Ablation of liver metastasis: is preoperative imaging sufficiently accurate?

The recent introduction of cryotherapy and radiofrequency ablation of liver metastasis has expanded the indications for treatment. As technology has advanced, a percutaneous approach has been developed. Percutaneous treatment, however, requires accurate preoperative imaging. From 1993 to 1999, 179 patients underwent operative exploration for treatment of suspected hepatic metastases from colorectal carcinoma. One hundred seventy-seven patients were staged by preoperative CT, two patients were staged by MRI, and complete data were available in 176. Hepatic tumor count by preoperative imaging was compared to intraoperative tumor count obtained by inspection, palpation, ultrasonographic examination using a 3.5/7.5 MHz T probe, and careful gross sectioning of the resected specimen. Post hoc analysis was performed on 35 CT scans by two radiologists who specialize in abdominal CT. These radiologists were blinded to the intraoperative findings. Their interpretations were compared to the intraoperative counts and to each other. Thirty-four (19%) of 179 patients were deemed untreatable at operation because of unsuspected overwhelming liver involvement in 11 (6%) or extrahepatic metastases in 23 (13%). For the group, CT was accurate in 80 patients (45%), showed more lesions than were found in 16 (9%), and showed fewer metastases than were found in 80 (45%). When the preoperative scan predicted a solitary metastasis, it was correct in 45 (65%) of 69 patients and underestimated disease in 24 (35%). In the post hoc analysis, the mean numbers of lesions reported by the two radiologists did not differ from the mean number of tumors found; however, the radiologists' counts agreed on 16 (59%) and disagreed on 11 (41%) of the scans. The accuracy of CT decreased with increasing numbers of lesions. Regardless of the type of preoperative imaging, intraoperative findings altered the course of the operation in 96 (55%) of 176 patients. Preoperative imaging is not sufficiently accurate to permit adequate percutaneous treatment of hepatic metastases from colorectal carcinoma.

Intraoperative monitoring in neuroanesthesia: a national comparison between two surveys in Germany in 1991 and 1997. Scientific Neuroanesthesia Research Group of the German Society of Anesthesia and Intensive Care Medicine

Two surveys initiated by the Neuroanesthesia Research Group of the German Society of Anesthesia and Intensive Care Medicine examined the practice of intraoperative monitoring during intracranial procedures in Germany in 1991 and 1997. Questionnaires were mailed to departments that were registered members of the German Society of Anesthesia and Intensive Care Medicine and that provided neuroanesthesia service on a routine basis in 1991. In 1997, the survey was repeated in the 1991 respondents. In 1991, 68 departments and in 1997, 44 departments returned completed questionnaires, indicating a response rate of 87% for 1991 and of 65% for 1997. Compared with 1991, the standards for monitoring, such as surveillance of oxygenation, ventilation, circulation, and body temperature, were universally applied in adult and pediatric patients in 1997. Overall, there was a 20% increase in neuromuscular blockade monitoring and in the use of electroencephalography and evoked potentials in 1997 compared with 1991. Further brain-specific monitoring was rarely provided in 1997. Overall, jugular venous oximetry was used in 20% and transcranial Doppler ultrasonography in 15% of responding hospitals. To detect venous air embolism in sitting patients, 75% of all responding hospitals used precordial Doppler ultrasonography in both years, whereas transesophageal echocardiography was more often used in 1997 (38%) as compared with 1991 (17%).

IMPLICATIONS

Standards of anesthetic monitoring were surveyed in neuroanesthesia in Germany in 1991 and 1997. Central nervous system monitoring was not the standard of practice.

