Effect ofclonidine on heart rate variability during spinal anaesthesia: randomized clinical trial.

Background: Combined spinal epidural anesthesia (CSE) combines the rapid onset and intensity of a subarachnoid blockade with the flexibility of an epidural catheter, thereby allowing the intraoperative extension of anesthesia and postoperative epidural analgesia.This study investigated the effects of hyperbaric bupivacaine during CSE for lower limb orthopedic surgery in geriatric patients.Methods: Group 1 received a subarachnoid injection of 8 mg of bupivacaine and an epidural catheter.Group 2 received a subarachnoid injection of 5 mg of bupivacaine and fentanyl, 10μg and an epidural top-up with 3 ml saline.Group 3 received a subarachnoid injection of 5 mg of bupivacaine and fentanyl 10μg with an epidural top-up of 6 ml saline.Group 4 received a subarachnoid injection of 6 mg of bupivacaine and an epidural top-up with 6 ml saline.The maximal level of the sensory blockade, the time of onset to the maximal sensory blockade, the two segment regression time, the time for sensory regression to the tenth thoracic dermatome (T10) and the motor recovery to modified Bromage Scale 0 were compared.After recording the baseline systolic blood pressure and heart rate, the systolic blood pressure and heart rate were recorded at 5 min intervals.Results: There were significant differences in the two-segment regression times, the times to motor recovery between the groups.However, the intraoperative blood pressure and heart rate were similar.Conclusions: In terms of the peri-operative side effects and recovery from the blocks, CSE was better for lower limb orthopedic surgery in geriatric patients than spinal anesthesia.(

Spinal anesthesia is an old, simple, and popular anesthetic technique, yet much remains unknown regarding pertinent anatomy, physiology, and pharmacology. Investigations into physiologic effects of spinal anesthesia reveal complex actions on multiple organ systems. New local anesthetics, analgesic additives, and techniques are being investigated for different applications as the practice of medicine focuses on outpatient care. Safety of spinal agents and complications from spinal anesthesia continue to be examined and re-examined to improve safety. Further study will be needed to fully resolve these issues and to further understand and improve the clinical use of spinal anesthesia.

The purpose of this study is to determine if spectral analysis of beat-to-beat heart rate variability will provide important data on autonomic nervous system function during either spinal or epidural anesthesia that is not apparent from the monitoring of mean heart rate and blood pressure. Twelve ASA I patients presenting for elective cesarean delivery (7 epidural and 5 spinal anesthetics) were prospectively selected for study. Control and postblock 10-minute segments of instantaneous heart rates were analyzed for each patient. The total spectral power (Ps, 0.02-0.5 Hz), low frequency spectral power (PLF, 0.02-0.12 Hz), and high frequency spectral power (PHF, 0.12-0.5 Hz) were calculated for each data segment. The complexity of the heart rate time series was estimated by calculating the approximate entropy. Neither spinal or epidural anesthesia had any effect on heart rate or blood pressure. Both spinal and epidural anesthesia did produce a significant decrease in PS, PLF, and PHF. Although there were significant decreases in both the PLF and PHF, there was no change in the PLF/PHF ratio. There was a significant reduction in approximate entropy with spinal and epidural anesthesia, indicating a decrease in complexity of the heart rate dynamics. These data suggest that autonomic tone decreased with spinal and epidural anesthesia but the sympathetic-parasympathetic balance (expressed as PLF/PHF) did not change. Spectral measures, as well as approximate entropy, provide an independent evaluation of the integrity of the autonomic nervous system and cardiovascular control mechanisms that cannot be discerned from mean heart rate and blood pressure.

