Barbara Urquhart

Post‐Operative Delirium: Predictors and Prognosis in Elderly Orthopedic Patients

To compare the effect of post‐operative analgesia using epidural versus intravenous infusions on the incidence of delirium after bilateral knee replacement surgery in elderly patients. Additional risk factors and impact on post‐operative recovery were also assessed.

Postoperative Prophylactic Administration of β-adrenergic Blockers in Patients at Risk for Myocardial Ischemia

Perioperative myocardial ischemia (MI) is associated with postoperative cardiac morbidity. Postoperative sympatholysis may reduce the incidence of MI. This study evaluated such a reduction postoperatively with the administration of prophylactic &bgr;-blockers in patients undergoing elective total knee arthroplasty with epidural anesthesia and postoperative epidural analgesia. One hundred seven patients were preoperatively randomized into two groups, control and &bgr;-blockers, who received postoperative esmolol infusions on the day of surgery and metoprolol for the next 48 h to maintain a heart rate less than 80 bpm. Patients were followed for ST segment depression by using a Holter monitor and adverse cardiac outcomes. Postoperative electrocardiographic ischemia was significantly more prevalent in the control group compared with the &bgr;-blocker group during esmolol blockade (0 of 52 vs 4 of 55;P = 0.04) and tended to be more common in the control group the next two days (8 of 55 vs 3 of 52;P = 0.135). In addition, the number of ischemic events (control, 50; &bgr;-blockers, 16) and total ischemic time (control, 709 min; &bgr;-blocker, 236 min) were also significantly different from the control group. Myocardial infarctions and cardiac events were more common in the control group, but these differences were not significant. Our results suggest that the use of prophylactic &bgr;-blocker therapy may reduce the incidence of postoperative MI. Implications Prophylactic &bgr; adrenergic blockade administered after elective total knee arthroplasty was associated with a reduced prevalence and duration of postoperative myocardial ischemia detected with Holter monitoring.

The efficacy of antifibrinolytics in the reduction of blood loss during complex adult reconstructive spine surgery.

Study Design. Controlled study to assess the efficacy of aprotinin and Amicar in reducing blood loss during complex spinal fusions. Objectives. To compare blood loss and the clotting profile with a thromboelastogram in patients with spinal deformities undergoing sequential anterior and posterior spinal fusions treated intraoperatively with either aprotinin or Amicar. Summary of Background Data. Spinal fusion for correction of adult spinal deformities is associated with large blood losses despite the implementation of multiple factors to reduce this blood loss. The antifibrinolytics aprotinin and Amicar have both been shown to reduce blood loss in other surgical procedures with the potential for large blood loss. Hence, we compared their efficacy for reducing blood loss in complex spinal fusions. Methods. Sixty patients for elective sequential anteroposterior thoracolumbosacral fusions were randomly assigned to three groups: control, aprotinin, and Amicar. Patients were assessed for blood loss, transfusion requirements, postoperative complications, and coagulation profile using a thromboelastogram. Results. The study demonstrated a significant reduction in total blood loss (aprotinin 3628 mL, Amicar 4056 mL, control 5181 mL) and transfusion requirements using the half-dose aprotinin regimen compared with Amicar or control. Aprotinin also preserved the thromboelastogram mean clot formation time, clot strength, and clotting index compared with Amicar or control. Conclusions. For complex spinal operations with large blood losses, the half-dose aprotinin regimen will reduce blood loss and the need for blood components and may have a role in reducing postoperative lung injury.

The effect of two levels of hypotension on intraoperative blood loss during total hip arthroplasty performed under lumbar epidural anesthesia

The degree of induced hypotension necessary to achieve a significant reduction in intraoperative blood loss has never been defined. Forty patients undergoing primary total hip arthroplasty during epidural anesthesia by a single surgeon were randomly assigned to have mean arterial pressure maintained at 50 ± 5 mm Hg or 60 ± 5 mm Hg throughout surgery. Intraoperative blood loss was 179 ± 73 mL in the 50 mm Hg group and 263 ± 2 98 mL in the 60 mm Hg group (P = 0.004). Subjectively, there was more bleeding during surgery in the 60 mm Hg group during dissection of the hip joint (P = 0.0026) and while reaming the acetabulum (P = 0.0001) and femur (P = 0.0001). No difference in transfusion requirements, postoperative hematocrit, or duration of surgery was noted. A difference in mean arterial blood pressure of 10 mm Hg from 50 to 60 mm Hg during surgery for total hip arthroplasty under epidural anesthesia has a measurable effect on intraoperative blood loss.

