Evaluation of triage decisions for intensive care admission.

OBJECTIVE: To assess physician decision-making in triage for intensive care and how judgments impact on patient survival. DESIGN: Prospective, descriptive study. SETTING: General intensive care unit, university medical center. INTERVENTIONS: All patients triaged for admission to a general intensive care unit were studied. Information was collected for the patient's age, diagnoses, surgical status, admission purpose, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and mortality. The number of available beds at the time of triage and reasons for refused admission were obtained. MEASUREMENTS AND MAIN RESULTS: Of 382 patients, 290 were admitted, 92 (24%) were refused admission, and 31 were admitted at a later time. Differences between admission diagnoses were found between patients admitted or not admitted (p < .001). Patients refused admission had higher APACHE II scores (15.6+/-1.5 admitted later and 15.8+/-1.4 never admitted) than did admitted patients (12.1+/-.4; p < .001). The frequency of admitting patients decreased when the intensive care unit was full (p < .001). Multivariate analysis revealed that triage to intensive care correlated with age, a full unit, surgical status, and diagnoses. Hospital mortality was lower in admitted (14%) than in refused patients (36% admitted later and 46% never admitted; p < .01) and in admitted patients with APACHE II scores of 11 to 20 (p = .02). The 28-day survival of patients was greater for admitted patients compared with patients never admitted (p = .01). CONCLUSIONS: Physicians triage patients to intensive care based on the number of beds available, the admission diagnosis, severity of disease, age, and operative status. Admitting patients to intensive care is associated with a lower mortality rate, especially in patients with APACHE scores of 11 to 20.

Helium versus oxygen for tracheal gas insufflation during mechanical ventilation.

OBJECTIVE: To evaluate and compare the effect of tracheal gas insufflation using two gases with different physical properties, helium and oxygen, as an adjunct to conventional mechanical ventilation in patients with respiratory failure. DESIGN: Prospective, intervention study. SETTING: General intensive care unit in a tertiary university medical center. PATIENTS: Seven sedated and paralyzed patients with respiratory failure of various etiologies. All patients were ventilated in the volume-control mode (tidal volume 5 to 7 mL/kg). Inclusion criteria were PaCO2 of > or =50 torr (> or =6.7 kPa), together with peak inspiratory pressure of > or =35 cm H2O and respiratory rate of > or =14 breaths/min. INTERVENTIONS: All patients were intubated with an endotracheal tube that had an additional lumen opening at its distal end, through which tracheal gas insufflation was administered. The tracheal gas insufflation was applied continuously throughout the respiratory cycle at three flow rates (2, 4, and 6 L/min) with two gases, oxygen and helium, while the ventilatory settings were maintained constant. MEASUREMENTS AND MAIN RESULTS: In addition to airway pressures and arterial blood gases, the relative efficacy of tracheal gas insufflation with each gas was estimated using a "coefficient of efficiency" (which we defined as the change in PaCO2/peak inspiratory pressure) compared with baseline measurements. Tracheal gas insufflation with both gases decreased PaCO2 significantly (p < .05) at all flow rates. This effect was accompanied by an increase in airway pressure with both gases (oxygen and helium). However, at flow rates of 6 L/min, tracheal gas insufflation with helium resulted in lower peak inspiratory pressure than with oxygen. Tracheal gas insufflation with helium was more effective (as estimated by the coefficient of efficiency) than with oxygen at all flow rates (p < .05). CONCLUSION: In volume-controlled, mechanically ventilated patients with respiratory failure, tracheal gas insufflation with helium might be suggested as an alternative to oxygen.

Myocardial ischemia in sedated patients undergoing fiberoptic bronchoscopy.