Spinal anesthesia provides several benefits for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA), but historically comes at the cost of slow and unpredictable return of lower-extremity motor function related to the use of long-acting local anesthetics. In this prospective, double-blinded, randomized clinical trial we sought to determine if an alternative local anesthetic, mepivacaine, would allow more consistent return of motor function compared with low-dose bupivacaine spinal anesthesia during primary THA and TKA. This trial was conducted at a single academic institution. Prior to trial initiation an internal pilot study determined that 154 patients were required to achieve 80% power. Patients were randomized in a 1:1 fashion with use of advanced computerized stratification based on procedure, age group, sex, and body mass index. Following the surgical procedure, motor function was assessed every 15 minutes in the nonoperative lower extremity according to the Bromage scale and discontinued once Bromage 0 was achieved (spontaneous movement at hip, knee, and ankle). Return of lower-extremity function was more predictable in patients who received mepivacaine than in those who received low-dose bupivacaine. Among patients who received mepivacaine, 1% achieved motor function return beyond 5 hours compared with 11% of patients who received bupivacaine (p = 0.013). The mean time to return of lower-extremity motor function was 26 minutes quicker in patients who received mepivacaine (185 minutes; 95% confidence interval, 174 to 196 minutes) compared with low-dose bupivacaine (210 minutes; 95% confidence interval, 193 to 228 minutes) (p = 0.016). There were no significant differences in safety outcomes including pain scores, time to participation in physical therapy, incidence of orthostatic hypotension, urinary retention, or transient neurologic symptoms in patients receiving mepivacaine compared with low-dose bupivacaine. In patients undergoing primary THA and TKA, spinal anesthesia with mepivacaine allowed more consistent return of lower-extremity motor function compared with low-dose bupivacaine, without a concomitant increase in complications potentially associated with spinal anesthetics. This is particularly of value in an era of short-stay and outpatient surgical procedures. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Obstructive sleep apnea (OSA) is a common disorder which can cause periodic fluctuations in heart rate. To diagnose sleep apnea, some studies analyze electrocardiogram (ECG) signals by adopting chaos-based analysis. This research is going to specifically focus on whether it is possible to use chaos-based analysis of heart rate variability (HRV) signals rather than using chaotic analysis of ECG signals to diagnose OSA. While conventional studies mostly use chaos-based analysis of ECG signals to detect OSA, here, we apply correlation dimension (CD) as a chaotic index to analyze HRV data in OSA patients. For this purpose, 17 patients with OSA and 9 healthy individuals referred to a sleep clinic in Isfahan/Iran are studied, and their HRV time series were extracted from 1-h ECG signals recorded overnight. The preliminary step to calculate CD is phase-space reconstruction of the system based on HRV time series. Corresponding parameters, including embedding dimension and lag time, are estimated optimally using enhanced related methods, and then CD is calculated using Grassberger–Procaccia algorithm. Moreover, to evaluate our results, detrended fluctuation analysis (DFA), one of the well-known nonlinear methods in HRV analysis to detect OSA, is also applied to our data and the result is compared with those obtained from CD analysis of HRV. CD index with P < 0.005 indicates a significant difference in nonlinear dynamics of HRV signals detected from OSA patients and healthy individuals.

Combination of local anesthetic and opioid enables the use of less spinal anesthetic and increases the success of anesthesia. Intrathecal opioid does not prolong motor recovery and thus should not delay discharge home. We hypothesized that 3 mg of hyperbaric bupivacaine with 10 microg of fentanyl permits fast-tracking or shorter stay in post anesthesia care unit (PACU), and earlier discharge home, compared with 4 mg of hyperbaric bupivacaine. In this double-blind study, 100 outpatients undergoing knee arthroscopy received randomly either 4 mg of bupivacaine (B4) or 3 mg of bupivacaine + 10 microg fentanyl (B3F) intrathecally. The volume of 0.8 ml was injected at the L2/3 interspace over a 2-min period. A lateral decubitus position was maintained for 10 min. The sensory block was recorded by using thermal stimuli, and motor block was assessed according to a modified Bromage scale. Fast-tracking criteria were complete recovery of motor block, sensory block Th12 or lower and stable vital signs. One block (1%) failed. Motor recovery was faster in the B3F group: 60% of the patients recovered in 80 min or less compared with 28% in group B4 (P = 0.002). The PACU-time was shorter: 36 (10-103) vs. 55 (10-140) min, respectively (P = 0.005). Seventeen (B3F) vs. nine patients (B4) could bypass PACU (NS). Time to discharge home was similar in both groups. In the B3F group, 75% of the patients developed pruritus. Both solutions produced reliable spinal anesthesia for outpatient knee arthroscopy. The PACU-time was shorter in the bupivacaine-fentanyl group, but both groups reached home-readiness equally.