Left ventricular pressure-area relations as assessed by transoesophageal echocardiographic automated border detection: comparison with conductance catheter technique in cardiac surgical patients

The aim of this study was to validate measurements of intraoperative left ventricular (LV) area by transoesophageal echocardiography against simultaneous measurements of LV volume by conductance catheter (CC) in cardiac surgical patients with normal systolic LV function. Echo area was compared with CC volume during steady state and during acute changes of pre- and afterload by partial clamping of the inferior vena cava and the ascending aorta in eight patients scheduled for coronary artery bypass grafting. At steady state, Bland-Altman analysis of 32 recordings revealed a bias (SD) of 0.6% (2.5%) between echo area and CC volume, related to the initial values of end-diastolic area (100% area) and volume (100% volume), respectively. During loading interventions, bias between the two methods, as assessed by 112 measurement sequences, was 0.5% (3.7%) during aortic occlusion and -3.9% (4.4%) during cava occlusion at end-systole (P < 0.0001); at end-diastole, this bias was 1.3% (4%) during aortic occlusion and 0.2% (5.7%) during cava occlusion (P < 0.0001). Intraoperative area measurements with transoesophageal echocardiography in cardiac surgical patients with normal systolic LV function show good correlation with CC volume measurements under steady-state conditions. During acute unloading by vena cava occlusion, the resulting small end-systolic echo area measurements differ significantly more from CC volume measurements than during acute increase in afterload by aortic occlusion.

Long-term results of facial nerve function after acoustic neuroma surgery--clinical benefit of intraoperative facial nerve monitoring

The goals in acoustic neuroma surgery should be the total removal of tumor and preservation of facial nerve function. The aim of this study is to establish the benefit of intraoperative monitoring for the total removal of tumor and the long-term result of facial nerve function after surgery. Thirty-two patients, who were operated on between 1985 and 1995, were divided into two groups: an unmonitored (n = 14) and a monitored (n = 18) group. Postoperative facial nerve function was followed by a modified House-Brackmann grading (H&B) immediately (initial), and at 1 week, 1 month, 6 months and 1 year (final) after surgery. A final H&B grade of I/II was taken as the preservation of facial nerve function. Facial nerves were preserved anatomically in all cases. A total tumor removal was accomplished in 21% of unmonitored group and in 72% of monitored group patients. Final H&B (I/II) was achieved in 36% of unmonitored group and in 83% of monitored group patients. All 9 patients with initial H&B (I/II) had final H&B (I/II). None of 5 patients with initial H&B (V/VI) had final H&B (I/II). However, 3 patients showed late-recovery of facial weakness at 6 months after surgery. Eighteen patients with initial H&B (III/IV) had various degrees of final facial weakness. Among them, 12 patients showed early-recovery at 1 month after surgery. In conclusion, facial nerve monitoring during acoustic neuroma surgery is useful to improve the rates of total removal of tumor and functional preservation of facial nerve. We can expect final degrees of facial weakness by initial degrees in conjunction with sequential changes in postoperative facial weakness.

Radio-contrast imaging of the rectum prior to colostomy closure for rectal trauma--is routine use still justified?

This retrospective study was undertaken to assess the yield of radio-contrast imaging of the rectum before closure of colostomy following extraperitoneal rectal trauma. Sixty-nine patients (63 males) underwent colostomy closure in 36 months. All radio-contrast studies (colograms) performed before closure of colostomy were normal, and there were no deaths following closure. This study demonstrated that the yield from pre-closure radio-contrast imaging of the rectum after rectal trauma was negligible and did not influence colostomy closure. We conclude that while it may be appealing to suggest abandonment of its routine use, this investigation needs to be further evaluated prospectively with special attention given to injury to associated structures such as bone, bladder and vagina.

Field-by-field evaluation of intraoperative transoesophageal echocardiography interpretative skills

A quality assurance system is essential for the credibility and structured growth of anaesthesiology-based transoesophageal echocardiography (TEE) programmes. We have developed software (Q/A Kappa), involving a 400-line source code, capable of directly reporting kappa correlation coefficient values, using external reviewer interpretations as the 'gold standard', and thereby allowing systematic assessment of the validity of intraoperative echocardiographic interpretation. This paper presents assessment of the validity of 240 intraoperative anaesthesiologists' echocardiographic interpretations, and, in addition, the results of field testing of this prototypical software. Data, derived from consecutive cardiac surgery patients, consisted of standardized two-dimensional transoesophageal echocardiographic, colour flow and Doppler imaging sequences. Intraoperative and off-line 'gold standard' TEE interpretations were compared for 19 fields or variables using the Q/A Kappa program. The kappa correlation coefficients were highly variable and dependent on the examination field, ranging from 0.08 for apical regional wall motion scores to 1.00 for tricuspid regurgitation grade, left atrial measurement, aortic valve anatomy and left ventricular long axis and short axis global function. The correlation coefficients were also operator dependent. These data (480 interpretations) were also manually integrated into the equation required for calculation of values of the variable kappa correlation coefficient. The relationship between Q/A Kappa-derived values and manually calculated values was highly significant (p < 0.001; r = 1.0). The implications and possible explanations of the results for particular examination fields are discussed. This study also demonstrates successful seamless functioning of this software program from data entry, segmentation into tables and valid statistical analysis. These findings suggest that it is practical to provide sophisticated continuous quality improvement TEE data on a routine basis.

