Pulse oximetry-guided rational use of oxygen in patients for ambulatory surgical procedures under spinal anesthesia

Background: In an effort to prevent and address perioperative hypoxemia, it has become customary to provide supplemental oxygen to all surgical patients. Recently, the value of such a practice has been questioned. This study was designed to determine the incidence as well as the potential risk factors associated with perioperative hypoxemia. Methods: During a 9 - week period, 84 ASA I-II patients who underwent ambulatory surgical procedures under spinal anesthesia were observed. Arterial oxygen saturation (SpO2) was monitored using a pulse oximeter prior to induction of anesthesia, during operation and until the patient was discharged from the recovery room. Patients breathed room air during the entire perioperative course unless dyspnea and/or desaturation occurred. Descriptive statistics was used to examine differences in oxygen saturations before, during, and after surgery. The association between each of the potential risk factors and the number of patients requiring supplemental oxygen was analyzed using Fisher's exact test (for attribute data e.g. level of sensory block) and the Wilcoxon's rank sum test for continuous data (e.g. age, smoking in pack years) to calculate the probability that the proportions did not differ. A/>< 0.05 was considered statistically significant. Results: The incidence of preoperative, intra-operative and postoperative hypoxemia was 0 percent, 0 percent and 1.14 percent respectively while the need for supplemental oxygen was 2.27 percent intra-operatively and 2.27 percent postoperatively. Statistical analysis revealed that the level of block and body mass index were significant factors (P < 0.05) influencing the need for oxygen support. The need for supplemental oxygen was not associated with age, smoking history, surgical position, sedation level and Visual Analog Scale score. Conclusion: Results suggest that seemingly healthy patients who undergo lower abdominal, urologic, gynecologic or lower extremity surgical procedures under spinal anesthesia are at a low risk for hypoxemia. Pulse oximetry as part of routine monitoring may obviate the need for supplemental oxygen in this patient population. (Author)

The effect of the walking epidural technique on maternal pain relief and the progress of labor in nulliparous patients: A randomized controlled trial comparing the effects of standard epidural analgesia and the combined spinal epidural analgesia techniques for labor

Background: While the standard lumbar epidural analgesia technique has often been described as the gold standard for pain relief during labor, its disadvantages of delayed onset and the presence of motor blockade to a certain degree pose several constraints to pain burdened mother who also may not want to be confined in the supine position during the entire labor process. An alternative which may address these issues is the combined spinal epidural or walking epidural technique. We embarked on this study to compare both techniques in terms of onset and degree of analgesia and the outcome of labor. Methods: Eighty (80) nulligravid ASA 1-2 term patients were randomly assigned to receive labor pain relief either using the standard continuous lumbar epidural analgesia (CLEA) using .125 percent bupivacaine with fentanyl or the combined spinal epidural analgesia (CSE) technique using intrathecal fentanyl and bupivacaine followed by bupivacaine boluses with fentanyl as needed. Outcome measures studied were Visual Analogue Pain Scores, onset degree and duration of pain relief and the progress and outcome of labor including neonatal outcome. Side effects were also noted. Results: Very significant was the rapid onset of action, denser, and longer duration of pain relief in the CSE group. Likewise a faster rate of cervical dilation resulting in a shorter first stage of labor was noted. Second stage duration and mode of delivery in both groups however did not differ significantly. Maternal satisfaction during the first stage was greater in the CSE group, although overall maternal satisfaction was comparable in both groups. Pruritus, although a significant occurrence in the CSE group did not need any intervention for treatment. No adverse effects on both the neonate and mother were noted. Conclusion: Based on the results of our study, the CSE or walking epidural is a encouraging alternative to laboring mothers, especially those in severe pain requiring rapid and profound relief. Our results show that compared the standard epidural technique, it hastens the rate of first stage labor - but whether ambulation plays a significant role in this aspect needs to be further investigations

Evidence-based clinical practice guidelines on seeking referral for preoperative cardiac evaluation for elective noncardiac surgery

