Nutrition-related status and granulation tissue colour of pressure ulcers evaluated by digital image analysis in older patients.

OBJECTIVE: Granulation tissue colour may be an indicator for nutritional assessment in pressure ulcer (PU) care. This study evaluated the relationship between nutritional status, anaemia and diabetes, and granulation tissue colour of PUs by colour analysis of digital photographs in the clinical setting. METHOD: The cross-sectional study included 42 older patients with 51 full-thickness PUs from 10 institutions. Patient demographics, wound status, nutritional status and dietary intakes were obtained from medical charts. From a wound image, the granulation red index was processed by computer software and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) was calculated. RESULTS: Haemoglobin levels were positively associated with %GRI80 levels (p=0.007) in the crude model, but not in the adjusted model (p=0.260). The interaction term between diabetes and protein intake was significantly associated with %GRI80 levels in the adjusted models (p=0.010). At protein intakes of 0.95 g/kg or higher, diabetic wounds exhibited lower %GRI80 levels than non-diabetic wounds (p=0.002). At protein intakes of less than 0.95 g/kg, %GRI80 levels did not differ between diabetic and non-diabetic patients (p=0.247). Protein intakes of 0.95 g/kg or higher were associated with higher %GRI80 levels in non-diabetic patients (p=0.015), but not in diabetic patients (p=0.127). CONCLUSION: Granulation tissue colour, evaluated by the objective and quantitative analysis of digital photography, is related to haemoglobin level, diabetes and dietary intakes in clinical settings.

Quantitative estimation of exudate volume for full-thickness pressure ulcers: the ESTimation method.

OBJECTIVE: To develop an equation for the estimation of exudate volume in millilitres, for full-thickness pressure ulcers, according to wound characteristics. METHOD: In a cross-sectional study, 41 patients aged >60 years with 58 full-thickness pressure ulcers were evaluated. Exudate was collected by covering each wound with a transparent occlusive dressing and the accumulated volume was measured to estimate volume per day. The overall severity of each wound was evaluated by the DESIGN-R tool; a model was then developed to estimate the volume of exudate based on these experimental values. Linear regression analyses were performed to evaluate the precision and accuracy of the model. RESULTS: The model, including exudate score, size score, and total score, showed a higher adjusted coefficient of determination (R²=0.66) than the model with only a traditional exudate score (R²=0.57). After adjustment for age, inclusion of interaction terms, and modification of bias, a model with continuous parameters was finally developed: exudate volume per day (ml/day) = exp([0.86×exudate score]+ [0.21×size score]+[0.12×total score]-[0.013×size score×total score]-[0.04×age]-3.60). Furthermore, a categorical model was developed for clinical simplicity of use. The adjusted R2 was increased to 0.73 for the continuous model and to 0.77 for the categorical model. There were no apparent biases (p>0.05) and no correlations between residuals and measured value (p>0.05) in these models. CONCLUSION: The equation, including the exudate score, size score and total score of DESIGN-R, as well as age, is called the ESTimation method. It will be useful for clinicians to predict the absolute volume of exudate and to select appropriate dressings for full-thickness pressure ulcers. DECLARATION OF INTEREST: The authors have nothing to declare.

Predicting delayed pressure ulcer healing using thermography: a prospective cohort study.

OBJECTIVE: To investigate whether thermography can be used to detect latent inflammation in pressure ulcers and predict pressure ulcer prognosis in a clinical setting. METHOD: For this cohort study, we recruited 35 patients with stage II-IV pressure ulcers on the torso, who underwent thermographic assessment on discovery of their pressure ulcer. The patients were followed up for at least 3 weeks. Thermography was performed immediately after dressing removal. Pressure ulcers were classified into two groups depending on whether or not the wound site temperature was lower or higher than the periwound skin: the low temperature group and the high temperature group respectively. A generalised estimation equation was used to estimate the relative risk of delayed healing of pressure ulcers, comparing wounds with high temperatures and low temperatures. RESULTS: Of the 35 patients, 21 had 'low temperature' wounds and 14 had 'high temperature' wounds at baseline. Two patients in the high temperature group presented with overt infection, and were excluded from further analysis. Twenty-two pressure ulcers were considered to heal 'normally' (that is, the wound area reduced by 30% or more within 3 weeks) and 16 did not heal. The baseline DESIGN score (a measure of gross wound status) did not differ in any subscales between the high and low temperature groups. The relative risk for delayed healing in high temperature cases was 2.25 (95% confidence intervals; 1.13-4.47, p=0.021). Sensitivity was 0.56, specificity was 0.82, positive predictive value was 0.75, and negative predictive value was 0.67. CONCLUSION: Our results indicate that using thermography to classify pressure ulcers according to temperature could be a useful predictor of healing at 3 weeks, even though wound appearances may not differ at the point of thermographical assessment. The higher temperature in the wound site, when compared with periwound skin, may imply the presence of critical colonisation, or other factors which disturb the wound healing.

