Gilles Boccara

Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery.

Background Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient. Methods Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores. Results Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24%vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups. Conclusion After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.

Incidence, risk factors, and prognosis of a moderate increase in plasma creatinine early after cardiac surgery.

Objective To evaluate the incidence and prognosis of a moderate increase in serum creatinine early after cardiac surgery. Design Retrospective clinical study. Setting Surgical intensive care unit in a university hospital. Patients Five hundred and ninety-one consecutive adult patients operated on for cardiac surgery during 1 year. Interventions Plasma creatinine was measured systematically before and during the first 3 days after surgery. Comorbid events were assessed as organ dysfunction (cardiac, pulmonary, hematologic, and neurologic), allowing us to calculate for each patient a dysfunction score (0–5). Measurements and Main Results Postoperative plasma creatinine increased by ≥20% in 15.6% of patients; eight of these required dialysis. A 20% increase in plasma creatinine was associated with other organ dysfunction in 79.3% of patients. Overall mortality rate was 2.7% and increased with the dysfunction score (17.7% for a dysfunction score ≥3). Mortality rate was 12.0% for patients who had 20% increased plasma creatinine with other organ dysfunction but was 0% for patients without other organ dysfunction. A logistic regression analysis revealed that the most important prognostic factors of death were cardiac dysfunction (odds ratio, 8.5; 95% confidence interval, 2.2–32.5) and the association of renal dysfunction and hematologic dysfunction (odds ratio = 12.0; 95% confidence interval, 3.9–37.2). Mean intensive care unit stay of patients with increased plasma creatinine was significantly longer (8.1 ± 5.6 vs. 4.3 ± 1.4 days, p < .01) and increased significantly with the dysfunction score (p < .01). Patients with isolated increased plasma creatinine had a significantly longer stay in the intensive care unit than patients without any organ dysfunction (4.6 ± 1.4 vs. 3.9 ± 0.9, p < .01). Conclusion Our results suggest that a postoperative 20% increase in plasma creatinine after cardiac surgery is not rare and has a significant impact on postoperative outcome, mainly when multiple organ dysfunction occurs. Any preoperative reduced renal reserve or perioperative renal ischemia increases the renal risk.

The relationship among carbon dioxide pneumoperitoneum, vasopressin release, and hemodynamic changes

UNLABELLED We assessed the role of vasopressin (VP) for the hemodynamic response to pneumoperitoneum in pigs. Four groups of anesthetized pigs were investigated. Nine pigs were intraabdominally insufflated with CO2 and eight were intraabdominally insufflated with argon; eight pigs received an i.v. injection of 1 mg/kg SR 49059, a VP antagonist, before CO2 insufflation; and six pigs received SR 49059 alone. Hemodynamics, plasma concentrations of VP and vasoactive hormones, and Paco2 were measured. Data were analyzed by using analysis of variance, Students t-test, and Mann-Whitney U-test. Five minutes after insufflation, changes in systemic vascular resistance (SVR) were significantly correlated with changes in VP (r = 0.72; P = 0.005) but not with changes in epinephrine, norepinephrine, renin activity, or Paco2. SVR increased during CO2 insufflation but not during argon insufflation or CO2 insufflation with a preceding infusion of SR 49059. The SR 49059 injection itself resulted in increases in heart rate and cardiac output and decreases in blood pressure and SVR. We conclude that, during CO2 pneumoperitoneum in pigs, absorbed CO2 initiates a pathophysiological process that stimulates VP release. Hence, VP most likely plays a key role in the hemodynamic response to a CO2-induced pneumoperitoneum. IMPLICATIONS Intraabdominal insufflation of CO2 is associated with hemodynamic and hormonal changes. Investigating CO2 and argon-insufflated pigs and using a vasopressin antagonist, we found that CO2 insufflation released vasopressin, which, in turn, induced hemodynamic perturbances.

Terlipressin versus norepinephrine to correct refractory arterial hypotension after general anesthesia in patients chronically treated with renin-angiotensin system inhibitors

