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Biomedical subjects

A Joseph Layon

Publications and source records attributed to A Joseph Layon.

18 recordsLinked to original sources
PubMed2006

Power of breathing determined noninvasively with use of an artificial neural network in patients with respiratory failure.

OBJECTIVE: To determine work of breathing per minute or power of breathing noninvasively (POB(N)) by using an artificial neural network (ANN) without the need for an esophageal catheter in patients with respiratory failure. DESIGN: Prospective study comparing the relationship between POB(N) and invasively measured power of breathing (POB(I)). SETTING: Intensive care unit of a university hospital. PATIENTS: Forty-five intubated adults (age, 51 +/- 11 yrs; weight, 71 +/- 18 kg; 28 males and 17 females) receiving pressure support ventilation (PSV). INTERVENTIONS: Data from an esophageal catheter and airway pressure/flow sensor were used to measure POB(I). A pretrained ANN provided real time calculation of POB(N). POB(I) and POB(N) were measured at various levels of PSV, ranging from 5 to 25 cm H(2)O. MEASUREMENTS AND MAIN RESULTS: POB(N) was highly correlated with POB(I) (r = 0.91; p < .002), and because POB(N) explained or predicted 83% of the variance in POB(I), it was considered a very good predictor (r(2) = 0.83; p < .002). Bias was negligible (0.00) and precision was clinically acceptable (2.2 J/min). CONCLUSIONS: POB can be calculated noninvasively with reasonable clinical accuracy for patients receiving ventilatory support by using an ANN. This method obviates the need for inserting an esophageal catheter and thus greatly simplifies measurement of POB. POB(N) may be a clinically useful tool for consideration when setting PSV to unload the respiratory muscles. Before considering its use in clinical practice, POB(N) would need to be incorporated within the context of load tolerance and shown to improve outcomes.

Female↗
PubMed2006

Symptom combinations associated with outcome and therapeutic effects in a cohort of cases with SARS.

Severe acute respiratory syndrome (SARS) is an infectious disease and some of its symptoms were clinically indistinguishable of those from similar diseases. This study aimed to find the symptom combinations associated with adverse outcome and the therapeutic effects in a cohort of patients with probable SARS retrospectively. In 2003, 123 SARS cases in Beijing were subjected to a strictly western medicine (WM) treatment, or a combined treatment (WM plus Herba houttuyniae injection, addition of individualized herbal treatments when necessary), of which 115 were followed till death or discharge; 8 were transferred and lost to follow-up. In both treatment groups, clinical manifestations were evaluated daily; development of signs and symptoms, and their possible relationship with outcome, were assessed. The relationships between these sign/symptom complexes and outcome under two treatment protocols were evaluated and differences were noted. Dynamic symptom combinations, dividing into the early, the medium-term and the durational symptom clusters, were identified as likely being related to the adverse outcomes of SARS (p < 0.05, p < 0.01). Compared with a strictly WM treatment, the combined treatment resulted in a longer hospital stay (p = 0.028), a non-statistically significant mortality rate decrease (combined treatment: 9.6% versus WM: 11.1%), and a significant improvement of arthralgia and myalgia (p < 0.05) in the early symptom cluster. Additionally, the combined protocol improved arterial oxyhemoglobin saturation significantly at day 22 (p < 0.05). In conclusion, the progress and outcome of SARS may be associated with specific temporal patterns of development in combination of several non-specific signs and symptom complexes, which are also helpful for evaluating the therapeutic effects on SARS patients.

Adolescent↗
PubMed2005

Oxidant injury occurs rapidly after cardiac arrest, cardiopulmonary resuscitation, and reperfusion.

OBJECTIVE: Investigations conducted in cellular models show that reperfusion of ischemic tissue is associated with a burst of reactive oxidant species within minutes after reperfusion. Oxidant injury may play a role in the poor outcome typical of people resuscitated from cardiac arrest. The objective of the present study was to determine the presence and timing of oxidant injury in an in vivo model of cardiac arrest. DESIGN: Randomized controlled. SETTING: University medical center laboratory. SUBJECTS: Domestic swine. INTERVENTIONS: We evaluated oxidant injury during and after 8 mins of cardiac arrest using a gas chromatography/mass spectrometry F2-isoprostane assay and compared these results with a matched control group. MEASUREMENTS AND MAIN RESULTS: Baseline mean arterial, venous, and brain tissue F2-isoprostane levels were not significantly different when the cardiac arrest group was compared with the control group. However, in the group subjected to cardiac arrest and cardiopulmonary resuscitation we found significant (p < .0006) two- to three-fold increases in venous and arterial F2-isoprostane levels, which peaked between 15 and 30 mins after reperfusion and returned to baseline within 90 mins (p < .0006). Overall mean (+/- SE) brain tissue F2-isoprostane levels increased significantly to 370 +/- 60 vs. 140 +/- 60 ng/g tissue in the cardiac arrest group compared with the control group (p = .026). CONCLUSION: This study shows that F2-isoprostane measurement could be used to assess oxidant injury in an animal model of cardiac arrest and that oxidant injury occurs rapidly after cardiac arrest and reperfusion.

