Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients... more Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients with structural brain injury, but have not been examined in cardiac arrest survivors undergoing targeted temperature management (TTM). We investigated the effect of PRO on the development of pneumonia in that population. We conducted a retrospective cohort study comparing patients treated with PRO to those not receiving PRO (no-PRO) using Northern Hypothermia Network registry data. Cardiac arrest survivors ≥18 years old with a GCS<8 at hospital admission and treated with TTM at 32-34°C were enrolled. Differences were analyzed in univariate analyses and with logistic regression models to evaluate independent associations of clinical factors with incidence of pneumonia and good functional outcome. 416 of 1240 patients (34.5%) received PRO. Groups were similar in age, gender, arrest location, initial rhythm, and time from collapse to return of spontaneous circulation. PRO patients had less pneumonia (12.6% vs. 54.9%, p<0.001) and less sepsis (1.2 vs. 5.7%, p<0.001) compared to no-PRO patients. ICU length of stay (98 vs. 100h, p=0.2) and incidence of a good functional outcome (41.1 vs. 36.6%, p=0.19) were similar between groups. Backwards stepwise logistic regression demonstrated PRO were independently associated with a lower incidence of pneumonia (OR 0.09, 95% 0.06-0.14, p<0.001) and a similar incidence of good functional outcome. Prophylactic antibiotics were associated with a reduced incidence of pneumonia but a similar rate of good functional outcome.
A variety of technologies have been developed to assist decision-making during the management of ... more A variety of technologies have been developed to assist decision-making during the management of patients with acute brain injury who require intensive care. A large body of research has been generated describing these various technologies. The Neurocritical Care Society (NCS) in collaboration with the European Society of Intensive Care Medicine (ESICM), the Society for Critical Care Medicine (SCCM), and the Latin America Brain Injury Consortium (LABIC) organized an international, multidisciplinary consensus conference to perform a systematic review of the published literature to help develop evidence-based practice recommendations on bedside physiologic monitoring. This supplement contains a Consensus Summary Statement with recommendations and individual topic reviews on physiologic processes important in the care of acute brain injury. In this article we provide the evidentiary tables for select topics including systemic hemodynamics, intracranial pressure, brain and systemic oxygenation, EEG, brain metabolism, biomarkers, processes of care and monitoring in emerging economies to provide the clinician ready access to evidence that supports recommendations about neuromonitoring.
Seminars in Respiratory and Critical Care Medicine, 2013
Optimal management of patient comfort and sedative drug therapy for intensive care unit (ICU) pat... more Optimal management of patient comfort and sedative drug therapy for intensive care unit (ICU) patients includes establishing a goal of therapy-often defined by a desired level of consciousness, with titration of medications to achieve this target. An assessment of the level of consciousness is best performed using a simple tool, such as a sedation scale that relies on observation of the patient to assign a level of conscious that ranges from alert to unarousable. Many sedation scales incorporate observation of the patient's response to stimulation, which typically escalates from simply calling the patient's name to physical stimulation. Many such tools also incorporate an assessment of the presence and intensity of agitated behavior. Implementation of sedation scales has been associated with improved outcomes, and the frequent assessment of level of consciousness using a sedation scale is strongly recommended in clinical practice guidelines. Further, selection of a sedation scale that has been demonstrated to be valid and reliable in your patient population is endorsed. Objective measures of consciousness, such as devices that use processed electroencephalography, are less well established for routine ICU management and are recommended only for selected situations.
Pharmacotherapy: Official Journal of the American College of Clinical Pharmacy, 2001
To determine the validity and reliability of the Sedation-Agitation scale (SAS) when administered... more To determine the validity and reliability of the Sedation-Agitation scale (SAS) when administered by intensive care unit (ICU) nurses with no experience in its use. Prospective, psychometric evaluation. Adult medical-cardiac ICU. Sixty patients. Sedation and agitation were observed simultaneously but independently by nurses and two investigators, and patients were rated with the SAS. The assessment of an experienced clinical nurse specialist was recorded on visual analog scales (VAS) for sedation (VAS-S) and agitation (VAS-A). The SAS scores of ICU staff nurses were compared with VAS scored by the clinical nurse specialist using Pearson correlation coefficient. The SAS correlated well with VAS-S (Spearman's p = -0.77, p<0.001). Neither SAS nor VAS-A was correlated (Spearman's p = 0.05, p>0.5), but there were few observations of agitated patients. The SAS interrater agreement was excellent between the two trained investigators (weighted K = 0.93, p<0.001) and between investigators and staff nurses (weighted K = 0.85 and 0.87, p<0.001 for both). The SAS is reliable when administered by staff nurses with no experience with it. Due to the paucity of observations of agitated patients, we were unable to determine its validity for assessing agitation.
