Continuous Oxygen Saturation Monitoring Research Articles

Half a Decade of Intravenous Ketamine Administration: Our Observation Results and Insights regarding its safety

IntroductionKetamine, originally an anesthetic, has emerged as a potent tool in the fight against treatment-resistant depression and suicide. Clinical trials have demonstrated its ability to induce remission of severe depressive symptoms, with effects that can extend over several weeks.Furthermore, research highlights Ketamine’s potential to rapidly reduce suicidal ideation. This suggests Ketamine’s role as an intervention in suicide prevention, especially when conventional treatments prove ineffective. While isolated cases report severe respiratory depression, primarily when combined with other medications, most incidents involve temporary apneic episodes following high-dose intravenous administration. Understanding Ketamine’s safety profile is vital for its clinical optimization and ensuring patient well-being during useObjectivesThis presentation serves to describe, and evaluate our clinic’s safety protocol implemented for intravenous (IV) Ketamine infusions at the General Hospital of Corfu. Our primary goal is to rigorously assess the safety and tolerability of IV Ketamine in a clinical settingMethodsPatients must meet stringent criteria:-Exclude those over 70.-MMSE score above 25.-Controlled blood pressure.-No cardiac insufficiency, myocardial ischemia, or high intraocular/intracranial pressure.-Absence of thyrotoxicosis, psychosis, or seizures.Pre-infusion comprehensive evaluation:-Includes ECG, blood biochemistry studies, and frequent blood pressure checks.-Requires a 2-hour fast.Ketamine infusion:-IV Ketamine administered at 0.5mg/kg in 100ml N/S.-Continuous monitoring of oxygen saturation (PO2) and cardiac rhythm.-Blood pressure checks every 15 minutes.Treatment typically involves 7 sessions over a span of a month, with an initial test dose of 0.25 mg/kg.ResultsKetamine infusions were administered to a total of 208 patients. The majority of participants experienced a slight increase in blood pressure, while there were no significant changes in cardiac rhythm. Additionally, almost all patients reported experiencing dizziness or headaches during the infusion. Notably, nearly half of the patients reported an alteration in taste perception as a side effect. It’s important to highlight that all observed side effects, spontaneously resolved within an hour after the conclusion of the infusion. However, in a small subset of cases (six instances), the side effects were severe enough to necessitate the premature termination of the ketamine infusionConclusions Although ketamine demonstrates a favorable safety profile with minimal major side effects when administered following our established safety protocol. However, we want to underscore the critical importance of vigilant patient monitoring during ketamine administration and the prompt addressing of any adverse effects. This proactive approach is paramount to ensure the safety and overall well-being of patients receiving ketamine treatmentDisclosure of InterestNone Declared

Possibility of using therapeutic massage in rehabilitation after covid-19

Purpose of the research was to assess the influence of an individual classical back massage session as well as the effects of an entire 8-session back massage therapy on cardiological and spirometry parameters in a patient after recovering from COVID-19, with constant monitoring of massage areas’ temperature changes. Continuous oxygen saturation monitoring during the massage sessions enabled to observe a decrease in the level of this parameter during utilisation of rubbing and tapotement on muscles of both the right and the left side of the back. During the usage of the intense massage techniques SaO2 dropped maximally to 92– 93%. The observed changes in the VA/Q ratio that occurred in response to the 8-session massage therapy lasting for 3 weeks might indicate that better conditions for ventilation and oxygen perfusion at the alveolar surface were reached. This translated in the patient who recovered from COVID-19 into 2% increase in oxygen saturation level after completing the massage therapy. Conclusion. Utilising the intense rubbing and tapotement techniques has to be carefully considered due to their significant influence on decrease in the level of saturation.

Association between Nocturnal Hypoxemia and COPD Severity: A Cross-sectional Study

