Daniel Scheidegger

The Visual Analog Scale Allows Effective Measurement of Preoperative Anxiety and Detection of Patients' Anesthetic Concerns

The advent of managed care, reduction of costs, and advances in medical technology place increasing demands on anesthesiologists. Preoperative anxiety may go unnoticed in an environment that stresses increased productivity. The present study compares different methods for measuring preoperative anxiety, identifies certain patient characteristics that predispose to high anxiety, and describes the quantity and quality of anxiety that patients experience preoperatively. Seven hundred thirty-four patients participated in the study. We assessed aspects of anxiety by means of visual analog scales (VAS) and the State Anxiety Score of the Spielberger State-Trait Anxiety Inventory (STAI). The mean STAI anxiety score was 39 ± 1 (n = 486) and the mean VAS for fear of anesthesia was 29 ± 1 (n = 539). Patients feared surgery significantly more than anesthesia (P < 0.001). The VAS measuring fear of anesthesia correlated well with the STAI score (r = 0.55;P < 0.01). Young patients, female patients, and patients with no previous anesthetic experience or a previous negative anesthetic experience had higher anxiety scores. Patients worried most about the waiting period preceding surgery and were least concerned about possible awareness intraoperatively. Factor analysis of various anxiety items showed three distinct dimensions of fear: 1) the fear of the unknown 2) the fear of feeling ill, and 3) the fear for one’s life. Among these dimensions, fear of the unknown correlated highest with the anxiety measuring techniques STAI and VAS. The simple VAS proved to be a useful and valid measure of preoperative anxiety. Implications: The study of qualitative aspects of anxiety reveals three distinct dimensions of preoperative fear: fear of the unknown, fear of feeling ill, and fear for one’s life. Groups of patients with a higher degree of preoperative anxiety and their specific anesthetic concerns can be identified using the visual analog scale.

Repeated dural punctures increase the incidence of postdural puncture headache.

Previous studies have failed to find a significant correlation between the number of dural punctures and the incidence of postdural puncture headache (PDPH), questioning the hypothesis that leakage of cerebrospinal fluid (CSF) through the dural tear is the cause of PDPH.We hypothesized that insufficient statistical power of these studies was the cause for this unexpected finding, and reexamined whether repeated dural punctures increase the incidence of PDPH by analyzing prospectively collected data on 8034 spinal anesthetics. Uneventful spinal anesthetics, including a single subarachnoid injection of local anesthetics, occurred in 7865 (97.9%) cases, whereas failed spinal anesthetics requiring repeated dural puncture for a second subarachnoid injection of local anesthetics occurred in 165 (2.1%) cases. The two groups were similar with regard to age, sex, and ASA physical status. We found that repeated dural punctures significantly increased the incidence of PDPH. We conclude that increased risk of PDPH is a disadvantage of performing a second subarachnoid injection of local anesthetics after a failed spinal anesthetic. Moreover, this result suggests that leakage of CSF through the dural tear is the most plausible cause of PDPH. (Anesth Analg 1996;82:302-5)

Perioperative Myocardial Ischemia in Patients Undergoing Elective Hip Arthroplasty during Lumbar Regional Anesthesia

Perioperative myocardial ischemia predicts unfavorable outcomes and occurs in as many as 41% of patients with coronary artery disease or cardiac risk factors undergoing noncardiac surgery. To determine the prevalence of myocardial ischemia, we studied 52 consecutive unselected patients undergoing elective hip arthroplasty during lumbar regional anesthesia. Patients were continuously monitored for 6 days using a three-channel Holter monitor. Ninety-nine episodes of myocardial ischemia occurred in 16 patients (31%), six of whom were considered preoperatively to be at low risk for coronary artery disease. Forty-four percent of the ischemic episodes were preceded or accompanied by a heart rate greater than or equal to 100/min and 56% by a heart rate greater than or equal to 90 beats/min. Ninety-six percent of the ischemic episodes were clinically silent, and 82% were not related to patient care events. Thirteen episodes of myocardial ischemia occurred preoperatively, 1 intraoperatively, and 85 postoperatively. The incidence of postoperative ischemic episodes showed a circadian variation: 44% occurred between 6 AM and noon, 33% between noon and 6 PM, 17% between 6 PM and midnight, and 6% between midnight and 6 AM. Six adverse cardiac events occurred during hospitalization (three of the six among patients with perioperative ischemia) and an additional four events during a follow-up period of 12 months (all four events occurred among patients with perioperative ischemia). Patients with perioperative myocardial ischemia had a relative risk of 2.6 (95% confidence interval 1.3-5.2) to develop an adverse cardiac event postoperatively.

Prospective endoscopic study of stress erosions and ulcers in critically ill neurosurgical patients: current incidence and effect of acid-reducing prophylaxis

We studied prospectively 40 critically ill neurosurgical patients who required prolonged mechanical ventilation to determine the current incidence of stress-related gastroduodenal erosions and ulcers, and to assess endoscopically the efficacy of acid-reducing prophylactic treatment. Nineteen patients were randomized to receive ranitidine plus antacids if necessary to maintain gastric pH at greater than or equal to 4. The remaining 21 patients were given no drug prophylaxis. Gastric pH was significantly (p less than .001) higher in the treated group: 78% of pH readings were at greater than or equal to 4 as compared to 32% in the control group. However, after five study days, incidence and severity of stress lesions were similar in the two groups: nine patients in each group had more than five erosions, one treated patient had a gastric ulcer, and one control patient had duodenal ulcerations. No patient experienced clinically relevant upper GI bleeding. The lack of severe stress bleeding and the low ulcer rate contrast with results from earlier reports on similar patient populations. Furthermore, drug prophylaxis had no detectable benefit, as assessed endoscopically. These findings suggest that routine stress lesion prophylaxis may not be necessary in critically ill patients with comparable risk factors.

