Hemodynamic stress response with laryngeal mask airway insertion and tracheal intubation in hypertensives patients undergoing mastectomy

 

Abstract               Laryngeal and endotracheal intubation results in hypertension, tachycardia and arrhythmias and are more hazardous in patients with hypertension, myocardial infarction, coronary artery disease, cerebrovascular disease, penetrating eye injuries and intracranial lesion. Use of laryngeal airway requires neither visualisation of vocal cords nor the penetration of larynx with less sympathetic response and catecholamine release. Material And Methodology: Hundred Hypertensive (systolic BP </=140 mm Hg) female patients of 30-70 yrs of age , ASA I and II, with MPG I and II, posted for mastectomy were divided in two groups LMA (50),ETT (50). Heart rate, SBP, DBP were measured and post operative complication observed. Results: Heart rate, SBP and DBP increased in both group but in LMA group decreased to baseline in 3min and in ETT group decreased at 5min, Duration for insertion of LMA(12.76sec) was lesser as compared to ETT group(23.72sec). The incidence of postoperative sore throat, hoarseness, coughing is less in LMA group as compared to ETT group. Conclusion: hemodynamic response, was significantly in LMA group. Thus, LMA is a useful alternative to endotracheal intubation.

Key Word: Laryngeal mask airway, Endotracheal intubation, Hypertension, Mastectomy, hemodynamic response.

 

 

INTRODUCTION

Laryngeal and endotracheal intubation is the commonest method of securing definitive airway for administering anesthesia. This will increase sympatho-adrenal activity resulting in hypertension, tachycardia and arrhythmias.^1,2,3,4 Although these hemodynamic response are more concerned in hazardous in patients with hypertension, myocardial infarction, coronary artery disease, cerebrovascular disease, penetrating eye injuries and intracranial lesion.^4,5 Techniques that cause minimal oropharyngeal airway stimulation also attenuate the hemodynamic response.⁵ Use of laryngeal airway in place of endotracheal tube requires neither visualisation of vocal cords through laryngoscopy nor the penetration of larynx making the placement less stimulating than tracheal intubation and it may provoke less sympathetic response and catecholamine release.⁶ Thus this study was designed to compare hemodynamic stress responses to laryngeal airway insertion and endotracheal intubation, to evaluate the ease of laryngeal mask airway insertion, to evaluate the efficacy and usefulness of laryngeal mask airway over tracheal intubation and to study associated complications.

 

MATERIAL AND METHODOLOGY

After getting institutional review committee approval and a written informed consent , a total of 100 hypertensive female patients undergoing mastectomy were randomly allocated to two groups: Inclusion criteria were hypertensive female patients of 30-70 years of age undergoing mastectomy , ASA I and II, MPG I and II, willing to participate in the study by giving consent, baseline systolic BP </= 140 mm Hg. Exclusion criteria were normotensive patients and hypertensive patients with baseline systolic pressure >140 mm Hg, ASA III and IV, MPG III and IV or having distorted or abnormal oral or supraglottic anatomy, h/o respiratory infections, difficult intubation ,angina , palpitations, syncopal attacks, hepatic and renal problems, regurgitation prone conditions, obese, full stomach patients and unwilling to participate in the study.

Group LMA- LMA was inserted (50 patients)

Group ETT- Endotracheal tube intubation was done (50 patients)

Pre operative evaluation: All the patients were examined preoperatively and the procedures explained and written informed consent was taken. Routine investigations were done. They were kept NBM atleast 8 hrs prior to surgery.

Premedication: Tab Lorazepam 1 mg given at 10 pm on the night before surgery. Antihypertensive drugs were given at 6 am on the morning of surgery.

Monitoring: All routine monitors were applied before induction. Heart rate, systolic and diastolic blood pressure were noted. I.V line was secured, Inj. Ranitidine 1mg/kg and Inj. Glycopyrrolate Bromide 0.004mg/kg was given i. v

Induction: Patients in both groups received preoxygenation via face mask for 5min.and were induced with inj. fentanyl citrate 2µg/kg, inj. Propofol 2mg/kg i.v and after confirming loss of eye lash reflex, Succinylcholine 2mg/kg i.v was given for Endotracheal tube (ETT) or Laryngeal mask airway( LMA) insertion. After the disappearance of fasciculations, LMA size 3 was inserted in group LMA and tracheal intubation with ET tube size 7.0/7.5 was done in group ETT. 2% Xylocaine gel was used as a lubricant for both the endotracheal tube cuff and LMA cuff. Air was injected into the endotracheal tube or LMA cuff as per recommendation. The position of LMA/ETT was assessed by chest rise on manual ventilation, equal air entry on auscultation and capnograph tracing. Duration of insertion / intubation was defined as the time from the start of insertion / intubation until inflation of cuffs. LMA insertion grading were done according to ease of insertion. Ease of insertion was classified as: Excellent (no resistance to insertion) Good (slight resistance to insertion ) Poor ( moderate resistance to insertion ) Impossible.

