Mild hypercapnia after uncomplicated heart surgery is not associated with hemodynamic compromise

OBJECTIVE: The aim of this study was to examine the effects of small changes in PaCO(2) on hemodynamic parameters after uncomplicated heart surgery with cardiopulmonary bypass. DESIGN: This was a prospective, randomized crossover study. SETTING: A large academic medical center. PARTICIPANTS: Twenty-four subjects who were scheduled for elective cardiac surgery were enrolled in this study. INTERVENTIONS: Each subject underwent the normal procedures that are associated with cardiac surgery. General anesthesia, including muscle relaxation, were continued in the immediate postoperative period. Measured tidal volumes and minute ventilation were kept constant for the duration of the study. Target PaCO(2) concentrations of 30, 40, and 50 mmHg were achieved by adding varying amounts of exogenous CO(2) gas to the inhaled oxygen. Various measurements were made at each target PaCO(2), including cardiac index, mixed venous oxygen saturation, blood pressure, heart rate, and pulmonary artery pressure. MEASUREMENTS AND MAIN RESULTS: Twenty-four patients were enrolled. Seven were withdrawn before commencement of the study. The cardiac index increased when the PaCO(2) was increased from 30 to 40 mmHg (p < 0.001) and remained unchanged between 40 and 50 mmHg. Mixed venous oxygen saturation increased (p < 0.001) with elevations in PaCO(2) up to 50 mmHg and decreased again when the PaCO(2) was returned to 30 mmHg. The blood pressure decreased (p < 0.001) with increasing PaCO(2). The pulmonary pressure increased (p < 0.001) with elevations in PaCO(2). No patient became hemodynamically unstable or had any arrhythmias. CONCLUSION: The findings of this study suggest that unless there is a specific contraindication to mild hypercapnia, such as pulmonary hypertension or hemodynamic instability, concerns about mild respiratory acidosis should not prevent weaning of sedation and mechanical ventilation after uncomplicated heart surgery.     

Root Canal Shaping Using Nickel Titanium,M-Wire,and Gold Wire: A Micro–computed Tomographic Comparative Study of One Shape,ProTaper Next,and WaveOne Gold Instruments in Maxillary First Molars

Introduction

The aim of this study was to evaluate the root canal shaping effect of instruments manufactured from nickel titanium, M-Wire, and Gold wire with different glide path preparation techniques.

Comparison of tramadol and morphine via subcutaneous PCA following major orthopaedic surgery

Purpose

To compare subcutaneous PCA tramadol with subcutaneous PCA morphine for postoperative pain relief after major orthopaedic surgery and for the incidence of side-effects.

Methods

In a double-blind randomised controlled study 40 patients (20 in each group) self-administered either tramadol or morphine for 72 hr after surgery viasc PCA The following variables were recorded at various time intervals: (i) pain score by means of a visual analogue scale, (ii) drug consumption and total PCA demands, (iii) vital signs (blood pressure and heart rate), (iv) oxygen saturation and respiratory rate, and (v) side-effects (sedation, nausea/vomiting, pruritus, urinary retention and constipation).

Results

Both drugs provided effective analgesia. The mean consumption in the first 24 hr was 792 ± 90 mg tramadol and 42 ± 4 mg morphine. Thereafter, consumption of both drugs declined markedly. Moderate haemodynamic changes were observed in both the tramadol and morphine groups (with a maximum 20% decrease in mean blood pressure and a maximum 17% increase in heart rate) during the 72 hr period. Both tramadol and morphine were associated with a clinically and statistically significant (P < 0.001) decrease in oxygen saturation, but without changes in respiratory rates. Desaturation was less marked with tramadol. Tramadol appeared to cause more nausea and vomiting than morphine. Sedation was mild and only seen during the first few hours after surgery in both groups.

Conclusion

Tramadol is an effective analgesic agent for the relief of acute postoperative pain when administered by PCA via the subcutaneous route. Under these conditions tramadol behaves much like morphine with a similar side-effect profile.     

Attitude of a group of South Africans toward advertising by dentists in private practice]

The advertising of dental services in South Africa is controlled by rules and regulations of the South African Medical and Dental Council. According to these, advertising is not permissible with the exception of specified professional information which may be made known only by means of a nameplate and an entry in a telephone directory. Questionnaires were sent to a randomised sample of 2,100 persons in order to determine the attitude of South Africans towards advertising by private practitioners. According to information obtained from this study there is a strong indication that consumers of dental services prefer a freer form of advertising by dentists in the private practice.     

Why parents refuse newborn hearing screening and default on follow-up rescreening—A South African perspective

Objectives

This study describes screen refusal and follow-up default characteristics together with caregiver reasons for screen refusal and follow-up default in two South African universal newborn hearing screening programs.

Methods

A retrospective record review of universal newborn hearing screening conducted at two hospitals (Hospital A n = 954 infants; Hospital B n = 2135) over a 31–33 month period. Otoacoustic emission screening was conducted with rescreen recommended within six weeks for a uni- or bilateral refer. Program efficacy was described according to coverage, referral and follow-up rates. A prospective telephonic interview with caregivers who declined the initial screen (n = 25) and who defaulted on follow-up (n = 25) constituted the next study component. Caregivers were randomly selected from the screening programs for a survey related to reasons for newborn hearing screening refusal and follow-up default.

Results

Screening coverage (89.3% Hospital A; 57.4% Hospital B), initial referral rates (11.6% Hospital A; 21.2% Hospital B) and follow-up return rates (56.1% Hospital A; 35.8% Hospital B) differed significantly between hospitals and were below benchmarks. The most frequent reasons for screen refusal were related to costs (72%), caregiver knowledge of newborn hearing screening (64%) and health care professional knowledge and team collaboration (16%). Almost all caregivers (96%) indicated that if costs had been included in the birthing package or covered by medical insurance they would have agreed to newborn hearing screening. Reasons for follow-up default were most commonly related to caregiver knowledge of newborn hearing screening (32%) and costs (28%). One in four caregivers (24%) defaulted on follow-up because they forgot to bring their infant for a rescreen. Only half of caregivers (48%) who defaulted on follow-up reported being aware of initial screen results while 60% reported being aware of the recommended follow-up rescreen.

Conclusion

Caregivers most commonly refused screening due to associated costs and mostly defaulted on follow-up due to an apparent lack of knowledge regarding initial screen outcome and recommendations made for follow-up. Including NHS as a mandated birthing service is essential if coverage is to be increased, while reducing follow-up defaults requires proactive reminders and improved communication with caregivers.