Increased diastolic blood pressure and apnea time contribute to the poor apnea and hypopnea index and life quality of primary snoring: a cohort study combined with external validation

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is a common sleep breathing disorder closely associated with cardiovascular disease. However, the respiratory sleep and related cardiovascular parameters on the apnea and hypopnea index (AHI) and life quality of primary snoring are unclear. We launched a cohort study focused on the association between respiratory sleep and cardiovascular-related parameters and apnea and hypopnea index, incorporating data from 218 patients with primary snoring in our medical center between Jun 1, 2015, and Apr 1, 2016. Thirty patients from Sichuan Cancer Hospital were used for validation. Patients with longer apnea time were more likely to progress to higher AHI (> 30) than controls (OR = 5.66, 95% CI = [2.79, 11.97], p < 0.001). Similarly, if patients have a higher value of diastolic blood pressure, they will also have a higher AHI (> 30) (HR [95% CI] = 3.42 [1.14, 13.65], p = 0.043). According to multivariate analysis, longest apnea time, the mean percentage of SaO2, and neckline length were independent risk factors of overall survival. A predictive model developed based on these factors above yielded a favorable agreement (C-index = 0.872) on the calibration curve. Thirty patients conducted external validation from Sichuan Cancer Hospital, displaying an AUC of 0.833 (0.782-0.884). Increased diastolic blood pressure and apnea time affect AHI level. An AHI prediction model based on these factors above can help clinicians predict the risk of high AHI events.

Predictors of difficult airway in the obese are closely related to safe apnea time!

Background and Aims:

We aimed to redefine the preoperative factors that may challenge the airway and safe apnea time (SAT) in the obese.

Material and Methods:

We analyzed 834 patients with body mass index (BMI) >35 kg/m² for their difficult airway score (DASc). DASc is a consolidation of measures of difficult airway like mask ventilation, difficult intubation, change of device, and number of personnel required. DASc varied from “0” no difficulty to “12” serious difficulty and DASc ≥6 was considered difficult. Preoperative parameters – neck circumference (NC), BMI, STOPBANG score, Mallampati score, obstructive sleep apnea grade, and waist circumference– were assessed.

Results:

Receiver operating characteristic curve was used to identify risk factors for obese patients at DASc ≥6. The Youden index (for the best threshold, with highest sensitivity and specificity) was BMI 45 kg/m² and NC 44.5 cm. Their absence had an 81% negative predictive value to include a difficult airway, while their presence had a positive predictive value of 55%. This further has sensitivity of 66% and specificity of 73%. The mean SAT (256 ± 6 s) was inversely related to DASc (P < 0.001).

Conclusion:

This study demonstrates that BMI and NC have a strong association with difficult airway in obese patients and are inversely related to SAT. Amongst these NC is the single most important predictor of difficult airway in obese and should be used as a screening tool.

The supraglottic airway device as first line of management in anticipated difficult mask ventilation in the morbidly obese

Background and Aims:

Supraglottic airway devices (SGAs) are used to rescue difficult and failed mask ventilation (DMV). We aimed to use the SGA as first-line device, prior to obtaining a definitive airway and to find any predictors of difficulty for the same, in the morbidly obese patients.

Material and Methods:

Obese surgical patients [body mass index (BMI) >35 kg/m²] were investigated. Difficulties with bag mask ventilation (MV) was graded using the following scale: MV-1, one anesthesiologist unassisted could achieve MV and maintain SpO₂>90%; MV-2, one additional anesthesiologist was needed to facilitate MV to achieve SpO₂> 90%; MV-3, two additional anesthesiologists were needed for this purpose; and MV-3P, when a supraglottic device was required to ventilate and maintain SpO₂ more than 90%. Parameters studied were age, gender, neck circumference (NC), BMI, STOPBANG score, and safe apnea time (SAT).

Results:

Logistic regression was performed for predictors of MV-3P; receiver operating characteristic curve was used to locate the best cut-off. Analysis of 834 morbidly obese patients revealed an incidence of MV 1/2/3/3-P as 16%/38%/27%/19%, respectively. DMV was associated with BMI ≥50 kg/m², NC ≥49.5 cm, and STOPBANG ≥6; P < 0.001. The mean SAT for a population with mean BMI 48 ± 8 kg/m² was 256 ± 66 s. The SAT showed inverse relation to BMI and NC. As per our results, the NC was the single most important predictor of MV-3P, with sensitivity 0.62 and specificity 0.85 at best cut-off 49.5 cm; P < 0.001.

Conclusion:

NC ≥49.5 cm is strongly associated with low SAT and need for SGA to achieve MV. SGA may provide safety for initial management following induction of anesthesia in this patient population.

Role of opioids as coinduction agent with propofol and their effect on apnea time, recovery time, and sedation score

Background

Laryngeal mask airway (LMA) is a supraglottic device which requires lesser depth of anaesthesia, evokes lesser hemodynamic response and causes lesser stimulation of airway as compared to traditional definitive airway device endotracheal tube. Its placement is possible without muscle relaxants thereby allowing maintenance of anaesthesia on spontaneous respiration thus preventing apnoea or minimizing apnoea time. Propofol, the commonly used induction agent, causes cardiorespiratory depression at higher induction doses. To attenuate this, co-induction agents combined with propofol has been a regular I/V anaesthetic technique these days.

Aim

Comparing apnoea time, recovery time and sedation scores using propofol-fentanyl and propofol-butorphanol combination.

Methodology

Hundred patients scheduled for various elective surgical procedures were randomly selected and divided into two groups of 50 each. As coinduction drug Group F received fentanyl and Group B received butorphanol. In both the groups induction was achieved with I/V propofol and LMA was placed. Apnoea time was noted after induction. Recovery time and sedation scores were recorded after anaesthetic agents were turned off.

Results

As compared to group F apnoea time was significantly less and recovery time was significantly more in group B (P < 0.05). Statistically postoperative sedation was significantly higher in group B than in group F at 1/2 hr but clinically, majority were responding to verbal commands. At 1 hour no significant difference in sedation was noted between the groups.

Conclusion

Considering respiratory and recovery profile propofol -butorphanol combination is a safer alternative to propofol-fentanyl combination for LMA insertion.