Are your thoughts of facial pressure transparent?

Facial burns present many psychological and rehabilitation challenges. Many of our patients with facial burns who are children and adolescents have expressed that they prefer to wear the transparent face mask instead of the Jobst hood (Beiersdorf Jobst Inc, Charlotte, NC) with an underlying silicone face pad. However, questions have been raised about the consistency and amount of pressure provided by the transparent face mask. Pressure was measured under the customized transparent face mask, under the customized silicone face pad with a Jobst hood, and under the customized Jobst hood to ascertain pressure differences for a single patient. No significant difference in pressure was observed between the transparent facemask and the silicone face pad with a Jobst hood. We recommend the use of the transparent face mask on patients with severe facial burns who may require pressure to improve the appearance of their scars.     

Supersonic shear wave elastography of in vivo pig kidney: influence of blood pressure, urinary pressure and tissue anisotropy

The in vivo influence of renal anisotropy and of urinary and vascular pressure on elasticity values using ultrasonic supersonic shear wave elastography was studied in pigs. Experiments were conducted in agreement with the European Commission guidelines and directives of the French Research Ministry. Six kidneys in three pigs were studied in vivo. Elasticity of renal cortex and medulla was quantified through the shear modulus (μ) by using the supersonic shear imaging technique with an 8 MHz linear ultrasound probe. All measurements were done peroperatively both in the axis and perpendicular to the main axis of pyramids, in normal condition, after progressive increase of urinary pressure, and after renal artery and renal vein ligation. In normal conditions, cortical (C) and medullary (M) elasticity values were always higher when acquisitions were realized with the ultrasound main axis perpendicular to main pyramid axis (C_//: 7.7 ± 2.3 kPa; M_//: 8.7 ± 2.5 kPa) than parallel (C_⊥: 6.9 ± 1.4 kPa; M_⊥: 6.6 ± 2.3 kPa), demonstrating an effect of renal anisotropy. In renal cortex, two bands were separated, inner cortex showing higher elasticity values (IC_⊥: 8.1 ± 1.9 kPa) than outer cortex (OC_⊥: 6.9 ± 1.4 kPa). Renal artery and renal vein ligation induced a decrease and an increase of elasticity respectively. Parenchymal elasticity increased linearly with elevation of urinary pressure. Intrarenal elasticity values vary with tissue anisotropy and, with vascular and urinary pressure levels. These parameters have to be taken into account for interpretation of tissue changes. Separation of outer and inner cortex could be attributable to perfusion differences.     

Respiratory variation of intra-abdominal pressure: indirect indicator of abdominal compliance?

OBJECTIVE: To assess if the observed respiratory cycle-related variation in intra-abdominal pressure is reliably quantifiable and a possible indirect indicator of abdominal compliance. Secondary issues were to assess the roles played by respiratory parameters in determining this oscillation and by patients' position in increasing their intra-abdominal pressure. DESIGN AND SETTING: Prospective observational study in a 26-bed medical-surgical intensive care unit. PATIENTS: Sixteen consecutive patients admitted to intensive care for at least 24 h, requiring mechanical ventilation and intra-abdominal pressure monitoring. MEASUREMENTS AND RESULTS: Intra-abdominal pressure was measured with a modified Kron technique; its waveform was recorded and inspiratory and expiratory values were measured during five consecutive respiratory cycles for 5 days, both in the supine and the 30 degrees head-up position. Inspiratory values were significantly higher than expiratory values (p = 0.001) and a correlation was found between their difference and intra-abdominal pressure basal values (p = 0.025). A positive linear relationship was shown between intra-abdominal pressure and the amplitude of its oscillation (r = 0.4), particularly in the subgroup of patients with intra-abdominal hypertension (r = 0.9). Intra-abdominal pressure was lower in patients supine than in the 30 degrees head-up position (p = 0.001). CONCLUSIONS: Respiratory cycle-related variations in intra-abdominal pressure were specifically investigated, quantified and shown as linearly increasing with end-expiratory intra-abdominal pressure; this phenomenon could be explained by patients' abdominal compliance status. Supine posture should be an important consideration in specific patients affected by intra-abdominal hypertension.     

Influence of changing bad living habits on blood pressure control of hypertension patients