Introduction: Globally, Chronic Obstructive Pulmonary Disease (COPD) is the third most common cause of mortality. More than 80% of these fatalities happened in low- and middleincome nations. Transient desaturation during sleep occurs in healthy persons during Rapid Eye Movement (REM) sleep. This phenomenon is aggravated in COPD patients. As Nocturnal Desaturation (NOD) in COPD has been suggested to increase mortality, its early identification will aid in early initiation of treatment and prevention of associated complications. Aim: To estimate the prevalence of nocturnal hypoxemia in COPD and determine its association with COPD severity. Materials and Methods: A cross-sectional study was carried out at the Department of General Medicine, Apollo Hospitals, Guwahati, Assam, India during January to December 2021 involving 100 patients who had COPD symptoms. Continuous oxygen saturation monitoring with transcutaneous finger probe was done for the entire duration of sleep at night. Patients whose oxygen saturation falls below 90% for at least 30% of recording time in sleep were classified as desaturators. Statistical Package for Social Sciences (SPSS) Version 26.0 was used for data analysis. Using the Chi-square test, the relationship between the qualitative variables was evaluated. The Mann-Whitney test or the unpaired t-test was used to analyse the quantitative data between the two groups. A p-value of less than 0.05 was considered significant. Results: Prevalence of NOD among cases of COPD was observed as 26% in present study. A significant association was observed between presence of NOD in COPD cases with severity of COPD and with desaturation in 6-Minute Walk Test (6-MWT) (p<0.01). Severe cases had a prevalence of NOD as 65% as compared to 28.2% and 4.9% in moderate and mild cases respectively (p<0.01). A total of 61.9% cases with desaturation during 6-MWT showed NOD as compared to 38.1% without desaturation (p<0.01). Conclusion: One fourth of the normoxemic COPD patients had significant NOD. NOD episodes were observed to be positively associated with increasing severity of COPD. Assessing variations in oxygen saturation during a 6-MWT can be helpful in identifying COPD patients who may be at risk for severe night time desaturation.

Wireless implantable optical probe for continuous monitoring of oxygen saturation in flaps and organ grafts

Continuous, real-time monitoring of perfusion after microsurgical free tissue transfer or solid organ allotransplantation procedures can facilitate early diagnosis of and intervention for anastomotic thrombosis. Current technologies including Doppler systems, cutaneous O2-sensing probes, and fluorine magnetic resonance imaging methods are limited by their intermittent measurements, requirements for skilled personnel, indirect interfaces, and/or their tethered connections. This paper reports a wireless, miniaturized, minimally invasive near-infrared spectroscopic system designed for uninterrupted monitoring of local-tissue oxygenation. A bioresorbable barbed structure anchors the probe stably at implantation sites for a time period matched to the clinical need, with the ability for facile removal afterward. The probe connects to a skin-interfaced electronic module for wireless access to essential physiological parameters, including local tissue oxygenation, pulse oxygenation, and heart rate. In vitro tests and in vivo studies in porcine flap and kidney models demonstrate the ability of the system to continuously measure oxygenation with high accuracy and sensitivity.

Invasive And Non-invasive Assessment Of Arterial Blood Oxygen Saturation In Patients With Continuous Flow LVADs: Is There A Correlation?

<h3>Background</h3> Patients with continuous flow left ventricular assist devices (CF-LVAD) typically have a narrow pulse pressure. This may pose a challenge for transcutaneous automated pulse oximeter devices to accurately measure arterial blood saturation. This study aimed to assess their accuracy in a CF-LVAD population by comparing pulse oximetry readings to invasive arterial blood gas (ABG) measurements. <h3>Methods</h3> A total of eighteen patients with a CF-LVAD were identified using chart review at the University of Minnesota and Minneapolis Heart Institute. All, except one patient were implanted with a HeartMate III device (Abbott Laboratories, Minneapolis, MN). Non-invasively assessed oxygen saturation was compared to simultaneously obtained arterial blood oxygen saturation. Two patients were receiving mechanical ventilation, one received BiPAP support, and 15 patients were either breathing room air or receiving supplemental oxygen by nasal cannula. <h3>Results</h3> A non-invasive pulse oximeter read was obtained on every patient. There was a moderate correlation between the invasively and non-invasively obtained oxygen saturation values as shown in Figure 1 (R²=0.624). Waveform quality, as assessed by the treating physician, qualified as good or acceptable in 16 cases and as poor for 2 patients. Data points for these 2 patients are marked in red in Figure 1. <h3>Conclusion</h3> Despite a narrow pulse pressure in patients with CF-LVAD, non-invasive pulse oximetry provided a reliable assessment of arterial blood saturation when compared to the gold standard ABG measurement. This finding presents an opportunity to conduct future studies in this patient population in which continuous monitoring of oxygen saturation may be necessary, such as evaluation for obstructive sleep apnea.

