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Michael J Jacka

Publications and source records attributed to Michael J Jacka.

16 recordsLinked to original sources
PubMed2006

Methemoglobinemia after transesophageal echocardiography: a life-threatening complication.

Methemoglobinemia is an uncommon cause of tissue hypoxemia that can be life-threatening if not promptly identified and treated. It can occur after exposure to an oxidizing agent from contaminated well water or from nitroglycerin, sodium nitroprusside, or certain local anesthetics. During oropharyngeal use of topical anesthetics for transesophageal echocardiography, systemic drug uptake is unpredictable and unexplained complications can ensue. Treatment of acquired methemoglobinemia may require methylene blue, as oxygen is not usually sufficient. Avoidance of the oxidizing agent, probably benzocaine in the cases presented, is prudent.

Adult↗
PubMed2005

How strong is the evidence for the use of perioperative beta blockers in non-cardiac surgery? Systematic review and meta-analysis of randomised controlled trials.

OBJECTIVE: To determine the effect of perioperative beta blocker treatment in patients having non-cardiac surgery. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Seven search strategies, including searching two bibliographic databases and hand searching seven medical journals. STUDY SELECTION AND OUTCOMES: We included randomised controlled trials that evaluated beta blocker treatment in patients having non-cardiac surgery. Perioperative outcomes within 30 days of surgery included total mortality, cardiovascular mortality, non-fatal myocardial infarction, non-fatal cardiac arrest, non-fatal stroke, congestive heart failure, hypotension needing treatment, bradycardia needing treatment, and bronchospasm. RESULTS: Twenty two trials that randomised a total of 2437 patients met the eligibility criteria. Perioperative beta blockers did not show any statistically significant beneficial effects on any of the individual outcomes and the only nominally statistically significant beneficial relative risk was 0.44 (95% confidence interval 0.20 to 0.97, 99% confidence interval 0.16 to 1.24) for the composite outcome of cardiovascular mortality, non-fatal myocardial infarction, and non-fatal cardiac arrest. Methods adapted from formal interim monitoring boundaries applied to cumulative meta-analysis showed that the evidence failed, by a considerable degree, to meet standards for forgoing additional studies. The individual safety outcomes in patients treated with perioperative beta blockers showed a relative risk for bradycardia needing treatment of 2.27 (95% CI 1.53 to 3.36, 99% CI 1.36 to 3.80) and a nominally statistically significant relative risk for hypotension needing treatment of 1.27 (95% CI 1.04 to 1.56, 99% CI 0.97 to 1.66). CONCLUSION: The evidence that perioperative beta blockers reduce major cardiovascular events is encouraging but too unreliable to allow definitive conclusions to be drawn.

Adrenergic beta-Antagonists↗
PubMed2005

Continuous renal replacement therapy improves renal recovery from acute renal failure.

BACKGROUND: Acute renal failure (ARF) occurs in up to 10% of critically ill patients, with significant associated morbidity and mortality. The optimal mode of renal replacement therapy (RRT) remains controversial. This retrospective study compared continuous renal replacement therapy (CRRT) and intermittent hemodialysis (IHD) for RRT in terms of intensive care unit (ICU) and hospital mortality, and renal recovery. METHODS: We reviewed the records of all patients undergoing RRT for the treatment of ARF over a 12-month period. Patients were compared according to mode of RRT, demographics, physiologic characteristics, and outcomes of ICU and hospital mortality and renal recovery using the Chi square, Student's t test, and multiple logistic regression as appropriate. RESULTS: 116 patients with renal insufficiency underwent RRT during the study period. Of these, 93 had ARF. The severity of illness of CRRT patients was similar to that of IHD patients using APACHE II (25.1 vs 23.5, P = 0.37), but they required significantly more intensive nursing (therapeutic intervention scale 47.8 vs 37.6, P = 0.0001). Mortality was associated with lower pH at presentation (P = 0.003) and increasing age (P = 0.03). Renal recovery was significantly more frequent among patients initially treated with CRRT (21/24 vs 5/14, P = 0.0003). Further investigation to define optimal timing, dose, and duration of RRT may be beneficial. CONCLUSIONS: Although further study is needed, this study suggests that renal recovery may be better after CRRT than IHD for ARF. Mortality was not affected significantly by RRT mode.