To determine the frequency and pattern with which patients in the intensive care unit (ICU) remov... more To determine the frequency and pattern with which patients in the intensive care unit (ICU) remove medical devices on their own, and the costs associated with this problem. Prospective observational study. Two 10-bed sections of a multidisciplinary ICU in a tertiary care teaching hospital. Adults admitted to the ICU for longer than 24 hours during October 1998. None. Medical records were reviewed prospectively for the occurrence of patient-initiated device removal and the responses to those events by health care providers. Associated costs were estimated using hospital databases and Medicare physician reimbursement schedules. Annual cost estimates were calculated using 1997 admission statistics for 1211 adults in an ICU for more than 24 hours. Thirty-six patients were studied for 199 patient-days. Ten patients (28%) removed 42 devices: 88% of these events involved gastrointestinal tubes and vascular catheters. Significant agitation was documented within 2 hours before 74% of the events. Estimated cost associated with device removal was $7606, or $181/event. The estimated annual cost in this 42-bed ICU was more than $250,000. Patients commonly remove medical devices on their own, and this represents significant consumption of health care resources.
The bispectral index (BIS), a processed variable derived from the raw electroencephalogram (EEG) ... more The bispectral index (BIS), a processed variable derived from the raw electroencephalogram (EEG) used to guide sedation in the intensive care unit (ICU), has not been tested during barbiturate therapy for elevated intracranial pressure. We determined the BIS and suppression ratio (SR) values during traditional burst monitoring of the raw EEG during pentobarbital infusions. Prospective, observational cohort study. A 42-bed multidisciplinary ICU in a tertiary care medical center. Twelve consecutive patients with elevated intracranial pressure treated with pentobarbital infusions. All patients were monitored continuously with the Aspect Medical Systems A-1050 bedside EEG monitor using a bilateral referential montage. Pentobarbital doses were titrated based on the raw EEG to attain a burst-suppression pattern with a goal of 3-5 bursts/minute. Drug dosage, intracranial pressure, cerebral perfusion pressure values, EEG bursts/minute, BIS version 3.2, and SR were recorded daily. The 12 patients were monitored for 62 patient-days. Mean +/- SD age was 32 +/- 15 years, seven (58%) patients were male, mean Acute Physiology and Chronic Heath Evaluation II score was 17.0 +/- 5.0, and hospital mortality was 42%. The mean pentobarbital infusion rate was 124 +/- 49 mg/hour or 2.3 +/- 1.3 mg/kg/hour, and mean pentobarbital serum concentration was 29.7 +/- 13 microg/ml. The mean BIS value was 18 +/- 14, mean SR 56% +/- 36%; BIS correlated well with SR (r=-0.99, p<0.001). For patient-days with a burst-suppression pattern, BIS 3.2 (r=0.90, p<0.001) and SR (r=-0.89, p<0.001) strongly correlated with the number of bursts/minute. The mean BIS value corresponding to 3-5 bursts/minute was 15 (95% confidence interval [CI] 10-20); SR value was 71 (95% CI 61-80). The Aspect A-1050 applied to patients and monitored by nurses and physicians works well as a bedside EEG monitor, providing a raw EEG signal to titrate barbiturate therapy. The continuous data trend and real-time digital output for the BIS and SR quantify the degree of EEG suppression well and may prove helpful in facilitating titration of barbiturate infusions.
Effectiveness of cooling and adverse events (AEs) involving skin have not been intensively evalua... more Effectiveness of cooling and adverse events (AEs) involving skin have not been intensively evaluated in cardiac arrest survivors treated with therapeutic hypothermia (TH) when induced and maintained with a servomechanism-regulated surface cooling system. Retrospective review of sixty-nine cardiac arrest survivor-events admitted from April 2006-September 2008 who underwent TH using the Medivance Arctic Sun Temperature Management System. A TH database and medical records were reviewed, and nursing interviews conducted. Primary endpoint was time from initiation to target temperature (TT; 32-34 °C). Secondary endpoints were cooling rate, percentage of hypothermia maintenance phase at TT, effect of body-mass index (BMI) on rate of cooling, and AEs. Mean time to the target temperature (TT) was 2.78 h; 80% of patients achieved TT within 4 h; all did within 8 h. Patients were at TT for 96.7% of hypothermia maintenance; 17% of patients had >1 hourly temperature measurement outside TT range. Mean cooling rate during induction phase was 1.1 °C/h, and was not associated with BMI. Minor skin injury occurred in 14 (20%) patients; 4 (6%) were device-related. Skin injuries were associated with shock (P = 0.04), and decubitus ulcers were associated with left ventricular ejection fraction <45% (P = 0.004). AEs included shivering (94%), hypokalemia (81%), hyperglycemia (57%), pneumonia (23%), bleeding (22%), post-cooling fever (17%), and bacteremia (9%). The Arctic Sun Temperature Management System was an effective means of performing therapeutic hypothermia after cardiac arrest. Infrequent skin injuries were associated with vasopressor use and low ejection fraction.
