Hypotensive Resuscitation and Mortality

Dr. Dong

Hypotensive Resuscitation during Active Hemorrhage: Impact on In-Hospital Mortality

Dutton MD, Mackenzie MD, Scalea MD

J Trauma 2005

This article focuses on the latest strategies to improve the outcomes of patients suffering from acute hemorrhagic shock as a result of trauma. It aims to support findings from a study done in the early 1990’s from Houston which proposed the idea of holding intravenous crystalloids and allowing permissive hypotension until the active source of bleeding is located and resolved. However the authors at the University of Maryland Shock Trauma Center noted multiple shortcomings from the previous study and embarked on a mission to re-create the aforementioned trend. 110 patients were reenrolled over 20 months, in which 55 were placed in a group with an average SBP being 114mmHg and the other 100mmHg. Variables such as injury severity score, and duration of hemorrhage were similar between the groups. In the end however, both groups demonstrated similar outcomes in which survivability was 92.7% in each group with 4 deaths each. The article mentions that the possible reasons for the lack of differentiation could have been improvements in the overall diagnostic and theurapeutic technology, short duration of the study, major difference in the mechanism of trauma and the imprecision of manual SBP readings. 

Nighttime intensivist staffing and mortality

Dr. Chang

Wallace DJ, Angus DC et al. Nighttime intensivist staffing and mortality among critically ill patients. NEJM 366; 2093: 2012.

Summary: 

There has been an increasingly hot debate regarding the degree to which nighttime intensivists are associated with improvements in the quality of ICU care. Proponents suggest nighttime intensivists provide earlier establishment of treatment plans, more timely resuscitation of unstable patients, and more consistent decision-making all hours of the day. Opponents feel intensivists at night contribute to a high cost of hospitals' investments and that most judgment is based on lack of concrete evidence. Two prior studies showed: benefit of nighttime staffing involved in ICU care with low-intensity daytime staffing (Lancet, 2000); and no reduction for in-hospital mortality after adding night intensivists to already high-intensity staffing.

In brief, the study in this article was conducted over 2009-2010 and designed surveys were sent out to clinical coordinators at sites that utilize the APACHE scoring system. The primary outcome variable was in-hospital mortality (excluded patient discharged to hospice care). Multiple statistical analyses were performed, which included multivariate models to assess a relationship between nighttime intensivist staffing and in-hospital mortality. Adjustments were made for daytime intensivist staffing, illness severity, and case mix. Results were based on 65,752 (66% of total ICU admission) admitted to 49 ICUs in 25 hospitals:

- LOW-intensity daytime staffing: nighttime staffing associated with reduction in risk-adjusted in-hospital mortality (P=0.04)

- HIGH-intensity daytime staffing: no benefit with respect to risk-adjusted in-hospital mortality (P=0.78)

The discussion suggests that nighttime intensivists are more accessible to nursing staff and other providers, which ultimately aims to reduce medical errors. This is especially applicable in the setting of sepsis where studies have shown that rapid assessment improves outcomes. Limitations discussed included: lack of a random sample, definition of ‘nighttime’ broad in that it did not measure individualized clinical behavior, and that it did not evaluate increasing role of ICU telemedicine. In concluded that a general endorsement of 24-hour intensivist coverage is premature.

Post-op Prolonged QT in Non-Cardiac Surgery

Dr. C. Chon

Postoperative QT Interval Prolongation in Patients Undergoing Noncardiac Surgery under General Anesthesia

Nagele, Peter, et al. Anesthesiology. August 2012 – Vol 117 – No. 2, pp 321-8

Summary:

12-lead EKG’s were performed on 469 adult patients undergoing major noncardiac surgery in the immediate preoperative period (baseline), within 30 minutes of arriving to the PACU, and on postoperative days 1 and 2. A single experienced anesthesiologist analyzed all of the EKG’s.

At the end of surgery, 51% of the patients demonstrated a prolonged QTc interval -- defined as greater than 440 ms. Moreover, 80% of study participants had significant increases in their QTc interval as compared to their preoperative baseline values. At later time points (ie, postoperative days 1 and 2), QTc intervals were unchanged from baseline. The perioperative QTc interval prolongation, then, can be attributed in large degree to medications administered in the perioperative period. Surgical stress may have also been an important contributing factor, although there was no correlation between increased heart rate and QTc prolongation.

The study found that isoflurane, methadone, ketorolac, calcium and ephedrine, in addition to the antibiotics cefoxitin, unasyn and zosyn, caused the most pronounced QTc prolongation. Surprisingly, neither ondansetron nor droperidol caued postoperative QTc prolongation.

One of the most important points discussed by the authors is the association between QTc prolongation and torsades de pointes. For each 10-ms increase in QTc interval, the risk of developing torsades de pointes increases by 5-7%. Therefore, the anesthesiologists must be ever-vigilant to catch the development of perioperative QTc interval prolongation.

Does Cricoid Pressure Make Intubation More Difficutl?

Dr. Wasson

Cricoid Pressure Does Not Increase the Rate of Failed Intubation by Direct Laryngoscopy in Adults

Anesthesiology 2005; 102:315-19

Turgeon, et al apply a double blind, randomized study conducted at the Centre Hospitalier Affilie Universitaire de Quebec, involving 830 patients > 18 years old to evaluate the effect of applying cricoid pressure (CP) during direct laryngoscopy and oral endotracheal tube placement.  Over a 7 month period, 700 patients were randomized into either a CP group and a sham CP group.  There was no difference in gender, age, ASA physical status, anthropometric characteristics, or risk factors for difficult intubation.    Additionally, the distribution of the anesthesiologists and anesthesia assistants was comparable .  The primary endpoint was the rate of failed intubation at 30 seconds; secondary endpoints included intubation time, grade of laryngoscopic views, and Intubation Difficulty Scale score.  Outcomes show similar rates of failed intubation at 30 seconds, grades of laryngoscopic view and the Intubation Difficulty Scale; while median intubation time was slightly longer in those who received CP.  Turgeon, et al conclude that CP, whether provided by trained personnel or a sham technique does not increase the rate of failed intubation.  Therefore, if CP use is indicated, one should not withhold the technique for fear of increasing the difficulty of intubation.  