[Anesthesia monitoring: degree of compliance with guidelines in Austria]

PURPOSE

For the first time an evaluation of standard anesthetic monitoring was performed according to the guidelines of the Austrian Society for Anesthesiology, Resuscitation und Intensive Care Medicine (OGARI).

METHODS

A questionnaire was delivered to all medical institutions performing anesthesia in Austria. A descriptive statistical evaluation was performed on all returned and completed questionnaires.

RESULTS

Generally, there is a high standard in compulsory monitoring and in PACU (actual compliance > 99%/85.8%). Supplemental equipment is required for disconnection alarm and measurement of inspired oxygen concentration (actual compliance: 98.3%/98.9%). Furthermore, measurement for inspired concentration of volatile anesthetics and relaxometry (actual compliance 68.7%/47.3%) has yet to be completed. University departments and regional hospitals have comparable standards (82.2% vs. 79.6%).

CONCLUSIONS

For the first time an Austrian-wide evaluation of anesthetic monitoring investigated the compliance with the 1992 recommendations of the Austrian Society of Anesthesiology, Resuscitation and Intensive Care Medicine. The data demonstrate that these recommendations including the anesthetic monitoring equipment have already been implemented to a high degree.

Accuracy of blood loss determination by health care professionals

Patients undergoing surgery will likely experience some degree of blood loss. There is much literature examining effects of blood loss, but little was found that examined accuracy of estimation of blood loss. The research question for this study was: How accurate are surgical health care professionals in their estimations of blood loss? This study was a pre-experimental between-subject design that used a convenience sample of 85 volunteers who worked in the surgical and postsurgical units of a rural southern 450-bed hospital. The participants viewed 1 of 3 randomly chosen samples of laparotomy pads with variable amounts of blood and saline. Only the researchers knew the exact amount contained on the pads. The variables that were examined and were compared included the professional group, years of experience in surgery or the postanesthesia care unit (PACU), and their estimation of blood loss. Their estimation of blood loss was compared with the actual amount of blood to determine whether one group was more accurate than another statistically and whether increasing years of experience improved accuracy. The statistical tests used were simple and multiple regressions.

Efficacy of intraoperative monitoring for pediatric patients with spinal cord pathology undergoing spinal deformity surgery

STUDY DESIGN

A retrospective study of 38 pediatric patients with spinal cord pathology who underwent corrective spinal deformity surgery from January 1989 through June 1998.

OBJECTIVES

To report reliability and specificity in obtaining intraoperative data in this population. These data were compared with monitoring results obtained in a group of pediatric patients with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Reports in the literature suggest intraoperative monitoring for patients with spinal cord pathology may be of limited value. No optimal monitoring protocol has been suggested for this population.

METHODS

The study group consisted of 38 pediatric patients with a diagnosis of spinal cord pathology who underwent corrective spinal deformity surgery from January 1989 through June 1998. All patients had lower extremity function. Somatosensory and neurogenic motor evoked potentials were used to monitor neurologic status during surgery. These data were compared with data obtained in 429 pediatric patients with idiopathic scoliosis. Study patients were divided into Group I, those who had had spinal cord surgery (n = 20), and Group II, those who had not (n = 18).