Evaluation of fingertip pulse oximeters for monitoring haemoglobin oxygen saturation in arterial blood and pulse rate in isoflurane‐anaesthetised horses breathing greater than 90 percent oxygen

SummaryBackgroundPulse oximetry is a noninvasive method for continuous monitoring of oxygen saturation (SpO2) and pulse rate (PR) used in equine anaesthesia. Despite species differences in the oxyhaemoglobin dissociation curve, pulse oximeters validated for humans are commonly used in veterinary medicine. These devices are expensive and at an increased risk for damage when used for equine anaesthesia. Human fingertip pulse oximeters (FPO) may be useful as an inexpensive alternative to standard devices.ObjectivesEvaluate accuracy and repeatability of FPOs applied to tongues of anaesthetised horses breathing &gt;90% oxygen.Study designProspective clinical study.MethodsDuplicate SpO2 and PR measurements from eight pulse oximeters (PO; seven FPOs and reference PO) placed in random order on tongues of horses under inhalational anaesthesia were recorded. A standard portable PO (RPO) was used as reference SpO2 and invasive blood pressure trace or manual pulse palpation as reference PR. Nonparametric Bland‐Altman analysis was performed. Acceptable coefficient of repeatability (CR) value was ≤6% SpO2. Agreements were accepted if limits of agreement were ≤ ±3% difference in SpO2 and ≤ ±10% relative difference in PR. Only PR values between 25 and 50 beats per minute and their corresponding SpO2 measurements were used for agreement analysis.ResultsSpO2 repeatability and agreement were unacceptable for all devices. The agreement of PR measurements was acceptable for one FPO and the RPO.Main limitationsUtilisation of devices designed for the human oxyhaemoglobin dissociation curve, high number of absent or erroneous readings, use of healthy horses, small sample size, unavailability of co‐oximetry, lack of a desaturation protocol and difficulty with proper placement of FPOs on horse tongues are all considered limitations in this study.ConclusionsAccuracy of FPOs used in anaesthetised horses was poor. Their use in equine anaesthesia for SpO2 monitoring is not recommended, but some models may be considered for continuous PR monitoring in conjunction with intermittent manual confirmation.

Intramuscular Near-Infrared Spectroscopy for Muscle Flap Monitoring in a Porcine Model.

Current near-infrared spectroscopy (NIRS)-based systems for continuous flap monitoring are limited to flaps which carry a cutaneous paddle. As such, this useful and reliable technology has not previously been applicable to muscle-only free flaps where other modalities with substantial limitations continue to be utilized. We present the first NIRS probe which allows continuous monitoring of local tissue oxygen saturation (StO2) directly within the substance of muscle tissue. This probe is flexible, subcentimeter in scale, waterproof, biocompatible, and is fitted with resorbable barbs which facilitate temporary autostabilization followed by easy atraumatic removal. This novel device was compared with a ViOptix T.Ox monitor in a porcine rectus abdominus myocutaneous flap model of arterial and venous occlusions. During these experiments, the T.Ox device was affixed to the skin paddle, while the novel probe was within the muscle component of the same flap. The intramuscular NIRS device and skin-mounted ViOptix T.Ox devices produced very similar StO2 tracings throughout the vascular clamping events, with obvious and parallel changes occurring upon vascular clamping and release. The normalized cross-correlation at zero lag describing correspondence between the novel intramuscular NIRS and T.Ox devices was >0.99. This novel intramuscular NIRS probe offers continuous monitoring of oxygen saturation within muscle flaps. This experiment demonstrates the potential suitability of this intramuscular NIRS probe for the task of muscle-only free flap monitoring, where NIRS has not previously been applicable. Testing in the clinical environment is necessary to assess durability and reliability.

Limited resources restrict the provision of adequate neonatal respiratory care in the countries of Africa.

Over two thirds of newborn deaths occur in Africa and South Asia, and respiratory failure is a major contributor of these deaths. The exact availability of continuous positive airway pressure (CPAP) and surfactant in Africa is unknown. The aim of this study was to describe the availability of newborn respiratory care treatments in the countries of Africa. Surveys, in English, French and Portuguese, were sent to neonatal leaders in all 48 continental countries and the two islands with populations over 1million. Forty-nine (98%) countries responded. Twenty-one countries reported less than 50 paediatricians, and 12 countries had no neonatologists. Speciality neonatal nursing was recognised in 57% of countries. Most units were able to provide supplemental oxygen. CPAP was available in 63% and 67% of the most well-equipped government and private hospitals. Surfactant was available in 33% and 39% of the most well-equipped public and private hospitals, respectively. Availability of CPAP and surfactant was greatly reduced in smaller cities. Continuous oxygen saturation monitoring was only available in 33% of countries. The availability of proven life-saving interventions in Africa is inadequate. There is a need to sustainably improve availability and use of these interventions.

