[Patients in intensive care after a suicide attempt with legal drugs - risk profile and course]. / Patienten mit Intensivpflichtigen Medikamentösen Suizidversuchen - Risikoprofil und Verlauf.

Little is known about the risk profile and the further history of patients who attempted suicide by severe medicinal intoxication.All patients residing in Basel (n = 190) admitted to the intensive care unit between 01/01/1998 and 12/31/2001 because of a suicide attempt with legal drugs were investigated regarding psychopathology and sociodemographic features. Also, until the end of 2005, further suicide attempts as well as potential cases of death were followed up.All 190 patients had psychiatric disorders. Compared to the general population, female sex, single status, low educational level, unemployment and invalidity were found significantly more often. Until the end of 2005 almost half of 118 patients followed up in our outpatient department committed further suicide attempts. 28 patients died, 6 of these by suicide.These patients should preferably not be prescribed medication with a low therapeutic range and they should receive intensive follow-up care.

Intracranial pressure in patients with sepsis.

INTRODUCTION: In sepsis the brain is frequently affected although there is no infection of the CNS (septic encephalopathy). One possible cause of septic encephalopathy is failure of the blood-brain barrier. Brain edema has been documented in animal models of sepsis. Aggressive fluid resuscitation in the early course of sepsis improves survival and is standard practice. We hypothesized that aggressive fluid administration will increase intracranial pressure (ICP) and may cause critical reductions in cerebral perfusion pressure (CPP). MATERIALS AND METHODS: Patients with sepsis were investigated daily on up to four consecutive days in the intensive care unit. Mean arterial blood pressure (MAP) and blood flow velocity in the middle cerebral artery were monitored for one hour each day. ICP was calculated non-invasively from MAP and flow velocity data. S-100beta was determined daily. FINDINGS: Fifty-two measurements were performed in 16 patients. ICP could be determined in 45 measurements in 15 patients. Seven patients had an ICP > 15 mmHg and 11 patients had a CPP < 60 mmHg on at least 1 day. We found no significant correlation between ICP and fluid administration, but low CPP was significantly correlated with elevated S-100beta (r = -0.47, p = 0.001). CONCLUSIONS: Further research is needed to determine the role of ICP/CPP monitoring in patients with sepsis.

Unnecessary interruptions of cardiac massage during simulated cardiac arrests.

BACKGROUND AND OBJECTIVE: Cardiopulmonary resuscitation should not be interrupted until the return of spontaneous circulation or the decision to withhold further treatment. There are no data on how consistent in-hospital cardiopulmonary resuscitation is performed. Accordingly, the aim of the present study was to identify length and type of unnecessary interruptions in simulated cardiac arrests. METHODS: The study was carried out in a patient simulator. A scenario of cardiac arrest due to ventricular fibrillation was used. Resuscitation teams consisted of three nurses, a resident and a staff physician. Using videotapes recorded during simulations, the activities of the teams were coded in 5-s intervals. Unnecessary interruptions were defined as any interruptions in cardiac massage of 10 s or more that were not caused by defibrillation or endotracheal intubation. RESULTS: Twelve teams were studied. The total time of possible cardiac massage was 414 +/- 125 s. In each team at least one unnecessary interruption occurred (range 1-5). Interruptions mounted up to 65 +/- 40 s (range 20-155) or 16 +/- 10% (range 5-41) of the total time of possible cardiac massage. Failure to swiftly resume cardiac massage after an unsuccessful defibrillation accounted for 14 of 39 episodes and for 44 +/- 40% of the time of unnecessary interruptions. The debriefings revealed that participants had generally not noticed the unnecessary interruptions during the simulation. CONCLUSIONS: The present study identified a significant amount of unnecessary interruptions in cardiac massage. These interruptions were not noticed by the health-care workers involved.

Adverse cardiac events in ICU patients with presumptive antidepressant overdose.

