A simple, cost-effective method of preventing laryngoscope handle contamination.
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Equipment Contamination↗
Biomedical subjects
M J Tobin
Publications and source records attributed to M J Tobin.
Multidisciplinary teams and childhood visual impairment: a study of two teams.
Multidisciplinary teams are generally viewed as beneficial in the management of the visually impaired child, yet little is known about them. Two teams were studied. Team A had well-defined functions relating to identification of visually impaired children, co-ordination of services and liaison. Team B had a more general aim of sharing information on a range of ophthalmic issues other than visual impairment. By comparing the two teams, we conclude that a multidisciplinary team is more likely to be effective if it draws its membership from a range of appropriate professions and its functions are focused. Benefits of teams include increased and earlier referral, improved interdisciplinary liaison and collaboration, and speedier and more appropriate implementation of services. Lack of time to participate, particularly by medical personnel, is a problem.
Child↗
Pattern of recovery from diaphragmatic fatigue over 24 hours.
The rate of recovery from diaphragmatic fatigue beyond 1 h is unknown. To investigate this question, we studied 12 healthy subjects and measured transdiaphragmatic twitch pressure (Pditw) using magnetic stimulation of the phrenic nerves. Measurements were obtained at baseline and after a fatigue protocol consisting of inspiratory resistive loading in which the subjects generated 60% of maximal transdiaphragmatic pressure until task failure. At baseline, Pditw was 38.9 +/- 1.1 (SE) cmH2O and fell to 25.1 +/- 0.6 cmH2O 10 min after the conclusion of the fatigue protocol (P < 0.01). Pditw increased to 27.6 +/- 0.9, 31.6 +/- 1.1, and 32.7 +/- 1.2 cmH2O 1, 8 and 24 h, respectively, after the conclusion of the fatigue protocol; the 24-h value was significantly lower than baseline (P < 0.01). The nadir in Pditw after the protocol was delayed by 10 min. In separate experiments, we showed that this delay was probably due to the development of twitch potentiation as a result of forceful diaphragmatic contractions during the fatigue protocol. In conclusion, induction of diaphragmatic fatigue with this experimental protocol produced a marked decrease in diaphragmatic contractility that persisted for at least 24 h.
Action Potentials↗
Bronchodilator delivery by metered-dose inhaler in ventilator-supported patients.
The optimal dose and technique for administration of bronchodilators with a metered-dose inhaler (MDI) in mechanically ventilated patients have not been established. We studied the efficacy and safety of 10 puffs (90 micrograms/puff) of albuterol administered by an MDI in seven mechanically ventilated patients with chronic obstructive pulmonary disease (COPD). Rapid airway occlusions at constant flow inflation were performed before and at 5-min intervals after administration of albuterol for 60 min. Significant decreases in maximum (Rrsmax; p < 0.01) and minimum inspiratory resistance (Rrsmin; p < 0.01) were present at 5 min and persisted for 60 min after administration of albuterol (p < 0.01 for both parameters). Rrsmax indicates maximal inspiratory resistance while Rrsmin represents the ohmic flow resistance. Intrinsic positive end-expiratory pressure decreased significantly (p < 0.05) 15 min after albuterol administration. Heart rate, blood pressure, and arterial oxygenation did not show significant change after albuterol. In summary, 10 puffs of albuterol given by an MDI and spacer produced significant bronchodilation in ventilator-supported patients with COPD, without producing side effects. In conclusion, higher doses of albuterol given by an MDI and spacer could be used routinely in mechanically ventilated patients with COPD.
Administration, Inhalation↗
Variability of patient-ventilator interaction with pressure support ventilation in patients with chronic obstructive pulmonary disease.
