European Journal of Cardiovascular Medicine

With the introduction of endotracheal anaesthesia, a search began for a drug which could cause jaw relaxation to facilitate endotracheal intubation. The first muscle relaxant d-tubocurarine which was non-depolarizing in nature was introduced for jaw relaxation. But it had additional ganglion blocking properties causing tachycardia, hypotension even in clinical doses, with delayed onset making it unsuitable for use during rapid sequence intubation in emergency cases. Succinylcholine chloride introduced in 1951 was a synthetic depolarizing muscle relaxant, choice in rapid sequence intubation in emergency cases. Succinylchloride has adverse effects like hypokalemia, rise in intragastric, intraocular, intracranial pressures and cardiovascular effects. The aim of research on neuromuscular drugs was to have non depolarising muscle relaxant, which is like succinylcholine without its side effects.

Though many nondepolarising muscle relaxant drugs like atracurium besylate, vecuronium bromide and mivacurium chloride were introduced, none of them could challenge succinylcholine chloride in terms of its onset.

The new NDMR drug rocuronium bromide introduced in 1994 became the first competitor for succinylcholine chloride. Rocuronium bromide when given in two to three times the ED95 dose is said to produce excellent to build intubating conditions in 60 secconds. Further rocuronium bromide is said to be devoid of the adverse effects that are seen succinylcholine.

This was a prospective, randomized, single-blinded comparative study conducted from May 2025 to December 2025, at the Department of Anaesthesia, Government Medical College and Hospital, ongole. Institutional ethics committee approval was obtained prior to study commencement. Written informed consent was obtained from all participants. Patients were randomly divided into two groups of 30 each- Group R (Rocuronium bromide) and Group S (Succinylcholine chloride), using a computer generated randomization chart. In operation theatre, intravenous cannula secured and balanced salt solution started. Under standard monitoring, preoxygenated for 3 minutes. Premedicated with injection 3µ/kg of glycopyrolate, 0.02µ/kg of midazolam, 1µ/kg of fentanyl intravenously, induced with titrated doses of propofol till loss of verbal contact. Group R received 0.9mg/kg rocuronium bromide. Group S received 0.9mg/kg succinylcholine chloride. The onset of neuromuscular blockade was assessed using a single twitch stimulation of 0.1Hz every 10sec, after administration of either of the neuromuscular blocking agents. Jaw relaxation, vocal cord movement and cormack Lehane grading were assessed at the time of intubation. Jaw relaxation was graded as good or poor. Presence or absence of vocal cord movement was recorded, visualization of glottis was assessed using Cormack Lehane grade. Cormack Lehane grade:- I- Visualisation of the entire glottic II- Visualisation of just arytenoid cartilage or posterior portion of glottic aperture III- Visualisation of epiglottis only IV- Visualisation of tongue and soft palate only Hemodynamic response to intubation was assessed by recording the preinduction, preintubation and postintubation HR, SBP, DBP and MAP. Inclusion Criteria • American Society of Anesthesiologists (ASA) physical status I and II • Age group of 18-60 years of either sex • Patients posted for surgical procedures under general anaesthesia Exclusion Criteria • ASA physical status III and IV • Patients with renal disease, burns, increased intra cranial pressure, hepatic failure, open eye injuries, cardiovascular, respiratory problems, difficult airway. Data analyzed with SPSS software (25.0). Quantitative variables were expressed as mean and compared using the unpaired Student’s t-test. P-value less than 0.05 was considered statistically significant.

In this study, 60 individuals were divided into 2 equal groups, (n=30 in each group). Baseline parameters were comparable between the groups.

Table 1: Baseline Characteristics of Patients

There were no statistically significant differences in age, weight, height distribution between the two groups.

Table 2 : ASA Physical status

There is no statistical significant difference in the number of ASA physical status I and II patients between the two groups.

Table 3: MALLAMPATI GRADING

Mallampati grading in both the groups were comparable without any statistical significance.

Table 4 : JAW RELAXATION

Incidence of good and poor jaw relaxation were comparable between the two without statistical significance.

Table 5 : VOCAL CORD MOVEMENTS

Vocal cord movements were comparable between the two groups without any statistical significance.

Table 6 : CORMACK LEHANE GRADING

There was no statistically significant difference in cormack Lehane grading between the two group.

Table 7 : ONSET OF NEURO MUSCULAR BLOCKADE

There is statistically significant difference in the onset of action of neuromuscular blockade between group R and group S with faster onset of action in group S.

Table 8: PULSE RATE

There was no statistically significant difference between group R and group S in pre induction and pre intubation  pulse rate.

But there was a statistically significant difference in the post intubation pulse rate between the two groups with more pulse rate in suxamethonium group than rocuronium group .

