. PATIENTS: Twenty-eight patients with renal failure were supported by continuous arteriovenous hemofiltration with dialysis in a critical care unit during a 14-month period (21 patients with multitrauma; three patients with soft tissue infections; and four patients with multisystem organ failure who had been transferred from other hospitals). Renal failure was most commonly due to multisystem organ failure or associated with adult respiratory distress syndrome. RESULTS: Continuous arteriovenous hemofiltration with dialysis days totaled 308 (mean 10.9). All patients received full protein alimentation (mean protein load 131 g/day). The blood urea nitrogen concentration was controlled, generally to 40 to 75 mg/dL (14.3 to 26.7 mmol/L) within 3 to 5 days. Total daily urea clearance ranged from 15 to 21 g/day. Five (18%) of the 28 patients survived. CONCLUSION: Continuous arteriovenous hemofiltration with dialysis appears to be effective for the control of blood urea nitrogen and clearance of urea. This modality also permits full protein alimentation. Total daily urea clearance can be calculated easily and may have important clinical uses and implications.

Adult↗
PubMed1990

Efficacy of pressure support ventilation dependent on extravascular lung water.

Continuous positive-pressure ventilation and PSV were compared prospectively in patients at a surgical intensive care unit. All patients suffered from mild to moderate ARI (PaO2/FIO2 of 125 to 350 mm Hg). The patients were randomly assigned to a PSV group (n = 28) or a control group with continued CPPV (n = 27). The usual hemodynamic and oxygenation variables, ITBV, and extravascular lung water (ETV) were assessed before and six hours after switching to PSV. The changes (d) of PaO2/FIO2, RI, and P(A-a)O2 were used for evaluation of the effect of PSV. Significant correlations were found between the ETV(CPPV) and dPaO2/FIO2 (r = -0.672), ETV(CPPV) and dRI (r = 0.722), and ETV(CPPV) and dP(A-a)O2 (r = 0.601), which led to the conclusion that the level of ETV determined the efficacy of PSV. In the subgroup with ETV less than 11 ml/kg (n = 15), PSV significantly improved PaO2/FIO2 (248 to 286 mm Hg), RI (1.55 to 1.22), ITBV (801 to 888 ml/m2), cardiac index (4.21 to 4.76 L/min.m2), stroke index (42.2 to 48.1 ml/m2), and oxygen delivery (735 to 833 ml/min.m2). In the subgroup with ETV greater than 11 ml/kg (n = 13), PSV caused a significant deterioration of PaO2/FIO2, RI, and intrapulmonary shunt. It is concluded that in patients with moderate ARI in whom ETV is almost normal, PSV is superior to CPPV, and the efficacy of PSV is independent of the level of oxygenation during CPPV.

Adult↗
PubMed1985

Quantification of asymmetric lung pathophysiology as a guide to the use of simultaneous independent lung ventilation in posttraumatic and septic adult respiratory distress syndrome.

The management of impaired respiratory gas exchange in patients with nonuniform posttraumatic and septic adult respiratory distress syndrome (ARDS) contains its own therapeutic paradox, since the need for volume-controlled ventilation and PEEP in the lung with the most reduced compliance increases pulmonary barotrauma to the better lung. A computer-based system has been developed by which respiratory pressure-flow-volume relations and gas exchange characteristics can be obtained and respiratory dynamic and static compliance curves computed and displayed for each lung, as a means of evaluating the effectiveness of ventilation therapy in ARDS. Using these techniques, eight patients with asymmetrical posttraumatic or septic ARDS, or both, have been managed using simultaneous independent lung ventilation (SILV). The computer assessment technique allows quantification of the nonuniform ARDS pattern between the two lungs. This enabled SILV to be utilized using two synchronized servo-ventilators at different pressure-flow-volumes, inspiratory/expiratory ratios, and PEEP settings to optimize the ventilatory volumes and gas exchange of each lung, without inducing excess barotrauma in the better lung. In the patients with nonuniform ARDS, conventional ventilation was not effective in reducing shunt (QS/QT) or in permitting a lower FIO2 to be used for maintenance of an acceptable PaO2. SILV reduced per cent v-a shunt and permitted a higher PaO2 at lower FIO2. Also, there was x-ray evidence of ARDS improvement in the poorer lung. While the ultimate outcome was largely dependent on the patient's injury and the adequacy of the septic host defense, by utilizing the SILV technique to match the quantitative aspects of respiratory dysfunction in each lung at specific times in the clinical course, it was possible to optimize gas exchange, to reduce barotrauma, and often to reverse apparently fixed ARDS changes. In some instances, this type of physiologically directed ventilatory therapy appeared to contribute to a successful recovery.