BACKGROUND: Antidepressants account for most poison-related admissions to intensive care units. In selected patients with confirmed cyclic antidepressant intoxication a QRS interval <0.1 s in the ECG limb leads during the first six hours excludes adverse cardiac events. However, the incidence of cardiac events and the value of ECG criteria have never been assessed prospectively on patients with presumed antidepressant overdose. AIM: To assess ingested drugs, adverse cardiac events, and ECG findings in ICU patients with a presumptive diagnosis of antidepressant overdose. METHODS: 103 consecutive patients with a presumptive diagnosis of antidepressant overdose were enrolled and prospectively followed. Outcome criteria were arrhythmias, mortality, and duration of the ICU stay. RESULTS: Mixed intoxication was identified in 66 (64%) patients. Tricyclic antidepressants were found in 88 (85%), and serotonin-reuptake inhibitors in 25 (24%) patients. Mean APACHE II score was 9.5 (SD +/- 6.0). Arrhythmias affected 15 (15%) and cardiopulmonary resuscitation was performed on 4 (4%) patients. Three patients (3%) died in the ICU. Median duration of the ICU stay was 1 day (12 hours to 6 days). Adverse cardiac events affected patients with normal and prolonged QRS interval at study entry. CONCLUSIONS: Mixed intoxication is present in most ICU patients with suspected antidepressant overdose. There is a considerable risk for adverse cardiac events, even in the presence of normal ECG recordings within the first six hours after hospital admission.

An IBM PC-based system for experimental haemodynamic studies.

An IBM PC-based real-time data acquisition, monitoring and analysis system for experimental haemodynamic studies was developed. Comprehensive haemodynamic signals, such as aortic and left ventricular pressures, aortic and coronary blood flows, two segmental lengths, two segmental thicknesses, electrocardiogram and airway pressure, were acquired and monitored to assess cardiac function. The system performs computer-aided analysis and derivations on a number of haemodynamic parameters and cardiac function indices. The system has been tested and validated extensively over a number of series of experimental haemodynamic studies to investigate the effects of anaesthetic agents, cardiovascular drugs, and changes in loading on normal and critically ischaemic myocardium of anaesthetised laboratory subjects. Without this specialised and automated system, the analysis of the data acquired from the haemodynamic studies would be too time-consuming and could not be fully performed.

Teaching the use of fiberoptic intubation in anesthetized, spontaneously breathing patients.

UNLABELLED: In patients with difficult airways, the standard of care involves fiberoptic intubation under spontaneous ventilation. However, the safety and feasibility of a fiberoptic intubation teaching program has only been documented in paralyzed and apneic patients, whereas data obtained in patients under spontaneous respiration are limited and conflicting. We evaluated 100 anesthetized patients undergoing orotracheal fiberoptic intubation. Five anesthesia residents with no prior experience in fiberoptic laryngoscopy participated in the study. In a randomized fashion, each participant tracheally intubated 10 spontaneously breathing patients (Group A: sevoflurane anesthesia via an airway endoscopy mask) and 10 paralyzed patients (Group B: total IV anesthesia with propofol, fentanyl, atracurium). Overall rate of success (96%), defined as successful intubation of the trachea within two attempts, was not different between groups. During fiberoptic intubation, Spo2 values remained >95% in Group A, whereas Spo2 decreased to <95% in two patients in Group B. Failure to pass the tube into the trachea over the bronchoscope was encountered in four patients in Group A and in no patient in Group B. Our data suggest that it is safe to teach the use of fiberoptic intubation in anesthetized, spontaneously breathing patients with normal airway anatomy. IMPLICATIONS: Fiberoptic intubation under spontaneous respiration is a well established technique for management of difficult airways. Our study demonstrates the feasibility and safety of a novice training program for fiberoptic intubation under general anesthesia, not only in paralyzed patients but also in those breathing spontaneously.

Interregional differences in the systolic and diastolic response of nonischemic myocardium to remote coronary occlusion.