Can ultrasonographic evaluation of subcutaneous fat predict pressure ulceration?

High-resolution ultrasound may be able to detect pressure ulcers before clinical signs emerge. This retrospective study found that one such early indicator is inflammatory oedema in the subcutaneous fat, which resolves as healing occurs.

Ultrasonographic evaluation of an unusual peri-anal induration: a possible case of deep tissue injury.

High-resolution ultrasound produces good quality echo images of skin and subcutaneous lesions. Here, it was used to characterise an atypical induration, which the authors speculate might have been a deep tissue injury.

Coronary artery bypass with only in situ bilateral internal thoracic arteries and right gastroepiploic artery.

BACKGROUND: With the rapid advance of catheter intervention, the direction taken by surgeons is not only to make conventional CABG less invasive but also to pursue better long-term results by using more arterial conduits. METHODS AND RESULTS: Between July 1989 and April 2000, 239 patients (218 men, 21 women) with a mean age of 59.7 (range 39 to 79) years underwent CABG with exclusive use of both internal thoracic arteries (ITAs) and the right gastroepiploic artery (RGEA). ITA grafts were harvested by using the skeletonization technique. Most patients (96%) had either triple-vessel or left main disease. Fifty percent of the patients were diabetic, and 16 were being treated with insulin. The left ventricular ejection fraction was

Angiotensin II type 2 receptor mediates vascular smooth muscle cell apoptosis in cystic medial degeneration associated with Marfan's syndrome.

BACKGROUND: Cystic medial degeneration (CMD) is a histological abnormality that is common in the aortic diseases associated with Marfan's syndrome (MFS). Although little known about the mechanism underlying CMD, several recent reports have demonstrated that vascular smooth muscle cell (VSMC) apoptosis could play a substantial role in CMD. On the other hand, angiotensin II (Ang II) has been reported to play an important role in the regulation of VSMC growth and apoptosis via the Ang II type 1 receptor (AT1R) and type 2 receptor (AT2R). METHODS AND RESULTS: To elucidate the role of Ang II signaling via the Ang II receptors in CMD, we investigated AT1R and AT2R mRNA expression and tissue concentration of Ang II in MFS aortas (n=10) and control aortas (n=12). Furthermore, we examined the effects of an ACE inhibitor, an AT1R blocker, and an AT2R blocker on serum deprivation-induced VSMC apoptosis by organ culture system. AT1R expression was significantly decreased (P<0.01) and AT2R expression was significantly increased (P<0.001) in MFS aortas compared with control aortas, and tissue Ang II concentration was significantly higher in CMD than in the control condition (P<0.01). Both the ACE inhibitor and AT2R blocker significantly inhibited serum deprivation-induced VSMC apoptosis (P<0.05), although the AT1R blocker did not inhibit apoptosis in cultured aortic media from MFS patients. CONCLUSIONS: Accelerated ACE-dependent Ang II formation and signaling via upregulated AT2R play a pivotal role in VSMC apoptosis in CMD, and the ACE inhibitor could have clinical value in the prevention and treatment of CMD.

Regional work of the human left ventricle calculated by wall stress and the natural logarithm of reciprocal of wall thickness.

