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At least 307 records · Page 17Linked to original sources

Hemodynamic effects of medical antishock trousers during mechanical ventilation.

PURPOSE: To compare the hemodynamic effects of medical antishock trousers (MAST) inflation in mechanically ventilated patients with normal and poor left ventricular function. METHODS: Twelve patients requiring respiratory support were divided into two groups according to baseline transesophageal echocardiography (TEE) measurements: normal left ventricular dimensions and fractional area of contraction (FAC=61 +/- 5%) (n=7) and dilated cardiomyopathy with reduced FAC (21 +/- 1%) (n=5). All patients were studied when two successive levels of load (mild load by inflation of the leg compartment of MAST at 50 cmH2O and high load by adding the abdominal compartment of MAST inflated at 30 cmH2O) were applied. Global left ventricular systolic function was assessed on the TEE transgastric short-axis view. End-systolic wall stress (ESWS) was used as an indicator of left ventricular afterload. RESULTS: Total respiratory, lung and chest wall compliances were reduced by 48%, 51% and 27% respectively at the high load level (P < 0.05). Whereas no hemodynamic changes occurred at mild load, the high load level produced an increase in left ventricular afterload as evidenced by concomitant increases in diastolic arterial blood pressure (66 +/- 6 to 79 +/- 6 mmHg, P < 0.05) and ESWS (69 +/- 12 to 74 +/- 12 Kdyn x cm(-2) x m(-2), P < 0.05). In patients with dilated cardiomyopathy, this increase in afterload impaired the left ventricular systolic function and end-systolic area increased (19.0 +/- 2.5 to 21.4 +/- 2.9 cm2 x m(-2), P < 0.05) while FAC decreased (22 +/- 2 to 16 +/- 2%, P < 0.05). Left ventricular end-diastolic area remained unchanged during the study in both groups. CONCLUSION: MAST inflation impairs respiratory mechanics and global left ventricular systolic function in cardiac patients without changes in left ventricular preload.

Adult↗

Anaesthesia for caesarean section in a patient with myotonic dystrophy receiving warfarin therapy.

A 31-yr-old parturient with myotonic dystrophy and asthma presented for elective Caesarean section. The patient was receiving warfarin having had two previous episodes of thromboembolism. Anticoagulation was subsequently provided by heparin in the weeks prior to delivery. The combination of the patient's medical conditions and the continuing need for anticoagulation presented a considerable anaesthetic problem in planning anaesthesia and analgesia for both elective and emergency delivery. Heparin was discontinued on the day prior to surgery and restarted immediately after surgery. During surgery flowtron anti-embolitic boots were used. Warfarin therapy was recommenced on the seventh postoperative day. Anaesthesia for Caesarean section was provided using a combined spinal epidural technique using a separate needle, separate interspace method. Postoperative pain was relieved by using a continuous epidural infusion, transcutaneous nerve stimulation and diclofenac. No new neurological problems arose despite the use of epidural analgesia in the presence of heparin anticoagulation. This method of providing anaesthesia and postoperative analgesia without the use of opioids in an anticoagulated, asthmatic, myotonic parturient has not been described elsewhere.

Adult↗

[Reduced muscular oxygen tension and nerve impulse transmission from antishock hose. Reduction of oxygen tension in the tibial muscle and impulse transmission in the peroneal nerve from pneumatic -1 pressure from antishock hose].

OBJECT OF THE STUDY: The aim of the study was to assess, whether the pneumatic pressure of an antishock-trouser (AST) of 20-40 mm Hg induces a decreased oxygenation of the anterior tibial muscle and attenuates muscular response potential (MRP) of n. peronaeus profundus? METHODS: Among 22 normotensive, healthy volunteers the AST were tested by applying pressure values between 0 and 100 mm Hg and measuring the intracompartmental pressure, the muscular oxygen pressure as well as the MRP by electroneurographic means within a period of 6 hours. RESULTS: The median initial intracompartmental pressure value of the m. tibialis anterior was 12.0 mm Hg (Q25%/Q75%: 8.9/17.3), the muscular oxygen pressure 14.8 mm Hg (Q25%/Q75%: 11.5/22.0). Transmission of the pneumatic AST-leg segment pressure to the muscle: 97.7% (Q25%/Q75%: 89.2/99.8). Already in the low AST pressure field (20-40 mm Hg) a severe hypoxia occurred in one case. A reduction of MRP was noticed at an AST pressure rate of 10 mm Hg. In 5 of 6 cases AST pressure values of 60 mm Hg led to pathological pO2-values within 5-20 minutes. Almost without exception AST-pressure rates < 60 mm Hg resulted in an anoxia of the muscle and loss of the MRP. CONCLUSIONS: We should demand that the AST are only applied with models where the pressure generated within the single segments can be controlled by pressure gauge. The application of the AST seems to be justified for polytraumatised in severe haemorrhagic shock where the risk of a local tissue ischemia with systemical consequences must deliberately be accepted.

Adult↗

Sequential mechanical and pharmacological thromboprophylaxis in the surgery of hip fractures. A pilot study.

