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Deep vein thrombosis (DVT) is the most frequent complication after total hip arthroplasty, and proximal DVT is more likely to produce clinical pulmonary emboli than distal DVT. The authors have assessed the incidence and anatomic location of phlebographically proven fresh DVT following total hip arthroplasty in 855 patients over 39 years of age. Eight different regimens (2 warfarin, 3 aspirin, 1 dextran, 1 external pneumatic compression, and 1 dextran combined with external pneumatic compression) were evaluated and compared with an historical placebo control group from the same institution. No significant difference (P < .05) existed in proximal DVT incidence between the placebo group and any of the three aspirin groups, the dextran group, the external pneumatic compression group, or the dextran combined with external pneumatic compression group. In contrast, warfarin, given both in traditional and low-dose regimens, provided a significant reduction in proximal DVT compared with the placebo group (P < .001; statistical power, 0.84 and 0.99, respectively). The low-dose regimen had 10 times fewer bleeding complications than the traditional regimen. All prophylaxis regimens should be evaluated for both proximal and distal DVT formation, as well as for overall incidence. Low-dose warfarin offers the best protection against proximal thrombi of the agents studied, and it is also safer than traditional dosages of warfarin.
The purpose of this study was to investigate the effectiveness of intermittent pneumatic compression of the plantar venous plexus with the newly developed arteriovenous impulse system. Seventy-four patients about to undergo primary unilateral total hip arthroplasty for osteoarthrosis, all receiving a standard thrombosis prophylaxis regime of thigh-length anti-embolic stockings, 5,000 IU heparin delivered subcutaneously twice daily, and 400 mg hydroxychloroquine sulfate delivered twice daily, were entered in a prospective trial. The patients were allocated at random to also receive the arteriovenous impulse system on the foot of the operated side. On approximately postoperative day 12 bilateral ascending venography was performed. There were 44 patients in the nonpumped group and 30 patients in the pumped group. The incidence of deep venous thrombosis was 6.6% in the pumped group and 27.27% in the nonpumped group. The incidence of thrombosis was significantly lower in the pumped group (P < .025). The authors conclude that chemical prophylaxis plus the use of the mechanical, pneumatic, and arteriovenous impulse system reduces the incidence of thromboembolic complications further than chemical prophylaxis alone.
We report an accidental perforation of the left iliac artery and vein during lumbar discectomy in the kneeling position. During the surgical procedure, a brief and transient hypotension occurred, although the surgeon did not observe any abnormal bleeding in the operating field. In the recovery room, arterial blood pressure decreased, and tachycardia, pallor, and abdominal pain occurred. Retroperitoneal bleeding was suspected. Immediate fluid resuscitation was initiated, anesthesia was continued, and red blood cells were ordered. The use of medical antishock trousers enabled temporization until vascular surgeons were ready. An emergent laparotomy was performed to repair vascular injuries. The delayed symptoms, use of medical antishock trousers, and implications for anesthetists are discussed.
Hypertrophic scars are unsightly and can cause much distress to the sufferer. Pressure garments have been the preferred conservative management option for these scars for the last three decades. This paper reviews the history, underpinning theory and use of compression therapy in the management of hypertrophic scars particularly following burn injury. It is particularly aimed at clinicians who do not come into contact with this type of scarring frequently and are not familiar with its treatment. Other methods for managing hypertrophic scarring are also described briefly. Overall, there is a fair body of evidence to support the use of pressure garments, but it is not definitive research and further work is needed. However, the selection of any treatment must follow negotiation and agreement with the patient who will be required to continue treating their scars at home.
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Despite improvements in healing rates venous ulcer disease still carries significant morbidity and cost. Any therapy that further improves healing rates is worthy of consideration. The recognised effects of intermittent pneumatic compression (IPC) on both arterial and venous circulation suggest that its use may confer significant benefits to venous ulcer healing. This study investigates the potential additive effects of adjuvant IPC on the healing and subsequent prevention of venous ulcers. Some improvement in the rate of healing in venous ulcers is noted. These findings are set against a background of very high healing rates in both treatment and control groups. No benefit is seen to accrue if IPC is used as an adjuvant therapy to help prevent recurrence of ulcers although the study period is very short.
The operational characteristics of eight intermittent pneumatic compression systems were evaluated. Considerable differences between the pressure/time curves were found when different pumps were compared. The pressure attained in the garments varied from 6 to 124 mmHg and the rate of inflation from less than 1 to 9 mmHg per second.