Regional left ventricular work is a more precise indicator of function than is simple shortening fraction. Regional work of the ventricle normalized to a unit volume of myocardium (RWM) is given by the following equation: RWM = - intergral of sigma d[ln(1/H)], where sigma is the mean wall stress and ln(1/H) is the natural logarithm of reciprocal of wall thickness. This method has been previously validated in animal experiments and it is now extended to the clinical setting for the first time. In 10 normal subjects and 6 patients with anteroseptal myocardial infarction, ventricular minor axis and wall thickness were measured by echocardiography and recorded simultaneously with high fidelity left ventricular pressure. Then, regional work of the interventricular septum and of the posterior wall of the left ventricle was calculated from the measured pressure and dimension data. In normal subjects, regional work of the septum and posterior wall was 6.1 +/- 1.7 and 7.0 +/- 1.8 mJ/cm3, respectively; the average of the septal and posterior wall regional work multiplied by the left ventricular myocardial volume correlated well (r = 0.93) with the total mechanical work done by the entire left ventricle. In patients with anteroseptal infarction, septal regional work was greatly reduced (0.6 +/- 1.7 mJ/cm3), compared with posterior wall regional work in the same patients (6.1 +/- 1.8 mJ/cm3). This simple method can be applied clinically in assessing the functional state of different regions of the myocardium.

Models of lineage switching in hematopoietic development: a new myeloid-committed eosinophil cell line (YJ) demonstrates trilineage potential.

A new human leukemia cell line with an eosinophilic phenotype, designated YJ, was established from the peripheral blood cells of a patient with chronic myelomonocytic leukemia (CMMoL) with eosinophilia. When cultured in RPMI 1640 medium containing 10% fetal bovine serum, most YJ cells were myeloblastoid with a small number of the cells having eosinophilic granules. Cell surface markers in the YJ cells were positive for CD33 and were negative for CD34, CD16 and CD23. The eosinophilic characteristics of YJ cells were confirmed by histochemical staining with Fast-Green/Neutral-Red and by the expression of mRNAs for eosinophil-associated granule proteins, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), eosinophil peroxidase (EPO), and major basic protein (MBP), and for the Charcot-Leyden crystal (CLC) protein. The YJ cells could be induced towards monocytic differentiation by stimulation with phorbol 12-myristate 13-acetate (PMA). The monocytic characteristics of YJ cells treated with PMA were confirmed by morphological analysis with alpha-naphthyl butyrate esterase staining, by CD14 expression, and by increased expression of Egr-1 mRNA. Furthermore, YJ cells could be differentiated towards the neutrophil lineage by stimulation with all-trans retinoic acid (RA). YJ cells treated in vitro with 2 microM RA differentiated into metamyelocytes and band neutrophils, and increased the number of nitroblue tetrazolium (NBT)-positive cells and increased gp91phox mRNA expression. Thus, the YJ cell line exhibited eosinophilic characteristics, but was able to differentiate to the monocytic or neutrophilic lineages in response to PMA or RA, respectively. The expression of genes for transcription factors involved in myeloid differentiation was evaluated by Northern blot analysis. Increased expression of Egr-1 was observed with macrophage differentiation. In contrast, increased expressions of C/EBPbeta and MZF-1 mRNA occurred with neutrophilic differentiation. The YJ cell line should be useful for elucidating the molecular mechanisms governing lineage switching from the eosinophil to monocytic or neutrophil lineages.

Inhibitory effect of Multiglycosidorum tripterygii on coronary arteriosclerosis after heart transplantation.

BACKGROUND: Graft coronary arteriosclerosis (GCA) is the major limiting factor for long-term survival after heart transplantation. In this study, we investigated the effect of Multiglycosidorum tripterygii (MT) on GCA and platelet-derived growth factor A (PDGF-A) mRNA expression of transplanted hearts. METHODS: Two groups of Lewis rats (n=7/group) underwent heterotopic heart transplantation from Wistar-King donors and were treated with either cyclosporine (CsA;10 mg/kg/day) or MT (30 mg/kg/ day). Histological evaluations of rejection and coronary arteriosclerosis, as well as Northern blot analysis on graft PDGF-A mRNA expression were made 60 days after transplantation. RESULTS: Morphometric results indicated no significant difference in rejection between the CsA- and MT-treated groups. However, the extent of GCA in the MT-treated group was significantly less than that seen in the CsA-treated group (P<0.01). The expression of PDGF-A mRNA of cardiac allograft was also significantly suppressed in the MT-treated group when compared with the CsA-treated group (P<0.01). CONCLUSION: MT is superior to CsA in preventing graft coronary arteriosclerosis, and this efficacy is probably associated with the depressed expression of graft PDGF-A mRNA in the MT-treated group.

Effectiveness of ischemic preconditioning on long-term myocardial preservation.

