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Biomedical subjects

Fang Gao

Publications and source records attributed to Fang Gao.

11 recordsLinked to original sources

Do different mattresses affect the quality of cardiopulmonary resuscitation?

OBJECTIVE: To determine the effect of different mattresses on cardiopulmonary resuscitation performance and establish whether emergency deflation of an inflatable mattress improves the quality of resuscitation. DESIGN AND SETTING: Randomised controlled cross-over trial performed in a general ICU PARTICIPANTS: Critical care staff from a general ICU. INTERVENTIONS: Cardiopulmonary resuscitation on a manikin on the floor or on a bed with a standard foam mattress and inflated and deflated pressure redistributing mattresses. Maximal compression force was measured at different bed heights. MEASUREMENTS AND RESULTS: Compression depth, duty cycle and rate and percentage correct expired air ventilation were recorded on a manikin. Compression depth was significantly lower on the foam (35.2 mm), inflated (37.2 mm) and deflated mattress (39.1 mm) than the floor (44.2 mm). There were no clinically important differences in duty cycle or compression rate. The quality of ventilation was poor on all surfaces. Maximal compression force declined as bed height increased. CONCLUSIONS: Resuscitation performance is adversely affected when performed on a bed (irrespective of mattress type) compared to the floor. There were no differences between the inflated and deflated mattresses, although the deflation process did not adversely affect performance. This study does not support the routine deflation of an inflated mattress during resuscitation and questions the potential benefits from using a backboard. The finding that bed height affects maximal compression forces, challenges the recommendation that cardiopulmonary resuscitation be performed with the bed at middle-thigh level and requires further investigation.

Beds↗

Discrepancies between clinical and postmortem diagnoses in critically ill patients: an observational study.

INTRODUCTION: The autopsy has long been regarded as an important tool for confirming the clinical cause of death, education and quality assurance. Concerns surrounding informed consent and the retention of organs have heightened clinicians' anxieties in requesting permission to perform an autopsy. The present study was conducted to determine whether the autopsy still has a role to play in extending knowledge about the cause of death in a group of patients who died while receiving intensive care. METHOD: We retrospectively investigated trends in postmortem examination rates and discrepancies between premortem clinical and postmortem diagnoses in a population of critically ill patients admitted to a 13 bed, general medical/surgical intensive care unit between January 1998 and June 2001. Agreement between diagnoses before death and postmortem findings were compared using the Goldman system. RESULTS: Out of total 636 deaths, 49 (7.7%) underwent postmortem examinations. Of these, 38 (78%) cases were available for review. We found that postmortem findings were in complete agreement with predeath diagnoses in fewer than half of the cases (n = 17, 45%). Major missed diagnoses were present in 15 cases (39%). Myocardial infarction, carcinoma and pulmonary embolism represented the most frequently missed diagnoses. CONCLUSION: Postmortem examinations remain a useful tool in confirming diagnostic accuracy and should be considered in all patients who die in the intensive care unit. Recognition of the diagnoses missed before death may improve outcome or avoid unnecessary prolongation of life where terminal disease is present.

APACHE↗

Do changes in pulse oximeter oxygen saturation predict equivalent changes in arterial oxygen saturation?

INTRODUCTION: This study investigates the relation between changes in pulse oximeter oxygen saturation (SpO2) and changes in arterial oxygen saturation (SaO2) in the critically ill, and the effects of acidosis and anaemia on precision of using pulse oximetry to predict SaO2. PATIENTS AND METHODS: Forty-one consecutive patients were recruited from a nine-bed general intensive care unit into a 2-month study. Patients with significant jaundice (bilirubin >40 micromol/l) or inadequate pulse oximetry tracing were excluded. RESULTS: A total of 1085 paired readings demonstrated only moderate correlation (r= 0.606; P < 0.01) between changes in SpO2 and those in SaO2, and the pulse oximeter tended to overestimate actual changes in SaO2. Anaemia increased the degree of positive bias whereas acidosis reduced it. However, the magnitude of these changes was small. CONCLUSION: Changes in SpO2 do not reliably predict equivalent changes in SaO2 in the critically ill. Neither anaemia nor acidosis alters the relation between SpO2 and SaO2 to any clinically important extent.

Acidosis↗

[Nonlinear dynamic analysis of heart rate variability in patients with diabetic autonomic neuropathy].