Polysomnography parameters as predictors of respiratory adverse events following adenotonsillectomy in children

The first-line treatment of obstructive sleep apnea syndrome in children is adenotonsillectomy, but this may result in perioperative respiratory adverse events (PRAEs). The primary aim of this study is to examine whether the McGill oximetry score (MOS) and other polysomnography parameters can predict major PRAEs following adenotonsillectomy. We secondarily evaluated the MOS interrater reliability and correlation with other polysomnography parameters. This retrospective study included all children aged 0-18 years who underwent preoperative polysomnography between June 2010 and January 2016 prior to adenotonsillectomy at a tertiary pediatric institution. Oximetries from polysomnograms were assigned an MOS. Univariable and multivariable models for prediction of major PRAEs were constructed. MOS was correlated with polysomnography parameters and interrater reliability was evaluated. This study included 106 children; 15 had a major PRAE. A multivariable prediction model that combined MOS and age showed evidence for the ability to predict major PRAEs with an area under the receiver operating characteristic curve of 0.68 (95% confidence interval: 0.52, 0.84), whereby increased MOS and younger age were associated with PRAEs, but apnea-hypopnea index was not. MOS had excellent interrater reliability (κ = 0.95) and was highly correlated with oxygen saturation nadir and cumulative time percentage with oxygen saturation less than 90%. A prediction model including MOS and age may predict PRAEs following adenotonsillectomy. This suggests that nocturnal oximetry provides the most essential information of polysomnography measures to direct postoperative monitoring following adenotonsillectomy. Xiao L, Barrowman N, Momoli F, etal. Polysomnography parameters as predictors of respiratory adverse events following adenotonsillectomy in children. J Clin Sleep Med. 2021;17(11):2215-2223.

Strategies to Prevent Severe Retinopathy of Prematurity: A 2020 Update and Meta-analysis.

The incidence of retinopathy of prematurity (ROP) is showing an increasing trend in the United States. This may be because of increasing survival rates among extremely preterm infants (<25 weeks' gestation) and targeting higher oxygen saturation. Five randomized clinical trials of low versus high oxygen saturation target ranges found increased mortality in the low oxygen saturation target group and an increased incidence of ROP in the high oxygen saturation target group. The American Academy of Pediatrics recommends using an oxygen saturation target range of 90% to 95% in extremely low-birthweight infants. The change of practice to target this higher oxygen saturation range, from admission until discharge, may be contributing to the increasing incidence of ROP in extremely preterm infants. To decrease the incidence of ROP without increasing mortality, 2 new cohort trials suggest gradually increasing oxygen saturation targets as preterm infants mature. There is evidence that human milk, vitamin A, and omega-3 fatty acids can help, in addition to continuous oxygen saturation monitoring, to decrease the risk of ROP. We review this literature and provide a meta-analysis to evaluate the evidence.

Recognition and Prevention of Visual Loss Due to Retinopathy of Prematurity in High Risk Twin Infant Pairs: A Case Series with a Multi-specialty Approach

Aim: This study was performed to determine profile of asymmetry, newer differences in postnatal risk factors and effects of current laser treatment on retinopathy of prematurity (ROP) progression in preterm twin pairs.&#x0D; Methods: A retrospective study was conducted on 250 infants (125 twin pairs) of premature birth, low weight or other infant risk factors at Sri Ramachandra hospital, a tertiary referral hospital in Chennai, India from May 2017 to April 2019. Indirect ophthalmoscopy with scleral indentation was performed on all babies under continuous monitoring of oxygen saturation using pulseoximeter in the presence of a neonatologist. Examination and analysis was done for stage and zone of ROP, systemic causes, spontaneous regression and need for treatment.&#x0D; Results: Among 125 twin pairs, 38twin pairs (30%) had ROP which was asymmetrical in 27% and symmetrical in 4%. Disparity developed before 35 weeks when both twins had ROP. Two stage differences occurred in 84%. Both were statistically significant (p&lt;0.05). Spontaneous regression occurred after 35 weeks and majority regressed by 40 weeks. Laser treatment was required in 36%. Risk factors were most commonly respiratory distress, patent ductus arteriosus, apnoea, variation of birth weight and gestational age.&#x0D; Conclusion: Smaller gestational age is a good predictor of variability in progression of vascularization and along with birth weight and weight gain contributes to asymmetry. Respiratory distress has the highest risk. It is important to screen and follow up all twins irrespective of initial examination status and normal appearing retina in one twin, as transition from one stage to another can occur. Early detection with timely treatment will prevent irreversible visual loss.