STUDY OBJECTIVE: To study the incidence of myocardial ischemia and related hemodynamic alterations in sedated patients undergoing fiberoptic bronchoscopy (FOB). DESIGN: Prospective study. SETTING: Tertiary care, university hospital. PATIENTS: Twenty-nine patients, age 50 years or older, undergoing elective FOB. INTERVENTIONS: Myocardial ischemia was assessed by continuous ECG monitoring beginning 30 min before, and until 2 h after FOB. MEASUREMENTS AND RESULTS: During FOB, there was a significant rise in heart rate (89+/-3 [mean+/-SE] to 120+/-4 beats/min) and fall in oxygen saturation (95+/-1 to 90+/-1%). There was no significant rise in systolic or diastolic BP. Five patients (17%) had myocardial ischemia during FOB that lasted 20+/-8 min. Their demographic and pre-FOB characteristics were not different from the other patients. Compared to baseline values, a significant rise in heart rate, a fall in oxygen saturation, and no significant change in BP were observed during FOB in patients, both with or without ischemia. Although not statistically significant, ischemia was associated with more protracted procedures. CONCLUSIONS: Myocardial ischemia may develop in elderly patients undergoing FOB. This observation encourages the routine use of ECG and oximetry during FOB, allowing for early intervention to prevent the dangerous combination of hypoxia, tachycardia, and myocardial ischemia. Moreover, this study suggests that methods to ensure oxygenation during FOB should be adhered to, and that the routine administration of atropine should be reconsidered.

Continuous spinal anaesthesia using a standard epidural set for extracorporeal shockwave lithotripsy.

PURPOSE: Continuous spinal anaesthesia (CSA) offers considerable advantages over "single shot" spinal or epidural anaesthesia since it allows titration of anaesthesia using small doses of local anaesthetics (LA). We evaluated the feasibility of CSA using a standard epidural set for extracorporeal shockwave lithotripsy (ESWL). METHODS: Charts of 100 consecutive CSAs for ESWL were retrospectively reviewed. Lumbar CSA was performed using a 20G epidural catheter through an 18G Tuohy needle. The CSA was preplanned, or followed inadvertent dural puncture. Small LA boluses were injected to achieve the desired sensory level of anaesthesia. Demographic data, anaesthetic duration, LA doses, the most cephalad sensory level to pinprick, arterial blood pressure, heart rate, use of systemic sympathomimetics and complications were recorded. RESULTS: Mean age was 66.2 +/- 9.9 (SD). The ASA status was III-IV in 54.1% and 5.5% of the preplanned and inadvertent patients, respectively. In 85 anaesthetics, hyperbaric bupivacaine 0.1% (9.7 +/- 7.5 mg) was used as the sole anaesthetic. Sensory level was T4-T8. Maximal decrease in systolic and diastolic blood pressures and heart rate was 19.0 +/- 9.8%, 13.4 +/- 13.3%, and 7.2 +/- 11.7 respectively. Intravenous sympathomimetics were used in nine of 82 (11.0%) preplanned, and in six of 18 (33.3%) inadvertent anaesthetics. Post dural puncture headache appeared following two of 82 (2.5%) preplanned, and four of 18 (22.2%) inadvertent anaesthetics. No postanaesthetic neurological deficit was detected. CONCLUSION: Continuous spinal anaesthesia, using a standard epidural set and hyperbaric bupivacaine is feasible for ESWL in high risk patients. Inadvertent dural puncture does not preclude CSA under these circumstances.

Perioperative ischemia and cardiac complications in major vascular surgery: importance of the preoperative twelve-lead electrocardiogram.