RESULTS

Somatosensory evoked potentials were obtained in 93.2% and remained consistent with baselines in 87.2% of the study group patients. Neurogenic motor evoked potentials were obtained in 50.8% of the study subjects and remained consistent in 76.6% of those cases. The false-positive rate was 27.1% in the study group, compared with 1.4% in the group with idiopathic scoliosis. The study group had no true-positive or false-negative findings. Group I data differed from Group II data.

CONCLUSIONS

Intraoperative monitoring should be used in patients with spinal cord pathology who undergo surgery for spinal deformity. Monitoring should not miss a neurologic deficit but demonstrates greater variability, resulting in more frequent use of an intraoperative wake-up test.

What intraoperative monitoring makes sense?

The routine practice of monitoring oxygenation, ventilation, circulation, and temperature during surgery is now the standard of care. However, with the possible exception of pulse oximetry and capnography, extensive physiologic monitoring has not been shown to reduce the incidence of adverse anesthetic-related events. Monitors are useful adjuncts, but they alone cannot replace careful observation by a vigilant anesthesiologist.

[Neuromuscular monitoring. Standard procedures]

In this article current indications and limitations of neuromuscular monitoring are reviewed. Attention is mainly focused on detection of residual curarisation. New insights in the pathophysiological consequences of residual neuromuscular blockade and the actual criteria of complete recovery are discussed. Surprisingly in this context, despite the benefit of neuromuscular monitoring, its utilisation in clinical practice is rather an exception than the routine. A lack of standardisation of neuromuscular monitoring is probably the major problem on the way to a widespread utilisation of the monitoring.

Near-infrared reflected spectroscopy and electroencephalography during carotid endarterectomy--in search of a new shunt criterion

The aim of this clinical study was to evaluate cerebral oximetry with near-infrared reflected spectroscopy (NIRS) as a monitoring system during carotid endarterectomy. The cross-clamping changes of cerebrovascular hemoglobin oxygen saturation (cereb. O2 satn.) were compared with data from a processed EEG analysis. Using the EEG as the gold standard we try to define a new shunt criterion based on near-infrared spectroscopy. 102 patients were studied. During cross-clamping the percentual decrease of cereb. O2 satn. was calculated. The relation between EEG and cereb. O2 satn. is described in terms of sensitivity and specificity, and is graphically shown in a Receiver Operator Characteristic (ROC) curve. At a cut-off value of 5% decrease or more for the cereb. O2 satn., a sensitivity of 100% was found. However, the specificity was only 44%. Higher cut-off values resulted in a gradual increase of the specificity at the expense of a significant decrease of the sensitivity. In conclusion, improved validation and calibration techniques are necessary before this technique may be used for relevant assessment of cerebral oxygenation during carotid surgery. In particular, in order to define a new shunt criterion, the focal aspect of this new technique is probably one of the limitations.

Neurogenic motor evoked potentials: a prospective comparison of stimulation methods in spinal deformity surgery

Neurogenic motor evoked potentials (NMEPs) elicited by spinal cord stimulation via the spinous processes (SP-NMEP) have been widely accepted as a sensitive method of monitoring motor tract function. SP-NMEP requires additional surgical dissection as well as electrodes within the wound, making the method somewhat inconvenient. A less invasive percutaneous method of spinal cord stimulation (PERC-NMEP) has more recently been described. We prospectively compared the SP-NMEP and PERC-NMEP methods in 184 patients undergoing 225 surgical procedures. Although SP-NMEP responses were more readily obtainable than PERC-NMEP, the reliability of the two methods was not significantly different. Both methods were found to be sensitive to neurologic deficit. The present study suggests that when responses are obtained, the percutaneous method is reliable enough to obviate the spinous process method of monitoring the motor function of the spinal cord.

International variation in anesthesia care during cataract surgery: results from the International Cataract Surgery Outcomes Study

OBJECTIVES

To describe international variation in anesthesia care and monitoring during cataract surgery and to discuss its implications for cost and safety.

METHODS

A standardized questionnaire was sent to random samples of ophthalmologists in the United States, Canada, and Barcelona, Spain, and to all ophthalmologists in Denmark. The survey was conducted in 1993 and 1994. Certified ophthalmologists who had performed 1 or more cataract extractions in the previous year were eligible for enrollment.