OBJECTIVE: To explore earlier detection methods for diabetic autonomic neuropathy (DAN) by heart rate variability (HRV) analysis. METHODS: Thirty-four diabetic patients (including 22 with explicit clinical DAN symptoms) were randomly selected for this study from the in-patient department of endocrinology. On the basis of Virtual Instrumental WorkBench- LabVIEW and using several nonlinear dynamic analysis measures, including Allan factor, lyapunov exponent, approximate entropy, fractal dimension, complexity, wavelet-transform standard deviation and nonlinear energy operator, the analysis of the HRV in these diabetic patients was performed in comparison with normal subjects. RESULTS: The nonlinear indices of both DAN patients and patients without obvious DAN were significantly different from those of the normal subjects, especially in terms of Lyapunov exponent, approximate entropy, and nonlinear energy operator. CONCLUSION: Nonlinear dynamic methods of HRV analysis can provide assistance in assessing the status and impairment of the autonomic system, and can be used to efficiently detect diabetic neuropathy in early stages.

Autonomic Nervous System Diseases↗

[Preliminary report on primary drilling procedure at the time of hydroxyapatite orbital implant].

OBJECTIVE: To evaluate the clinical effect of the drilling and inserting a motility peg at the time of hydroxyapatite orbital implant. METHODS: After drilling and insertion of a titanium motility peg, a hydroxyapatite orbital implant was inserted in 31 consecutive patients. Of the 31 patients, 23 had been referred for primary enucleation and 8 for secondary implant surgery. The titanium-threaded sleeve was driven into the hydroxyapatite after which the titanium flat-headed peg was inserted into the sleeve before orbital implantation. The flat-headed peg was replaced with a titanium motility/support peg 3 to 7 months later. RESULTS: Follow-up ranged from 3.0 to 11.0 months (mean, 6.9 months). All patients were successfully fit with prostheses. Prosthetic motility was acceptable in each patient. 12 of 31 titanium flat-headed pegs became spontaneously and partially exposed within 3 to 7 months. There were no cases of secondary infection, implant exposure or extrusion of the motility peg. CONCLUSION: The hydroxyapatite orbital implant primary drilling procedure gives good cosmetic results with good motility of the artificial eye. It does not result in increased complications, and is an effective and efficient surgical option.

Adolescent↗

Photochemistry of racemic and resolved 2-iodooctane. Effect of solvent polarity and viscosity on the chemistry.

The photochemistry of racemic and resolved 2-iodooctane was examined in cyclopentane, methanol, and 2-methyl-2-propanol, media with differing polarities and viscosities. The photochemistry of racemic 2-iodooctane was also examined in the gas phase. The photochemistry of 2-deuterio- and 1,1,1-trideuterio-2-iodooctane in cyclopentane and methanol was also studied. The photoreactions in cyclopentane, 2-methyl-2-propanol, and the gas phase occurred exclusively through homolytic reactions, while in methanol, they occurred predominantly (>53%) through heterolytic reactions. By comparing the disappearance of the optically active substrate with its loss of optical activity, F, the fraction of the initially formed radical pair (RP) or ion pair (IP) resulting in product was determined for the three solvents. Because F contains contributions of both escape of the partners in the RP or IP into the bulk of the solvent and reaction within the RP or IP to yield products other than the substrate, there was no correlation between F and solvent viscosity. The F values will be valuable in assessing the photochemistry of 2-iodooctane in the same media with circularly polarized light.

Journal Article↗

[Association of insertion/deletion polymorphism in angiotensin-converting enzyme gene with hypertensive type 2 diabetes mellitus].

OBJECTIVE: To elucidate the interaction between the insertion/deletion (I/D) polymorphism in angiotensin converting enzyme (ACE) gene and hypertensive type 2 diabetes mellitus. METHOD: I/D polymorphism in ACE gene was determined with PCR technique in 82 hypertensive and 117 non-hypertensive patients with type 2 diabetes. RESULTS: The comparison between the 2 groups revealed a significant difference in DD/DI/II genotype distribution and D/I allele carrying (chi(2)=6.41, P<0.05), indicating an association of DD genotype and D allele carrying with the occurrence of hypertensive type 2 diabetes. Diabetic patients with I/D polymorphism in ACE gene complicated by hypertension had 1.32 times higher risk than non-hypertensive type 2 diabetic patients, and the course of hypertensive type 2 diabetes was significantly lengthened. No significant difference of I/D polymorphism in ACE gene was identified between normotensive diabetic patients and diabetic patients with elevated diastolic blood pressure, but the close correlation was found between normotensive diabetic patients and diabetic patients with elevated systolic pressure. CONCLUSIONS: I/D polymorphism in ACE gene contributed to development of hypertensive type 2 diabetes. D allele might be an important risk factor for hypertensive type 2 diabetes, and elevation of diastolic blood pressure plays an important role in the occurrence of hypertensive type 2 diabetes.