PURPOSE: To investigate the associations between specific preoperative 12-lead electrocardiogram (ECG) abnormalities, perioperative ischemia, and postoperative myocardial infarction or cardiac death in major vascular surgery. METHODS: Two prospective studies on perioperative myocardial ischemia performed in two tertiary university hospitals were combined to include 405 patients. All preoperative ECGs were analyzed according to the Sokolow-Lyon criteria for left ventricular hypertrophy by investigators who were blinded to the patients' perioperative clinical course. Perioperative myocardial ischemia was detected by continuous ECG recording, and postoperative cardiac complications included myocardial infarction and cardiac death. RESULTS: A total of 19 postoperative cardiac complications occurred (two cardiac deaths and 17 myocardial infarctions). Voltage criteria for left ventricular hypertrophy (78 patients, 19%) and ST segment depression greater than 0.5 mm (98 patients, 24.2%) on preoperative ECGs were both significantly associated with postoperative myocardial infarction or cardiac death (odds ratio, 4.2 and 4.7; p = 0.001 and 0.0005, respectively) and with longer intraoperative and postoperative myocardial ischemia. In each of the two study groups, a preoperative ECG abnormality that involved voltage criteria, ST segment depression, or both (134 patients, 33.1%) was more predictive of postoperative cardiac complications than any other preoperative clinical variable, including a history of myocardial infarction or angina pectoris, diabetes mellitus, pathologic Q-wave by ECG, or preoperative myocardial ischemia. The combined duration of intraoperative and postoperative ischemia and the preoperative ECG with either voltage criteria or ST segment depression were the only independent factors associated with adverse cardiac events by multivariate analysis (p < or = 0.0001 and p = 0.02, respectively). CONCLUSION: Left ventricular hypertrophy and ST segment depression on preoperative 12-lead ECGs are important markers of increased risk for myocardial infarction or cardiac death after major vascular surgery.

[An in-hospital pain service: present activity and future trends].

Although significant progress has been made in the past 2 decades in our understanding of pain pathophysiology and in the development of new analgesic drugs and techniques, many patients still experience considerable pain during hospitalization. Unrelieved pain is common not only among patients undergoing surgery, but also in those with a variety of other medical problems. These findings led to the development of our in-hospital acute pain service. This in-hospital pain service has been active since the late eighties, treating both postoperative pain and non-surgical pain in hospitalized patients. During 1995, 2140 patients were treated totaling 8717 treatment days in 18 different medical units and departments. Overall success was more than 75%. We review our experience in treating in-patients who suffer from pain and discuss future trends and need for such a specialized service.

Reduction in pulmonary fibrosis in vivo by halofuginone.

Pulmonary fibrosis is a disorder causing a high mortality rate for which therapeutic options are limited. Therefore, the effect of halofuginone, a novel inhibitor of collagen type I synthesis, on bleomycin-induced pulmonary fibrosis was studied in rats. Pulmonary fibrosis was induced by intraperitoneal injections of bleomycin for seven consecutive days, and halofuginone was administered intraperitoneally every second day during the entire experimental period of 42 d. Collagen determination in the lungs and the examination of histologic sections showed that halofuginone significantly reduced fibrosis relative to the untreated control rats. We conclude that halofuginone is a potent in vivo inhibitor of bleomycin-induced pulmonary fibrosis, and that it may potentially be used as a novel therapeutic agent for the treatment of this dysfunction.

Positive end-expiratory pressure-induced hemodynamic changes are reflected in the arterial pressure waveform.

OBJECTIVE: To examine whether the hemodynamic changes due to mechanical ventilation with positive end-expiratory pressure (PEEP) can be assessed by the respiratory-induced variations in the arterial pressure waveform during normovolemia and experimental acute ventricular failure. DESIGN: Prospective, controlled experimental study. SETTING: Institutional experimental laboratory. SUBJECTS: Adult mongrel dogs. INTERVENTIONS: Experimental acute ventricular failure was induced by the infusion of pentobarbital (a cardiodepressant) and methoxamine (a vasoconstrictor), combined with volume loading. Both the control and acute ventricular failure groups were subjected to ventilation with incremental levels of PEEP up to 20 cm H2O. MEASUREMENTS AND MAIN RESULTS: Cardiac function was evaluated by cardiac output and left and right ventricular change in pressure over time (dP/dt) measurements. Arterial pressure waveform analysis was performed by measuring the systolic pressure variation, which is the difference between the maximal and minimal systolic blood pressure values during one mechanical breath. The components of the systolic pressure variation, namely, dUp and dDown, which are the increase and decrease in the systolic pressure during the mechanical breath relative to the systolic pressure during apnea, were also measured at each PEEP level. PEEP caused significant reduction of cardiac output in normovolemic dogs, and was associated with significant increases in systolic pressure variation and dDown. Acute ventricular failure decreased the variations in the systolic pressure and caused the dDown component to disappear. The application of PEEP did not affect cardiac output in dogs with acute ventricular failure, nor did it change systolic pressure variation and the dDown. CONCLUSIONS: Analysis of arterial pressure waveforms during mechanical ventilation reflected the decrease in cardiac output in dogs with normal cardiac function subjected to incremental PEEP. In dogs with acute ventricular failure in which PEEP did not affect cardiac output, the systolic pressure variation was similarly unaffected by PEEP. In the absence of cardiac output measurement during mechanical ventilation with PEEP, the analysis of the respiratory variations in the arterial pressure waveform may be useful in assessing changes in cardiac output.