Table 9 : SYSTOLIC BLOOD PRESSURE

The difference in preinduction, preintubation, postintubation systolic blood pressure among the 2 groups was statistically insignificant.

Table 10 : DIASTOLIC BLOOD PRESSURE

The difference in preinduction, preintubation and postintubation diastolic blood pressure among the 2 groups was statistically insignificant.

Table 11: MEAN ARTERIAL BLOOD PRESSURE

The difference in preinduction, preintubation, postinduction mean arterial blood pressure among the two groups was statistically insignificant.

Endotracheal intubation offers safe conduct of general anesthesia. Inhalational agents were associated with their own adverse effects on organ systems such as sensitization of myocardium to catecholamines by halothane1,2 and hepatotoxicity of chloroform. RSI is performed to secure a definitive airway with in minimum time after ablation of protective airway reflexes with the induction of anaesthesia. This is the technique most frequently employed for patients with full stomach and at risk of gastric aspiration3,4,5.

Succinylcholine has an established role in rapid sequence intubation, but it is not without disadvantages6,7,8. Rocuronium is an alternative to succinylcholine. This study was conducted to comparision of 3 × ED 95 doses of rocuronium bromide and succinylcholine to facilitate endotracheal intubation.

Rocuronium bromide is a steroidal nondepolarizing muscle relaxant that is useful to produce a rapid onset of action9,10,11.

Studies comparing rocuronium and succinylcholine in the onset time and quality of intubation have yielded varying results12,13.

However, the principle can be advocated to shorten the onset time of nondepolarizing muscle relaxants.

The principle entails a rocuronium can be a better and safer alternative to succinylcholine for endotracheal intubation.

Aparna shukla, Dubey et al14 did a randomized prospective control trials using succinylcholine 1.5mg/kg with rocuronium bromide 0.6mg/kg in general anaesthesia in 60 patients. Succinylcholine has an early onset of action than the rocuronium bromide maximum blockade was 46.05 and 80.10 sec. Respectively.

Singh et al15, had shown that with 0.6mg/kg rocuronium and 1.5 mg/kg succinylcholine, the time to achieve maximum blockade was 87.94 and 65.59 sec. respectively. The intubating conditions were comparable in the two groups at 60sec. In our study, the intubating conditions was attained an average of 72.70sec with rocuronium , 59.90 sec with succcinylcholine.

Griffith et a16, compared succinylcholine 0.06mg/kg with rocuronium 0.9mg/kg and time to achieve maximum blockade was 45.94 and 85.59 secs. respectively. In our study the intubating condition was attained an average of 72.7 sec with  rocuronium, 59.9 sec with succinylcholine.

Madhavi barve et al17, evaluated onset of time, tracheal intubating condition and clinical duration of muscle relaxant in a randomized prospective study conducted in 40 patients. They were given either rocuronium bromide 0.6mg/kg, succinylcholine 1mg/kg. It was quantified by recording twitch response od adductor pollicis evoked after supramaximal stimulation of ulnar nerve using acceleromyogram. Onset time and duration of action were significantly more in rocuronium bromide group 101.50 sec, than succinylcholine 63.75 sec.

Weiss et al, in a double blind study compared two doses of rocuronium bromide and succinylcholine for RSI. Patient received either rocuronium bromide 0.7mg/kg or 0.9mg/kg or  succinylcholine 1.5mg/kg. The ease of intubation was scored using a scale of 1 to 4. BP,HR were measured beginning one minute before induction of anaesthesia up to 5 minutes after intubation. Rocuronium bromide at a dose of 0.9mg/kg provides intubating conditions similar to succinylcholine 1.5mg/kg at 1 minute. Intubating conditions at 1 minute following a 0.7mg/kg dose of rocuronium bromide are not as good as those following 1.5mg/kg dose of succinylcholine.

In our study the BP,HR were measured preinduction,preintubation and postintubation. There was no statistically significant difference between rocuronium group and succinylcholine group in preinduction and preintubation pulserate.

But there was statistically significant difference in the postintubation pulserate between the two groups with more pulserate in suxamethonium group than rocuronium group.

Scheider et al, compared rocuronium bromide 0.6mg/kg, vecuronium 0.1mg/kg and atracurium 0.5mg/kg. Rocuronium produce acceptable intubating conditions significantly faster than vecuronium and atracurium. Onset of action muscle relaxantion for rocuronium 92sec, vecuronium 112 sec and atracurium 134 sec. We conclude that clinically acceptable intubating conditions are produced more rapidly with rocuronium bromide than with atracurium and vecuronium.

In our study, we compare rocuronium bromide 0.9mg/kg and succinylcholine 0.9mg/kg. Onset of neuromuscular blockade was faster with succinylcholine 59.97sec than the rocuronium bromide 72.87sec.