BACKGROUND: Previous work showed a twofold increase in stiffness of nonischemic myocardium at the base during ischemia of the left anterior wall. Whether the diastolic response of nonischemic myocardium to remote ischemia depends on the localization of the ischemic or the nonischemic area is unknown. METHODS: In dogs with open chests, regional function in ischemic and nonischemic myocardium was assessed (sonomicrometry) before and 5 min after occlusion of the left anterior descending coronary artery (LAD; n = 7) or the left circumflex coronary artery (LCX; n = 7). RESULTS: In nonischemic myocardium at the base, left anterior descending and left circumflex coronary artery occlusion both resulted in a twofold increase in chamber stiffness, whereas contractility and peak lengthening rate remained unchanged. In nonischemic myocardium of the posterior wall, left anterior descending coronary artery occlusion resulted in a significant (P<0.05 vs. control, P<0.05 vs. base) increase (mean+/-SD) in chamber stiffness (25+/-6%), contractility (17+/-5%), and peak lengthening rate (28+/-6%). In nonischemic myocardium at the apex, left circumflex coronary artery occlusion resulted in a significant (P<0.05 vs. control, P<0.05 vs. base) increase in chamber stiffness (15+/-5%), contractility (16+/-4%), and peak lengthening rate (19+/-6%). CONCLUSIONS: Stiffening of remote nonischemic myocardium occurs regardless of the localization of the ischemic and nonischemic area. The systolic and diastolic responses of nonischemic myocardium are not necessarily homogenous but may vary among different regions.

Initiating extradural analgesia during labour: comparison of three different bupivacaine concentrations used as the loading dose.

OBJECTIVE: Potential effects of extradural analgesia on the progress of labour and obstetric outcome are still a matter of concern and the focus of ongoing debates. Despite this, little attention is paid to the initiation of extradural labour analgesia. The objective of this prospective, randomized, double-blind trial was to identify the optimal of three concentrations of bupivacaine used as a loading bolus for initiating extradural analgesia during labour. METHODS: Sixty-seven full-term parturients requesting extradural analgesia received either bupivacaine 0.25% (group A), 0.125% (group B) or 0. 0625% (group C). Bupivacaine administration was titrated to achieve a pain score /=1 based on using a modified Bromage scoring scale. There were no differences in incidence of maternal hypotension, ephedrine requirements, foetal heart rate abnormalities, mode of delivery and neonatal outcome. CONCLUSIONS: Of the three concentrations used in this clinical setting, 0.125% was the most suitable concentration of plain bupivacaine to initiate extradural analgesia in labour. Using 0.25% bupivacaine increased the incidence of motor block, whereas for 0.0625% plain bupivacaine the probability to achieve adequate analgesia was unacceptably low.

Teaching the use of fiberoptic intubation for children older than two years of age.

UNLABELLED: In 144 anesthetized children aged 2-9 yrs, the safety and feasibility of orotracheal fiberoptic intubation, with and without an airway endoscopy mask, were assessed and compared with laryngoscopic intubation. Eight anesthesia residents with experience in adult fiberoptic intubation, but who were beginners in pediatric anesthesia, participated in this study. In a randomized fashion, each resident intubated 18 children (6 in each group). The time (mean +/- SD) to achieve successful intubation was different for laryngoscopic and fiberoptic intubation (34 +/- 17 s and 80 +/- 39 s, respectively; P < 0.001). The use of the airway endoscopy mask further prolonged fiberoptic intubation (167 +/- 121 s, P < 0.001). Spo2 values remained >95% in all patients during conventional laryngoscopy and fiberoptic laryngoscopy with a mask, whereas Spo2 decreased below 95% in 2 of the 48 patients during fiberoptic intubation without a mask. Both patients promptly recovered during ventilation via a face mask. We conclude that teaching the use of fiberoptic intubation in healthy, anesthetized children aged 2-9 yrs is safe and feasible. IMPLICATIONS: Fiberoptic intubation is a valuable technique of airway management. We studied the feasibility and safety of a training program that could be used for children more than 2 yrs old. This study demonstrates that fiberoptic intubation can be effectively practiced in pediatric patients without increased risk of side effects.

Effects and interactions of nitrous oxide, myocardial ischemia, and reperfusion on left ventricular diastolic function.