Discharge From the Postanesthesia Care Unit With Motor Blockade After Spinal Anesthesia Safely Optimizes Fast Track Recovery in Primary Total Hip and Knee Arthroplasty

AIM:In this study we aimed to find out the heart rate variability measuring using electrical cardiometry is not reliable as a predictor for hypotension following spinal anesthesia in preeclamptic parturients undergoing elective cesarean section.METHODS:Electrical Cardiometry system was used to measure Heart rate variability (HRV) at five different time points before fluid loading (T0, baseline), after fluid loading (T1), 5 min after spinal anaesthesia (T2), 15 min after spinal anaesthesia (T3) and 30 min after spinal anaesthesia (T4). Traditional HRV measurement was determined using time-domain analysis. This Observational descriptive cohort study was conducted in Kasr Al-Ainy Hospital, Faculty of Medicine, Cairo University from February 2018 till June 2019, after approval of the Ethical Committee and written patients consent.RESULTS:The main finding of the current study is that heart rate variability measuring using electrical cardiometry is not reliable as a predictor for hypotension following spinal anaesthesia in preeclamptic parturients undergoing elective cesarean section.CONCLUSION:Heart rate variability cannot be used as a predictor for hypotension following spinal anaesthesia in preeclamptic patients undergoing elective caesarean section using electrical cardiometry.

Heart Rate Variability (HRV) is a widely accepted technique used to measure the stress level of individuals. The state of the art HRV features namely Hilbert spectral and Detrended Fluctuation Analysis (DFA) estimates have opened ways to measure mental state of the individual. The HRV spectral estimates Instantaneous Amplitude of Low Frequency band (LFiA) & Instantaneous Amplitude of High Frequency band (H FiA) derived from Hilbert Transform provides better categorization of mental stress states than conventional frequency parameters due to joint 2-D representation of the low and High frequency HRV bands. Another HRV based approach DFA, which is robust against non-linearity and non-stationarity of cardiac time series caused by complex interactions, helps in providing reliable HRV interpretation. Based on the research evidences for both Hilbert and DFA estimates, it was observed that the use of Hilbert spectral estimates in stress assessment was not validated under free living condition and the application of DFA for mental stress assessment of individuals was not studied. In this work the utility of Hilbert Transform and DFA in HRV based stress assessment was studied under two different settings (confined and free living). The first objective was to determine whether DFA can be used to delineate between two mental states (baseline and stress), under both confined and free living conditions, and to quantify its discriminatory power in the context of mental stress detection. The second objective was to examine the utility of Hilbert estimates in determining mental state under free living conditions. The third objective was to compare the discriminatory power of DFA and Hilbert Transform in stress state detection. From this study, it was observed that both Hilbert and DFA methods can be used to delineate between two mental states under both confined and free living conditions. From the comparative analysis, it was observed that Hilbert estimates showed better discriminatory power than DFA under both the settings.

Hypotension is common after spinal local anaesthesia for caesarean section. However, the substandard treatment of spinal hypotension and associated complications are responsible for up to two-thirds of deaths that occur in South Africa (SA) for caesarean section under spinal anaesthesia. In some cases, spinal hypotension may be predicted by simple parameters such as age &gt;25 years, preoperative heart rate &gt;90 bpm and preoperative mean arterial pressure &lt;90 mmHg. Heart rate variability and point-of-care echocardiography also predict hypotension with greater accuracy, but are limited by equipment and training issues. Spinal anaesthesia is absolutely contraindicated if the parturient is hypovolaemic. Left lateral tilt is still advised, despite the absence of strong supporting evidence. The dose of spinal bupivacaine should not be reduced in obese patients. Crystalloid co-loading is an adequate fluid strategy in most cases, but is of limited efficacy in the prevention of hypotension. It is imperative that immediately after the patient is placed supine, close attention is paid to communication with her, heart rate changes and pulse volume. Early intervention with phenylephrine is the first-line approach for hypotension if heart rate is preserved under spinal anaesthesia. Phenylephrine infusions (25 - 50 μg/min) are easy to administer, maintain baseline maternal haemodynamics and are applicable to the SA context. The vigilant use of phenylephrine boluses (50 - 100 μg), targeting maternal heart rate as a surrogate for cardiac output, is also effective. Noradrenaline has been used successfully to prevent spinal hypotension, but evidence does not yet suggest practice change. Local and international guidelines have recently been published.