Magorian et al18  concluded that succinylcholine is the agent of choice in emergency airway protection during RSI. They compared three intravenous doses of rocuronium bromide - 0.6, 0.9, 1.2 mg/kg., vecuronium 0.1mg/kg and succcinylcholine 1.0mg/kg. They observed the onset of action in patient receiving rocuronium 0.9mg/kg (75sec.), 1.2mg/kg (55sec.), succinylcholine 1.0mg/kg (50sec.). rocuronium bromide 0.6mg/kg (89sec.), vecuronium 0.1mg/kg (144sec.) had significantly longer onset time.

Neuromuscular block was early in succinylcholine group than rocuronium group as found in our study.succinylcholine has a early onset of action than the rocuronium bromide with time to achieve maximum blockade of 46.05sec and 80.01sec in succinylcholine and rocuronium bromide groups respectively.

In a study by Sg Chavan et al19, the effect of rocuronium bromide at two different doses that is 0.6mg/kg and 0.9mg/kg were compared with succinylcholine 2 mg/kg, when used for endotracheal intubation in adult patients. On set of neuromuscular block was rocuronium bromide 0.6mg/kg (115.50sec.), 0.9mg/kg (74sec.) and succinylcholine 2mg/kg (53.25sec.). duration of action when the dose of rocuronium bromide is increased from 0.6 to 0.9mg/kg.

In our study, we found similar results as the above study, but we studied only two groups that is rocuronium bromide 0.9mg/kg and succinylcholine 0.9mg/kg. Succinylcholine has an early onset of action than the rocuronium bromide with time to achieve maximum blocked of 46.05 sec. and 80.01sec. In succinylcholine and rocuronium bromide groups respectively.

Yavascaoglu et al20, has proved that priming with the 3minute priming interval was more effective than the 2 minute priming interval.

In our study no priming dose.        

One of the major drawbacks of priming dose is the occurrence of adverse effects such as weakness, diplopia, dysphagia, generalized discomfort and breathing difficulties.

Meistelman et al21, studied the onset of neuromuscular blockade with rocuronium at the laryngeal adductor muscles and adductor pollicis in 14 adult patients. With rocuronium 0.25mg/kg, the onset time was 1.6 ± 0.1 min. and 3.0 ± 0.3 min. at the laryngeal adductors and adductor pollicis respectively.

With 0.5mg/kg, the onset time was also more rapid at the vocal cords (1.4 ± 0.1 min. ) than at the adductor pollicis ( 2.4 ± 0.2min.). they concluded that the onset of action as well as recovery was faster at the laryngeal adductor muscles, but that blockade was less intense than at the adductor pollicis.

We choose the adductor polliciss muscle for monitoring neuromuscular blockade in our study for the ease of monitoring.

In our study we monitored the neuromuscular blockade at the level of adductor pollicis. However there is evidence to show  that the adequate neuromuscular blockade occurs faster at the level of vocal cords than at adductor pollicis.

The difference in the onset times among various studies may be attributed to the different modes used ( TOF or single twitch ), frequency of nerve stimulation, anaesthetic drugs and study population.

Rao et al22, compared the intubating conditions between rocuronium  and succinylcholine. They found no increase in HR or blood pressure following rocuronium 0.9mg/kg, succinylcholine 0.6mg/kg onset of neuromuscular blocked than the rocuronium bromide. They observed a slight increase in HR and mean arterial pressure 1 min postintubation, which was attributed to stress response to intubation.

Shorten et al23, performed a comparative study in elderly patients given rocuronium 0.9mg/kg and  vecuronium 0.12mg/kg and found no significant change in HR, arterial blood pressure.

In our study, the hemodynamic variables measured at baseline, immediately after intubation, 1min and 5mins.  Following intubation showed little variation between the two groups which was of course statistically insignificant variations among the two groups. This was in agreement with the study by Rao et al22.

We assessed the absence of response to twitch stimuli just before intubation. Intubating conditions were graded as excellent, good and poor depending on the intubation score. All the patients in this study had excellent intubating conditions. The outcome was similar in studies conducted by Naguib et al. Rao et al22. and Griffith et al16.

The present study showed that when 3 × ED 95 dose of rocuronium bromide and succinylcholine were used to facilitate endotracheal intubation, succinylcholine showed an early onset muscle relaxation than rocuronium bromide. There was no difference in jaw relaxation and vocal cord movement at the time of intubation between the two drugs. There was no difference in hemodynamic response to intubation between the two drugs except for more increase in pulse rate with rocuronium bromide than with succinylcholine. ACKNOWLEDGEMENTS: The authors would like to acknowledge the support given by the staff while conducting this study. CONFLICTS OF INTEREST: None declared.

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