Jan Modig

Thromboembolism after Total Hip Replacement: Role of Epidural and General Anesthesia

The effects of continuous epidural anesthesia and of general anesthesia on the incidence of thromboembolism following total hip replacement were studied. Sixty patients were randomly allotted to one of two groups receiving either epidural or general anesthesia. Epidural anesthesia (N = 30) consisted of 0.5% bupivacaine with epinephrine intraoperatively; for pain relief in the postoperative period (24 h), 0.25% bupivacaine with epinephrine was given every 3 h. General anesthesia (N = 30) consisted of controlled ventilation with N2O-O2 and intravenous fentanyl and pancuronium bromide; postoperatively, narcotic analgesics were given intramuscularly on demand for pain relief. Significantly lower frequencies were found following epidural anesthesia than after general anesthesia in deep venous thrombosis involving the popliteal and femoral veins (13% and 67%, respectively), deep venous thrombosis involving both calf and thigh veins (40% and 77%), and pulmonary embolism (10% and 33%). Possible explanations for these differences include increased circulation in the lower extremities, less tendency for intravascular clotting to occur, and more efficient fibrinolysis in association with continuous epidural anesthesia. The decrease in blood loss associated with epidural anesthesia with lower transfusion requirements also might play a role. Epidural analgesia prolonged into the postoperative period, in addition to other appropriate thromboprophylactic measures, should be of value in patients undergoing operations associated with a high risk of thromboembolic complications.

Arterial Hypotension and Hypoxaemia During Total Hip Replacement: The Importance of Thromboplastic Products, Fat Embolism and Acrylic Monomers

Thirteen patients submitted to total hip replacement surgery by the Charnley technique were studied. Operations were performed under epidural analgesia with the patients awake and breathing air. During the surgical procedure, the magnitude of tissue‐thromboplastic activity, the amount of fat globules, the presence of bone marrow cells and the concentrations of acrylic monomers were determined in the pulmonary arterial blood. Simultaneously, arterial blood gases and blood pressure were monitored.

Effect of Epidural Versus General Anaesthesia on Calf Blood Flow

The arterial inflow into the calf, venous emptying rate and venous capacity were studied by means of venous occlusion plethysmography on the non‐operated leg in two groups of patients undergoing total hip replacement. One group of eight patients received epidural blockade intraoperatively, which was prolonged postoperatively for pain relief, while the other group of eight patients was given general anaesthesia with intermittent positive‐pressure ventilation intraoperatively and parenteral analgesics for pain relief in the postoperative period. The calf blood flow and venous capacity were lower in patients receiving general anaesthesia when measured at the end of surgery and significantly lower in this group when measured 3 h postoperatively. The sustained reduction of flow in the deep veins of the lower limb might be a significant contributory factor in the initiation of deep venous thrombosis. In three of the eight patients in the general anaesthesia group, the venous emptying rate and venous capacity had decreased 3 h postoperatively to a very low level, indicating thrombus formation in immediate association with the surgery.

Effectiveness of dextran 70 versus Ringer's acetate in traumatic shock and adult respiratory distress syndrome.

During a 3-yr period, 31 adult victims of severe traumatic shock were enrolled in a prospective randomized investigation of the relative effectiveness of dextran 70 vs. Ringers acetate to treat shock and protect against trauma-induced adult respiratory distress syndrome (ARDS). Fourteen patients were given dextran 70 and Ringers acetate to compensate for interstitial fluid loss, and whole blood as required; the remaining 17 patients received three to four times the total fluid volume of Ringers acetate given in the former group, and whole blood as required. Hemodynamics improved significantly more rapidly in the dextran group. In the 7 to 8-day post-trauma period, no patient in the dextran group developed ARDS, compared to five cases of ARDS in the Ringers acetate group. Also, the cardiac index of dextran patients was significantly higher, and patients challenged with 0.5 L of dextran 70 showed a significantly higher increase in cardiac index than those challenged with 2 L of Ringers acetate. It is concluded that in the severely traumatized patient, a fluid program based on dextran 70 is superior to Ringers acetate alone. Furthermore, patients should continue on a fluid program containing dextran 70 to counteract unrecognized, hypovolemia. Our results support the assumption that early aggressive shock treatment with dextran 70, followed by continued dextran administration in the post-trauma period might prevent complications such as ARDS.

Pulmonary Microembolism During Intramedullary Orthopaedic Trauma

Patients undergoing prosthetic hip surgery by the Charnley method were given 51Cr labelled platelets and 125I labelled fibrinogen the day before the operation. External monitoring of both kinds of radioactivity over the right lung was performed during the surgical procedure. A transient accumulation of 51Cr radioactivity over the lung was noted during broaching of the femoral bone marrow and after impaction of the femoral prosthetic stem. Transient trapping of 125I radioactivity was also recorded during the latter period. Arterial oxygen tension (Pao2) dropped significantly after impaction of the femoral prosthesis. The correlation coefficient was ‐0.97 between deposition of 125I radioactivity in the lung and the Pao2 reduction occurring after insertion of the femoral prosthesis. These results might indicate a pulmonary microembolism occurring during this stage of the operation, with concomitant pulmonary dysfunction.

Signs of neutrophil and eosinophil activation in adult respiratory distress syndrome.