The metabolism of haloperidol (HP) to the potentially neurotoxic pyridinium species, HPP+ and RHP... more The metabolism of haloperidol (HP) to the potentially neurotoxic pyridinium species, HPP+ and RHPP+, has been demonstrated in humans. In vitro studies in microsomes harvested from various animal species indicate that the tetrahydropyridines, HPTP and RHPTP, could be intermediates in this pathway. However, this has not yet been demonstrated in vivo in humans. In this study, plasma and urine collected from eight critically ill patients treated with high doses of intravenous HP were analyzed for HPTP and RHPTP using HPLC with electrochemical detection. However, neither HPTP nor RHPTP were detected despite plasma concentrations of HP and RHP higher than any previously reported. HPP+ and RHPP+ were both present in the urine in high concentrations and accounted for 1.1 +/- 0.5% and 5.3 +/- 3.6%, respectively, of the administered dose of HP. The apparent elimination half-lives of HPP+ and RHPP+ were 67.3 +/- 11.0 hr and 63.3 +/- 11.6 hr, respectively. The absence of HPTP and RHPTP in plasma and urine suggests that in humans these tetrahydropyridines either are insignificant intermediates in the metabolism of HP in vivo or are present only transiently at their site of formation and are not released into the circulation.
Methemoglobinemia is a rare but potentially serious complication occurring after the administrati... more Methemoglobinemia is a rare but potentially serious complication occurring after the administration of the anesthetic agent benzocaine. We describe the findings and subsequent treatment of a patient who developed this complication after the use of benzocaine during the course of transesophageal echocardiography.
Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients... more Prophylactic antibiotics (PRO) reduce the incidence of early-onset pneumonia in comatose patients with structural brain injury, but have not been examined in cardiac arrest survivors undergoing targeted temperature management (TTM). We investigated the effect of PRO on the development of pneumonia in that population. We conducted a retrospective cohort study comparing patients treated with PRO to those not receiving PRO (no-PRO) using Northern Hypothermia Network registry data. Cardiac arrest survivors ≥18 years old with a GCS<8 at hospital admission and treated with TTM at 32-34°C were enrolled. Differences were analyzed in univariate analyses and with logistic regression models to evaluate independent associations of clinical factors with incidence of pneumonia and good functional outcome. 416 of 1240 patients (34.5%) received PRO. Groups were similar in age, gender, arrest location, initial rhythm, and time from collapse to return of spontaneous circulation. PRO patients had less pneumonia (12.6% vs. 54.9%, p<0.001) and less sepsis (1.2 vs. 5.7%, p<0.001) compared to no-PRO patients. ICU length of stay (98 vs. 100h, p=0.2) and incidence of a good functional outcome (41.1 vs. 36.6%, p=0.19) were similar between groups. Backwards stepwise logistic regression demonstrated PRO were independently associated with a lower incidence of pneumonia (OR 0.09, 95% 0.06-0.14, p<0.001) and a similar incidence of good functional outcome. Prophylactic antibiotics were associated with a reduced incidence of pneumonia but a similar rate of good functional outcome.
A variety of technologies have been developed to assist decision-making during the management of ... more A variety of technologies have been developed to assist decision-making during the management of patients with acute brain injury who require intensive care. A large body of research has been generated describing these various technologies. The Neurocritical Care Society (NCS) in collaboration with the European Society of Intensive Care Medicine (ESICM), the Society for Critical Care Medicine (SCCM), and the Latin America Brain Injury Consortium (LABIC) organized an international, multidisciplinary consensus conference to perform a systematic review of the published literature to help develop evidence-based practice recommendations on bedside physiologic monitoring. This supplement contains a Consensus Summary Statement with recommendations and individual topic reviews on physiologic processes important in the care of acute brain injury. In this article we provide the evidentiary tables for select topics including systemic hemodynamics, intracranial pressure, brain and systemic oxygenation, EEG, brain metabolism, biomarkers, processes of care and monitoring in emerging economies to provide the clinician ready access to evidence that supports recommendations about neuromonitoring.