Patient data management systems in anaesthesia: an emerging technology.

The purpose of this review is to define the expectations of an on-line automatic patient data management system (PDMS) into anaesthesia work-stations in and around the operating room suite. These expectations are based on review of available information in the medical literature, and trials of several systems that are available commercially, three of them in a more detailed fashion (i.e. Informatics, Datex and North American Drager). The ideal PDMS should: -- communicate with and capture the information from different monitors, anaesthesia machines and electronic gadgets (e.g., infusion pumps) used in the operating room (OR), while presenting selected relevant values and trends on a screen. -- inform the anaesthetist of deviations from preselected limits of physiological and technical values. In the future, the system will hopefully be upgraded to include an algorithm-based decision support system. -- communicate with the hospital mainframe computer, and automatically transfer demographic data, laboratory and imaging results, and records obtained during preoperative consultations. -- at the end of each anaesthetic procedure, create an anaesthetic record with relevant data automatically collected by the system, as well as that which was entered manually by the physician during the procedure. A copy of this anaesthesia file must be kept on a computerized archive system. None of the systems so far evaluated fulfilled all our expectations. We have therefore adopted approach for the gradual introduction of such a system into our OR environment over the next two to five years, during which expected improvements may be incorporated to upgrade the system.

A look into the nature and causes of human errors in the intensive care unit.

OBJECTIVES: The purpose of this study was to investigate the nature and causes of human errors in the intensive care unit (ICU), adopting approaches proposed by human factors engineering. The basic assumption was that errors occur and follow a pattern that can be uncovered. DESIGN: Concurrent incident study. SETTING: Medical-surgical ICU of a university hospital. MEASUREMENTS AND MAIN RESULTS: Two types of data were collected: errors reported by physicians and nurses immediately after an error discovery; and activity profiles based on 24-hr records taken by observers with human engineering experience on a sample of patients. During the 4 months of data collection, a total of 554 human errors were reported by the medical staff. Errors were rated for severity and classified according to the body system and type of medical activity involved. There was an average of 178 activities per patient per day and an estimated number of 1.7 errors per patient per day. For the ICU as a whole, a severe or potentially detrimental error occurred on the average twice a day. Physicians and nurses were about equal contributors to the number of errors, although nurses had many more activities per day. CONCLUSIONS: A significant number of dangerous human errors occur in the ICU. Many of these errors could be attributed to problems of communication between the physicians and nurses. Applying human factor engineering concepts to the study of the weak points of a specific ICU may help to reduce the number of errors. Errors should not be considered as an incurable disease, but rather as preventable phenomena.

Transfusion-related adult respiratory distress syndrome.

Leukocyte antibodies are the major cause of nonhemolytic transfusion reactions. One of the less frequent but severe forms of this reaction is the adult respiratory distress syndrome, or transfusion-related acute lung injury. This rare phenomenon is the result of leukocyte antibodies forming immune complexes with granulocytes, complement activation, sequestration of activated granulocytes in the pulmonary capillary bed, and their degranulation associated with release of proteolytic and cytotoxic substances. This cascade causes endothelial damage with increased capillary permeability. Plasma fluids and proteins accumulate in the interstitial and intra-alveolar spaces, leading to respiratory insufficiency. We present two patients with transfusion-related adult respiratory distress syndrome associated with leukocyte HLA antibodies, who were successfully treated in our hospital. The pathogenesis, diagnostic measures and treatment of this uncommon yet critical condition is discussed.