Two hundred and thirty-eight patients with femoral neck fractures were entered into a randomised pilot study comparing the use of sequential treatment by 'Flowtron DVT' garments in the perioperative period followed by Enoxaparin (Clexane-Rhône-Poulenc Rorer), and Enoxaparin alone. One hundred and ninety-three patients were excluded indicating the difficulty of achieving pure comparisons in this population. The remaining 44 were randomised: 21 received Enoxaparin from the time of admission, and 23 had sequential treatment. There was no statistically significant difference in the incidence of thromboembolism. Patient preference did not indicate a favoured treatment subjectively. The operation field was drier in the sequential group, although this did not reach significance. Sequential treatment was not shown to be better or worse than treatment with Enoxaparin, but the trends favoured sequential treatment rather than drug treatment alone. The technique allows the operation to be carried out without the problems produced by low dose heparins and mobilisation is not hindered by compression garments.

Adult↗

A combination of heparin and an intermittent pneumatic compression device may be more effective to prevent deep-vein thrombosis in the lower extremities after laparoscopic cholecystectomy.

BACKGROUND: The purpose of this study was to clarify the effect of a combination of heparin and an intermittent pneumatic compression device on thrombogenesis and platelet activation in the upper and lower extremities after laparoscopy. METHODS: A blinded study was performed on 30 patients. Patients were randomly injected with either heparin or physiological saline solution (PSS) subcutaneously. The intermittent compression boot was used during surgery. Plasma D-dimer (D-D), a marker of thrombogenesis, and b-thromboglobulin (b-TG), a marker of platelet activation, were measured in the upper and lower extremities. RESULTS: In the heparin group, D-Ds in the upper and lower extremities increased significantly 24 h after surgery, but they were significantly lower than those of the PSS group. b-TG in the lower extremities of patients in the PSS group increased significantly 24 h after surgery. CONCLUSION: A combination of low-molecular-weight heparin and intermittent pneumatic compression may be more effective to prevent deep-vein thrombosis in the legs.

Adult↗

Effects of "body compression" on parameters related to ascites formation: therapeutic trial in cirrhotic patients.

Decreased effective circulating blood volume is an important factor in ascites formation in liver cirrhosis. We designed a "body compression" apparatus as a means to restore effective blood volume and investigated its effectiveness in reducing ascites formation in cirrhotics in terms of its effect on parameters of ascites formation noted below. The subjects, eight cirrhotics with ascites and eight cirrhotics without ascites were given spironolactone (50-75 mg/day) and furosemide (40-80 mg/day) while they received a diet containing 85 mEq of sodium per day. All four limbs and the lower abdomen were compressed with constant pressure [height (cm) divided by 13.6 mmHg] once, for 3h, using stroke rehabilitation splints, while patients lay supine. In cirrhotics both with and without ascites, urine volume, urinary sodium excretion, and creatinine clearance during the body compression were greater than values during control (non-compression) periods (urine volume, means 285 vs 169 ml/3h; P < 0.001, urinary sodium excretion 15.8 vs 9.5 mEq/3h; p < 0.001, creatinine clearance 74 vs 59 ml/min, P < 0.001, respectively). The increased basal plasma renin activity, angiotensin II, aldosterone, and norepinephrine levels in all cirrhotics were significantly decreased by the body compression. In another group of six cirrhotics who received no diuretics or albumin, repeat body compression alleviated ascites in three with well preserved renal function, but was ineffective in three with markedly impaired renal function. These results suggest that the improvement in renal function brought about by the body compression is attributable to an increase in effective circulating blood volume. This maneuver may be a useful complementary therapy in patients with cirrhotic ascites with well preserved renal function.

Adult↗

Use of lower abdominal compression to combat orthostatic hypotension in patients with autonomic dysfunction.

The aim of this study was to investigate in patients with neurogenic orthostatic hypotension the mechanism and usefulness of abdominal compression to increase standing blood pressure. In three protocols, 23 patients underwent abdominal compression. Protocol 1 evaluated in a 40-60 degrees head-up-tilt position, the effect of abdominal compression on caval vein and femoral diameter, arterial blood pressure and hemodynamics. Protocol 2 documented the relationship between the level of compression and the arterial pressure response. Protocol 3 investigated the ability to maintain standing blood pressure by an elastic binder. During head-up-tilt, compression (40 mm Hg) resulted in a reduction in diameter of the caval vein (mean -2.6mm, range -1.4 to 0.6), without a change in femoral vein diameter. Stroke volume increased by 14 % (range -1 to 23) and blood pressure (systolic/diastolic) by 30/14 mmHg (range 7/2 to 69/36), both p < 0.05; 40 mmHg compression was associated with a higher pressure response than 20 mmHg (mean 18/8 mmHg, range 6/2 to 43/20 vs. mean 9/4 mmHg, range -1/0 to 18/8, p < 0.05). Elastic abdominal binding increased standing blood pressure with 15/6 mmHg (range -3/3 to 36/14, p < 0.05). We conclude that in patients with neurogenic orthostatic hypotension, abdominal compression increases standing blood pressure to a varying degree by increasing stroke volume.