Cardiac arrest and blood ionized calcium levels.

Blood ionized and total calcium levels, and pH values were obtained in 12 patients who were being ventilated and given external cardiac massage after having had an out-of-hospital cardiac arrest. On admission they had marked ionized hypocalcemia, with mean ionized calcium levels of 0.67 +/- 0.22 mmol/L, (range, 0.26 to 0.89), but normal total calcium levels. There was a positive correlation between pH and ionized calcium levels (r = 0.71). Of the six patients who were successfully resuscitated, four were discharged and two died; the other six could not be resuscitated and died. By comparison, ionized and total calcium levels obtained within 3 minutes of cardiac arrest were normal in 9 patients who had cardiac arrests in the intensive care unit or during surgery. All were discharged. These data are the first to document the occurrence of severe ionized hypocalcemia after out-of-hospital cardiac arrest. Hypocalcemia appears to be time-dependent and due essentially to extracellular complexing of calcium. Further work is needed to determine whether patients who have out-of-hospital cardiac arrests can benefit from calcium administration.

Gastric intramucosal pH-guided therapy in patients after elective repair of infrarenal abdominal aneurysms: is it beneficial?

ObjectiveTo determine if gastric intramucosal pH (pHi)-guided therapy reduces the number of complications and length of stay in the intensive care unit (ICU) or the hospital after elective repair of infrarenal abdominal aortic aneurysms.DesignProspective, randomized study.SettingSurgical intensive care unit (SICU) of a University Hospital.PatientsFifty-five consecutive patients randomized to group 1 (pHi-guided therapy) or to group 2 (control).InterventionsPatients of group 1 with a pHi of lower than 7.32 were treated by means of a prospective protocol in order to increase their pHi to 7.32 or more.Measurements and resultspHi was determined in both groups on admission to the SICU and thereafter at 6-h intervals. In group 2, the treating physicians were blinded for the pHi values. Complications, APACHE II scores, duration of endotracheal intubation, fluid and vasoactive drug treatment, treatment with vasoactive drugs, length of stay in the SICU and in the hospital and hospital mortality were recorded. There were no differences between groups in terms of the incidence of complications. We found no differences in APACHE II scores on admission, the duration of intubation, SICU or hospital stay, or hospital mortality. In the two groups the incidence of pHi values lower than 7.32 on admission to the SICU was comparable (41 % and 42 % in groups 1 and 2, respectively). Patients with pHi lower than 7.32 had more major complications during SICU stay (p<0.05), and periods more than 10 h of persistently low pHi values (< 7.32) were associated with a higher incidence of SICU complications (p<0.01).ConclusionsLow pHi values (<7.32) and their persistence are predictors of major complications. Treatment to elevate low pHi values does not improve postoperative outcome. Based on these data, we cannot recommend the routine use of gastric tonometers for pHi-guided therapy in these patients. Further studies are warranted to determine adequate treatment of low pHi values that results in beneficial effects on the patient’s postoperative course and outcome.

Human factors and safety in emergency medicine

A model based on an input process and outcome conceptualisation is suggested to address safety-relevant factors in emergency medicine. As shown in other dynamic and demanding environments, human factors play a decisive role in attaining high quality service. Attitudes held by health-care providers, organisational shells and work-cultural parameters determine communication, conflict resolution and workload distribution within and between teams. These factors should be taken into account to improve outcomes such as operational integrity, job satisfaction and morale.

Coronary perfusion pressure, end-tidal C02 and adrenergic agents in haemodynamic stable rats☆

Coronary perfusion pressure (CPP) determines myocardial perfusion during low flow. CPP correlates with end-tidal CO2 (PetCO2) during cardiac arrest. Recent studies have demonstrated that after adrenaline, increased CPP was associated with decreased PetCO2. Intravenous infusions (4 min, N = 10) or bolus (10 s, N = 6) of methoxamine (60 micrograms/kg), isoproterenol (10 micrograms/kg), adrenaline and noradrenaline (3 micrograms/kg) were compared with saline placebo (0.2 ml/min) during spontaneous circulation in anaesthetized Sprague-Dawley rats. Infusion and bolus of methoxamine, adrenaline and noradrenaline increased CPP between 39 and 46% above baseline. Isoproterenol decreased CPP by 67%. PetCO2 decreased by 27% after bolus and only 10% after infusion of methoxamine but increased after infusion (7%) and bolus (10%) of isoproterenol and after infusion of adrenaline (11%) and noradrenaline (17%). Equipressor bolus of methoxamine, adrenaline and noradrenaline reduced PetCO2 between 10 and 27%. Bolus application induced more alpha-effects and drug infusion more beta-effects in the pulmonary vasculature. Thus, changes in pulmonary vascular resistance and associated increases in dead space were responsible for differences in PetCO2. Alpha-effects increased CPP, decreased P(et)CO2 and conversely, beta-effects decreased CPP but increased PetCO2 indicating caution when P(et)CO2 is used as non-invasive monitor of perfusion, especially after alpha-adrenergic agents.

Three cases of blunt chest trauma caused by constant compression mechanisms

Three patients (survivors) with isolated blunt chest traumas caused by constant compression mechanisms with known forces are reported on. The low velocity but high compression forces of the accidents, the effect on ventilation and oxygenation, specific early management and follow-up, clinical signs, and underlying complications of these patients are described and discussed.