Importance of long-duration postoperative ST-segment depression in cardiac morbidity after vascular surgery.

Major vascular surgery is associated with a high incidence of cardiac ischaemic complications. By means of continuous perioperative electrocardiographic recording, we studied 151 consecutive patients undergoing major vascular surgery to find out the characteristics of any myocardial ischaemia and the relation to outcome. 13 (8.6%) patients had postoperative cardiac events (6 myocardial infarctions, 2 unstable angina, and 5 congestive heart failure). There were 342 perioperative ischaemic episodes shown by ST-segment depression; 164 (48%) occurred postoperatively. Postoperative ischaemic episodes were significantly longer than episodes before or during operations (3.2 vs 1.7 and 1.5 min per h monitored, respectively, p < 0.001). Both Detsky's cardiac risk index and long-duration (> 2 h) preoperative ischaemia were predictive of postoperative cardiac complications (odds ratios in univariate analysis 3.3, p = 0.03, and 7.2, p = 0.009, respectively). However, long-duration (> 2 h) postoperative ischaemia was the only factor significantly associated with cardiac morbidity in multivariate logistic regression analysis (odds ratio 21.7, p = 0.001). Long-duration ST-segment depression preceded most (84.6%) postoperative cardiac events, including myocardial infarctions, and no cardiac event was preceded by ST-segment elevation. 5 of the 6 postoperative myocardial infarctions were non-Q-wave infarctions. We conclude that long-duration subendocardial ischaemia, rather than acute coronary artery occlusion, may bring about postoperative myocardial injury and complications.

Brain edema and neurologic status following head trauma in the rat. No effect from large volumes of isotonic or hypertonic intravenous fluids, with or without glucose.

Disagreement exists regarding the need to restrict the administration of fluid and glucose following head injury to prevent cerebral edema and neurologic deterioration. We examined whether blood osmolality and glucose, neurologic outcome, and the development of brain edema following head trauma were altered by intravenous infusion of large volumes of isotonic or hypertonic fluids that contained or did not contain glucose. Fifty-five rats that survived ether anesthesia and closed head trauma (delivered using a weight drop device) were assigned to one of five groups. In the first group no fluid was infused. In the second group minimal volumes of saline were infused during placement of a jugular vein catheter. In the three remaining groups 10 ml.kg-1.h-1 of either total parenteral nutrition (TPN) (glucose 25%, amino acids 4.25%, 40 mEq/l sodium and 40 mEq/l potassium, 1935 mOsm/kg), dextrose 5% in 0.45% saline (495 mOsm/kg), or Haemaccel (isotonic plasma expander, 298 mOsm/kg) was infused via the jugular vein. Following head trauma and cannula placement, ether was discontinued. Neurologic severity score at 1 and 18 h after head trauma was used to assess neurologic outcome. A score between 0 and 6 was assigned by an observer who was blinded as to the experimental groups, with 0 representing no neurologic damage and 6 representing severe damage. Specific gravity of brain tissue samples containing gray matter and subcortical white matter from the traumatized and contralateral hemispheres was measured at 18 h after head trauma to determine the development of brain edema. There were no statistically significant differences in neurologic outcome and brain edema between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Combined spinal-epidural anesthesia].

Combined spinal and epidural anesthesia is a new regional anesthetic modality which combines the benefits of both the spinal and epidural approaches. 24 patients (11 after cesarean section and 13 after orthopedic operations on the lower limbs) were studied. Muscle relaxation and anesthesia were excellent, and regional anesthesia can be prolonged after the original spinal anesthesia wears off. No other anesthetics were needed. Methadone or morphine were given through the epidural catheter in the recovery room for postoperative analgesia. All patients were followed for 24 hours postoperatively.

