J. Sudharma Ranasinghe

Cardiac Output Assessed by Invasive and Minimally Invasive Techniques

Cardiac output (CO) measurement has long been considered essential to the assessment and guidance of therapeutic decisions in critically ill patients and for patients undergoing certain high-risk surgeries. Despite controversies, complications and inherent errors in measurement, pulmonary artery catheter (PAC) continuous and intermittent bolus techniques of CO measurement continue to be the gold standard. Newer techniques provide less invasive alternatives; however, currently available monitors are unable to provide central circulation pressures or true mixed venous saturations. Esophageal Doppler and pulse contour monitors can predict fluid responsiveness and have been shown to decrease postoperative morbidity. Many minimally invasive techniques continue to suffer from decreased accuracy and reliability under periods of hemodynamic instability, and so few have reached the level of interchangeability with the PAC.

Ultrasound assessment of the vertebral level of the intercristal line in pregnancy

BACKGROUND: The intercristal line is known to most frequently cross the L4 spinous process or L4-5 interspace; however, it is speculated to be positioned higher during pregnancy because of the exaggerated lumbar lordosis. Clinical estimation of vertebral levels relying on the use of the intercristal line has been shown to often be inaccurate. We hypothesized that the vertebral level of the intercristal line determined by palpation would be higher than the level determined by ultrasound in pregnant women. METHODS: Fifty-one term pregnant patients were recruited. Two experienced anesthesiologists performed estimates of the position of the intercristal line by palpation. Using ultrasound, another anesthesiologist who was blinded to the clinical estimates, determined the position of the superior border of the iliac crest in the transverse and longitudinal planes and then identified the lumbar vertebral levels. The vertebral level at which the clinical estimates of the intercristal line crossed the spine was recorded and compared with the ultrasound-determined level of the superior border of the iliac crest. RESULTS: The clinical estimates of the spinal level of the intercristal line agreed with the ultrasound measurement 14% of the time (14 of 101; 95% confidence interval [CI]: 8%, 22%). The clinical estimates were 1 level higher than the ultrasound measurement 23% of the time (23 of 101; 95% CI: 16%, 32%) and >1 level higher 25% of the time (25 of 101; 1-tailed 95% CI: >18%). The distribution of the clinical estimates found clinicians locating the intercristal line at L3 or L3-4 54% of the time (54 of 101; 95% CI: 44%, 63%) and at L2-3 or higher 27% of the time (27 of 101; 1-tailed 95% CI: >20%). CONCLUSION: The anatomical position of the intercristal line was at L3 or higher in at least 6% of term pregnant patients using ultrasound. Clinical estimates were found to be ≥1 vertebral level higher than the anatomical position determined by ultrasound at least 40% of the time. This disparity may contribute to misidentification of lumbar interspaces and increased risk of neurologic injury during neuraxial anesthesia.

Infection associated with central venous or epidural catheters: how to reduce it?

PURPOSE OF REVIEW Central venous catheters are a leading source of nosocomial bloodstream infection with an estimated 10% mortality. Infection associated with epidural catheterization is an uncommon but devastating complication. Diagnosis of spinal epidural abscess requires a high index of suspicion and imaging techniques such as MRI. Early diagnosis and treatment will minimize permanent damage, but primary prevention should be the aim, which depends on proper patient evaluation and use of full aseptic precautions. RECENT FINDINGS Recent studies suggest that epidural infection is no longer as rare a complication as once thought and may be increasing. It is not clear whether this increase is related to an increase in reporting, an overall increase in the total number of epidurals (especially extended use) being performed, or a true increase in infection rate. Implementation of multistep prevention programs has been shown to decrease central venous catheter-related bloodstream infection rate. Antiseptic or antibiotic-impregnated central venous catheters are effective in decreasing central venous catheter-related bloodstream infections. SUMMARY Healthcare worker education and training are essential to create standardization of aseptic care. Continuous surveillance is necessary for identifying lapses in infection-control practices.

Spontaneous rupture of uterus

Spontaneous rupture of the uterus is a life-threatening obstetrical emergency. Diagnosis may be delayed because of the bizarre presentation or absence of significant pain and tenderness, which could have been masked by the analgesic medications used during labor. We present a case of spontaneous rupture in a multigravid female who was undergoing oxytocin-augmented labor while receiving epidural analgesia. She had had no previous cesarean deliveries or uterine surgery. Half an hour after an initial complaint of left inguinal pain, which was thought to be related to a patchy epidural block, she presented with changes in vital signs and significant fetal decelerations. At emergent cesarean section, a uterine rupture was noted. The uterine rupture extended down to the left vaginal angle, was not reparable and a hysterectomy was performed. The fetus survived.