The effects of nitrous oxide on left ventricular diastolic function and its potential interactions with ischemia-induced diastolic dysfunction have not been described. Accordingly, we investigated the effects of nitrous oxide in ischemic and remote nonischemic myocardium during baseline, 90 min severe low-flow myocardial ischemia (systolic bulge), and reperfusion in 11 open-chest dogs. Anesthesia was maintained with fentanyl infusion (2 micrograms.kg-1.min-1), animals were ventilated with 60% nitrogen in oxygen, and hemodynamic variables were recorded prior to and after the replacement of nitrogen by 60% nitrous oxide. During baseline, nitrous oxide moderately increased chamber stiffness (+ 10%), myocardial stiffness (+33%), and unstressed length (+4%) and decreased the peak lengthening rate (-10%). Moreover, nitrous oxide decreased regional contractility during baseline (-12% at apex, -8% at base) as well as in nonischemic myocardium during myocardial ischemia (-9%) and reperfusion (-8%). However, nitrous oxide did not modify ischemia-induced systolic or diastolic dysfunction in ischemic myocardium during ischemia and reperfusion. Myocardial ischemia (+45%) and reperfusion (+57%) were associated with an increase in myocardial stiffness of nonischemic myocardium regardless of the anesthetic technique used. This study is the first to demonstrate that in addition to its well established negative inotropic effect, nitrous oxide affects regional diastolic function.

Myocardial ischemia and reperfusion are associated with an increased stiffness of remote nonischemic myocardium.

During and after an ischemic injury, maintenance and recovery of cardiac function may critically depend on remote nonischemic myocardium. Graded myocardial ischemia is associated with an approximately 50% increase in stiffness of nonischemic myocardium. We determined whether this increase in stiffness is unique to the ischemic period or persists during reperfusion. Ten anesthetized (isoflurane 1.0% vol/vol) open-chest dogs were instrumented to measure left ventricular pressure and dimensions (sonomicrometry) in ischemic and nonischemic myocardium. Regional chamber stiffness and myocardial stiffness were assessed using the end-diastolic pressure-length relationship which was modified by stepwise infusion and withdrawal of 200 mL of the animals' own blood during baseline, 45 min low flow ischemia (systolic bulge), and 60 min after the onset of reperfusion. In remote nonischemic myocardium, regional myocardial ischemia was associated with a significant (P < 0.05) increase in chamber stiffness (+44%) and myocardial stiffness (+48%). Sixty minutes after the onset of reperfusion, chamber stiffness (+54%, P < 0.05 versus baseline) and myocardial stiffness (+55%, P < 0.05 versus baseline) remained increased. Thus, the ischemia-induced increase in stiffness of remote nonischemic myocardium persists for at least 60 min after reperfusion.

Effects and interactions of myocardial ischaemia and alterations in circulating blood volume on canine left ventricular diastolic function.

We have determined the effects of alterations in preload on ischaemia-induced diastolic dysfunction in anaesthetized beagles instrumented to measure left ventricular pressure and regional dimensions. Low-flow regional ischaemia decreased peak lengthening rates in ischaemic (mean -26 (SEM 6) mm s-1, P < 0.01) and non-ischaemic (-8.6 (3.4) mm s-1, P < 0.05) myocardium. Peak lengthening rates and the time constant of iso-volumic relaxation (tau) were not affected by alterations in preload. Absolute values of tau failed to distinguish between ischaemia and control. The ischaemia-induced decrease in peak negative dP/dt was preload dependent and caused mainly by a concomitant decrease in peak left ventricular pressure. We conclude that indices derived from segmental lengthening are sensitive to ischaemia and insensitive to preload, in contrast with indices derived from left ventricular pressure. It remains to be determined if monitoring of early segmental lengthening will improve detection and assessment of perioperative myocardial ischaemia.

Intravenous sedation for retrobulbar injection and eye surgery: diazepam and/or propofol?

Principle goals of sedation for eye surgery are to provide patient comfort and to allow the patient to stay calm during both retrobulbar injection and surgery. Insufficient sedation may not prevent the patient from moving during retrobulbar injection, whereas very deep sedation may result in respiratory complications during surgery. The aim of the present study was to evaluate the effectiveness and suitability of a combination of diazepam and propofol for sedation for both application of retrobulbar block and subsequent elective eye surgery. One-hundred and fifty patients were randomly allocated to receive either diazepam, propofol or a combination of both drugs before retrobulbar injection. Tolerance of retrobulbar injection and comfort during the surgical procedure were assessed by comfort scores using a nominal analogue scale between 1 (worst possible condition) and 6 (best conceivable condition). Side effects related to sedation were recorded. The combination of diazepam and propofol resulted in the highest comfort scores for both retrobulbar block (5.3 +/- 0.3) and the surgical procedure (5.4 +/- 0.4). Diazepam alone did not produce adequate sedation for retrobulbar block (3.1 +/- 0.3), whereas comfort scores during surgery were significantly higher (5.3 +/- 0.3) compared to propofol alone (3.6 +/- 0.4). No severe side effects induced by sedation were noted in any of the study groups. The combination of diazepam and propofol proved able to provide a reliable degree of sedation with minimal side effects for both retrobulbar block and surgery. The combination was clearly superior to the sedation induced by propofol or diazepam alone.