Living habits with smoking,obesity and rest is high risk factor of hypertension.Every hypertension patient including those receiving drug therapy should change living habit.When living habit ameliorate,decompression function can be observed and risk factors of hypertension decrease.OBJECTIVE:To investigate Influence of changing bad living habits on blood pressure control of hypertension patients.UNIT:Department of Cardiology Internal Medicine of Second People‘s Hospital of Wenzhou.SUBJECTS:173 hypertension cases from September 1999 to June 2001,who accord with WHO diagnosis criteria issued 1999,including 129 males and 44 females,age 32-93,average age 67.INTERVENTION:Except for routine drug therapy,all the patients received health education,which focus on changing bad living habits,including:(1)Mental instruction:Some studies showed that modd of patients with hypertension was unstable,interpersonal relationship was sensitive or combined with anxiety,depression and paranoid.To this kind of patients,we adopted mental dredging,relaxing therapy,listening music,setting up their insterestings,et al,to change their mood,encourage patients to actively take part in all kinds of beneficial activities,keep calm,avoid exiting of mood,train self-control ability and keep good mental state.(2)Guide diet:restrict salt,high cholesterol,high fat diet and supply proper potassium,calcium and magnesium.Everyday intake of sodium should be less than 6g,fried foods and visceral of animal should be reduced,fruits containing more potassium such as orange,banana were eaten to control hypertension.Diets should contain vitamins,superior protein,calcium,Mg such as milk,fishes,musroom,vegetables,fruits.vitamins could promote metabolism of lipoids,especially that vitamin C could decrease catelone level.Ca,Mg also did good to decreasing of blood pressure.(3) Control weight:45 cases combined with obesity control weight.(4)Stop smoking and drinking.(5)Construct good living habit,take media and low strength exercise such as walk,jog,riding bicycle and gymnastics.Every patient take exercises 3-5 times every week with about half an hour for each time.RESULT:In these 173 cases,157 cases master self-care knowledge and health living habit and BP was under control.BP of 59 cases were fluctuating,after psychic nurse and removal of bad habits,BP was well controlled.CONCLUSION:Changing bad living habits play important function on blood pressure control of hypertension patients.     

Do pressure relief cushions really relieve pressure?

In a laboratory setting, interface pressures of 29 cushions and a sheepskin were measured on 20 healthy volunteers. Each participant was seated in an upright posture with their back against the back of the chair, hands resting on the lap, knees bent at an angle of 90 degrees, and feet resting on the floor. Only 13 cushions had any pressure-reducing effect. Gel cushions and sheepskins appear to have no pressure-reducing effect. The category of foam includes both cushions that reduce interface pressure very well and cushions that increase interface pressure. The lowest interface pressures were measured on air cushions and on some foam cushions.     

Is proximal airway pressure a good reflection of peripheral airspace pressure in infants and children models under HFJV?

This expriimental study was carried out to determine if an alveolar positive end-expiratory pressure (PEEP) could occur during high frequency jet ventilation (HFJV) in infants, and if tracheal pressure is a good estimation of alveolar pressure.We used physical models simulating a 1.5 kg premature (P), a 3 kg newborn (N) and a 6 kg child (C) with normal compliance and normal resistance. Moreover, in the N model, we used two different resistances and lung compliance heterogeneity was studied in the P model. Pressure was measured simultaneously in the tube simulating trachea (Paw) and in the bottle simulating the lung (Palv). HFJV was performed either via an endotracheal tube (ETT) or via a long catheter as in laryngoscopy. The ratio of injection time upon cycle duration (Ti/Ttot) was 20% or 30%, jet frequency was altered from 150 to 300 min^–1 and the driving pressure was set as in clinical practice (0.5 and 0.6 bar).PEEP occurred mainly in N (1.1 to 3.2 cm H2O) and C models (0 to 3.5 cm H2O). It was inversely related to expiratory time (Te). The end-expiratory pressure drop between Palv and Paw (EEP) was higher in N and increased from 0.5 to 2 cm H2O with the shortening of Te and with airway resistances, i.e. the presence of ETT. In the heterogeneous model, PEEP and EEP were greater in the higher compliance alveolus.This study shows that the end-expiratory Palv is underestimated by end-expiratory Paw. This is particularly important in the presence of an heterogeneity of distribution in lung compliance. In this case the airway PEEP overestimates the PEEP in the lower compliance alveolus and underestimates the PEEP in the higher compliance alveolus.     

Relationship between complication s of cardio-cerebral vessels and control of blood pressure in senile hypertension

Hypertensionisaseriousdiseasethreateningthehealthoftheagedandoftenleadstodisabilityandevendeathduetoseriousdiseasesofheart,brainandkidney.From1999,213casesofsenilehypertensionweretreatedinourdepartment.1Subjectsandmethods1.1SubjectsPatientswithsenilehypertensiontreatedfrom1999to2002wereselectedanddiagnosiswasaccordedtostandardsfor-mulatedbyworldhealthorganizationandinternationalsocietyofheartdisease(WHO/ISH).213caseswereinvestigatedincluding162malesand51femalesaged60～87(mean:67.3)yearsold.…     

Detection of ‘best’ positive end-expiratory pressure derived from electrical impedance tomography parameters during a decremental positive end-expiratory pressure trial

Introduction

This study compares different parameters derived from electrical impedance tomography (EIT) data to define ‘best’ positive end-expiratory pressure (PEEP) during a decremental PEEP trial in mechanically-ventilated patients. ‘Best’ PEEP is regarded as minimal lung collapse and overdistention in order to prevent ventilator-induced lung injury.

Methods

A decremental PEEP trial (from 15 to 0 cm H₂O PEEP in 4 steps) was performed in 12 post-cardiac surgery patients on the ICU. At each PEEP step, EIT measurements were performed and from this data the following were calculated: tidal impedance variation (TIV), regional compliance, ventilation surface area (VSA), center of ventilation (COV), regional ventilation delay (RVD index), global inhomogeneity (GI index), and intratidal gas distribution. From the latter parameter we developed the ITV index as a new homogeneity parameter. The EIT parameters were compared with dynamic compliance and the PaO₂/FiO₂ ratio.