BACKGROUND: This study was designed to assess whether the protective effect of ischemic preconditioning can be adapted for myocardium undergoing 6 hr of ischemia. METHODS: Eighteen isolated rat hearts were perfused with oxygen-bicarbonated Krebs-Henseleit buffer in the Langendorff mode for 35 min (group A, controls) or perfused in the Langendorff apparatus for 20 min, followed by 5 min of global normothermic ischemia and 10 min of buffer perfusion (group B, preconditioning) or followed by two cycles of 2.5 min of global normothermic ischemia plus 5 min of buffer perfusion (group C, preconditioning). The hearts were then arrested and preserved for 6 hr with Bretschneider's histidine-tryptophan-potassium cardioplegic solution at 4 degrees C, followed by 30 min of reperfusion. Recovery of cardiac function, postischemic enzyme leakage, and intracellular calcium concentration were compared. RESULTS: After 6 hr of ischemia, the hearts that underwent preconditioning in groups B and C showed better recovery of left ventricular developed pressure (P<0.05), a lower end-diastolic pressure level (P<0.05), less leakage of creatine kinase, and a lower intracellular calcium concentration than those in group A. There were no statistical differences in the rate of recovery of coronary flow. CONCLUSIONS: Our study demonstrated that ischemic preconditioning improves myocardial functional recovery after 6 hr of hypothermic preservation in the isolated rat heart. Preconditioning might be useful for preserving the heart against long-term ischemia/reperfusion injury.

Measurement of severity of aortic stenosis experimentally produced in dogs without inserting a catheter into the left ventricle.

When flow passes through an orifice, pressure loss does not occur in the laminar core of the jet distal to the stenosis, but occurs in the region more distal to the stenosis, where the laminar core disappears and turbulence develops. Therefore, if total pressure is measured in the laminar core of the jet some distance downstream of a stenotic aortic valve, it should be equal to total pressure on the left ventricular side of the aortic valve. An experimental study was performed in 5 dogs to test this hypothesis. The results revealed that left ventricular pressure during the ejection period can be determined by measuring the pressure in the laminar core. A preliminary evaluation of the clinical applicability of our method was performed during catheterization in a patient with severe aortic valve stenosis. In this case, the pressure obtained in the jet downstream of the aortic valve was slightly lower than that obtained in the left ventricle.

Aorta-coronary bypass grafting with heparinized vascular grafts in dogs. A preliminary study.

At present, only the autogenous saphenous vein is acceptable in aorta-coronary bypass grafting. We developed a small-caliber vascular graft and evaluated the potential application for aorta-coronary bypass grafting. Canine carotid arteries were cross-linked with polyepoxy compounds, such as polyglycerol polyglycidyl ether, which is a new cross-linking reagent, and then heparinized by our own method. The polyepoxy compound-cross-linked graft can keep the natural vessel compliance and is stronger than the glutaraldehyde-cross-linked graft; thus, it provides excellent suturability and compliance match. Heparin was gradually released from the graft wall, and thrombus formation was completely prevented during the period before development of the endothelial lining. As a pilot study, the grafts, 2 to 3 mm in internal diameter and 5 to 7 cm in length, were evaluated as bilateral carotid replacements in five dogs. All grafts were patent at intervals of 14 to 177 days. Histologic examinations showed excellent antithrombogenic and healing characteristics, although the endothelialization was delayed by heparin, which inhibits cell adhesion and fibrin deposition. The 3 mm internal diameter graft was evaluated as an aorta-coronary bypass grafting model in eight dogs. Flow within grafts to the right coronary artery ranged from 25 to 35 ml/min, and flow in the circumflex or left anterior descending grafts ranged from 75 to 100 ml/min. Cineangiography was performed to confirm graft patency. Three dogs died of viral infection and one was killed. At necropsy, the grafts remained patent without thrombi along the graft length. Four dogs were allowed to survive for long-term evaluation. All grafts were patent at time intervals to 21 to 113 days with 100% patency. These results led us to conclude that our newly developed small-caliber vascular graft shows great promise in application for aorta-coronary bypass grafting.

Conduction disturbance in Behçet's disease. Association with ruptured aneurysm of the sinus of valsalva into the left ventricular cavity.