Adult↗

[Serum uric acid in type 2 diabetic patients complicated by stroke].

OBJECTIVE: To investigate the association of hyperuricemia with the incidence of stroke in type 2 diabetic patients. METHODS: Sixty type 2 diabetic patients with stroke, 75 patients with simple stoke and 67 simple type 2 diabetic patients were randomly selected from the hospitalized patients. The serum levels of uric acid (UA), total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol(LDL), very-low-density lipoproteincholesterol (VLDL) and high-density lipoprotein- cholesterol (HDL) of all the patients were determined and comparison between the groups performed. RESULTS: Male type 2 diabetic patients with stroke had significantly higher mean levels of serum uric acid than simple diabetic patients, but such patients of both genders all had lower HDL levels. CONCLUSION: The decreased serum HDL level poses as an important risk factor for stroke in all type 2 diabetic patients, among whom the male patients in particular have hyperuricemia as another important risk factor for stroke.

Cholesterol, HDL↗

[Decrease in tetanic tension in 4-week tail-suspended rat soleus and analysis of its underlying mechanisms].

Objective. To observe the dynamic changes in tetanic tension in 4-week tail-suspended rat soleus (SOL) and extensor digitorum longus muscle (EDL) and to elucidate its underlying mechanisms. Method. After 4 weeks of tail suspension SOL and EDL of the rats were isolated and perfused. Their isometric twitch and tetanic tensions were recorded. Result. Atrophy occurred in the SOL, but not in the EDL. The maximum twitch tension (Pt) decreased significantly and was more dependent on stimulation voltage in SOL of tail-suspended rat. Time to maximum twitch tension (TPT) and time from maximum twitch tension to half relaxation (TR50) were reduced in the SOL. Pt also decreased in the EDL, but TPT and TR50 did not change in the EDL. The maximum tetanic tension reduced in SOL and EDL of tail-suspended rats. The decline rate of tetanic tension in SOL was faster than the control. The profile of tetanic contraction curve in atrophic SOL approached that in EDL. Conclusion. The above results suggested that the underlying mechanisms of reduced maximum twitch and tetanic tension in 4-week tail-suspended rat SOL may involve the reduction in number of cross-bridge per cross-section area or force produced per cross-bridge. The rapid decline rate in atrophic SOL may be related to the shift in myosin heavy chain and troponin I isoforms or to decrease in excitability.

Animals↗

[Expression of myosin heavy chain IIx mRNA as a molecular marker of disuse of soleus muscle in rats].

Objective. To make an Achilles tenotomy rat model to observe the change in soleus weight and expression of myosin heavy chain (MHC) isoform mRNA, and to find some clues for elucidating the mechanisms of soleus disuse. Method. Thirty male Sprague-Dawley [correction of Sprangue] rats were divided into 6 groups. On the lst, 3rd, 7th, 14th, 21st and 28th days after Achilles tenotomy, wet weight of soleus (SOL), plantaris (PL), gastrocnemius mediales (MG), and gastrocnemius lateral (LG) muscles were measured. Expression of MHC IIx mRNA was observed by means of reverse transcriptase-polymerase chain reaction (RT-PCR). Result. Wet weight of SOL, MG, LG, and PL decreased significantly on the 3rd day after the tenotomy. The wet weight of these muscles reduced to the minimum on the 7th or 14th days after the tenotomy, and then recovered slightly on the 21st day after the tenotomy. There was only the expression of MHC I and MHC IIa mRNA in normal soleus muscle, but no MHC IIx or MHC IIb mRNA. The expression of MHC IIx mRNA occurred in SOL on the 3rd day after tenotomy and still expressed on the 28th day after tenotomy. There was no expression of MHC IIb mRNA in SOL after Achilles tenotomy. Conclusion. The appearance of atrophy of rat soleus induced by Achilles tenotomy is similar in time and extent with that induced by tail-suspension. The expression of MHC IIx mRNA is shown in rat soleus muscles in Achilles tenotomy and tail-suspension models. The study suggests that expression of MHC IIx mRNA may be used as a molecular marker of soleus muscle disuse in rats.

Achilles Tendon↗