Acute Kidney Injury↗
PubMed2004

Reversible coma: a rare presentation of spontaneous intracranial hypotension.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a well-recognized neurologic disorder that typically presents with orthostatic headaches, low cerebral spinal fluid pressures and distinct abnormalities on magnetic resonance imaging. METHODS: We present a case of a rare presentation of SIH. RESULTS: A 49-year-old man presented with a two week history of orthostatic headaches that rapidly progressed to encephalopathy and coma, requiring intubation. Neuroimaging revealed abnormalities typical of SIH; diffusely enhancing pachymeninges, subdural fluid collections, and descent of the brain. Treatment with an epidural blood patch reversed his coma within minutes. Following a second blood patch, the patient became asymptomatic. No cerebral spinal leak could be identified on magnetic resonance imaging or on a nuclear medicine technetium cerebral spinal fluid flow study. At six month follow-up, he remained symptom free. CONCLUSION: The mechanism of coma in SIH is presumed to be compression of the diencephalon from downward displacement of the brain. Although it is very unusual for patients with SIH to present with coma, it is important to recognize since the coma may be reversible with epidural blood patches.

Blood Patch, Epidural↗
PubMed2004

Survey of interventions for the prevention and treatment of acute respiratory distress syndrome.

OBJECTIVE: To determine physicians' opinions and practices related to the management of patients with acute respiratory distress syndrome. DESIGN: Cross-sectional mail survey. SETTING: Province of Ontario, Canada. PARTICIPANTS: Physicians treating patients with acute respiratory distress syndrome at university-affiliated and unaffiliated hospitals. INTERVENTIONS: We searched the literature and consulted experts to generate a list of potential interventions for acute respiratory distress syndrome. Eight intensive care unit physicians selected the most relevant, available, and controversial of these interventions for prevention (n = 5) and treatment (n = 30). Fourteen physicians reviewed the questionnaire before administration to ensure clarity, realism, and clinical sensibility. We asked participants to report their views on a) the efficacy of each intervention; b) published research evaluating efficacy; c) the frequency with which they use each intervention; and d) determinants of utilization. MEASUREMENTS AND MAIN RESULTS: One hundred ten of 194 eligible physicians responded. Respondents varied considerably in their reported use of the 35 interventions. Although physicians cited published research findings as the most powerful determinant of prescribing these interventions, they were unaware of many relevant trials. Physicians also commonly cited "usual local practice" as a determinant of use, although formal practice guidelines were rarely in operation. Other variables directly associated with use of these interventions included increasing frequency of exposure to acute respiratory distress syndrome (p <.0001), increasing size of the intensive care unit in which physicians work (p =.004), and the presence of residents in the intensive care unit (p =.02). CONCLUSIONS: Wide variation in the management of acute respiratory distress syndrome appears related to limited awareness of relevant research, conflicting interpretations of research findings, and adherence to varying local practice patterns. Given physicians' desire to tailor their practice to research findings and to practice in a manner that is consistent with their local intensive care unit colleagues, future research and educational efforts related to evidence-based protocols for the management of patients with acute respiratory distress syndrome might be worthwhile.

Adult↗
PubMed2004

Cohort study of intraventricular thrombolysis with recombinant tissue plasminogen activator for aneurysmal intraventricular hemorrhage.

