Incidence Of Intraoperative Hypotension Research Articles

A Comparison of Single-Dose Caudal Clonidine, Morphine, or Hydromorphone Combined with Ropivacaine in Pediatric Patients Undergoing Ureteral Reimplantation

Caudal blockade is a common technique for pediatric postoperative analgesia. While safe and effective, caudal opioids are associated with troublesome side effects. Caudal clonidine may offer significant analgesic benefits. We prospectively compared the analgesic, side effect, and rehabilitation profiles of caudal clonidine, hydromorphone, or morphine in a group of 60 pediatric patients undergoing ureteral reimplantation. Patients aged 6 mo to 6 yr were evenly and randomly enrolled in a double-blind manner. Patients received a single caudal dose of 2 mcg/kg of clonidine, 10 mcg/kg of hydromorphone, or 50 mcg/kg of morphine, combined with 1.0 mL/kg of 0.2% ropivacaine with epinephrine. After sevoflurane in oxygen/air anesthesia, all subjects received proxy nurse-controlled analgesia with morphine. Postoperative pain intensity, use of IV morphine, and side effects were assessed during the first 24 h. Oral intake and discharge home were recorded. Caudal clonidine resulted in less postoperative nausea and vomiting (P = 0.01) and pruritus (P = 0.007) than did caudal hydromorphone or caudal morphine. Caudal morphine produced more sustained initial analgesia than did caudal clonidine (P = 0.02). No difference was observed in pain scores, total morphine use, time to first oral intake or discharge home. No postoperative respiratory depression, excessive sedation, hypotension, or bradycardia was identified. Although caudal morphine may result in more sustained initial analgesia, caudal clonidine combined with nurse-controlled analgesia appears to provide comparable analgesia with fewer side effects. Based on these results, the use of caudal clonidine may be superior to caudal opioids after pediatric ureteral reimplantation.

Predictors of Immediate Tracheal Extubation in the Operating Room After Liver Transplantation

Immediate postoperative extubation may reduce the incidence of postoperative respiratory complications after orthotopic liver transplantation (OLT). We evaluated the predictors of immediate tracheal extubation in the operating room (OR) in our patients by retrospectively reviewing data from all patients who underwent OLT between January 2004 and June 2006. The patients were divided into two groups according to whether they had undergone extubation in the OR (group 1 n = 52) or in the intensive care unit (ICU; group 2 n = 48). When compared with the patients in group 2, those in group 1 had lower mean preoperative serum creatinine levels (0.9 ± 1 vs 0.6 ± 0.3 mg/dL, P = .04) and intraoperative transfusion requirements (packed red blood cells, 35.5 ± 29.8 vs 25.6 ± 19.0 mL/kg; P = .05, and fresh frozen plasma, 33.1 ± 15.6 vs 25.7 ± 14.3 mL/kg; P = .01). The incidence of intraoperative hypotension and emergent OLT was significantly greater in group 2 than group 1 (33.3% vs 13.5%, P = .01 and 45.8% vs 21.2%, respectively, P = .009). On logistic regression analysis, only emergent OLT ( P = .009, odds ratio = 3.5) and intraoperative hypotension ( P = .018, odds ratio = 3.7) were significantly associated with a lower probability of immediate postoperative extubation in the OR. Our results suggested that hemodynamic stability and elective OLT were predictors of successful immediate tracheal extubation in the OR.

The Prophylactic Granisetron Does Not Prevent Postdelivery Nausea and Vomiting During Elective Cesarean Delivery Under Spinal Anesthesia

Intraoperative nausea and vomiting (IONV) during cesarean delivery (CD) under regional anesthesia has multiple etiologies, and the role of prophylactic antiemetics for prevention of IONV remains controversial. In this trial we sought to determine the efficacy of granisetron for prevention of IONV during elective CD under spinal anesthesia with strict control of the causative factors. The study was conducted as a randomized, double-blind, placebo-controlled trial in 176 parturients. After administration of 10 mL/kg of lactated Ringer's solution, spinal anesthesia was administered with 0.75% hyperbaric bupivacaine 15 mg, fentanyl 10 microg, and morphine 100 microg. Systolic blood pressure was maintained at 100% of baseline with aliquots of phenylephrine. Oxytocin 0.5 IU was administered IV upon delivery followed by a maintenance infusion. The patients received either granisetron 1 mg or normal saline IV immediately after cord clamping. In case of persistent IONV, rescue dimenhydrinate 50 mg IV was administered. The primary outcome was the presence of postdelivery IONV. Secondary outcomes included the need for rescue antiemetic, hypotension, pain, and adverse effects. The incidence of postdelivery IONV was 20.4% in the granisetron group and 17.0% in the control group (P = 0.56, NS). The incidence of intraoperative hypotension, pre- (9.6%) and postdelivery (6.2%), was similar in both groups. The incidence of postdelivery pain (2.2% vs 4.5%, P = 0.68) and the requirement for rescue antiemetic (8% vs 6.8%, P = 0.77) were similar in the granisetron and control groups. Despite strict control of the causative factors, IONV still affects 18% of patients undergoing elective CD, and prophylactic granisetron 1 mg is ineffective under the studied circumstances.