RESULTS

The response rates were 62% in the United States (n=148), 67% in Canada (n=276), 70% in Barcelona (n=89), and 80% in Denmark (n=82). The anesthetic technique for cataract surgery varied significantly between sites (P<.001). Surgeons reported that retrobulbar blocks were used for 46% of the cataract extractions in the United States, 70% in Canada, 66% in Denmark, and 31% in Barcelona. In Barcelona, general anesthesia was used for 23% of the cataract extractions; it was used for less than 3% of the extractions at the other 3 sites. Peribulbar blocks or topical anesthesia was used for the remaining extractions. In the United States, Canada, and Barcelona, surgeons reported that vital functions were monitored during more than 97% of the extractions and anesthesia surveillance was used during more than 78% of the extractions. In Denmark, ophthalmologists reported that vital functions were monitored and anesthesia surveillance was used for 1% of the cataract extractions (P<.001).

CONCLUSIONS

Substantial international variation in anesthesia care and monitoring during cataract surgery was observed. The findings suggest a need for further research to determine whether less intensive monitoring is cost-effective.

Fingertip temperature during cardiopulmonary bypass

Temperature changes in the nasopharynx, fingertip, forearm and extracorporeal circuit were continuously monitored, starting 10 min before and up to 16 min into the rewarming period of hypothermic (32 degrees C) cardiopulmonary bypass in 14 patients operated on for coronary artery revascularization. Arterial blood temperature was the first to increase after starting rewarming, followed by the nasopharynx and the fingertip temperatures. Fingertip temperature started to increase abruptly 6.2 (2.02 SD) min after rewarming started. At this point, nasopharyngeal temperature was 34.2 degrees C (1.42 SD) and took a further 8.3 min to reach 37 degrees C. Assuming that increasing fingertip temperature indicates a central thermoregulatory response to warming, we suggest that nasopharyngeal temperature is a poor monitor of brain temperature. We also suggest that fingertip temperature may be used to monitor the point at which cerebral temperature reaches 'normothermia'. Further body warming, using arterial temperatures > or = 39 degrees C, should be avoided because of the danger of brain hyperthermia.

Intra-arterial blood gas monitoring system: more accurate values can be obtained

OBJECTIVE

To compare values measured by a continuous intra-arterial blood gas monitoring system with those measured by conventional blood gas analyzer for the assessment of the clinical performance of a new device for measurement of PaO2, PaCO2, and arterial pH.

METHODS

Forty-six patients undergoing cardiopulmonary bypass were enrolled in this study. All patients had a continuous intra-arterial sensor (PB 3300) placed into the radial artery through a 20-gauge catheter. A total of 319 arterial blood gas and pH values were obtained for comparison with a conventional blood gas analyzer. The measurements were performed every 12 hrs after the initial in vitro calibration of the sensor for each patient.

RESULTS

Measurements were made over a range of 12 to 192 hrs. The overall bias and precision determined by the two methods were 4.5 and 17.1 mmHg for PaO2; 4.5 and 6.2 mmHg for PaCO2; and 0.009 and 0.035 for pH, respectively. For the range of PO2 less than 150 mmHg, the bias and precision improved to 4.2 and 9.5 mmHg. The sensor-derived PCO2 value, PCO2 (IABG), increased significantly more than the conventional blood gas analysis value, PCO2(ABG), even within 72 hrs (2.8 and 4.1 mmHg). The relationship between the two measurements can be described as: PCO2(IABG)/PCO2(ABG) = 1 + 0.0026.t where t is the time period of use (in hours). By correcting the PCO2(IABG) value using this formula, the overall bias and precision of the values measured by two methods decreases to -0.4 and 3.6 mmHg.

CONCLUSIONS

The PO2 and pH values derived from an intra-arterial blood gas monitoring system agreed well with the values measured by a conventional blood gas analyzer. However, the PCO2 value must be corrected due to an increase of drift, especially with extended use for more than 72 hours.