A better understanding of lower limb haemodynamics and the effects of intermittent pneumatic compression on the lower limb has led to an increasing awareness of the potential value of intermittent pneumatic compression in both venous and arterial disease. Intermittent pneumatic compression can be used in both the primary and secondary care settings, with its advantages being further enhanced by excellent patient compliance and very low rate of complications. Intermittent pneumatic compression has a proven role in the prophylaxis of deep vein thrombosis and there is some evidence that it is a useful adjunct in the management of venous ulcer disease. With laboratory and more recent clinical studies demonstrating augmentation of arterial inflow with intermittent pneumatic compression, its use in arterial diseases is being increasingly explored. Further studies are needed to define the precise role of intermittent pneumatic compression in arterial disease but any treatment regimen which reduces the need for referral or intervention in the claudicant or critically ischaemic limb will be a valuable addition to those managing arterial disease.
BACKGROUND: Deep venous thrombosis (DVT) in severely injured patients is a life-threatening complication. Effective and safe thromboprophylaxis is highly desirable to prevent DVT. Low-dose heparin (LDH) and sequential compression device (SCDs) are the most frequently used methods. Inappropriate use of these methods because of the nature or site of critical injuries (eg, brain lesion, solid visceral or retroperitoneal hematoma, extremity fractures) may lead to failure of DVT prophylaxis. STUDY DESIGN: A prospective study was performed to evaluate the efficacy of a policy of aggressive use of LDH and SCDs in patients who are at very high risk for DVT. From January 1996 to August 1997, 200 critically injured patients were followed by weekly Doppler examinations to detect DVT at the proximal lower extremities. Only 3 patients did not receive any thromboprophylaxis. SCDs were applied in 97.5% and LDH was administered to 46% of the patients; 45% had both. RESULTS: DVT was found in 26 patients (13%). The majority (58%) developed DVT within the first 2 weeks, but new cases were found as late as 12 weeks after admission. The incidence of DVT was the same among patients who had SCDs only or a combination of LDH and SCDs. Mechanism of injury, type and number of operations, site of injury, Injury Severity Score, and the incidence of femoral lines were not different between patients with and without DVT. Differences were found in the severity of injury to the chest and the extremities and the need for high-level respiratory support. Patients with DVT had prolonged ICU and hospital stays (on average, 34 and 49 days, respectively) and a high mortality rate (31%). CONCLUSIONS: The incidence of DVT remains high among severely injured patients despite aggressive thromboprophylaxis. A combination of LDH and an SCD showed no advantage over SCD alone in decreasing DVT rates. Risk factors in this group of patients who are already at very high risk are hard to detect; Doppler examinations are justified for surveillance in all critically injured patients. Current methods of thromboprophylaxis seem to offer limited efficacy, and the search for more effective methods should continue.
Pulmonary air embolism is a well-known consequence of surgery, trauma, diving, and aviation. This article reviews the physiological effects, means of detection and methods of prevention and treatment of pulmonary air embolism. The primary physiological effects are elevated pulmonary artery pressures, increased ventilation-perfusion inhomogeneity, and right ventricular failure. The degree of physiological impairment depends on the volume of gas entrained, the rate of entrainment, the type of gas entrained, and the position of the patient when the embolism occurs. Transesophageal echocardiography is the most sensitive method of detection, but it is invasive. Precordial Doppler ultrasound is almost as sensitive and poses no risk to the patient. End-tidal carbon dioxide monitoring is used on all patients and is a moderately sensitive method of detection, which is useful during surgeries that have a low incidence of air embolism. For high-risk procedures, precordial Doppler ultrasound and a multi-orifice right heart catheter should be used to detect and treat pulmonary air embolism. Prevention measures include volume expansion, careful positioning, positive end-expiratory pressure, military anti-shock trousers, and jugular venous compression. Treatment of pulmonary air embolism includes flooding the surgical site with saline, controlling sites of air entry, repositioning the patient with the surgical site below the right atrium, aspiration of air from a central venous catheter, cessation of inhaled nitrous oxide, and resuscitation with oxygen, intravenous fluids, and inotropic agents. Some hypotheses on the effects of air in the pulmonary vasculature and investigational treatment options are discussed.
