Saturday, January 12, 2013

The Cochrane Review regarding anesthetic technique for Cesarean Section.

Regional anaesthesia (spinal or epidural anaesthesia) for caesarean section is the preferred option when balancing risks and benefits to the mother and her fetus. Spinal anaesthesia for caesarean section is thought to be advantageous due to simplicity of technique, rapid administration and onset of anaesthesia, reduced risk of systemic toxicity and increased density of spinal anaesthetic block.In a Cochrane review titled spinal versus epidural anaesthesia for caesarean section which was done by Ng KW, Parsons J, Cyna AM, Middleton P and published on April 18, 2012,the authors have reviewed the trials that assess the relative efficacy and side-effects of spinal versus epidural anesthesia in women having caesarean section. A total of ten trials which included 751 women were reviewed.The reviewers found no difference between spinal and epidural techniques with regards to failure rate, need for additional intraoperative analgesia, need for conversion to general anesthesia intraoperatively, maternal satisfaction, need for postoperative pain relief and neonatal intervention. Women receiving spinal anaesthesia for caesarean section showed reduced time from start of the anaesthetic to start of the operation but increased need for treatment of hypotension.They conclude that both spinal and epidural techniques are shown to provide effective anaesthesia for caesarean section. Both techniques are associated with moderate degrees of maternal satisfaction. Spinal anaesthesia has a shorter onset time, but treatment for hypotension is more likely if spinal anesthesia is used.

There is a recently published Cochrane review which compares the effects of regional anesthesia with those of general anesthesia on the outcomes of CS.the reviewers were Afolabi BB and Lesi FEA and it was published on October 17, 2012.Regional anaesthesia (RA) and general anaesthesia (GA) are commonly used for caesarean section (CS) and both have advantages and disadvantages. It is important to clarify what type of anaesthesia is more efficacious.Twenty-two out of 29 included studies (1793 women) contributed data to this review.they found that compared to women who had GA, women who had either epidural anesthesia or spinal anesthesia were found to have a significantly lower difference between pre and postoperative hematocrit. Compared with GA, women having either an epidural anesthesia or spinal anesthesia had a lower estimated maternal blood loss. There was evidence of a significant difference in terms of satisfaction with anesthetic technique - compared with the epidural or spinal group, more women in the GA group stated they would use the same technique again if they needed CS for a subsequent pregnancy.No significant difference was seen in terms of neonatal Apgar scores of six or less and of four or less at five minutes and the need for neonatal resuscitation with oxygen.They conclude that there is no evidence from this review to show that RA is superior to GA in terms of major maternal or neonatal outcomes.

What I have known from textbooks, though!!!

As Chestnut says, overall, neuraxial (epidural, spinal, CSE) techniques are the preferred method of providing anesthesia for cesarean delivery. In an analysis of obstetric anesthesia trends in the United States between 1981 and 2001, a progressive increase was noted in the use of neuraxial anesthesia, especially spinal anesthesia, for both elective and emergency cesarean deliveries.Neuraxial anesthesia has been used for more than 80% of cesarean deliveries since 1992. Similar increases have occurred in the United Kingdom and in other developed as well as developing countries.(ref- Shibli KU, Russell IF. A survey of anaesthetic techniques used for caesarean section in the UK in 1997. Int J Obstet Anesth 2000; 9:160-7).

Do the general anesthesia techniques increase the maternal mortality and morbidity?

Maternal mortality following general anesthesia has been a primary motivator for the transition toward greater use of neuraxial anesthesia for cesarean delivery.The estimated case-fatality risk ratio for general versus neuraxial anesthesia was as high as 16.7 in the years 1985 to 1990; however, a similar analysis by the same group of investigators observed a nonsignificant risk ratio of 1.7 in the years 1991 to 2002.These data may overstate the relative risk of general anesthesia, because this form of anesthesia is used principally when neuraxial anesthetic techniques are contraindicated for medical reasons or time constraints.

And what about the child?
Differences in neonatal outcomes among different anesthetic techniques are not as clear. Apgar and neonatal neurobehavioral scores are relatively insensitive measures of neonatal well-being, and umbilical cord blood gas and pH measurements may reflect the reason for the cesarean deliv- ery rather than differences in anesthetic techniques’ effect on fetal well-being.





Friday, November 16, 2012

How to control pain and sedate mechanically ventilated-patients : A review from AJRCCM



Untreated pain equates to unnecessary suffering, and treating pain prevents agitation and delirium in mechanically ventilated patients. Thus, ensuring good pain control is of paramount importance. The problem is figuring out who is in pain, when most patients can’t communicate. Many physicians treat all intubated patients for pain with an opioid infusion, but pain is only present in 40% of the severely critically ill during their ICU stays, some studies show, and excessive opioids can prolong mechanical ventilation and ICU stays.