Attitudes to the Association of Anaesthetists recommendations for standards of monitoring during anaesthesia and recovery

A questionnaire was sent to 293 anaesthetists in the West of Scotland to assess their attitudes to the recommendations for standards of monitoring during anaesthesia and recovery published by the Association of Anaesthetists of Great Britain and Ireland. Such standards are considered achievable and affordable in terms of costs and allow the early detection of events occurring during anaesthesia, which might lead to injury to the patient. The survey shows that there is wide acceptance of the recommendations by anaesthetists of all grades, with resultant improvements in the quality of patients care.

Attendance of the anaesthesiologist to the patient. National recommendations for standard of anaesthetic practice

The national recommendations for standard of anaesthetic practice in six countries of the European Community are compared with respect to the attendance of the anaesthesiologist to the patient. These standards apply to anaesthesia, major regional anaesthesia and sedation administered by anaesthesiologists. The attendance to the patient varies from strict continuous presence of the anaesthesiologist to observation of the patient by a non-medical assistant and the anaesthesiologist taking care of another anaesthetized patient. Items which all standards should mention are defined.

[Multiplane transesophageal echocardiography for the monitoring of cardiac surgery]

Multiplane transesophageal echocardiography (TEE) allows visualization of the heart and great vessels through an infinite number of imaging planes and improves the diagnostic capabilities of mono and biplane TEE. This study was undertaken to test whether MTEE is a useful intraoperative monitoring method during cardiac surgery. Intraoperative multiplane TEE was performed in 200 patients (mean age 56 +/- 19 years) as a part of the routine clinical care. We systematically acquired cardiac images from the gastric fundus (short and long axes of the ventricles), lower esophagus (four-chamber, two-chamber, and long axis), upper esophagus (13 views concerning the aorta, pulmonary artery, left and right atrium, systemic and pulmonary veins, coronary arteries, right ventricular outflow tract), and searched for complete views of the thoracic descending aorta. All views analyzed in the preoperative (immediately before cardiopulmonary bypass), intraoperative and postoperative phases evaluating: the angle between current and 0 degree at which each view was obtained; the success rate of each view; the usefulness of the different views in providing essential additional clinical information compared to 0 degrees and 90 degrees of the traditional biplane TEE. Most views of the heart and great vessels were visualized in oblique planes, and other views were significantly improved thanks to slight angle corrections. Multiplane TEE was particularly useful in the preoperative and postoperative phases of aortic dissection (11 cases), mitral valve repair (13 cases), left ventricular aneurysmectomy (9 cases), right atrial thrombosis (1 case), positioning of left ventricular hemopump (2 cases), mitral-aortic endocarditis (3 cases), bleeding from proximal suture of an aortic heterograft (1 case).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac output monitoring by echocardiography: should we pass on Swan-Ganz catheters?

Transesophageal echocardiography offers a noninvasive technique for the continuous monitoring of cardiac performance. The combination of 2-dimensional echocardiography and Doppler velocitometry provide assessment of cardiac anatomy, valve function and, ventricular loading conditions. Although transesophageal echocardiography has become accepted for perioperative monitoring, it is typically used in conjunction with Swan-Ganz catheterization. To supplant Swan-Ganz catheters, an echocardiographic technique to monitor cardiac output is necessary. Despite considerable effort to achieve this goal, a satisfactory technique has been difficult to realize. This paper discusses the role of cardiac output monitoring in perioperative care and critically examines echocardiographic techniques for cardiac output monitoring.

Thermodilution right ventricular ejection fraction measurement reproducibility--a study in patients undergoing coronary artery bypass graft surgery

OBJECTIVE

To assess the effects of heart rate, right ventricular systolic performance (ejection fraction), chamber dimensions, and flow rate (cardiac index) on the reproducibility of algorithm-derived triplicate thermodilution right ventricular ejection fraction measurements.

DESIGN

Prospective study; combined hemodynamic and echocardiographic clinical evaluation.

SETTING

Operating room in a university hospital.

PATIENTS

Twenty-one coronary artery bypass graft patients.