This pilot study assessed the effectiveness of external pneumatic compression (EPC) with gradient elastic stockings (GES) and low dose heparin (LDH) in the prevention of deep vein thrombosis (DVT) in acute spinal cord injured (SCI) patients in the first 14 days following injury. Twenty-one consecutive patients within 48 hrs of injury with acute C2 through T12 motor complete or nonfunctional motor incomplete spinal cord lesions were enrolled. 125 I fibrinogen scanning was performed daily. A positive scan was confirmed by venography. Thrombosis was demonstrated in 1/19 patients. A control group from a previous study confirmed thrombosis in 6/17 patients (p = 0.04). Comparison of extent of thrombosis demonstrated a reduction in the treated group (p = 0.02). This pilot study demonstrates that EPC with GES plus LDH may be an effective prophylactic regimen in these patients.
1. In a group of 40 patients with orthostatic intolerance due to hypotension and/or tachycardia, we have compared the pathogenetic roles of impaired contractility of the arterioles and the veins by measuring contractile responsiveness of the arterioles, reflected by increases in diastolic blood pressure and of the veins reflected by measurements of reduction in venous diameter during intravenous noradrenaline infusions. 2. Compared with 27 healthy subjects, patients with diffuse autonomic insufficiency showed striking supersensitivity in diastolic blood pressure (six out of eight) and venous constrictive responses (seven out of eight patients) to noradrenaline, consistent with impaired arteriolar and venous innervation. 3. In contrast, the patients with hyperadrenergic orthostatic hypotension (n = 16) and orthostatic tachycardia (n = 16) showed diastolic blood pressure responses to noradrenaline that were almost invariably within the 95% confidence limits of the changes in normal subjects but supersensitive constrictive responses of foot veins in 22 of 32 subjects and subnormal venous responses in two individuals. The rate of noradrenaline infusion calculated to cause 50% of maximal venous constriction (the ED50) was significantly lower in the patients [mean (SEM) 6.8 (1.9) ng/min] than in the normal subjects [mean (SEM) 23.2 (3.0) ng/min, P < 0.025]. 4. The finding of significantly supersensitive foot vein constrictive responses to noradrenaline infusion in the patients of all three groups and supersensitive blood pressure responses exclusively in the patients with diffuse autonomic insufficiency indicates that venous pooling in the legs was the predominant pathogenetic mechanism of orthostatic intolerance in all three types of patients studied. 5. Correction of the orthostatic hypotension and/or tachycardia by external compression in virtually all patients confirmed this conclusion.
Orthostatic intolerance (OI) is the most serious symptom of cardiovascular deconditioning induced by head-down bed rest or weightlessness. Wearing venoconstrictive thigh cuffs is an empirical countermeasure used by Russian cosmonauts to limit the shift of fluid from the lower part of the body to the cardio-cephalic region. Our aim was to determine whether or not thigh cuffs help to prevent orthostatic hypotension induced by head-down bed rest. We studied the effect of thigh cuffs on eight healthy men. The cuffs were worn during the day for 7 days of head-down bed rest. We measured: orthostatic tolerance (stand tests and lower body negative pressure tests), plasma volume (Evans blue dilution), autonomic influences (plasma noradrenaline) and baroreflex sensitivity (spontaneous baroreflex slope). Thigh cuffs limited the loss of plasma volume (thigh cuffs: -201 +/- 37 mL vs. control: -345 +/- 42 mL, P < 0.05), the degree of tachycardia and reduction in the spontaneous baroreflex sensitivity induced by head-down bed rest. However, the impact of thigh cuffs was not sufficient to prevent OI (thigh cuffs: 7.0 min of standing time vs. control: 7.1 min). Decrease in absolute plasma volume and in baroreflex sensitivity are known to be important factors in the aetiology of OI induced by head-down bed rest. However, dealing with these factors, using thigh cuffs for example, is not sufficient to prevent OI. Other factors such as venous compliance, microcirculatory changes, peripheral arterial vasoconstriction and vestibular afferents must also be considered.