Abdomen↗

Role of cardiopulmonary mechanoreceptors in the postural regulation of renin.

To change the stretch on cardiopulmonary mechanoreceptors, large shifts of blood in the capacity space were elicited by tilting and by exerting positive lower body pressure in the tilted position. Twelve volunteers underwent invasive hemodynamic studies and in 10 other subjects cardiac size was determined by radionuclide cardiography. In all 22 subjects tilting caused the expected increase of renin, which was abolished by lower body compression. Decompression caused renin to increase again. Right atrial pressure in invasive studies and end-systolic and end-diastolic counts in noninvasive studies showed a significant and strong negative correlation with renin and norepinephrine levels. Thus, the degree of stretch of the cardiopulmonary mechanoreceptors is a major determinant of reflex regulation of renin release in humans.

Adolescent↗

Nifedipine overdose.

A 59-year-old man ingested 900 mg of nifedipine. Profound hypotension, sinus and atrioventricular node dysfunction, and hyperglycemia resulted. The patient's condition responded favorably to aggressive treatment with intravenous fluids, calcium, and dopamine. Similar effects and response to therapy have been reported in 17 cases of verapamil overdose and are briefly summarized. The effects of nifedipine overdose are discussed, and preliminary recommendations about its management are offered. With increasing use of nifedipine and other calcium channel blockers, more incidents of overdose can be expected.

Atropine↗

A randomized trial of low-dose heparin and intermittent pneumatic calf compression for the prevention of deep venous thrombosis after gynecologic oncology surgery.

OBJECTIVE: Our aim was to determine the relative efficacy and complications of low-dose heparin and intermittent pneumatic calf compression for the prevention of postoperative venous thrombosis in patients undergoing surgery for gynecologic malignancy. STUDY DESIGN: Randomized trial comparing 107 patients treated with low-dose heparin to 101 patients treated with intermittent pneumatic calf compression was performed. All patients were evaluated with iodine-125 fibrinogen scanning of the legs. Clinical and laboratory variables associated with bleeding complications were recorded prospectively. RESULTS: Venous thrombosis was diagnosed in seven patients receiving low-dose heparin and in four receiving intermittent pneumatic calf compression (p = 0.54). Low-dose heparin patients received more blood transfusions postoperatively (p = 0.02), had increased volume of retroperitoneal drainage (p = 0.02), and the activated partial thromboplastin time was more frequently prolonged (p = 0.001). CONCLUSIONS: Low-dose heparin and intermittent pneumatic calf compression provide similar reduction in reducing the incidence of postoperative venous thrombosis. However, low-dose heparin is more frequently associated with postoperative bleeding complications.

Aged↗

An improved design of the pneumatic counter-pressure trousers.

Inflation of the circumferential pneumatic counter-pressure trousers was associated with the development of hemiparesis in a multiple trauma patient. We attribute this complication to the marked movement of the spinal cord that results from inflation of the circumferential abdominal compartment of the trousers. The design of the circumferential pneumatic counter-pressure trousers was recently modified so that the inflation portion of the abdominal compartment was restricted to the anterior portion of the abdomen. Inflation of the abdominal compartment of the modified trousers resulted in considerably less movement of the spine than with the trousers having the circumferential abdominal compartment.

Adult↗

Spaceflight and the telltale heart.

Cardiac arrhythmias have not been a common occurrence during manned spaceflights. Cardiovascular deconditioning, on the other hand, is a universal finding both during and after exposure to microgravity. Exercise capability is reduced only in the immediate postflight period as is cardiac output. These adaptive changes do not impair crew health or their ability to perform effectively in weightless flight. We believe that these effects are mediated by a decreased effective circulating blood volume and that they are completely reversible. In any case, an effective countermeasure is available to obviate or mitigate any untoward deconditioning effects on deorbit and return to Earth's gravity.

Adaptation, Physiological↗

Pressure developed under pressure garment.

To study how much pressure develops under a pressure garment, and how to obtain adequate effective pressure for scar treatment, we have used garments in combination with sponge and plastic plates in human volunteers. The pressures increased significantly when a sponge or sponge and plastic plate were used beneath the garment compared to pressures using a garment alone. In evaluations in patients with scar tissue on the limb, similar findings resulted.

Adolescent↗

Medical antishock trousers (MAST): a review.

A review of the literature on medical antishock trousers (MAST) is presented together with a report on their use at Hope Hospital, Salford. Their relevance in British emergency management and future uses are considered.

Blood Pressure↗

Crush syndrome complicating pneumatic antishock garment (PASG) use.

We present a case of severe compartment syndrome complicated by rhabdomyolysis and acute renal failure (crush syndrome) following the use of a pneumatic antishock garment (PASG) with survival of the patient. Review of the literature reveals one other similar case but without survival. The aetiology of the complication is discussed and recommendations for the safe use of the PASG are made.

Adult↗