Cardio-Behcet's disease is not often reported; only one case to our knowledge has described complete atrioventricular (AV) block, without pathologic details. We document, from direct observation during surgery and pathologic examination of associated lesions, a case whose conduction disturbance was possibly caused by direct extension of Behcet's disease itself into the conduction system.

Regional differences in myocardial work of the left ventricle in patients with idiopathic dilated cardiomyopathy: Implications for the surgical technique used for left ventriculoplasty.

OBJECTIVES: In this study we measured regional myocardial work of the left ventricle in patients with dilated cardiomyopathy and examined the existence of regional differences in myocardial work. BACKGROUND: Left ventriculoplasty aims to improve the ejection fraction by excluding a region with decreased wall motion and decreasing wall tension. If regional differences in myocardial work are present, left ventriculoplasty will be more effective when a region with decreased myocardial work is excluded. METHODS: The study group consisted of 10 patients with idiopathic dilated cardiomyopathy. Regional work of the ventricle normalized to a unit volume of myocardium (RWM) is given as follows: RWM = -integral sigma(d)[ln(1/H)], where sigma is mean wall stress, and H is wall thickness of the region. After right-sided catheterization, left ventricular pressure was measured with a 3F micromanometer catheter. Echocardiography was performed simultaneously, and a short-axis view of the left ventricle at the level of the papillary muscles was obtained. The derived M-mode image was recorded with left ventricular pressure. sigma-ln(1/H) relations for the ventricle were delineated, and regional work of the interventricular septum and posteroinferior wall were determined. Relationships between regional work of the myocardium and wall thickness, interventricular septal regional work of the myocardium and right ventricular systolic pressure, and right ventricular ejection fraction were also studied. RESULTS: Interventricular septal regional work ranged from -0.84 to 3.34 mJ/cm3 (0.74 +/- 1.51 mJ/cm3). Posteroinferior wall regional work ranged from 1.59 to 4.29 mJ/cm3 (2.77 +/- 0.86 mJ/cm3). In the study group, interventricular septal regional work was lower than posteroinferior wall regional work (P <.05). In 8 of these 10 patients, interventricular septal regional work was lower than posteroinferior wall regional work. In the other 2 patients, conversely, interventricular septal regional work was higher than posteroinferior wall regional work. CONCLUSIONS: The existence of differences in regional work between the interventricular septum and the posteroinferior wall suggests the importance of the evaluation of regional work in the selection of an effective treatment for dilated cardiomyopathy.

Coronary artery bypass grafting with the right gastroepiploic artery and evaluation of flow with transcutaneous Doppler echocardiography.

From December 1988 to December 1992, 174 patients (160 men, 14 women, mean age 59.7 years, range 38 to 79 years) underwent coronary artery bypass grafting with the right gastroepiploic artery. The graft was anastomosed to the right coronary artery (n = 137), the circumflex artery (n = 18), the left anterior descending artery (n = 23), and the diagonal artery (n = 1). Three early deaths (1.7%) and one late death (0.6%) occurred. Graft patency and flow were evaluated noninvasively in 44 of the patients, selected at random between 1990 and 1993. They underwent transcutaneous Doppler echocardiographically to detect postoperative gastroepiploic artery flow. The patients were divided into two groups on the basis of the angiographic study: group I, good patency (n = 38); group II, poor flow in the graft or more than 75% stenosis of the anastomosis (n = 6). Biphasic Doppler flow signals were identified in 39 patients (88.6%) (group I, 35/38; group II, 4/6). The ratio of diastolic to total flow measured by time-velocity integral was 0.68 +/- 0.07 in group I and 0.32 +/- 0.09 in group II (p < 0.001). We conclude that the right gastroepiploic artery is an effective graft and that Doppler echocardiography may be a useful tool to noninvasively evaluate the patency and flow of the gastroepiploic artery graft as a coronary artery graft.

Tricuspid valve replacement with the bileaflet St. Jude Medical valve prosthesis.