Adolescent↗
PubMed1984

Computer-based evaluation of cardiopulmonary function for the optimization of ventilatory therapy in the adult respiratory distress syndrome.

A computer based evaluation system has been developed for the assessment of respiratory pressure flow dynamics, pulmonary gas exchange and ventilation perfusion interrelationships. This system is based on the acquisition of primary data on-line from intubated and ventilated patients consisting of airway pressures, ventilatory flows and mass spectrometric quantification of inspired and expired gas concentrations. The system has been applied to the study of patients with the adult respiratory distress syndrome (ARDS) following trauma and/or sepsis. The programs developed for evaluation of these data permit an interactive graphic capability to be used by the physician or the respiratory technician in a specific patient to determine the nature of the abnormalities in respiratory function. By use of this system for quantification of the extent and complications of the ARDS condition the specific ventilatory or cardiodynamic therapy can be tailored to meet the patient's physiologic needs. Techniques for optimization of conventional ventilator therapy are described and its application to the specific instances of combined high frequency ventilation or differential lung ventilation are presented. The clinical experience with this unit in a major trauma center suggests that quantitative analysis of an individual patients' respiratory dysfunction permits a precise, accurate and more effective approach to determining corrective therapy in ARDS.

Computers↗
PubMed1984

Regional organ blood flow during high-frequency positive-pressure ventilation (HFPPV) and intermittent positive-pressure ventilation (IPPV).

The effect of high-frequency ventilation (HFV) on cerebral blood flow (CBF) at normal and elevated intracranial pressure (ICP) was compared with flows measured under the same conditions during intermittent positive pressure ventilation (IPPV). Renal, lung (bronchial artery supply), and cardiac blood flows also were measured during HFV and compared with flows observed during IPPV. Measurements were made in canines with stable hemodynamic variables and arterial CO2 and O2 tensions in the normal range, CBF during HFV was comparable to the CBF during IPPV. Following an increase in ICP to a mean of 44 +/- 18 mmHg (SD), mean CBF decreased to 22.5 +/- 11 ml . 100 g-1 . min-1 (SD) during IPPV and 21.7 +/- 13.2 ml . 100 g-1 . min-1 (SD) during HFV. No statistical differences could be noted in regional or global flow as a function of ventilatory mode. Renal, lung (bronchial artery supply), and cardiac blood flows also showed no statistical variation between HFV and IPPV. Ventilator-synchronous fluctuations in ICP observed during IPPV were reduced during HFV at normal ICP and eliminated by HFV at elevated ICP.

Animals↗
PubMed1977

Physiologic evaluation of the HFPPV pneumatic valve principle and PEEP. An experimental study.

In experiments in dogs the ventilatory and circulatory conditions prevailing with the ventilatory pattern in high-frequency positive-pressure ventilation (HFPPV) were investigated with use of a pneumatic valve principle and a ventilator system of an "open" character. Keeping the gas input constant the importance of insufflation frequency and insufflation time and the reactions to various levels of positive end-expiratory pressure (PEEP) were investigated in terms of changes in arterial pH, Pco2 and Po2. With the volumes of delivered gas kept constant, an increasing insufflation frequency from 60 to 100 per min gave a parallel decrease in tidal volume accompanied by lower maximum intratracheal pressures and a significant decrease in alveolar ventilation. Also taking into account the possibilities of inducing a suppression of the spontaneous respiration, higher ventilatory frequencies than 60 per min do now seem to introduce any further advantages. Including the associated effects on cardiac output and venous admixture, the cardio-pulmonary and circulatory parameters studied did not show any substantial changes with PEEP levels below 7.5--10 cm H2O. Thus the level of PEEP, which often is part of the ventilatory pattern in HFPPV, does not seem to have any untoward influence on the circulation (stroke volume, cardiac output, total peripheral vascular resistance) and oxygen transport (arterial oxygen content and oxygen flux) in normovolaemic dogs.

Animals↗
PubMedDate not supplied

Life-threatening acute systemic lupus erythematosus: survival after multiple extracorporeal modalities: a place for the multipotential extracorporeal service.

Diffuse alveolar hemorrhage secondary to systemic lupus erythematosus (SLE) may cause life-threatening respiratory failure and may be associated with multiple organ failure. Extensive support may be necessary to sustain life while systemic therapy becomes effective. We report here a patient with profound respiratory failure secondary to SLE associated with multiorgan failure, who was supported with veno-arterial extracorporeal lung assist (ECLA), veno-venous ECLA, and multiple continuous renal replacement therapies during plasmapheresis. The full spectrum of extracorporeal life support and treatment modalities was performed seamlessly by a single service within the critical care department.

Acute Disease↗