Background Terlipressin, a precursor that is metabolized to lysine-vasopressin, has been proposed as a drug for treatment of intraoperative arterial hypotension refractory to ephedrine in patients who have received long-term treatment with renin-angiotensin system inhibitors. The authors compared the effectiveness of terlipressin and norepinephrine to correct hypotension in these patients. Methods Among 42 patients scheduled for elective carotid endarterectomy, 20 had arterial hypotension following general anesthesia that was refractory to ephedrine. These patients were the basis of the study. After randomization, they received either 1 mg intravenous terlipressin (n = 10) or norepinephrine infusion (n = 10). Beat-by-beat recordings of systolic arterial blood pressure and heart rate were stored on a computer. The intraoperative maximum and minimum values of blood pressure and heart rate, and the time spent with systolic arterial blood pressure below 90 mmHg and above 160 mmHg, were used as indices of hemodynamic stability. Data are expressed as median (95% confidence interval). Results Terlipressin and norepinephrine corrected arterial hypotension in all cases. However, time spent with systolic arterial blood pressure below 90 mmHg was less in the terlipressin group (0 s [0–120 s]vs. 510 s [120–1011 s];P < 0.001). Nonresponse to treatment (defined as three boluses of terlipressin or three changes in norepinephrine infusion) occurred in zero and eight cases (P < 0.05), respectively. Conclusions In patients who received long-term treatment with renin-angiotensin system inhibitors, intraoperative refractory arterial hypotension was corrected with both terlipressin and norepinephrine. However, terlipressin was more rapidly effective for maintaining normal systolic arterial blood pressure during general anesthesia.

Brachial plexus nerve block exhibits prolonged duration in the elderly.

Background Upper limb trauma occurs frequently in elderly patients for whom peripheral nerve blocks are often preferred for anesthesia. The characteristics of such regional blocks have, however, never been described in an elderly population. Therefore, the authors assessed prospectively the onset and duration of upper extremity peripheral nerve block (the mid-humeral block) in elderly and young patients undergoing emergency upper extremity surgery. Methods Consecutive patients aged > 70 yr or < 70 yr received a mid-humeral block with a small volume of ropivacaine, 0.75%. Five milliliters was injected onto each of the musculocutaneous, radial, ulnar, and median nerves. Time to complete sensory and motor block and durations of complete sensory and motor block were assessed. Results are shown as median and its 95% confidence interval. Results Median ages were 77 yr (95% CI, 72–81 yr) and 39 yr (95% CI, 27–46 yr) in the two groups. Both groups had similar times to complete sensory blockade. The elderly group had longer durations of complete sensory (390 min [range, 280–435 min]vs. 150 min [range, 105–160 min];P < 0.05) and motor (357 min [range, 270–475 min]vs. 150 min [range, 90–210 min];P < 0.05) blockade. Duration of complete sensory block was significantly correlated with age (&rgr; = 0.56;P < 0.05). Conclusions Age is a major determinant of duration of complete motor and sensory blockade with peripheral nerve block, perhaps reflecting increased sensitivity to conduction failure from local anesthetic agents in peripheral nerves in the elderly population.

Argon Pneumoperitoneum Is More Dangerous than CO2 Pneumoperitoneum During Venous Gas Embolism

We investigated the possibility of using argon, an inert gas, as a replacement for carbon dioxide (CO2).The tolerance of argon pneumoperitoneum was compared with that of CO2 pneumoperitoneum. Twenty pigs were anesthetized with enflurane 1.5%. Argon (n = 11) or CO2 (n = 9) pneumoperitoneum was created at 15 mm Hg over 20 min, and serial intravenous injections of each gas (ranging from 0.1 to 20 mL/kg) were made. Cardiorespiratory variables were measured. Transesophageal Doppler and capnographic monitoring were assessed in the detection of embolism. During argon pneumoperitoneum, there was no significant change from baseline in arterial pressure and pulmonary excretion of CO2, mean systemic arterial pressure (MAP), mean pulmonary artery pressure (PAP), or systemic and pulmonary vascular resistances, whereas CO2 pneumoperitoneum significantly increased these values (P < 0.05). During the embolic trial and from gas volumes of 2 and 0.2 mL/kg, the decrease in MAP and the increase in PAP were significantly higher with argon than with CO2 (P < 0.05). In contrast to CO2, argon pneumoperitoneum was not associated with significant changes in cardiorespiratory functions. However, argon embolism seems to be more deleterious than CO2 embolism. The possibility of using argon pneumoperitoneum during laparoscopy remains uncertain. Implications: Laparoscopic surgery requires insufflation of gas into the peritoneal cavity. We compared the hemodynamic effects of argon, an inert gas, and carbon dioxide in a pig model of laparoscopic surgery. We conclude that argon carries a high risk factor in the case of an accidental gas embolism. (Anesth Analg 1997;85:1367-71)

Comparative Cardiac Effects of Terlipressin, Vasopressin, and Norepinephrine on an Isolated Perfused Rabbit Heart