In 12 patients with chronic obstructive pulmonary disease (COPD) receiving pressure support ventilation (PSV), we studied the variability of respiratory muscle unloading and defined its physiologic determinants using a modified pressure-time product (PTP). Inspiratory PTP/min decreased as PSV was increased (p < 0.001), but there was considerable interindividual variation: coefficients of variations of up to 96%. On multiple linear regression analysis, 73 to 83% of the variability in inspiratory PTP was explained by inspiratory resistance, minute ventilation, and intrinsic positive end-expiratory pressure. Taking an inspiratory PTP/min of < 125 cm H2O.sec/min to represent a desirable level of inspiratory effort during PSV, a respiratory frequency of < or = 30 breaths/min was more accurate than a tidal volume > 0.6 L in predicting this threshold (p < 0.001). At PSV of 20 cm H2O, expiratory effort, quantitated by an expiratory PTP, was clearly evident in five patients before the cessation of inspiratory flow, signifying that the patient was "fighting" the ventilator; of note, these five patients had a frequency of < or = 30 breaths/min. In conclusion, patient-ventilator interactions in patients with COPD are complex, and events in expiration need to be considered in addition to those of inspiration.
Aged↗
Interrelationship of breath components in neighboring breaths of normal eupneic subjects.
To determine the fraction of variational activity that is correlated on a breath-to-breath basis from uncorrelated random fluctuations, we performed autocorrelation analysis in 33 normal subjects during resting breathing. A calibrated inductive plethysmograph was used to nonobtrusively record 700 breaths in each subject. The group mean autocorrelation coefficients at a lag of 1 breath for each of the three primary breath components, tidal volume (VT), inspiratory time (TI), and expiratory time (TE), were significantly different from zero (p < 0.001). The autocorrelation coefficients for VT, 0.295 +/- 0.148 (SD), and TE, 0.259 +/- 0.121, were greater than that for TI, 0.201 +/- 0.135 (p < 0.001 and p < 0.01, respectively). The autocorrelation coefficients for each breath component remained significant for approximately 3 consecutive breaths (p < 0.001), indicating the presence of "short-term memory." Cross-correlation analysis revealed significant interrelationships (p < 0.001) for all component irrespective of which component was leading or following, with the exception of the pairing of VT in the leading breath and TI in the subsequent breath. In conclusion, in resting healthy subjects breath components display considerable breath-to-breath variability that is not completely random in nature, but which, instead, has a significant fraction of structured correlated variational activity.
Adult↗
Oxygen takes the breath away: old sting, new setting.
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Blood Gas Analysis↗
Using physiologic end points to assess innovations in mechanical ventilation.
It is our view that new ventilatory methods should be withheld from clinical practice until there has been adequate evaluation of their effect on physiologic variables and the link to long-term outcomes has been established. In the past, premature and over-enthusiastic acceptance of ventilatory strategies may have resulted in patient discomfort and even harm, and this can be minimized by a more careful evaluation of the physiologic effects of such innovations before their acceptance into clinical practice.
Diffusion of Innovation↗
Pathophysiology of failure to wean from mechanical ventilation.
Weaning patients from mechanical ventilation constitutes a major portion of the workload in an intensive care unit, as over 40% of total ventilator time is consumed by the weaning process. Several pathophysiological mechanisms may be responsible for weaning failure, but the precise role of each is incompletely understood. Patients who fail a weaning trial commonly develop hypercapnia, which appears to be due to decreased tidal volume rather than a primary decrease in respiratory drive. Respiratory muscle performance is impaired as a result of dynamic hyperinflation and paradoxic motion of the rib cage and abdomen. Worsening of pulmonary mechanics will cause further embarrassment of the respiratory muscles. However, the clinical importance of respiratory muscle fatigue remains unclear. Afferent stimuli arising in the lung parenchyma, respiratory muscles, or as a consequence of impaired gas exchange will be transmitted to the respiratory control centers and result in severe dyspnea in patients who fail a weaning trial.
Abdomen↗
Weaning patients from mechanical ventilation using gastric pH.
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Gastric Acidity Determination↗
Patterns of professional involvement with parents of visually impaired children.
The authors sampled a range of professionals who deal with visually impaired children to determine how they involve parents in the management of these children. There were 10 peripatetic teachers, eight ophthalmologists, six paediatricians, three social workers, three headmasters of special schools for visually impaired children, and two educational psychologists. Ophthalmologists were the least likely to attend multidisciplinary case discussions, involve parents in discussions or give parents written information. About half the sample presented an optimistic picture, but almost half considered that parents needed more support, more information or improved communication between professionals. Two complementary solutions are proposed: the development of multidisciplinary teams and the use of a 'key person' or 'case manager' to co-ordinate services.
