Editorial III: Remembering awareness.
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Anesthesia↗
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Strict thermoregulation attenuates myocardial injury during coronary artery bypass graft surgery as reflected by reduced levels of cardiac-specific troponin I.
We assessed the cardioprotective effects of perioperative maintenance of normothermia by determining the perioperative profile of troponin I, a highly cardiac-specific protein important in risk stratification of patients with acute ischemic events. Candidates for their primary coronary artery bypass grafting (CABG) were randomized into a new thermoregulation system group, Allon( thermoregulation (AT; n = 30), and a routine thermal care (RTC; n = 30) group. Anesthetic and operative techniques were similar in both groups. Intraoperative warming was applied before and after cardiopulmonary bypass (CPB) and up to 4 h after surgery. Perioperative temperature and hemodynamic data were recorded. Blood samples for creatine kinase (CK) and its isoform, MB (CK-MB), and for cardiac-specific troponin I (cTnI) were obtained at predetermined intervals throughout the entire operation. Core and skin temperatures were higher in the AT group at all time points. The systemic vascular resistance was lower and the cardiac index higher in the AT group at all intra- and postoperative time points. Increases in CK, CK-MB, and cTnI levels indicated intraoperative ischemic insult in all patients. The respective CK levels for the AT and RTC groups were 53.3 +/- 22.7 IU/L and 47.9 +/- 17.86 IU/L at the time of anesthesia and 64.7 +/- 45.6 IU/L and 47.8 +/- 19.4 IU/L 30 min after the onset of surgery, demonstrating thereafter a steep increase before the discontinuation of CPB. CK-MB mass concentrations in both groups behaved almost identically. Pre-CPB cTnI levels at anesthesia induction were 0.3 +/- 0 ng/mL in both groups, followed by a distinctive profile observed after separation from CPB: 28.1 +/- 11.4 ng/mL, 26.05 +/- 9.20 ng/mL, and 22.3 +/- 8.9 ng/mL at discontinuation from CPB, chest closure, and 2 h after surgery, respectively, in the RTC group, versus 0.6 +/- 4.6 ng/mL, 6.6 +/- 5.5 ng/mL, and 7.9 +/- 4.76 ng/mL at these three time points, respectively, in the AT group (P < 0.01 between groups at the specified time points). Contrary to conventional thinking about the benefits of hypothermia, maintenance of normothermia throughout the non-CPB phases during CABG was demonstrated to be important in attenuating myocardial ischemic injury. Insofar as troponin I was more sensitive than other tested markers, it may provide important data on possible protection from myocardial insult and on other cardioprotective measures.
Aged↗
The Gulf war: anaesthetic experience at 32 Field Hospital Department of Anaesthesia and Resuscitation.
The organisation and the workload of the anaesthetic department of a Field Hospital deployed during the Gulf war were described. Suggestions are made as to how the problems encountered might be overcome in the future.
Anesthesia↗
Prolonged neuromuscular block from mivacurium in two patients with cholinesterase deficiency.
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Adult↗
The effect of hemispheric synchronization on intraoperative analgesia.
UNLABELLED: In this double-blinded randomized study, we sought to confirm that patients undergoing general anesthesia who were exposed to a hemispheric synchronization (Hemi-Sync) musical recording during surgery had a smaller analgesia requirement, as was suggested in a previous study. Bispectral index monitoring was used to adjust depth of hypnosis, and hemodynamic variables were used to determine analgesia administration. Consented patients underwent either laparoscopic bariatric or one-level lumbar disk surgery. After endotracheal intubation and application of headphones, baseline heart rate and arterial blood pressure were established. Isoflurane was titrated to maintain sedation on the basis of a target bispectral index range of 40-60, and 25-microg increments of fentanyl were administered in response to increases in heart rate and systolic arterial blood pressure. Bariatric patients who listened to Hemi-Sync required one-third less fentanyl than the control group (mean [SD]: 0.015 [0.01] vs 0.024 microg.kg(-1).min(-1) [0.01]) (P = 0.009). It is interesting to note that lumbar patients in the experimental and control groups required similar amounts of fentanyl (0.012 [0.01] vs 0.015 microg.kg(-1).min(-1) [0.01]). End-tidal isoflurane concentration was similar for Hemi-Sync and blank-tape patients (bariatric, 0.74% (0.14) vs 0.77% (0.21); lumbar, 0.36% [0.16] vs 0.39% [0.12]). The bariatric patients in this study demonstrated that Hemi-Sync may be an innovative intraoperative supplement to analgesia. IMPLICATIONS: The purpose of this study was to determine the decrease in analgesia requirement for patients listening to hemispheric synchronization (musical tones) while under general anesthesia. We demonstrated that bariatric patients who listened to hemispheric synchronization had a smaller analgesia requirement than those who listened to a blank tape.