Ease of intubation was graded I-IV according to the criteria of Cormack and Lehane.

1. Grade 1- visualization of entire vocal cords
2. Grade 2-visualization of posterior part of laryngeal aperture.
3. Grade 3-visualization of epiglottis.
4. Grade 4-no glottic structures seen.

Maintenance: O₂ + N₂O (50:50) + sevoflurane. No additional drugs were given till 5 mins. Before 30 mins of completion of surgery, Inj. Diclofenac sodium 1.5 mg/kg i.m and Inj. Ondansetron 0.1 mg/kg i.v were given.

Reversal was done with Inj. Neostigmine 0.05mg/kg i.v + Glycopyrrolate 0. 4mg i.v.

Observation: Heart rate, systolic and diastolic blood pressures are noted preoperatively and before induction and at Preintubation/insertion, intubation/insertion, 1 min, 3mins, 5mins after intubation/insertion.

Intraoperative complications: Injury to tongue, lips, teeth was noted

Post operative complications: Laryngospasm, regurgitation if any was accounted. Patients were asked about sore throat (constant pain independent of swallowing), hoarseness and or pain during phonation (as voice complaints). These along with cough were evaluated at 12 hrs and 24 hrs in both the groups.

Statistical Analysis: Statistical analysis was done using graphed software. P value for age and height and time of insertion/intubation was calculated using student unpaired ‘t’ test. Statistical data for haemodynamic parameters was calculated using student paired ‘t’ test within the same group, between the groups using student unpaired ‘t’ test. P value for ease of insertion and intraoperative complications is calculated using chi –square test. P value for post operative complications is calculated using fisher’s exact test. P value<0.05 was considered significant.

OBSERVATIONS AND RESULTS

Table 1: Demographic data and mean duration of insertion/intubation of LMA and ETT

{ACE inhibitors= angiotensive converting enzyme inhibitors, ARBs= angiotension receptor blockers, CCBs=calcium channel blockers} The two groups were similar in terms of age, weight and anti hypertensive drugs with statistically insignificant P value. The mean duration of insertion of LMA and ETT was statistically significant (p<0.0001).

 

Figure 1: Comparison of Mean Heart rate between LMA and ETT groups

The above chart shows changes in mean heart rate associated with LMA insertion and ETT intubation. Pre insertion/intubation values are taken as baseline values.

• Heart rate of two groups were comparable at baseline as p is >0.05 which is not statistically significant.
• At insertion/intubation, increase in heart rate was observed in both the groups, more in ETT group.
• This increase returned to baseline value at 3 mins in the LMA group, where as it took 5 mins for the heart rate to come to baseline values in the ETT group.
• At 5 mins, heart rates, in both groups were comparable as p-0.1892.

Figure 2: Comparison of Mean Systolic Blood Pressure between LMA and ETT Groups.

 

The above chart shows changes in Mean Systolic Blood pressure associated with LMA insertion and ETT intubation.

Pre insertion/intubation values were taken as baseline values.

• The mean SBP of two groups were comparable at baseline as p was >0.05 which is not statistically significant.
• At insertion/intubation, increase in SBP was observed in both the groups, more in ETT group.
• This increase returned to baseline values at 3mins in the LMA group, whereas it took 5 mins for the SBP to came to baseline values in the ETT group.
• At 5 mins, SBP in both the groups were comparable as p-0.0864.

Figure 3: Comparison of Mean Diastolic Blood Pressure between LMA and ETT Groups

The above chart shows changes in mean diatolic blood pressure associated with LMA insertion and ETT intubation

Pre insertion/intubation are taken as baseline values.

• The mean DBP of two groups were comparable at baseline as p is >0.05 which is not statistically significant
• At insertion/intubation, increased in DBP is observed in both the groups, more in ETT group.
• This increase returned to baseline values at 3mins in the LMA group, whereas it took 5 mins for the DBP to came to baseline values in the ETT group.
• At 5 mins, DBP in both the groups were comparable as p-0.8786.

The occurrence of injury to lip, tongue, teeth was more in ETT group(70%) compared to LMA group(20%) as p value is significantly higher (p<0.0001).

 

Table 4: Post operative complications

occurrence of sore throat was statistically significant (p-0.0439) at 12 hrs when compared between the two groups, which at 24 hrs is statistically insignificant (p-0.7858) The occurrence of hoarseness and coughing were also statistically significant in the ETT group at 12 hrs and 24 hrs.