Seminars in Respiratory and Critical Care Medicine, 2013
Optimal management of patient comfort and sedative drug therapy for intensive care unit (ICU) pat... more Optimal management of patient comfort and sedative drug therapy for intensive care unit (ICU) patients includes establishing a goal of therapy-often defined by a desired level of consciousness, with titration of medications to achieve this target. An assessment of the level of consciousness is best performed using a simple tool, such as a sedation scale that relies on observation of the patient to assign a level of conscious that ranges from alert to unarousable. Many sedation scales incorporate observation of the patient's response to stimulation, which typically escalates from simply calling the patient's name to physical stimulation. Many such tools also incorporate an assessment of the presence and intensity of agitated behavior. Implementation of sedation scales has been associated with improved outcomes, and the frequent assessment of level of consciousness using a sedation scale is strongly recommended in clinical practice guidelines. Further, selection of a sedation scale that has been demonstrated to be valid and reliable in your patient population is endorsed. Objective measures of consciousness, such as devices that use processed electroencephalography, are less well established for routine ICU management and are recommended only for selected situations.
Pharmacotherapy: Official Journal of the American College of Clinical Pharmacy, 2001
To determine the validity and reliability of the Sedation-Agitation scale (SAS) when administered... more To determine the validity and reliability of the Sedation-Agitation scale (SAS) when administered by intensive care unit (ICU) nurses with no experience in its use. Prospective, psychometric evaluation. Adult medical-cardiac ICU. Sixty patients. Sedation and agitation were observed simultaneously but independently by nurses and two investigators, and patients were rated with the SAS. The assessment of an experienced clinical nurse specialist was recorded on visual analog scales (VAS) for sedation (VAS-S) and agitation (VAS-A). The SAS scores of ICU staff nurses were compared with VAS scored by the clinical nurse specialist using Pearson correlation coefficient. The SAS correlated well with VAS-S (Spearman's p = -0.77, p<0.001). Neither SAS nor VAS-A was correlated (Spearman's p = 0.05, p>0.5), but there were few observations of agitated patients. The SAS interrater agreement was excellent between the two trained investigators (weighted K = 0.93, p<0.001) and between investigators and staff nurses (weighted K = 0.85 and 0.87, p<0.001 for both). The SAS is reliable when administered by staff nurses with no experience with it. Due to the paucity of observations of agitated patients, we were unable to determine its validity for assessing agitation.
To determine the frequency and pattern with which patients in the intensive care unit (ICU) remov... more To determine the frequency and pattern with which patients in the intensive care unit (ICU) remove medical devices on their own, and the costs associated with this problem. Prospective observational study. Two 10-bed sections of a multidisciplinary ICU in a tertiary care teaching hospital. Adults admitted to the ICU for longer than 24 hours during October 1998. None. Medical records were reviewed prospectively for the occurrence of patient-initiated device removal and the responses to those events by health care providers. Associated costs were estimated using hospital databases and Medicare physician reimbursement schedules. Annual cost estimates were calculated using 1997 admission statistics for 1211 adults in an ICU for more than 24 hours. Thirty-six patients were studied for 199 patient-days. Ten patients (28%) removed 42 devices: 88% of these events involved gastrointestinal tubes and vascular catheters. Significant agitation was documented within 2 hours before 74% of the events. Estimated cost associated with device removal was $7606, or $181/event. The estimated annual cost in this 42-bed ICU was more than $250,000. Patients commonly remove medical devices on their own, and this represents significant consumption of health care resources.