Analgesia↗
Awareness under general anesthesia.
General anesthesia aims to eliminate patients' awareness of excruciating pain during surgery. Nevertheless, rare occurrences of patient awareness continue because the problem is not yet completely preventable. One study puts the incidence of awareness at 0.18% for patients receiving muscle relaxants and at 0.10% for patients not given relaxant drugs. Awareness experiences frighten patients and impact their implicit and explicit memories in ways that can leave a lifetime of residual emotional and psychological problems ranging from sleep disturbances, nightmares, and daytime anxiety that may subside with time to development of post-traumatic stress disorder. Most anesthetists monitor depth of anesthesia by assessing intraoperative hemodynamic responses to surgical stimuli--an approach questioned by some authors. Several depth-of-anesthesia monitors are available, but there is no ideal monitor that is 100% reliable. This review provides an overview of literature that reports findings associated with the monitoring and occurrence of intraoperative awareness. These studies indicate assessment methods that can be trusted when we provide general anesthesia and what measures can be taken to prevent recall by patients under general anesthesia.
Anesthesia, General↗
Hemodynamic effect of propofol in enalapril-treated hypertensive patients during induction of general anesthesia.
Angiotensin converting enzyme inhibitor (ACE-I) treated hypertensive patients are well known to be at risk during general anesthesia, because of hypotension that can occur. We compared hemodynamic changes in these patients during induction of general anesthesia with propofol and etomidate - two intravenous anesthetics. Hypotension after propofol that we observed in ACE-I group versus normotension after etomidate (p < 0.001) in our opinion may be the result of additive effect of similar endothelium-dependent mechanism of action of propofol and ACE-I, i.e. increase in production and release of nitric oxide (NO). This very unique observation, however, needs further investigation to precisely define the mechanism of our finding.
Anesthesia, General↗
[Respiratory risk of general surgery in adults].
Disorders of ventilation and postoperative bronchial and pulmonary infections still create serious problems in general surgery. Three factors determine these complications: (1) the transient and usually resolutive repercussions of anaesthesia on ventilation; (2) the sometimes deep and prolonged alteration of lung function directly due to the surgical procedure, and (3) the patient's underlying condition. In practice, this last group of surgical patients can be divided into fragile subjects (elderly people, pregnant women), subjects at risk (smokers, malnourished or obese patients) and disabled subjects suffering from chronic obstructive or restrictive lung disease, asthma or heart disease. Preoperative clinical, radiological and, chiefly, functional evaluation leads to preventive measures. Preparation for surgery relies, to a great extent, on respiratory physiotherapy which, if needed, may be integrated in a pneumological therapeutic program. Combined with an efficient postoperative analgesia and with an optional anaesthesia technique, respiratory physiotherapy is essential to the prevention of respiratory complications in surgery.
Adult↗
Corneal epithelial healing after penetrating keratoplasty using topical Healon versus balanced salt solution.
The authors conducted a prospective study of 38 consecutive corneal transplant patients over a five-and-one-half month period in order to evaluate the effect of intraoperative hydration with topical Healon versus balanced salt solution on postoperative epithelial healing in the corneal graft. Eight independent variables, including patient age, sex, operating room time, donor age, donor time in McCarey-Kaufman media, intraoperative hydration with balanced salt solution versus Healon, and the amount of postoperative punctate epithelial keratitis measured on postoperative day 1, day 2, and at one week were compared using a multiple linear regression method. While the correlation between donor age (p = .060) and patient age (p = .088) with the amount of punctate epithelial keratitis at one week post graft approached statistical significance, only the Healon-treated group showed a high correlation to more complete graft healing one week postoperatively (p = 0.002). Topical Healon during keratoplasty may foster epithelial healing, but it also may present technical challenges of which the surgeon should be aware.
Adult↗
Validity and reliability of spinal cord monitoring in neuromuscular spinal deformity surgery.
Somatosensory evoked potentials (SSEPs) have become a standard of care in surgery for spinal deformity. Recent reports in the literature have suggested SSEP monitoring is not efficacious in surgeries for patients with neuromuscular disease. Electrophysiologic data were retrospectively analyzed from 74 patients with various neuromuscular disorders undergoing spinal-deformity surgery from 1989 through February 1995 at this medical center. The monitoring protocol included SSEPs recorded from multiple sites located cortically, subcortically, and peripherally. Neurogenic motor evoked potentials (NMEPs) were also employed. Anesthetic regimens were controlled for compatibility with evoked potential monitoring. Use of this intraoperative monitoring protocol resulted in reliable data for 95% of the patient population having baseline responses. Findings suggest that evoked potentials can be used effectively during surgery for neuromuscular spinal deformity. Use of a specific protocol allowed acquisition of reliable data intraoperatively, suggesting these methods are a valid means of monitoring neurologic status.