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OBJECTIVE: To evaluate the feasibility, safety and effectiveness of the non-pneumatic anti-shock garment for resuscitation and haemostasis following obstetric haemorrhage resulting in severe shock. DESIGN: During a six-week period, the author served a locum tenens as the obstetrician consultant for the Memorial Christian Hospital, Sialkot, Pakistan. All women who suffered from severe obstetric haemorrhage were managed with the anti-shock garment as the first intervention. The data for this report were collected from hospital chart review. SETTING: Sialkot is a city of about three million and Memorial Christian Hospital is one of two major obstetric hospitals. There is no blood bank at Memorial Christian Hospital or elsewhere in Sialkot. The Memorial Christian Hospital laboratory is able to draw donor blood, type and cross match blood, and process it for transfusion 24 hours per day. POPULATION: During the six weeks of this study, in June and July 2001, there were 764 deliveries and 34 other admissions within a week following deliveries outside the hospital. Seven women with obstetric haemorrhage who developed severe shock were managed with the anti-shock garment. One woman, who was later found to have mitral stenosis, developed dyspnea upon placement of the anti-shock garment and therefore it was removed within 5 minutes. This report concerns the six women who were able to tolerate the anti-shock garment without untoward symptoms. METHODS: As soon as severe shock was recognised in the hospital, the anti-shock garment was placed. Crystalloid solutions were given intravenously over the first hour at a rate of 1500 mL per estimated litre of blood loss, then at a maintenance rate of 150 mL/hour. Vital signs every 15 to 30 minutes, hourly urine output and intermittent oxygen saturation were used to monitor patients during the use of the anti-shock garment. When sufficient blood transfusion had been given to restore the haemoglobin to >7 g/dL, the anti-shock garment was removed in segments at 15-minute intervals with documentation of vital signs before removal of each subsequent portion. MAIN OUTCOME MEASURES: Restoration of mean arterial pressure of 70 mmHg and clearing of sensorium were considered as signs of effective resuscitation. Haemorrhage was considered controlled if the blood loss was less than 25 mL/hour. Morbidity included any complications noted in the medical chart. RESULTS: Restoration of blood pressure and improvement of mental status occurred within 5 minutes in two patients who were pulseless and three who were unconscious or confused. All patients had improvement of mean arterial pressure to greater than 70 mmHg within 5 minutes. Duration of anti-shock garment use ranged from 12 to 36 hours and none of the six women had significant further bleeding while the anti-shock garment was in place. Patients were comfortable during use of the anti-shock garment and no adverse effects were noted apart from a transient decrease in urine output. CONCLUSIONS: The anti-shock garment rapidly restored vital signs in women with severe obstetric shock. There was no further haemorrhage during or after anti-shock garment use and the women experienced no subsequent morbidity. A prospective randomised study of the anti-shock garment for management of obstetric haemorrhage is needed to further document these observations.
There are many reports of how IPC is used effectively in the clinical setting; including the prevention of deep venous thrombosis, improvement of circulation in patients with lower extremity arterial diseases, reduction of lymphoedema, and the healing of venous ulcers. However, despite the widely accepted use of IPC, it is still unclear how IPC actually exerts its beneficial effects. The exact physiological mechanisms of action are unknown. The clinical utility of IPC and the putative mechanisms by which IPC could exert its therapeutic effect will be reviewed. The paper will examine the mechanical effects of IPC exerted on the lower extremity, and the subsequent biochemical changes in the circulation. In vitro studies of the effects of mechanical stress such as compressive strain and shear on cultured endothelial cells, and their clinical relevance to IPC will also be reviewed.
Hand-held pressure algometry usually assesses pressure-pain detection thresholds and provides little information on pressure-pain stimulus-response function. In this article, a cuff pressure algometry for advanced pressure-pain function evaluation is proposed. The experimental set-up consisted of a pneumatic tourniquet cuff, a computer-controlled air compressor and an electronic visual analogue scale (VAS) for constant pain intensity rating. Twelve healthy volunteers were included in the study. In the first part, hand-held algometry and cuff algometry were performed over the gastrocnemius muscle with constant compression rate. In the second part, the cuff algometry was performed with different compression rates to evaluate the influence of the compression rate on pain thresholds and other psychophysical data. Pressure-pain detection threshold (PDT), pain tolerance threshold (PTT), pain intensity, PDT-PTT time and other psychophysical variables were evaluated.Pressure-pain detection thresholds recorded over the gastrocnemius muscle with a hand-held and with a cuff algometer, were 482 +/- 19 kPa and 26 +/- 1.6 kPa, respectively. Pressure and pain intensities were correlated during cuff algometry. During increasing cuff compression, the subjective pain tolerance limit on VAS was 5.6 +/- 0.95 cm. There was a direct correlation between the number of compressions, the compression rate and pain thresholds. The cuff algometry technique is appropriate for pressure-pain stimulus-response studies. Cuff algometry allowed quantification of psychophysical response to the change of stimulus configuration.