Background: Local anesthetic drugs like bupivacaine are commonly used in spinal anesthesia for lower limb surgeries but the duration of spinal anaesthesia is very short. However, the duration of action of bupivacaine in spinal anaesthesia can be prolonged by using adjuvants such as midazolam, opioids, neostigmine, dexmedetomidine and clonidine. The present study is being undertaken to evaluate and compare the effects of clonidine and fentanyl as intrathecal adjuvants to hyperbaric bupivacaine in patients undergoing lower limb orthopaedic surgery. Material and Methods: Present study was conducted in the Department of Anaesthesiology and Intensive Care, Government Medical College, Jammu in patients of either sex ranging in age from 20-60 years belonging to ASA I/ II scheduled for lower limb orthopaedic surgeries. 90 patients were randomly allocated in three groups of 30 each in order to compare the duration and quality of analgesia of clonidine and fentanyl used as adjuvants to intrathecal bupivacaine. Results: All the three groups were comparable in age, gender, height, weight, ASA grade distribution and the difference between them was not statistically significant. The difference between the time to reach the T10 block, mean time taken for first request for analgesia and duration of motor block in all three groups were found out to be statistically significant (p&lt;0.0001). It was found that group with clonidine had better results than fentanyl and bupivacaine alone. In our study 1 patient in bupivacaine (15mg) with fentanyl (25µg) group and 2 patients in clonidine(37.5ugm) group had hypotension but the difference was statistically insignificant. Only 1 patient in each fentanyl and clonidine group had 1 episode of bradycardia but no patient in bupivacaine alone group had bradycardia and the difference was also insignificant. Postoperative vomiting was experienced by 3.33% of patients receiving Bupivacaine (15mg) with fentanyl (25µg) and it was treated by giving injection Ondansetron 4 mg i/v whereas no case was reported in clonidine group. This difference was statistically insignificant. 2 patients in bupivacaine (15mg) with fentanyl (25µg) group had itching but no such case was reported in clonidine group and the difference was also statistically insignificant. No respiratory depression, nausea was noted in study patients. Conclusion: It can be concluded that intrathecal clonidine (37.5ugm) provides quicker onset and prolonged duration of sensory and motor blocks simultaneously increasing the duration of analgesia when compared to fentanyl (25ugm).

On the body surface the electric field generated by the cardiac muscles consists of electric potential maxima and minima that increase and decrease during each cardiac cycle. The recording of these electric potentials as a function of time is called electrocardiography, and the resulting signal is called the electrocardiogram (ECG). The ECG signal is used extensively as a low cost diagnostic tool to provide information concerning the heart's state of health. Reliable and accurate detection of the QRS complex and R wave peak in ECG signals is essential in computer-based ECG analysis. In this paper we evaluate the significance of Detrended Fluctuation Analysis (DFA) for studying heart rate variability in children with sleep disordered breathing. An Enhanced Hilbert Transform (EHT) algorithm was used to derive the Heart Rate Variability (HRV) signal. We compare the DFA values with Approximate Entropy and Poincaré Plots of HRV signals as these are very useful in characterization and visualization of HRV data. Our data demonstrated differences in DFA parameters between periods of normal and abnormal breathing and also between sleep stages. These results suggest that DFA is suitable for the long-term analysis of non-stationary time series such as HRV signals and may also be applied in the detection of sleep disordered breathing.

Background: Spinal anesthesia is a widely used technique for lower abdominal surgeries, offering rapid onset, reliable analgesia, and minimal systemic effects. The combination of local anesthetics like bupivacaine with opioids such as fentanyl has been shown to enhance the quality and duration of analgesia. This study aims to compare the perioperative and postoperative outcomes of conventional-dose versus low-dose bupivacaine combined with fentanyl in spinal anesthesia for open cholecystectomy. Methods: This prospective observational study was carried out at North Bengal Medical College Hospital from January 2021 to December, 2023, including 150 patients undergoing open cholecystectomy under spinal anesthesia. Participants aged 18–65 years with ASA physical status I or II were divided into two groups: Group A (conventional-dose) received 15 mg of Bupivacaine with 25 µg Fentanyl, while Group B (low-dose) received 7.5 mg of Bupivacaine with the same dose of Fentanyl. Data were analyzed using SPSS version 26.0. Result: Demographic variables were comparable across groups (p &gt; 0.05). Group B achieved significantly faster onset of sensory block (T3) and had higher incidence of bradycardia (p &lt; 0.005), while Group A showed a trend toward more hypotension. Sensitive and motor block durations were significantly longer in Group A (p &lt; 0.005), indicating denser anesthesia. No significant differences were noted in shoulder pain, nausea, vomiting, or pruritus. Conclusion: This study demonstrates that using a low dose of bupivacaine (7.5 mg) with 25 µg fentanyl results in fewer perioperative and postoperative complications compared to the conventional dose (15 mg). The conventional-dose group had a higher incidence of shoulder pain, hypotension, and need for rescue fentanyl, particularly during the perioperative period. Nausea and vomiting were slightly more frequent in this group, while bradycardia was comparable between both groups.

Combination spinal analgesic chemotherapy: a systematic review.

Differences in mean and variability of heart rate and ambulatory rate-pressure product when valsartan or carvedilol is added to lisinopril