Kress & Patel recommend using validated tools such as the Numeric Rating Scale, for patients who can at least point, and the Behavioral Pain Scale, the Critical Care Pain Observation Tool or the Nonverbal Pain Scale for patients who can’t communicate. These tools are each limited and flawed, but have been validated in some contexts and are better than not formally assessing pain.

Anecodtal analgesic strategies also include:

When a patient is believed to be in pain, use high bolus doses of opioids preferentially to achieve analgesia (e.g., repeated doses of 100 mcg of fentanyl), while making only small increases (e.g., < 25%) in the basal infusion rate as infrequently as possible.
Check the infusion rate on your patient every morning, and after the patient returns from procedures, to see if other professionals have increased the basal infusion rate to reduce movement or agitation. Reduce the opioid continuous infusion rate as much as possible on a daily basis, preferably as part of a sedation interruption protocol.

Sedation in Mechanically Ventilated Patients

Avoid sedation agents and their side effects entirely if possible; analgesics (e.g. fentanyl) may be sufficient to ensure comfort, especially if pain is causing the observed agitation.

BENZODIAZEPINES

Benzodiazepines midazolam and lorazepam are the most commonly used sedatives, likely due to their lower per-unit cost, although in randomized trials benzodiazepines result in longer time to extubation and discharge, potentially increasing costs overall.
Benzos are lipophilic and accumulate in fat, prolonging sedation in obese patients after continuous infusions. Midazolam’s active metabolites are renally cleared and accumulate during kidney failure, prolonging sedation. Lorazepam is preferred for patients with impaired renal function; its metabolites are not active.
Lorazepam is as effective at achieving sedation and is more cost effective than midazolam, according to one randomized trial.

Benzodiazepines suppress respiratory drive, in a shallow-breathing pattern (as opposed to the “deep and slow” respiratory depression from opioids). Benzodiazepines are believed to frequently cause delirium when used for patients in the ICU, especially elderly patients, although the measured association is actually quite weak.

PROPOFOL

Propofol reduces time to extubation compared to benzodiazepines, according to multiple randomized trials.
Propofol causes hypotension especially with bolus dosing, but authors argue the effect is minimal in volume-resuscitated patients.
Monitor triglycerides 1-2 times / week and include the 1.1 kcal/mL in the nutrition plan while a patient is receiving a lipid-rich propofol infusion.
Propofol infusion syndrome (cardiac failure from sudden bradycardia, metabolic acidosis, hyperkalemia, rhabdomyolysis) appears quite rare in adults receiving usual doses (4-5 mg/kg/hr or less); consider checking pH, lactate, creatine kinase when using propofol for long periods or at high doses.

Sedation Scales, Sedation Vacations & Strategy

The Richmond Agitation-Sedation Scale (RASS) is the most-validated and most widely-used tool to assess depth of sedation. Titrate almost all patients to a RASS score of -2 or less; very ill or agitated patients (e.g., severe ARDS) may “rarely” require RASS -3 or -4.

Interrupt sedation completely on a daily basis in all mechanically ventilated patients whenever possible (sedation vacation or sedation holiday). Restart the dose at half the previous rate, if the patient becomes agitated. As Kress et al showed, sedation holidays reduce ventilator days and length of ICU stays.

Pair the daily sedation interruption with a spontaneous breathing trial, when possible. This led to reduced ventilator days and 1 year mortality in a randomized trial (Girard, Kress et al Lancet 2008).

Daily sedation vacations don’t seem to result in psychological harm; in fact, sedation holidays may reduce the incidence of post traumatic stress disorder after critical illness.

A whole-team interdisciplinary strategy with buy-in from nursing, physical therapists, etc is required to ensure an ICU sedation strategy is applied consistently across shifts, staff, and patients. Nurses are ultimately in control of the sedation on an hour-by-hour basis (as they should be); nursing-driven protocols have reduced sedation doses and improved outcomes in numerous studies.

Delirium in the Mechanically Ventilated Patient

Delirium is common in critically ill patients, and is associated with a variety of worse outcomes (decreased respiratory and functional status, quality of life, and mortality in both the short and long term). However, it is not clear whether delirium causes poor outcomes, or is simply a marker of severe illness. It is also unclear whether interventions that treat or prevent delirium likewise improve outcomes.

For this reason, it’s likewise unclear whether devoting resources (mainly nursing) to systematically screen for delirium repeatedly on every patient is justified or beneficial. Measures like early mobilization that improve delirium also improve other outcomes like ventilator days, contaminating any potential benefit from reduction of delirium per se.

Despite the dearth of evidence, reducing delirium seems a worthy goal; authors cite modest evidence that nonpharmacologic measures (reorientation, enhancing the conditions for sleep, reducing benzodiazepines, anticholinergics, and other delirium-causing medicines) can reduce delirium outside the ICU; possibly they work for patients in the ICU as well. Early mobilization, daily sedation interruptions, and daily spontaneous breathing trials have reduced delirium in mechanically ventilated patients in randomized trials.