The Philippine Council for Health Research and Development-Department of Science and Technology (PCHRD-DOST), and the Philippine College of Surgeons (PCS) signed a Memorandum of Agreement on 1 June 1999, whereby both agreed to support the formation of Evidence-Based Clinical Practice Guidelines (EBCPGs) on specific areas of surgical care in the Philippines. The areas were to be specified by the PCS, and those areas should have a reasonably large potential of improving the quality of patient care throughout the country, and can be implemented nationwide in both government and private health facilities The first clinical area selected was on when to refer for preoperative cardiac evaluation for elective noncardiac surgery, and when would the intraoperative presence of a cardiologist be beneficial. A Technical Working Group (TWG) was appointed, which: 1) searched and appraised the evidence; 2) prepared a first draft EBCPG; 3) presented the evidence to a Panel of Experts; 4) supervised the panel using the nominal group technique (6 November 1999 - PCS Building); and 5) prepared the second draft EBCPG based on the consensus recommendations of the panel. All processes strictly conformed to the methods of evidence-based guidelines formation specified by evidence-baesd medicine texts The second draft EBCPG was presented on 11 December 1999 during the 55th Clinical Congress of the PCS, and the final draft approved by the PCS Board of Regents on 29 January 2000 Literature search was conducted through the MEDLINE, COCHRANE Library an the HERDIN Database. A total of 2,156 titles, 427 abstracts and 77 full text articles were appraised. Data from 23 prospective cohort studies were encoded into the software COCHRANE Review Manager (RevMan), Version 3.0 for Windows (updated October 7, 1996). Tables were generated which contained authors, outcome rates, relative risks and the 95% confidence intervals of the relative risks. Three perioperative outcomes were identified-cardiac morbidity, cardiac death, and overall cardiac events

The effect of the spinal needle tip design on the incidence of postdural puncture headache: A randomized double-blind study on 200 obstetic patients

BACKGROUND: A myriad of foreign studies have shown the advantage of a pencil-point spinal needle (Whitacre) in reducing the incidence of post-ducal puncture headache (PDPH), especially in the population most at risk for PDPH - the obstetric patients. In the Philippines, there has been no data comparing the incidence of PDPH between the standard spinal needle (Quincke) and the newer Whitacre needle. This study aims to compare the incidence of spinal headache between the Quincke and the Whitacre spinal needle in Filipino obstetric patients. METHODS: A randomized double-blind study was conducted on 200 obstetric patients for elective cesarean sections under subarachnoid anesthesia using either a Quincke or a Whitacre spinal needle of the same gauge (G25). The incidence and quality of post-ducal puncture headache was compared between the two groups. Both groups were also compared in terms of ease of lumbar puncture, quality of motor block, and the incidence of postoperative complications RESULTS: The incidence of PDPH was significantly higher in the Quincke group (8 percent) as compared to the Whitacre group (1 percent). The case of insertion of the spinal needle was considered effortless (1 attempt) in 67 percent of the Quincke group and in 61 percent of the Whitacre group. Degree of motor blockade was noted to be more solid in the Whitacre group (93 percent) as compared to 83 percent in the Quincke group. There were 2 failed spinal attempts in the Quincke group and 3 in the Whitacre group for which general anesthesia was resorted to. Other postoperative complications of non-spinal headache (Quincke- 4 percent vs. Whitacre- 3 percent) and backache or back soreness as specified by the patients (Quincke 12 percent vs Whitacre 15 percent) did not differ significantly. CONCLUSION: Results imply that the G25 Whitacre needle with a conical, non-cutting bevel is an improved alternative to the G25 Quincke needle in terms of reducing the incidence and quality of postdural puncture headache in Filipino obstetric patients. The design of the spinal needle tip influences the occurrence of PDPH. (Author)

Crystalloid preloading in elective cesarean section under spinal anesthesia

BACKGROUND: The prevention of maternal hypotension by traditional crystalloid preloading prior to spinal anesthesia in obstetric patients undergoing spinal anesthesia has recently been questioned by many. A review of published data with unbiased comparison comparing preloading and no preloading prior to spinal anesthesia was attempted to assess the relative benefits and side-effects in terms of incidence of maternal hypotension, dose of vasopressors given and APGAR scores at one and 5 minutes. METHODS: A medline search of published randomized controlled trials (RCT) from 1966-1997 comparing crystalloid and no crystalloid preloading prior to spinal anesthesia in patients for cesarean section was done. Search for available meta-analysis on preloading, only three met the criteria for analysis. The outcome measures were limited to three due to lack of available data for comparison. RESULTS: Using the Peto Odds Ratio, analysis of the three studies showed no significant difference in the incidence of hypotension between those who were preloaded and those who were not. But a trend towards a lower incidence of hypotension among those who were preloaded was seen. Using the weighted means difference (WMD) to analyze the dose of vasopressors given, there was no significant difference between preloading and no preloading but a trend towards a greater total dose of vasopressors was seen in those not preloaded. There was no significant difference in APGAR scores in the three studies. CONCLUSION: There is no sufficient evidence to support a change in practice to no preloading prior to spinal anesthesia for elective cesarean section based on the results of this meta-analysis. Further studies must be done to increase the validity and precision of results comparing preloading and no preloading.