Adult↗
Use of flow-volume curves in detecting secretions in ventilator-dependent patients.
A noninvasive means of detecting airway secretions in ventilator-dependent patients is desirable because endotracheal suctioning can result in life-threatening complications. In a patient who had copious secretions, we observed a sawtooth pattern on his flow-volume curve that disappeared after suctioning. Accordingly, we systematically examined the usefulness of a sawtooth pattern on flow-volume curves in detecting secretions in ventilator-dependent patients and compared its accuracy with clinical examination. Flow-volume curves were recorded in 50 ventilator-dependent patients over 1 min of spontaneous breathing. In 15 of these patients, clinical examination was performed by three clinicians to determine its accuracy in detection of secretions. Endotracheal suctioning was then performed to determine the presence or absence of secretions. Subsequently, the flow-volume curves of all 50 patients were played back on a video screen, and three observers, who were unaware of the results of suctioning, made a decision regarding the presence or absence of a sawtooth pattern. The sensitivity of the sawtooth pattern in detecting secretions ranged from 0.76 to 0.86, and specificity ranged from 0.86 to 0.90. The likelihood ratio of a positive test ranged from 5.55 to 7.97, whereas the likelihood ratio of a negative test ranged from 0.16 to 0.27. Interobserver agreement, assessed by the kappa statistic, was excellent: 0.76, 0.76, and 0.84. In the subgroup of patients evaluated by both clinical examination and flow-volume curve analysis, clinical examination was less accurate in 11 of the 15 patients. In conclusion, detection of a sawtooth pattern strongly suggests the presence of secretions, and the absence of this pattern suggests that secretions are unlikely to be present.
Acute Disease↗
Urine hydrogen peroxide during adult respiratory distress syndrome in patients with and without sepsis.
BACKGROUND: The lung injury in adult respiratory distress syndrome (ARDS) has been associated with increased expiratory hydrogen peroxide (H2O2) concentrations. Furthermore, patients with sepsis and ARDS are reported to have greater serum scavenging of H2O2 than patients with ARDS only. We hypothesized that the systemic presence of H2O2 would be detectable in the urine of these two groups of patients and that, in the case of ARDS sepsis, the relative contribution of each disease to the production this analyte would be discernible. Accordingly, we used an in vitro radioisotope assay to follow the weekly course of urine H2O2 levels in ARDS patients with and without sepsis, and in samples from control non-ARDS patients with sepsis with indwelling urinary catheters and in samples provided by healthy volunteers. METHODS: Thirty patients with ARDS were included in the study: 23 had sepsis and 7 were sepsis free. An indwelling catheter was used to collect urine from each patient over a 24-h period, first within 48 h of ICU admission and then every seventh day over the course of their illness. Urine H2O2 was measured by competitive decarboxylation of 1-14C-alpha-ketoglutaric acid by H2O2. Urine samples were provided by 20 healthy volunteers while, in 10 non-ARDS patients with sepsis, urine was collected over one 24-h period following a 5-day minimum with an indwelling urinary catheter. RESULTS: Urine H2O2 concentration in healthy control subjects (88 +/- 4 mumol/L) and non-ARDS patients with urinary catheters (96 +/- 5 mumol/L) was not significantly different. During the first 48 h in the ICU, urine H2O2 in patients with ARDS only (295 +/- 29 mumol/L) was significantly lower (p < 0.05) than patients with ARDS and sepsis (380 +/- 13 mumol/L); however, the lung injury scores of these two groups did not differ. Furthermore, within the first 48 h, the urine H2O2 of the patients with ARDS and sepsis who did not survive (427 +/- 19 mumol/L; n = 7) was significantly higher than that in patients who survived sepsis (352 +/- 14 mumol/L; n = 15). Thereafter, the lung injury scores and urine H2O2 levels of the nonsurvivor ARDS-sepsis group remained significantly higher compared with the other two groups. At lung injury scores of 3 and 2, regardless of days in ICU, the patients with ARDS only had significantly lower urine H2O2 (266 +/- 30 mumol/L and 167 +/- 24 mumol/L, respectively) compared with the survivor ARDS-sepsis group (376 +/- 19 mumol/L and 250 +/- mumol/L). When the patients with ARDS (both ARDS only and with sepsis) recovered, their urine H2O2 concentration did not differ from the control groups (healthy donors and patients without ARDS). CONCLUSION: Lung injury scores did not differentiate patients with ARDS and sepsis from patients with ARDS only during the first 10 days in the ICU; however, urine H2O2 levels were significantly greater in the patients with ARDS and sepsis. Moreover, despite no initial difference in lung injury, patients who did not survive ARDS and sepsis had consistently greater urine H2O2 concentration than patients who survived sepsis. The urine H2O2 level in the ARDS-only group was about 70 percent of the level in the survivor ARDS and sepsis group, suggesting that ARDS alone is the major contributor to the H2O2 oxidant processes during combined ARDS and sepsis. Furthermore, these studies demonstrate that urine H2O2 may be a useful analyte to differentiate the severity of oxidant processes in patients with ARDS and sepsis albeit the prognosis appears to be survival or nonsurvival.