The bispectral index (BIS), a processed variable derived from the raw electroencephalogram (EEG) ... more The bispectral index (BIS), a processed variable derived from the raw electroencephalogram (EEG) used to guide sedation in the intensive care unit (ICU), has not been tested during barbiturate therapy for elevated intracranial pressure. We determined the BIS and suppression ratio (SR) values during traditional burst monitoring of the raw EEG during pentobarbital infusions. Prospective, observational cohort study. A 42-bed multidisciplinary ICU in a tertiary care medical center. Twelve consecutive patients with elevated intracranial pressure treated with pentobarbital infusions. All patients were monitored continuously with the Aspect Medical Systems A-1050 bedside EEG monitor using a bilateral referential montage. Pentobarbital doses were titrated based on the raw EEG to attain a burst-suppression pattern with a goal of 3-5 bursts/minute. Drug dosage, intracranial pressure, cerebral perfusion pressure values, EEG bursts/minute, BIS version 3.2, and SR were recorded daily. The 12 patients were monitored for 62 patient-days. Mean +/- SD age was 32 +/- 15 years, seven (58%) patients were male, mean Acute Physiology and Chronic Heath Evaluation II score was 17.0 +/- 5.0, and hospital mortality was 42%. The mean pentobarbital infusion rate was 124 +/- 49 mg/hour or 2.3 +/- 1.3 mg/kg/hour, and mean pentobarbital serum concentration was 29.7 +/- 13 microg/ml. The mean BIS value was 18 +/- 14, mean SR 56% +/- 36%; BIS correlated well with SR (r=-0.99, p<0.001). For patient-days with a burst-suppression pattern, BIS 3.2 (r=0.90, p<0.001) and SR (r=-0.89, p<0.001) strongly correlated with the number of bursts/minute. The mean BIS value corresponding to 3-5 bursts/minute was 15 (95% confidence interval [CI] 10-20); SR value was 71 (95% CI 61-80). The Aspect A-1050 applied to patients and monitored by nurses and physicians works well as a bedside EEG monitor, providing a raw EEG signal to titrate barbiturate therapy. The continuous data trend and real-time digital output for the BIS and SR quantify the degree of EEG suppression well and may prove helpful in facilitating titration of barbiturate infusions.
Effectiveness of cooling and adverse events (AEs) involving skin have not been intensively evalua... more Effectiveness of cooling and adverse events (AEs) involving skin have not been intensively evaluated in cardiac arrest survivors treated with therapeutic hypothermia (TH) when induced and maintained with a servomechanism-regulated surface cooling system. Retrospective review of sixty-nine cardiac arrest survivor-events admitted from April 2006-September 2008 who underwent TH using the Medivance Arctic Sun Temperature Management System. A TH database and medical records were reviewed, and nursing interviews conducted. Primary endpoint was time from initiation to target temperature (TT; 32-34 °C). Secondary endpoints were cooling rate, percentage of hypothermia maintenance phase at TT, effect of body-mass index (BMI) on rate of cooling, and AEs. Mean time to the target temperature (TT) was 2.78 h; 80% of patients achieved TT within 4 h; all did within 8 h. Patients were at TT for 96.7% of hypothermia maintenance; 17% of patients had >1 hourly temperature measurement outside TT range. Mean cooling rate during induction phase was 1.1 °C/h, and was not associated with BMI. Minor skin injury occurred in 14 (20%) patients; 4 (6%) were device-related. Skin injuries were associated with shock (P = 0.04), and decubitus ulcers were associated with left ventricular ejection fraction <45% (P = 0.004). AEs included shivering (94%), hypokalemia (81%), hyperglycemia (57%), pneumonia (23%), bleeding (22%), post-cooling fever (17%), and bacteremia (9%). The Arctic Sun Temperature Management System was an effective means of performing therapeutic hypothermia after cardiac arrest. Infrequent skin injuries were associated with vasopressor use and low ejection fraction.
The metabolism of haloperidol (HP) to the potentially neurotoxic pyridinium species, HPP+ and RHP... more The metabolism of haloperidol (HP) to the potentially neurotoxic pyridinium species, HPP+ and RHPP+, has been demonstrated in humans. In vitro studies in microsomes harvested from various animal species indicate that the tetrahydropyridines, HPTP and RHPTP, could be intermediates in this pathway. However, this has not yet been demonstrated in vivo in humans. In this study, plasma and urine collected from eight critically ill patients treated with high doses of intravenous HP were analyzed for HPTP and RHPTP using HPLC with electrochemical detection. However, neither HPTP nor RHPTP were detected despite plasma concentrations of HP and RHP higher than any previously reported. HPP+ and RHPP+ were both present in the urine in high concentrations and accounted for 1.1 +/- 0.5% and 5.3 +/- 3.6%, respectively, of the administered dose of HP. The apparent elimination half-lives of HPP+ and RHPP+ were 67.3 +/- 11.0 hr and 63.3 +/- 11.6 hr, respectively. The absence of HPTP and RHPTP in plasma and urine suggests that in humans these tetrahydropyridines either are insignificant intermediates in the metabolism of HP in vivo or are present only transiently at their site of formation and are not released into the circulation.
Methemoglobinemia is a rare but potentially serious complication occurring after the administrati... more Methemoglobinemia is a rare but potentially serious complication occurring after the administration of the anesthetic agent benzocaine. We describe the findings and subsequent treatment of a patient who developed this complication after the use of benzocaine during the course of transesophageal echocardiography.
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Papers by Richard Riker