Adolescent↗
Potassium in the perioperative period.
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Humans↗
Intraoperative radiation enhances decline of pancreatic exocrine function after pancreatic head resection.
Intraoperative radiation therapy has been introduced to improve survival rates after resection of biliopancreatic cancer. Early and late effects of intraoperative radiation on the exocrine and endocrine functions of the residual pancreas were examined in 54 patients with pancreatic head resection. Of the 54 patients, 20 underwent intraoperative radiation (A group) and the other 34 did not (B group). Fasting blood sugar level, a 120-min value of the 75-g oral glucose tolerance test, N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and amount of postoperative pancreatic juice drainage were compared between groups A and B at preoperative and early and late postoperative times. Fasting blood sugar level and a 120-min value of the 75-g oral glucose tolerance test (OGTT) showed no change at the early (<2 months) postoperative period of the two groups. At the late (>6 months) postoperative period, fasting blood sugar showed no alteration, while the 75-g OGTT 120-min value increased compared to the preoperative level in both groups. In the group A, the 75-g OGTT 120-min value at the late postoperative period was significantly higher than those at the preoperative and early postoperative periods (289.4 +/- 104.9 vs 193.0 +/- 58.2 mg/dl, P = 0.0198 and 289.4 +/- 104.9 vs 184.4 +/- 104.9 mg/dl, P = 0.0285). Preoperative BT-PABA excretion value was not different between the two groups. It decreased at the early postoperative period and returned to the preoperative level at the late postoperative period in both the groups. The decline of BT-PABA in group A was 23 +/- 21%, which was significantly larger than 11 +/- 24% in group B. The total amount of postoperative pancreatic juice drainage from postoperative days (POD) 4-13 in group A was about half as much as that in group B (720.8 +/- 916.4 vs 1433.8 +/- 962.1 ml, P = 0.0128). Univariate and multivariate regression analysis of factors concerning the decline of BT-PABA values at the early postoperative period showed that intraoperative radiation was a significant independent determinant. In conclusion, these results suggest that intraoperative radiation causes significant deterioration of pancreatic exocrine function at the early postoperative period. Intraoperative radiation for resectable periampullary carcinoma should be reappraised based on the decline of the pancreatic exocrine function as well as the improvement of the survival curve.
4-Aminobenzoic Acid↗
Does perioperative tactile evaluation of the train-of-four response influence the frequency of postoperative residual neuromuscular blockade?
The authors conducted a randomized controlled clinical trial to evaluate the usefulness of perioperative manual evaluation of the response to train-of-four (TOF) nerve stimulation. A total of 80 patients were divided into four groups of 20 each. For two groups (one given vecuronium and one pancuronium), the anesthetists assessed the degree of neuromuscular blockade during operation and during recovery from neuromuscular blockade by manual evaluation of the response to TOF nerve stimulation. In the other two groups, one of which received vecuronium and the other pancuronium, the anesthetists evaluated the degree of neuromuscular blockade solely by clinical criteria. The use of a nerve stimulator was found to have no effect on the dose of relaxant given during anesthesia, on the need for supplementary doses of anticholinesterase in the recovery room, on the time from end of surgery to end of anesthesia, or on the incidence of postoperative residual neuromuscular blockade evaluated clinically. The median (and range of) TOF ratios recorded in the recovery room were 0.75 (0.33-0.96) and 0.79 (0.10-0.97) in the vecuronium groups monitored with and without a nerve stimulator, respectively. These ratios were significantly higher than those found in the pancuronium groups, which wre 0.66 (0.06-0.90) and 0.63 (0.29-0.95), respectively. However, no difference was found between the vecuronium and pancuronium groups in the number of patients showing clinical signs of residual neuromuscular blockade, as evaluated by the 5-s head-lift test.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
[Evaluation of 3757 cases of open biliary tract surgery before the introduction of the laparoscopic method (basis for comparison)].
3757 elective nonmalignant biliary tract operations are evaluated retrospectively in the 17-year period from January 1, 1974 to December 31, 1990. The operations were divided into four periods according to development and frequency of intraoperative diagnostics: I. period without examinations of common bile duct (511 operations), II. selective period (848 operations), III. routine period (906 operations), IV. restricted routine period (1492 operations). The authors experienced improvement in their results if they carried out intravenous cholangiography routinely. Comparing eight characteristic factors they believe that their results are favourable if they performed intraoperative common bile duct examinations (manometry, cholangiography, flow rate measurement) in 39.6% rate and if they employed praeoperatively EST if necessary. They propose the selective intraoperative cholangiography. In the period of 39.6% intraoperative cholangiography (restricted routine period) they found common bile duct stones in 10.7%, unsuspected stones in 0.4%, retained stones in 1.6%, unnecessary choledochotomies in 2.7% and intraoperative common bile duct injuries in 0.2%. The overall mortality rate was 0.4%. They deal with the intraoperative differential diagnostics of Vater papilla stenosis and spasm.