Results

Dynamic compliance and the PaO₂/FiO₂ ratio had the highest value at 10 and 15 cm H₂O PEEP, respectively. TIV, regional compliance and VSA had a maximum value at 5 cm H₂O PEEP for the non-dependent lung region and a maximal value at 15 cm H₂O PEEP for the dependent lung region. GI index showed the lowest value at 10 cm H₂O PEEP, whereas for COV and the RVD index this was at 15 cm H₂O PEEP. The intratidal gas distribution showed an equal contribution of both lung regions at a specific PEEP level in each patient.

Conclusion

In post-cardiac surgery patients, the ITV index was comparable with dynamic compliance to indicate ‘best’ PEEP. The ITV index can visualize the PEEP level at which ventilation of the non-dependent region is diminished, indicating overdistention. Additional studies should test whether application of this specific PEEP level leads to better outcome and also confirm these results in patients with acute respiratory distress syndrome.     

Transient stop-flow arm arterial–venous equilibrium pressure measurement: determination of precision of the technique

Transient stop-flow arm arterial–venous equilibrium pressure (Pmsf-arm) is a validated technique for measuring the mean systemic filling pressure (Pmsf). Pmsf is a functional measure of the effective intravascular volume status. This study aims to assess the precision of the Pmsf-arm measurement. Pmsf-arm was measured by inflating a pneumatic tourniquet around the upper arm 50 mmHg above systolic pressure for 60 s, four times consecutively, with an interval of 5 min. Arterial (Pa) and venous pressure (Pv) were recorded every 10 s. Pa–Pv difference was calculated to determine the stop-flow time. The coefficient error (CE) was determined and used to derive the least significant change (LSC) in Pmsf-arm that this technique could reliably detect. The rANOVA test was used to compare repeated measurements of the four determinations of Pmsf-arm. 80 measurements of Pmsf-arm were studied in 20 patients. Pa and Pv equalised after 60 s of inflation (Pa–Pv difference 0 ± 0.01 mmHg). There were no significant differences of Pmsf-arm values among determinations. For a single measurement, the CE was 5 % (±2 %) and the LSC was 14 % (±5 %). Averaging two, three and four measurements the CE improves to 4 % (±1 %), 3 % (±1 %) and 3 % (±1 %) respectively, and the LSC was reduced to 10 % (±4 %), 8 % (±3 %) and 7 % (±3 %) respectively. One measurement of Pmsf-arm can reliably detect changes on Pmsf-arm of 14 %. The precision of Pmsf-arm technique improves when averaging two or three measurements.     

The etiology of pressure ulcers: skin deep or muscle bound?

Pressure ulcers are areas of soft tissue breakdown that result from sustained mechanical loading of the skin and underlying tissues; they can affect the quality of life of many individuals. Despite considerable efforts to prevent pressure ulcers, data on prevalence are unacceptably high. This can at least partly be attributed to limited knowledge of the etiology of the clinical condition and the fact that identification and prevention of pressure ulcers mainly focus on skin tissue, even though the underlying muscle tissue may be more susceptible to mechanical loading. The present article proposes a new, hierarchical research approach to obtain improved insights into the basic pathways whereby mechanical loading leads to soft tissue breakdown. This approach investigates the relationships between (1) global mechanical loading at skin level, (2) the resulting local internal mechanical conditions within the soft tissue layers extending from skin to muscle tissue, and (3) the pathophysiologic response to loading. The latter response should be assessed from the various functional tissue units involved in soft-tissue breakdown-the cells, the interstitial space, and blood and lymph vessels. We predict that the proposed strategy will provide new fundamental knowledge about the etiology of pressure ulcers that can serve as a sound basis for effective clinical identification and prevention.     

Maintenance of tracheal tube cuff pressure: where are the limits?

Continuous control of tracheal tube cuff inflation using a pneumatic device resulted in severe tracheal wall damage in ventilated piglets. This damage was similar in piglets managed with manual control of cuff inflation. The periodic hyperinflation of the tube cuff used in both groups of this study may explain these results. This manoeuvre should be avoided in clinical practice.     

Relationship between complications of cardio—cerebral vessels and control of blood pressure in senile hypertension

Hypertension is a serious disease threatening the health of the aged and often leads to disability and even death due to serious diseases of heart,brain and kidney,From 1999,213 cases of senile hypertension were treated in our department.     

Does the evaluation of the pressure ulcer risk increase better prevention?

The aim of the study was to indagate if pressure sore risk group patients in a 500 beds' hospital received more preventive care of a no risk control sample. Data have been collected on all patients (minimum stay of three days) from admission to discharge using an assessment dedicated tool. Results of a modified Norton Scale show that a 20% of pressure sores' risk patients receive more preventive care. A positive correlation was demonstrated particularly with: patient's position, bed side at 30 degrees inclination, pillows use, preventive local medications. However, in both groups, the general preventive intervention was definite as low. While an encrease of pressure sores (12%) has been demonstrated in the risk group, no alteration has been reported in the control group.