Circulating levels of lactoferrin, a specific granule protein of neutrophilic leukocytes, and eosinophil cationic protein (ECP), a specific granule protein of eosinophilic leukocytes, were serially measured in 19 patients at risk for adult respiratory distress syndrome (ARDS). Those patients who developed ARDS had significantly higher concentrations of both proteins than the patients without signs of ARDS. High ECP levels were observed in spite of peripheral eosinopenia. The lactoferrin levels were also increased in relation to circulating numbers of neutrophils. These findings are consistent with an enhanced turnover and/or activity of eosinophils and neutrophils in ARDS and thereby support other clinical and experimental observations suggesting a central pathophysiologic role for granulocytes in ARDS. No relation was found between ARDS or serum concentrations of lactoferrin or ECP and degree of complement consumption, suggesting that other mechanisms besides complement activation may underlie granulocyte activation in ARDS.

Advantages of dextran 70 over ringer acetate solution in shock treatment and in prevention of adult respiratory distress syndrome. A randomized study in man after traumatic-haemorrhagic shock

Twenty-three patients aged 20-58 years in a serious state of shock and suffering from major pelvic and femoral fractures sustained in traffic accidents were studied. As initial fluid management, either dextran 70 (1000-1500 ml) together with Ringers acetate solution (2000-3000 ml), or Ringers acetate alone (5000-8000 ml), was administered on a random basis. Thus, 12 patients received dextran and 11 patients crystalloid treatment to counteract shock. Both groups were given whole blood. The resuscitation time--i.e. the interval from the start of fluid therapy until a stable circulatory condition was achieved--was significantly shorter (P less than 0.001) in the dextran group (108 +/- 18 min; mean +/- S.D.) than in the Ringer group (170 +/- 43 min). During the post-resuscitative observation period of 6 days the dextran patients were given 500 ml of dextran daily, while the Ringer group did not receive any colloidal solution. To maintain a stable circulation and a urinary output above 50 ml/h the Ringer patients required significantly more (P less than 0.001) crystalloid solution (910 +/- 300 ml) daily than the dextran patients (460 +/- 400 ml). The frequency of adult respiratory distress syndrome (ARDS) was significantly lower (P less than 0.05) in the dextran group (0 of 12) than in the Ringer group (4 of 11). Thus, in the initial treatment of traumatic-haemorrhagic shock and in the post-resuscitative period dextran 70 would seem of advantage over Ringers acetate both in shortening the shock period and in reducing the frequency of adult respiratory distress syndrome.

Respiration and Circulation after Total Hip Replacement Surgery

The cardiopulmonary effects of two different types of postoperative analgesic regimens were compared in 31 cardiorespiratorily healthy patients subjected to total hip replacement surgery. The investigation was performed preoperatively on the morning of the day of surgery and during the first 3 days postoperatively. All patients received continuous lumbar epidural analgesia preoperatively, during surgery and up to the end of the first measurement period, which started 2.5 h after surgery. Ten patients were subsequently given pentazocine (Fortalgesic®) intramuscularly on demand for pain relief throughout the investigation, while 14 patients received 0.4% plain lidocaine (Xylocain®), and seven patients 0.4% lidocaine with adrenaline (1/400,000) as a continuous lumbar epidural drip for analgesia throughout the investigation.

Complement activation and increased alveolar-capillary permeability after major surgery and in adult respiratory distress syndrome

The concentrations of C3a des Arg were measured in bronchoalveolar fluid (BAL) and plasma from 12 patients with adult respiratory distress syndrome (ARDS). Compared with 32 controls, all patients had increased BAL fluid levels (p < .001), and nine of 12 had increased plasma levels (p < .001) of this split product from the third complement component. Reduced total hemolytic activity (CH50) in serum was seen in five patients (p < .01). As an indication of damage to the alveolar-capillary barrier, ten of the 12 ARDS patients had elevated albumin concentrations in BAL fluid (p < .001). These signs of complement activation and lung tissue damage are not specific for ARDS. Thus, in 15 patients investigated preoperatively and postoperatively, we found that major surgery induced a significant increase of BAL fluid C3a (p < .01) and plasma C3a (p < .02), a significant reduction of CHso (p < .001), and a significant increase of BAL fluid albumin (p < .02). Similar values of CHso and plasma C3a were seen in ARDS and after surgery (p > .05). Of the 12 ARDS patients, eight had increased BAL fluid concentrations of C3a (p < .001), and ten had increased BAL fluid levels of albumin (p < .001) compared with the post-surgical patients.Measuring complement consumption in blood by these techniques is of limited value in ARDS due to the lack of specificity. BAL fluid albumin has a similar degree of sensitivity and specificity for ARDS as does BAL fluid C3a. Measuring BAL fluid levels of albumin is a simple and fast method; therefore, it potentially has a practical and clinical value in obtaining information about the development of ARDS.

Sudden Pulmonary Dysfunction in Prosthetic Hip Replacement Surgery: A Case Report

In a 51‐year‐old female patient (suffering from necrosis of the femoral head), the mean pulmonary arterial pressure rose from 25 to 31 mmHg, and the mean arterial blood pressure fell from 100 to 50 mmHg 20‐25 seconds after the insertion of a femoral prosthesis into the medullary cavity of the femur by the Charnley technique. Airway resistance increased from 9.0 to 12.3 dyn.s.cm‐5 at an airflow of 0.5 l/s. Venous admixture during air‐ventilation increased from 17 to 52%, causing an arterial desaturation from 95 to 74% oxygen saturation.