Remifentanil Update

The anilidopiperidine opioid remifentanil has pharmacodynamic properties similar to all opioids; however, its pharmacokinetic characteristics are unique. Favourable pharmacokinetic properties, minimally altered by extremes of age or renal or hepatic dysfunction, enable easy titration and rapid dissipation of clinical effect of this agent, even after prolonged infusion. Remifentanil is metabolised by esterases that are widespread throughout the plasma, red blood cells, and interstitial tissues, whereas other anilidopiperidine opioids (e.g. fentanyl, alfentanil and sufentanil) depend upon hepatic biotransformation and renal excretion for elimination. Consequently, remifentanil is cleared considerably more rapidly than other anilidopiperidine opioids. In addition, its pKa (the pH at which the drug is 50% ionised) is less than physiological pH; thus, remifentanil circulates primarily in the non-ionised moiety, which quickly penetrates the lipid blood-brain barrier and rapidly equilibrates across the plasma/effect site interface. By virtue of these distinctive pharmacokinetic properties, the context-sensitive half-time (i.e. the time required for the drug's plasma concentration to decrease by 50% after cessation of an infusion) of remifentanil remains consistently short (3.2 minutes), even following an infusion of long duration (> or =8 hours). Remifentanil, a clinically versatile opioid, is useful for intravenous analgesia and sedation in spontaneously breathing patients undergoing painful procedures. Profound analgesia may be achieved with minimal effect on cognitive function. Remifentanil may also provide sedation and analgesia during placement of regional anaesthetic blocks, and in conjunction with topical anaesthesia and airway nerve blocks, it may be useful for blunting reflex responses and facilitating 'awake' fibreoptic intubation. Compared with fentanyl and alfentanil in a day-surgery setting, remifentanil supplementation of general anaesthesia may improve intraoperative haemodynamic control. Both emergence time and the incidence of respiratory depression during post-anaesthetic recovery may be reduced. However, outcomes such as home discharge time, post-emergence adverse effect profile, and patient and provider satisfaction are not significantly improved, and the incidence of intraoperative hypotension and bradycardia is greater. In addition, drug acquisition costs for remifentanil are higher and clinicians may need extra time to familiarise themselves with the drug's unique pharmacokinetics.Ironically, the quick dissipation of opioid analgesic effect following remifentanil discontinuation may be a significant clinical disadvantage. Unless little or no postoperative pain is anticipated, the clinician may wish to treat prospectively using local or regional anaesthesia, non-opioid analgesics, or longer-acting opioid analgesics.

Relationship between cardiac troponin I (cTnI) release during cardiac operations and myocardial cell death

The awareness of the diagnostic difficulty and the documented high mortality risk of perioperative myocardial infarction (PMI) has led to the wide use of work up to rule out PMI after major noncardiac operations. This has caused stable postoperative patients to be kept in monitored hospital beds for extended periods of time and to be subjected to additional tests. We hypothesized that the mortality of PMI is high and, therefore, the wide use of postoperative work up to identify these patients is justifiable. We performed the following study to prove our hypothesis. All patients in the recovery room after major noncardiac operations who underwent work up to rule out PMI were identified and followed. The PMI work up included care in an electronically monitored unit, physical assessment, continuous ECG monitoring, and three 12lead electrocardiograms and cardiac enzymes obtained at six to eight hour intervals. Data collection included patient demographics; preoperative cardiac risk factors; incidence of intraoperative hypotension, hemorrhage and ECG changes; type of anesthesia and operative procedures and their durations; postoperative ECG and cardiac enzyme results; the incidence of PMI and patient outcome. Two hundred patients were studied; 85 males and 115 females. Their mean age was 62.9 years. Preexisting conditions included hypertension in 162 patients, peripheral arterial disease in 102, diabetes mellitus in 97, angina in 30, previous myocardial infarction in 41, and smoking in 107. Of 200 patients, 164 had an abnormal preoperative ECG. Vascular operations were performed in 104 patients, nonvascular abdominal operations in 48, and other operations in the remaining 48. Intraoperatively, hypotension occurred in 29 patients, blood loss of >500 ml in 25 and ECG changes in 10. There were no deaths. PMI occurred in 5/200 (2.5%) patients. Four had undergone vascular operations and one had had an abdominal operation. The mean age of the patients with PMI was 64.2 years. The duration of operation and blood loss were similar to those of patients without PMI. None of these patients developed cardiac failure or cardiogenic shock and none of them died.