MEASUREMENTS AND MAIN RESULTS

The right atrial delivery site was positioned by analysis of transduced pressure waveform and echocardiographic imaging of tracer agitated saline cavitations. Measurement reproducibility was quantified by determining the variation (standard deviation) within 101 triplicate thermodilution measurement sets. There was no significant relationship between measurement reproducibility and estimates of right atrial area (21.6 +/- 6.9 cm2), diameter (5.1 +/- 0.8 cm) and supero-inferior length (5.1 +/- 0.9 cm) and right ventricular maximal minor axis diastolic diameter (4.21 +/- 1.05 cm). Reproducibility was also unrelated to right ventricular end-diastolic volume index (97.9 +/- 32.7 mL/m2) and cardiac index (2.9 +/- 0.9 L/min/m2). Measurement reproducibility was directly related to mean right ventricular ejection fraction (0.39 +/- 0.14) and inversely related to heart rate (80.8 +/- 18.6 beats/min) (p < .01 and < .001, respectively).

CONCLUSIONS

Thermodilution-derived right ventricular ejection fraction measurement reproducibility was unrelated to estimates of right atrial and ventricular dimensions and cardiac index. Measurement reproducibility was a direct function of right ventricular systolic performance and an indirect function of heart rate. Measurement should be interpreted with these constraints in mind.

Electrically evoked auditory brainstem response monitoring of auditory brainstem implant integrity during facial nerve tumor surgery

Evoked potentials identified as electrically evoked auditory brainstem responses (EABRs) have been recorded from a patient in response to electrical stimulation of the cochlear nucleus via an auditory brainstem implant. Recording such EABRs during surgery for removal of an ipsilateral facial nerve tumor provided a means to monitor the integrity of the implant. The presence of stable EABRs similar to those obtained before surgery indicated that the lead wires had not been severed and that the implanted electrodes had not been dislodged. EABR recording may also be useful for assisting with positioning the stimulating electrodes during initial implantation surgery, by verifying that stimulation can activate the auditory system.

Laparoscopic surgery--basic armamentarium

The introduction of laparoscopic techniques into standard intracavitary surgery has received widespread acceptance in North American surgical practice in a very short time. To complete these procedures successfully a basic armamentarium is required by surgeons. The equipment should provide safe conduct of the procedure and maximum flexibility in the types of surgical procedures to be undertaken. The basic laparoscopic equipment needed to facilitate minimal-access-site surgery is reviewed, from the operating table and lighting in the operating room through optics, cameras and television monitors to the instruments and agents needed for the surgical techniques and for securing hemostasis.

The effect of suprarenal cross-clamping on abdominal aortic aneurysm repair

Two hundred five patients who underwent elective abdominal aortic aneurysm repair were divided into two groups: those who underwent infrarenal cross-clamping alone (n = 166) and those who underwent suprarenal cross-clamping alone or combined with infrarenal cross-clamping (n = 39). Mortality was comparable between groups (1.2% for infrarenal cross-clamping vs 2.6% for suprarenal cross-clamping). Transient renal insufficiency was more frequent in the suprarenal group than in the infrarenal group (28% vs 10%), but dialysis rates (3% for suprarenal vs 2% for infrarenal) were similar. Cardiac morbidity was comparable between groups as well. Operating room data reflected the technical challenge of complex aneurysm repairs. The retroperitoneal approach was the preferred exposure in the suprarenal group since better access to the suprarenal aorta may be achieved with this technique. While abdominal aortic aneurysm repairs requiring suprarenal cross-clamping remain a technical challenge, the risks are not formidable and suprarenal cross-clamping should be considered when confronted with difficult periaortic dissection.

[Comparative analysis of the criteria for surveillance and monitoring in anesthesia, resuscitation and pain therapy. Recommendation of the Sociedad Española de Anestesia y Reanimación]

INTRODUCTION

One part of morbidity and mortality associated with anesthesia is due to accidents. It is thought that an additional monitoring can prevent and avoid most of anesthetic accidents.

OBJECTIVES

In order to improve patient's safety and quality of anesthesia, Harvard University hospital approved in 1985 the rules for intraoperative monitoring. These were adopted by the American Society of Anesthesiologists (ASA) in 1986. In line with this procedure, professional associations of several countries pronounced their own rules. SEDAR did it in 1989. The purpose of this study was to compare spanish rules with those of America (Harvard and ASA), Australia, England and France.