Background: Terlipressin, a synthetic analog of arginine-vasopressin (AVP), has been proposed as an effective vasopressive therapy in catecholamine-resistant vasodilatory shock. Although beneficial effects of terlipressin on systemic arterial pressure have been clearly demonstrated, its intrinsic effects on coronary circulation and myocardial performances remain unknown. Methods: The authors compared the coronary and myocardial effects of terlipressin (1–100 nm, n = 10), AVP (10–1000 pm, n = 10), and norepinephrine (1–100 nm, n = 10) on an erythrocyte-perfused isolated rabbit heart. The cardiac effects of terlipressin were also assessed in erythrocyte-perfused hearts in which the myocardial oxygen delivery was maintained constant and buffer-perfused hearts. Finally, the cardiac effects of terlipressin and AVP were studied in hearts pretreated by [d(CH2)5Tyr(Me)]AVP (0.1 &mgr;m), a selective V1a receptor antagonist. Results: Norepinephrine induced a biphasic coronary effect associated with a concentration-dependent increase in myocardial performances. AVP and terlipressin significantly decreased coronary blood flow and impaired myocardial performances from 30 pm and 30 nm, respectively (P < 0.05). The cardiac side-effects of terlipressin were confirmed in buffer-perfused hearts but the maintenance of a constant myocardial oxygen delivery constant abolished its effects on myocardial performances. The cardiac effects induced by terlipressin and AVP were nearly completely abolished on hearts pretreated by [d(CH2)5Tyr(Me)]AVP. Conclusions: On isolated rabbit heart, terlipressin induced a coronary vasopressor effect and in turn myocardial depression only at supratherapeutic concentrations (≥30 nm). Its effects are mainly mediated via V1a receptors. However, these potential negative side effects on the heart were less pronounced than were those of AVP.

Patient-controlled epidural analgesia after abdominal surgery: Ropivacaine versus bupivacaine

In this randomized, double-blinded study we sought to assess the analgesic efficacy of ropivacaine and bupivacaine in combination with sufentanil and the efficacy of ropivacaine alone after major abdominal surgery. Sixty patients undergoing major abdominal surgery received standardized general anesthesia combined with epidural thoracic analgesia. They were allocated to one of three groups: the BS group received postoperative patient-controlled epidural analgesia with 0.125% bupivacaine plus 0.5 &mgr;g/mL sufentanil; the RS group received 0.125% ropivacaine plus 0.5 &mgr;g/mL sufentanil; and the R group received 0.2% ropivacaine, with the patient-controlled epidural analgesia device set at bolus 2–3 mL and background infusion 3–5 mL/h. Visual analog scale scores were significantly lower during coughing in the BS group compared with the RS and R groups and in the RS group compared with the R group. The BS group required significantly less local anesthetic (milligrams per day) during the first three postoperative days compared with the RS and R groups, and the RS group, significantly less than the R group. No major side effects were noted in any group. We conclude that, after major abdominal surgery, thoracic epidural analgesia was more effective with bupivacaine than with ropivacaine when these two local anesthetics are used in a mixture with sufentanil. Ropivacaine alone was less effective than ropivacaine in combination with sufentanil.

Terlipressin for treating intraoperative hypotension: can it unmask myocardial ischemia?

IMPLICATIONS After administration of terlipressin to treat hypotension related to induction of general anesthesia, profound hypertension occurred in association with myocardial ischemia and occlusion of the left anterior descending coronary artery. The authors emphasize cautious use of this drug because of such adverse events.

Remifentanil induces systemic arterial vasodilation in humans with a total artificial heart

BackgroundTo assess intrinsic vascular effects of remifentanil, increased concentrations were infused in critically ill patients with a total artificial heart. MethodsIn the early postoperative period after implantation of a total artificial heart, nine ventilated patients requiring short general anesthesia were included in this study. After anesthesia was induced with 0.3 mg/kg intravenous etomidate, the artificial heart settings were modified to render cardiac output “preload-independent.” While maintenance of anesthesia was ensured by a continuous infusion of etomidate, increased concentrations of remifentanil (from 0.1 to 1 &mgr;g · kg−1 · min−1) were infused in steps of 5 min under hemodynamic monitoring, including left and right atrial pressures, systemic and pulmonary arterial pressures, and left and right cardiac indices. The invasive procedure was started under the highest concentration of remifentanil tolerated by the patient. Infusion of remifentanil was stopped at the end of the invasive procedure, while etomidate infusion was maintained. New hemodynamic measurements were performed at the end of the 12-min recovery period. ResultsRemifentanil produced a dose-dependent and significant decrease in systemic arterial pressure and vascular resistances (n = 9) from a concentration of 0.25 &mgr;g · kg−1 · min−1. No significant changes were observed on pulmonary vascular resistances (n = 6). Neither right (n = 9) nor left (n = 6) atrial pressures were affected by remifentanil infusion. Hemodynamic variables returned to baseline value over the 12-min recovery period. ConclusionsIn humans with a total artificial heart, remifentanil induces a systemic arterial vasodilation without significant effect on the capacitance vessels.