Animals↗
PubMed2005

Utilization of intensive care resources in bariatric surgery.

BACKGROUND: Obese patients occasionally require either elective or emergency critical care services following bariatric surgery. We describe this subgroup of patients. METHODS: From July 1, 1991 to July 31, 2004, we performed 1,279 bariatric operations; 241 (19%) required admission to the surgical critical care service. We retrospectively reviewed medical records for gender, body mass index (BMI), age, whether the operation was initial or revisional, and whether critical care admission was elective or emergent. 3 complication clusters (thromboembolic, pulmonary, and anastomotic) were identified using discharge ICD-9 codes. The costs and length of stay of these subpopulations was calculated. RESULTS: Patients were on average 46+/-10 years old, with BMI 59+/-13. Critical care admission was emergent in 52.7% (n=127) of cases. Revisional cases did not differ from the initial cases in BMI (56.4 vs 59.2, P=0.42) and they were no more likely to require emergent critical care admission than initial cases (P=0.16). Revisional cases were hospitalized longer (27.2+/-25.6 vs 12.5+/-18.7 days, P=0.003); had higher total hospital costs (US$ 60,631+/-78,337 vs 27,697+/-52,351, P=0.025); and were more likely to die from their complications (revisional surgery mortality 6.5% vs 1.9% for initial surgery [P=0.002]). CONCLUSIONS: An increasing number of surgical revisions will likely accompany the recent increase in popularity of bariatric surgery. In our experience, these patients require significant critical care services, and have longer, complicated, and more costly hospitalizations.

Anastomosis, Surgical↗
PubMed2003

Utstein style analysis of rural out-of-hospital cardiac arrest [OOHCA]: total cardiopulmonary resuscitation (CPR) time inversely correlates with hospital discharge rate.

OBJECTIVE: Survival after out-of-hospital cardiac arrest (OOHCA) in an urban environment is directly proportional to speed of defibrillation and effective bystander cardiopulmonary resuscitation (CPR). We hypothesized that the hospital discharge rate from rural OOHCA was affected by the same factors. METHODS: We studied all OOHCAs in 1998 for rural Alachua County, Florida, with one emergency medical system (EMS) transport provider and three hospitals. All EMS identified OOHCA were reviewed retrospectively, as were EMS and hospital records. The 1998 County population was 211403; 1495 deaths from all causes occurred (70.7/10(4) pop). Of 167 OOHCAs (7.9/10(4) pop), 145 were of cardiac etiology; 22 were excluded (13 scene deaths, four traumatic, one intraoperative and three respiratory arrests, one arrest during a hospital-to-hospital transfer) and in eight outcome data were not available in any form. A total of 137/145 (94.5%) OOHCA patients had analyzable data. Data were analyzed using Student's t-test and ANOVA. Alpha was set at 0.05. RESULTS: Of 25 patients (18.2% of OOHCA) with restoration of spontaneous circulation (ROSC), six survived (4.4% of total, 24% of those with ROSC) to discharge from hospital (four to a skilled nursing facility, one each home with and without assistance). Four patients were still alive at >or=1 year post arrest. Asystole as the initial rhythm (P=0.014), and emergency department (ED) CPR time (8 vs. 15.5 min, P=0.042 for survivors vs. non-survivors) were the only factors statistically affecting survival. While bystander CPR was not significantly different between groups, there was a significantly higher proportion of patients surviving in the ED who had ROSC, and a higher proportion who had ROSC after bystander CPR. Time to defibrillation in nonsurvivors, while not statistically different between city and county patient groups, was clinically different. Statistical significance would likely have been achieved with a larger study population. CONCLUSION: Our data suggest improvement in response time and bystander CPR might further improve survival in a rural setting.

Cardiopulmonary Resuscitation↗
PubMed2003

Respiratory complications in patients with traumatic cervical spine injuries: case report and review of the literature.