Ampulla of Vater↗
Potassium in the perioperative period.
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Anesthesia↗
[Perioperative melatonin secretion rhyme in patients undergoing coronary artery bypass grafting surgery].
OBJECTIVE: To investigate perioperative patterns of melatonin and cortisol secretion rhyme in patients undergoing coronary artery bypass grafting surgery. METHODS: Eleven male patients scheduled for elective coronary artery bypass grafting surgery (CABG) under hypothermic cardiopulmonary bypass (CPB) were enrolled in the study. Anesthesia was induced and maintained with propofol (3 mg.kg-1.h-1) and supplemented with fentanyl (15 micrograms/kg). Blood samples were taken during surgery at specific time-points and every 3 h in the immediate postoperative period and postoperative day 2 and day 3. Plasma melatonin and cortisol levels were measured by radioimmunoassay and enzyme-linked immunosorbent assay respectively. RESULTS: During surgery, plasma melatonin levels were below the minimum sensitivity level but low levels, without circadian variation, were measured during the immediate postoperative period. During postoperative day 2 and day 3, circadian secretion patterns of melatonin were present in 10 patients and showed an inverse correlation with light intensity exposed (r = -0.480, P = 0.01). Plasma cortisol levels in the immediate postoperative period were significantly higher than those before induction of anesthesia (P < 0.01). During postoperative day 2 and day 3, only 3 patients regained circadian secretion of cortisol. CONCLUSIONS: It is concluded that melatonin and cortisol secretion are disrupted during cardiac surgery and in the immediate postoperative period.
Cardiopulmonary Bypass↗
Potential role for intraoperative gamma probe identification of normal parathyroid glands.
BACKGROUND: Patients undergoing central neck surgery are at risk for hypoparathyroidism. We hypothesized that gamma probe identification of sestamibi-labeled parathyroid glands might help maximize parathyroid preservation. METHODS: Records of 351 patients who underwent central neck surgery were reviewed. A subgroup of patients underwent sestamibi injection followed by gamma probe-directed parathyroid gland identification. RESULTS: Operation was performed for malignancy in 73% of patients and represented a reoperation in 34%. Persistent hypoparathyroidism was more common in patients who underwent reoperation versus a primary operation (6.8% versus 1.7%; P = 0.02). Thirteen patients underwent gamma probe-directed identification of sestamibi-labeled parathyroid glands; in 6 of these patients, sestamibi-labeled parathyroid glands were salvaged from the resected specimens and autografted. None of these 13 patients developed persistent hypoparathyroidism. CONCLUSIONS: Patients undergoing reoperative central neck surgery are at increased risk for postoperative hypoparathyroidism. Gamma probe-directed salvage of sestamibi-labeled parathyroid glands may help maximize parathyroid preservation, especially in complex or reoperative central neck surgery.
Gamma Cameras↗
Change in right ventricular function during off-pump coronary artery bypass graft surgery.
OBJECTIVES: Hemodynamic derangement during displacement of beating heart in off-pump coronary artery bypass graft (OPCAB) surgery might be related with right ventricular (RV) dysfunction. We evaluated RV function and hemodynamic alterations using a thermodilution pulmonary artery catheter. METHODS: The study included 30 patients undergoing OPCAB, using single pericardial suture and tissue stabilizer. A thermodilution pulmonary artery catheter for continuous monitoring of the cardiac output (CO), right ventricular ejection fraction (RVEF) and RV volume was inserted before anesthesia. The hemodynamic variables were measured after the induction of anesthesia, 5 min after the heart was positioned for each coronary anastomosis and after the sternum was closed. RESULTS: There was no significant change in the RVEF and cardiac index during anastomosis of the left anterior descending artery and right coronary artery. However, the significantly reduced RVEF accompanied by an increase in RV afterload and decrease in the CO was observed during anastomosis of the obtuse marginal (OM) artery. RV volumes did not significantly change during anastomoses, though the right atrial pressure increased during anastomoses of all coronary arteries. CONCLUSIONS: The displacement of beating heart for positioning during anastomosis of the graft to OM artery caused significant derangement of RV function and decrease in CO. A thermodilution catheter continuously measuring the CO and RVEF was useful to monitor the change in RV function and volume during OPCAB.
Aged↗