Practice variation in the management of children hospitalized with bronchiolitis: A Canadian perspective.

To describe variations in the monitoring, treatment, and discharge of children hospitalized with bronchiolitis among physicians across Canadian paediatric teaching hospitals. We conducted an electronic survey of paediatricians with experience in the management of inpatient bronchiolitis at 20 Canadian paediatric teaching hospitals. Only physicians who worked a minimum of 6 weeks on their hospital inpatient unit in the 2015 calendar year were eligible to participate in the study. The questionnaire explored the monitoring, treatment, and discharge of children with bronchiolitis. Central tendency (mean) and dispersion (SD) statistics were produced for continuous variables and frequency distributions for categorical variables. A total of 142 respondents were included in the analysis. 45.1% reported the routine use of continuous oxygen saturation monitoring. 27.5% used a higher cut-off for oxygen supplementation of 92% and 12.7% use a lower cut-off of 88%. 29.6% routinely used deep nasal suctioning. Seventy-three per cent reported using nebulized therapies. 55.6% reported having preprinted order sheets or guidelines for management of inpatient bronchiolitis at their institutions and 28.2% reported having specific discharge criteria. The length of time required to be off oxygen prior to discharge varied (31% at 12 hours, 27.5% at 24 hours, and 24.6% after the last sleep period without oxygen). There is significant practice variation in the monitoring, treatment, and discharge of children hospitalized with bronchiolitis within and between Canadian paediatric teaching hospitals. Future research is needed to establish best practices, effective knowledge translation, and implementation strategies to standardize care and decrease length of stay.

Intermittent versus continuous oxygen saturation monitoring for infants hospitalised with bronchiolitis: study protocol for a pragmatic randomised controlled trial

IntroductionBronchiolitis is the most common reason for hospitalisation in infants in developed countries. The main focus of hospital care is on supportive care, such as monitoring for hypoxia and supplemental...

Comparison of nasal and forehead oximetry accuracy and pressure injury in critically ill patients

BackgroundIn critically ill patients, clinicians can have difficulty obtaining accurate oximetry measurements. ObjectiveTo compare the accuracy of nasal alar and forehead sensor measurements and incidence of pressure injury. Methods43 patients had forehead and nasal alar sensors applied. Arterial samples were obtained at 0, 24, and 120 hours. Oxygen saturations measured by co-oximetry were compared to sensor values. Skin was assessed every 8 hours. ResultsOxygen saturations ranged from 69.8%-97.8%, with 18% of measures < 90%. Measurements were within 3% of co-oximetry values for 54% of nasal alar compared to 35% of forehead measurements. Measurement failures occurred in 6% for nasal alar and 22% for forehead. Three patients developed a pressure injury with the nasal alar sensor and 13 patients developed a pressure injury with the forehead sensor (χ2 = 7.68; p = .006). ConclusionsIn this group of patients with decreased perfusion, nasal alar sensors provided a potential alternative for continuous monitoring of oxygen saturation.

Procedural Sedation for Orthopedic Fracture Reductions in the Pediatric Emergency Department

Procedural Sedation for Orthopedic Fracture Reductions in the Pediatric Emergency Department