Lactate/Pyruvate as a marker of tissue hypoxia

Dr. Perz

Lactate/Pyruvate Ratio as a Marker of Tissue Hypoxia in Circulatory and Septic Shock

Rimachi, R., Bruzzi de Carvahlo, F., Orellano-Jimenez, C., Cotton, F., Vincents, J.L., De Backer, D.  Anesth Intensive Care 2012; 40:427-423.

                This article described a prospective, observational study which measured arterial lactate and pyruvate concentrations within the first four hours of shock and at four hour intervals during the first 24 hours in 26 patients with septic shock and 13 patients with cardiogenic shock.    The basis for this study is based on the fact that several authors have suggested that lactate in itself may not be an accurate measure of hypoxia.  Increased blood lactate concentrations may also, especially in patients with sepsis, result from impaired clearance of lactate, inhibition of pyruvate dehydrogenase, and accelerated aerobic glycolysis due to the activation of the Na/K ATPase by catecholamines.  These authors suggest that lactate should be measured with pyruvate, to attempt to distinguish between hypoxic and non-hypoxic sources of lactate.  In anaerobic conditions, pyruvate is transformed to lactate and thus, the lactate/pyruvate (L/P) ratio increases.  So, this study attempted to use the L/P ratio to assess the contribution of hypoxic and non-hypoxic causes to hyperlactataemia.

The lactate/pyruvate ratio was measured in each of these patients, and several observations were noted.  Blood lactate values were higher at shock onset and remained higher in the non-survivors in relation to the survivors; the lactate/pyruvate ratio at shoch onset was significantly higher in the non-survivors.  All patients with cardiogenic shock had hyperlactataemia at the onset of shock and 69% had a high lactate/pyruvate ratio, and of the septic shock patients, 65% had hyperlactataemia and 76% had a high lactate/pyruvate ratio.  Eighteen percent of patients died during the first 24 hours, thirty one percent of patients died later in the ICU and fifty four percent were discharged alive from the ICU.  Ultimately, the study concluded that the L/P ratio confirms that hyperlactataemia is frequently, but not solely due to hypoxia, especially at the onset of shock.

EEG and Electromyogram and Somatic Response

Dr. Loyferman

Increases in Electroencephalogram and Electromyogram Variability Are Associated with an Increased Incidence of Intraoperative Somatic Response

Donald M. Mathews, MD*, Laura Clark, MD†, Jay Johansen, MD, PhD‡, Emilio Matute, MD, PhD§ and Chandran V. Seshagiri, Phd. Anesthesia & Analgesia April 2012 vol. 114 no. 4 759-770

The variability of the Bispectral Index (BIS), the variability of facial electromyogram power (EMG), and the Composite Variability Index (CVI) are 3 new measures of electroencephalogram and EMG variability. CVI is a single measure of the combined variability in BIS and EMG. This multicenter study included 120 patients undergoing elective, noncardiac surgery from 4 different sites. General anesthesia was maintained using propofol and remifentanil at 2 of the sites and sevoflurane and remifentanil at the 2 other sites. Propofol or sevoflurane was adjusted to maintain BIS between 45 and 60. Clinicians were blinded to CVI (v2.0) at all times, and remifentanil infusions were adjusted at the discretion of the clinician. The times of all intraoperative somatic events, defined as movement, grimacing, or eye opening, were recorded. To quantify how effectively each variable discriminated between somatic event segments and nonevent segments, the area under the receiver operating characteristic (ROC) curve for each variable was computed. Finally, BIS, EMG, CVI, and the HR range before each somatic event was observed and the earliest time before the somatic event at which each variable was characterized thus being able to discriminate between the somatic events and a specified set of nonevents.

BIS, EMG, and CVI, measures of electroencephalogram and EMG variability increased when intraoperative somatic events occurred. BIS, EMG, and CVI discriminated between 10-minute segments that contained a somatic event and those segments that did not contain an event better than changes in HR and mean arterial blood pressure. Furthermore, CVI increases before somatic events began earlier than HR changes and may provide caregivers with an early warning of potentially inadequate antinociception.

Anesthesia Training Shorts Practice Issues

Dr. Granger

McCook A. Anesthesia Training Shorts Practice Issues. Anesthesiology News 2011: 38 (6): 1, 29.

According to results of a recent survey, most anesthesiologists believe residency programs do a poor job of training doctors in the area of practice management. Many of the respondents believed that residents are inadequately trained in billing, reimbursement, liability, contracts as well as other issues involved in running a practice. Additionally, respondents agreed that lack of training in these areas are very important parts of becoming a physician.

More than 3.600 clinicians responded to the survey. Between 68-88% of respondents thought residents were inadequately exposed to billing issues, 71% said there was not enough training in insurance reimbursement and 84%  thought that training in these areas would greatly improve patient care as well as containment of healthcare costs. 50% believed that residents were however adequately exposed to quality assurance and scheduling in the operating room. Interestingly, residency program directors who responded to the survey were the least likely to say that residents were not well trained in practice management.

The goal of this survey was to help recognize these deficiencies and to encourage residency programs to help anesthesia resident’s transition from residency to practice.