Estimating anesthetic depth by electroencephalography during anesthetic induction and intubation in patients undergoing cardiac surgery.

Intravenous (IV) anesthesia titrated to continuous computer-processed electroencephalograms (EEGs) was studied in 32 consecutive patients undergoing cardiac surgery. Anesthesia was induced with fentanyl 50 micrograms/kg with no EEG monitoring (n = 16) or 25 to 50 micrograms depending on changes in EEG (n = 16). EEG, oxygen saturation by pulse oximeter, intra-arterial blood pressure (BP), central venous pressure (CVP), and pulmonary artery pressure (PAP) (n = 18) were monitored continuously. Cardiac output (CO), CVP, PAP, spectral-edge frequency for each hemisphere, and BP were recorded before induction, immediately before intubation, and 1 and 5 minutes after intubation. With EEG monitoring, intubation was performed when spectral-edge frequency decreased to 10 Hz or less. Recall and pain were investigated 2 to 12 weeks postoperatively. With EEG, the amount of fentanyl used before intubation was significantly lower (39.7 +/- 2 micrograms/kg; p less than 0.005) than without EEG (50 micrograms/kg). The decrease in BP (% change) was less with than without EEG; mean changes in BP between preinduction and preintubation were -7.4% +/- 3.8% and -16.5% +/- 3.1% and between preinduction and 1 minute after intubation 0.3% +/- 3.4% and -12.5% +/- 3.5%, respectively. Percent changes in mean BP between intubation and 1 minute after were 9.6% +/- 4.0% with EEG and 5.2% +/- 3.0% without EEG. No patient in either group had recall. The authors conclude that using EEG monitoring to estimate depth of anesthesia during induction and laryngoscopy may increase safety in high-risk patients undergoing cardiac surgery.

Protective effect of MK801 in experimental brain injury.

The effect of a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, MK801, was studied in a model of closed head injury in rats. Head trauma (HT) was induced over the left cerebral hemisphere by a calibrated weight-drop device. One or 3 h later, MK801 in saline was given i.p. in a single bolus of either 1, 3, or 10 mg/kg. The rats were killed at 4, 24, or 48 h after HT. Cortical tissue samples were taken from the injured zone and from the corresponding region of the contralateral hemisphere and analyzed for specific gravity (SG) by linear gradient columns. The neurological status of the traumatized rats was evaluated by a neurological severity score (NSS) 1 h after trauma and just before death. Pathological evaluation, based on size and severity of the lesion, was performed 24 and 48 h after HT on control and MK801-treated rats. A dose of 3 mg/kg MK801 given 1 h after trauma effectively prevented the reduction in tissue SG only at 24 h. The NSS could not be evaluated at 24 h after trauma because of the sedating effect of the drug. At 48 h posttrauma, however, the drug significantly improved the neurological state of the rats. No significant difference was found in the pathological score between treated and untreated rats. The results demonstrate neuroprotective properties of MK801, as expressed in two different variables--reduced edema formation and improved neurological recovery after HT. These findings support existing evidence that pharmacological intervention with NMDA receptor antagonist after head injury may be of clinical value in the management of head-injured patients.

Military medicine: trauma anesthesia and critical care on the battlefield.

This article presents a few of the basic guidelines that must be considered once a decision is made to provide anesthesia and advanced surgical care in the battlefield--or in civilian catastrophes (for example, terrorist incidents, and man-made or natural disasters) that resemble the battlefield. However, it must be stressed that the most central consideration in battlefield anesthesia is the selection, training, and experience of the battlefield anesthesiologist. There are strict guidelines for providing safe anesthesia under the dire circumstances of war or similar civilian circumstances; the properly trained and experienced TA/CCS, however, will be best able to deliver battlefield anesthesia and to improvise equipment and agents for its safest delivery in those circumstances.