A reply

We thank Drs Patil and Maloney for their comment that supplementary oxygen may be beneficial for up to ten minutes after nitrous oxide anaesthesia and we would hope that continuous monitoring of oxygen saturation postoperatively will ensure that the oxygen dose is titrated to the patient's needs in these particular circumstances. Dr Gwinnutt suggests that our article 1 over-emphasised the risks of hyperoxaemia and type-2 respiratory failure but under-estimated the risks of hypoxaemia amongst patients cared for by anaesthetic colleagues. We agree that the best known example of oxygen sensitivity is the patient with acute exacerbation of chronic obstructive pulmonary disease (COPD), a condition much less common in anaesthetic and surgical practice than on medical wards. However, anaesthetists need to be aware that approximately 9% of UK adults aged > 65 have evidence of severe or very severe COPD on routine spirometry and about 2% of UK adults have morbid obesity, another condition where supplementary oxygen may cause hypercapnic respiratory failure 2-4. Patients with severe skeletal deformity or neuromuscular conditions causing hypercapnic respiratory failure may also present for surgery. In addition to these at-risk groups, even healthy adults can develop hypercapnic respiratory failure due to hypoventilation if given opioids. Audits at our institution found that 13% of blood gas specimens from surgical wards were hypercapnic (PCO2 > 6.0 kPa) compared with 29% of specimens from patients on medical wards, confirming that type-2 respiratory failure is less common (but not rare) on surgical wards. Type-2 respiratory failure was twice as common as type-1 (PO2 < 8.0 kPa with normal or low PCO2) on a hospital-wide basis 5, 6. We have analysed this audit database further and the results are shown in Table 1: type-2 respiratory failure is actually more common than pure hypoxaemia (type-1 respiratory failure) in blood gas samples from surgical wards, surgical HDU, theatres and ICU. Type-2 respiratory failure complicated by respiratory acidosis was commoner than type-1 failure on surgical HDU and in theatre and ICU and many additional patients had a mixed metabolic and respiratory acidosis. Our data also demonstrated that many patients in surgical and anaesthetic areas were hyperoxaemic including a high proportion with type-2 respiratory failiure. A random sample of casenotes identified risk factors for type-2 respiratory failure in 18% of the patients who required blood gas analysis on surgical wards and 23% from theatre samples. Education of medical students and junior doctors will need to reflect that type-2 respiratory failure is commoner than type-1, and that many patients with type-2 respiratory failure are hyperoxaemic due to oxygen therapy. Gwinnutt has not presented any evidence of benefit from the routine use of supplementary oxygen in postoperative care as distinct from our proposal to monitor patients carefully and give this drug to those who need it. The lack of likely benefit of routine supplemental postoperative oxygen, together with the potential hazards, were reviewed in detail by Downs and Rothen, who are both trained in anaesthesia 7, 8. We agree strongly with Gwinnutt that pulse oximetry and the administration of supplemental oxygen is only a small part of the assessment and resuscitation of at-risk patients, as discussed in the second paragraph of our editorial. We would guide readers to section 7 of the British Thoracic Society Emergency Oxygen Guideline which is devoted to the detailed clinical and laboratory assessment of seriously ill patients, and to Box 4 in our recent review of emergency oxygen use where we discuss several ways to increase tissue oxygen delivery, including the importance of airway management and blood transfusion when appropriate 9, 10.

Remifentanil PCA for labour analgesia

We read with great interest the recent letters documenting incidents of respiratory arrest in women in labour using remifentanil patient-controlled analgesia PCA 1-4. However, as a unit that routinely uses remifentanil PCA to provide popular and effective labour analgesia, we feel it is important to address some of the issues raised in these letters. Unlicensed drug use is common in obstetric anaesthetic practice, and patients must be made aware of the unlicensed use. A patient information leaflet about remifentanil PCA, given to women antenatally, is explicit on this point, which is confirmed verbally with each woman before the PCA is started. In addition, we continuously audit outcomes and adverse events (maternal and neonatal) for women receiving remifentanil PCA, and have been reassured of its safety over the last eight years. We administer remifentanil PCA to approximately 100 women in labour per month using a protocol that includes continuous oxygen saturation monitoring, the constant presence of a midwife, regular documentation of pain scores, respiratory rate and sedation level, and use of a dedicated cannula with an anti-syphon valve. As with all areas where strong parenteral opioids are administered, full resuscitation equipment is immediately available, with supplemental oxygen and ‘bag-valve-mask’ apparatus in the room. In the past two years we have had two significant incidents, both cases of marked respiratory depression, that resolved uneventfully after stopping the PCA and providing basic airway support (stimulation and facemask oxygen). We have not encountered patient dehydration in our practice related to remifentanil PCA 1. Our continuous audit process has also demonstrated high levels of satisfaction with remifentanil PCA, with many women returning to the unit and choosing the same method of analgesia for subsequent labours. Remifentanil PCA is now the analgesic choice in almost 30% of our deliveries, and since its introduction, the epidural rate in our unit has dropped by one third. There are risks with all methods of analgesia but we consider our experience, attained over several years, demonstrates that with strict protocols in place and one-to-one midwifery care, remifentanil PCA is safe, effective and popular for labour analgesia.