OBJECTIVE: Thrombolytic agents have been administered through external ventricular drains to treat intraventricular hemorrhage, the goals being to accelerate clot clearance, prevent catheter obstruction, and help control intracranial pressure. We compared these variables in a group of aneurysm patients treated by one surgeon who routinely used intraventricular recombinant tissue plasminogen activator (rt-PA) for obstructive hematocephalus with those in a group of similar patients treated by other surgeons who did not. METHODS: Patients included in this analysis were those with repaired cerebral aneurysms causing hemorrhage into at least three ventricles with ventriculomegaly requiring external ventricular drainage. The ventricular system was considered "opened" when all ventricles were patent and reduced in size on computed tomographic scans. Those treated with rt-PA received 4 mg/d through a ventricular drain until ventricular opening. RESULTS: The mean number of days to ventricular opening was 3.9 (standard deviation [SD], 1.0) for the 21 patients treated with rt-PA and 7.1 (SD, 3.7) for the 9 who were not (P = 0.001), and the mean intracranial pressure (mm Hg) 24 hours after treatment with rt-PA was 10.4 (SD, 6.1) compared with 14.1 (SD, 5.9) during the same interval for the group that did not receive rt-PA (P = 0.13). Ventricular catheter replacement was required in 1 rt-PA patient (for a misplaced catheter, before rt-PA treatment) and 3 patients who did not receive rt-PA (all for catheter obstructions with blood clot) (P = 0.07), and ventriculoperitoneal shunts were placed in 4 rt-PA patients and 3 patients who did not receive rt-PA (P = 0.4). CONCLUSION: Intraventricular thrombolysis with rt-PA seems to assist in the acute management of patients with large aneurysmal intraventricular hemorrhages, speeding clearance of aneurysmal intraventricular hemorrhage, normalizing intracranial pressure, and reducing ventricular catheter obstruction. A randomized trial is needed to confirm these findings, establish treatment safety, and determine whether treatment affects outcome.

Adult↗
PubMed2002

The appropriateness of the pulmonary artery catheter in cardiovascular surgery.

PURPOSE: The pulmonary artery catheter (PAC) is commonly used in anesthesiology and critical care, but its appropriate (where benefit exceeds risk) application is unknown. This study describes current clinical practice attitudes among anesthesiologists in cardiac and vascular surgery in an effort to determine the most appropriate indications for use of the PAC. METHODS: Anonymous, cross-sectional, mailed survey of anesthesiologists in Canada and the USA. Opinions of anesthesiologists about the appropriateness of PAC application were assessed in 36 clinical scenarios, using a nine-point Likert scale. The RAND method was adapted to identify appropriate, inappropriate, and uncertain indications for PAC application. RESULTS: Seventy-seven percent of 345 anesthesiologists responded. They agreed strongly (87%) that use of the PAC is appropriate in patients with severe ventricular impairment and unstable angina. Agreement was also present with ventricular impairment (74%) or unstable angina (55%) alone, but was less strong. A majority (53%) rated the PAC as not appropriate in the routine patient without complicating risk factors. Those who used the PAC more frequently, who had a greater practice volume, and who practised in Canada rated PAC use to be more appropriate in more scenarios. Those who did more continuing medical education rated PAC use to be less appropriate. CONCLUSIONS: While the ideal evaluation of the PAC in clinical practice would be a randomized controlled trial, such an undertaking is time-consuming, expensive, of limited generalizability, and requires clinical equipoise. This study found strong agreement that PAC application is appropriate in some patient scenarios, and agreement that it is inappropriate in others. Description of current practice using this method may identify scenarios where randomized evaluation of the PAC, or other technologies, is likely unnecessary, and others where it is highly likely to be highly beneficial.

Anesthesia↗
PubMed2002

Ventilator-associated pneumonia. Prevention, diagnosis, and therapy.

Ventilator-associated pneumonia remains the nosocomial ICU infection of greatest concern. The authors have summarized the clinical trials that have assessed specific strategies to prevent VAP and the current controversies regarding the diagnosis and therapeutic approach to this condition. Improvements in care of patients who are at risk for or who have developed VAP will depend on the judicious application of this information for individual patients.

Humans↗
PubMed2002

Intravenous heparin for cardiopulmonary bypass is an acute vasodilator.

STUDY OBJECTIVES: To investigate the changes in hemodynamic profile during cardiopulmonary bypass, and determine the effect of intravenous (IV) heparin on serum chemistry and acid-base status. DESIGN: Prospective study. SETTING: Three Canadian hospitals. PATIENTS: 43 consecutive patients undergoing elective aortocoronary bypass. INTERVENTIONS: Anesthetic technique was standarized. Hemodynamic profile, blood gases, and serum electrolytes were measured immediately before IV heparin for cardiopulmonary bypass, and 5 minutes after. RESULTS: Mean arterial pressure (MAP) decreased by a mean of 11.2 mmHg (12.5%, p = 0.0001) in all patients, of whom 28% were treated with vasoactive drugs to restore MAP. Mean systemic vascular resistance decreased by 418 dyne sec/cm(5) (25%, p = 0.0001), and mean serum potassium increased by 0.14 meq/L (p = 0.0002). The reduction in MAP correlated strongly with the reduction in SVR (p = 0.004), but not with changes in potassium or other variables. IMPLICATIONS: Mean arterial pressure is significantly affected by IV heparin for cardiopulmonary bypass. The hemodynamic mechanism is systemic vasodilation, implying that treatment with a short-acting vasoconstrictor is appropriate, if necessary. Unlike earlier studies, the increase in serum potassium observed, although reproducible, was trivial.