Platelet-activating factor (PAF) does not affect diastolic function in isolated rat hearts.

Platelet-activating factor might be responsible for the alterations of diastolic function observed in different disease states and these potential effects have not been studied. The effect of incremental concentrations of platelet-activating factor (to a maximum of 200 nM) was therefore examined in isolated perfused rat heart. Platelet-activating factor decreased coronary flow rate and contractility in a dose-dependent manner. Although high-dose platelet-activating factor decreased peak -dP/dt compared to baseline, this was not significant when compared to vehicle-administered control. There were no changes in the time constant of left ventricular relaxation and the chamber stiffness constant. These results do not support a major direct role of platelet-activating factor in diastolic dysfunction.

The influence of preload on post-systolic shortening in ischaemic myocardium.

Post-systolic shortening is a wall motion abnormality defined as shortening of cardiac muscle after the end of ejection and usually regarded as a manifestation of ischaemia. This study was designed to determine whether changes in preload may alter the magnitude of ischaemia-induced post-systolic shortening. Eleven beagles were anaesthetized (halothane 0.8%) and instrumented for measurement of pressures, flows and dimensions in the apical subendocardium supplied by the left anterior descending coronary artery. Myocardial ischaemia was obtained by tightening a micrometer-controlled snare around the left anterior descending coronary artery. Post-systolic shortening, calculated as end-systolic length minus minimum length divided by end-systolic length, was measured at different levels of preload. Increasing the preload from 4 to 17 mmHg caused a significant reduction in post-systolic shortening (8.9% vs. 12.9%, P < 0.05, Student's paired t-test); post-systolic shortening was negatively correlated with coronary perfusion pressure (r = 0.35, P < 0.01) and positively correlated with systolic bulging. This study demonstrates that the amount of post-systolic shortening depends on the volume status, which therefore has to be taken into account in interpreting regional wall motion abnormalities, such as those detected by echocardiography.

Post-ischemic diastolic dysfunction.

Though a sustained post-ischemic decrease in contractile function has been clearly established, post-ischemic diastolic function has not been thoroughly investigated. Accordingly, 11 anesthetized (isoflurane 1%) open-chest beagles were instrumented to measure left ventricular pressure and dimensions (circumferential length and wall thickness) in an apicoanterior area supplied by the left anterior descending coronary artery (LAD). Pressure-dimension relations were modified by stepwise infusion and withdrawal of 200 mL of the animals' own blood during baseline, 45 minutes partial occlusion of the LAD (systolic bulging), and 60 minutes after the onset of reperfusion. Stiffness constants were derived from the end-diastolic pressure-length and stress-strain relations, respectively. Myocardial ischemia was associated with significant (P < 0.05) alterations of the following parameters of diastolic function: (1) 47% increase in end-diastolic pressure; (2) 22% decrease in peak negative dP/dt; (3) 9% increase in the time constant of isovolumic relaxation (tau); (4) postcystolic contraction; (5) 6% increase in end-diastolic length and 10% decrease in end-diastolic thickness; (6) 12% increase in unstressed length (creep) and 13% decrease in unstressed thickness; (7) 51% increase in chamber stiffness and a 63% increase in myocardial stiffness; and (8) 40% decrease in the peak lengthening rate. After 60 minutes of reperfusion, only end-diastolic pressure and tau had returned to baseline values whereas systolic shortening fraction, postsystolic contraction, and end-diastolic and unstressed dimensions had only partially recovered. No recovery occurred in peak negative dP/dt, chamber stiffness, myocardial stiffness, and peak lengthening rate. Thus, both myocardial ischemia and reperfusion are associated with complex changes in global and regional left ventricular diastolic function.