Factors Influencing Deep Vein Thrombosis Following Total Hip Arthroplasty Under Epidural Anesthesia

To determine intraoperative factors which may influence deep vein thrombosis rate, we studied surgeries performed by one surgeon on 441 consecutive patients undergoing primary total hip arthroplasty under epidural anesthesia. Operative limb venography was performed on the fourth or fifth postoperative day in 381 patients, who received 650 mg of aspirin daily as the only postoperative thromboprophylaxis. Of 381 (15%) patients, 58 had a positive venogram; 13 (3%) had proximal thrombi. Of 178 patients (9.5%) with surgery lasting less than 70 min, 17 developed deep vein thrombosis whereas 41 of 203 patients (20.3%) with surgery lasting more than 70 min developed deep vein thrombosis (P < 0.05). Corresponding proximal deep vein thrombosis rates increased from 1.7% to 4.9%. Deep vein thrombosis was observed in 12.5% of patients receiving intravenous low-dose epinephrine, 10.3% receiving intravenous sodium nitroprusside, 14.5% receiving both low-dose epinephrine and sodium nitroprusside concurrently, and 25% receiving intravenous fluid alone. Proximal deep vein thrombosis rates were 2.4%, 0%, 1.45%, and 9.3% in these groups, respectively. These data suggest that the intraoperative management of both surgery and anesthesia influence rates of deep vein thrombosis following total hip arthroplasty.

Back Pain after Epidural Anesthesia with Chloroprocaine

BackgroundChloroprocaine has been associated with severe back pain after epidural anesthesia. Factors proposed to contribute to this problem are: 1) the preservative disodium ethylenediaminetetraacetlc acid (EDTA), 2) large volumes of chloroprocaine, 3) low pH of chloroprocaine, and 4) local Infiltration with chloroprocaine. MethodsUsing a prospective, balanced, randomized study design, 100 patients aged 18–65 yr who were undergoing outpatient knee surgery during continuous epidural anesthesia received one of five local anesthetics (all containing epineph-rine 1:200,000). Group I received a bolus of 30 ml 2% lldocaine, followed by 10 ml every 45 min. Group II received 15 ml of 3% chloroprocaine (containing EDTA), plus 5 ml every 45 min. Group III received 30 ml of 3% chloroprocaine plus 10 ml every 45 min. Group IV received 30 ml of 3% chloroprocaine (containing metabisulfite as the preservative but no EDTA) plus 10 ml every 45 mln. Group V received 30 ml of 3% chloroprocaine with the pH adjusted to 7.3, plus 10 ml every 45 min. After the anesthesia dissipated and before any analgesic agents were given, the patients were asked to rank maximum knee and back pain on a visual analog scale (0–10) and to give a description of back pain. A telephone interview was conducted 24 h after surgery to determine if back pain returned. Back pain scoring was assessed using a verbal analog scale. ResultsAfter dissipation of anesthesia, the back pain reported by patients fell into two distinct categories. Type 1 pain was described commonly as superficial and localized to the site of needle insertion. There was no difference among groups in incidence of type 1 pain. Type 2 pain was described as deep, aching, burning, and poorly localized in the lumbar region (5% of the patients in group I,10% in groups II and IV, 50% in group III, and 25% in group V). The incidence of type 2 pain was significantly greater in group III than in groups I, II, or IV. Group III also had a significantly greater mean visual analog scale pain score (types 1 and 2) than all other groups. ConclusionsLarge doses (≤ 40 ml) of chloroprocaine containing EDTA resulted in a greater incidence of deep burning lumbar back pain. Using 25 ml or less of the same solution resulted in an incidence of both types 1 and 2 postepidural anesthesia back pain similar to that in the lldocalne control group.