Early, reliable, utilitarian predictive factors for fat embolism syndrome in polytrauma patients

Background:Fat embolism is one of the apocalyptic pulmonary complications following high energy trauma situations. Since delay in diagnosis may have devastating consequences, early, easily accessible and relatively inexpensive investigations for risk stratification may prove useful, especially in developing nations.Materials and Methods:This prospective trial included a total of 67 young polytrauma patients, in whom the role of nine easily available, rapidly performable clinical or laboratory investigations (or observations noted at admission) in predicting the later occurrence of fat embolism syndrome were assessed. All the patients also underwent continuous monitoring of oxygen saturation with pulsoximetry.Results:The correlation between initial serum lactate (within 12 hours of injury) and hypoxia was statistically significant. There was a trend towards correlation with FES(by Gurd's criteria) (P=0.07), Sensitivity of 24-hour monitoring of oxygen saturation in predicting later pulmonary deterioration approached 100%.Conclusions:The combination of three factors including polytrauma (with NISS >17), serum lactate >22 mmol/l at admission (within 12 hours of injury) fall in oxygen saturation (SaO2 below 90% in the initial 24 hours) predict the development of post-traumatic pulmonary complications, especially the fat embolism syndrome.

Six‐minute walk test: observed adverse events and oxygen desaturation in a large cohort of patients with chronic lung disease

The 6-min walk test (6MWT) is widely used to assess patients with chronic lung disease (CLD). Anecdotal reports and studies in small numbers of patients with CLD suggest that complications associated with the 6MWT are rare. This study reports the incidence of observed adverse events during the 6MWT in patients referred to an outpatient pulmonary rehabilitation service. Seven hundred and forty-one patients with stable CLD (chronic obstructive pulmonary disease (COPD), n= 572) completed the 6MWT in accordance with a standardized protocol that included continuous monitoring of oxygen saturation (SpO(2)) and heart rate (Polar). Adverse events occurred in 43 tests (6%). One 6MWT was terminated by the tester because of chest pain and one patient developed persistent tachycardia and irregular pulse immediately following the test. In 35 tests, the tester instructed the patient to stop walking because of profound oxygen desaturation (SpO(2) < 80%). Six patients prematurely terminated the 6MWT because of symptoms. Forty-seven per cent (n= 345) of patients exhibited significant oxygen desaturation (≥4% fall in SpO(2) to <90%). Pre-exercise SpO(2) was a significant predictor of desaturation in the COPD (1.79, 1.54-2.08, adjusted odds ratio (OR), 95% confidence intervals) and ILD (OR 1.40, 1.11-1.77) cohorts with FEV(1) (forced expiratory volume in 1 s) also a predictor in COPD (OR 3.02, 1.77-5.15). Profound oxygen desaturation is the most common adverse event observed during the 6MWT in patients with stable ILD and COPD. We propose that the American Thoracic Society 6MWT guidelines are revised to recommend continuous monitoring of SpO(2) during the 6MWT in patients with ILD and COPD.

Distal Leg Protection for Peripheral Cannulation in Minimally Invasive and Totally Endoscopic Cardiac Surgery

The introduction of minimally invasive and totally endoscopic cardiac surgery is associated with increased use of femoral artery perfusion. Selective antegrade perfusion of the cannulated artery may be a helpful strategy to avoid ischemia of the lower extremities. The aim of the study was to evaluate the efficacy of selective distal vessel perfusion under continuous monitoring of oxygen saturation using near-infrared spectroscopy (NIRS). All patients (n = 236) who underwent peripheral cannulation for remote access perfusion and endoaortic balloon occlusion for minimally invasive or totally endoscopic cardiac surgery were prospectively analyzed. Perioperative complications, creatine kinase levels, and major complications at the long-term follow-up were recorded. Minor or major complications of leg perfusion occurred in only 4 patients (1.7%); the complications in 2 of the patients were associated with an additional arterial cannula placed at the contralateral side. NIRS monitoring revealed diminished perfusion in 5 cases. Even patients with complications associated with remote-access perfusion had a rapid recovery, and no residual peripheral vascular complication was detected during follow-up. The use of antegrade selective perfusion of the lower extremity at the side of peripheral cannulation for port-access perfusion and endoaortic occlusion is of utmost importance in patients undergoing minimally invasive or endoscopic cardiac surgery. NIRS monitoring has proved to be very helpful for the diagnosis of impaired leg perfusion.