Case histories of 39 patients who underwent tricuspid valve replacement with the St. Jude Medical prosthesis between June 1979 and August 1992 were reviewed in March 1993. The average patient age at the time of the operation was 46 +/- 11 years (range from 17 to 68 years). Concomitant mitral and/or aortic valve replacements were performed in 30 patients. All patients were given warfarin to maintain thrombotest between 10% to 25%. This number was between 2.8 to 1.6 times the control value in the International Normalized Ratio of prothrombin time. Three operative deaths occurred (7.7%). Among six late deaths, two patients died suddenly of unknown causes, and the remaining patient deaths were not valve-related. The actuarial survival rate at 14 years was 54.7%. Valve thrombosis occurred in one patient and was successfully treated with intravenous urokinase. This was the only valve-related complication (0.67%/patient-year). No reoperations were necessary in the tricuspid position. In conclusion, the St. Jude Medical valve is our choice of prosthesis for tricuspid valve replacement in adult patients who can receive proper anticoagulation therapy.

Open-position fixation of bioprostheses for more physiological performance. Fluoroscopic observations of leaflet movements in vivo.

A new model of the stent-mounted porcine aortic bioprosthesis was prepared with 0.625% glutaraldehyde while the valve was partially open. A radiopaque marker was attached to the center of the free margin of each leaflet so that the leaflet movements could be observed in an in vivo testing unit by fluoroscopic cinematography. This valve was compared with a porcine xenograft that currently is available commercially. While the heart was beating, the specially prepared leaflets showed some characteristics that contrasted with those of the currently used bioprosthesis. These features included (1) uniformity versus asymmetry of leaflet excursions under low flow conditions, (2) slower and more gradual closing (actual closing time averaging 536 msec versus 81 msec), and (3) more prolonged period of valve opening, the duration of opening averaging 60% versus 49% of the cardiac cycle. These features support the validity of open-position fixation as a means of further improving xenograft durability.

Optimal shape of prosthesis for tricuspid valve replacement.

To develop an optimal prosthesis for use in the tricuspid valve, we determined the change in cardiac performance associated with the change in shape of the anulus of the tricuspid valve using a metal ring of variable flat ratio (defined as the long/short axis). In experiment I in an isolated autoperfusion model with six dogs, the left ventricular stroke work under a constant left atrial pressure of 7 mm Hg were, in grams per beat per minute, 11.88 +/- 0.52 with a flat ratio of 1.0, 11.88 +/- 0.70 with a flat ratio of 1.3, 16.23 +/- 0.61 with a flat ratio of 1.6, and 11.22 +/- 0.38 with a flat ratio of 2.3 (mean +/- standard error of the mean). The volume was significantly higher with a flat ratio of 1.6 than with the other ratios (p < 0.05). In experiment II with six dogs in vivo, the blood flow of the pulmonary trunk artery was 0.57 +/- 0.03 L/min with a flat ratio of 1.0, 0.66 +/- 0.03 L/min with a flat ratio of 1.6, and 0.58 +/- 0.03 L/min with a flat ratio of 2.3; the flow was significantly larger with a ratio of 1.6 than with the other ratios (p < 0.05). Right ventriculography was performed in five dogs. The percentage of radial shortening of the apex close to the acute margin was 19.4% +/- 3.1% with a flat ratio of 1.0 and 49.2% +/- 5.1% with a flat ratio of 1.6 (p < 0.05). In conclusion, the best hemodynamic results were obtained with a flat ratio of 1.6, which showed more advantageous hemodynamics than do the ratios of conventional circular prostheses.

Effects of bilateral transvenous diaphragm pacing on hemodynamic function in patients after cardiac operations. Experimental and clinical study.

The effects of bilateral transvenous diaphragm pacing and intermittent positive-pressure ventilation on hemodynamic function were compared by animal experiment in 18 dogs and by clinical study in 14 patients during the postoperative period after cardiac operations. Aortic, pulmonary arterial, right atrial, and left atrial pressures (transmural) and aortic flow were increased by diaphragm pacing in the canine experiment. In dogs with induced tricuspid insufficiency, aortic pressure, right and left atrial pressures, and aortic blood flow increased, similar to the results obtained in the clinical study. Diaphragm pacing produced a sufficient tidal volume (7.2 to 12 ml/kg) for maintenance of normal blood gas levels in the patients, all of whom recovered spontaneous breathing without any weaning problems after 2 to 6 hours of diaphragm pacing. The catheter electrode used for stimulation was placed 30 mm away from the sinus node to avoid arrhythmias. Respiratory control by diaphragm pacing is hemodynamically superior to that by intermittent positive-pressure ventilation, and its efficacy is expected, especially in critical cases or in diseases or conditions in which the decrease in the load of the right heart affects the hemodynamic status of the patient.