Reduction in postoperative pain after spinal fusion with instrumentation using intrathecal morphine.

Study Design. The efficacy of intrathecal (spinal) morphine in the treatment of pain after posterior spinal fusions was assessed. Objective. To investigate improved posterior pain control with fewer side effects in patients with posterior spinal fusions. Summary of Background Data. After multilevel spinal fusion with instrumentation, patients experience considerable pain that is difficult to treat. Methods. For this study, 65 patients undergoing elective multilevel posterior spinal instrumentation were randomized to receive spinal morphine as follows: 10 &mgr;g/kg, 20 &mgr;g/kg, or none. These patients were assessed after surgery for pain control and narcotic-associated complications. Results. The patients who received 20 &mgr;g/kg of spinal morphine were more comfortable immediately after surgery, remained pain free for a longer period, and required significantly less additional narcotic. These patients also had fewer respiratory complications. Conclusions. Relatively high-dose spinal morphine administration provides simple, reliable postoperative pain control after posterior spinal fusions. This may contribute to reduced postoperative respiratory morbidity and an improved outcome.

Factors affecting deep vein thrombosis rate following total knee arthroplasty under epidural anesthesia.

A retrospective review was performed of 448 consecutive patients undergoing primary, unilateral, bicondylar, and cemented total knee arthroplasty under epidural anesthesia by three surgeons to determine factors contributing to deep vein thrombosis rate. All had venography on the fourth or fifth postoperative day and received aspirin and elastic stockings as their only thromboprophylaxis. The overall deep vein thrombosis rate was 41% (2% had proximal clots). The rate of deep vein thrombosis was not related to obesity, history of heart disease, hypertension, prior malignancy, smoking, diagnosis of osteoarthritis, duration of surgery, type of local anesthetic used, or the use of postoperative epidural analgesia. The rate of deep vein thrombosis varied significantly between surgeons: one surgeon had an overall deep vein thrombosis rate of 58% (proximal thrombi, 4%) whereas the other two surgeons had a deep vein thrombosis rate of 35% (proximal clot thrombi, 1%). A number of possible mechanisms to explain the variation in deep vein thrombosis rates between surgeons are provided.

Effect of hypotensive epidural anaesthesia on acetabular cement-bone fixation in total hip arthroplasty.

We selected 20 matched pairs of patients who had had total hip arthroplasty by the same surgeon using the same cemented technique. Matching was by age, sex, height, weight and diagnosis. One of each pair had received hypotensive epidural anaesthesia, with less than 300 ml blood loss: the other had normotensive general anaesthesia with more than 500 ml of blood loss. Early postoperative radiographs were evaluated independently by three blinded observers, using a scoring criteria which assessed the quality of the cement-bone interface. The results showed that patients who had received epidural anaesthesia had significantly better radiographic scores (p less than 0.02). Our findings suggest that hypotensive anaesthesia facilitates penetration of cement into bone.

Supraventricular tachyarrhythmias during total joint arthroplasty. Incidence and risk.

Perioperative supraventricular tachyarrhythmias (AF/SVT) have been long recognized as a complication after major surgery, but little is known about the incidence after major nonthoracic surgery. One thousand two hundred ten consecutive patients undergoing total hip or knee arthroplasty were studied to determine the incidence of new onset AF/SVT. Information on preoperative medical history and laboratory tests were collected in a subset of 583 patients, and analyzed using logistic regression and linear analysis to determine risk. Ninety-four-and-one-half percent of patients received an epidural anesthetic, 4.1% had general anesthesia and 1.3% had spinal anesthesia. New onset AF/SVT was found in 38 of 1210 patients, representing an incidence of 3.1%. In the subset of 583 patients, the incidence was 4.8%. The only variables found to be independently associated with the perioperative development of AF/SVT were a history of atrial fibrillation, increasing age, left anterior hemi-block, and atrial premature depolarizations on the preoperative electrocardiogram. In those patients 60 years of age or older with one or more positive risk factors (13% of the study population), the incidence was 18.2%. In those patients less than 60 years of age with none of the identified risks, the incidence was 1.9%.