The best validated tool for assessing delirium, CAM-ICU, has a high specificity but had only 50% sensitivity when tested in a real-world setting. The ICDSC requires more effort and reportedly had higher sensitivity than CAM-ICU in one comparison (But what is the gold standard for validating a test for delirium in critically ill, intubated, noncommunicative patients?)

ANTIPSYCHOTICS FOR ICU DELIRIUM

Antipsychotic drugs are commonly used to treat agitation believed to be due to ICU delirium;haloperidol is probably the most often-used drug. However, Kress & Patel point out ”[t]here is no convincing evidence for the use of antipsychotics in the treatment of ICU delirium.” Simply put, no good-quality, prospective or placebo-controlled randomized trials have been done to confirm the benefit of haloperidol or other antipsychotics for ICU delirium.

Authors suggest the practice is nevertheless defensible: A retrospective study showed lower mortality in haloperidol-treated patients receiving mechanical ventilation, and a randomized trial testing Haldol against olanzapine showed reductions in delirium in both groups (neither was superior, there was no placebo arm, and 6 of 45 haloperidol-treated patients developed extrapyramidal side effects, compared to none in the olanzepine group).

Due to its tendency to prolong QT intervals and induce torsades de pointes in a tiny fraction of patients, haloperidol has carried an FDA black-box warning since 2007. A 1998 retrospective case control study (including 8 cases of TdP) suggested that critically ill patients are at risk for TdP from haloperidol. All antipsychotics can lengthen QT intervals, but haloperidol (and thioridazine and droperidol) is most strongly linked to torsades de pointes (28+ cases as of 2007). Still, the Society of Critical Care Medicine recommends haloperidol for treatment of ICU delirium, based on “level C” (the weakest).

Parting Points
Pain (requiring analgesia), agitation or anxiety (justifying sedation), and delirium (justifying antipsychotics) are often not reliably distinguishable in mechanically ventilated patients, even by experienced physicians and nurses.
The sicker the patient, the greater may be the difficulty in ascertaining the cause of distress (and, often, the higher the doses of drugs required).
Pain comes first in the “hierarchy of agitation causes,” and carries a moral imperative to treat it; always seek to dentify and treat any pain that’s present.
Continually strive to reduce pharmacotherapy to the minimum required in each class, and especially for sedating medications; evidence says this will result in shorter ICU stays, faster and fuller recoveries for critically ill patients.
Further reading:

Patel SB, Kress JP. Sedation and Analgesia in the Mechanically Ventilated Patient. Concise clinical review. Am J Respir Crit Care Med 2012;185:486-497.

Jacobi J et al. Clinical practice guidelines for the sustained use of sedatives and analgesics in the critically ill adult. Crit Care Med 2002;30:119-141.

Puntillo K et al. Evaluation of pain in ICU patients. Chest 2009;135:1069-1074.

Vanderbilt University Medical Center, icudelirium.org


Monday, September 26, 2011

One-stop shopping: federated search engines

Perhaps the simplest and most efficient answer for most clinicians search-ing for information for patient care is a federated search engine such as TRIP, Turning Research into Practice, http://www.tripdatabase.com/ or SUMsearch, http://sumsearch.uthscsa.edu/. Both sources search multiple resources simultaneously and are free. • SUMsearch, produced by the University of Texas, has an excellent search engine that facilitates a clear and focused search on a somewhat limited range of resources. One of the recommendations in the results from a SUMsearch query suggested a search of TRIP. • TRIP has a truly primitive search engine, but it searches synthesised sources (systematic reviews including Cochrane reviews), summarised sources (practice guidelines from North America, Europe, Australia/New Zealand and elsewhere, as well as electronic textbooks including the excel-lent peer-reviewed eMedicine), and pre-appraised sources (Evidence-based Medicine, Evidence-based Mental Health, etc.), as well as searching all clinical query domains in PubMed simultaneously. Moreover, searches can be limited by discipline, such as Anesthesia and Critical care, helping both to focus a search and eliminate clearly irrelevant results, and acknowledg-ing the tendency of medical specialties to prefer the literature in their own journals. Given that most clinicians favour very simple searches, failing the availability of a broad evidence-based summarising resource such as ACP PIER or DynaMed, a TRIP search would probably produce the most satis-factory results from all types of information.
Source -
How to Read a Paper: The Basics of Evidence-Based Medicine; Trisha-Greenhalgh
- Posted using BlogPress from my iPad

Location:Kathmandu

Wednesday, March 11, 2009

Maximum Surgical Blood Ordering Schedule (MSBOS)

The Maximum Surgical Blood Order Schedule (MSBOS) is a table of elective surgical procedures which lists the number of units of red cells routinely crossmatched for them pre-operatively.
It allows the more efficient use of blood stocks and reduces wastage.

further inf is available at : British Committee for Standards in Haematology Blood Transfusion Task Force (1990) Guidelines for implementation of a maximun surgical blood order schedule. Cinical and Laboratory Haematology 12: 321-327 .