Progress in analgesia for labor: focus on neuraxial blocks

Neuraxial analgesia is widely accepted as the most effective and the least depressant method of providing pain relief in labor. Over the last several decades neuraxial labor analgesia techniques and medications have progressed to the point now where they provide high quality pain relief with minimal side effects to both the mother and the fetus while maximizing the maternal autonomy possible for the parturient receiving neuraxial analgesia. The introduction of the combined spinal epidural technique for labor has allowed for the rapid onset of analgesia with minimal motor blockade, therefore allowing the comfortable parturient to ambulate. Patient-controlled epidural analgesia techniques have evolved to allow for more flexible analgesia that is tailored to the individual needs of the parturient and effective throughout the different phases of labor. Computer integrated systems have been studied to provide seamless analgesia from induction of neuraxial block to delivery. New adjuvant drugs that improve the effectiveness of neuraxial labor analgesia while decreasing the side effects that may occur due to high dose of a single drug are likely to be added to future labor analgesia practice. Bupivacaine still remains a popular choice of local anesthetic for labor analgesia. New local anesthetics with less cardiotoxicity have been introduced, but their cost effectiveness in the current labor analgesia practice has been questioned.

Fetal assessment for anesthesiologists: are you evaluating the other patient?

Suboptimal communication between anesthesiologists and obstetricians can be associated with unintended poor maternal and neonatal outcomes, especially for emergency cesarean deliveries. Obstetricians use the results of antepartum and intrapartum fetal assessments to assess fetal well-being and to make decisions about the timing and method of delivery. Because abnormal results may lead to the need for urgent or emergency cesarean deliveries, these decisions may directly impact anesthetic care. Lack of familiarity with fetal assessments and the significance of the results may thus hinder the communication necessary for optimal patient care. In this review article, we discuss the current antepartum and intrapartum fetal assessment modalities, including the nonstress test, biophysical profile, Doppler velocimetry, electronic fetal heart rate monitoring, fetal electrocardiogram (STAN-ST waveform analysis), and fetal pulse oximetry. The physiologic basis behind these modalities and the available evidence regarding their utility in clinical practice are also reviewed. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring categories, which are incorporated into the American College of Obstetricians and Gynecologists guidelines for intrapartum care, is examined. The implications of test interpretation to the practice of obstetric anesthesiology is also discussed. Anesthesia provider understanding of fetal assessment modalities is essential in improving communication with obstetricians and improving the planning of cesarean deliveries for high-risk obstetric patients.

Anesthesia Complications in the Birthplace: Is the Neuraxial Block Always to Blame?

This article highlights the common and some of the very serious complications that may occur following neuraxial analgesia for labor and delivery, including headache, backache, infection, hypotension, and hematoma. Total spinal and failed block also are discussed, as are complications unique to epidural anesthesia, such as the intravascular injection of large volumes of local anesthetic (causing seizure or cardiac arrest) and accidental dural puncture.

Complete heart block in pregnancy: case report, analysis, and review of anesthetic management

Maternal complete heart block can pose significant challenges for the anesthesiologist in the antepartum, peripartum, and postpartum periods. Some patients may present for the first time in the puerperium with dizziness, weakness, syncope, or congestive heart failure as a result of the additional hemodynamic burden that accompanies pregnancy. Although there is an increase in permanent pacemaker placement in young symptomatic patients before pregnancy, prophylactic placement of pacemakers in asymptomatic parturients is not always indicated. The need for temporary or permanent pacemakers in asymptomatic women should be assessed on a case-by-case basis; many of these patients may be safely managed during labor and delivery without pacing. The parturient with complete heart block must be followed vigilantly during pregnancy and post delivery, as the need for pacemaker insertion can also arise in the postpartum period. We present a case of third-degree heart block in a 26-year-old parturient.

Anesthetic Considerations for the Parturient after Solid Organ Transplantation

Over the past 40 years, the success of organ transplantation has increased such that female solid organ transplant recipients are able to conceive and carry pregnancies successfully to term. Anesthesiologists are faced with the challenge of providing anesthesia care to these high-risk obstetric patients in the peripartum period. Anesthetic considerations include the effects of the physiologic changes of pregnancy on the transplanted organ, graft function in the peripartum period, and the maternal side effects and drug interactions of immunosuppressive agents. These women are at an increased risk of comorbidities and obstetric complications. Anesthetic management should consider the important task of protecting graft function. Optimal care of a woman with a transplanted solid organ involves management by a multidisciplinary team. In this focused review article, we review the anesthetic management of pregnant patients with solid organ transplants of the kidney, liver, heart, or lung.

Obstetric Anesthesiologists as Perioperative Physicians: Improving Peripartum Care and Patient Safety

The care of obstetric patients has become challenging due to the changing demographics of the pregnant population. Women with chronic diseases and congenital heart disease live to child-bearing age due to medical and surgical advances. Older and less healthy women become pregnant due to advances in reproductive technologies. Therefore, obstetric anesthesiologists have an increasingly important role in the peripartum period. In this article, we review the role of obstetric anesthesiologists in the antepartum, intrapartum, and postpartum periods. The need for multidisciplinary care of high-risk parturients is discussed, including the role of anesthesiologists in the National Maternal Health Initiative to improve maternal morbidity and mortality.