Acid-Base Equilibrium↗
PubMed2002

The use of and preferences for the transesophageal echocardiogram and pulmonary artery catheter among cardiovascular anesthesiologists.

UNLABELLED: The pulmonary artery catheter (PAC), although widely used in anesthesia for cardiac and vascular surgery, remains controversial. Use of transesophageal echocardiography (TEE) by cardiovascular anesthesiologists may be a substitute or a preference compared with the PAC, but this has been incompletely investigated. An anonymous, cross-sectional survey was mailed to anesthesiologists in Canada and the United States. Anesthesiologists described their use of the PAC and TEE during cardiac and vascular surgery, along with their demographic characteristics. Two hundred sixty-five (77%) of 345 anesthesiologists responded. All had the PAC available for use, and 56% had TEE available. Only 23 (11% overall) reported having undergone echocardiography training, half of whom had completed fellowships. Both the PAC and TEE were more often used in cardiac valvular surgery (P = 0.0001) than in aortocoronary bypass or abdominal vascular surgery. Among all anesthesiologists, the PAC remained the preferred monitor in either cardiac or vascular surgery (P = 0.0001), although many indicated a preference for neither monitor. Among anesthesiologists with echocardiography training, TEE was preferred (P = 0.0004). We found that TEE was accessible to more than half of the surveyed anesthesiologists in cardiovascular surgery, but relatively few of them had completed formal training in its use. Only those with completed formal TEE training indicated a significant preference for TEE use and also used it frequently. Given the continuing controversy about the appropriate application of the PAC, concern about the appropriate application of TEE is prudent. The PAC remains the more frequently used and preferred monitor among cardiovascular anesthesiologists. IMPLICATIONS: A survey of anesthesiologists found that pulmonary artery catheter monitoring is currently more frequently used compared with transesophageal echocardiography during cardiac and vascular surgery.

Adult↗
PubMed2002

Pulmonary artery occlusion pressure estimation: how confident are anesthesiologists?

OBJECTIVE: The pulmonary artery catheter is a controversial device, and randomized evaluation of its effectiveness has been demanded. Accurate estimation of pulmonary artery occlusion pressure is important for optimal use of the pulmonary artery catheter. Anesthesiologists use the pulmonary artery catheter frequently but have not been surveyed about confidence in pulmonary artery occlusion pressure estimation. Our objective was to determine the ability of practicing cardiovascular anesthesiologists to estimate pulmonary artery occlusion pressure accurately and measure their confidence in this estimate. DESIGN: Cross-sectional survey. SETTING: All academic and community hospitals in English-speaking Eastern Canada and selected centers in Western Canada and the United States. PATIENTS: Cardiovascular anesthesiologists. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We measured agreement with expert-defined timing of pulmonary artery occlusion pressure estimation, estimation of a sample pulmonary artery occlusion pressure trace, and management of a hypothetical clinical complication (air embolism). Seventy-seven percent of 345 anesthesiologists responded. Agreement about the optimal timing of pulmonary artery occlusion pressure estimation (89%) and the management of air embolism (85%) was near expectations (expected 90%). However, the pulmonary artery occlusion pressure waveform was interpreted accurately by only 61%, whereas 28% disagreed and 11% were uncertain. Significant positive associations (p =.016) between continuing medical education items and accurate interpretation were observed. CONCLUSIONS: Estimation of a sample pulmonary artery occlusion pressure trace by practicing anesthesiologists was in only modest agreement with expert assessment and published standards. Anesthesiologists demonstrated substantially less confidence in pulmonary artery occlusion pressure estimation than in the optimal timing of pulmonary artery occlusion pressure estimation. Before the effectiveness of the pulmonary artery catheter in clinical care can be systematically assessed, efforts are needed to enhance accuracy and consistency of pulmonary artery occlusion pressure estimation.

Adult↗