Adolescent↗
Modes of mechanical ventilation and weaning. A national survey of Spanish hospitals. The Spanish Lung Failure Collaborative Group.
Little information exists regarding the proportion of patients treated with mechanical ventilation in intensive care units (ICUs), their underlying disease states, the modes of ventilation used, duration of ventilator support, methods and time required for weaning, and mortality in these patients. We carried out a cross-sectional multicenter study in 47 medical-surgical ICUs in Spain to investigate these issues in 290 patients who required mechanical ventilation for at least 24 hs. Relative frequency of different modes was as follows: assist-control ventilation (AC), 55%; synchronized intermittent mandatory ventilation (SIMV), 26%; pressure support ventilation (PSV), 8%; SIMV plus PSV, 8%; pressure-controlled ventilation (PCV), 1%; and continuous positive airway pressure (CPAP), 2%. Overall duration of mechanical ventilation was 27.1 +/- 1.1 (SE). A variety of techniques were used for weaning: T-tube trials, 24%; SIMV, 18%; PSV, 15%; SIMV plus PSV, 9%; and some combination of two or more methods in succession in 33% of the patients. Time required for weaning using a combination of SIMV and PSV was longer (17.8 days) than with other techniques (about 5 days, p < 0.01). Time between initiation of weaning and removal of mechanical ventilation accounted for 41% of total ventilator time and was particularly high (59%) in patients with chronic obstructive pulmonary disease. Overall mortality rate was 34%, and it was higher in patients who were ventilated for 1 to 10 days than in those ventilated for a longer time. Despite the availability of several new modes of ventilator support, older modes such as AC and SIMV were more commonly used. Weaning constitutes a large portion of total ventilator time, and thus, measures that expedite the weaning process should markedly decrease the duration of mechanical ventilation.
APACHE↗
Predicting the unpredictable: issues for output-based funding in psychiatric services.
In this study a number of important issues relating to diagnosis related groups and psychiatry are highlighted. Retrospective analysis of admissions to a rural psychiatric admission unit was undertaken utilising two differing approaches to statistical analysis. Results revealed that diagnosis alone is not highly predictive of cost. However, when linked to other variables, greater explanation in variation of length of stay was achieved. Data from social variables yielded sufficiently interesting results to warrant further investigation. The authors conclude by reporting the resultant groups from the classification analysis and offer some suggestions for further research.
Adult↗
What's behind the fight for female patients?
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Female↗
Inquiries at Lakeside and Aradale Hospitals: lessons and advances?
The release of reports of inquiries into two related psychiatric hospitals (Lakeside and Aradale) in Victoria occurred in 1991. These inquiries identified deficiencies in patient care standards and organisational dynamics. Knowledge of institutional dysfunction was available from similar Australian and overseas inquiries but nonetheless this knowledge had not prevented organisational inertia and decline in these two psychiatric hospitals. This paper examines the possible contribution of a failed medical hegemony model to organisational dysfunction and discusses organisational life-cycles. It reaches the conclusions that politically motivated inquiries do not achieve long term positive outcomes and that there is a need for academic research into the organisation of psychiatric services and staff productivity and morale.
Burnout, Professional↗