RESULTS

Comparative analysis revealed that the spanish norms are more extensive since they include not only the intraoperative anesthetic activities, but also those related to recovery, pain, and obstetric anesthesia. However, it has some deficiencies such as the lack of a periodical revision, and of an adaptative period and assistance to the anesthesiologist provided by auxiliary personnel. Successful points were the recognition that pulse oximetry is essential, the preoperative verification of all material, and, more importantly, is the only one that considers essential capnography in the assessment of ventilation and pulse oximetry during regional anesthesia and postoperative phase.

CONCLUSION

Spanish norm is comparable to that of the other countries considered in this study. It shows important successful points and at the same time some significant deficiencies.

Standards of practice in anaesthesia--intra-operative monitoring

Intra-operative monitoring practice during anaesthesia was studied in a randomised selection of hospitals in different categories. Questionnaires from 45 anaesthetists in 20 hospitals provided information on 973 cases. The study showed that in 11% of cases the patient was left at some stage during anaesthesia without the attention of a medical practitioner and that in 7% of cases no record was made of the anaesthetic or of the parameters monitored. Types of monitoring varied considerably between hospitals and often fell short of acceptable minimal standards. Pulse oximetry, which is considered essential, was used in only 53% of cases. One in 18 cases was associated with a peri-operative critical incident and in 7 cases a critical incident occurred where the monitoring was deemed to be inadequate. Pulse oximetry would have assisted the anaesthetist in 6 of these 7 cases. In 3% of cases the anaesthetist admitted to fatigue during the procedure. This study highlights deficits in anaesthetic practice and in available equipment, both of which require urgent attention.

[The accuracy of 4 different oximeters for continuous monitoring of mixed venous oxygen saturation during abdominal aortic surgery]

Several systems for mixed-venous oximetry are now available. There are one three-wave-length system (Abbott) and three two-wave-length systems with (Spectramed) and without automatic correction for hemoglobin or hematocrit (Edwards). The purpose of this prospective randomized study was to compare the different systems and to examine the accuracy of continuous mixed-venous oximetry during abdominal aortic surgery. Eighty patients had a radial artery cannula and one of the following fiberoptic pulmonary artery catheters inserted before induction of anesthesia: Swan-Ganz oximetry TD catheter (Edwards), Swan-Ganz flow-directed oximetry thermodilution paceport catheter (Baxter, Edwards Division), SpectraCath STP (Spectramed), and Opticath (Abbott). Mixed-venous O2 saturation was monitored by oximetry computers: SAT-1 (Edwards), SAT-2 (Baxter, Edwards Division), Hemopro2 (Spectramed), and Oximetrix 3 (Abbott). As a method of reference, mixed-venous blood samples were drawn and immediately analyzed by an OSM3-Hemoximeter. Data sets were obtained at eight predetermined times. Hemoglobin was kept constant at +/- 1 g.dl-1. Continuous oximetry in comparison to in-vitro measurements yielded a correlation coefficient of r = 0.873 (P less than 0.0001) and a value of bias and precision (b +/- p) of -0.9 +/- 2.6% for the SAT-1, r = 0.815 (P less than or equal to 0.0001) and b +/- p = -2.2 +/- 2.5% for the SAT-2, r = 0.901 (P less than or equal to 0.0001) and b +/- p = 0.35 +/- 2.5% for the Hemopro2, and r = 0.920 (P less than or equal to 0.0001) and b +/- p = 0.1 +/- 1.8% for the Oximetrix 3, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

HCFA mandates new quality screens (more emphasis on histories and physicals and perioperative monitoring)

As standards of care are redefined based on new technology or new constructs of what constitutes quality, we can expect changes in the criteria by which our clinical activities are assessed. This is certainly true for peer review conducted under PRO programs, since the starting point for review is the application of criteria and screens. Review criteria are essentially developed by the PROs and, in Pennsylvania, with assistance of specialty society liaisons. The generic quality screens are HCFA-developed, and their use is mandated. Recently, all PROs received a Directed Change Order (DCO) in which newly revised outpatient generic quality screens were released.