Spinal cord injuries continue to be a devastating medical problem. By impairing voluntary and involuntary nervous system function, virtually every body system function is affected. However, pulmonary function alteration and respiratory complications continue to be the major causes of morbidity and mortality in patients with spinal cord injuries. The current understanding of respiratory problems faced by patients with loss of innervation from cervical spinal cord injuries are reviewed.

Critical Care↗
PubMed2003

Burn injuries.

PURPOSE OF REVIEW: To summarize new advances and research findings that relate to the treatment of burn victims. RECENT FINDINGS: Recent advances in burn resuscitation and critical care reflect a better understanding of the acute phase pathophysiology of severe burns. Aggressive management of the unstable burn airway is always the most important clinical priority. Emphasis has been placed on the early identification of inhalation injury and its impact on fluid resuscitation, as well as on a protective lung strategy to reduce the development of pulmonary edema, acute lung injury and pneumonia, and to reduce the risk of barotrauma. New blood markers, such as serum cholinesterase and inflammatory cytokines, have been introduced to assist in the prognosis of morbidity and mortality, beyond the traditional vital signs. At this time, however, these are available only for research purposes. Finally, early burn wound excision and coverage with new biodegradable materials results in less pain and more rapid healing for the patient. SUMMARY: The combination of innovative approaches and a dedicated burn team is expected to continue to improve survival in the next few years even in the most severe cases.

Journal Article↗
PubMed2002

A better landmark for positioning a central venous catheter.

BACKGROUND: Improper positioning of central venous catheters (CVCs) can lead to erosion through the superior vena cava (SVC) or right atrium (RA) and pericardial tamponade. It is widely recommended that the tip of CVCs be placed above the heart or the pericardial reflection. The purpose of this study was to identify an easily recognized landmark to allow identification of the proximal extent of the pericardial reflection on a routine chest radiograph (CXR). METHODS: We analyzed the computerized tomograms of the chest from 97 adults to evaluate the relationship between the pericardial reflection, SVC, carina, and right mainstem bronchus. Correlations between demographic data and length of SVC or pericardial reflection were sought. RESULTS: The mean length of the SVC was 6.5 cm. The pericardial reflection covered an average of 3.6 cm of the distal SVC. The carina was a mean of 1.3 cm below the mid-point of the SVC and 0.7 cm below the pericardial reflection. There was no significant correlation between SVC or pericardial length and either age, height, or weight. CONCLUSIONS: The distal half of the SVC lies within the pericardial reflection, and the upper limit of the pericardial reflection is slightly above the level of the carina. These landmarks are useful for determining proper position of the tip of a CVC on CXR.

Adult↗
PubMed2002

Alternative ventilation strategies in cardiopulmonary resuscitation.

The introduction of the 2000 Guidelines for Cardiopulmonary Resuscitation emphasizes a new, evidence-based approach to the science of ventilation during cardiopulmonary resuscitation (CPR). New laboratory and clinical science underemphasizes the role of ventilation immediately after a dysrhythmic cardiac arrest (arrest primarily resulting from a cardiovascular event, such as ventricular defibrillation or asystole). However, the classic airway patency, breathing, and circulation (ABC) CPR sequence remains a fundamental factor for the immediate survival and neurologic outcome of patients after asphyxial cardiac arrest (cardiac arrest primarily resulting from respiratory arrest). The hidden danger of ventilation of the unprotected airway during cardiac arrest either by mouth-to-mouth or by mask can be minimized by applying ventilation techniques that decrease stomach gas insufflation. This goal can be achieved by decreasing peak inspiratory flow rate, increasing inspiratory time, and decreasing tidal volume to approximately 5 to 7 mL/kg, if oxygen is available. Laboratory and clinical evidence recently supported the important role of alternative airway devices to mask ventilation and endotracheal intubation in the chain of survival. In particular, the laryngeal mask airway and esophageal Combitube proved to be effective alternatives in providing oxygenation and ventilation to the patient in cardiac arrest in the prehospital arena in North America. Prompt recognition of supraglottic obstruction of the airway is fundamental for the management of patients in cardiac arrest when ventilation and oxygenation cannot be provided by conventional methods. "Minimally invasive" cricothyroidotomy devices are now available for the professional health care provider who is not proficient or comfortable with performing an emergency surgical tracheotomy or cricothyroidotomy. Finally, a recent device that affects the relative influence of positive pressure ventilation on the hemodynamics during cardiac arrest has been introduced, the inspiratory impedance threshold valve, with the goal of maximizing coronary and cerebral perfusion while performing CPR. Although the role of this alternative ventilatory methodology in CPR is rapidly being established, we cannot overemphasize the need for proper training to minimize complications and maximize the efficacy of these new devices.

Cardiopulmonary Resuscitation↗